bluuebunny/crossref_metadata_2025 huggingface dataset:
Material properties and broadband backscatter measurements of individual euphausiids from the California coastal ecosystem
Authors: Warren Joseph , Lucca Brandyn M.
Published: April 2023

During the 14–24 May 2019 leg of the NOAA juvenile rockfish survey, zooplankton and small nekton were sampled off the coast of Northern California using a midwater trawl. This talk will focus on three euphausiid species (E. pacifica, T. spinifera, N. difficilis) which were present in most catches. Krill morphology (size and shape) and animal density relative to seawater were measured for 175 live (or very recently expired) individuals. Roughly 150 individual krill were frozen and brought back to land for mass measurements. Soundspeed relative to seawater was measured for 15 mixed-species aggregations of krill. Broadband (38–73 and 130–210 kHz) and narrowband (38, 50, 70, 120, 150, and 200 kHz) backscatter measurements were made on 32 live (or very recently expired) individual krill. These empirical measurements were then compared to predictive backscatter measurements using scattering model parameters measured for those individuals (when available). Differences between predicted and measured backscatter were generally small, although there were individual krill where measurements at some frequencies varied significantly (i.e. more than 3dB). Understanding the variability in scattering model inputs among and within these species, and the accuracy of scattering model predictions provides context (i.e. uncertainty estimates) for acoustic measures (or indices) of krill biomass.
Cavitation noise characterization and classification using machine-learning techniques
Authors: Usadi Lillian N. , Raymond Jason L. , Wong Cherie , Wu Qiang , Gray Michael , Stride Eleanor P. , Roy Ronald A. , Kwan James
Published: April 2023

Noise characterization of cavitation has use in biomedicine, sonochemistry, and waste degradation. Typically, spectral features of the cavitation noise signals obtained through Fourier analysis are specific to the experimental set-up and are analyzed to classify the signals in terms of presumed domains of bubble behaviors. The objective of this research was to develop the experimental capabilities and algorithm to monitor and classify cavitation a priori using machine learning (ML) in a precise, repeatable, and translatable fashion among various setups and applications. Initially, simultaneous high-speed videos and passive acoustics maps were acquired for a single oscillating bubble in a simple setup. Machine learning methods such as support vector machine and convolutional neural networks were used to classify the acoustic data and train a classification algorithm. The algorithm was then adapted for a novel sonochemical reactor that induces spontaneous cavitation nucleation and utilizes a passive cavitation detector to monitor cavitation noise. Further research will be done in correlating potassium iodide (KI) degradation with frequency spectra using ML classification in order to optimize the sonochemical efficiency.
Exploring speech characteristics for automatic pathological voice detection
Authors: Wloszczynska Martyna , Kostek Bozena
Published: April 2023

This paper aims to explore speech characteristics for automatic pathological voice detection. First, the assumptions underlying the conducted experiments are presented, along with examples of databases containing pathological speech. Then, a selection process of features of the speech signal and algorithms used to distinguish between undisturbed and pathological speech are discussed. Two deep models are employed to perform binary classification of the speech signal. Their structure is presented along with the feature space chosen. The results of classifying undisturbed and pathological speech are compared with state-of-the-art literature sources. The accuracy values are comparable to those presented in the literature, i.e., they are within the range of 61%–71% for our research and 64%–98% for the literature data, depending on the algorithms and databases used. An application is also built to illustrate the speech recognition process. The experiments are summarized with conclusions, and the direction of possible future development of the research performed is given.
Dynamic control of the acoustic scene in echolocating bats
Authors: Jakobsen Lasse , Häfele Felix T. , Wisniewska Danuta M.
Published: April 2023

Echolocating bats can detect, localize, classify, pursue, and capture night-flying insects in less than a second. During pursuit, aerial hawking bats dynamically change their emitted calls as they approach prey, increasing call rate, reducing call duration, increasing bandwidth, and reducing source level. Additionally, many bat species dynamically control the shape of the emitted echolocation beam by broadening the beam in close proximity to prey. However, the acoustic scene, as experienced by the bats, depends as much on the characteristics of the emitted call as on the shape and orientation of the outer ears. We show that aerial-hawking bats also dynamically modify the shape and orientation of the outer ear in synchrony with changes to the emitted beam during prey pursuit. We believe that it is the combination of all these dynamic changes, both to the emitted call and to the receiving morphology, that underlie the effectiveness with which bats navigate and forage in the night sky.
Neuronavigated focused ultrasound for clinical bbb opening in Alzheimer’s and brain cancer patients
Authors: Konofagou Elisa
Published: April 2023

Treatment of neurological diseases has been at the forefront of medical research for more than a century with limited success due partly to the blood-brain barrier (BBB) that impedes both delivery and biodistribution of the drug delivered. Focused ulltrasound methodologies in conjunction with systemically administered microbubbles have been shown capable of transcranially and transiently opening the BBB over the past two decades. More recently, those efforts have resulted into clinical translation in a variety of brain diseases such as brain tumors and neurodegenerative disease such as Alzheimer’s (AD) and Parkinson’s disease. Our group has been developing a neuronavigated system for opening the BBB at the patient’s bedside safely and efficiently, i.e., within 20–30 min with real-time cavitation mapping. The findings of two clinical studies are reported herein. In the first clinical study, five AD patients underwent FUS with microbubbles with successful BBB opening in their prefrontal cortex while 60% exhibited amyloid reduction in the sonicated hemisphere. In the second clinical study, four diffuse intrinsic pontine glioma (DIPG) subjects underwent BBB opening similar procedure with successful BBB opening in the pons. An overview of the aforementioned findings together with the most recent clinical outcomes will be presented.
Low frequency ultrasonic absorption in aqueous solutions from variable path through-transmission and pulse-echo measurements
Authors: Lirette Robert , Musiał Małgorzata , Widegren Jason A. , Stelson Angela C.
Published: April 2023

Acoustic absorption spectroscopy can characterize the complex intermolecular interactions within a solution. Currently, there are no wide-spread uses of the method and no commercially available systems exist that measure below 3 MHz. However, chemical processes have been shown to exist at as low as 300 kHz. Here we present measurements on aqueous solutions using two techniques: a variable path through-transmission method operating around 1 MHz and a pulse-echo method operating near 500 kHz. These methods overlap in frequency and their results agreed with each other. We also calibrated the setup using water and measured the sound speed in each sample. Finally, we present preliminary results for the absorption spectra of MgSO4 and other solvents. Accurate measurements of acoustic absorption at low ultrasonic frequencies could prove to be an important tool in the pharmaceutical and chemical manufacturing industries and can lead to better understanding of intermolecular processes in this frequency range.
Ultrasonic characterization and beyond: How to select a hydrogel for tissue engineering
Authors: Anderson Megan S. , Bulusu Kartik V. , Plesniak Michael W. , Zhang Lijie Grace , Sarkar Kausik
Published: April 2023

Hydrogels have emerged as a crucial class of materials within the field of tissue engineering. There is growing interest in matching the mechanical properties of hydrogel scaffolds to tissues in the human body and optimizing these properties for cell growth and differentiation. Gelatin methacrylate (GelMA) is a well-accepted, biocompatible hydrogel with tunable mechanical properties. However, the effects of various formulation parameters on its mechanical properties are not well understood. In this study, an array of GelMA scaffold fabrication parameters is evaluated by varying GelMA concentration and ultraviolet light exposure time. Our overarching goal is to characterize the mechanical properties through ultrasound and rheological measurements, providing a framework for GelMA scaffold selection. Pulse-echo ultrasound techniques were used to non-invasively determine the sound speed and attenuation of the scaffolds, revealing significant dependence on GelMA concentration. Steady shear rate and strain- and frequency-controlled oscillatory shear tests using a rotational rheometer (Model: DHR-2, TA Instruments) revealed a range in the levels of shear-thinning as well as viscoelasticity and showed moduli-dependence on both GelMA concentration and light exposure time. Together, this acoustic and rheological characterization can be used to inform the selection of GelMA scaffolds in tissue engineering applications.
Measuring and evaluating damping in 3D printed multi-material compliant joints
Authors: Lai Heather L. , Yewchuck Bailey
Published: April 2023

Fused deposition modeling (FDM) is a standard 3D printing technique used regularly in high performance and consumer level printers. FDM involves extruding heated thermoplastic filament in multiple layers. When two print heads with dissimilar filaments are used in coordination with one another, alternating print layers, multi-material structures can be designed to exhibit tuned dynamic behavior at the flexible / rigid multi-material interface. Joints tailored with specific stiffness and damping properties have applications in a wide range of fields, including vibration and acoustic isolation. While compliant, flexible materials used in multi-material FDM printing have intrinsic material damping associated with the mechanical energy dissipation within each individual material, additional structural damping resulting from poor material interfaces can also arise in these types of applications. Measurement of this damping can provide a non-destructive means of identifying poor interface joints. Appropriate measurement of both forms of damping are important for tuning compliant joints to the desired dynamic behavior as well as identifying flaws within the interfaces. Several different methods for modeling and measuring damping in multi-material compliant joints will be described, and comparison of experimentally measured damping will be presented for material damping alone, and material damping combined with structural damping resulting from different material interfaces.
Measured noise levels beneath type B flat metal roof assemblies during rainfall
Authors: Mooney Jon W.
Published: April 2023

Flat metal roof assemblies are common in steel building design. Since they can produce high levels of rainfall generated noise, quiet roof assemblies are desirable over noise sensitive spaces. To determine the relative effects of design variations, a pair of fixtures were constructed to measure the noise levels beneath 2 × 4 ft sections of selected roof assemblies subjected to rainfall. Each test item was assembled from precut 2 × 4 ft sections of type B metal roof (with or without a concrete layer), cover boards, and insulation, membrane and ballast as required. The fixtures included a tipping bucket to measure rainfall rate. A microphone located inside each fixture and connected to a digital recorder, picked up ambient noise, rainfall generated roof assembly noise, and the tipping bucket signal. To calibrate the recordings, the sound pressure level of the tipping bucket signal was measured at the recording microphone before testing. Recordings are analyzed to calculate indicated octave band sound power levels versus rainfall rate for the various tested roof assemblies. Promising variations for further study are given.
Computationally efficient deep learning-based image reconstruction for sound speed estimation in ultrasound computed tomography
Authors: Jeong Gangwon , Li Fu , Villa Umberto , Anastasio Mark
Published: April 2023

Ultrasound computed tomography (USCT) has great potential for breast cancer imaging due to its ability to quantify acoustic tissue properties such as the speed of sound (SOS). Full-waveform inversion (FWI)-based image reconstruction methods can produce high spatial resolution SOS images, but these methods are computationally demanding, especially when formulated in the time-domain. Deep learning (DL)-based methods can be computationally efficient and provide high-quality object estimates as studied in various medical image reconstruction problems. However, there remains a further need to develop and assess the DL-based image reconstruction methods for USCT for use in medical imaging applications. Here, we present a supervised DL approach for USCT image reconstruction that is formulated as an image-to-image translation problem. Specifically, a low-resolution SOS image obtained via traveltime tomography and a high-resolution reflection tomography image are used as inputs to a U-Net, which is trained to estimate a high-resolution SOS map. These input images are complementary, providing both quantitative information about SOS values and information about tissue boundaries. Numerical studies that employ realistic numerical breast phantoms demonstrated that the proposed method produced high-quality SOS estimates based on image quality metrics such as NMSE, SSIM, and PSNR.
Development and evaluation of primary calibration methods in underwater acoustics in a frequency range from 1 Hz to 100 Hz
Authors: Biber Alper , Corakci Ata C.
Published: April 2023

The project entitled “Metrology for Low Frequency Sound and Vibration” (“INFRA-AUV”), currently active within the European Metrology Programme for Innovation and Research (EMPIR). Measurement of seismic and infrasound activity is very important for monitoring natural extreme events. Low frequency sound and vibration monitoring technologies are well-established, but the sensors are often used for specific and local applications only and lack traceability. This project aims to establish both the first primary measurement standards for low frequency sound (in both air and water) and vibration. The aim of the task “Development and Evaluation of Primary Calibration Methods in Underwater Acoustics in a Frequency Range from 0.5 Hz to 100 Hz” is to develop and evaluate candidate calibration techniques in underwater acoustics for use as primary standards in frequency range of interest. These methods will be evaluated in terms of their limitations, uncertainty contributions and calibration results. The pressure coupler reciprocity method is based on the hydrophone, a transducer and projector which are calibrated inside a relatively small coupling chamber where the acoustic field is homogenous. Through a series of electrical measurements of voltage and current, the acoustic sensitivity of the three devices may be calculated traceable to electrical primary units.
Shear wave elastography: From dispersion matching to full waveform inversion
Authors: Guddati Murthy , Roy Tuhin , Elmeliegy Abdelrahman M. , Urban Matthew W.
Published: April 2023

Shear Wave Elastography (SWE) involves estimating mechanical properties through inversion, i.e., matching measured and simulated propagation characteristics of shear waves in the tissue. The accuracy of the estimated properties depends significantly on the specific characteristics/responses that are being matched. These could range from simple group velocity to dispersion curves and to full-wave response (particle velocity measurements). Using specific applications of arterial, liver, and tumor elstography, we illustrate that effective SWE is performed by resorting to an inversion approach, or combination of inversion approaches, guided by the underlying physics. To this end, we present inversion approaches ranging from matching dispersion characteristics to matching full waveform responses and provide rationale for choosing the appropriate technique(s) depending on the problem at hand.
Time-resolved passive cavitation mapping using the transient angular spectrum approach
Authors: Jing Yun , Li Mucong , Gu Juanjuan , Zhong Pei , Yao Junjie
Published: April 2023

Passive cavitation mapping (PCM), which generates images using bubble acoustic emission signals, has been increasingly used for monitoring and guiding focused ultrasound surgery. This study investigates a transient angular spectrum (AS) approach for PCM. The working principle of this approach is to backpropagate the received signal to the domain of interest and reconstruct the spatial–temporal wavefield encoded with the bubble location and collapse time. The transient AS approach is validated using an in silico model, water bath, and in vivo experiments. It is found that the transient AS approach yields similar results to delay and sum, but is considerably faster. The results obtained by this study suggest that the transient AS approach is promising for fast and accurate PCM.
Addressing blank stares and unintended paths in student-centered learning
Authors: Nelson Jill K.
Published: April 2023

Despite decades of research supporting their effectiveness, adoption of student-centered teaching practices is slow, and many instructors try active learning only a few times before reverting to traditional teaching methods. Like most skills, learning to design and facilitate student-centered activities takes practice, and new adopters often encounter frustrations as they begin to implement these approaches. Sharing best practices for smoothing the implementation of active learning can increase the likelihood that instructors will adopt and sustain evidence-based practices. I will describe two common hurdles (and how I address them) when implementing student-centered activities in my undergraduate signals and systems courses. (1) The blank stare: Whether it be resistance to active learning practices, lack of understanding of the content, or just not enough sleep the night before, students often struggle to get started when handed an active learning activity. (2) The path not intended: One of my favorite parts of teaching is designing activities that (I believe) are engaging, relevant, and help students draw connections among important concepts. More often than I’d like to admit, however, the approach I have in mind when designing the activity bears little resemblance to the (equally valid) approach students take when completing it.
When a simple demonstration of resonance in a forced oscillation system proved that resonance does not exist
Authors: Linz Jill A.
Published: April 2023

Students in an introductory musical acoustics course attempted to recreate a simple forced oscillation system to verify its resonant frequency. The procedure followed ideas and instructions found in a YouTube video from Animated Science to show resonance. This was tested by the instructor prior to the experiment, who found it to be straightforward to assemble and to make the appropriate measurements. The calculated frequency was found to be within 2.5% of the experimental value. The students were given two identical springs, each with a spring constant of 30 N/m and a 100 g mass, as well as a function generator and apparatus needed to connect the system. The video shows the mass suspended between the two springs with one end driven by a function generator while the other end is fixed. A meterstick was placed behind the mass spring system to get a rough estimate of the peak amplitude. 6 separate groups of 3 students each tried to assemble the system as shown. Not a single set-up worked as it did in the video. The reasons for this were as varied as the number of groups doing the experiment. The experiment was refined over several years into a well-executed experiment.
Quantifying the effect of flanking sound transmission on sound insulation and speech privacy metrics
Authors: Mackenzie Roderick
Published: April 2023

In modern commercial office design, sustainable building codes and quality standards often demand certain levels of sound insulation to ensure sufficient speech privacy or freedom from distraction for the occupants. Missing from the minimum requirements of these documents, however, is guidance on eliminating flanking weaknesses that repeatedly and significantly degrade the experienced speech privacy. This paper presents case studies of common acoustical weaknesses found between closed offices and meeting rooms. Through the use of sound intensity measurements and acoustical imagery, the sound power of each weakness is calculated and shown relative to the sound power of the separating partition. By comparing these results to partitions without these weaknesses, the effective reduction in speech privacy is demonstrated using the ASTC, NIC, and SPC metrics. Weaknesses examined and ranked include, open ceiling plenums, lack of or ineffective door seals, door closure pressure, continuous door frames, façade mullions and transoms, interior windows and their frames, lack of acoustical sealant, uninterrupted gypsum on side walls, common door frames at the edges of partitions, modular and operable walls and their junctions, continuous heating elements, thin continuous floor toppings, and ventilation duct crosstalk.
Blowing out a candle from a distance with high amplitude time reversal
Authors: Clift Jay M. , Patchett Brian D. , Anderson Brian E.
Published: April 2023

Time reversal is a technique that allows the focusing of sound from a source to a remote location causing an impulsive focusing event. Using more sources and other amplitude-increasing techniques, the focusing of audible sound can reach over 200 dB peak. This can extinguish the flame on a single candle without affecting nearby lit candles. Most methods used to extinguish a flame using sound involve the nearfield and nonlinear airflow effects. Because time reversal focusing can occur far from the sources, the mechanism is different. Using high-speed video footage of the focal event, we can see the finer details of this millisecond scale focus interacting with the flame. Measuring the sound field during the focus event at and near the focal location also sheds light on the mechanism. So far, it has been seen that the focus pushes the flame outward, separating the plasma from its fuel source. The known formation of shock waves provides a possible explanation. Further research is being done to explore the cause of the extinguishing of the flame. This talk will show that not only is it possible to focus high amplitude sound waves but targeted flows of air as well.
Modeling free space Mach stem formation in high-amplitude focusing of sound using time reversal
Authors: Patchett Brian D. , Anderson Brian E. , Kingsley Adam D.
Published: April 2023

In acoustics, time reversal processing may be used to focus sound to a selected spatial location. Recently, the nonlinear characteristics of time-reversalfocusing at amplitudes as high as 200 dB have been reported [Patchett and Anderson, J. Acoust. Soc. Am., 151(6), (2022)]. These studies were experimental in nature and suggested that converging waves nonlinearly interact in the focusing of waves, leading to surprising observations of nonlinear amplification. This study investigates the nonlinear interactions and subsequent characteristics from a model-based approach. Utilizing both the k-Wave© package for MATLAB©, and COMSOL Multiphysics©, it is shown that nonlinear interactions between high-amplitude waves leads to free-space Mach-wave coalescence of the converging waves. The number of waves used in both models represents a small piece of the full aperture of converging waves experimentally. Limiting the number of waves limits the number of Mach-stem formations and reduces the nonlinear growth of thefocus amplitudes when compared to experiment. However, limiting the number of waves allows the identification of individual Mach waves. Mach wave coalescence leading to Mach-stem formation appears to be the mechanism behind nonlinear amplification of peak focus amplitudes observed in high amplitude time reversal focusing.
Noise characterization of unmanned ground vehicles for infrasound array deployment
Authors: Kinnebrew James , McComas Sarah
Published: April 2023

Deployment of infrasound arrays can present humans with challenges including harsh environments and dangerous chemicals. Infrasonic monitoring is the use of subaudible acoustics to monitor something of interest. Sources of infrasound include natural and manmade sources such as volcanic eruptions, large forest fires, and explosions. Robotic infrasound array deployment is being investigated to mitigate the potential challenges associated with human deployment. Robotic deployment would also allow for remote sensor repositioning to improve array response for specific sources. Unfortunately, robotic sensor emplacement will induce noise associated with the robotic platform, and this noise has a potential to mask sources of interest under certain conditions. Understanding to which conditions robotic deployment is applicable is vital to exploring infrasonic monitoring in hazardous environments in the future. This presentation will describe the characterization of noise generated by multiple robotic platforms in both mobile and stationary states. Analysis during each of these states allows for the determination of when robotic mounted infrasonic monitoring is viable.
Perception of emotional music by children with cochlear implants reveals developmental plasticity
Authors: Gordon Karen A.
Published: April 2023

Cochlear implants provide poor access to the frequency components needed to accurately identify emotional music and speech. Nonetheless, a series of studies revealed that children with cochlear implants develop unique strategies to identify emotion in music. Although musical changes were difficult for them to detect, children with cochlear implants responded most accurately to rhythmic changes and also relied mainly on temporal information to judge whether music was happy or sad. By contrast, mode (frequency) information dominated perception of musical emotion in typically developing children and was used more clearly by bimodal device users (cochlear implant in one ear with acoustic hearing in the other) than children with bilateral deafness using unilateral or bilateral cochlear implants. Mode became the more dominant cue with increasing residual hearing in the non-implanted ear. Children with unilateral cochlear implants showed prolonged response times relative to a control group of normal hearing peers while judging whether music was happy or sad. Response times in children with bimodal devices and bilateral cochlear implants were more similar to controls. Together, these results demonstrate development of novel strategies for music listening and perception of emotion in music based on available cues in children with cochlear implants and suggest that these strategies require cognitive resource.
Orthographic information facilitates discrimination of native and foreign-accented speech
Authors: Sevich Victoria , Clausing Emily M. , Moberly Aaron C. , Tamati Terrin N.
Published: April 2023

Previous research on the perception of foreign-accented speech has demonstrated that providing orthographic transcriptions of auditory stimulus words influences accentedness ratings of the talker. Specifically, foreign-accented talkers are rated as having less accented speech in favorable listening conditions when orthographic information is present. Cochlear implant users show poor identification and discrimination of foreign-accented speech relative to listeners with normal hearing. In the current study, we examined whether orthographic information facilitates the discrimination of native and foreign-accented (non-native) speech under cochlear-implant simulation. Participants were presented with native or foreign-accented sentences through an eight-channel noise vocoder with or without matching text. They were asked to determine whether the sentence was spoken by a native or non-native talker. We hypothesized that the presence of matching text would increase identification accuracy and decrease reaction time. Consistent with our predictions, participants more accurately and more quickly identified whether sentences were spoken by a non-native talker in the presence of matching text compared to performance in conditions with no text. These results suggest that the presence of orthographic information may facilitate indexical, non-linguistic perception under cochlear-implant simulation. Future work will determine whether these results may extend to cochlear implant users.
Arousal but not valence: Music emotion categorization in normal hearing and cochlear implanted participants
Authors: Harding Eleanor , Gaudrain Etienne , Hrycyk Imke , Harris Robert , Tillmann Barbara , Maat Bert , Free Rolien , Başkent Deniz
Published: April 2023

Perceiving acoustic cues that convey music emotion is challenging for cochlear implant (CI) users. Emotional arousal (stimulating/relaxing) can be conveyed by temporal cues such as tempo, while emotional valence (positive/negative) can be conveyed by spectral information salient to pitch and harmony. It is however unclear the extent to which other temporal and spectral features convey emotional arousal and valence in music, respectively. In 23 normal-hearing participants, we varied the quality of temporal and spectral content using vocoders during a music emotion categorization task—musical excerpts conveyed joy (high arousal high valence), fear (high arousal low valence), serenity (low arousal high valence), and sorrow (low arousal low valence). Vocoder carriers (sinewave/noise) primarily modulated temporal information, and filter orders (low/high) primarily modulated spectral information. Improvement of temporal- (using sinewave carriers) and spectral content (using high filter order) both improved categorization. Vocoder results were compared to data from 25 CI users performing the same task with non-vocoded musical excerpts. The CI user data showed a similar pattern of errors as observed for the vocoded conditions in normal-hearing participants, suggesting that increasing the quality of temporal information, and not only spectral details, could prove beneficial for CI users’ music emotion perception.
Investigation of the radiated sound energy from noise sources using an indirect vibration-based sound power approach
Authors: Bacon Ian C. , Jensen Naomi M. , Sommerfeldt Scott D. , Blotter Jonathan D.
Published: April 2023

An indirect vibration-based sound power (I-VBSP) method is being developed for acoustic sources radiating energy that cannot be captured using surface vibration measurements. This method involves placing this type of source into a small enclosure that has a single flexible side which the noise source will excite. The vibration-induced side can then be scanned using a scanning laser Doppler vibrometer (SLDV) and calibrated to obtain the free-field energy of each source. Several challenges have been identified during the development of this method, many of which have been addressed to improve the accuracy of calibrating out the effects of the enclosure on the radiation from these noise sources and improve the SLDV measurements. A box-in-box structure was fabricated with a flexible panel to investigate the acoustic response of this new enclosure versus the previous mylar membrane enclosure. Results for the sound power of a source obtained through the mylar and panel structures using the I-VBSP method will be compared with the free-field sound power of the source determined in a reverberation chamber using the ISO 3741 standard. [Funding for this work was provided by the National Science Foundation (NSF).]
Modal testing on a limited budget: Analysis of instrumented hammer alternatives for impact testing
Authors: Hall Hubert S. , Larsen Curtis
Published: April 2023

In recent years, as the use of numerical modeling has increased, organizations have frequently scaled back their experimental capabilities. Often equipment and expertise are no longer available when modal correlation measurements are required. This presentation is part of a planned series examining a minimalist approach to modal testing. In this presentation, alternatives to a traditional instrumented hammer for impact testing are explored. Comparison testing between a dedicated instrumented hammer procured from a leading structural measurement company and commercial hammers acquired from a hardware store was performed. Two cases of commercial hammers were studied, one featuring a force gauge inserted into the impact hammer face and one with an accelerometer attached to the hammer body. A variety of hammer tips were explored for focused frequency content. Follow-on topics include rudimentary data acquisition options and methods of modal data analysis outside of expensive dedicated modal analysis software platforms.
Mechanical characterization of additively manufactured polymers using ultrasonic nondestructive testing
Authors: Nivarthi Akash , Haberman Michael R. , Naify Christina
Published: April 2023

Ultrasonic nondestructive testing (NDT) can be used to relate the print settings of additively manufactured polymers to their macroscopic elastic properties. We present a comparison of the measurement of angle- and frequency-dependent ultrasonic transmission through a flat plate to predictions using a multiscale model that considers infill geometry and constitutive material properties. The experiment is an immersion test that uses a point source and synthetic linear array to measure the transmission coefficient from 0.2 to 1 MHz over a wide range of incident angles. Samples were fabricated using fused deposition modeling (FDM) to print infilled plates with polylactic acid (PLA) filament. Transmission measurements were compared to predictions from a multiscale model consisting of a finite element model to predict the effective anisotropic stiffness based on an assumed infill geometry and PLA material properties and an acoustic reflection-transmission model for an anisotropic elastic plate submerged in water based on the work of Rokhlin and Wang [J. Acoust. Soc. Am. 112, 822 (2002)]. Minimization of the difference between the measured and modeled transmission coefficient for all angles and frequencies by varying model inputs provides an improved understanding of the effects of the print settings on the as-built mechanical properties for 3D-printed materials.
Emphasis spread in Arabic: The domain and trigger
Authors: Jaber Aziz
Published: April 2023

Acoustic coarticulatory effects of emphasis, a secondary articulation in the posterior vocal tract simultaneously accompanying a primary one, were investigated in Urban Jordanian Arabic. Nine native speakers of the dialect were recorded reading tri-syllabic monomorphemic and bimorphemic minimal pairs. The minimal pairs contained the voiceless emphatic fricative /sʕ/ and its plain counterpart /s/ in word initial and word final contexts. The acoustic correlates of emphasis include a raised F1, lowered F2, and raised F3 in the vowels preceding and following the emphatic sound. The results have roughly corroborated our findings in the previous research that the morpheme is, though disproportionately, still a confounding factor of emphasis spread. The most interesting contribution of this research is the perplexing behavior of emphasis spreading when crossing over the morpheme boundaries. Whereas the influence of the emphatic sound is evident on the morpheme falling to its left (e.g., prefixes) is evident, its influence of the morpheme falling to its right (i.e., suffixes) is less clear. This amounts to saying that the morpheme boundary between the stem and the suffix is stronger than that between the stem and the prefix. What this means is that a line of demarcation should be drawn between suffix boundary and prefix boundary.
Speech directivity patterns generated from a high-fidelity speech corpus
Authors: Trine Allison , Miller Margaret , Buss Emily , Stecker G Christopher , Monson Brian B.
Published: April 2023

Human talkers are directional sound sources—a phenomenon that has consequences for speech perception in multi-talker environments. Directivity patterns for speech showing frequency- and angle-dependent radiation reveal that speech generally becomes more directional toward the front of the talker as frequency increases. Differences in physical attributes can lead to individual variability in directivity patterns across talkers. Here, we examine individual variability in speech directivity using frequency-dependentdirectivity indices and directivity maps. Speech directivity was examined in the horizontal plane using a corpus of simultaneous multi-channelfull-bandwidth (48-kHz sampling rate) recordings of the Bamford-Kowal-Bench (BKB) sentences recorded in an anechoic chamber. Thirty subjects (15 female) were recorded. The long-term average speech spectrum was utilized to calculate directivity indices in 1-ERB (equivalent rectangular bandwidth) bands. Gender differences in directivity indices were evaluated using a linear mixed-effects model. There was no main effect of gender. There was a main effect of ERB band with higher-frequency bands tending to have higher (i.e., more directional) directivity indices, however there was a nonmonotonic relationship between average directivity indices and frequency. Directivity maps demonstrated individual differences in speech radiation. [Work supported by NIH under Grant No. R01-DC019745.]
Categoricity and gradience: A case study of Sakha lateral liquids
Authors: Munshi Hassan
Published: April 2023

I report on a recent acoustic study on the lateral liquid /l/ variation in Sakha (Turkic). I investigated /l/ darkening in Sakha in multiple lexical (including mono- and bi-morphemic) environments. In particular, I show that the effects of neighboring vowels on /l/ darkening are quite remarkable, to the extent that one is tempted to conclude that /l/ is participating in vowel harmony. I do not necessarily make this claim, but it is quite clear that adjacent vowels play a major role in Sakha/l/ darkening. The results show that /l/ variation in this language, like English, is both categorical and gradient. Backness of vowels determines which /l/ to appear. Therefore, the major finding of the study is that, rather than syllable structure, it is primarily vowel backness that determines /l/ variation in this language. This, in turn, indicates that variation of this consonant is categorically affected by vowel harmony. At the same time, I also discuss how one could potentially argue for a completely phonetic (i.e., gradience) approach. Still, based on the investigation of /l/ variation in several environments, I conclude that categoricity and gradience each plays a distinct role.
Acoustic speech parameter relationships with voice disorders and phrase differences
Authors: Ramani Sai Aishwarya , Hunter Eric J. , Cantor Cutiva Lady Catherine
Published: April 2023

While acoustic speech analysis is non-invasive, the utility has been mixed due to the range of voice types. For vocal health practitioners to efficiently and quickly assess and document voice changes, knowing which voice parameter would be sensitive to vocal change is crucial. Using a database of 296 individual voices including 8 voice pathology types and typical voice samples, the sensitivity of a range of acoustic speech parameters to differentiate common voice pathology types was investigated. Both traditional and contemporary acoustic speech metrics were estimated for the samples using a custom MATLAB script and PRAAT (e.g., jitter, shimmer HNR, CPPS, Alpha ratio, PPE). Analysis then evaluate the predictability value of the metrics to discriminate pathology type. From the pool of parameters, 11 were able to identify pathological voices from normal controls and several of the parameters were more sensitive to some pathology. For example, CPPs and jitter values could discriminate neuropathological voices whereas HNR and Shimmer cold discriminate muscle-based pathologies. These results indicate how the sensitivity of acoustic speech metrics to the voice pathology types can allow for the identification of individual metrics (or combinations of metrics) which could be used to track changes in vocal health.
Acoustical analysis of Taylor Swift’s speech and singing throughout her career
Authors: Mohamed Miski A. , Winn Matthew B.
Published: April 2023

Taylor Swift has changed geographic environments, speaking communities, and singing communities throughout her career, inviting question into changes in her voice acoustics. Capitalizing on the availability of interviews and multiple song recordings, we tracked changes in vowel formant trajectories and other vocal properties from different points in her life to see how her voice might have been influenced by these changes in community (e.g switching from country to pop style, moving from Philadelphia to Nashville). Comparing vowel space from 2012 to 2019, we observe higher tongue position (lower frequency F1) for numerous vowels, especially for /eɪ/ and /aʊ/. Rounding for /ɔ/ was reduced, and /æ/ was pronounced farther back in the mouth. We also observed reduced distinction between the varieties of /ɑɪ/ before voiced and voiceless consonants (e.g., ride versus write), as well as greater front-back movement for /u/. Studio re-recordings show remarkable consistency of word timing and intensity. Conversely, Swift’s live singing voice includes some variation from the recording, including fewer silences between words. Live versions feature extended duration for words that are emphasized for emotion, and/or ends of phrases, compensated by shorter durations for other segments so that the overall song length was very consistent.
Acoustic correlates of aspirated consonants in Maranao
Authors: Lobel Jason W. , Thomas Erik R. , Mielke Jeff , Riwarung Labi H.
Published: April 2023

Aspirated obstruents are rare in Austronesian languages, one exception being the southern Philippine language Maranao, as reported by Lobel and Riwarung [Oceanic Linguist. 48, 403–438 (2009)]. In Maranao, aspirated consonants occur as a reflex of a cluster of a former voiced stop and a homorganic obstruent (*bp > p’, *dt > t’, *ds > s’, *gk> k ’). The most obvious correlate to non-Maranao speakers is a dramatic raising of the following vowel, which also occurs after voiced obstruents, but not after historic single voiceless obstruents—e.g., /təkaw/ [təkaw] ‘startled’ (earlier *təkaw) vs. /tək’aw/ [təkʰɣw] ‘thief’ (earlier *təɡkaw) However, native Maranao speakers regard the raising as a property of the consonants, not the vowels. We examined the correlates of the apparent aspiration. The vowel raising is realized robustly and consistently, with some overlap in F1/F2 space among contrastive vowels. However, aspirated and unaspirated stops also show differences in VOT and in measures of breathiness of the following vowel, albeit with somewhat less consistency. Differences between /s/ and /s’/ were not evident except for realizations of following vowels. We explore the role of pharyngeal expansion due to voicing in the development of these Maranao segmental realizations.
Numerical modeling of the 2D hologram of the low-frequency moving source by using horizontal antenna in a shallow water waveguide
Authors: Pereselkov Sergey A. , Kuz'kin Venedikt , Tkachenko Sergey , Ladykin Nikolai , Sotnikov Dmitry
Published: April 2023

The 2D holographic signal processing method by using a horizontal linear antenna (HLA) in shallow water is considered in the paper. The offered method of moving broad band source sound field hologram formation by using HLA is based on holographic signal processing of each element of HLA. The sound source moving in shallow water waveguide creates a stable interference pattern (interferogram) in the frequency-time domain on each HLA element. The 2D-FT (2D Fourier Transformation) of the interferogram is antenna element hologram (AEH). AEH allows to coherently accumulate the sound intensity of the interferogram in a small area as focal spots for each HLA element. It is shown in paper that the focal spots localization in AEH of HLA depends upon the source range, velocity, and motion direction [S. Pereselkov and V. Kuz’kin, JASA 151(2), 666–676). The output HLA hologram is formed by superposition AEH. Relationship between focal spot coordinates on the HLA hologram and the source range, velocity, and motion direction are derived in the paper. The results of the numerical experiment of HLA hologram formation for low-frequency (100–400 Hz) sound field of source moving in shallow water are presented. The results presented in the paper significantly expand the efficiency of interferometric signal processing in shallow water. [This study was supported by RFBR 19-29-06075, МК-4846.2022.4.]
Maximum likelihood estimation for leak localization in water distribution networks using in-pipe acoustic sensing
Authors: Agrawal Pranav , Fong Stan , Friesen Dirk , Narasimhan Sriram
Published: April 2023

With drinking water resources rapidly depleting with time, water conservation efforts have received special emphasis, especially in arid regions like California. One of the major sources of unused water expenditure is inconspicuous leaks in underground water distribution networks (WDN), making it highly essential to quickly detect and localize them. The leak detection and localization problem has been widely studied for a straight pipeline system, however, estimating the leak location in a pipe network remains largely unexplored. In this study, we measure the acoustic pressure signals inside a pipe network at multiple locations using state-of-the-art hydrophone-enabled devices. To localize the leaks in pipe networks, we propose maximum likelihood estimation, which has previously shown high efficacy in localizing mobile devices in a cellular network. In this approach, the cross-correlation of the filtered signals from different sensor pairs yields multiple time delays corresponding to multiple acoustic paths traversed by the leak noise in the pipe network, which is more difficult to solve compared to a straight pipe system. The leak location is then identified by maximizing a conditional probability distribution function of the distance between the sensor and the leak location.