bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of contribution degree of vibration transmission of bolted structure
Authors: Liu Shuai
Published: November 2023

In practical engineering, the vibration transmission between bolted structures supported by cantilever beams involves many factors. The vibration transmission effect is the embodiment of the coupling of various factors, so it is impossible to accurately and quantitatively evaluate the influence degree of various factors. In this paper, the influence factors of vibration between bolted plates in the form of cantilever beam are studied by numerical calculation method. The effects of friction coefficient, bolt preload, temperature and pressure on vibration characteristics are studied. Finally, the contribution of different influencing factors to vibration transmission is given.
An quantitative analysis of Punjabi tones
Authors: Nara Kiranpreet
Published: November 2023

Punjabi has three tones, the falling and the rising tones developed due to the historically lost voiced aspirated consonants and word-final glottal fricative /ɦ/, and the default tone occurred elsewhere. While there has been some experimental research on Punjabi tones, there have been limitations due few stimuli and speakers. The main aim of the current study was to provide a phonetic examination of the fundamental frequency (f0) patterns across a large number of Punjabi words produced by multiple speakers. The experiment was conducted online using 24 native speakers (9F, 15M) of Indian Punjabi. The list of stimuli contained 66 monosyllabic words (default = 18, falling = 15, rising = 33) with either /a/ or /ə/. The speakers were recorded producing the stimuli in carrier and natural sentence environments. Linear mixed effects analyses were conducted on six f0 measures: the onset, mid, and offset of the vowel, the f0 range (MaxF0-MinF0), and the f0 trajectory in the first (MidF0-BegF0) and final (EndF0-MidF0) halves of the vowel. The results confirmed three distinct pitch curves for the three tones. Each of the three tones were distinguished from one another for the onset f0 and the EndF0-MidF0 measures. Vowel quality influenced tone realization. Between-speaker and word variation was observed.
Expanding research on ʔayʔaǰuθəm interrogative intonation
Authors: Schnoor Tyler T. , McCarthy Mary A.
Published: November 2023

Relatively little research has been done on ʔayʔaǰuθəm prosody. This lack of research is due in part to the idea that stress and tone are not distinctive features in the language. However, recent studies have found evidence of suprasegmental features in ʔayʔaǰuθəm interrogatives. Additionally, previous work indicates that—as has been reported with other Salishan languages—there is no significant rise in fundamental frequency at the end of ʔayʔaǰuθəm interrogatives, though the mean vowel fundamental frequency is higher in interrogative than in declarative sentences. These findings are not unique to ʔayʔaǰuθəm, but they do contribute to growing evidence that a final rise in fundamental frequency in interrogative sentences is not universal. In the present study, we aim to address the limitations of our previous work by expanding on the amount of data used, incorporating methods for analyzing the entire fundamental frequency contour, and measuring the mean fundamental frequency of vowels from more balanced stimuli. Although we do not expect different results from the present study, it is our hope that the methodologies used will increase the validity of our findings on ʔayʔaǰuθəm interrogative intonation.
Application of trans-dimensional particle filtering for geoacustic inversion
Authors: Wu Weiwen , Ren Qunyan , Ma Li
Published: November 2023

The acquiring geoacoustic model and associated geoacoustic parameters is vital for sound propagation modelling in a range-dependent environment. Conventional sequential methods, e.g., particle filtering and Kalman filtering have been widely used for geoacoustic inversion in range-dependent environment, which encounter challenges when confronted with unknown geoacoustic models that intrinsically varying with range. As an attempt to estimate geoacoustic model and associated geoacoustic parameters as well, a trans-dimensional particle filtering method is presented here. This method integrates birth-death rules into the filtering process, enabling automatic selection of appropriate geoacoustic models and estimating geoacoustic parameters in the same time. Numerical simulations were conducted based on an environment model of the South China Sea, where a sea trial was conducted in 2022. Numerical results demonstrate the efficiency in accurately estimating the geoacoustic model variations and associated parameters. Preliminary results of sea trial data processing are also presented here.
Retroreflective room acoustics: Possible treatments, their effects, and potential benefits
Authors: Lu Shuai , Cabrera Densil , Holmes Jonothan
Published: November 2023

Introducing retroreflection into rooms can change the distribution of reflected energy, concentrating early reflections on the source. But what is a retroreflective room, and how could it be implemented? This paper introduces concepts including retroreflective arrays andretroreflective focusing, which achieve much more than the trivial case of a rectangular room. Examples are developed via finite-differencetime-domain simulation. Treatment strategies include making use of the room corners and edges as focusing retroreflectors, retroreflective ceiling treatments, and using local retroreflective treatments such as desk reflectors. The acoustic features of the retroreflective rooms are compared with design targets of open-plan offices, classrooms and restaurants, to illustrate potential benefits of retroreflective treatment of rooms for speech.
Experimental characterization of scattered reflections of sound diffusers using a portable high-resolution acoustic goniometer
Authors: Xiang Ning , Chen Ziqi
Published: November 2023

Surface scattering and diffuse reflections from acoustic diffusers have recently become a significant topic of research for room acoustics. An acoustical goniometer can be implemented in the form of a circular microphone array to characterize scattered responses for various types of diffusing elements/devices. This research is also intended for experimental validation of diffraction simulations of finite-sized diffusing devices using the physical theory of diffraction (PTD). To cope with experimental challenges, an acoustic goniometer must achieve a fine enough angular resolution in addition to fulfilling far-field requirements. This paper will discuss pragmatic implementations and experimental results of portable goniometers with a radius of up to five meters and an angular resolution of 1.25 degrees. The pragmatic implementation is intended to be easily deployable in empty, indoor spaces of sufficiently large dimensions for scattered reflection characterization. This paper highlights an effort of increasing experimental efficiency of measurement routines for oblique incident characterization and challenges of characterizing full angular ranges of scattered reflections.
Limitations of the scattering coefficient for simulating early reflections
Authors: Feistel Stefan , Vorlaender Michael , Olson Bruce C.
Published: November 2023

The introduction of the scattering coefficient has enabled geometrically-based acoustic simulations to produce full-length impulse responses of fairly high accuracy. However, the scattering coefficient is a random-incidence quantity that can be applied only when considering a statistical energy average over different directions. This model is inaccurate if a single reflection by a surface element is considered for which the scattered part of the sound energy depends strongly on the angle of incidence. The resulting deviation can be particularly relevant for first-order reflections as these reflections have significant influence on acoustic parameters that make use of early-energy estimates, such as D, C80 or LF. In this paper, the uncertainty of the specularly reflected energy is estimated and discussed for a number of typical surface structures and scenarios. The corresponding impact on the accuracy of predicted early-energy parameters is also discussed. Possible solutions and extensions such as an angle-dependent scattering model are outlined.
Challenges in the use of architectural concrete for sound diffusion—A case of 350 seats concert hall in Poland
Authors: Klosak Andrzej , Gade Anders C.
Published: November 2023

This paper discusses the design, realization and acoustical performance of a recently opened 350 seats music school concert hall, located in Jastrzębie Zdrój, Poland. Several design aspects are discussed: restrictions due to cost optimization in material selection, geometrical design of “wavy” reinforced concrete walls and acoustical performance of the finished auditorium. Construction details of the interior surfaces their influence on the acoustics are also discussed.
Using behavioural response experiments to measure humpback whale hearing in noise
Authors: Dunlop Rebecca , Noad Michael , Houser Dorian
Published: November 2023

Currently, there are no direct data on mysticete hearing in noise. Available data comes from anatomical modelling, the assumption they can hear their own sounds, and studies on the effects of various sources of anthropogenic noise on their behavior. This study used a behavioral response study design to quantify humpback whale hearing in natural ocean noise. Tonal signals, ranging from 250 Hz to 16kHz, were used as the stimuli, and a change in humpback group behavior indicated the whales heard the signal. Individual whale and group behavior were quantified using a combination of land-based tracking data of groups and tag data deployed on individual whales to record fine-scale 3D movement underwater. The signal-to-noise ratio was estimated at the initial response position of the group or whale, assuming this was the level at which they first detected the tone in noise. Results confirm that humpback whales responded to signals in noise at detection levels comparable to other marine mammals and that their ability to hear signals in noise at higher frequencies is better than expected. This provides empirical data on hearing in a mysticete which can be used to better predict the acoustic impacts of anthropogenic noise on marine mammals.
Acoustic behaviour in bottlenose dolphins during two different target discrimination tasks
Authors: Torres Ortiz Sara , Hernandez Sanchez Ariana , Jakobsen Freja , Almunia Javier , Wahlberg Magnus
Published: November 2023

Echolocation is an active sensory system that gives an acoustic representation of the surroundings by the animal emitting clicks, detecting and analysing echoes. However, little is known about dolphin biosonar in moving animals, as well as of the process of controlling click emissions, and the cues used by the animal to discriminate between different targets. We studied how bottlenose dolphins may use their dynamic sound production and hearing abilities, along with head and body movements, to detect and classify objects through echolocation. We designed two different experiments with blindfolded bottlenose dolphins (Tursiups truncatus) swimming freely along the pool and actively discriminating between two targets of three different materials, and a second one to determine the capability to discriminate wall thickness differences in cylindrical targets of the same material. By means of synchronized cameras and hydrophones, we observed clear differences between individuals of the same species in terms of ability to discriminate, but similar performance with the harbor porpoises in relation to the materials chosen with the difficulty of the task. Studying how the dolphins solved a simplified echolocation task, allow a better understanding of the processes behind target detection and discrimination capabilities during natural biosonar circumstances .
Revisiting acoustic detections made in the Indian Ocean at the time of the loss of MH370
Authors: Dall'Osto David R. , Duncan Alec J.
Published: November 2023

After an expansive multi-year undersea search, the whereabouts of airliner MH370 remains unknown. Given the energetics the crash, and the evidence (e.g., debris) that it crashed somewhere out in the open Indian Ocean, it is possible that MH370 made a detectable noise. Coincidently, as stated in the final Australian Transportation and Safety Board (ATSB) report, there was “An acoustic signature at the time of the final transmission from the engines, but which is at odds with the location determined by the satellite analysis.” Following the years-long unsuccessful search, and in light of the acoustic detection of the crash of a Japanese F35 fighter jet in 2019 (received at a similar hydroacoustic station located in the Central Pacific), it seems timely to review the acoustic data to re-assess the likelihood that it is related to the loss of MH370. If the hydroacoustic evidence were included, then the probable crash area would shift significantly to a site roughly 750 km west of the Maldives.
Mapping acoustic properties of tissues at low temperatures for ultrasound rewarming
Authors: Liang Suzi , E. Treeby Bradley , Martin Eleanor
Published: November 2023

Cryopreservation of large volumes of cells and tissues, followed by successful rewarming, promises to revolutionize organ transplantation by extending organ preservation times. This technology addresses a critical issue: over 6,000 individuals in the UK are awaiting organ transplants, yet an alarming 60% of donated organs go unused due to current preservation time limitations. A significant challenge lies in providing a rapid and uniform rewarming method for cryopreserved tissues. Ultrasound, capable of converting sound power into heat as it propagates through tissue, offers a promising solution. Nonetheless, before tapping into ultrasound’s potential for rewarming experiments, a fundamental understanding of the acoustic properties of tissues, which vary with temperature and during phase change, is essential. This study employs the multiple-reflection method (MRM), with buffer-rod positioned between the transducer and sample, to measure the acoustic attenuation coefficient and sound speed in biological relevant materials and the primary components of tissues, such as water and lipids, across a temperature range of 20 to −100ºC. Concurrently, the acoustic properties of commonly used cryopreservation solutions were assessed. These data will facilitate computational simulation of acoustic power delivery and the resulting temperature distributions, enabling planning and monitoring of tissue rewarming, which is critical to its success.
Noninvasive material characterization of biomaterials: Measuring viscosity and elasticity using ultrasound
Authors: Anderson Megan , Bulusu Kartik , Plesniak Michael , Zhang Lijie Grace , Sarkar Kausik
Published: November 2023

The advent of tissue engineering has led to increased interest in the viscoelastic characterization of biomaterials. Gelatin Methacrylate (GelMA) is a particularly promising biomaterial, largely due to its tunability, yet the impact of different preparation parameters on the material’s viscoelasticity is not well understood. We characterized an array of GelMA scaffolds, fabricated by varying both GelMA concentration and ultraviolet (UV) lightexposure time. 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 tests in addition to strain- and frequency-controlled oscillatory shear tests were performed using a rotational rheometer (Model: DHR-2, TA Instruments) to ascertain the levels of shear-thinning and viscoelasticity at a wide range of strain rates, oscillation frequencies, and amplitudes. The rheological tests show moduli dependence on both GelMA concentration and curing time. Together, this acoustic and rheological characterization can be used to inform the selection of GelMA scaffolds in tissue engineering applications, and this method can be used as a guide for characterizing other polymeric hydrogels.
Fast method for the determination of radiation-relevant eigenmodes of underwater structures when using FEM shell elements (“modal reduction”)
Authors: Burgschweiger Ralf , Schäfer Ingo , Sachau Delf , Ehrlich Jan
Published: November 2023

A self-developed code based on the BEM for the determination of the backscattered sound pressure level in the far field was extended so that additional FEM shell elements and thus elastic material properties can be considered. For this purpose, a separate FEM equation system is built up and directly integrated into the system of the BEM via corresponding transformation matrices. A common variant for solving the FEM-specific parts is to use a solver based on eigenvalue calculations, which provides the corresponding eigenfrequencies and eigenvectors of the uncoupled FEM equation system for a given upper cutoff frequency. It can be observed that only a part of the determined modes has a considerable sound radiation efficiency and is therefore relevant for the result. An algorithm determines these modes by a fast post-processing routine considering a given percentage, reduces the size of the eigenvalue equation system accordingly, and thus shortens the solution time. Furthermore, it was investigated whether the condition of the entire system of equations is improved by removing the irrelevant modes when using iterative solution methods and whether the number of iterations can thus be reduced. The paper describes the basics of FEM coupling with BEM, presents the reduction algorithm used and shows the results obtained for corresponding test structures depending on the reduction percentage used.
Estimation of the low-wavenumber component of turbulent boundary layer pressure field using vibration data
Authors: Abtahi Hesam , Karimi Mahmoud , Maxit Laurent
Published: November 2023

In structures subjected to a high-speed flow, the convective region of the wall pressure field (WPF) beneath a turbulent boundary layer (TBL) plays a crucial role in their vibration behaviour. However, when it comes to underwater structures experiencing low-speed flow, they effectively filter out the convective domain of WPF and the bending wavenumber of structures align with the low-wavenumber domain of the WPF. As a result, the primary cause of vibration in this case is the low-wavenumber components of the WPF. Thus, accurate estimation of the WPF at low-wavenumber domain is crucial for predicting vibration responses of these structures. Existing models for WPF accurately predict the convective region but differ significantly in predicting the low-wavenumber levels. This numerical study aims to investigate the feasibility of estimating the low-wavenumber WPF by analysing measured vibration data from a flat plate excited by a TBL. The WPF's cross spectrum in the wavenumber domain can be linked to the cross spectrum of the plate's acceleration. By employing regularization techniques and solving an inverse problem, the low-wavenumber components of the WPF can be then estimated. Virtual experiments are performed to evaluate the accuracy of the studied process by comparing its prediction to the input WPF model.
Nonreciprocal vibrations of discretized finite elastic structures with spatiotemporally modulated material properties
Authors: Geib Nathan , Goldsberry Benjamin M. , Wallen Samuel P. , Naify Christina , Haberman Michael R.
Published: November 2023

Elastic waveguides with time- and space-dependent material properties have received great attention as a means to realize nonreciprocal propagation of small-amplitude mechanical waves in unbounded elastic media. Previous works have shown that propagating waves in a modulated medium violate reciprocity by means of asymmetric frequency and wave number conversion between two counterpropagating modes. We previously investigated nonreciprocal longitudinal and transverse vibrations in a finite elastic waveguide with time- and space-dependent material properties using a semi-analytical coupled-mode theory The model employs the mode shapes of the non-modulated beam as the orthogonal basis functions to describe the nonreciprocal vibrations of beams with spatiotemporally modulated properties. The present study extends previous work to consider vibrations of Euler beams with spatially discretized stiffness that are modulated in time and phased relative to each other to mimic spatiotemporal modulation. This is achieved by approximating the discretized stiffness and then employing the mode shapes of the beam with unmodulated discretized stiffness to predict the nonreciprocal vibrational response of the beam when subjected to spatiotemporal modulation. We perform a parametric study of the system parameters and discuss how this model can be used to define requirements of future systems that can be used for experimental demonstration.
Acoustic black hole designs for circular beams under axial loading
Authors: Sepehrirahnama Shahrokh , Oberst Sebastian , Lai Joseph C. S.
Published: November 2023

Acoustic Black Hole (ABH), as a non-reflecting wave effect, has been realised in beams and plates by locally changing their thickness. Geometrical ABH designs stem from their transverse-load bearing properties, assuming isotropic material properties associated with engineering materials (e.g., steels). The underlying physics is to manipulate stiffness locally for a transversely-loaded structure, leading to a change in the elastic wave speed. However, the same ABH would have limitations for axial loading, i.e., slender beams for which longitudinal waves dominate. Here, we present a wave propagation approach using wavefront tracking to identify a potential ABH for axially-loaded circular beams. We study wave propagation in three exponential designs of finite length, monitoring the wave-travel time. Indicative of an effective ABH in finite length sections, the wave-travel time increases compared to the case of a beam without ABH. By employing the wave front tracking method for the design of an ABH with axial loading, it is possible to verify the effectiveness of ABHs. Also, various material models, e.g., orthotropic materials such as wood, and different loading conditions can be considered, which opens a new avenue in applications of ABH phenomena beyond conventional vibro-acoustic control problems.
A focus on ocean acoustics education
Authors: Scowcroft Gail , Vigness Raposa Kathleen , Knowlton Christopher , Morin Holly , Hotaling Liesl
Published: November 2023

The clear need for ocean acoustics education led to two initiatives in 2023. In January, the U.S. National Academy of Sciences (NAS) formed a committee to research the state of ocean acoustics education in the country and determine needs and opportunities for the discipline. In May, the theme of the fifth Global Ocean Science Education (GOSE) Workshop was ocean acoustics. The workshop brought together 70 participants from a dozen countries. These delegates, representing the research, business, policy, and education sectors, shared their knowledge on a suite of key topics in underwater acoustics and education. Delegates discussed the importance of integrating ocean acoustics into ocean education and ocean literacy initiatives, workforce development through an ocean acoustics microcredentials program, and addressing the needs of the global ocean acoustics community. The needs identified during the NAS study and the GOSE Workshop include the imperative to raise awareness of careers in ocean acoustics in pre-collegeeducation, as well as undergraduate education, more opportunities for training at the technician level, and easy to access educational resources, such as those found on the Discovery of Sound in the Sea website (www.dosits.org). Recommendations from the NAS study and the GOSE Workshop will be shared during this presentation.
My favorite resources for teaching musical acoustics
Authors: Dostal Jack
Published: November 2023

I teach a Physics of Music class at Wake Forest University. Students from a broad range of majors and backgrounds take the class to fulfill a science divisional requirement for graduation. In this talk I will describe how I incorporate some of my favorite online resources into my instruction. Some of these include the Sound and Waves section of the Physclips web platform created by Joe Wolfe at the University of New South Wales. I also frequently draw from Dan Russell’s Acoustics and Vibration Animations at Penn State University. In addition, I find that tools and resources such as online spectrograms and live-streamed music fit well within my course.
Flying disc noise as an introduction to acoustic signal processing
Authors: Dalton Kyle S.
Published: November 2023

Flying disc sports such as ultimate frisbee and disc golf continue to grow in popularity around the world. Despite the ubiquity of the flying disc in leisure and sport, descriptions of disc flight are largely heuristic and anecdotal, with minimal quantitative investigation into in-flight behavior. This work has two primary goals. First, by throwing a variety of discs over an array of microphones, we will assess how in-flight properties of the disc impact the recorded acoustic signals. Remote acoustic sensing offers several advantages over previous flying disc experiments: No instrumentation is placed on the disc and the disc can be observed over a longer flight than is possible with most visual measurement techniques. Second, we intend to create a low-cost, easy-to-implement experiment that introduces students to acoustic signal processing topics related to rotating machinery and array theory. Frisbees are cheap, readily available, and familiar to many students, making the flying disc a fun and accessible sound source that students can engage with from data collection to data analysis. This presentation will discuss the experimental setup, provide initial results, and offer lessons learned for educators and disc sport enthusiasts attempting similar projects.
Highly constrained low level fluid sensing in process pipes utilizing non-invasive ultrasonic methods
Authors: Davis Eric S. , Pillarisetti Lalith , Pantea Cristian , Saini Abhishek , Vakhlamov Pavel
Published: November 2023

Determination of the presence of hazardous waste in sealed pipes is a major issue of concern in many industries. Typically, when hazardous process piping needs to be opened, it is very difficult to truly know whether the pipe is empty, and thus free of hazardous material. Therefore, standard procedure is to assume worst case scenario and dedicate significant resources to Hazmat teams and containment when opening the piping or preparing it for decommissioning. In this work, we explore three separate ultrasonic-based techniques for very low-level fluid sensing in process piping. It was found that ultrasonic techniques suffer from several issues, including guided wave contamination, local resonance, overlap from other echoes, and more. To overcome these issues, three separate techniques were explored, including pulse-echo with subtraction, total focusing method (TFM) imaging, and another technique that exploits the local resonance of the pipe when it is fluid-loaded. It was found that, with proper calibration and signal processing, pulse-echo is an easy-to-use technique down to relatively low fluid levels. However, the best performance came from modified total focusing method imaging, which could detect extremely low fluid levels while being robust from false negatives (detecting no waste when there was waste).
Robotic sensing for buried pipes with sound waves
Authors: Yu Yicheng , Horoshenkov Kirill , Worley Rob , Anderson Sean
Published: November 2023

The length of buried sewer and drainage network in Europe is several million kilometres. Autonomous robots are being developed to inspect this massive network of pipes pervasively. These inspection technologies traditionally rely on CCTV images. However, detection of the condition of buried pipes with autonomous robots is challenging computationally. Acoustic waves provide an efficient alternative to conventional CCTV methods to detect a range of artefacts that can lead to pipe failure and map these conditions. This paper presents an acoustic method for simultaneous condition detection, localization, and classification in air-filled pipes. A microphone array is used to estimate the reflection coefficient from a range of artefacts. This information is used together with a regularization method. A wavelet basis function is adapted to enhance the fidelity of collected acoustic data. It is shown that the wavelet components can also be used to train and to test a support vector machine (SVM) classifier for the condition identification. This work can also inform the route planning and low-level control algorithms for autonomous robots which are being developed for the inspection of buried pipes.
Vessel and landside noise contributions from port activities: What does 2 years of data tell us?
Authors: Pandey Priyadarshi
Published: November 2023

Port Authority of NSW has developed a Port Noise Policy for the management of vessel and landside port noise at the port precinct level at Glebe Island and White Bay, Sydney, NSW. The implementation of this policy is currently underway and involves undertaking long term, unattended noise monitoring at multiple locations around the Port using directional sound level meters. Concurrent data for other key variables such as vessel movements and meteorology is also obtained from existing data APIs. This paper provides details around the methodology adopted to extract vessel and landside noise contributions from the broader ambient noise environment for Port activities. Detailed analyses of vessel and landside noise contributions is undertaken in the context of parameters such as vessel parameters and meteorology. The paper provides insights into the role of these variables in the context of measured noise levels and the spatial and temporal variations in noise around the Port.
Long tunnel noise propagation
Authors: Woolf Lachlan T. , Gange Michael , Tabacchi Mattia , Morris Adrian
Published: November 2023

The number of long tunnels in Sydney has increased in recent years with the development of underground road and rail projects. Understanding the propagation of noise along the tunnels and into the environment during the construction phase is important when assessing noise for 24/7 tunnelling operations. In-tunnel noise assessment of mechanical equipment is also required as part of the project's technical criteria and approvals. The prediction of in-tunnel noise levels is required from stationary sources such as ventilation fans and jet fans. The acoustic design of these tunnels is challenging as a feature of the acoustics of long spaces is that classical room acoustic theory is not applicable, since the assumption of a diffuse field does not hold with the extreme dimensional condition. This paper details the difference between in-tunnel noise measurements from an omni-directional noise source compared with the modelled results from 3D noise modelling software packages.
Assessment of environmental sound perception among listeners with hearing loss and cochlear implants
Authors: Harris Michael S. , Anwer Saba , Luzum Nathan , Shafiro Valeriy , Heller Laurie M.
Published: November 2023

Perception of environmental sounds (PES), encompassing informationally and/or aesthetically salient nonspeech, nonmusical sounds, is crucial for safety, independence, and quality-of-life among listeners with hearing loss. The aims of this study were (1) to systematically review methodologies used to assess PES among cochlear implant (CI) users and identify performance trends in this population, and (2) to present preliminary data using a novel PES task requiring inference of materials and actions generating environmental sounds. For aim 1, PES in quiet using open- or closed-set response formats were most commonly used. PES accuracy in pediatric (3 studies) and adult (16 studies) CI users was highly variable but generally mediocre (mean correct: 31–87%). Most studies were cross-sectional; only two evaluated PES prospectively before and after CI. No significant differences in accuracy were reported between CI candidates and CI users. PES correlated in with measures of speech perception and spectro-temporal processing. For aim 2, we present preliminary findings on identification of materials and actions responsible for generating environmental sounds among normal hearing listeners and listeners with hearing loss using hearing aids or CIs. We discuss the types of materials and actions that are most difficult for listeners with hearing loss and common sources of confusion.
Assessing listening effort in children: A child-appropriate dual-task paradigm investigating the influence of different noise conditions
Authors: Seitz Julia , Loh Karin L. , Fels Janina
Published: November 2023

In classrooms, children are often challenged by competing speech, loud background noises, or unfavorable room acoustics when listening to their educators. These challenging listening situations require more cognitive, attentional, and perceptual processing resources to understand speech, i.e., higher listening effort. This study introduces a dual-task paradigm to evaluate listening effort, specifically in children. The paradigm encompasses a word recognition task as the primary task and a serial recall task as the secondary task. The influence of multi-talker babble noise on listening effort is studied in an anechoic and reverberant environment with different signal-to-noise ratios. It further incorporates aurally-accurate sound reproduction allowing plausible listening situations appropriate to children’s smaller anthropometric sizes. The aim is to validate the newly developed paradigm in an experiment with children. The listening effort in noisy conditions is compared to a noise-free condition. Moreover, the influence of anechoic versus reverberant noise scenarios on listening effort is investigated.
Assessment of cochlear implant hearing outcomes using ecological momentary assessment in both controlled and real-world settings
Authors: Monaghan Jessica J. , Meng David , Poulos Marisa , Smith Zachary , Mejia Jorge
Published: November 2023

Laboratory tests of speech understanding demonstrate high effectiveness of cochlear implants (CIs) for individuals with severe-to-profound hearing loss. However, understanding real-world benefits remains challenging. Retrospective questionnaires may be unreliable due to recall bias and limited acoustic information. To address this, we used an Ecological Momentary Assessment (EMA) smartphone app to collect subjective feedback and acoustic data from CI recipients in lab and real-world settings. We characterised challenging acoustic environments for CI users and the influence of internal factors on self-ratings of environmental noisiness, device benefit, and speech understanding. Twenty adults underwent cognitive tests, questionnaires, EMA, and the NAL Dynamic Conversation Test in the lab. Acoustic scenes were reproduced in an anechoic chamber to assess comprehension, familiarise participants with EMA, and establish benchmarks for real-world EMA data. Over four weeks, participants recorded experiences using the EMA app. Analysis of real-world EMA data revealed perceived noisiness was influenced by spectro-temporal properties and sound level. Self-reported communication factors were associated with environmental sound level and predictive of self-reported CI device benefit. Communication factors were also correlated with CI experience and cognitive performance. EMA offers valuable insights into CI recipients' real-world experiences, aiding customization and efficacy evaluation.
Sliding friction acoustics
Authors: Jerome Trevor W. , Kurdle Maggie , Bonomo Anthony
Published: November 2023

Contact interactions generate acoustic energy in complicated ways, dictated by dozens of system parameters. The ability to accurately predict these stochastic friction forces and resultant acoustic energy from first principles is currently lacking. A summary of experimental tests with sliding and stick-slip of metal-on-metal contact are presented to provide insight into the influence of roughness, sliding velocity, and normal load on the generated acoustics. Normal load and normal displacement increase in dynamic amplitude under stick-slip conditions relative to smooth sliding. In the current configuration, stick-slip also produces an excess of up to 30 dB SPL, relative to smooth sliding. Relationships between normal load, surface roughness, tangential velocity, and acoustic output are explored, and parameters are tuned to fit these variables using an existing empirical relationship from the literature.
Analyzing symmetry-based techniques to reduce the computation time of sound power estimates obtained from vibration measurements
Authors: Bacon Ian C. , Shepherd Micah , Sommerfeldt Scott D. , Blotter Jonathan D.
Published: November 2023

Two significant drawbacks have been identified in an emerging vibration-based sound power (VBSP) method when compared to its pressure andintensity-based competitors. Firstly, the measurement time increases significantly when dealing with large structures or higher frequencies. Secondly, sound power is computed through the matrix triple product veH(ω)R(ω)ve(ω) which has expensive temporal costs as the structure becomes more complex and for dense scans. This work focuses on the latter concern pertaining to the computation time of the R matrix. Previous research has shown that leveraging the inherent symmetries arising from reciprocity between element radiators across the surface of a structure expedites the construction of the R matrix. Additionally, theoretical work has revealed further symmetries in unbaffled structures, offering potential improvements in computational efficiency. To demonstrate this reduced computation time, simple case studies implementing the R matrix symmetries were conducted using experimental data from various unbaffled geometries. Furthermore, approaches to reducing the temporal costs of this specific matrix triple product, which exhibits these symmetries, will be investigated to enable real-time results within minutes after conducting dense scans. Reducing the computation time will contribute to the VBSP method becoming an efficient and reliable technique for measuring sound power in various applications. [Funding for this work was partially provided by the National Science Foundation (NSF).]
Structural stability analysis for a Maglev design
Authors: Zhang Zeyi , Hu Ying , Zhang Zhe , Huang Lixi
Published: November 2023

Magnetic levitation train has the advantage of low vibration and noise compared with ordinary railway systems. It also has the potential to become more energy efficient if permanent magnets are properly incorporated. However, suspension forces provided by the magnetic fields may have dynamic instability that needs to be overcome before such design can be utilized. This talk presents a design of permanent magnet group that overcomes the instability of at least one degree of freedom compared with rudimentary levitation configuration. The magnetic forces between components are derived analytically and the system eigen-value problem is presented. It is shown that, in the rudimentary design, unstable modes occur in two degrees of freedom (lateral and rotational), and the new design suppresses one of the two instability modes (rotational). Initial experimental demonstration is also provided.
On the small flat vowel systems of Australian languages
Authors: Butcher Andrew
Published: November 2023

The vowel systems of Australian languages could best be characterized as “small and flat.” Small, because about 50% of Australian languages have a three-vowel system with another 20% or so distinguishing four or five vowel qualities. Flat, because, while there is the usual degree of separation between front and back vowels along the horizontal (F2) axis of the vowel space (700–2400 Hz), variation along the vertical (F1) axis is typically restricted to a range of 350-900 Hz, leaving the ‘close’ vowel area noticeably under-exploited. Thus, rather than the [i, a, u] values as traditionally transcribed, 3-vowel languages have the phonetic (Cardinal Vowel) qualities of [e, ɐ, o] and 5-vowel languages have [e, ɛ, ɐ, ɔ, o]. I suggest that, as with the atypical consonant inventories, the lack of close vowels in these languages may be explained in terms of the historical influence of the hearing status of their speakers. Reduction in vowel space in individual speakers is one consequence of hearing impairment caused by otitis media, which can reduce hearing levels under 500 Hz by up to 40 dB. The Australian Aboriginal population has the highest prevalence of otitis media in the world by far (50 to 90%).
Tank test results of synthetic aperture sonar image reconsturction using two frequency bands
Authors: Kim Sea-Moon , Lee Pan-Mook , Lee Ji-Eun , Baik Kyungmin , Lee Chong-Moo , Choo Yeon-Seong , Jang Jeong-Bin
Published: November 2023

Synthetic aperture experiments have been done in water tanks using two different frequency bands. Their center frequencies are around 25 kHz and 300 kHz, respectively. The lower frequency system has eight equally spaced receiver channels with one wavelength distance and the higher frequency one has sixteen receiver channels with about seven wavelength spacing. Five different types of structures were selected as sonar targets. They are sphere, cylinder, octahedron-shape structure, star-shape structure, and an in-plane grid target. The sphere and cylinder were floating in the water column while the others were located on the tank bottoms. As the transmitting signals linear frequency modulation was applied. Sonar images were reconstructed by synthetic aperture processing and the deviated motion from the perfect rectilinear trajectory due to the vibration of the vertical support was compensated by using motion sensor data and receiver signals. Synthetic aperture images were experimentally generated using the two different frequency bands and compared. [This research was supported by KIMST funded by the Agency of Korea Coast Guard (KIMST-20210547).]
Three-dimensional raytrace modeling of the New England seamounts acoustics experiment
Authors: Jerome Thomas S. , Ballard Megan S. , Sagers Jason D. , McNeese Andrew R. , Miller James H. , Bonnel Julien
Published: November 2023

The 2023 New England Sea Mounts Acoustics (NESMA) experiment took place from April to June at the Atlantis II Seamount Complex. One goal NESMA seeks to address is to further the understanding of acoustic propagation around prominent bathymetric features and associated diffraction and refraction effects. The bathymetry of the experimental site exhibits extreme variability with a difference in elevation of three kilometers from the abyssal plane to the peaks of the seamounts and slopes upwards of 15°, which has a significant influence on bottom-interacting acoustic propagation. As part of the experiment, multiple broadband impulsive sound sources were deployed around the seamounts, including explosive charges, seismic air-gun, and rupture induced cavitation events. Three-dimensional ray trace models of the experiment are presented for comparison with the measured acoustic receptions. Model results are primarily concerned with signals received on three single-channel acoustic recorders deployed on the abyssal plane near the seamounts. Comparisons provide insight into variation in the structure of the measured arrivals associated with varying ray paths refracted around and between the seamounts for different source positions. The influence of geotechnical properties on the measured signals is also assessed through modeling. [Work supported by ONR.]
Diurnal measurements of sound attenuation (100 Hz—10 kHz) in a shallow (1-2 m), seagrass (Zostera marina) meadow are impacted by photosynthetic activity and water column height
Authors: Barosin Emily B. , Warren Joseph D.
Published: November 2023

Seagrass meadows are important habitats that provide a variety of ecosystem services. As the seagrasses photosynthesize, they fill their vascular tissues with oxygen which is also released as bubbles into the water column. Measurements of sound attenuation were made in August 2022 in a shallow (1–2 m water depth) Zostera marina meadow in Shinnecock Bay, New York. Sound sources included tones (100 Hz–2 kHz) transmitted over an 8hour period (0800–1600 local time) and a 10 kHz Fishtek pinger operating over a 3 day period. Hydrophones were placed in the seagrass meadow at ranges of 1, 3, and 7 m from the source to determine attenuation. Vertical profiles of temperature, salinity, and dissolved oxygen were measured at the study site during the 8 hour tonal source experiment, and solar irradiance and tide level for Shinnecock Bay were obtained for the 3 day study period. Peak to peak sound pressure levels varied by more than 31 dB over a diurnal period for the 10 kHz signals. Sound attenuation of lower frequency tones varied from 9 to 30 dB both with dissolved oxygen (a proxy for photosynthetic activity of the seagrass) as well as water column height.
Development on acoustic louvre to enhance the noise reduction performance of acoustic balconies
Authors: Lu King Kwong , Yeung Maurice , Wong Kit , Lin Fanni
Published: November 2023

A balcony in a domestic flat provides residents an outdoor living space as well as better ventilation to improve indoor air quality. However, balcony door when open for natural ventilation will allow outdoor noise transmit into the residential flat. Innovative acoustic balcony design by installation of sound absorptive panels onto the balcony ceiling and side walls of balcony has been implemented in Hong Kong for mitigating road traffic noise. Recently, combined balcony with an extension of utility platform for installation of air-conditioning outdoor unit has become popular. However, the parapet of the extension used a three-sided air grille with 70% permeability for heat dissipation purpose. Acoustically, the issue is noise leakage through the air grille comparing to a solid parapet. This paper discusses the development of acoustic louvres to replace the air grille in order to improve the noise reduction abilities of acoustic combined balconies. Several acoustic louvres of different configuration are developed. Validation of improvement in noise reduction of the acoustic combined balcony in a mock-up flat is conducted in accordance with ISO 16283-3.
From ocean ambient noise to soundscape ecology
Authors: Cato Douglas H.
Published: November 2023

Ambient noise in the ocean has been studied for more than 80 years but recently there has been a tendency to use the word “soundscape” for what appears to be the same phenomenon. Ambient noise is usually defined as the background noise from all sources, excluding sounds from individual identifiable sources and is an important limitation on sonar performance and the use of sound by marine animals. The term “soundscape” has been used for decades outside of underwater acoustics with varying definitions depending on the application. Probably the most relevant is “soundscape ecology,” which comes from terrestrial ecology and includes the acoustic interaction between animals and between animals and their environment. A soundscape, therefore, includes all sounds in an environment, not just the background or ambient noise. Sounds from individual identifiable sources may have particular interest to marine animals especially if they are from conspecifics, predators, or prey. This paper discusses the value of applying the broader concepts of soundscapes and soundscape ecology to the underwater environment, the advantages of recognizing the distinction between soundscapes and ambient noise and the importance of soundscape ecology in understanding animal acoustic behavior and the effects of anthropogenic noise.