bluuebunny/crossref_metadata_2025 huggingface dataset:
Excess attenuation at the beach: A model validation
Authors: Vecchiotti Andrea , Ryan Teresa J. , Cobb Faith A. , Wilson Nia , Vignola Joseph , Turo Diego
Published: December 2020

This work presents a comparison between experimental results and numerical modeling of atmospheric sound transmission loss across a range that includes water and a sandy shore. This work is part of a larger project developing a numerical model of long-range (∼3 km) atmospheric acoustic propagation in littoral or riverine environments with a near-shore acoustic source and on-shore receivers. The narrow angle parabolic equation method used in this work accounts for wind and temperature variation with elevation along the acoustic propagation path. The beach is modelled as an equivalent fluid employing the Johnson-Champoux-Allard-Pride-Lafarge (JCAPL) model. This eight-parameters model is reduced to a one-parameter model by considering the sand as randomly packed spherical particles. The single parameter is the grain size. Measured grain size distributions of the sand and its change in water content with the distance from the water inform model development of the beach. Sound pressure levels predicted by three model variations are compared with measurements. Advantages and drawbacks of model complexity are presented. We show that short spans of saturated sand are effectively modelled with a fully reflective surface whereas longer spans of sand require varying levels of sound absorption.
Modeling the pure bending of plates with analog circuit models
Authors: Childs Carter J. , Thompson Stephen C.
Published: December 2020

Previous work created a way to model flexural bending of Euler-Bernoulli beams as an analog circuit model [C. J. Childs and S. C. Thompson, J. Acoust. Soc. Am. 145, 1895 (2019)]. Further work has been completed to expand the modeling technique from one-dimension into two-dimensions. This allows for enhanced accuracy in modeling physical structures, including a Timoshenko bar or pure bending of plates. The modeling technique will be presented to show bending of plates with comparable accuracy and computational resource advantages, as seen with the Euler-Bernoulli model.
Piezoelectric leaf-cell sensor for simultaneous density and compressibility measurement
Authors: Swett Dwight , Adams Robert , Deffenbaugh Max
Published: December 2020

In resonant piezoelectric sensors that measure fluid density and viscosity simultaneously the underlying physical mechanism is a thin shear boundary effect. A distributed traction develops over the resonator surface dependent on the product of density and viscosity. Accordingly, these sensors have insignificant dilatational interaction with the fluid and remain insensitive to fluid compressibility. Here we describe a novel sensor geometry sensing fluid compressibility as well as density and viscosity. The sensor utilizes a symmetric piezoelectric spoke structure to excite a circumferential “cell” geometry derived from a Rhodonea, or more commonly four-leaf roses, conformal mapping having a high degree of dilatational coupling to the fluid within and around the cell due to the curvilinear geometry resonance response. The coupling between the cell structure and the fluid volume creates a standing acoustic wave in the fluid and changes the resonance response of the piezoelectric cell as the density and compressibility of the fluid change. The admittance spectrum of the piezoelectric sensor is well fit by the Butterworth-Van Dyke model for a piezoelectric transducer, and the effective mass, damping and compliance of the model are modulated by the properties of the fluid. Measurements are presented on fluids of known density, viscosity, and compressibility.
Increasing piezoelectric effect in radially polarized soft lead zirconate titanate (PZT) by pressure treating and its practical applications
Authors: Aikins Eric K.
Published: December 2020

Soft PZT/NAVY type II ceramic material is commonly used for underwater acoustics sensing applications due to its softer composition and higher electromechanical coupling coefficient than Navy Type I or Type III materials but can also be used for projector applications. The effective coupling coefficient (k-eff) of soft PZT hollow cylinders can be improved from 0.33 to 0.40 (20%) under axial pressure treatment and remains stable with time. The sensitivity of dielectric constant and piezoelectric modulus to compressive stress for hard and soft tangentially polarization ceramics is shown to be less than radially polarized ceramics. Effect of planar stress in spheres at moderate and deeper depths are presented. An experimental method is introduced that utilizes an air-pressurized chamber to deliver stress loads to the piezoceramic. The electromechanical properties (including k-eff, dielectric constant, piezoelectric modulus, and compliance) are measured dynamically using an impedance analyzer and resonance/antiresonance techniques. Pressure treated cylinders with improved k-eff is shown to be suitable for application that utilize pressure equalized (free-flooded) transducer designs and for air-backed transducer designs under moderate depths. The improved k-eff improves the power factor bandwidth of the transducer is further studied using equivalent electrical circuit model including the effect of external pressure.
Penn State's graduate program in acoustics
Authors: Sparrow Victor W. , Russell Daniel A.
Published: December 2020

This poster describes faculty research areas, laboratory facilities, student demographics, successful graduates, and recent enrollment and employment trends for the Graduate Program in Acoustics at Penn State—the only program in the U.S. offering the Ph.D. in Acoustics as well as M.S. and M.Eng. degrees. The Graduate Program in Acoustics is an interdisciplinary program with faculty from a variety of academic disciplines; administratively aligned with the College of Engineering and closely affiliated with the Applied Research Laboratory. Research areas include: structural acoustics, nonlinear acoustics, architectural acoustics, signal processing, aeroacoustics, biomedical ultrasound, transducers, computational acoustics, noise and vibration control, acoustic metamaterials, psychoacoustics, and underwater acoustics. Course offerings include fundamentals of acoustics and vibration, electroacoustic transducers, signal processing, acoustics in fluid media, sound and structure interaction, digital signal processing, experimental techniques, acoustic measurements and data analysis, ocean acoustics, architectural acoustics, noise control engineering, nonlinear acoustics, outdoor sound propagation, computational acoustics, biomedical ultrasound, flow induced noise, spatial sound and three-dimensional audio, and the acoustics of musical instruments. More than 750 Penn State Acoustics graduates serve widely throughout military and government labs, academic institutions, consulting firms, and industry.
An online Master's Degree in acoustics from Penn State
Authors: Russell Daniel A. , Sparrow Victor W.
Published: December 2020

In addition to the doctoral and master's degrees offered to resident students, the Graduate Program in Acoustics at Penn State offers online access to graduate level courses leading to the M.Eng. degree in Acoustics. Lectures are broadcast live to students scattered around the world, while archived recordings allow working students to access lectures at their convenience. Students earn the M.Eng. in Acoustics degree by completing 30 credits of coursework and writing a capstone paper. Since 1987, more than 175 distance education students have completed the M.Eng. in Acoustics degree. Many other students take individual courses as non-degree students. Courses offered online include: elements of acoustics and vibration, elements of waves in fluids, electroacoustic transducers, signal processing, acoustics in fluid media, structural acoustics, digital signal processing, aerodynamic noise, acoustic measurements and data analysis, ocean acoustics, architectural acoustics, noise control engineering, nonlinear acoustics, outdoor sound propagation, computational acoustics, biomedical ultrasound, flow induced noise, spatial sound and 3-D audio, and the acoustics of musical instruments. This poster describes the distance education experience leading to the M.Eng. degree in Acoustics from Penn State and showcases student demographics, capstone paper topics, enrollment statistics and trends, and the success of our graduates.
East Carolina University Engineering: A new option in graduate acoustics education
Authors: Ryan Teresa J. , Foeller Jeff , Muller-Borer Barbara , Sylcott Brian , Vignola Joseph , Turo Diego
Published: December 2020

East Carolina University (ECU), located in Greenville, NC, is a large public university located in the heart of North Carolina's coastal plain. ECU's Department of Engineering was founded in 2004 and has grown to have a faculty of 31 and a relatively stable undergraduate enrollment of approximately 500. Undergraduate students earn a B.S. in Engineering with the choice of six areas of concentration: Biomedical, Bioprocess, Electrical, Environmental, Industrial and Systems, or Mechanical Engineering. Since 2013, the department has offered undergraduate research opportunities and elective courses in vibrations and acoustics. In Fall 2019, the department enrolled the inaugural class of students for a new research-focused Master of Science in Mechanical Engineering (MSME). The MSME program offers coursework and research opportunities in acoustics and vibrations. Qualified applicants are eligible to apply for paid research fellowships and assistantships. Specific recent topics of research have included (1) dynamics of and applications for arrays of resonant attachments (such as mass detection and vibration control) and (2) the study of atmospheric acoustics in the near-shore environment. Research collaborations with The Catholic University of America, ECU's Center for Sustainability, and ECU's Water Resources Center strengthen the breadth of the experience available to ECU's MSME students.
Highlights of the first acoustical description of the intonation of the Spanish in Bucaramanga, Colombia
Authors: Roberto Yeimy J.
Published: December 2020

This study presents the first acoustical description of the intonation of the Spanish in Bucaramanga, a northeast city in Colombia. A total of 376 utterances from 4 speakers was analyzed, including statements and interrogatives, elicited in spontaneous, semi-spontaneous and read contexts. Intonational analysis confirms that Bucaramangan Spanish is closest to Cali's variety of Colombian Spanish; however, a wide variety was found in the realization of nuclear accents, boundary tones, and prosodic phrasing. Statements are usually realized with a low nuclear accent when neutral, but a high nuclear accent appears when they are not neutral, in some cases showing upstep features (emphatic statements) and downstep features (in the tonal boundaries of requests). Yes-No questions, as well as WH echo questions, are realized with a rising boundary tone. In all the other instances the boundary tone is falling. This study contributes to the description of the intonation of Latin-American Spanish varieties and supports Hualde and Prieto's (2016) proposal that intonation should be discussed at two levels: the phonological level, and a broad phonetic level.
Graduate study at the Catholic University of America: Towards a century of acoustics
Authors: Vignola Joseph , Turo Diego , Guan Shane , Ryan Teresa J.
Published: December 2020

The Catholic University of America (CUA) has a graduate program with a long history in acoustics dating back to the early 1930s. The acoustics program moved to the School of Engineering in the 1960s when there were strong needs in underwater acoustic studies to meet U.S. Naval applications. Recent interests include acoustical engineering, acoustic metamaterials, and environmental acoustic. Currently, a variety of graduate level acoustic courses are being offered in the CUA's Mechanical Engineering Department. Students can pursue a MS in Mechanical Engineering or Ph.D. with research in acoustics or vibrations. The courses in the program include a two-course sequence in fundamentals of acoustics, and more focused courses in ocean acoustics, atmospheric acoustics, acoustic metrology, marine bioacoustics, nonlinear vibration, acoustic imaging, and acoustic metamaterials. In addition, this program enables working professionals in the Washington, DC, area to complete a graduate degree while continuing fulltime employment by offering face-to-face classes on-site at a number of off-campus sites. These sites including the Naval Surface Warfare Center, Carderock, the Army's Night Vision lab, as well as Newport News Shipbuilding. The group has active research collaborations with the US Naval Research Laboratory, NSWC Carderock, East Carolina University and, Università Politecnica delle Marche, Italy.
Studying acoustics within the College of Engineering at the University of Nebraska – Lincoln
Authors: Wang Lily M. , Ryherd Erica E. , Turner Joseph A. , Zhu Jinying
Published: December 2020

This poster highlights three groups in the College of Engineering at the University of Nebraska – Lincoln (UNL) in which graduate students can study and conduct research in acoustics. Dr. Lily Wang and Dr. Erica Ryherd are active in architectural acoustics and noise control (http://nebraskaacousticsgroup.org ) within the Durham School of Architectural Engineering and Construction, based at UNL's Scott Campus in Omaha. Dr. Jinying Zhu in Civil and Environmental Engineering (also based on UNL's Scott Campus in Omaha) focuses in structural acoustics, using ultrasonic waves for concrete evaluation. Dr. Joseph Turner in Mechanical and Materials Engineering (based at UNL's City Campus in Lincoln) studies ultrasound propagation through complex media for quantitative characterization of materials/microstructure (http://quisp.unl.edu ). There is an active student chapter of the Acoustical Society of America on Scott Campus that regularly schedules meetings and activities. In the past year, these have included a car stereo competition, guest lectures, and visits to local acoustic performances. The graduate-level acoustics courses and lab facilities at UNL within the College of Engineering are presented, and the research interests and achievements of our faculty, graduates, and students are highlighted.
Graduate studies in acoustics at Northwestern University
Authors: Cole Jennifer , Bradlow Ann , Goldrick Matthew
Published: December 2020

Northwestern University has a vibrant and highly interdisciplinary community of acousticians. Of the 13 ASA technical areas, 3 have strong representation at Northwestern: Speech Communication, Psychological and Physiological Acoustics, and Musical Acoustics. Sound-related work is conducted across a wide range of departments including Linguistics (in the Weinberg College of Arts and Sciences), Communication Sciences & Disorders, and Radio/Television/Film (both in the School of Communication), Electrical Engineering & Computer Science (in the McCormick School of Engineering), Music Theory & Cognition (in the Bienen School of Music), and Otolaryngology (in the Feinberg School of Medicine). In addition, The Knowles Hearing Center involves researchers and labs across the university dedicated to the prevention, diagnosis and treatment of hearing disorders. Specific acoustics research topics across the university range from speech perception and production across the lifespan and across languages, dialect and socio-indexical properties of speech, sound design, machine perception of music and audio, musical communication, the impact of long-term musical experience on auditory encoding and representation, auditory perceptual learning, and the cellular, molecular, and genetic bases of hearing function. We invite you to visit our poster to learn more about the “sonic boom” at Northwestern University!
Underwater acoustics and ocean engineering at the University of Rhode Island
Authors: Van Uffelen Lora , Miller James H. , Potty Gopu
Published: December 2020

Underwater acoustics is one of the primary areas of emphasis in the Ocean Engineering Department at the University of Rhode Island, the first Ocean Engineering program in the United States. The program offers Bachelors, Masters (thesis and non-thesis options) and Ph.D. degrees in Ocean Engineering. These programs are based at the Narragansett Bay campus, providing access to a living laboratory for student learning. Some key facilities of the program are an acoustics tank, a 100-foot-long wave tank, and currently the R/V Endeavor, a UNOLS oceanographic research vessel operated by the University of Rhode Island. A new Regional Class vessel is anticipated in 2022. At the graduate level, students are actively involved in research focused in areas such as acoustical oceanography, propagation modeling, geoacoustic inversion, marine mammal acoustics, ocean acoustic instrumentation, and transducers. An overview of classroom learning and ongoing research will be provided, along with information regarding the requirements of entry into the program.
Graduate studies in acoustics and noise control in the School of Mechanical Engineering at Purdue University
Authors: Davies Patricia , Bolton J. S. , Liu Yangfan , Li Kai Ming
Published: December 2020

The acoustics community at Purdue University will be described with special emphasis on the graduate program in Mechanical Engineering. Around 30 Purdue faculty study aspects of acoustics and closely related disciplines and so there are many classes to choose from as graduate students structure their plans of study to complement their research activities and to broaden their understanding of acoustics. In Mechanical Engineering, the primary emphasis is on understanding noise generation, noise propagation, and the impact of noise on people, as well as development of noise control strategies including active noise control, experimental techniques, and noise and noise impact prediction tools. The noise control research is conducted at the Ray W. Herrick Laboratories, which houses several large acoustics chambers that are designed to facilitate testing of a wide array mechanical systems, reflecting the Laboratories' long history of industry-relevant research. Complementing the noise control research, Purdue has vibrations, dynamics and electromechanical systems research programs and is home to a collaborative group of engineering and psychology professors who study human perception and its integration into engineering design. There are also very strong ties between ME acoustics faculty and faculty in Biomedical Engineering and Speech Language and Hearing Sciences.
Dashboard system to track cumulative exposure to sound levels during live music instruction
Authors: Goel Akansha , Joshi Eeshan , Kwee-Bintoro Ted , Gopal Kamakshi , Chesky Kris , Champlin Sara , Albert Mark V.
Published: December 2020

During music rehearsals, students and teachers are regularly exposed to unsafe sound levels; hearing loss is a major concern among musicians. By providing real time feedback to music instructors, we can persuade them to modify their teaching methods to achieve safe listening conditions. To accomplish this, we created a user-friendly dashboard that displays the cumulative sound energy being collected in real-time. Since there are few standards for limiting music exposure, we used NIOSH standards for industrial noise exposure as the permissible exposure limit (PEL). Circular dials on the dashboard were programmed to display the amount of exposure relative to the PEL. To aid in identifying the type of exposure, each dial represents the amount of sound accumulation in a band of frequencies relative to typical human speech: below (15Hz–85 Hz), at (85Hz–252 Hz), and above (242Hz–24 675 Hz). The dashboard also displays an equalizer representing the instantaneous microphone input. After each session, the cumulative exposure data can be sent out in email format. Inexpensive and convenient to use, this dashboard will enable music instructors to make informed decisions on how to best modify their teaching approaches to reduce the risk of hearing loss.
Applications for new high-frequency impact ratings
Authors: Lo Verde John , Rawlings Samantha , Dong Wayland
Published: December 2020

In January 2020, a new ASTM classification standard that defines high-frequency impact ratings was published as ASTM E3222. These ratings are named High-frequency Impact Rating, or HIR, for field testing, and High-frequency Impact Insulation Class, or HIIC, for laboratory testing. These ratings describe the high-frequency region of a proposed two-rating method of evaluating impact noise isolation [LoVerde and Dong, J. Acoust. Soc. Am. 141 (2017)], in which low- and high-frequency components are evaluated independently. This paper addresses practical use of HIR and HIIC, focusing on applications where exclusive use of HIR or HIIC can be beneficial.
AASHTO specifications for noise evaluations of pavement surfaces
Authors: Lodico Dana
Published: December 2020

Three specifications for the noise evaluation of pavement surfaces have been developed for the American Association of State Highway Transportation Officials (AASHTO). These include (1) the On-Board Sound Intensity (OBSI) method (AASHTO T-360-16) of directly measuring noise generated at the tire-pavement interface in isolation of other noise sources, (2) the Statistical Isolated Pass-By (SIP) method (AASHTO TP 98-13) of measuring noise from isolated vehicles in existing traffic, and (3) the Continuous-Flow Traffic Time Integrate (CTIM) method (AASHTO TP 99-18) of capturing the sound from existing traffic for all vehicles on all roadway lanes. This presentation will describe and compare the procedures of the three AASHTO measurement methods used for the noise evaluation of pavements.
Psychoacoustic and noise annoyance of hard disk drive affects acoustic ergonomics and emotional wellness of consumers
Authors: Ma YiChao , Chin Cheng S.
Published: December 2020

Human hearing is a complex system due to the highly nonlinear nature of human ears. The ears perform many tasks simultaneously from identifying sound direction, estimating a distance from a sound source, masking of sound, and evaluating the noise. The objective sound power measurement is unable to convince the subjective nature of sound evaluation. Psychoacoustic measures such as sharpness, roughness, loudness, and fluctuation strength begin to show importance in understanding the quality of the sound from small interior such as Hard Disk Drive (HDD), which present in the most mobile consumer laptop. Two sets of jury tests have been performed to quantify the degree of HDD noise annoyance with psychoacoustic on broader age groups. The results indicate that the psychoacoustic have a close relationship with the HDD noise annoyance and age groups. The effect of laptop HDD on the user's emotional perceptions of different sound events caused by HDD's shows some participants are feeling less calm, annoyed, and excited as compared to before the jury tests.
Enhancing retention and recovery of particles in a standing wave chamber by modulating frequency and amplitude
Authors: Kumar Krishna N. , Campbell Tyler , Chitale Kedar , Lipkens Bart
Published: December 2020

Magnetic, electric, gravitational and acoustic field forces can be used to concentrate and separate particles. Here we focus on separating cells from a feed suspension using multidimensional acoustic standing waves to trap, cluster and gravitationally settle the cells. The application is concentration of cell cultures for cell therapy manufacturing. Process efficiency depends on frequency, power and settling time. Efficiency is enhanced by frequency and amplitude modulation. The acoustic standing wave is operated at its resonance frequency. Particle concentration and temperature affect the resonator frequency and may detune the system, resulting in lower retention. Exciting the field with multiple closely spaced frequencies increased particle retention between 5%–20% by changing the modulation and central frequency of the excitation signal. At the end of the retention process, the acoustic chamber is full of clusters which are sedimented into the collector. As cell clusters settle, they start dispersing in the fluid medium which impacts recovery. Use of an amplitude modulated acoustic wave during sedimentation reduces particle loss in the supernatant. As amplitude decreases, clusters start to settle. Before cells start to disperse, amplitude is increased to re-cluster the cells. This cycle repeats multiple times and increases cell recovery by 10%–30%.
Acoustic radiation force and torque on spheroids inside an ideal cylindrical cavity
Authors: Leão-Neto José P. , Silva Glauber T.
Published: December 2020

We perform a theoretical analysis of the radiation forces and torques produced on a spheroid particle by the acoustic modes of an ideal (with a rigid top and bottom and with soft or hard lateral walls) cylindrical chamber. Exact analytical expressions are obtained for a rigid particle and assuming the fluid inviscid approximation. A particular emphasis is given to the resonator's fundamental mode for which the axial and radial trap stiffnesses are calculated. The axial trap stiffness depends inversely with the cavity's height squared. We also predict that the radiation torque induces the particle to oscillate around its minor axis. The corresponding oscillation frequency is then determined. The theory is showcased for studying the dynamics of an Au microrod (modeled as an elongated spheroid) with a 20 μm-length and 2 μm-width in a water medium. In doing so, we use typical parameters of acoustofluidic devices (cavity's dimensions and energy density). The obtained results show terminal velocities of few micrometers per second, while the oscillation frequency is in the kilohertz range. In addition, a discussion on the dynamics of micro-/nanorobots of spheroidal shape propelled by ultrasound is outlined.
Spatiotemporal differential partitioning for one-dimensional fast acoustic streaming
Authors: Orosco Jeremy , Friend James
Published: December 2020

Historically, acoustofluidics modeling of streaming behaviors has relied heavily and almost exclusively upon formal asymptotic expansions in a relevant small parameter (e.g., the acoustic Mach number) in order to render tractable the highly nonlinear governing equations. However, the direction of modern acoustofluidics research dictates that no such order of magnitude separation between the acoustic and streaming fields can be generally relied upon—in extremal systems, formal asymptotic methods fail to properly extract the dynamics of interest. We outline progress toward the development of a theoretical approach that affords greater generality through its direct, explicit consideration and exploitation of all spatiotemporal scale disparities by partitioning differential operations. The method is applied to a one-dimensional problem of semiinfinite extent that, by convention, is classified as “fast streaming.” The compressible Navier-Stokes equations are solved in an approximate successive manner in order to obtain the acoustic and streaming fields. We show that the steady multi-temporal behavior of this result is characterized by a conservation of energy across acoustic and streaming scales.
Effects of word-frequency and social evaluation on phonetic accommodation
Authors: Foster Shawn C. , Cole Jennifer
Published: December 2020

Phonetic convergence between interlocutors is posited as a mechanism for long-term phonetic change (Pardo, 2006). This hypothesis requires that more frequent exposure to a phonetic variant increases the likelihood a speaker adopts said variant in their own speech. Certain instances of historical language change have, however, been theorized to represent divergence from, rather than convergence to, the speech patterns of an incoming group (Van Herk, 2008). We present the results of an artificial language learning experiment designed to investigate how social knowledge may mitigate frequency effects on phonetic convergence. Participants were exposed to nonce words produced by two speakers who differed systematically in their productions of front vowels. Participants in the experimental condition were informed that one speaker was a “native,” speaker of the language and an experienced teacher, while the other was a non-native speaker. The proportional frequency with which each speaker was heard varied across conditions. Subjects' own productions of the words were recorded after exposure. Results show an interaction between frequency and social bias. Test productions moved towards the socially upweighted, less frequent variant, but not to the same extent as one that was both upweighted and more frequent.
Bilingual talker identification with spontaneous speech in Cantonese and English: The role of language-specific knowledge
Authors: Lloy Angelina , Johnson Khia A. , Babel Molly
Published: December 2020

Previous research has shown that implicit or explicit knowledge about a language lends itself to improved talker recognition performance. In the context of this language familiarity effect, it is apparent that bilinguals are better at generalizing voice learning across their known languages compared to monolingual listeners [Orena et al., JASA, 146 (2019)]. Other work suggests that training in an unknown language generalizes to a known language more robustly than the reverse [Winters et al., JASA 123 (2008)]. The current study launches from these previous studies. This project uses excerpted Cantonese and English snippets from spontaneous interview speech from Cantonese-English bilinguals in a talker identification training experiment with Cantonese-English bilingual listeners and bilingual listeners with no knowledge of Cantonese (or related languages). Listeners are assigned to either Cantonese or English training, and then all listeners are tested on both Cantonese and English utterances to assess learning for the trained language and generalization to the bilingual's second language. Results of a multilingual questionnaire quantify listeners' code-switching abilities and multilingual competence, which, given prior research, should account for some individual differences. Using spontaneous productions, as opposed to read speech, improves the ecological validity of this research and broadens its implications.
The effect of accent salience on generalization of perceptual adaptation
Authors: Lee Dae-yong , Baese-Berk Melissa M.
Published: December 2020

Listeners often have difficulty understanding non-native accented speech. However, they are able to quickly adapt to non-native accented speech and generalize this adaptation to novel talkers. Previous studies that examined the mechanisms underlying generalization of adaptation mostly focused on acoustic similarity. That is, prior studies have demonstrated that acoustic similarity between non-native talkers in training and testing facilitates generalization. While acoustic similarity facilitates generalization, it is possible that salience of an accent (i.e., how noticeable the non-native accent is to a listener) also plays a significant role in generalization. That is, even if non-native accented talkers are acoustically similar to each other, generalization might not occur if a talker's non-native accent is not sufficiently distinct from the native-accented speech the listeners are familiar with. Thus, this study aims to examine the roles of salience of a non-native accent in generalization of perceptual adaptation to novel talkers. In the present study, native English speakers listen and transcribe English sentences read by Korean learners of English. Intelligibility (i.e., number of words transcribed) is measured to examine whether generalization to a novel non-native accented talker occurred. The results of the study will inform our understanding of generalization of adaptation to non-native accented talkers.
Low-fidelity visual cues facilitate speech processing in a cocktail party scenario
Authors: Ugolini Margaret H. , Thompson Eric R. , Ennis Zachariah N. , Simpson Brian D.
Published: December 2020

Speech comprehension is enhanced when a talker's face is visible, and amplitude modulations in speech support intelligibility. Listeners may benefit from visual speech by extracting amplitude modulation cues, which are represented by the mouth aperture of the talker. This multimodal enhancement of speech is often desirable, but the visual presentation of a talker's face is not always feasible. The present study investigated the degree to which a “low-fidelity” amplitude-modulation cue – an LED that changed in luminance with the amplitude of the speech envelope – contributes to speech perception for a target signal (a phrase from the Coordinate Response Measure, CRM) presented with two competing CRM speech phrases. Each trial consisted of 3 simultaneous speech streams of 5 sequential CRM phrases each. One stream included a target phrase (defined by a preset call sign) and originated from a location directly in front of the listener; competing sequences were placed at + /- 10 deg relative to that location. Listeners responded with the color and number associated with the target call sign. The presence of amplitude modulation cues and target timing cues enhanced performance. Further effects of cue type by signal-to-noise ratio will be discussed, as well as applications and future work.
Machining process monitoring with vibration signal based manifold learning
Authors: Wang Jing , Hui Mingxin , Liu Bin , Wang Xun , Cheng Xiaobin , Yang Jun
Published: December 2020

Machining process monitoring based on vibration sensing is a growing demand in smart manufacturing. However, in real factories, massive process conditions which include thousands of shapes of workpieces and thousands of combinations of cutting parameters, such as spindle speed, feed rate and cutting depth, are designed and used in manufacturing. Manifold learning is able to extract essential and distinct features from the vibration signal and helps to monitor and recognize different process conditions. In this paper, the dataset, including slight and huge variation of cutting parameters and workpiece shapes, are collected for analysis. Different manifold learning algorithms are utilized and compared to mine the essential features and reduce the interference of non-sensitive features. The generalization ability of different manifold learning algorithms are discussed to fit the various process conditions. Convolutional neural networks are employed to evaluate the monitoring accuracy. The experimental results show that the features obtained by the manifold learning distinguish vibration signals of different cutting parameters in low dimensional space and give a protentional way to construct effective monitoring systems. The generalization ability to different workpieces and cutting parameters and its limitation are discussed.
A modeling of synthetic aperture Image of a partially buried rigid cylinder on a flat boundary
Authors: Baik Kyungmin , Kim Wan-Gu , Ryue Jungsoo
Published: December 2020

Synthetic Aperture Sonar is a side-looking sonar that can obtain the equal resolution of the sonar images in lower frequencies than the conventional frequency ranges of Side Scan Sonar. The current study shows a part of the works being developed in the incorporation of the prototypes of Synthetic Aperture Sonar. As well as the conventional 2-D SAS, the system also has the bathymetric imaging in mind. In order to test the parameters and the algorithms imbedded in the system, a partially buried rigid cylinder was adopted as a simulation target for the broadside incident and the scattering amplitude by the cylinder was calculated by the Kirchhoff approximation. The features of monostatic scattering by a partially buried objects on the boundary are heavily dependent on its exposed surface out of the boundary [K. Baik and P. L. Marston, IEEE J. Ocean. Eng. 33, 368 (2008)] due to the contributions by the flat boundary to the scattered direction. Delay of the reverberation between the boundary and the cylinder was considered by the inverse Fourier transform of total scattering form function [L. G. Zhang etal., J. Acoust. Soc. Am. 91, 1862 (1992)] in the modeling. Current study shows the effects the parameters of the scattering by the partially buried cylinder on the resulting simulated SAS images. [This work is supported by the project of “Development of towed interferometric Synthetic Aperture Sonar” (15-CM-SS-01).]
Blind estimation of the direct-to-reverberant ratio using a beta distribution fit to binaural coherence
Authors: Calamia Paul , Balsam Nava , Robinson Philip
Published: December 2020

Knowledge of the direct-to-reverberant ratio (DRR) between an acoustic source and a listening position or receiver can be useful for various acoustic and audio applications including dereverberation, source distance estimation, automatic speech recognition, and binaural synthesis. While the DRR can be computed easily from a room impulse response (RIR), blind estimation using acoustic sources of opportunity is necessary when such RIRs are not available. In this presentation, we describe an approach for blind estimation of the DRR which uses the magnitude-squared coherence (MSC) between the two channels of a binaural signal. The method involves fitting a beta distribution to the MSC values, aggregated over time and frequency, and deriving the estimate from the relationship between the DRR and the shape parameters of that distribution. Validation experiments utilizing speech convolved with binaural RIRs collected from a variety of publicly available datasets yield DRR estimates that are within the just-noticeable difference for DRRs in the range -15 to + 18 dB.
Concert hall preference: Investigating key factors related to overall average and individual preference
Authors: Neal Matthew T. , Vigeant Michelle C.
Published: December 2020

A holistic approach to study individual preference in concert hall acoustics is difficult to achieve. A careful balance must be struck between using well-controlled laboratory testing conditions and maintaining natural, realistic auralizations. To achieve this balance, measurements were made in 21 concert halls across North America and Europe using spherical-array processing techniques for spatially accurate auralizations, which included realistic instrument directivity. Measurements were made at 20 standard orchestral instrument locations at a seat 15 m from the stage. Using this database, a subjective study has been conducted, comparing 14 representative halls rated for preference and ten significant subjective terms from concert hall acoustics literature. Principle components and factor analyses identified three to four representative and interpretable factors to describe concert hall perception. Correlation analyses were then conducted between these key factors and the average preference to determine overall consensus factors of preference. Since individual preference is inherently undefined, correlation between each individual’s preference ratings and these key factors and the repeatability of each subject were also investigated. Past literature suggests two distinct preference groups, but current results suggest the need for a continuous preference space, not represented by two groups and one variable alone. [Work supported by NSF Award 1302741.]
Histological effects on ex vivo rat tendon from focused ultrasound treatment
Authors: Smallcomb Molly , Elliott Jacob C. , Khandare Sujata , Butt Ali A. , Vidt Meghan E. , Simon Julianna
Published: December 2020

Focused ultrasound (fUS) therapy can induce controllable mechanical damage through bubble creation, oscillation, and collapse. However, highly collagenous tissues like tendon are resistant to mechanical fractionation with fUS. Our objective is to histologically evaluate whether fUS-induced mechanical disruption is achievable in rat tendon. Ex vivo Achilles (AT) and supraspinatus (ST) tendons were exposed to 1.5 MHz pulses of 0.1–10 ms repeated at 1–100 Hz for 15–60 s with peak pressures p+ = 69 MPa, p− = 24 MPa. B-mode ultrasound was used to monitor hyperechogencity during treatment. Samples were stained with Hematoxylin and Eosin (H&E) or alpha-nicotinamide dinucleotide diaphorase (αNADH-d). Results showed successful bubble creation for all samples; however, all samples did not show histological injury. Samples treated with 10-ms pulses at 1 Hz for 15 s displayed only slight disruption (2/5 AT, 2/5 ST). When treatment time increased to 30 s, thermal injury dominated over mechanical effects. Shorter pulse lengths (1 ms at 10 Hz; 0.1 ms at 100 Hz) resulted in localized fiber separation (5/10 AT, 2/10 ST). Future work will investigate how fUS influences mechanical properties of tendon and whether it can induce a healing response in vivo. [Work supported by NIH NIBIB EB027886; NSF GRFP DGE1255832 (Smallcomb).]
High fidelity hearing protection devices: Attenuation in human ears and manikin devices
Authors: Le Prell Colleen , Zaccardi Tess
Published: December 2020

Flatness of attenuation was measured for high-fidelity hearing protection devices (HPDs) using microphone-in-real-ear (MIRE) and behavioral real-ear-attenuation-at-threshold (REAT) protocols. In addition, participants completed the words-in-noise (WIN) test with and without HPDs, and provided subjective ratings of perceived sound quality via surveys administered after listening to music with and without HPDs. Attenuation was also measured using a manikin device, with both the manikin-based microphone and the MIRE probe tube used to make measurements inside the artificial ear coupler. Among human participants, statistically significant correlations revealed decreased WIN performance and poorer music quality ratings as achieved HPD attenuation increased. There was also a statistically significant correlation in which shallower slope (flatter attenuation) was correlated with higher perceived music quality ratings. Achieved attenuation decreased in the coupler when the probe tube was inserted into the manikin, suggesting HPD seals were compromised by the probe tube. Consistent with the manikin data, attenuation in human ears was greater when measured using REAT, suggesting similar compromise of the HPD seal during MIRE tests. To assure high fidelity HPDs are well fit, REAT testing is recommended to verify both overall attenuation and flatness of attenuation in individual listeners.
Scaleable production of microbubbles using an ultrasound-modulated microfluidic device
Authors: Messaoudi Walid , Carugo Dario , Stride Eleanor P.
Published: December 2020

Surfactant-coated gas microbubbles are widely used as contrast agents in ultrasound imaging and increasingly for therapeutic applications. It has been shown that the acoustic response of microbubbles is determined by their size and coating properties and hence depends upon both their chemical composition and the manufacturing technique used to produce them. We have previously presented a hybrid device consisting of a simple microfluidic T-junction with an integrated ultrasound transducer that provides superior production rates and microbubble stability compared with conventional microfluidic systems but with significantly better microbubble uniformity than standard emulsification techniques. The maximum production rate was, however, still limited compared to industrial methods. In the present study a new device was developed that enables production of >108 microbubbles per second using a single device with a mean bubble diameter of 1.4 μm without degrading microbubble uniformity. Production rates of >109 microbubbles per second can be achieved through parallel operation of multiple channels within a single device; comparable with bulk emulsification butwithout the risk of contamination and/or degradation of sensitive components.
Acoustic radiation force acting on a heavy particle in a standing wave can be dominated by the acoustic microstreaming
Authors: Pavlic Alen , Baasch Thierry , Dual Jürg
Published: December 2020

When an acoustic wave scatters on a particle the acoustic radiation force and the microstreaming appear as non-linear time-averaged effects. Although they appear simultaneously, the microstreaming, which is driven by viscous losses, is often neglected in the theoretical modeling of the acoustic radiation force. Here, we investigate the contribution of the acoustic microstreaming to the acoustic radiation force acting on a small elastic spherical particle placed into an ultrasonic standing wave [T. Baasch, A. Pavlic, and J. Dual, Phys. Rev. E 100(6), 061102 (2019)]. The compressible Navier-Stokes equations are solved up to second-order in terms of the small Mach number using a finite element method. Our study shows that above a certain viscosity, when the viscous boundary layer thickness to particle radius ratio is sufficiently large, the contribution of the microstreaming dominates the acoustic radiation force and defines the stable position of the particle, provided that the particle is sufficiently dense. In such cases (e.g., combination of a copper particle of 1 μm radius in a mineral oil), our theory predicts migration of the particle to the pressure antinode.
Effects of hearing aid processing on speech intelligibility in virtual restaurant settings
Authors: Ellis Gregory M. , Souza Pamela E.
Published: December 2020

Hearing-impaired listeners struggle to understand speech in complex environments like restaurants. Environmental factors (signal-to-noise ratio and reverberation time) and hearing aid processing (digital noise reduction and wide dynamic range compression [WDRC]) have been shown to affect speech intelligibility in these contexts. We examine the independent and synergistic effects of these environmental factors and processing strategies on speech intelligibility. Virtual space techniques were used to build a virtual restaurant. The target talker was located directly in front of the listener and competing talkers were located to the listener’s right in various positions around the restaurant. Signal-to-noise ratio was varied randomly, centered on 0 dB with a standard deviation of 2 dB. Reverberation time was either 0.8 or 1.8 s. Hearing aid processing was simulated using custom software. WDRC was either fast or slow with the following attack/release times: 5/50 ms and 100/2000 ms. Digital noise reduction was either on or off. Customized gain and frequency shaping were applied to the signals. Listeners heard low-context sentences through insert earphones and repeated the target sentence. Responses were scored based on the number of correctly repeated keywords. Preliminary results show that the effect of WDRC depended on reverberation time. [Work supported by NIH.]