bluuebunny/crossref_metadata_2025 huggingface dataset:
Indexing tongue profile narrowing for English lateral consonants using 3D volumetric MR imaging
Authors: Llorens Mairym , Byrd Dani , Vazquez Nancy , Goldstein Louis , Sorensen Tanner , Toutios Asterios , Narayanan Shrikanth S.
Published: November 2017

Production of lateral consonants in many languages involves separate but coordinated tongue tip and tongue rear actions—raising of the tongue tip and retraction of the tongue body. Given these gestures and the presence of lateral airflow, it has been speculated that horizontal (i.e., side-to-side) narrowing of the tongue may occur during production of these laterals, either as a passive result of the anterior-posterior lingual stretching or as an actively controlled movement. This study uses 3D volumetric MR scans of speakers producing a variety of sustained English sounds to examine horizontal tongue width as a function of consonant laterality/centrality and as a function of vowel height in front vowel contexts. Multiplanar reconstruction of volumetric data for each token and subject permitted imaging of the static postures on the axial plane. We determine a protocol for identifying a specific oblique axial slice in terms of mid-sagittal anatomical landmarks that allows for a stable and informative index of horizontal tongue width. This index demonstrates utility for identifying and quantifying tongue profile narrowing specific to English lateral consonants. [Work supported by NIH.]
Onset f0 as a correlate of voicing in Marathi
Authors: Dmitrieva Olga , Dutta Indranil
Published: November 2017

Onset f0 (the fundamental frequency at the onset of vowel immediately following the consonant) has been shown to correlate with voicing in a variety of languages with two-way voicing contrasts in stop consonants, such as the voice-type contrast (between prevoiced and voiceless unaspirated stops) or the aspiration contrast (between voiceless unaspirated and voiceless aspirated stops). Onset f0 is typically higher after phonologically voiceless than after voiced stops. With some notable exceptions, onset f0 data from languages with three-way and four-way voicing contrasts is relatively scarce. The present study explores onset f0 as a correlate of voicing in Marathi, an Indo-Aryan language with a four-way voicing contrast which includes both aspirated and unaspirated voiced and voiceless stops. Results demonstrate that onset f0 covaries with both laryngeal voicing and aspiration in Marathi: f0 is significantly lower for both sets of voiced than voiceless stops. Onset f0 is also significantly lower for both sets of aspirated than unaspirated stops but the effect of voicing is greater in magnitude and more consistent across individuals than the effect of aspiration. Combined with previous findings, the data suggest that onset f0 covariation with laryngeal voicing is more universal across languages than its covariation with aspiration.
Acoustical research and publications of Chester McKinney
Authors: Muir Thomas G.
Published: November 2017

Chester McKinney and his students and colleagues began publishing on acoustics research in the early 1950s, in The Journal of the Acoustical Society of America, The Journal of Underwater Acoustics, and in numerous proceedings of symposia dealing with high resolution sonar for mine hunting. Much of his work involved official studies on major issues, done for and published by the U.S. Navy. A number of his lectures to lay audiences addressed timely topics pertaining to contemporary topics, such as the conduct of classified research on university campuses. He was noted for excellent tutorials and fascinating historical perspectives. Some of Chester's publications are briefly discussed here, including his Journal publications on transduction with reflectors, the transition between near and far-field radiation, the target strength of geometric objects and the discovery of creeping or circumferential waves in echoes. [Work supported by Applied Research Laboratories, the University of Texas at Austin.]
Possible path for speech privacy design and performance approaches
Authors: Roy Kenneth P.
Published: November 2017

Speech privacy (or the lack thereof) is becoming a well-defined issue relating to “acoustic comfort” as a factor in building IEQ. This is the case for commercial offices as well as for healthcare spaces. The drivers for this include worker productivity, and confidentiality of sensitive information. CBE (Center for the Built Environment, UC Berkeley) surveys show the lack of speech privacy as being the most significant factor in disapproval of building IEQ for “green rated,” and for all other building types. Healthcare regulations such as HIPAA and HCAHPS are transforming the design of hospital facilities and procedures in part due to oral privacy and annoyance issues. The “WELL Building Standard” is going beyond LEED to consider the occupants health and productivity as affected by the IEQ. ASHRAE is going beyond “high performance green buildings” to now include an IEQ Global Alliance. So, where are we going with all this work?? Well, the metrics and measurement procedures used to measure and define levels of speech privacy are being updated at ASTM International to provide a basis for evaluation of speech privacy in both open plan and closed plan, and combinations thereof. This work will be outlined herein.
The emergence of a new pronunciation variant in a culturally changing appalachian community
Authors: Jacewicz Ewa , Fox Robert A.
Published: November 2017

The dialect spoken in the small southern Appalachian community in Western North Carolina, formally a part of the Inland South, represents the most archaic features of Southern English, including monophthongization of the diphthong /ai/ to [a:]. While Southerners produce the monophthong before voiced consonants (“prize”) all across the South, pre-voiceless monophthongization (“price”) is more restricted and still occurs in the Inland South. However, as the local culture is gradually shifting toward new mainstream sociocultural norms, so does the local dialect. To document the sound change in progress, this acoustic study examined the /ai/-monophthongization across several generations of local speakers ranging from 8 to 91 year olds, 58 males and 60 females, using a style shifting paradigm. Older generations produced the monophthong irrespective of speaking style and consonant context. Young adults introduced the diphthongal variant in pre-voiceless context. The actual departure from the monophthong occurred in children—more so in the girls—who created an intermediate, slightly diphthongized variant of /ai/, halfway between [a:] and /ai/. Bridging the two worlds, the children adjusted their pronunciation of this intermediate diphthong according to speaking style, also rejecting the archaic pre-voiceless monophthongization. Strategies for children’s association of the spectral enhancement/reduction with communication context will be discussed.
Incipient /ay/-Raising in Baton Rouge
Authors: Berkson Kelly , Herd Wendy
Published: November 2017

Canadian raising targeting the /ay/ diphthong has been reported for a number of dialects of U.S. English. In the United States and elsewhere, however, the incipient—or purely phonetic—stage of diphthong raising, wherein it is triggered only by consonants that are phonetically voiceless, has been notoriously difficult to capture. In such a stage, raising is expected before the /t/ in cite (/saɪt/ → [sʌɪt]) but not before the flapped-/t/ in citing (/saɪtɪŋ/ → [saɪɾɪŋ]). Berkson, Davis, and Strickler (in press) recently discovered incipient phonetic raising in northeastern Indiana, however, and have suggested that extremely short diphthongs immediately preceding a primary stress (as in citátion, psychólogy) may be the very first to undergo raising. We investigate this hypothesis with data from Louisiana. While Yat English spoken near New Orleans has been reported as an /aw/-raising dialect (Carmichael, 2012), we also find /ay/-raising in New Orleans. Furthermore, the question of whether raising is present in Baton Rouge remains unanswered. Data presented here reveal that incipient phonetic raising is present in some—but not all—talkers from Baton Rouge. We consider the variation in Baton Rouge /ay/-raising in the context of gender differences and of /ay/-monophthongization typical in Southern varieties of English.
Acoustic correlates of perceived southernness ratings
Authors: Gunter Kaylynn , Vaughn Charlotte , Kendall Tyler
Published: November 2017

The Southern U.S. dialect and the Southern Vowel Shift (SVS), in particular, have been the subject of extensive research (e.g., Feagin, 1986; Labov, 1991; Fridland & Kendall, 2015), though there is limited work examining what acoustic cues trigger listeners to judge a speaker as sounding southern (cf. Fridland, Bartlett, & Kreuz, 2004; Allbritten, 2011). Fridland & Kendall (2012), and others, have used the Euclidean distance (ED) between the front vowels /e/ and /ɛ/ as a gradient metric of speakers’ degree of SVS shiftedness. While this was demonstrated to be a useful diagnostic in production, it has not been tested against listeners’ percepts of speakers’ southerness. This study asks: are listeners’ perceptions of southernness predicted by a speaker’s /e/-/ɛ/ ED, or other such measures? To test this question, we presented listeners with isolated words from both southern and western speakers. Listeners rated words on a 1–9 scale of how southern they sound. We assess whether southernness ratings are predicted by speakers’ /e/-/ɛ/ ED and other acoustic correlates. We examine both the perception of vowels implicated in the SVS, in addition to those less associated with the shift. Results shed light on the acoustic correlates of perceived southernness in vowel production.
Pitch accents in read speech: Black and White southern women
Authors: Holt Yolanda F. , Rangarathnam Balaji
Published: November 2017

Prosodic variation between African American English and General American English has been attested to in numerous works, yet few studies have collected measures of F0 in African American English and fewer have examined F0 beyond the word level. Additionally, the analysis of prosodic variation in regional dialects of American English is not well studied. F0 movement at the level of the Intonational Phrase (IP) is known to convey both local and global information. Research on F0 movement in General American English has analyzed combinations of H(igh) and (L)ow pitch accents as categorical markers of prosodic alignment to the segmental string. Understanding the alignment of F0 contours provides key information on phonetic realization and phonological alignment in the creation of intonational categories. This pilot data explores the interaction of F0, vowel duration and word duration of prenuclear and nuclear pitch accents in the read speech of Black and White southern women. This study seeks to determine if group differences exists in the expression of pitch accents between the regionally defined socio-ethnic dialects used by the two groups. Results will be discussed in terms of dialect variation.
Flapping before a stressed vowel: The case of whatever
Authors: Shport Irina A. , Johnson Gregory , Herd Wendy
Published: November 2017

In English, word-internal intervocalic alveolar stops are predominantly flapped when preceding an unstressed vowel (water, charity) and optionally flapped at word boundaries preceding unstressed and stressed vowels (that is, private airplane). In this study, we show that /t/ is flapped in whatever although it is word-internal and precedes a stressed vowel. The data were elicited in a sentence reading task, with four speakers of Appalachian English. The duration of /t/ and the acoustic correlates of stress were examined. A comparison of vowel duration and amplitude patterns in whatever versus everwhat (both words are relative pronouns in free relative clauses in this dialect, N = 699) showed that the second syllable is stressed in whatever. A comparison of /t/ durations showed no significant differences among whatever, watermelons, waterlilies, water buffalo (N = 533, M = 30.1 ms). These results may be interpreted as: (a) whatever is an exception to the word-internal flapping environment, or (b) the word-internal flapping environment must be modified to include preceding stressed vowels at morpheme boundaries, or (c) whatever consists of two phonological words and falls within the word-final flapping environment. Prosodic and syntactic analyses of free relative clauses consistent with the last interpretation are discussed.
Tailoring the flow of acoustic waves by architectured metamaterials
Authors: Fang Nicholas X.
Published: November 2017

Today, sound is an indispensable component in numerous industrial and consumer products, such as musical instruments, cars, building technology, medical diagnostics, and many others. Acoustic characteristics are among their most important properties, greatly influencing their function and our society at large. Recent development of acoustic metamaterials opens a door to an unprecedented large design space for acoustic properties such as negative bulk modulus, negative density, and refractive index. These novel concept expands paves the way for the design of a new class of acoustic materials and devices with great promise for diverse applications, such as broadband noise insulation, sub-wavelength imaging and acoustic cloak from sonar detection. In this invited talk, I will present our development of advanced design and micro/nanofabrication techniques, to enable exploration architectured meta structures for acoustic waves. These structures show promise on focusing and rerouting ultrasound through broadband metamaterials. As example, our study on the sound absorption of thin composite aerogel foams using a bimodal porous structure predicts a possible route to perfect thin film absorber by increasing the amount of epoxy resin. In a second case, bifunctional acoustic lens can be implemented in practice with subwavelength unit cells exhibiting effective anisotropic parameters. Lastly I will report our study on a prototype hydraulic hydrogel actuators with excellent optical and sonic transparency.
Low frequency ambient noise modeling in the North Pacific: Simulation versus experiment
Authors: Farrokhrooz Mehdi , Wage Kathleen E.
Published: November 2017

Farrokhrooz et al. [J. Acoust. Soc. Am., 2017] measured the seasonal variations of ambient noise in the 40–50 Hz band using long vertical arrays deployed during SPICEX, a 2004–2005 experiment in the northeastern Pacific. This talk compares simulations of low frequency noise from distant sources with the SPICEX data. The dominant sources of distant noise in the 40–50 Hz band are ships and wind. Noise from surface shipping and wind sources is transferred into the deep sound channel by several mechanisms [Dashen and Munk, J. Acoust. Soc. Am. 1984] and propagates long distances. The simulations use shipping density maps from exactEarth, Ltd., and measured wind speeds from European Centre for Medium-Range Weather Forecasts (ECMWF). A parabolic equation model that includes internal wave effects is used to generate Monte Carlo trials for different realizations of the shipping and wind environment. Results indicate that the seasonal variations in the SPICEX data are dominated by distant wind sources, including storms and persistent high latitude winds during the winter season. This comparison of simulation and experiment supports Bannister’s conclusions [J. Acoust. Soc. Am., 1986] regarding the role of high latitude winds in generating low frequency ambient noise. [Work sponsored by ONR.]
High-resolution spectral-element computation of underwater noises due to offshore piling
Authors: Manalaysay Arvin , Jeong Chanseok , Gharti Hom Nath
Published: November 2017

Offshore piling has been effective in building foundations of offshore structures, such as wind turbines, bridges, and oil rigs. Despite such merits, underwater noise due to offshore piling is considered to be its critical setback. Pile driving creates a high-level underwater sound that harms marine ecosystems. There have been studies that successfully predicted these noises by using numerical methods, for example, Finite Element Method (FEM). However, there has been no FEM study that considers anti-symmetric irregular domains and complex bathymetry to compute underwater noises in the high-frequency range (>1000 Hz) due to expensive computational costs of FEM. To bridge the gap, this work attempts to explore a novel, powerful simulation tool to efficiently obtain offshore piling noises in complex settings and in the high-frequency range. We adopted and modified an open-source large-scale parallel Spectral Element Method (SEM) wave simulator, SPECFEM3D. SEM is known to be much more efficient than FEM for wave propagation analysis problem of a very large number of elements and time steps without compromising accuracy. Our computational method can be used for prediction of offshore piling underwater noise and investigating novel piling methods, such as optimized shapes of piles or air bubbles curtains to mitigate underwater noise.
The interactive multipurpose performing arts hall
Authors: Paek Hyun , Siebein Gary W. , Miller Jennifer R. , Roa Marylin , Vetterick Matthew
Published: November 2017

Each multipurpose performing arts hall has a unique acoustic signature. The success of a modern multipurpose hall relies on how the disciplines of architecture, interior design, stage lighting and rigging systems, and acoustical design are coordinated to very small tolerances. The shaping and finish materials are integrated both visually and with precision to create the sound field of the room to accommodate a variety of venues. Two case studies are presented. The first is a 1000 seat multipurpose performance hall in central Florida which accommodates the use of variable acoustics, a specially designed orchestral shell, stage lift, and all visible interior spaces sculpted to provide richness of both amplified and natural acoustics. The second is a performance hall for a magnet high school for the performing arts in western Georgia that has undulating waves of aesthetically integrated panels on the walls that provides a stunning multipurpose space even with economic constraints. The case studies present different approaches to acoustical design of multipurpose theaters. The first multipurpose theater accommodates the needs of varying visiting performers while the second case study focuses on the presentation of students of performing arts that needed an economical but aesthetic center piece of a magnet school. This interactive process between the design team ultimately results in the beauty of the interactive participation of the audience and the performers also.
Trends in performing arts center design
Authors: Hagler Jack P.
Published: November 2017

The world of performing arts continues to evolve. Audiences have changed. With every show, contemporary live entertainment delivers an updated, but still unique, experience. Operas of the 18th century are the Broadway shows of the 21st century. Orchestras of the 1700s are the Thievery Corporation of today. Lillie Langtry is now Lady Gaga. Performing arts centers must embrace the concept of popular entertainment inside and outside of the audience chamber to keep audiences excited, engaged, and attending. Contemporary entertainment attracts a contemporary audience—a technology-driven generation with a new set of expectations when it comes to a night at the theatre. Here are trends we’ve observed in our practice. Convertible audience rooms and floors for more versatility and flexibility; PAC reputation, space utilization, and the decline of attendance for classical symphony orchestra programming; audience immersion; creating a more social experience in the audience chamber and beyond; making a night (and day) of it with better food and beverage offerings; safety, security, and the new norm; animation of architecture. This is a discussion of the shift paradigm of performing arts centers from the classic arts to the contemporary arts and how the acoustician might respond to these contemporary trends.
Jazz: Multipurpose art form meets multipurpose space
Authors: Delli Paoli Evan
Published: November 2017

The contemporary multipurpose performance space is not one that can exist without its evolution from Ancient Greek Amphitheaters to Elizabethan theaters to roaring twenties Movie Palaces. Its accelerating trajectory and relevance are directly correlated to the evolution of the art forms taking place and unfolding from within them. One such art form is Jazz. This session will explore episodic moments throughout the history of the Jazz art form that draw parallels to pivotal moments in the evolution of multipurpose performance spaces as we know them. The session is organized around five specific case studies: (1) Dixieland and The Rise of Armstrong; (2) Ellington, The Jazz Orchestra, and The Music Halls; (3) Miles: Birth of the Cool, Bitches Brew and Jazz Reinvention; (4) Gillespie and the melting-pot of Afro-Cuban Jazz; and (5) Jazz Fusion and found space. In each case study, a moment in Jazz history will be used as an analogy to introduce the architectural and acoustic concepts specific to a particular typology of multipurpose space—accompanied by a specific built building project example of how these concepts physically manifest themselves.
Hybridization of performance venues
Authors: Pautz Wendy , Adams Julie
Published: November 2017

It should come as no surprise that the future of the performance space is wedded to changing demographics and increasingly pluralistic artist expression. New models are needed to survive the rapid societal change—socially, culturally, and economically. While multi-purpose functionality has long since become the norm for both civic and community arts venues, we are now seeing the advent of hybrid civic facilities—venues that serve other forms of public gathering to complement arts programming. This proposition entails rethinking performance venue typologies at a fundamental level to ensure a sustainable future. From the multiple perspectives of a diverse panel of industry experts, this session will explore the underlying factors that shape current and future venue trends, including capacity to serve a wide range of artistic content as well as other civic and community programming. The following project case studies will be examined as reference points to the discussion: The Tobin Center for the Performing Arts, San Antonio Federal Way Performing Arts and Event Center, Federal Way, Washington Octave 9 (experimental performance venue under development for the Seattle Symphony Orchestra) Audience engagement and spirited dialogue around this topic is encouraged and expected!
Biosonar gain control in odontocetes: Evoked-potential studies
Authors: Nachtigall Paul E. , Supin Alexander
Published: November 2017

The biosonar of odontocetes processes echo signals with a wide range of echo levels. Several mechanisms that serve to compensate for the echo-level variation (biosonar gain control) have been revealed: (1) the adjustment of the emitted sonar pulse levels (the longer the distance to the target, the higher the level of the emitted pulse), (2) the release from forward masking of the echo by the preceding self-heard emitted pulse (the longer the distance to the target, the more release of the echo-response from masking), and (3) an active control of hearing sensitivity (the lower the echo level, the higher the sensitivity). Investigations using the auditory evoked potential technique have demonstrated that these processes manifest different aspects of the functioning of a common gain-control system. The control of the emitted sonar pulse level does not change the echo-to-emitted pulse ratio but makes forward masking able to function at various target distances. The active control of hearing sensitivity also adjusts forward masking to function at various target distances. These combined processes are capable of producing an effective reduction in the variation of the level of the response to the echo when the target strength and target distance vary within a wide range
Echo jitter delay discrimination in bottlenose dolphins (Tursiops truncatus)
Authors: Mulsow Jason , Finneran James J. , Houser Dorian S. , Jones Ryan
Published: November 2017

Experiments with bats show echo delay discrimination capabilities on sub-microsecond scales, which is an acuity that is much higher than that predicted by the auditory nervous system’s ability to directly encode high-frequency phase information (i.e., through neural phase locking). To provide a cross-species comparison, echoic discrimination experiments were conducted with two bottlenose dolphins. Dolphins were trained to echolocate a “phantom” target and report a change from a target with a static delay of ~12 ms to one with alternating delay, or “jitter,” imposed on the static delay. Performance was measured as a function of jitter delay. Both dolphins were able to reliably detect jitter down to ±1 μs, although lower amounts of jitter were not detected. When the jittered echo was phase shifted by 180° relative to the static echo, performance was near 100% at all jitter delays, including ±0 μs. Both dolphins utilized intermittent patterns of click emissions, which were unusual for the relatively short ranges employed. Bottlenose dolphins do not appear to possess the sub-microsecond delay acuity capabilities observed in some bats. However, the current results suggest that dolphins can encode information resembling echo phase information in determining target range. [Funding from ONR.]
Dynamic representation of 3D auditory space in the midbrain of the free-flying echolocating bat
Authors: Kothari Ninad B. , Wohlgemuth Melville , Moss Cynthia F.
Published: November 2017

Our natural world is three-dimensional. A fundamental requirement of spatial orientating behaviors in the natural environment is the representation of 3D sensory space. Despite the importance of 3D sensory coding of a natural scene to guide movement, most neurophysiological investigations of this problem have been limited to studies of restrained subjects, tested with 2D, artificial stimuli. Here we show for the first time that auditory neurons in the midbrain superior colliculus of the free-flying echolocating bat encode 3D egocentric sensory space, and that sonar-guided inspection of objects in the environment sharpens spatial tuning of single neurons. Combining wireless multichannel neural recordings from free-flying bats, synchronized with video and audio data, and an echo model that computes the flying animal’s instantaneous, stimulus space, we demonstrate 3D echo-evoked receptive fields of single auditory midbrain neurons in animals orienting in a complex environment. We discovered that the bat’s active sonar inspection of objects dramatically tightens range tuning of single neurons and shifts peak activity to represent closer distances. Our research demonstrates dynamic 3D space coding in a freely moving mammal engaged in a real-world navigation task.
Core and resonance logger (CARL) measurements of fine-grained sediments containing infauna
Authors: Venegas Gabriel R. , Lee Kevin M. , Ballard Megan S. , McNeese Andrew R. , Wilson Preston S. , Dorgan Kelly M.
Published: November 2017

Benthic infauna perform important ecological functions such as water filtration, the recycling of organic matter, and forage for larger predators. However, how infauna affect bulk acoustical properties of the sediment is less studied and warrants further investigation. During a field experiment conducted in Petit Bois Pass, AL, multiple cores of fine-grained sediments containing infauna were collected by divers and analyzed using a core and resonance logger (CARL). CARL is a core-logger capable of performing both conventional pitch-catch measurements radially along the core as a function of depth and lower frequency resonance measurements. Resonance measurements were performed by exciting acoustic modes within the core and sensing them externally along the core’s length. By utilizing both pitch-catch transducers as receivers, symmetric and asymmetric modes can be identified, and sound speed can be inferred as a function of frequency. The frequency ranges for the pitch-catch and resonance measurements were 100 kHz to 400 kHz and 15 kHz to 30 kHz, respectfully. Subsequently, the cores were sectioned and were either sieved for infauna or analyzed for porosity and grain size distribution. The measured sound speeds will be compared with biological and geological properties of each individual core. [Work supported by ONR.]
Sediment characterization using normal-incidence echo sounding in a biologically active environment
Authors: Isakson Marcia J. , Rukavina Michael , Owens Johanna
Published: November 2017

In collaboration with the Dauphin Island Sea Lab, normal-incidence acoustic measurements were taken in the Petit Bois Pass which is know to harbor benthic biology such as tube worms. The acoustic system used is easily deployed from a small craft and self-calibrating. The acoustic measurements were taken coincidentally with grab samples to characterize both the sediment type and the types of benthic biology. Data were also collected in an area void of benthic biology for comparison. These measurements were analyzed to assess the ability of normal-incidence measurements to determine sediment type in the presence of benthic biology and also to develop methods for characterizing benthic biology with acoustics. [Work sponsored by ONR, Ocean Acoustics.]
Acoustical characterization of a seagrass meadow in the Lower Laguna Madre
Authors: Ballard Megan S. , Lee Kevin M. , McNeese Andrew R. , Sagers Jason D. , Wilson Preston S. , Rahman Abdullah F. , Dubin Justin T. , Venegas Gabriel R.
Published: November 2017

This talk presents preliminary results from an experiment conducted in the Lower Laguna Madre, Texas to characterize the physical and acoustical properties in a meadow of Thalassia testudinum. Concurrent measurements were collected using (1) acoustic probes, (2) side-scan and parametric sonar, (3) broadband propagation, and (4) sediment cores. The acoustic probes provided localized, direct measurements of sound propagation in the seagrass canopy as well as geoacoustic properties (compressional and shear wave speed and attenuation) of the seagrass-bearing sediment. The side-scan and parametric sonars were used to survey for seagrass abundance and sub-bottom layering. Broadband signals produced by a combustive sound source were recorded at several ranges by hydrophones and geophones and were used to infer geoacoustic properties of the seagrass and underlying sediment for rapid environmental assessment. The sediment cores were analyzed in the laboratory using both low-frequency resonator measurements and high frequency travel-time measurements to estimate compressional wave speed, after which they were sectioned and measurements of sediment grain size, porosity, and biomass were obtained. The combination of these data sets provides a unique characterization of the geoacoustic properties of a seagrass meadow. [Work sponsored by ARL:UT IR&D and ONR.]
Application of laser ultrasound technique to evaluate wave velocity in bovine meniscus
Authors: Sakata Yoshitaka , Mori Shunki , Kawase Mami , Matsukawa Mami
Published: November 2017

In vivo elasticity evaluation of meniscus and cartilage is necessary to understand the condition of the joint. Ishihara et al. have used the photoacoustic method with an endoscope.1 Another possible technique is the laser ultrasound. Making use of the thermoelastic effect, we can stimulate a short longitudinal wave by irradiating the pulsed laser beam to the material. This technique enables noncontact measurements. As an initial study, we have measured the longitudinal wave velocities in a bovine meniscus sample using a pulsed laser (COHERENT Helios 1064-5-50). The meniscus samples were obtained from the knee joint of a bovine femur. The sample size was 4.00×6.50×6.00 mm3. We could excite short longitudinal waves around 30 MHz and measure wave velocities propagating in three directions (bone axis, posterior-anterior, and medial-lateral). The excited ultrasonic wave propagated through the meniscus sample and was received by a piezoelectric sensor. The velocity range was about 2950 m/s–3450 m/s, showing the highest velocity in the anterior-posterior direction. Velocities also depended on the water content and showed small heterogeneity. [1] M.Ishihara et al., Jpn. J. Appl. Phys. 42, 556–558 (2003).
Modeling of the acoustic radiation force in elastography
Authors: Prieur Fabrice , Sapozhnikov Oleg A.
Published: November 2017

Elastography is a non-invasive imaging technique that can assess in vivo tissue stiffness. Shear wave elastography imaging uses the acoustic radiation force (ARF) to produce shear waves. Numerical models rely on different formulations of the ARF. We present three existing formulations for the ARF: its full expression in the second-order approximation and two simplified formulations using a quasi-plane wave and an attenuated plane wave approximation. Analytical expressions for the ARF are derived for the special cases of a spherical concave source and for a quasi-Gaussian beam. They show discrepancies between the different formulations. For strongly divergent or highly focused beams the result from the second-order approximation differs from both simplified formulations. However the second-order and quasi-plane wave approximations create identical shear displacements. The k-Wave simulation package is used to compute the ARF and the ensuing transient displacement produced by an ultrasound probe. The second-order approximation and the quasi-plane wave approximation give different forces but identical displacements. The results using the plane wave approximation significantly differ. It is concluded that for highly focused transducers only the second-order approximation accurately estimates the ARF. For estimating shear displacements the second-order or quasi-plane wave approximation are equivalent and preferable to the plane wave approximation.
A novel coding scheme and its application to ultrafast ultrasound imaging
Authors: Zhang Yang , Guo Yuexin , Lee Wei-Ning
Published: November 2017

Ultrafast ultrasound imaging using plane or diverging waves, not focused beams, has enabled quantitative assessment of biological tissue elasticity, kinematics, and hemodynamics beyond anatomical information in the past decade. However, its sonographic signal-to-noise ratio (SNR) and penetration depth are limited by insufficient energy delivery under safety limits. We hereby propose a novel coding scheme and apply it to ultrafast ultrasound imaging to increase the SNR without compromising the spatial resolution and frame rate. In our coded ultrafast ultrasound imaging scheme, each transmit is a long pulse containing N (N = 2k, k = 0, 1, 2,…) waves with short time intervals and polarity coefficients of + 1 or −1, instead of the conventional short pulse with single wave. In reception, a linear decoding scheme comprised of addition, subtraction and delay operations is devised to recover N times higher intensity backscattered signals to gain SNR of 10·log10(N). Experimental results acquired by the Verasonics Vantage system from the calibration phantom and in vivo human back muscle show that the proposed method using two transmits of N = 32 waves achieves 13.0 ± 0.5 dB SNR improvement at 40 mm depth at 4000 frames/sec, leading to better image contrast and larger penetration depth.
Etiology of the color Doppler ultrasound twinkling artifact on in situ human kidney stones
Authors: Simon Julianna C. , Dunmire Barbrina , Cunitz Bryan , Sapozhnikov Oleg A. , Thiel Jeffrey , Bailey Michael R. , Holm James R.
Published: November 2017

Hyperbaric pressures of 0.3–10 MPa (absolute) have been shown to reduce the magnitude of the color Doppler ultrasound twinkling artifact on ex vivo human kidney stones, supporting the hypothesis that surface crevice microbubbles cause twinkling. For the first time, we investigate the etiology of twinkling on in situ human kidney stones. Eight human subjects with kidney stones known to twinkle were imaged with a Philips/ATL P4-2 transducer and Verasonics ultrasound system for 45 minutes while inside a hyperbaric chamber. Subjects breathed ambient air while the pressure in the chamber cycled to a maximum pressure of 0.4 MPa, with a scheduled decompression stop at 0.16 MPa where subjects breathed pure oxygen. Preliminary results show no change in the twinkling amplitude at 0.4 MPa compared to the baseline measurements before pressurization; however, a statistically significant increase in the twinkling amplitude was observed when subjects breathed pure oxygen at 0.16 MPa (p = 0.046). The increase in the twinkling amplitude upon changing respiratory gas composition further supports the crevice microbubble hypothesis of twinkling. Higher pressures than explored in this study may be needed to reduce twinkling on in situ human kidney stones. [Work supported by the National Space Biomedical Research Institute through NASA NCC 9-58 and NIH grant DK043881.]
Study of effects of ultrasound stimulation on platelet-like-particle mediated fibrin-network deformation
Authors: Joshi Aditya A. , Seema Nandi , Brown Ashley , Muller Marie M.
Published: November 2017

An important function of platelets is their ability to bind to fibrin. Over time, platelets contract the fibrin network to induce clot collapse through a process known as clot retraction. Synthetic platelet-like particles (PLPs) created from ultralow-crosslinked (ULC) microgels by conjugating ULCs to a fibrin-specific antibody are capable of mimicking this ability of natural platelets to induce fibrin network collapse. However, the rate of clot retraction is low compared to natural platelets. We demonstrate that deformability of a tissue-mimicking phantom containing ULCs increased in presence of ultrasound stimulation. We observe that the deformability of the ULC was optimal for 1MHz stimulation and a 0.025 mg/mL microgel concentration. PLP-laden, ULC-laden, and microgel-free fibrin clots were created and exposed to ultrasound stimulation for a period of 72 hours. The second set of clots was also created and monitored for 72 hours without ultrasound exposure. Clots were imaged via CryoSEM at 24 and 72 hours after polymerization to determine the effects of the PLPs and ultrasound stimulation on fibrin-network collapse. CryoSEM analysis of clots demonstrated increased density and decreased porosity in the fibrin network structure in presence of ultrasound, indicating microscopic clot collapse. These results suggest the potential of combining PLPs and ultrasound stimulation to alter fibrin clot properties and could be used in the future to enhance wound healing outcomes.
Demonstration of synthetic aperture sonar or radar using shallow water waves in a ripple tank with small cylindrical targets
Authors: Kirkwood Kathryn P. , Korman Murray S.
Published: November 2017

In an ideal stripmap synthetic aperture radar SAR or synthetic aperture sonar SAS experiment, a collocated transmitter and receiver array, respectively, generate a linear frequency modulated LFM pulse chirp that (1) reflects off of point-like targets that are placed along a smooth surface in the x,y plane and (2) receives backscattered echoes off the targets. The array (located a height h from the surface) may be towed (SAS) or flown (SAR), or in some airborne acoustic applications placed on a vehicle or track. In the stop and hop approximation waves are transmitted and then echoes vs. times are received and recorded at a point location along the track. At discrete locations along the track a set of N echoes are recorded which are pulse compressed using a correlation process. Using a time correlation backprojection algorithm the echoes are used to predict an image of the targets, namely the two-dimension reflectance f(x,y). Using a ripple tank, point-like spherical pulses are generated at locations guided by a linear track. The echoes from several slender cylindrical rods are received by a linear capacitance-to-voltage converter needle like probe [McGoldrick, Rev. Sci. Inst. 42, 359–361(1971)] and backprojection is performed to predict the target locations.
Sound level impact studies for wind energy in NY State: A whole new world
Authors: O'Neal Robert
Published: November 2017

In 2012, New York State adopted regulations for any energy facility over 25 megawatts in electrical capacity (“Article 10”). Since that time at least 15 wind energy projects have entered permitting, with many of them deep into the required sound level studies prescribed by Article 10. The author is working on seven of these projects and will cover the key steps in the process ranging from the initial public involvement through submittal of an application. The sound studies for Article 10 have become one of the most thorough and complex in the industry. Key elements of the technical studies include multi-season existing condition measurement programs, sound level modeling, meteorological data analysis, literature reviews, regulatory comparisons, and evaluation of a multitude of additional sound-related criteria such as hearing impairment and speech interference. The depth of the sound studies appear to be expanding beyond that contemplated in the Article 10 regulations.
Public acceptance of wind energy: Impact of sound levels
Authors: Haac Thomas R. , Landis Matt , Kaliski Kenneth , Hoen Ben , Rand Joesph , Firestone Jeremy , Pohl Johannes , Huebner Gundula , Elliot Debi
Published: November 2017

Lawrence Berkeley National Laboratory led a survey of 1,729 individuals located within 8 km of utility scale wind turbines in the United States. The survey included respondents around both large and small wind projects throughout the country. The survey focused on social acceptance, procedural and distributional justice, landscape and sound perceptions and annoyance, and compensation. A total of 15 of the wind projects were modeled to estimate the sound levels at each respondent’s home. Modeled metrics included background sound levels, maximum one-hour sound levels, percentage of time the respondent is downwind of a turbine, and a long-term sound level estimate using the local wind project capacity factor. Statistical analyses were conducted to estimate the acoustical drivers (sound level and sound level difference above background) toward the propensity for annoyance, and how these were affected by non-acoustic factors (e.g., compensation, prior attitude toward the project, visibility, etc.).
Human postural sway results in response to audible and infrasound emissions from wind turbines
Authors: Nelson Peggy B. , Byrne Andrew , Waggenspack Matthew , Sullivan Michael , Feist Christopher , Herb William
Published: November 2017

Fifty healthy adult subjects ages 21–73 years attended to audible and infrasound signals generated from a wind turbine, recorded at 600 m and re-created in the laboratory. Stimuli consisted of modulated and unmodulated audible sound at 50 dB SPL, as well as recorded and peak-enhanced infrasound at an overall level of approximately 85 dB SPL (peaks up to 95 dB SPL). Participants were tested for their postural stability, detection, and ratings of audible and infrasound emissions from turbines. They also completed pre- and post-testing surveys for symptoms of imbalance. All subjects were blind to the knowledge that the stimuli were recorded from wind turbines. No significant adverse effects from healthy adults have been noted to date. Some individuals reliably indicated detection of infrasound signals. A few participants indicated mild symptoms (a rating of 1 on a scale from 0 to 4) following the test. Testing of patients who report vertigo will begin soon. Detailed results and implications will be discussed.
Measurements of infrasound blade pass frequencies in the far field
Authors: Metelka Andy
Published: November 2017

Infrasonic BPFs from wind turbines do appear as far as 120 km away from the nearest wind turbine at relatively low pressure levels. Previous papers clearly identify BPFs inside homes showing that they are rotational components of wind turbines. Both seismic ground vibration simultaneous to infrasound pressure are measured in the extreme far field in order to understand transfer paths. Air borne measurements clearly dominate in the far field also indicating audible amplitude modulation has no contribution to BPFs at these distances.
Acoustic compliance with permit conditions—What does it mean?
Authors: Cooper Steven E. , huson les
Published: November 2017

The use of a dBA L90/L95 limit for operational wind farms, that rely upon a regression analysis of wind and noise that is averaged over time, does not relate to complaints of disturbance. The relevance of the wind farm noise contribution versus the true L90 background level versus wind speed, the percentage of time above the nominal permit condition, and the impact of special audible characteristics is discussed.
Preliminary estimates of acoustic intensity vorticity associated with a turbine blade rate
Authors: Dall'Osto David R. , Dahl Peter H. , Piacsek Andrew A.
Published: November 2017

We report on measurements recently made at the Wild Horse wind farm, near Ellensburg, WA, as part of short experiment to evaluate a device sensitive to acoustic particle velocity. Measurements were made at range of approximately 60 m, directly in front of (facing) a turbine, at a height 1.5 m above ground using a sound level meter (SLM) and vector sensor positioned within a few meters of each other. The SLM recorded a steady A-weighted SPL of 58 dB and C-weighted SPL between 70 dB and 84 dB, noting some low-frequency variability due to wind noise. The vector sensor measurement consists of 4 coherently-recorded signals, one from an omnidirectional microphone and three from a tri-axial accelerometer embedded in a lightweight 10-cm diameter sphere, which helps immunize this acoustic particle motion measurement from wind noise. Here we focus on combining velocity and pressure measurements to form acoustic vector intensity. Real (active) and imaginary (reactive) components of this field display temporal properties corresponding to the position of the 3-turbine blades. Time-varying vorticity in the intensity vector demonstrate existence of a signature in wind-turbine noise related to the blade-passing rate (1 Hz) that is not registered with conventional sound level measurements.
Direction of arrival estimation for conformal arrays on real-world impulsive acoustic signals
Authors: Gorman Emily , Bunkley Steven L. , Ball John , Netchaev Anton
Published: November 2017

Current methods for direction of arrival (DOA) estimation are disproportionately represented in the literature by microphone array geometry and sound source properties. A wide array of implemented methods and publications are available for uniformly spaced 2D arrays such as uniform linear arrays (ULA), uniform circular arrays (UCA), and uniform rectangular arrays (URA). Further, implemented DOA estimators are specifically designed for narrowband, continuous signals. Methods applicable to wideband signals on arbitrarily-shaped arrays are limited; alternative approaches that partition the array into sub arrays expand the number of applicable methods. For a realistic military application of a single impulse localization on a conformal microphone array, methods must be able to estimate the DOA of wideband, static, acoustic sources. DOA estimator methods’ performances, capabilities, and limitations are explored on various real-world sound sources and configurations of a five-microphone conformal array.