bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental observations of acoustic backscattering from spherical and wobbly bubbles
Authors: Padilla Alexandra M. , Rychert Kevin M. , Weber Thomas C.
Published: June 2017

Methane bubbles released from the seafloor transport gas through the water column to the atmosphere. Direct or optical methods via underwater vehicles are often used for quantifying methane gas flux in the water column, however these methods are time consuming and expensive. Acoustic measurements, using split-beam and multibeam echo sounders that are readily available on most sea vessels, provide a more efficient method for determining methane gas flux. These acoustic methods typically convert acoustic backscatter measurements of bubbles to bubble size using analytical models of bubble target strength. These models assume that bubbles have uniform shape; however it has been shown that bubbles with a radius greater than 1 mm, which have large Eötvös and/or large Reynolds number, are non-spherical. To investigate the error associated with assuming large bubbles are spherical, a 6 m deep tank experiment was conducted to compare calibrated target strength measurements of both small spherical and large wobbly bubbles to existing acoustic scattering models. Bubble sizes observed in this experiment ranged from a fraction of 1 mm to 6 mm in radius. This experiment used a broad range of frequencies (10-300 kHz) to cover typical echo sounder frequencies utilized in field measurements of natural methane seeps.
Modal active control: A tool to finely adjust the sound of string instruments
Authors: Benacchio Simon
Published: June 2017

Controlling the vibratory properties of musical instruments is an important challenge for musical acousticians, musicians, and instrument makers. The latter try to control these properties modifying mechanical parameters of instruments like their shape or their materials to obtain some expected sound attributes. Musicians also modify the vibratory properties of their instruments to change their sound using mutes, for example. Musical acousticians try to modify these properties because it is an intuitive way to investigate the relationship between the instrument mechanisms and their sound attributes. Inspired by industrial techniques, active control was revealed as a convenient way to answer to the latter goal. Moreover, modal active control is a preferred method for the application to musical instruments since their modal parameters are believed to be good descriptors of their vibratory properties. This study aims at applying modal active control on string instruments. First, the possibilities offered by this technique are presented and experimented on several instruments. Then, examples of the control of specific phenomena are given. Couplings between the soundboard and strings for both a cello and a guitar are controlled to cancel the well-known wolf-note phenomenon for the former and to switch from strong to weak coupling for the latter.
Soundscape design of an open-air concert venue using virtual reality technologies
Authors: Chung Andy , To W. M. , Schulte-Fortkamp Brigitte
Published: June 2017

Hong Kong has two mega-projects underway that include open-air concert venues. One of them is called the Kai Tak Sports Park and another is the West Kowloon Cultural District. As an open-air concert venue will produce amplified music and noise from audience, as well as vehicular traffic noise and crowd noise before and after the concerts, a priori analysis of soundscape and noisescape in the district due to musical events is highly desirable. This paper reviews some noise incidents due to concerts at the Hong Kong Stadium and Chinese operas at other public places. We suggest that virtual reality technologies shall be utilized so that stakeholders can hear the possible soundscape and noisescape at different periods of a musical event during the public engagement.
Soundscapes, social media, and big data: The next step in strategic noise mapping
Authors: King Eoin A. , Punla-Green She’ifa , Genovese Samuel
Published: June 2017

The current state-of-the art in noise assessment involves the development of a strategic noise map to identify areas with excessive noise levels, expressed in terms of a single time-averaged noise indicator. While noise maps yield important information regarding sound pressure levels in a particular space, they do not give any representation of the overall sound quality in that space. A more human-centered approach to noise assessment could be achieved by developing soundscapes as a complementary tool to noise mapping. However, most soundscape studies traditionally use surveys or interviews to assess general sentiment toward the acoustic environment, and as such are generally restricted to small geographic areas, compared to the entire cities considered in noise mapping. Instead of using traditional assessment techniques, this project aims to harness the potential of big data, including, for example noise complaint data or social media chatter related to noise, to better assess public sentiments towards soundscapes. This would yield an unparalleled dataset of public opinions and perceptions of the acoustic environment. Initial results based on an analysis of NYC311 complaints and geo-localized data mined from Twitter are presented.
Some practical difficulties in assessing community response to low-amplitude sonic booms
Authors: Fidell Sanford , Horonjeff Richard , Mestre Vincent
Published: June 2017

NASA Langley Research Center has been engaged for several years in planning tests of public acceptance of exposure to low-amplitude sonic booms that will be created by its Quiet Supersonic Transport (QueSST) X-plane design. Estimation of a dosage-response relationship for the prevalence of high annoyance with sonic booms is a key part of this testing. The need to credibly assess prompt, single-event responses within carpet boom corridors extending along hundreds of miles of flight tracks and their linkage to sonic boom sound levels at respondents' homes is a large part of the challenge of establishing such a relationship. As many as tens of thousands of contact attempts and thousands of completed interviews must be achieved within short time periods. Conventional social survey approaches to measuring cumulative noise exposure and the prevalence of high annoyance in airport environs are ill-suited to such purposes. ADS-B-based, Internet-enabled flight tracking and impulse noise measurement, as well as high speed interviewing methods, are currently under investigation as potential solutions to difficulties in synchronizing interviews with arrival times of shock waves at residences of exposed populations.
Turbulent particle flux measurement with pulse-coherent Doppler sonar
Authors: Hay Alex E. , Conrad Kacie
Published: June 2017

The accuracy of velocity estimates from pulse-coherent acoustic Doppler systems is related to the magnitude, R, of the ensemble-averaged complex pulse-pair correlation. The closer R is to unity, the more accurate the estimate. The accuracy of particle concentration estimates is also related to the value of R but, in contrast, high accuracy requires R to be less than unity, i.e., the amplitudes from individual pulses in an ensemble should be independent, in order to beat down Rayleigh statistics associated with configuration noise. Consequently, when estimating the turbulent component of the particle flux, i.e., the product of the particle concentration and velocity fluctuations, a tradeoff arises between these conflicting requirements for velocity and concentration accuracy. This tradeoff is investigated through a statistical model of sound scattering from particles embedded in idealized turbulence, and laboratory experiments in which particle velocities in turbulent flow are measured both acoustically, via pulse-coherent sonar, and optically, using particle imaging velocimetry.
Passive acoustic mapping of cavitation during shock wave lithotripsy
Authors: Shoar Kya , Lyka Erasmia , Coussios Constantin , Cleveland Robin
Published: June 2017

Passive acoustic mapping (PAM) has previously been used to localize inertial cavitation during high intensity focused ultrasound. Here, this technique has been applied to shock wave lithotripsy (SWL), a non-invasive procedure whereby kidney stones are fragmented. Conventional diagnostic ultrasound probes were used to detect acoustic emissions during SWL. Signals consisted of reverberation sound from the incident shock wave followed, several hundred microseconds later, by emissions from cavitation collapses. Time-gating was used to isolate the cavitation signals, which were then processed using PAM to create spatial maps of the cavitation activity. Experiments in water indicated the spatial resolution was an ellipsoidal volume 5mm long by 1mm wide. Experiments were carried out in ex vivo pig kidneys and it was observed that cavitation was initiated in the region of the focus but moved laterally by up to 10mm and during treatment exhibited a general migration towards the source. These results suggest that PAM can be used as a tool to map the location of cavitation during SWL and has the potential to differentiate cavitation in tissue (that could contribute to injury) from cavitation near the stone which affects comminution. [Work supported in part by NIH through P01-DK43881.]
Sound and shape of pyeongyoung, stone chime and pyeonjong, bell chime
Authors: Yoo Junehee
Published: June 2017

My main research with Tom is about Korean traditional stone chimes, pyeongyoung and bell chimes, pyeonjong which have been allocated as a set of instruments in Korean traditional court music. The vibrational mode frequencies and the frequency ratios of the modes in modern pyeongyoung and pyeonjong have been studied. The modal shapes of stones and bells were mapped by TV holography, by scanning with an accelerometer and animated by STAR. The vibrational mode frequencies and mode shapes of ancient stone chimes are analyzed and their dependence on stone shapes had been studied by using finite element methods. The dependence of mode shapes and frequencies on vertex angle and base curvature suggests that the geometries used in late Chinese bianqing and Korean pyeongyeong may have been selected to give the best sound. Based on the research with Tom, I could extend the study to reconstruct the whangjongeum or scale in Korean traditional instruments. My Korean group have measured frequencies of historical 261 pyeongyeong stones and 236 pyeonjong bells mainly from the 14th to 19th centuries. The frequencies and the frequency ratios of the modes were analyzed by the era of building them.
Robust Hidden Markov Models for limited training data for birdsong phrase classification
Authors: Kaewtip Kantapon , Alwan Abeer , Taylor Charles
Published: June 2017

Hidden Markov Models (HMMs) have been studied and used extensively in speech and birdsong recognition but they are not robust to limited training data and noise. This work present a novel method to training GMM-HMMs with extremely limited data—and possibly noisy—by sharing HMM components and generating more training samples that cover the variation of the models. We propose an efficient state-tying algorithm that takes advantage of unique characteristics of birdsongs. Specifically, the algorithm groups HMM states based on the spectral envelopes and fundamental frequencies, and the state parameters are estimated according to the group assignments. For noise-robustness, prominent time-frequency regions (time-frequency ranges expected to contain high energy for a particular HMM state) are used to compute the state emitting probability. In Cassin’s Vireo phrase classification using 75 phrase types, the results show that the proposed state-tying algorithm significantly outperforms both traditional state-tying algorithms and baseline HMMs in most training conditions (using 1, 2, 4, 8, and 16 samples). Factors such as number of training data, number of shared components, and level of background noise are also studied in this work.
Development of laboratory-based test methods for the comparative evaluation of performance of advanced hearing protection devices
Authors: Argo Theodore F. , Zadler Brian , LeNeave Cortney , Jerding Jennifer
Published: June 2017

Standard acoustic test methods may not fully capture the performance characteristics of advanced passive and active hearing protection devices. Development of new laboratory-based test methods with the ability to discriminate between the performance characteristics of these devices, such as level-dependent or nonlinear effects, without the use of human subjects was undertaken. Measurements of hearing protection device performance with respect to signal quality, sound localization, self-noise, and impulse response were performed. Signal quality and sound localization were both tested using a compact 3D positioning apparatus which gave us directivity information without the use of human subjects or a large hemispherical test fixture. A sound isolation box was used not only for self-noise but also for impulse response measurements. Results of the impulse testing were compared to freefield shock tube results to ensure consistency among methods. This new evaluation methodology, when performed on an array of advanced hearing protection devices, can provide supplemental or alternative performance data for the relative comparison of devices under test. The results allow for distinction between devices based on preferred characteristics, for example, low self-noise and good signal quality favored over better impulse protection. [Research supported by US Army Natick Soldier Research, Development, & Engineering Center.]
Evaluation of noise exposures and hearing loss at a hammer forge company
Authors: Murphy William J. , Brueck Scott E. , Eisenberg Judith , Zechmann Edward L. , Krieg Edward F.
Published: June 2017

The NIOSH health hazard evaluation program evaluated employees’ exposures to high level continuous and impact noise at a hammer forge company. Personal dosimetry data were collected from 38 employees and noise exposure recordings were collected during two visits to the facility. Extensive audiometric records were reviewed and trends for hearing loss, threshold shifts and risk of hearing loss were assessed. The effectiveness of hearing protection devices for hammer forging was evaluated with an acoustic test fixture. A longitudinal analysis was conducted on the audiometric data set that included 4750 audiograms for 483 employees for the years 1981 to 2006. The analysis of the audiometric history for the employees showed that 82% had experienced a NIOSH-defined hearing threshold shift and 63% had experienced an OSHA-defined standard threshold shift. The mean number of years from a normal baseline audiogram to a threshold shift was about 5 years for a NIOSH threshold shift and was about 9 years for an OSHA threshold shift. Overall hearing levels among employees worsened with age and length of employment. The NIOSH audiometric test criteria in addition to OSHA threshold shift criteria to assess threshold shifts could provide an opportunity for early intervention to prevent future hearing loss.
Amplitude-dependent shock wave propagation in three-dimensional microscale granular crystals
Authors: Hiraiwa Morgan , Boechler Nicholas
Published: June 2017

Ordered arrays of elastic spherical particles in contact, often referred to as granular crystals, have been used as a model system for understanding the dynamics of granular media and explored as a type of designer material for acoustic wave tailoring applications. Due to the Hertzian interactions between the particles, granular crystals composed of macroscale particles have been shown to support strongly nonlinear phenomena including shock and solitary waves. In this presentation, we will describe recent progress in our studies of laser-generated shock wave propagation in self-assembled three-dimensional microscale granular crystals, where adhesive forces between the particles play a major role. Specific features studied include the dependence of the shock wave velocities and absorption on excitation amplitude. Dynamic failure processes such as crater formation and spallation are also explored. The experimental measurements are compared with reduced-dimension discrete element model simulations. New understanding of strongly nonlinear phenomena in microgranular media has potential applications to areas including energetic material dynamics, shock mitigation, and ultrasonic wave tailoring.
The contributions of Nathaniel (Nat) Durlach to binaural hearing research
Authors: Colburn H. Steven
Published: June 2017

The important and extensive work of Nat Durlach in the area of binaural hearing will be reviewed. Nat started working on this topic in the context of work on bat sonar processing at Lincoln Laboratories, with an early publication on his hearing modeling in 1960. Nat's thinking about the sonar problem and signal processing in noise led to his long-term interest and work in human hearing, and he joined the Sensory Communications group at MIT in 1963. In addition to his well-known work on the Equalization-Cancellation (EC) model, his important contributions to other binaural hearing models and experiments will be discussed, including work in detection, discrimination, and estimation. Nat's binaural work also allows a consideration of his deep thinking about problems, his approach to modeling in general, and his distinctive style of interacting with other scientists, both young and old. The ongoing impact of Nat's binaural hearing work, his personal example for approaching research, and his deep influence on the personal lives of his students and colleagues continues strongly into the future.
A century of sonar performance prediction
Authors: Heaney Kevin D.
Published: June 2017

Developments in sonar technology went hand in hand with increased scientific understanding of the factors affecting sonar performance The first known reference is from Lichte (Physikalische Zeitschrift 1919) where cylindrical spreading for propagation loss was accounted for in deep water (convergence zone, CZ) propagation. Users of sonar in the 1920s encountered an “afternoon effect”, a temporary dip in performance that occurred during warm summer evenings, was explained in the 1930s by Iselin and Batchelder in terms of vertical temperature gradients in the sea. A significant amount of work occurred in both World War I(Klein 1962, Wood 1965) and World War II to understand, and therefore be able to predict, the capabilities of sonar systems to detect submerged targets. Understanding of sonar performance increased rapidly during WW2 and continued to advance during the Cold War. Advances in the understanding of sonar performance modeling before, during and after the Second World War are described.
Designing a scalable passive acoustics network
Authors: Mann David
Published: June 2017

To realize the potential of passive acoustics to study animal distribution and behavior over large spatial and temporal scales, systems capable of processing acoustic data remotely and transmitting those results to cloud systems are needed. Passive acoustic recorders have been important for allowing researchers to collect large amounts of data over long time periods, but they allow the decision of how to analyze the data to be delayed until after it is collected. Given the availability of inexpensive computing and cloud connectivity, one key challenge in developing a scalable passive acoustics network is deciding what is important to know. A prototype scalable passive acoustics node to detect dolphin whistles and measure sound levels corresponding to fish sounds, boat noise, and snapping shrimp has been developed. The decision was made to bin data over 10 minute periods (e.g., whistles per 10 minutes), and store only small amounts of raw data for quality control. The system takes advantage of recent developments in consumer level Internet of Things (IoT) tools so that the hardware is inexpensive and the cloud system can handle very large numbers of nodes.
Mitigating noise and traffic congestion through measuring, mapping, and reducing noise pollution
Authors: Park Tae Hong , Yoo Minjoon , Shamoon Charles , Dye Christopher , Hodge Stacey , Rahman Asheque
Published: June 2017

Noise is a ubiquitous and omnipresent urban pollutant with serious health issues. This so-called “forgotten pollutant” includes all types of sounds including vehicular noise, barking dogs, music, and human sounds. Mechanical noise, and especially traffic sound, is especially “annoying” as it manifests in a plethora of ways that can be constant, intermittent, or impulsive. We have approached noise mitigation efforts via notions of “you can’t fix what you can’t measure,” “seeing is believing,” machine-aided soundscape listening, and unusually cost-effective, robust, scalable sensor network designs for dense, spatiotemporal soundmaps creation. In this paper we report on updates—Citygram’s recent partnership with IBM and its “Horizon” edge compute system, plug-and-sense sensor network hardware/software, visualizations, machine learning and sensor scaling/deployment strategies—applicable towards capturing road, rail, aircraft, and other types of urban noise agents to improve understanding of urban livability and traffic congestion. This will include discussion of NYCDOT’s noise monitoring strategies to support the NYC Off Hour Delivery Program. We believe that truck delivery-based noise can be significantly mitigated in order make urban, off-hour truck delivery practicable: a key factor in reducing congestion during the daytime and improving safety for pedestrians and cyclists during busy daytime hours in the urban environment.
Characterization of urban sound environments using a comprehensive approach combining open data, measurements, and modeling
Authors: Picaut Judicaël , Can Arnaud , Ardouin Jérémy , Crépeaux Pierre , Dhorne Thierry , Écotière David , Lagrange Mathieu , Lavandier Catherine , Mallet Vivien , Mietlicki Christophe , Paboeuf Marc
Published: June 2017

Urban noise reduction is a societal priority. In this context, the European Directive 2002/49/EC aims at producing strategic noise maps for large cities. However, nowadays the relevance of such maps is questionable, due to considerable uncertainties, which are rarely quantified. Conversely, the development of noise observatories can provide useful information for a more realistic description of the sound environment, but at the expense of insufficient spatial resolution and high costs. Thus, the CENSE project aims at proposing a new methodology for the production of more realistic noise maps, based on an assimilation of simulated and measured data, collected through a dense network of low-cost sensors that rely on new technologies. In addition, the proposed approach tries to take into account the various sources of uncertainty, either from measurements and modeling. Beyond the production of physical indicators, the project also includes advanced sound environments characterization, through sound recognition and perceptual assessments. CENSE is resolutely a multidisciplinary project, bringing together experts from environmental acoustics, data assimilation, statistics, GIS, sensor networks, signal processing, and noise perception. As the project is in launch state, the present communication will focus on a global overview, emphasizing the innovative and key points of the project.
Psychoacoustics in the United Kingdom in the period 1900 to 1950
Authors: Moore Brian C.
Published: June 2017

Much research in psychoacoustics during this period was conducted in the “Psychological Laboratory” in Cambridge (H. Bannister, A. F. Rawdon-Smith) and in Manchester (T. S. Littler, A. W. Ewing). Although Lord Rayleigh had published his influential duplex theory of sound localization in 1907, lingering doubts remained about whether interaural phase could truly be discriminated—rather, it had been proposed that somehow interaural phase differences were converted into interaural intensity differences. Bannister conducted a series of experiments to assess this idea and concluded that “binaural phase differences are appreciated in some manner which is distinct from the appreciation of binaural intensity differences.” Bannister also reported experiments on time-intensity trading in sound localization and reported that sometimes two images were perceived. Rawdon Smith and independently Littler and Ewing studied the phenomenon of auditory fatigue (temporary threshold shift, TTS). They showed that the maximum TTS produced by an intense fatiguing tone occurred for test tones with frequencies well above that of the fatiguing tone, a phenomenon that was repeatedly confirmed in later studies and that has only recently been explained. A common feature of the papers describing this work was a detailed description of the (often ingenious) apparatus that was developed to conduct the experiments.
Measuring speech-in-noise abilities as part of the standard audiometric protocol
Authors: Fitzgerald Matthew , Swanson Austin , Losorelli Steven
Published: June 2017

Many apsects of the audiologic test battery have remained unchanged for decades, and do not assess the real-world communicative abilities of the patient. For example, word-recognition in quiet is the default test of speech recognition, despite difficulties understanding speech in noise being the primary complaint of most patients. Our goal is to adjust the audiologic test protocol to better assess the communicative abilities of the patient. Towards that goal, we are devising a new clinical protocol in which speech-in-noise testing, rather than word-recognition in quiet, is the default speech test in the audiologic test battery. We have data on over 1500 adults, which indicate normal audiometric thresholds with abnormal speech in noise results for many patients. Perhaps more important, our data also suggest that most instances in which word-recognition in quiet is excellent can be predicted with a combination of audiometric thresholds and speech-in-noise abilities. These data have been used to create clinical recommendations in which speech in noise testing becomes the default clinical test, with guidelines for when word-recognition in quiet is likely to have diagnostic significance and should be conducted. Making subtle, but fundamental shifts of this sort in clinical testing may have significant research and clinical implications.
Efficient aliasing-free HRTF representation
Authors: Alon David L. , Ben-Hur Zamir , Rafaely Boaz , Mehra Ravish
Published: June 2017

Previous studies have shown that individualized head related transfer functions (HRTFs) provide improved localization performance compared to generic HRTF filters, and are therefore considered preferable for binaural sound reproduction. However, individualized HRTFs typically require a large number of measurements, which may extend to several hours. Therefore, they are currently unavailable for the vast majority of users. One approach to lower measurement complexity is to reduce the number of HRTF measurements. This approach although simplifies the measurement process, produces spatial aliasing leading to interpolation error away from the measured directions. In this study, a new method for the measurement of individualized HRTFs with a reduced spatial aliasing error is developed. The reduced spatial aliasing error is achieved by incorporating a small number of individualized HRTF measurements with information from a high resolution HRTFs database, which leads to an optimal interpolation process in the sense of minimum mean square error. An experimental investigation is conducted to validate the improved performance of the proposed method.
Tracing ancient soundscapes
Authors: Jordan Pamela
Published: June 2017

What if the most intact aspect of an archaeological site is actually its historic soundscape? How could researchers and visitors learn about a place from sonic “ruins” when the built environment is significantly deteriorated? This paper discusses the case study of Mt. Lykaion, an ancient Greek sanctuary and athletic complex in near-ground-level ruins. Despite these physical conditions, visitors can experience distinct “sound-lines” throughout the site, where conversations can be held across fifty or one hundred meters in certain locations. Ongoing field explorations are attempting to trace these acoustic connections and determine whether they align with the original site layout. A modified impulse response test was employed based on recent architectural and archaeological findings, and the results were recorded using binaural microphones; the methodology and analysis of the recording data will be presented in detail, with rich possibilities for other ancient outdoor landscapes as well as historic sites without a surviving written record or physical trace. Using psychoacoustic metrics such as perceived clarity and loudness for analysis, the recording results demonstrate how sonic relationships may be identified in open-air settings, and presents a new way to visualize how ancient sites may have functioned based on the remains of their original soundscape.
Classification of pelagic fish using wideband echosounders
Authors: Sande Jeroen v. , Quesson Benoit , Beerens Peter , Fassler Sascha
Published: June 2017

The landing obligation for pelagic fisheries was introduced in January 2015 by the European Commission and will gradually be extended to all fisheries in 2019. This regulation follows the trend for sustainable fisheries in Europe and states that all catches must be landed and counted against the quotas. Pre-catch acoustic fish classification can remotely provide information about fish school composition in terms of species and size distribution. This technique has been tested using three commercial wideband transceivers mounted on a commercial freezer trawler. Together, the three SIMRAD EK80 transceivers cover a frequency range of 45 kHz to 260 kHz. Acoustical data was collected for four months during fishing operations in the North Sea and the English Channel. Custom, through-the-sensor image processing algorithms have been developed to perform automatic school detection under severe noise, interference and ship motion conditions. Dynamic Factor Analysis was applied to exploit common trends in the spectra of the species, resulting in classification scores of 95-100% for the set of 38 homogeneous schools of herring, mackerel and horse mackerel. This data set is too limited to draw firm conclusions on potential operational performance. However, since the utilized spectral trends match with theoretical expectation, the approach is promising.
Effects of modifications of the crackle percept in high-amplitude noise on sound quality and statistical metrics
Authors: Swift S. Hales , Gee Kent L. , Neilsen Tracianne B. , Downing Micah , James Michael M.
Published: June 2017

Three methods of altering a waveform that exhibits the crackle percept in high-amplitude noise were previously considered [Swift, Gee, Neilsen, 2014]. Two alterations—expanding shocks and transforming the derivative of the waveform to a Gaussian distribution—were found to eliminate crackle, while a third modification—transforming the waveform pressure to exhibit a Gaussian distribution—did not eliminate the crackle percept. In this paper, a fourth alteration, altering the phase of a crackling signal in the frequency domain in the manner of an all-pass filter in selected frequency bands, is considered and its effects on the crackle percept is compared to the previous methods. In addition to waveform playback, metrics such as skewness of the pressure waveform derivative and loudness and sharpness, along with their time-varying forms, are used in the comparison. [Work supported by AF SBIR.]
Finite element modeling of thermal and shear decay fields around particles in liquids in an ultrasound field
Authors: Forrester Derek M. , Pinfield Valerie J.
Published: June 2017

Ultrasonic multiple scattering models of wave propagation through inhomogeneous particulate media frequently assumed only acoustical interactions between particles, neglecting thermal and hydrodynamic (shear-mediated) interactions. This assumption is, however, only valid at low concentrations of particles where the particle separation distances are large. Each particle has the propensity to have a short-ranged thermal or shear field around it, caused by the acoustic field, and at moderate to high concentrations these can overlap. Our recent work has shown that, in these conditions in the long acoustic wavelength regime, when the shear or thermal wavelengths are similar to the particle radius, the overlapping shear and thermal fields can result in a significant reduction in effective attenuation. The effect can be described as the conversion of compressional waves to shear/thermal waves and back again at particle/liquid boundaries. Herein, we use finite element modelling of single and groups of particles to show the thermal and shear wave fields and the interactions of these fields that lead to the reconversion effect. Thus, we demonstrate the mechanisms of thermo-acoustic and shear-acoustic interaction for various particulate inhomogeneous media[SS1]. [SS1]This is 180 words.
A numerical study on effect of evaporation and condensation of water vapor on acoustic oscillations of a gas parcel with a Lagrangian approach in a thermoacoustic prime-mover
Authors: Yasui Kyuichi , Izu Noriya
Published: June 2017

Acoustic oscillations of a gas parcel in a wet stack of a thermoacoustic prime-mover are numerically simulated with a Lagrangian approach taking into account Rott equations and the effect of non-equilibrium evaporation and condensation of water vapor at the stack surface. A gas parcel gradually drifts to higher and lower temperature side of a stack in traveling-wave and standing-wave prime-movers, respectively, owing to a shift of phase angle of particle’s velocity with a movement of a parcel according to Rott equations even without evaporation and condensation. It is an alternative acoustic streaming in a narrow tube with temperature gradient along a tube. In a traveling-wave prime-mover, the volume oscillation amplitude of a gas parcel always increases by evaporation and condensation, and pV work done by a gas parcel is accordingly enhanced. On the other hand, in a standing-wave prime-mover, the volume oscillation amplitude sometimes decreases by evaporation and condensation, and pV work is suppressed. Presence of a tiny traveling-wave component, however, results in the enhancement of pV work by evaporation and condensation. In other words, thermoacoustic effect is enhanced by evaporation and condensation under most conditions, which is consistent with experimental results.
Sound pressure distribution in natural or artificial human ear canals in response to mechanical ossicular stimulation
Authors: Ravicz Michael E. , Cheng Jeffrey Tao , Rosowski John J.
Published: June 2017

Otoacoustic emissions (OAEs) in the ear canal (EC) are produced by tympanic membrane (TM) and ossicular motion driven by the cochlea. Measurement of OAEs is complicated by nonuniformities in EC sound pressure, which may lead to misinterpretation. Human temporal bones were prepared by removing most of the cartilaginous EC or replacing the bony EC with an artificial EC. The incus was stimulated mechanically through the facial recess by a small piezoelectric actuator to produce TM motion. Sound pressures resulting from broadband stimuli were measured at ~70 locations along the TM surface (Ptm), in the tympanic ring plane 4-6 mm distal to the umbo (Pec), and along the EC axis. Ptm showed considerable transverse spatial variation in narrow frequency bands at frequencies as low as 5 kHz, in contrast to the simpler distribution when sound enters the EC from its lateral end. These transverse variations generally had dissipated at the tympanic ring plane. Longitudinal sound pressure variations along the EC axis were consistent with a simple uniform tube model. The choice of the best location to measure OAEs above a few kHz involves a tradeoff between longitudinal and transverse Pec variations. [Funding: NIDCD R01 DC00194 and MEEI.]
Low cost underwater acoustic localization
Authors: Iscar Ruland Eduardo A. , Johnson-Roberson Matthew
Published: June 2017

Over the course of the last decade, the cost of marine robotic platforms has significantly decreased. In part this has lowered the barriers to entry of exploring and monitoring larger areas of the earth's oceans. However, these advances have been mostly focused on autonomous surface vehicles (ASVs) or shallow water autonomous underwater vehicles (AUVs). One of the main drivers for high cost in the deep water domain is the challenge of localizing such vehicles using acoustics. Here we propose a novel low cost underwater modem design to assist in localizing deep water submersibles. The system will consist of location aware anchor buoys at the surface and underwater nodes. We present a comparison of methods, simulation of the proposed algorithms as well as experimental results, together with details on the physical implementation to allow its integration into a novel deep sea AUV currently in development.
Leveraging big data: How acoustic archives facilitate ecosystem research
Authors: Wall Carrie C. , Anderson Charles , Jech J. Michael , Van Parijs Sofie M. , Hatch Leila , Gedamke Jason
Published: June 2017

The National Oceanic and Atmospheric Administration’s (NOAA) National Centers for Environmental Information (NCEI) has developed archives for the long-term stewardship of active and passive acoustic data. Water column sonar data have been collected for fisheries and habitat characterization over large spatial and temporal scales around the world, and archived at NCEI since 2013. Protocols for archiving passive acoustic data are currently being established in support of the NOAA Ocean Noise Reference Station Network project, and monitoring marine mammals and fish. Archives maintain data, but access to these data is a core mission of NCEI that allows users to discover, query, and analyze the data in new and innovative ways. Visualization products continue to be developed and integrated into the data access portal so that researchers of varying backgrounds can easily understand the quality and content of these complex data. Spatially and temporally contemporary oceanographic and bathymetric data are also linked to provide an ecosystem-wide understanding of the region. Providing access and facilitating the utility of these data for ecoacoustics research are ongoing efforts at NCEI, and would benefit from input from the acoustics community.
Impact of temperature on the size distribution and shell properties of ultrasound contrast agents
Authors: Shekhar Himanshu , Smith Nathaniel , Raymond Jason L. , Holland Christy K.
Published: June 2017

Physical characterization of ultrasound contrast agents (UCAs) is important for their efficacious use in theragnostic applications. The goal of this study was to elucidate the impact of temperature on the size distribution and shell properties of Definity®, an FDA-approved clinical UCA. A Coulter counter (Multisizer IV) was modified to enable size measurements of UCAs at elevated temperatures. The size distribution and attenuation spectrum of Definity® was measured at room temperature (25 °C) and physiological temperature (37 °C), and used to estimate the shell stiffness and viscosity of the agent at both temperatures. The attenuation coefficient of Definity® increased by as much as 5 dB at 37 °C relative to 25 °C. The highest increase in attenuation was observed at 10 MHz, the resonance frequency of Definity®. However, no significant difference was observed in the size distribution of Definity® at 25 °C and 37 °C. The estimated shell stiffness and viscosity decreased from 1.76 ± 0.18 N/m and 0.21 × 10-6 ± 0.07 × 10-6 kg/s at 25 °C to 1.01 ± 0.07 N/m and 0.04 × 10-6 ± 0.04 × 10-6 kg/s at 37 °C. These results indicate that the change in shell properties mediates the change in acoustic behavior of Definity® at physiological temperature.
Development of a methodology for field studies on the effects of aircraft noise on sleep
Authors: McGuire Sarah , Basner Mathias
Published: June 2017

An inexpensive yet sound study methodology is needed for field studies on the effects of aircraft noise on sleep. These studies are needed for developing exposure-response relationships that are representative of noise exposed communities around multiple airports and that can be used to inform policy. A methodology of monitoring sleep and identifying awakenings using ECG and actigraphy has been developed. An advantage of this approach is that ECG electrodes can be applied by investigated subjects themselves therefore reducing the need for staff in the field and the methodologic cost of the study. In addition, an automatic algorithm based on ECG and actigraphy data which identifies awakenings based on both body movements and changes in heart rate has been developed. The automatic scorings of the algorithm agree closely with awakenings identified using polysomnography which is the current gold standard for measuring sleep and related events. This ECG and actigraphy approach for monitoring sleep has been implemented in a pilot study conducted around 1 U.S. airport to evaluate its feasibility, in this study participants completed 3 nights of unattended sleep and noise measurements. Based on lessons learned, the study methodology has been further refined and implemented in a second pilot study.
Assessing vowel space area metrics in the context of dialect variation
Authors: Jacewicz Ewa , Fox Robert A.
Published: June 2017

There has been a growing interest in the development of a sensitive methodology to define a working vowel space area (VSA) as a metric in basic and clinical research applications. In this study, three approaches to the assessment of VSA were tested to evaluate their efficacy in characterizing cross-dialectal and cross-generational variation: The traditional vowel quadrilateral, the traditional convex hull, and a more liberal convex hull. In the two traditional approaches, VSA was computed as a planar convex polygon shaped by phonologically distinct vowel categories as its corners. The mean F1/F2 values at vowel midpoint were used to define the respective areas. The liberal convex hull utilized vowel dynamics and variable F1/F2 temporal locations to refine the outer boundaries and maximize the VSA. This approach used an unrestricted number of vowels and measurement locations to define the optimal VSA. All computations were based on a common speech material produced by 135 female speakers representing three American English dialects and four generations ranging from 8 to 91-year olds. The three metrics yielded inconsistent and contradictory estimates of VSA. Discussion will focus on the limited utility of polygon geometry in characterizing a working VSA in American English dialects.
So you wanna be a rock “n” roll star (there’s an app for that)
Authors: Ortallono Sam
Published: June 2017

With the increase of mobile recording technology more recordings are made in unconventional, acoustically uncontrolled environments. We designed an experiment to compare some of these spaces. At Lee College, we recorded the same song three times. The same musicians were recorded in three different spaces using different technology; in a large, controlled studio using ProTools, in a home studio setting using a laptop and in a living space using a mobile telephone application. Once the songs were mixed and mastered, college students were asked to rate the quality of the mixes.
Evaluation of a Loudspeaker-Based Virtual Acoustic Environment for Investigating sound-field auditory steady-state responses
Authors: Zapata-Rodriguez Valentina , Marbjerg Gerd , Brunskog Jonas , Jeong Cheol Ho , Laugesen Søren , Harte James M.
Published: June 2017

Measuring sound-field auditory steady-state responses (ASSR) is a promising new objective clinical procedure for hearing aid fitting validation, particularly for infants who cannot respond to behavioral tests. In practice, room acoustics of non-anechoic test rooms can heavily influence the auditory stimulus used for eliciting the ASSR. To systematically investigate the effect of the room acoustics conditions on sound-field ASSR, a loudspeaker-based auralization system was implemented using a mixed order Ambisonics approach. The present study investigates the performance of the auralization system in terms of objective room acoustic measurements and sound-field ASSR measurements, both in the actual room and in the simulated and auralized room. The evaluation is conducted for a small room with well-defined acoustic properties. The room is carefully modeled using the novel room acoustic simulation tool PARISM (Phased Acoustical Radiosity and Image Source Method) and validated through measurements. This study discusses the limitations of the system and the potential improvements needed for a more realistic sound-field ASSR simulation.
Standards for the characterization of high intensity nonlinear ultrasound fields and power generated by therapeutic systems
Authors: Szabo Thomas L.
Published: June 2017

The emerging field of high intensity therapeutic ultrasound (HITU) presents multiple challenges. Early attempts to characterize high pressure fields fried both hydrophones and force balances originally designed for diagnostic ultrasound. Working Group 6 of International Electrotechnical Commission (IEC) Technical Committee 87 initially sought out methods employing current validated measurement technology. Technical Specification 62256 focused on two field characterization approaches for water. The first was using conventional calibrated hydrophones in the linear range and a scaling up of field pressure values by the applied voltage ratio. The other method involved a finely sampled 2D scan near the transducer face as input data to linear projection algorithms to recreate the entire pressure field. This computed field could then be scaled up the previously described voltage ratio. An additional benefit of the second approach was that the same scan data could be used to predict pressure and thermal levels in simulated tissue media representing clinical scenarios. Technical standard 62255 described HITU power measurements with scaling and a novel buoyancy method. Current efforts are directed at the direct measurement of high pressure fields with new technologies and the data-based nonlinear simulation of fields and bioeffect end points in water and tissues.
Pacing and Self-regulation: Important Skills for Talent Development in Endurance Sports
Authors: Elferink-Gemser Marije T. , Hettinga Florentina J.
Published: June 2017

Pacing has been characterized as a multifaceted goal-directed process of decision making in which athletes need to decide how and when to invest their energy during the race, a process essential for optimal performance. Both physiological and psychological characteristics associated with adequate pacing and performance are known to develop with age. Consequently, the multifaceted skill of pacing might be under construction throughout adolescence, as well. Therefore, the authors propose that the complex skill of pacing is a potential important performance characteristic for talented youth athletes that needs to be developed throughout adolescence. To explore whether pacing is a marker for talent and how talented athletes develop this skill in middle-distance and endurance sports, they aim to bring together literature on pacing and literature on talent development and self-regulation of learning. Subsequently, by applying the cyclical process of self-regulation to pacing, they propose a practical model for the development of performance in endurance sports in youth athletes. Not only is self-regulation essential throughout the process of reaching the long-term goal of athletic excellence, but it also seems crucial for the development of pacing skills within a race and the development of a refined performance template based on previous experiences. Coaches and trainers are advised to incorporate pacing as a performance characteristic in their talent-development programs by stimulating their athletes to reflect, plan, monitor, and evaluate their races on a regular basis to build performance templates and, as such, improve their performance.