bluuebunny/crossref_metadata_2025 huggingface dataset:
Focus ultrasound for augmenting convection-enhanced delivery of nanoparticles in the brain
Authors: Mohammadabadi Ali , Hersh David S. , Anastasiadis Pavlos , Smith Philip , Woodworth Graeme F. , Kim Anthony J. , Frenkel Victor
Published: June 2017

We previously demonstrated how ultrasound can enhance the dispersion of locally administrated nanoparticles within the extracellular/perivascular spaces in the ex vivo brain by non-destructively enlarging these regions. The current study aimed to translate these results in vivo, where custom, non-adhering brain-penetrating nanoparticles (BPN: 60, 200, and 500 nm), were administered directly into the brains of Sprague Dawley rats by convection-enhanced delivery. Non-invasive, transcranial focused ultrasound (TCFUS) was carried out using an MRI-guided system (1.5 MHz, 10 ms pulses, 10% duty cycle, and 2.3 MPa). 15 individual exposures in a 3 × 5 matrix (spacing: 1.5 mm) in one hemisphere were given, where the size of the focal zone (-6 dB) was 1 × 1 X 8 mm. At 2hrs post-treatment brains were harvested and sectioned, with digital images captured and processed using a custom MATLAB script. This involved the “Otsu” thresholding method, based on gray level histograms and threshold determinations for maximizing the interclass variance. As expected, BPN distributions in the non-treated brains decreased with an increase in diameter. Pretreating with TCFUS was found to significantly increase the distribution of the 200 nm BPNs. These results have broad implications for therapeutic delivery for a variety of brain diseases and disorders.
Listening efficiency in real and simulated university classrooms
Authors: Prodi Nicola , Visentin Chiara
Published: June 2017

The present study examines how reverberation, background noise level and type, affect both speech reception performance and the perceived effort of students in a university classroom. The classroom has a volume of 198 m3 and a reverberation time in occupied conditions of 0.6 s, complying with the target value of the DIN 18041 standard. Diagnostic Rhyme Tests (DRT) in the Italian language were proposed to a group of 26 normal-hearing young adults: half of them native (Italian), the other half non-native (German) speakers. Data on speech intelligibility (SI) and response time (RT) were collected. The two quantities were combined in the joint metric of listening efficiency, effectively describing the interplay of perceptual and cognitive processes in speech reception performance. The experiment took firstly place in situ, where the distinct effects a speech-shaped stationary noise and a fluctuating (ICRA) noise with the same short-term STI were determined. Afterwards, acoustic simulations of the classroom setting were carried out, and the resulting binaural impulse responses used for laboratory experiments with headphones. Simulations and in-situ measurements were compared in terms of STI, SI and RT; then, listening tests under controlled conditions were accomplished with a selection of background noise levels and reverberation times.
Speakers comfort and voice use in different environments and babble-noise. What are the effects on effort and cognition?
Authors: Lyberg-Åhlander Viveka , von Lochow Heike , Whitling Susanna , Christensson Jonas , Nilsson Erling , Brunskog Jonas
Published: June 2017

Teachers often report voice problems related to the occupational environment, and voice problems are more prevalent in teaching than in other occupations. Relationships between objectively measurable acoustical parameters and voice use have been shown. Speakers have been shown to be able to predict the speaker-comfort of an environment. Teachers with voice problems use the room differently than their voice-healthy controls. The aim of this study was to investigate what vocal changes speakers do in different acoustical environments and noise conditions. Nine female speakers, voice patients, and voice-healthy were exposed to four controlled, acoustical “environments” mounted in the same room: 1. stripped; 2. wall- and ceiling mounted absorbents; 3-4 as 2 but with extra ceiling absorbents and in two positions. The speakers were recorded with voice-accumulator and simultaneous voice recordings and spoke freely for 3-5 min in three noise conditions in each setting: silence, classroom noise (60 dBA), and day-care noise (75 dBA). Questionnaires on effort needed were completed by speakers and listeners. There was a co-play between the rooms and the subjectively assessed vocal- and listening effort and also a correlation to cognitive aspects. Listener assessments and the data from the voice accumulator will be presented. This knowledge may contribute to the area of classroom acoustics and speakers’ comfort in general.
The frequency-dependent effects of low-intensity ultrasound exposure on human colon carcinoma cells
Authors: Verducci Chloe , Seay Hannah , Davis Janae , Longstreth Amy , Kwakwa Yaa , Herd Maria-Teresa
Published: June 2017

Previous studies have established a correlative relationship between the acoustic properties of normal and malignant epithelial cells in response to high-frequency ultrasound exposure, indicating ultrasound’s value as a tool in modern non-invasive cancer detection. More recently, ultrasound exposure has been extended into therapeutic fields, manipulated in frequency and power to stress and destroy specific cancer cells based on their determined acoustic properties. The present study seeks to determine the frequency-dependence of low intensity ultrasound exposure on varying cell types, beginning with colon carcinoma cells. The cells were exposed to a single element unfocused piezoelectric transducer at energies of less than 3 W/cm2 and frequencies of 0, 5, 10, 15, 20, and 25 MHz, and evaluated for cytotoxicity indicated by lack of cell adhesion before and after treatment. Comparison is also made to non-cancerous human colon epithelial cells. This project compares the frequency-dependent effects of low intensity ultrasound on cells of varying cancerous and non- cancerous lineages, especially highlighting the low-point threshold.
Determining the accuracy of sound field synthesis systems in reproducing subjective source locations
Authors: Catton Anna C. , Wang Lily M. , Bosen Adam K. , Vallier Timothy J. , Keefe Douglas H.
Published: June 2017

Sound field synthesis systems developed and applied to study human hearing perception differ in terms of the number and arrangement of loudspeakers in rooms of different sizes, and methods used to generate virtual sound environments. Research has evaluated how well such systems physically reproduce room acoustic conditions, but limited subjective data are available. This paper seeks to develop a method for determining the accuracy of the perceived localization of a virtual sound source generated using a multichannel sound synthesis system. A test method is applied to the sound field synthesis facility at Boys Town National Research Hospital, a room (5.8 m x 5.2 m x 2.7 m) with reverberation time of 0.16 s at 125 Hz and below 0.024 s at 250 Hz and above. Short bursts of broadband speech-shaped noise are presented at a number of virtual source locations under free-field and modeled reverberant-room conditions, and listeners are asked to point to the subjective source location. Subjective localization results are compared as functions of virtual sound location, and parameters of early reflections and reverberation in the modeled sound environment. Results are intended to guide future research on subjective room acoustics relevant to children's’ communication needs. [Work supported by NIH GM109023.]
Spatial distribution of sound field scattered from the rough seafloor interface
Authors: peng Linhui , Yu Gaokun , Lu JIanhui
Published: June 2017

The scattering coefficient of rough seafloor interface is calculated using first order perturbation theory. The interface roughness considered here is described by the isotropic power law spectrum for isotropic rough seafloor interface and anisotropic Gaussian spectrum for the rippled seafloor interface. The characteristic of spatial distribution is shown by the scattering coefficient of the scattered field with forward scattering and backward scattering, which depend on the frequency and the grazing angle of the incident wave, and the roughness of the interface. The dependence of spatial distribution of the scattered field on these parameters is analyzed by Bragg scattering of the sinusoidal interface.
Improvement of acoustic and thermal performances of façades on retrofit buildings
Authors: Semprini Giovanni , Di Bella Antonino , Secchi Simone , Barbaresi Luca , Granzotto Nicola , Fotopoulou Anastasia
Published: June 2017

Deep renovation of existing buildings represents an important strategy to go beyond the standard energy retrofit (as the increasing of thermal insulation of building envelope) and to provide more benefits to residents considering non-energetic aspects, like the improvement of architectural quality of building and of indoor life quality. In this context, façade's additional elements (balconies, solar greenhouses, etc.) can be effective solutions in order to increase thermal and acoustic performances as well as providing a more living space to the outside. This paper analyzes and compares different technical construction systems for façade improvement in order to define robust solutions correlated both to outdoor climate context (to increase energy performances towards nearly Zero Energy Buildings) and to outdoor noise for a better acoustic sound insulation. A case study is presented, and dynamic energy simulations, performed on a building made with materials and construction technology widespread in Italy in the '60s, show the energy impact of different solutions. The evaluation of acoustic façade insulation highlights the need to consider not only the properties of materials but also the effects of flanking transmission, sometimes correlated to thermal bridges, and façade shapes of which continuous balcony solutions give an important increase on acoustic performances.
Dynamic emergence of categorical perception of voice-onset time in human speech cortex
Authors: Fox Neal P. , Sjerps Matthias J. , Chang Edward F.
Published: June 2017

A fundamental challenge in speech perception involves the resolution of a many-to-one mapping from a highly variable, continuous sensory signal onto discrete, perceptually stable categories that bear functional relevance. Recent work has identified signatures of invariance in early neural responses to speech, but the physiological mechanisms that give rise to these categorical representations remain unclear. We employed intracranial recordings in human subjects listening to and categorizing speech stimuli to investigate the spatiotemporal cortical dynamics underlying categorical perception. Stimuli comprised a voice-onset time (VOT) continuum from /b/ (0 ms VOT) to /p/ (50 ms VOT). Results revealed spatially distinct neural populations that respond selectively to tokens from one category (either /b/ or /p/). Within these subpopulations, response amplitude is modulated by stimulus prototypicality for within-category stimuli (e.g., stronger response to 0 ms vs. 10 ms VOT in /b/-selective electrodes). Over the course of a trial, this initially graded encoding of VOT rapidly evolves to reflect properties of the ultimate (categorical) behavioral response function. These same dynamics emerged in a computational neural network model simulating neuronal populations as leaky integrators tuned to detect temporally distributed acoustic cues at precise lags. Our results provide direct evidence that categorical perception of VOT arises dynamically within discrete, phonetically tuned neural populations.
An experimental investigation into the insertion loss from subscale acoustic enclosures with geometric imperfections
Authors: Beale Christopher , Inalpolat Murat , Niezrecki Christopher , Willis David J.
Published: June 2017

Enclosures with different geometries constitute the internal sections of various engineering applications including cabins of passenger cars, fuselages of aircraft wings, and internal compartments of wind turbine blades. Acoustic insertion loss from and to these enclosures affect certain objective and subjective acoustic measures along with the ability to detect damage. This presentation describes a thoroughly executed test plan that identifies the effect of geometric imperfections, such as holes, edge splits, and cracks with different severity levels and locations, on the insertion loss from a subscale acoustic enclosure. A composite rectangular prism enclosure, located inside an anechoic chamber, was internally ensonified using a loudspeaker, and an externally located condenser microphone was used to measure the insertion loss under different conditions. One of the faces of the enclosure possessed various size and location imperfections simulating damage. Insertion loss deviations introduced through the prescribed damage cases were compared to a baseline case with no prescribed imperfections. The results obtained from the initial test campaign with healthy and damaged enclosure specimens were utilized to arrive at several conclusions on the detectability and feature extraction capabilities required for damage detection from subscale enclosures.
Passive and active acoustical studies of ocean surface waves
Authors: Ding Li
Published: June 2017

This paper reviews previous work with Professor David Farmer, on the use of acoustical techniques to observe and measure ocean surface waves. In passive acoustics, breaking surface waves in the open ocean were observed with a hydrophone array deployed close to the surface to track individual breaking events. The spatial and temporal statistics of braking events, such as velocity and breaking probability, were determined and compared with simultaneously measured directional wave spectra. The comparisons suggest that wave breaking occurs at multiple scales and that the mean scale of breaking is substantially smaller than the associated with the dominant wind wave component. In an active acoustical study, an incoherent bistatic sonar mounted on the seafloor was used to measure currents close to the ocean surface and within the crests of large, steep waves. Individual estimates of the currents at, and close to, the surface were made with sufficient temporal resolution to identify kinematics in the crests of large waves. Observations acquired in the North Sea are examined to evaluate both the potential merits and limitations of the measurement approach. The observations lead to some conclusions regarding wave kinematics during a storm in which the wind speed reached ∼17 m s−1.
An adaptive mirage
Authors: Rodriguez-Molares Alfonso , Rindal Ole Marius H. , Fatemi Ali , Austeng Andreas
Published: June 2017

We are in the middle of a Cambrian explosion. Software beamforming has redefined what can be done with the signal. As a consequence, our field has become flooded with adaptive beamforming (AB) algorithms, methods that by clever manipulation of channel data have exceeded our wildest expectations for the maximum achievable contrast and resolution. Or have they? If we define image quality in terms of the contrast ratio (CR) and the full-width half-maximum (FWHM), there is another way of getting unprecedented image quality. Dynamic range stretching, the kind of stretching one gets from squaring the beamformed signal amplitude, will also produce higher CR and smaller FWHM. If AB alters the output dynamic range, then the reported CR and FWHM are invalid. No tools are available yet for researchers and reviewers to check this. Here we address this problem. We propose a phantom to measure the dynamic range of AB. The phantom includes a speckle gradient band similar to those used in the calibration of monitors. The phantom allows us to confirm that AB algorithms can alter the dynamic range of the signal and produce incorrect CR and FWHM values. But it also makes it possible to compensate for that alteration and calibrate the algorithms. After calibration AB still results in higher image quality than delay-and-sum, but the metrics are more reasonable. A debate must be opened on the significance of AB algorithms. The metrics used to assess image quality must be revised. Otherwise, we risk to walk in circles, tricked by an illusion.
The ins and outs of capturing brain activities associated with auditory perception and cognition
Authors: Lee Adrian K. C. , Stecker G. Christopher
Published: June 2017

Magnetoencephalography, electroencephalography, and functional magnetic resonance imaging (MEG, EEG, and fMRI) have been used extensively to study human auditory perception and cognition. Due to the different temporal and spatial resolutions associated with each of these neuroimaging modality, each technique offers a different unique window into how our cortex participates in auditory tasks. In this talk, a number of classical paradigms will be presented and their relative strengths and shortcomings would be discussed. Other methodological advances and challenges particularly relevant to experiments in auditory perception and cognition will also be reviewed. [Work supported by NIH R01 DC013260 (AKCL) and R01DC011548 (GCS).]
Astounding sounds, amazing music—At the crossroads of audio control
Authors: Paradiso Joseph A.
Published: June 2017

The ways in which we produce, compose, discover, and consume music have changed profoundly in only the last decades as the conveyances of these capabilities have digitally converged. What does it mean to “play” a musical instrument and what will a musical performance become? In this presentation, I will explore these fringes via recent projects from my research team at the MIT Media Lab. This includes frameworks to enable composers to exploit sources of “big” data to realize their music (ranging from physics detectors at the Large Hadron Collider to a sensor-laden former cranberry bog turning into a wetland). In a related vein, I will introduce an interactive sonification framework we have devised to dynamically rotate complex data from visual to audio, with the goal of optimally engaging eyes and ears. At the other extreme, I will describe a set of new physical instruments for musical control, such as stretchable fabric keyboards, instruments designed to be breakable during performance, and collaborative instruments that leverage social media and the Internet of Things. Finally, I will give my perspective on the recent resurgence of modular synthesizers, grounded in having built and designed perhaps the world’s largest homemade modular system between 30 and 40 years ago.
Active control of Chinese gongs
Authors: Jossic Marguerite , Denis Vivien , Thomas Olivier , Mamou-Mani Adrien , Chomette Baptiste , Roze David
Published: June 2017

Active control provides one of the most promising ways of modifying instruments' sound. However, among the various control techniques covered by this discipline, most of the experimental applications have so far been limited to instruments keeping a linear behavior in normal playing conditions. This study explores the possibility of applying active control to Chinese gongs. These instruments exhibit geometric nonlinearities in their dynamical behavior such as a very characteristic pitch glide of the fundamental mode. The implementation of a nonlinear control of this pitch glide is introduced following a two-steps process. First, a reduced nonlinear model of the instrument dynamics is determined from the von Karman and normal form theories. This formulation allows for describing the nonlinear dynamics of the fundamental mode by one single nonlinear mode governed by a Duffing equation. The experimental identification of the Duffing model parameters is performed by measuring the backbone curve of the fundamental mode in forced vibrations. Second, the methodology for the nonlinear control is developed. In particular, the determination of the control law and the overall stability of the control system are discussed. Control simulations results as well as perspectives for experimental applications are finally exposed.
Beyond the Noise: Open Source Soundscapes. A mixed methodology to analyze and plan small, quiet areas on the local scale, applying the soundscape approach, the citizen science paradigm, and open source technology
Authors: Radicchi Antonella
Published: June 2017

Today, cities have become increasingly noisier. In Europe, over 125 million people are affected by noise pollution from traffic every year, and apparently, quietness is becoming a luxury available only for the elites. There is a growing interest in protecting and planning quiet areas, which has been recognized as a valid tool to reduce noise pollution. However, developing a common methodology to define and plan quiet areas in cities is still challenging. The “Beyond the Noise: Open Source Soundscapes” project aims to fill this gap of knowledge by applying the soundscape approach, the citizen science paradigm and open source technology, with the ultimate goal of making quietness as a commons. Accordingly, a new mixed methodology to analyze and plan small, quiet areas on the local scale has been tested through the development of a pilot study in a Berlin neighborhood affected by environmental injustice and noise pollution. In this pilot study, a number of citizens have been involved in crowdsourcing data related to “everyday quiet areas” by using novel mobile technologies. This contribution illustrates the project’s theoretical background, the methods applied, the first findings of the study and its potential impact.
Resonance of damping
Authors: Bobrovnitskii Yuri
Published: June 2017

Considered is a linear forced vibrating structure (primary structure) to which another linear passive structure (absorber) is attached at a number of points. It is shown analytically that the vibration power flow from the primary structure to the absorber reaches its absolute maximum if two conditions are met simultaneously. The first condition is well known: there must be a frequency resonance when the forcing frequency coincides with one of the eigen frequencies of the primary structure/absorber system. The second condition is also of the resonant type: at the frequency resonance vibration mode, the amount of damping in the absorber must be equal to the amount of damping in the primary structure. This can be called the resonance of damping. The vibration or sound absorber that satisfies both resonance conditions can be called the best or the perfect absorber. The theoretical result obtained has been verified in a laboratory experiment with a simple primary structure and a dynamic vibration absorber as well as in an impedance tube on a resonant sound absorber. Relation to results known from the literature and possible applications using metamaterials are discussed.
Ira Dyer at MIT—Professor, Department Head, and Arctic pioneer
Authors: Baggeroer Arthur B. , Mikhalvesky Peter
Published: June 2017

Ira arrived at MIT in 1970 from BBN to take a professorship offered by Alfred Kyle, Head of the Department of Naval Architecture. He had said yes; however, Kyle surprised him and asked him to also head the department, renamed Ocean Engineering. With some trepidation he accepted. He started new research programs in ocean acoustics, ambient noise, reverberation and propagation while making seminal contributions. He became the director of the MIT Sea Grant Program and soon MIT was one of the first Sea Grant colleges. In 1977 Ira had the idea to research basin-scale reverberation. He thought the Mediterranean would be the ideal enclosed basin including opportunities for post-experiment R&R! He approached the Office of Naval Research, they enthusiastically agreed, and sent him to the Arctic! That detour north turned into a super highway of decades of Arctic acoustics research from a controversial seamount discovery in his first reverberation experiment, detailed morphology of ice cracking noise, propagation and ice scattering to global climate change. Ira will have lasting and enduring impact in acoustics through his contributions and through his many students and colleagues that had the great privilege and joy to learn from, know, and work with Ira.
Nonlinearity based wave redirection for acoustic metamaterials
Authors: Telly Saliou , Balachandran Balakumar
Published: June 2017

Advances in metamaterials have revealed novel opportunities for controlling wave propagation paths for various applications not realizable with conventional materials. Some prominent examples are schemes for electromagnetic and acoustic cloaking and focusing devices. In the classical approach to the formulations of these devices, one exploits a change of physical coordinates to achieve a desired wave behavior within a finite space. Such a change can be interpreted as a transformation of material properties when the field equations of interest are invariant to coordinate transformations. With regard to acoustics, this approach is constrained to fluid-like metamaterials amenable to the propagation of longitudinal waves only. Complications arise with solid materials because of their inherent ability to sustain both longitudinal and transverse waves, which refract differently in linear isotropic materials because of dissimilar propagation speeds. In this work, the authors explore wave redirection mechanisms that may take advantage of nonlinear wave propagation phenomena in a solid metamaterial. Starting from the classical nonlinear Murnaghan model, a hyper-elastic material is formulated to realize coupling between shear and compressional modes that could lead to a more suitable refractive behavior for acoustic wave redirection in a solid metamaterial. The formulated model is studied using analytical and numerical tools.
Modal beamforming for circular acoustic vector sensor arrays
Authors: Gur Berke M.
Published: June 2017

Vector sensors are directional receivers that measure the vectorial particle velocity associated with an acoustic wave rather than the scalar pressure. Therefore, arrays of vector sensors possess some desirable directional properties compared to conventional arrays of pressure sensors. In this paper, a modal beamformer for circular arrays of 1-D acoustic vectors sensors are presented. Arrays of both radially and circumferentially oriented vector sensors are considered. It is shown that the highly directional modes of the acoustic velocity field can be extracted from the sensor measurements using the spatial Fourier transform. These modes are weighted and combined to form narrow steerable beams. The highest order of mode that can be extracted is limited by the number of vector sensors utilized in the array. Theoretical analysis and numerical simulations indicate that the proposed modal beamformer attains the same directivity performance as that of circular pressure sensor array beamformers but outperforms them in terms of white noise gain. In addition, it uses half the number of sensors to achieve the same directivity performance of a circular vector sensor array modal beamformer reported previously in the literature. The proposed method is suitable for in-air and underwater low frequencies array processing applications.
Profiles in sonar: Reflections on F. V. Hunt
Authors: Eller Anthony I. , Pyle Robert W.
Published: June 2017

Frederick Vinton Hunt was one of the towering figures who helped to shepherd the development of SONAR, an acronym for Sound Navigation and Ranging, from its infancy to near maturity. We two authors of this paper had the great advantage and pleasure of having Ted Hunt as a mentor during the latter part of his career and the early stages of our own. In this presentation we outline briefly the history of SONARs development as a means of placing Hunt’s contributions in context. This would include largely his time at Harvard during the R&D phase of SONAR’s growth, followed by his role during the 25 years following WWII as educator. Ideas are discussed related to what features of his mentorship are responsible for creating the next generation of leaders in science and technology.
Rapid impedance tube determination of fabric transparency
Authors: D'Antonio Peter , Cox Trevor J.
Published: June 2017

Acousticians are continually being asked to verify fabric transparency for applications with absorptive and diffusive surfaces, as well as in sound reinforcement. Standard reverberation chamber methods can be used, but require large fabric and fiberglass samples. A quick and simple impedance tube method has been developed requiring only a 160 mm x 160 mm sample. Two measurements are made. One with an anechoic wedge termination and another with a rigid termination in which the fabric is applied to a 50 mm 6pcf fiberglass substrate. Four microphones are placed at a quarter and three quarters of the square tube’s width and height and the signal is summed. This unique microphone placement minimizes the 1st, 2nd, and 3rd harmonics resulting in a fourfold increase in the upper frequency limit. Impulse response measurements are made at three distances from the sample to calculate the reflection factor, impedance and normal incidence absorption coefficient from 63 Hz to 4000 Hz in one measurement. The small fabric sample is large enough to minimize non-homogeneous effects. A study of fabrics with a wide range of transparencies reveals how both acoustically transparent and backed fabrics can be used as sonic equalizers depending on the application.
How canaries listen to their song
Authors: Fishbein Adam , Lawson Shelby , Ball Gregory F. , Dooling Robert
Published: June 2017

Canaries have become important models for the study of vocal learning. The male produces long song bouts up to a minute long consisting of various syllables, each repeated in flexibly sequenced phrases. Little is known about how the birds listen to song though behavioral observations clearly show that female canaries are more sexually responsive to a special song element—so called “sexy” syllables—which are distinguished by a high syllable repetition rate, wide-bandwidth, and multiple notes. Here, operant conditioning and psychophysical techniques were used to determine the discriminability of variation in syllable and phrase morphology. Results show that canaries can discriminate the subtle differences among syllables and phrases using spectral, envelope, and temporal fine structure cues but they are no better than budgerigars used as controls. There was also evidence that perception of sexy syllables is distinctive for canaries. On the whole, while canaries can hear the fine details of the acoustic structure of their song, the evidence suggests that they listen at a more synthetic rather than analytic level. These results give clues to how the canary perceptual system may be shaped to process male song and make judgments about mate quality.
Observations of non-zero asymptotes for high annoyance at low sound exposure levels
Authors: Horonjeff Richard
Published: June 2017

Social survey data relating the prevalence of a high annoyance to transportation noise typically indicate a decrease in annoyance rate with decreasing exposure. At very low exposure levels, the expectation is that the percentage of highly annoyed respondents will asymptotically approach a value of zero. In many studies this has in fact been the case. In some studies, however, the lower asymptote does not appear to be zero, however, but rather some small, non-zero value. Such non-zero asymptotic values are sometimes nearly constant over an exposure range of as much as 10 decibels. In other words, the observed prevalence of noise-induced annoyance appears to be independent of sound level over an extended range, before beginning to depend on noise dose at higher levels. Several examples of this phenomenon are presented and discussed.
Removing distortions from ground sonic boom measurements for certification of over land flight
Authors: Morgenstern John M.
Published: June 2017

Ground measurements of sonic booms contain distortions acquired during their propagation through the atmosphere that greatly changes their loudness. Quiet shaped boom vehicles are being proposed for acceptable over land flight. Because of distortion loudness variations, many ground measurements would be needed to develop accurate statistics of loudness. And highly turbulent atmospheres increase loudness variations and affect average loudness, so a limited range of atmospheric conditions would be required for a certification procedure of acceptable loudness. More flights and limited conditions would substantially increase vehicle certification cost. A measurement de-turbulencing technique is shown to greatly reduce atmospheric distortions. It improves loudness accuracy to (hope to quantify) from a single pass over a line of at least 25 microphones. The method combines a de-turbulencing technique developed by Plotkin, with a spatial averaging technique used in wind tunnel measurements of sonic boom, and with additional analytical methods being developed. The de-turbulencing and spatial averaging has been applied to F-5SSBD measurements, resulting in a consistent loudness 2 PLdB quieter than analytical predictions due to greater rounding of the averaged turbulence distortions.
Acoustics in disordered granular materials: From the particle scale to force networks
Authors: Daniels Karen
Published: June 2017

Granular materials are inherently heterogeneous, and continuum models of properties such as the shear modulus and sound speed often fail to quantitatively capture their dynamics. One likely reason, particularly in soft materials, is the transmission of forces via a chain-like network of strong forces. I will present several methods of characterizing sound transmission within such materials, combining both high-speed imaging and particle-scale piezoelectric measurements. In experiments on compressed granular materials, we observe that the amplitude of propagating sound is on average largest within particles experiencing the largest forces, due to the increased particle contact area. In addition, we find that the particle-scale density of vibrational modes exhibits systematic changes associated with the amount of compression, shear strain, or disorder in the system. We have found that a helpful theoretical framework is to consider a network representation in which the nodes (particles) are connected by weighted edges obtained from contact forces (visualized using photoelastic materials). Such network representations provide a mathematical framework which allows for the comparison of features and dynamics at different spatial scales. Collectively, these measurements highlight the importance of this force chain network in controlling the bulk properties of the material.
Transformable origami-inspired acoustic waveguides
Authors: Bertoldi Katia , Tournat Vincent , Babaee Sahab , Overvelde Johannes
Published: June 2017

Using foldable origami-like structures, we design reconfigurable and switchable acoustic waveguides composed of interconnected periodic arrays of hollow tubes to manipulate and guide sound. We demonstrate both numerically and experimentally that upon application of external deformation, the structure is folded and transformed to one-, two-, and three-dimensional waveguide in which sound waves travel through the tubes. The proposed design expands the ability of existing acoustic waveguides by enabling tunability induced by reversible deformation and folding shape transformation over a wide range of frequencies, opening avenues for the design of novel tunable waveguides and adaptive sound filters.
Photoacoustic effect of ethene: Sound generation due to plant hormone gasses
Authors: Ide David W. , Park Han Jung
Published: June 2017

Ethene (C2H4), which is produced in plants as they mature, was used to study its photoacoustic properties using photoacoustic spectroscopy. Detection of trace amounts, with N2 gas, of C2H4 gas was also applied. The gas was tested in various conditions- temperature, concentration of the gas, gas cell length, and power of the laser to determine their effect on the photoacoustic signal, the ideal conditions to detect trace gas amounts, and concentration of C2H4 produced by an avocado and banana. A detection limit of 10 ppm was determined for pure C2H4. A detection of 5% and 13% (by volume) concentration of C2H4 produced for a ripening avocado and banana, respectively, in closed space.
A transfer function approach for measuring the characteristic impedance and propagation constant of porous materials
Authors: Huang Zhehao , Wang Xiaolin
Published: June 2017

A four-microphone one-load transfer function (4M1L) method using an impedance tube is proposed for estimating the characteristic impedance and propagation constant of porous materials, referring to the standard two- and four-microphone methods (ISO 10534-2, ASTM E2611-09). The material in this single measurement method does not have to be geometrically symmetrical and homogeneous. Even the material is geometrically asymmetrical and inhomogeneous, like a multi-layered system, an equivalent-impedance model can be assumed. Moreover, this method can also be used in the presence of a mean flow. First, in this presentation, the measuring theories of conventional two-microphone transfer function (2M2L), three- and four-microphone transfer matrix (3M2L, 4M2L) methods are discussed and compared with this 4M1L method,. Second, a direct measurement for various multi-layered materials mounted with a hard termination is used to verify this measurement method and material characterization by the equivalent-impedance model. Last, measurement and calculation results are presented and compared with the conventional 4M2L method. The 4M1L method can be of help in acoustic properties measurement of sound absorbing materials.
Directional information extracted from time reversal scanning to image stress corrosion crack orientation
Authors: Anderson Brian E. , Ulrich Timothy J. , Le Bas Pierre-yves , Remillieux Marcel , Reichman Brent O.
Published: June 2017

The time reversed elastic nonlinearity diagnostic (TREND) is a nondestructive inspection technique based on the principle of time reversal and used to scan the surface of a sample to identify and characterize cracks and other defects. TREND utilizes a series of individual time reversal experiments conducted on a grid of points in a region of interest to map out the spatial extent of surficial expressions of cracks and subsurface features that are less than a wavelength below the surface. The focal signatures from each of these experiments can be used to determine not only the location but also the orientation of the crack. We will discuss how this technique can be applied to a stainless steel sample with stress corrosion cracking (SCC) using stationary piezoelectric transducers broadcasting ultrasonic waves and a scanning laser vibrometer setup used to detect the three dimensional vibration of the sample surface. The orientation of the crack is critical to estimate how soon a crack might penetrate through the wall thickness of a structure. [This work was funded by the U.S. Dept. of Energy, Fuel Cycle R&D, Used Fuel Disposition (Storage) campaign and through a Nuclear Energy University Program Integrated Research Project (IRP-15-9318).]
Acoustic regulations and classification of new and retrofitted buildings in Russia
Authors: Tsukernikov Ilya E. , Shubin Igor L. , Nevenchannaya Tatiana O.
Published: June 2017

The paper presents requirements acting in Russian Federation for acoustic regulation of an internal climate in new and retrofitted buildings. The positions of two federal laws are considered which regulate the requirements to acoustic parameters of dwellings and harmful influences. The list of the basic sanitary regulations setting hygienic requirements to acoustic factors is given. Substantive provisions of the code of rules are resulted, which establish obligatory requirements in norms of admissible noise in premises of buildings of different function, an order of carrying out of acoustic calculations according to a noise mode in these premises of buildings, an order of a choice and application of various methods and means for decrease in calculated or actual noise levels to meet the sanitary regulations. Requirements to the declaration of airborne sound insulation characteristics of building sound-proof products, methods for the establishment and verification of the declared values, and also the data which should be included in the technical and operational documentation at the statement of characteristics of airborne sound insulation according to the national standard GOST Р 56235-2014 are stated.
From A-mode to virtual beam: 50 years of diagnostic ultrasound
Authors: Kremkau Frederick W.
Published: June 2017

In the 50 years from 1967 (the year that, as a student, I met Edwin Carstensen) to 2017, diagnostic ultrasound has progressed from A mode to M mode to B&W static 2D to gray-scale static 2D to real-time 2D to static 3D to real-time 3D (“4D”). Along the way, other modes and features appeared including analog-to-digital, color-, power- and spectral-Doppler, coded excitation, harmonic imaging, panoramic imaging, spatial compounding, contrast agents, elastography and virtual beam forming. Contrast agents have been in wide use globally for years, although limited in the U.S. by the FDA to cardiac application until recently. Contrast agents operate on the ability of gas bubbles to strongly reflect ultrasound. In a 1968 study conducted by Professors Carstensen and Gramiak and me, it was shown that the contrast effect was due to bubbles in the radiologic contrast agent. As an electrical engineering graduate student at the time, I could not know that this was the launching of a 50-year medical academic career in sonography. Prof. Carstensen was instrumental in guiding me into this exciting and rewarding career. This presentation concludes with a comparison of contemporary physical and virtual beam formation and its impact on image quality.
Subjective perception of wind turbine noise
Authors: Cooper Steven E.
Published: June 2017

Subjective testing of wind turbine noise to examine amplitude modulation and subjective loudness has tended to use large baffle speaker systems to produce the infrasound/low frequency noise and one high frequency speaker—all as a mono source. Comparison of mono and stereo recordings of audible wind turbine noise played back in a test chamber and a smaller hemi-anechoic space provides a distinct and different perception of amplitude modulation of turbines. A similar exercise compares the use of high quality full spectrum headphones with the two different sound fields applied to just the ears.
Mechanical rainbow trapping and Bloch oscillations in chirped metallic beams
Authors: Sanchez-Dehesa Jose , Arreola-Lucas Arturo , Baez Gabriela , Cervera Francisco , Climente Alfonso , Mendez-Sanchez Rafael
Published: June 2017

The mechanical rainbow trapping effect and the mechanical Bloch oscillations for torsional waves propagating in chirped mechanical structures are here experimentally demonstrated. After extensive simulations, three quasi-one-dimensional chirped structures were designed, constructed and experimentally characterized by Doppler spectroscopy. When the chirp intensity vanishes, a perfect periodic system, with bands and gaps, is obtained. The mechanical rainbow trapping effect is experimentally characterized for small values of the chirp intensity. The wave packet traveling along the structure is progressively slowing down and is reflected back at a certain depth, which depends on its central frequency. For larger values of the chirping parameter the rainbow trapping yields the penetration length where the mechanical Bloch oscillations emerge. Numerical simulations based on the transfer matrix method show an excellent agreement with experimental data.
A new expression for the second-order acoustical nonlinearity parameter B/A for a suspension of free or encapsulated bubbles
Authors: Xia Lang , Sarkar Kausik
Published: June 2017

The presence of bubbles in the liquid introduces dispersion, increased attenuation and nonlinearities in the medium (bubbly liquid). The second-order acoustical parameter B/A describes the nonlinearity of the bubbly liquid. The nonlinear parameter B/A is an important property for characterizing different media and materials, and also important for ultrasound imaging. It can be derived from the equation of state of a fluid using the Taylor expansion to the second order. B/A has been studied extensively in industrial, chemical and biological fluids since Beyer proposed this thermodynamic technique. However, certain important aspect for this criterion remains unexplored specifically for bubbly liquid. Here, we develop a new formula based on the thermodynamic method which correlates both attenuation and phase velocity of ultrasound waves in liquids containing free or encapsulated microbubbles. These quantities can be measured directly using a broadband technique. The formula offered here is relatively simple and can be used to directly measure B/A from experiments; the new formula avoids using second harmonics that requires higher excitation pressures, as well as the direct thermodynamic method that gives rise to inaccuracy.
Pitch recognition with sparse-coding recurrent neural networks
Authors: Barzelay Oded , Barak Omri , Furst Miriam
Published: June 2017

Pitch is a percept of the mind that correlates to, but not solely with, acoustical periodicities. Simply stated, it relates different acoustic signals that share the same repetition rate into one percept. In contrast, various stimuli entering the acoustical periphery are expressed differently in the auditory nerves population response. Thus, there is a difference between the input activity and the percept of the brain. Broadly, two leading opponent approaches exist, temporal models and spatial models, but these models can explain partly disjoint features of the pitch. We propose a novel approach to bridge the gap between these two extremities. It is based on optimality constraints that assume parsimonious representation of the sensory auditory input. A recurrent neural network is trained to extract spatiotemporal patterns—pitch cues—from the auditory nerves population activities. These pitch cues are then linearly related to the stimulus' pitch. The model can explain different stimuli from psychoacoustic experiments, such as resolved and unresolved pitch, Transposed Tones, iterated rippled noise, nonlinear amplitude responses of the stimuli, harmonic shift, and musical notes. The uniqueness of this model is its ability to explain various psychoacoustic phenomena within one mathematical framework that is suggested to be shared with other modalities.
Pitch height as part of speech plans: Evidence from response to auditory startle
Authors: Chiu Chenhao
Published: June 2017

In Mandarin, pitch contour denotes phonemic contrast while pitch height does not serve as a phonemic parameter. When triggered by a startling auditory stimulus (SAS, >120dB), prepared Mandarin CV syllable [ba] is elicited rapidly while its pitch contour remains unperturbed, suggesting that phonemic details are included in the speech plan and susceptible for rapid release under feedforward control [Chiu and Gick 2014, JASA-EL, 322-328]. Pitch height, however, is elevated in SAS-induced responses. It is not clear whether or not pitch height can be independently pre-specified in speech plans. The current study uses the startle paradigm to tackle this question by comparing general Mandarin speakers and Mandarin speakers with pitch training. Preliminary results show that specific pitch height can be prepared and is preserved in SAS-induced responses. More unperturbed pitch height is observed in pitch-trained speakers’ responses than in general Mandarin speakers’ responses. While slight and limited elevation may occur at the beginning of SAS-induced responses, the preservation of the absolute pitch height appears to interact with intended response durations. The results suggest that absolute pitch height, even when not acting as a phonemic parameter, can be pre-specified in speech plans and released by a SAS both rapidly and accurately.