bluuebunny/crossref_metadata_2025 huggingface dataset:
Bioeffects of microsecond pulses of ultrasound—Launching a new era in diagnostic ultrasound safety
Authors: Fowlkes Jeffrey B.
Published: June 2017

Over 30 years ago, a provocative letter to the editor [Carstensen, E. L. & Flynn, H. G. The potential for transient cavitation with microsecond pulses of ultrasound. Ultrasound Med. Biol. 8, L720-L724, doi:10.1016/0301-5629(82)90134-X (1982)] launched a new era in bioeffects and safety research for medical ultrasound. This letter questioned the presumed safety of diagnostic ultrasound and the result has been on ongoing intellectual effort that has influenced the research and regulatory environment throughout the world. Based on both an experimental observation and a theoretical framework of bubble dynamics, the fundamental potential for cavitation from short pulses of ultrasound, as used in diagnostic ultrasound, and its associated bioeffects in the presence of appropriate nuclei was brought into clear focus and created a driving force and call to action by the academic community. Many young researchers in this field started their careers investigating this early proposal that would shape decades of ultrasound investigation. This presentation will review the origins of work and some of the influences it has had on bioeffects research and the safety and regulatory aspects found today in diagnostic ultrasound.
A MEMS microphone with repulsive sensing
Authors: Ozdogan Mehmet , Towfighian Shahrzad , Miles Ronald
Published: June 2017

The most common types of MEMS microphones are based on the capacitive sensing principle because of their ease of integration and their ability to detect low pressure fluctuations. One bottleneck in the design of conventional electrostatic MEMS microphones is that the sensitivity is impaired by the pull-in effect in parallel-plate capacitors. The electrical sensitivity of the microphone is a linear function of the bias voltage applied on the microphone. To increase the sensitivity and signal to noise ratio, the bias voltage should be increased, but the bias voltage is severely limited to the pull-in voltage, where the diaphragm will collapse into the backplate. To address the sensitivity issue in MEMS microphones, we devised a new type of capacitive sensor that creates a repulsive force rather than an attractive force, thereby completely avoiding the pull-in effect. The pull-in voltage has constrained the performance of capacitive microphones since their invention by Edward C. Wente in 1916. The ability to avoid pull-in will enable microphone designs with more compliant diaphragms and will result in significantly higher sensitivity, higher resolution, less noise and flatter frequency response. We will demonstrate our simulation results on the dynamic and acoustic responses of the MEMS microphone and present our experimental results for validation.
Comparisons of the performance of commercially-available hearing aid microphones to that of the Binghamton Ormia-inspired gradient microphone
Authors: Miles Ronald
Published: June 2017

Comparisons are presented of the performance of a MEMS differential microphone inspired by the ears of the fly Ormia ochracea with that of commercially available high-performance microphones. The results presented here compare the frequency response, 1/3rd octave band noise floor, and directionality of the Ormia microphone with what can be achieved with state-of-the-art commercially available miniature microphones. The Ormia microphone is found to provide significantly better performance than the existing microphones in each response category.
New Ormia-inspired directional microelectromechanical systems microphone operating in a low-frequency band
Authors: Zhang Yansheng , Bauer Ralf , Windmill James F. , Uttamchandani Deepak , Jackson Joseph
Published: June 2017

Directional MEMS microphones inspired by the parasitoid fly Ormia ochracea have been studied since the discovery that the micro-scale tympana structure of this female fly can amplify and locate narrow band mating calls from its host. This presentation will concentrate on the first piezoelectric Ormia-inspired MEMS microphone that operates in a low range of frequency bands overlapping with human vocal frequencies, and as such is suitable for hearing aid applications. Including two plates performing as Ormia’s two tympana, the entire region in motion in our microphone is about 3.2 mm × 1.42 mm × 10 μm. Compared to other piezoelectric Ormia-inspired designs, our design transfers the working frequency band from over 10 kHz to below 3 kHz due to its asymmetric structure and an S-type rotational cantilever. Furthermore, it provides a unidirectional response around two resonance frequencies below 3 kHz. The open-circuit acoustic response of the device is approximately 3.9 mV/Pa at 464 Hz which is close to human vocal frequencies, with a maximum value of 9.9 mV/Pa at 2275 Hz, which is near the frequency region where the human auditory system is most sensitive. The new microphone, coupled with a custom-built preamplifier, has a noise floor of 10 μV/√Hz at 1 kHz.
Thermodynamic investigation on the PMN-PT stoichiometry change during thermocycling
Authors: Sabarou Hooman , Huang Dehua , Zhong Yu
Published: June 2017

A new thermodynamic investigation on the (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT, x = 0.25) single crystal has been carried out to understand the structural evolution during the thermocycling processes. The samples have been examined by three thermocycle regimes: 250-300°C, 300-400°C, and 400-600°C, under air and argon atmospheres. The XRD refinement after thermocycling experiments identified the existence of two different rhombohedral phases (Rc and R3m), in addition to the retained cubic phase (Pmm) at room temperature. It also predicted the existence of the retained rhombohedral phase at a high temperature. The results for the first time show that PMN-PT has a unique weight-change phenomenon during the thermocycling processes, i.e., weight loss is observed in the first stage while weight gain is observed in the last stage. It is believed that this novel phenomenon is affected by the structural evolution and the formation of the retained rhombohedral and cubic phases, respectively. It is believed that the stoichiometry changes observed are closely related to the electric fatigue phenomenon of piezo-electric materials.
Modeling of continuous acoustic field with sparse transducer arrays
Authors: Miller Lane P. , Thompson Stephen C. , Dittberner Andrew
Published: June 2017

The overarching objective of this research is to explore the effectiveness of reproducing an acoustic field with a sparse array of transducers. This paper presents a comparison of the beam pattern formed by an arbitrarily acoustically excited rectangular aperture with that of a sparse array of transducers with approximately the same dimensions of the rectangular aperture. The accuracy of sparse arrays containing different numbers of transducer elements in different physical arrangements is investigated. The beam-forming accuracy for different frequencies, given as ratios of wavelength to aperture size, is also investigated. Conclusions determine the precision with which continuous sound-radiating apertures may be modeled by discrete representations, as well as the expected minimum number (and arrangement) of sources required for optimal sound field reproduction.
A correction method for the two-microphone transfer function technique in the free field using numerical modeling
Authors: Hall Hubert S. , Vignola Joseph F. , Judge John , Turo Diego
Published: June 2017

The two-microphone transfer function technique of measuring absorption coefficient in a free field has remained unchanged since its development in the 1980s. The free field technique has remained scarcely used due to usage restrictions caused by sound field contributions from diffraction of the test sample edge. Currently, the technique is only valid for instances where field contributions from edge diffraction is sufficiently minimized. This research uses acoustic numerical modeling to study the effects of error sources on the technique. Numerical models have been developed and used to quantify the effects of “image source deviation” and edge diffraction on the implementation of the free field technique. Each error source is quantified independently. Updated guidance on the usage restrictions of the free field technique is provided. Additionally, an improvement to the free field technique using a correction method is proposed. An experimental validation of the correction method was performed. The correction method showed improvement to the current two-microphone free field technique for higher frequencies (> 800 Hz) for samples 9” and larger as long as the nearest microphone location is no more than 16.7% of the sample width.
Extension of the phase and amplitude gradient estimation method for acoustic intensity to narrowband sources
Authors: Succo Kelli , Sommerfeldt Scott D. , Gee Kent L. , Neilsen Tracianne B.
Published: June 2017

The phase and amplitude gradient estimation (PAGE) method [D. C.Thomas et al., J. Acoust. Soc. Am. 137, 3366-3376 (2015)] has proven successful in improving the accuracy of measured energy quantities over the traditional p-p method in several applications. For example, the PAGE method has successfully increased the bandwidth over which magnitude and phase calculations are accurate for broadband sources with smoothly varying phase. This is partially accomplished by unwrapping the phase relationship in order to get valid phase information above the spatial Nyquist frequency. However, narrowband sources may not have sufficient coherent bandwidth information for a phase unwrapping algorithm to unwrap properly. To test the limits of the PAGE method on narrowband sources, sine waves, sawtooth waves, and bandlimited white noise have been used in various scenarios. In one-dimensional tests of these signals, the PAGE method provides correct magnitude and direction for frequencies up to the spatial Nyquist frequency, which represents an extended bandwidth over the p-p method. Additional specific results for the different input signals are presented. Also presented are the results of using low-level broadband noise propagating in the same general direction as the source to provide sufficient information for accurate phase unwrapping. [Work supported by NSF.]
Normal incidence sound absorption of parallel absorber at high sound pressure
Authors: Chiang Yan Kei , Choy Yatsze
Published: June 2017

A finite element model is developed to simulate the acoustic response of the parallel absorber array at high sound intensity. The device consists of an MPP and a rectangular backing cavity which is divided into two sub-cavities with different cavity depths. At high acoustic excitation, a nonlinear impedance model instead of the traditional linear model is adopted such that the effects of jets and vortex rings formed at the exit of orifices on the acoustic properties are taken into account. The normal incident pressure is considered as a main variable of the nonlinear acoustic impedance model. The performance of the MPP absorber array with different designed geometric parameters are studied. Based on the parallel absorption mechanism, the preliminary results show that the MPP absorber array provides good absorption performance with a wider frequency range by comparing with the single MPP absorber. Also, compared with the results obtained in linear regime, a better absorption performance is achieved by the MPP absorber array at high sound intensity due to the higher acoustic resistance. The acoustic behaviors of the MPP absorber array are also studied experimentally under normal incidence. The predicted and measured results show good agreement.
Propagation of sound through a series of contraction micro-tubes
Authors: Jiang Changyong , Huang Lixi
Published: June 2017

Ordinary fibrous material is mainly quantified by its density and the acoustic resistance is tightly coupled with other parameters, a feature which is not always desirable for every sound absorption task. This study investigates the acoustic property of a structure consisting of unit cells made by simple contraction tubes. Wave element method is used to simulate the property of a unit cell, and the equivalent fluid model is employed to calculate the performance of an absorber of finite thickness. The acoustic mass and resistance are controlled by the contraction ratio and the diameter of small tubes, respectively. In terms of the spectra of sound absorption, it is shown that the contraction ratio mainly controls the peak frequency of the absorption curve while the tube diameter influences the bandwidth of absorption. The performance of the finite absorber is compared with the usual layer of porous material, and the structure parameters are conveniently optimized for specified sound absorption tasks. A multiple layer of structures, each with a different set of parameters, may be used to achieve a very broadband performance, and the simplicity of the unit cell design facilitates the multi-layer optimization process.
A parametric study of flexible micro-perforated panels with a patch-impedance numerical model
Authors: Temiz Muttalip A. , Tournadre Jonathan , Lopez Arteaga Ines , Hirschberg Avraham
Published: June 2017

The absorption characteristics of a single flexible micro-perforated panel with a back cavity are compared for different combinations of physical parameters. Provided that the panel is made of a rigid plate, the acoustic properties of a micro-perforated panel are determined by the plate thickness, the distribution and diameter of the perforations, the porosity, the edge profile and back cavity depth. Nevertheless, some applications can involve a material choice or plate thickness values invalidating the rigidity assumption. In such cases, additional absorption peaks are observed in the absorption frequency spectrum, which cannot be explained by the classical micro-perforated plate theory. The vibro-acoustic coupling of the flexible plate and the acoustic medium has to be taken into account. This is done by a thin shell model employing a patch-impedance approach, modeling each perforation separately. Using this model, absorption coefficient values are calculated for various combinations of plate thickness, perforation diameter and perforation distribution. The results of this study provide a better understanding of the influence of the design parameters of flexible micro-perforated panels on the sound absorption. The method is numerically efficient and can be used for optimizing the acoustic absorption of such panels.
Concepts of timbre emerging from musician linguistic expressions
Authors: Saitis Charalampos , Weinzierl Stefan
Published: June 2017

The metaphorical nature of the lexicon used by musicians to describe timbral qualities of instruments shows that they are not familiar with describing sound as a sensory experience in an acoustical terminology and share little knowledge about the perceptual dimensions of sound. Instead, they conceptualize and communicate sound qualities through different sensory domains, for instance, a sound felt, seen, or tasting as “velvety.” These metaphorical linguistic structures are central to the process of conceptualizing timbre by allowing the musician to communicate subtle acoustic variations in terms of other, more commonly shared sensory experiences. Their psycholinguistic analysis can be considered as one way to study the underlying cognitive representations empirically. An online listening test using short instrumental solo excerpts from recorded music was designed to obtain a rich corpus of free-format verbal descriptions of violin, clarinet, piano, and guitar timbre from instrumentalists describing their own as well as other instruments. Through linguistic analysis, associated with psychological theories of perception and sensory categorization, the emerging instrument-dependent and -independent conceptual structures are extracted as a first step in translating the semantics of musician expressions into perceptually meaningful descriptors of sound quality.
Acoustical coupling between two guitars, onset variation, and timbre perception
Authors: Mores Robert
Published: June 2017

Acoustical coupling between simultaneously played musical instruments has been observed at times, for instance, between adjacent organ pipes [F. Trendelenburg et al., Akustische Zeitschrift 7-20 (1938)]. The observation here concerns two guitars that reveal a different timbre when played simultaneously (A) in contrast to when played separately with the tracks being mixed afterwards (B). Alternatively, the two guitars are played separately but each with a simultaneous steady-state tone presented by a speaker while the frequency relates to the key (C). Subjects rated the music produced under the paradigms A and C as being similar and music produced under the paradigms A and B as being dissimilar, likewise for B and C. The differences were attributed to timbre. For analysis, a mechanical plugging mechanism replaces the musician on the first guitar, whereas the second guitar is replaced by a steady-state tone. While most of the partial tones remain unaffected, partial tones above 3 kHz rise more sharpely and reach higher levels during onset when a simultaneous tone is present compared to when it is absent. Although these partial tones decline rapidly and finally progress toward comparable levels with and without the simultaneous tone, the perceived timbre differs noticeably.
Absolute pitch is disrupted by an auditory illusion
Authors: Deutsch Diana , Edelstein Miren , Henthorn Trevor
Published: June 2017

Absolute pitch (AP) is the rare ability to name a musical note in the absence of a reference note. Here we show that AP possessors sometimes name notes incorrectly in accordance with an auditory illusion. AP possessors were presented with a test tone, which was followed by six intervening tones, and then by a second test tone. The test tones were either identical in pitch or they differed by a semitone. All tones were sine waves.The AP possessors were asked to ignore the intervening tones, and to name both the first and the second test tones after hearing the full sequence. In one condition in which the test tones differed, a tone that was identical in pitch to the second test tone was inserted in the intervening sequence. For example, if the first test tone was D and the second test tone was D#, the note D# was inserted in the intervening sequence. In this condition, the AP possessors showed a significant tendency to misname the first test tone as having the same pitch as the second test tone. This is the first study showing that AP possessors can be induced to misname notes in certain contexts.
A day in the noisy life of a student musician
Authors: Smith Kieren H. , Neilsen Tracianne B. , Grimshaw Jeremy
Published: June 2017

In conservatories and universities across the world, students prepare to be the next generation of performing professionals to entertain and enliven worldwide audiences. They pack numerous musical activities into each school day, from countless hours of personal practice to regular ensemble rehearsals to lessons and performances and other personal activities. Many of these activities expose the musicians to significantly high sound levels and potential threats to long-term hearing health. In order to understand the daily student musician noise experience, music majors at Brigham Young University were selected from various instrument categories to wear a Larson Davis noise dosimeter and their noise levels were recorded for two days. Each musician wrote a log of the times different activities took place as well as the location in which they were performed. Overall daily noise dosages and contributions to the noise dosage from each separate activity were calculated. Doses for each instrument type as well as each activity type were compared to identify which instruments and activities contribute most to noise overexposure.
Measurements and perceptions of interactions between musicians and cellos
Authors: Wofford Timothy , Fritz Claudia , FABRE Benoit , Chouvel Jean-Marc
Published: June 2017

Measurement of physical properties alone has failed to predict how an instrument will be perceived by musicians. Physical properties are only capable of characterizing an instrument as an object. They are not enough to characterize the suitability of the object as an instrument for producing music by a particular musician. To evaluate an instrument, the musician must apply gestures to the instrument and interpret the response of the instrument to those gestures. Two musicians may use different gestures, receive different responses, and thus have a different set of interactions upon which to base their evaluation. This could explain why musicians disagree over instrument evaluations. To study the relationships between gestures, responses, and the perception of interactions in the context of evaluating cellos, we have put in place (1) a motion capture system for measuring the control parameters and (2) a set of piezoelectric sensors to measure the string vibrations of each string. Gestures and string vibrations were measured during the evaluation of two cellos by a few cellists. These measurements are interpreted in the light of the perceptual evaluations.
The influence of cellist's postural movements on their musical expressivity
Authors: Roze Jocelyn , Aramaki Mitsuko , Kronland-Martinet Richard , Ystad Solvi
Published: June 2017

A particularly fascinating aspect of musical expressivity concerns the relationships between the musician’s body and acoustical signal features of the sounds produced by the instrument. Numerous studies have demonstrated this connection, referring to embodied musical cognition, not only through well-studied instrumental gestures directly responsible for the sound production, but also through the use of more indirect and ingrained ancillary movements. Our actual project aims to better understand the influence of these postural adjustments on the expressive musical interpretation for the cello instrument. To this aim, we conducted an experiment involving several professional cellists subjected to various kinds of postural constraints, and analysed the influence of these constraints on sound signal features by comparing constrained and natural playing situations. The results reveal that the cellists’ body movements play an important role during performance. In fact, the torso and especially the head movements appear to insure the metric coherence with the bowing gesture as well as an expressive musical phrasing and rich timbre variations. Finally, we explored more in depth the harsh notes frequently occurring in the most constrained condition, and drew correlations between this timbral degradation and bowing and postural features, with the aim of proposing new pedagogical tools for beginners.
Playing frequency of conical reed instruments
Authors: Kergomard Jean , Guillemain Philippe , Vergez Christophe
Published: June 2017

Several factors explain the difference between the resonance frequencies of the resonator of reed instruments and their playing frequency: the flow rate due to the reed displacement, the reed dynamics, the resonator inharmonicity, and the temperature gradient. For conical instruments, the truncation of the cone entails non-negligible inharmonicity effects. This is true even if the inharmonicity is reduced by a proper choice of the mouthpiece volume. The playing frequency was calculated by using a minimum, ab initio model of self-sustained oscillations, and compared to analytical results. Furthermore, the “reactive power rule” (Boutillon, 1989) provides a link between the pressure spectrum and inharmonicity. Compared to the natural frequency of the complete cone, which is a well known approximation, the playing frequency is slightly higher: typical discrepancies are 50 cents for short truncated cones (higher notes) and 10 cents for long truncated cones (lower notes). This discrepancy, due to inharmonicity, depends on the excitation parameters, and the influence of the second and third harmonics is found to be significant.
Noise pollution from road traffic noise in Rome: Incidence of coronary and cardiovascular events
Authors: Ascari Elena , Licitra Gaetano , Ancona Carla
Published: June 2017

This work focuses on the preliminary results of the research “Noise and health pollution from road traffic and incidence of coronary and cardiovascular events in three Italian cohort studies.” Outcomes of noise simulations on the Rome agglomeration are reported on the whole territory (1285 km2): grid map and noise levels at residential buildings have been calculated according Directive 2002/49/EC method. Population exposure has been linked according a specific protocol that is detailed in the work. Exposure evaluations for epidemiological studies requires assigning noise levels to population according the probability of being exposed to a specific level in the dwelling. Limitations of simulations will be analyzed and associated uncertainty will be estimated, basing on the modeling choices performed. Therefore, uncertainty of linked epidemiological outcomes will be also discussed. First outcomes of incidence of coronary and cardiovascular events in Rome will be presented. Finally, expected results on the three Italian cohort studies will be briefly explained.
New methods for measuring and correlating transportation noise frequencies with ultrafine particulate emissions under varying meteorological conditions to inform environmental health studies
Authors: Leaffer Douglas J. , Malik Rafia , Tracey Brian , Gute David M. , Hastings Aaron L. , Roof Christopher J. , Noel George J.
Published: June 2017

Transportation-derived particulate matter and chronic noise exposure frequently occur concomitantly in urban areas. Noise is an important confounder to be evaluated in epidemiological studies, yet few public health studies have included both air pollution and noise in health effects models due to difficulty in demonstrating epidemiologic causal mechanisms and confounding factors in noise and air pollution sampling and analytical methodologies. This study will present a framework for the development of a traffic-noise frequency and particulate emissions correlation model based on frequency-domain analysis of vehicle noise measurements, compared with particulate measurements sampled concurrently at two Greater Boston urban neighborhoods under varying meteorological conditions. The research will present new methods for evaluating bi-seasonal measurement of both transportation noise and associated particulate emissions, with emphasis on Ultrafine Particulates (UFP, <100 nm diameter) from diesel exhausts. The goal of the paper is to develop a preliminary model demonstrating correlations between transportation source noise frequencies and UFP. The importance of this research is to establish a methodology to disentangle health-based receptor impacts from both pollutants under varying scenarios where meteorological parameters are not favorable for particulate transport to receptors, yet noise is measurably present.
Advances regarding a new method for measuring the in situ noise abatement performance of urban noise reducing devices
Authors: Jolibois Alexandre , Defrance Jérôme , Jean Philippe
Published: June 2017

Recent works regarding urban noise reducing devices have clearly shown the interest of such solutions in order to improve the sound quality in urban areas. To accompany the development of new products, it now becomes necessary to provide a technical regulatory framework for all stakeholders (manufacturers, city planners, consulting acoustical engineers, etc.) in order to guarantee quality, efficiency, and compliance with urban implementation requirements. This is the main purpose of the technical group CNEA-U, affiliated to the French commission for standardization of road traffic noise reducing devices. As part the technical group activities, a new method for measuring the in situ noise abatement performance of urban devices adapted to the urban context has been developed. The purpose of the method is to provide an indicator of the noise reduction effect of a particular product, measurable in situ but depending as little as possible on environmental effects. To reach this purpose, the parameters of the method have first been studied numerically and optimized. Then the method has been tested experimentally with several industrial prototypes in a controlled environment. In this paper, the framework of the method as well as results of preliminary analyses are presented and discussed.
Informing the public on noise impacts through the WEB-GIS DYNAMAP software application
Authors: Peruzzi Laura , Bellucci Patrizia , Cerniglia Andrea , Coppi Paola
Published: June 2017

Public information on noise impacts is one of the most problematic objectives of the environmental noise directive 2002/49/EC that authorities responsible for providing strategic noise maps should provide. In order to facilitate public information, a web-gis software application has been developed within the Dynamap project. The DYNAMAP project is a LIFE project aiming at developing a dynamic noise mapping system able to detect and represent in real time the acoustic impact due to road infrastructures. To that end, the project involves the development of customized low-cost sensors and communication devices, as well as the implementation of an advanced management and reporting interface to update noise maps and inform the public on noise issues. To guarantee the full effectiveness of this application, a group of selected users will be monitored to check the accessibility of the system and help developing a user-friendly interface for public information. Tests will be also administered to the general public to evaluate the system versatility and its contents comprehensibility. In this paper a detailed description of the web software application, of the indicators used to ease public information and of the tests prepared to check recipients ability in managing and consulting the system is given.
Effects of noise for workers in the transportation industry
Authors: Burgess Marion , Molesworth Brett
Published: June 2017

There are many work environments in the transportation industry where the employees are required to perform tasks that require a high level of concentration and attention in a noise environment that is below a damage risk level but above an acceptable level for office workers doing similar challenging tasks. Pilots, bus, truck, and train drivers all need to make safety critical decisions and operate technical equipment in the presence of continuous noise generated from their vehicles engine/s. Transport check-in staff need to communicate and process passengers in noisy check-in halls. In this paper, we will discuss findings from a number of studies investigating the effect on various cognitive and memory skills of noise similar to that experienced by workers in transportation. The studies have considered the interactions of noise type, i.e., wideband noise or babble noise, signal to noise ratio, and language background on cognition processes, including working and recognition memory. The results highlight the detrimental effect of broadband noise on both working memory and recognition memory.
The electric power being generated may be a key variable in the sensing of wind farm operations
Authors: Schomer Paul D.
Published: June 2017

This entire assessment method is based on a series of statements and conclusions from those statements. The basic premise is that sound flowing through the cochlea is not the source of problems below the threshold of hearing. That statement leaves two of what I will call “technical possibilities.” One possibility is that there are pathways other than through the cochlea for the infrasound to get to the brain. A second possibility is that to date we have missed something in the audible sound range that is the source of problems or that both of these situations exist. This paper falls in the category of something missed in the audible range. It develops a theory that the electric power being generated is the dominant factor in people’s response, not acoustic level. People can see and hear a turbine running, but they cannot know the power being generated. A diary study would list times people were home and the times they could detect the sensation. Correlation between electric power level being generated and subject responses would be particularly meaningful because they would be responses without the subject having knowledge of the electric power being generated.
A possible noise criterion for wind farms
Authors: Schomer Paul D. , Pamidighantam Pranav K.
Published: June 2017

Opposition to wind farm noise is not abating and shows no sign of doing so in the future. In a January 2017 paper in Sound and Vibration, Hessler, Leventhal, Walker and Schomer come together to report that independently they have come to about the same conclusion for a proper threshold of wind turbine noise. The same A-Weighted criterion has shown to come up in a variety of independent ways. This paper is not for pie in the sky desires for no sound. Rather, it attempts to map sound from a common source such as road traffic noise to the sound from wind farms. We do this calculation in two ways: using percent highly annoyed set to 6.5%, roughly 58 DNL dB for road traffic. In the second method, we developed the CTL for the comparative sources and it is the difference in CTL that shows the adjustment from one source to the other. Our conclusion is that the criterion for wind turbines should be 36-38 dB(A).
On translating minimum siting distances into percentages of receiving properties meeting a stated dB(A) criterion
Authors: Pamidighantam Pranav K. , Schomer Paul D.
Published: June 2017

Around the world, minimum siting distances are used by regulators and developers to limit the effects of wind turbine noise on people. Acousticians know that the proper calculation is equal sound level contours, but customers, in this case the communities, developers, and regulators, all want simpler solutions. When creating limits for most industrial sources, noise levels from the source decrease monotonically with distance. For wind farms, the observing can be done from within the source and a monotonic function can no longer be assumed. This study makes use of data collected at over 1200 dwelling units as a part of the Health Canada Study. This paper provides a method to determine minimum siting distances based on predicted percentages of exceedances of dB(A) criterion at dwellings. A Riemann sum using CTL as a basis creates a model that can be applied to find acceptable minimum siting distances.
Reproduction of wind turbine infrasound and low frequency noise in a laboratory
Authors: Cooper Steven E.
Published: June 2017

The use of large baffle speaker system to produce infrasound/low frequency noise from wind turbines for subject medical testing was found to have issues in reproducing the original recorded signal. Reproducing the original transient time signal was not achieved. The use of synthesised signals for subjective testing of infrasound was examined and is discouraged when compared to actual real world sound files. The results of the testing and recommendation to use medical studies in the field rather than laboratory testing is discussed.
Measurement techniques for determining wind turbine infrasound penetration into homes
Authors: Metelka Andy
Published: June 2017

Previous measurements using advanced measurement instrumentation and Narrowband 3-dimensional FFT based signal processing indicate the presence at infrasonic blade pass frequencies in dwellings from multiple turbines. New measurements include both near and extreme far field detailing that some homes are highly susceptible while others are not. Proposed calculations for transmissibility are outlined with simultaneous long-term measurements at 4 homes. Various locations inside homes are also compared to outside measurements relating wind speed, wind direction and other audible SLM parameters.
Background noise variability relative to wind direction, temperature, and other factors
Authors: Pellerin Patricia
Published: June 2017

Characterization of the ambient acoustic environment is often a critical component in the wind energy permitting process. Collection of ambient data may be required during the pre-construction or post-construction phases to establish a baseline for determining wind turbine sound contribution at different points of reception. The challenge with establishing that baseline is that ambient sound levels continuously fluctuate, affected by multiple factors including existing sound sources, human activity, and meteorological parameters like wind speed and direction. This continuous fluctuation makes both definition and reproducibility of ambient conditions difficult. This paper examines meteorological data collected during surveys at numerous wind energy facilities throughout the United States. Meteorological data were collected at different heights above ground level using a combination of multiparameter weather sensor stations deployed during survey periods as well as other meteorological towers in proximity to the wind energy facility sites. Relationships between ambient sound level data and various meteorological parameters including wind speed, direction, temperature, and relative humidity are reviewed and analyzed.
Meteorological reanalysis data inputs for improved aircraft noise modeling
Authors: Romond Rachel A. , Sparrow Victor
Published: June 2017

In order to improve the prediction capabilities of aircraft noise modeling tools, recent work has focused on including measurements of the vertical structure of the inhomogeneous propagation environment. Meteorological reanalysis incorporates quality-controlled measurements from many sources into atmospheric models, which produce 4-D data fields describing the state of the atmosphere. In this work, reanalysis products are considered for use in the calculation of aircraft noise propagation from en-route and lower altitudes to the ground. Atmospheric profiles are extracted from the NCDC/UCAR Climate Forecast System Reanalysis (CFSR) and input to an acoustic raytracing model to demonstrate effects of realistic inhomogeneous atmospheric conditions throughout the propagation path. Results will be discussed, as well as practical and methodological considerations for data integration. The techniques demonstrated for this data set should also be applicable for other similar data sets, and thus may be useful in the future development of the Federal Aviation Administration's (FAA) Aviation Environmental Design Tool (AEDT). [Work supported by the FAA. The opinions, findings, conclusions, and recommendations expressed in this material are those of the authors and do not necessarily reflect the views of ASCENT FAA Center of Excellence sponsor organizations.]
Noise mapping based on participative measurements with a smartphone
Authors: Picaut Judicaël , Aumond Pierre , Can Arnaud , Fortin Nicolas , Gauvreau Benoit , Bocher Erwan , Palominos Sylvain , Petit Gwendall , Guillaume Gwenaël
Published: June 2017

Because noise is a major pollution leading to non-negligible socio-economical impacts, many national regulations aim at reducing the population noise exposure. Within the context of the European directive 2002/49/EC, a special attention is paid to the evaluation of the existing noise environment. Nowadays, this assessment is addressed based on simulated noise maps, which however present some limitations due to the simplification of noise generation and propagation phenomena. Smartphone participative measurements are alternatively being developed, offering the high temporal and spatial granularities recommended by the EU directive. However, the existing approaches often lack a quantification of the produced noise maps accuracy, and are rarely user-oriented. In this context, within the framework of the EU project ENERGIC-OD, a Spatial Data Infrastructure (SDI “OnoMap”) has been developed to manage smartphones measurements using a dedicated Android application (“NoiseCapture”) and to produce relevant noise maps. In the present communication, this infrastructure is detailed, with a specific attention to the following major key points: data management and qualification from its production to its dissemination, use of standards for data interoperability, optimization of noise measurements, production of 24h noise maps based on measurements distributed over a day, integration of a confidence index on the produced data.
Simulation of elastic wave propagation in heterogeneous materials
Authors: Van Pamel Anton , Sha Gaofeng , Rokhlin Stanislav I. , Lowe Michael J.
Published: June 2017

The propagation and scattering of elastic waves within heterogeneous materials is of wide interest in seismology, medical ultrasound, and non-destructive evaluation. The attenuation and noise caused by scattering can be a hindrance, limiting the interrogation of features within the material, or it can be used to measure the properties of the material. In both cases, the possibility to perform accurate simulations is hugely attractive in order to develop the exploitation. Until now, most modeling of wave propagation in these media has been limited to analytical methods based on low-order scattering assumptions, or numerical simulations in two dimensions or small domains. But it has recently become possible to perform accurate three-dimensional Finite Element simulations in significant sample volumes. This talk will present the deployment and validation of such a model, developed by the authors, and believed to be the first quantitative simulation of this kind. Predicted attenuation and wave speed dispersion will be shown to compare well with values obtained from established scattering theory with accurate accounting of the second order statistics of the material system. The results provide new and independent insights and the new modeling capability will facilitate future investigations into the physics of the propagation and attenuation phenomena.
Ultrasound field structure simulation in acousto-optic cells with acoustic beam reflection
Authors: Mantsevich Sergey , Balakshy Vladimir , Molchanov Vladimir , Yushkov Konstantin
Published: June 2017

Some part of the acousto-optic devices fabricated from various crystals applies acoustic wave reflection from one of the crystal facets to arouse the wave with characteristics needed. The acoustic wave is at first aroused by piezoelectric transducer. It propagates along some direction and reflects from the acousto-optic cell face. The face orientation gives the possibility to obtain desired acoustic wave after the reflection. The reflection may be accompanied by the change of the acoustic mode type. The reflection process affects the acoustic beam structure causing the redistribution of acoustic energy inside the beam and the inclination of wave fronts. In this research the influence of acoustic beam reflection on the acoustoc field structure in the quasi-collinear acousto-optic cells fabricated from the tellurium dioxide crystal is examined and compared with acoustic beam reflection in collinear acousto-optic cell fabricated from the calcium molybdate crystal. Tellurium dioxide crystal has extremely strong acoustic anisotropy while calcium molybdate may be considered as acoustically isotropic media. The examined problem is solved using the original method when the media acoustic anisotropy influence on every component of ultrasound beam angular spectrum is taken into account. The presented research has also the applied importance as acoustic field structure influence on the acousto-optic devices characteristics. [This research was supported by the RSF grant №14-22-0042.]
Soft porous materials with ultra-low sound speeds in acoustic metamaterials
Authors: Brunet Thomas , Poncelet Olivier , Aristégui Christophe , Leng Jacques , Mondain-Monval Olivier
Published: June 2017

Porous media have unique acoustic properties that have been intensively studied for many decades and found many applications in various areas. Owing to their low sound speed, porous materials have proven to be interesting key elements for the realization of acoustic metamaterials since they may act as strong Mie-type resonators, when shaped as spherical particles [1]. In that context, soft porous silicone rubbers are ideal “ultra-slow” materials since a sudden drop of the longitudinal sound speed cL with the porosity Φ has been observed in these porous materials (cL < 100 m/s for Φ < 10%). Such unusual behavior is well captured by simple models based on low-frequency approximations of multiple scattering theories [2]. Then, I will discuss the interest of these “ultra-slow” particles for acoustic metamaterials of which the acoustic index has been shown to be negative [3]. At last, I will demonstrate that the exotic values of the acoustic index may be tuned by using other porous particles such as xerogel beads [4]. [1] Brunet et al., Science 342, 323 (2013). [2] Ba et al., Scientific Reports 7, 40106 (2017). [3] Brunet et al., Nature Materials 14, 384 (2015). [4] Raffy et al., Advanced Materials 28, 1760 (2016).
Anomalous transport of ultrasound in a strongly scattering inhomogeneous medium
Authors: Kerhervé Sébastien O. , Page John H. , Skipetrov Sergey
Published: June 2017

Investigating the propagation of multiply-scattered waves in disordered materials allows the characterization of heterogeneous media and may reveal anomalous wave properties. We study wave transport in a deceptively simple system consisting of closed packed aluminum beads surrounded by low viscosity silicone oil, in which ultrasonic waves undergo many scattering events without incurring significant dissipative losses. Using ultrasonic pulsed transmission experiments, the small ballistic pulse at short observation times was separated from the much larger multiple scattering coda that extends over a wide range of arrival times, enabling the scattering strength to be assessed as a function of frequency and giving values of kls (wave vector times scattering mean free path) between 4 and 10. Based on kls, the propagation of the multiply scattered waves is expected to be well described by the diffusion approximation. However, this is not the case, and the observed behaviour suggests the presence of two coupled modes of propagation: a fast component traveling through the liquid and a slower component traveling through the bead network. The results are interpreted by developing a model for the coupled propagation of a diffusive component and a “renormalized” component that is described using the self-consistent theory of localization.
Benefits of wearing hearing aids in a natural complex auditory environment
Authors: Hafter Ervin , Xia Jing , Pentony Shareka , Nooraei Nazanin , Ahmann Brianne , Kanungo Ishan , Kalluri Sridhar
Published: June 2017

A simulation of multi-talker environments (Hafter et al., Basic Aspects of Hearing. 2013) asks subjects to process a continuous flow of information from spoken stories. Subjects respond manually to visually-presented questions that appear soon after occurrence of the relevant information in one of the stories. In the present study, hearing-impaired listeners either do or do not receive gain through their hearing aids, and special interest is in responses to questions based on phonetic cues vs. those which require semantic analysis of the acoustic signal. Our aim is to determine the benefit of receiving hearing-aid amplification, comparing the benefit observed for phonetically based questions to that observed with semantically-based questions, and in terms of individual linguistic and cognitive abilities as measured by frequently used tests for the purpose. Results showed a strong benefit of aided listening among subjects when the need is only to recognize speech but, large individual difference in aided benefits when the listener was required to understand the meaning of the speech, with auditory, linguistic and cognitive capabilities all being factors that determine successful understanding. The incorporation of naturalistic elements in the simulation of multi-talker listening is important for unearthing the large individual variability in communication success.