bluuebunny/crossref_metadata_2025 huggingface dataset:
S&N-S Light: An anthropic noise control device to reduce the noise level in densely occupied spaces encouraging personal control of voice
Authors: Di Blasio Sonja , Calosso Giulia , Puglisi Giuseppina E. , Vannelli Giuseppe , Corbellini Simone , Shtrepi Louena , Masoero Marco C. , Astolfi Arianna
Published: June 2017

Recently, in many fields related to environmental quality, such as thermal and visual quality, the tendency is to customize the comfort according to the user’s needs. A tailored comfort zone is planned in public spaces, in which occupants can set their own comfort level with passive or active systems. In this context, the reduction of noise due to anthropic sources can be seen as a priority. In densely occupied spaces, such as classrooms, workplaces, restaurants, and outdoor spaces, the noise due to users chatting has a detrimental effect upon performance, health, and environmental quality. This study reports applications of S&N-S Light, Speech & Noise Stop-Light, a patented smart phonometric device with a warning light activation of exceeding of predetermined anthropic sound levels limits, which encourages personal voice control through visual feedback. The light activation, with green, yellow, and red color, is based on an adaptive algorithm that accounts for pre-defined statistical noise levels; therefore, accidental noise levels can be filtered. The device has been used in classrooms, restaurants, and urban squares. Results indicate a decrease of noise levels with S&N-S Light, especially when the occupants received training about the device benefits.
Designing triangular diffusers for architectural acoustics
Authors: Cox Trevor J. , D'Antonio Peter
Published: June 2017

Pyramids and wedges can be used to change how sound is reflected in concert halls and other performance spaces. Simple geometric acoustic models can explain the reflection behavior when the wavelength of sound is small compared to the dimensions of the faces. Depending on the angle between adjacent surfaces, considerable dispersion, moderate diffusion, or specular reflection can result. There will be a bandwidth where geometric models are inaccurate because diffraction will be significant. Consequently, this study uses 2D Boundary Element Methods (BEMs) to overcome the wavelength limit. It is assumed that the understanding from 2D triangles can be generalized to 3D surfaces such as pyramids. A numerical optimization process is used to design arrays of triangles, examining the effect of depth, asymmetry, and periodicity. The performance for shallow and deep surfaces will be presented for different incident sound fields.
Experience obtained during the ten years of the sound classification practical use for regulation building acoustics in Lithuania
Authors: Jagniatinskis Aleksandras , Fiks Boris , Mickaitis Marius
Published: June 2017

Advantages of application the sound classification schemes were foreseen in the two applications. In the legal regulation, the scheme expresses in the users friendly and easy understandable form protection against noise requirements for the buildings. The scheme is also a tool for designer to advice criteria of the suitable acoustic comfort in premises and also to label buildings according acoustic quality. Classification scheme implemented in Lithuania comprise five acoustic comfort classes—A, B, C, D, and E. Acoustical requirements expressed by the C sound class limit values correspond to the at least acceptable acoustic comfort level. The lowest (worst) sound class is E and comprise limit values corresponding to the acoustical comfort level in old buildings erected under sound insulation requirements existed before. By this reason, the step in limit values between different classes cannot be permanent and depends from the changes in acoustical demands during the time. For enforcement, legal requirements expressed through mandatory sound class C for new dwellings and E for renovated buildings from 2007 pre-completing testing become mandatory. In this approach, more important becomes a guideline for verification of compliance with an acoustic class.
Revision of the Swedish sound classification scheme for premises
Authors: Larsson Krister
Published: June 2017

The Swedish building code puts requirements on noise protection in new buildings. For residential buildings, minimum requirements are given directly in the building code, and demands for better acoustic quality are given in a sound classing scheme according to the Swedish Standard SS 25267, which has been revised in 2015. For premises, such as offices, schools, or hotels, the building code does not contain specific quantified minimum requirements on the acoustic properties, but refer instead to the sound classing standard SS 25268 for tabulated values. Sound class C corresponds to the minimum requirements for new buildings, and demands for better acoustic quality are given according to class B or class A. The sound classing standard for premises, SS 25268, is currently under revision, and during the last years, the needs for changes and updates have been collected in cooperation with stakeholders and experts. The paper presents the motivations for the revision and the status of the work. Ideas for major revisions are being discussed such as suggestions for improved room acoustic requirements in schools, as well as sound insulation and acoustic comfort in open plan offices.
A pilot study on acoustic regulations for office buildings—Comparison between selected countries in Europe
Authors: Rasmussen Birgit
Published: June 2017

Acoustic regulations or guidelines for office buildings are found in several countries in Europe. The main reason is to ensure satisfactory acoustic working conditions for the various tasks and activities taking place in the many different kinds of rooms in such buildings. Examples of room types are offices, meeting rooms, open-plan offices, corridors, reception areas, dining areas, all with different acoustic needs. Some countries specify a few acoustic limit values only, while others define several different criteria, guidelines only, or a combination of requirements and guidelines. As a pilot study, comparison between requirements in selected countries in Europe has been carried out. The findings show a diversity of limit values for acoustic requirements. The paper includes examples of requirements for reverberation time, airborne and impact sound insulation, noise from traffic and from service equipment. Examples of guidelines will also be presented. The discrepancies between countries are being discussed, and some priorities for adjusting acoustic regulations will be given. In addition to a set of regulations or guidelines, some countries have office buildings included in national acoustic classification standards with different acoustic quality levels. The paper will indicate examples of such classification criteria for comparison with acoustic regulations.
Studies of rhythmic synchronization in avian vocal learners using operant conditioning methods
Authors: Seki Yoshimasa , Okanoya Kazuo
Published: June 2017

Researchers have argued that non-human animals exhibit a sense of rhythm. Budgerigars and Bengalese finches were trained to peck a key iteratively in response to metronomic stimuli using an operant conditioning method. Peck timing in Budgerigars was distributed around the stimulus onset of the metronome, suggesting the birds synchronized their body movement to the rhythm of the metronome. However, peck timing in finches appeared to correspond to an estimated reaction time, suggesting that peck responses were a mere reaction to the metronome stimuli. Next, budgerigars were trained to peck two keys alternatively without any metronomic stimuli, so that pecking of the keys was self-paced. Metronomic sounds were created to match the intervals of the self-paced pecking. Additional metronomic stimuli were created to be 10% faster, 10% slower, and 20% slower than the original self-paced metronome stimuli for each bird. These sped up or slowed down metronomic sounds were played back in the background of the self-paced pecking task. In this experiment, rhythmic synchronization was not observed; however, one bird exhibited shorter pecking intervals for the faster metronome and longer intervals for the slower metronome, suggesting that the metronomic stimuli influenced peck timing in this bird in the absence of training.
Micro-scale habitat use of humpback whales around Maui Nui, Hawaii
Authors: Kügler Anke , Lammers Marc
Published: June 2017

Each winter, thousands of North Pacific humpback whales (Megaptera novaeangliae) migrate from their high latitude feeding grounds in Alaska to mate and calve in the shallow tropical waters around the Main Hawaiian Islands. Previous studies on humpback whales in Hawaii have focused on the whales’ acoustic behavior and their general distribution within the islands, but little is known about small-scale habitat preferences. Off the island of Maui, anecdotal reports from commercial operators and researchers tell of clusters of whales within the breeding area. However, to our knowledge, no studies have been conducted to examine the phenomenon of micro-scale aggregations. A pilot study using passive acoustic monitoring with Ecological Acoustic Recorders (EARs) was conducted from January through early March 2016 at three sites off Maui, using male singers as a proxy for relative whale abundance. Root-mean-square sound pressure levels (SPLs) were calculated to compare low frequency acoustic energy (0-1 kHz) between the different sites. Preliminary results indicate that singers alternate between the two farthest sites. Further, different diel patterns in song activity where observed among the sites. These results suggest at least some degree of variable spatial and temporal habitat use and that further monitoring is warranted.
Acoustic measurements of sediment transport. From pulse-coherent Doppler to an autonomous bathymetry vessel
Authors: Traykovski Peter
Published: June 2017

In this talk, we present recent advances in sediment transport research using high frequency acoustic sensors. The topics covered will range from development and use of a multifrequency pulse-coherent Doppler system to measuring bathymetry with unmanned autonomous surface vessel (ASV) equipped with a state-of-the-art swath bathymetry sensor. The pulse coherent Doppler was able to measure velocity profiles through the wave boundary layer in a high concentration fluid mud layer off the coast of Louisiana. At the end of energetic wave events, as the forcing decreased, the acoustic measurements revealed the settling of the mud layer with transition from turbulent to laminar flow, and a four order of magnitude increase of the viscosity of the mud and water fluid. This increase was inferred from the vertical structure of the wave boundary layer and offers a unique in-situ non-invasive approach to measuring the viscosity of flows with complex rheology. The ASV measurements allow O(10 cm) resolution bathymetric measurements in energetic tidal environments, where navigation of manned vessels on accurate track lines suitable for repeat bathymetry measurements is difficult, and are providing new insights into the dynamics of tidal inlets.
Relating acoustic and optical measurements to particle and floc concentrations in the bottom boundary layer
Authors: Sherwood Christopher R.
Published: June 2017

Profiles of optical and acoustic properties were measured by moving instruments vertically in the bottom boundary layer, between the bottom and about 2 m above the sea floor, at a sandy inner shelf site 12 m deep. Profiles were performed every two hours for 36 days, spanning a range of wave and current conditions. Acoustic instruments on the profiling arm included a three-frequency acoustic backscatter profiler and a 1.5-MHz acoustic Doppler velocimeter. Optical instruments on the arm measured backscatter, attenuation, and absorption. Stationary instruments on the main tripod measured waves, currents, Reynolds stress, and vertical temperature/salinity gradients. The acoustic backscatter measurements were coupled with optical measurements and recent models for the backscattering and absorption by flocs to provide time series of particle-concentration and size profiles. Remarkable changes in particle sizes, concentrations, and inferred densities and settling velocities were observed. These observations demonstrate the value of the traditional Rouse profile assumptions often used in suspended-sediment transport calculation, but also reveal the rich temporal and spatial complexity of the near-bottom particle field.
Ultrasound, shock waves, and phonons
Authors: Pecha Rainer
Published: June 2017

On Dec. 10, 2016, the brilliant experimental physicist Prof. Wolfgang Eisenmenger passed away completely unexpectedly. His extensive work had influence on many different fields of acoustics. This presentation gives an overview on his remarkable and inspiring life and research.
Quantification of the shielding of kidney stones by bubble clouds during burst wave lithotripsy
Authors: Maeda Kazuki , Colonius Tim , Kreider Wayne , Maxwell Adam D. , Bailey Michael
Published: June 2017

Bubble clouds can shield kidney stones from insonification, and limit stone breakage during burst-wave lithotripsy (BWL), a recently proposed technique that uses focused ultrasound pulses with an amplitude of O(1-10) MPa and frequency of O(0.1) MHz. We use numerical simulations to quantify the magnitude of such shielding. In the simulations, we solve for the radial evolution of Lagrangian bubbles coupled to a compressible fluid using volume-averaging techniques. The resulting equations are discretized on an Eulerian grid. In particular, we quantify the reduction in acoustic energy flux incident on a rigid, plane wall that models the stone surface. We consider a burst wave with an amplitude of 6 MPa and a bubble cloud of diameter O(1) mm. The size distribution of nuclei, the number density of bubbles, and the distance of the cloud from the wall are varied, We show that a cloud containing O(10) bubbles with a diameter of O(10) um can reduce the total energy flux by more than 50%, largely independent of distribution of nuclei. Finally, we compare the simulation results with high-speed images and hydrophone measurements of bubble clouds from companion experiments. [Work supported by NIH 2P01-DK043881.]
Variational formulations for elastic inversion from full-field wave data
Authors: Barbone Paul E.
Published: June 2017

Ultrasound elastography uses propagating P-waves to measure the deformation of soft elastic solids, including soft tissues. In some cases, the deformation of interest is quasistatic while in others it is a propagating S-wave. From the measured deformation field, it is of interest to infer the distribution of tissue rigidity and/or shear wave speed distribution within the imaged region. We review several variational formulations that have been proposed to solve this inverse problem, and their respective mathematical properties. The primary focus will be on variational formulations that lead to direct solution of inverse problem. These include the virtual fields method (and the related method of Romano, Shirron, and Bucaro), the direct error in constitutive equation formulation, and the adjoint-weighted variational formulation. We will consider consistency with the original boundary value problem, stability of the variational formulation, and required continuity of both data functions and the unknown modulus distributions. For completeness, we will briefly review three cost functions related to iterative solution of the inverse problem: energy error, error in the constitutive equation (ECE), and stabilized output least squares.
Shear modulus is a good surrogate for total tissue pressure: Preliminary studies with a xenograft pancreatic cancer tumor model
Authors: Doyley Marvin M. , Wang Hexuan , Nieskoski Michael , Pogue Brian
Published: June 2017

Pancreatic ductal adenocarcinoma (PDA) is a common and lethal disease, with a 5-year survival rate of less than 6%. The absence of a functional vasculature and the build-up of dense stromal regions impede drug delivery that prevents the disease from being eradicated, even when surgery is combined with chemotherapy. We hypothesize that real-time measurement of total tissue pressure, as related to cancer cell growth and drug delivery, will enable translational research into patient-specific therapies. Since no imaging methods can measure tissue pressure in vivo, we investigated the feasibility of using elastography to provide a surrogate measure of total tissue pressure. Specifically, we performed studies on orthotopically and subcutaneously grown xenograft tumors (n = 20) to assess how the shear modulus of naturally occurring AsPc-1 pancreatic tumors varies with stromal density. The results of this investigation revealed that there is 6 kPa difference between the shear modulus of orthotopically and subcutaneously grown tumors. A strong correlation was observed between the shear modulus of the extracellular matrix and tissue pressure measured with a pressure probe. We also observed good correlation between shear modulus and collagen density. These preliminary results demonstrate that elastography is a good imaging surrogate biomarker of total tissue pressure.
Elastic reconstruction of shear modulus and stress distribution for assessing abdominal aorta aneurysmal rupture risk
Authors: Mix Doran , Stoner Michael , Richards Michael S.
Published: June 2017

The necessity of surgical intervention of abdominal aorta aneurysms is based on a risk-reduction paradigm primarily relying on trans-abdominal ultrasound (US) measurements of the maximum diameter of an AAA. However, AAA diameter is only a rough estimate of rupture potential and elastographic estimates of material property changes and stresses within aortic tissue may be a better predictor. This work presents an elastic imaging technique to match model predicted displacement fields to those measured using clinical US. A linear elastic finite-element model is used and is assumed to be undergoing a quasi-static, plane strain deformation. This technique uses a regularization scheme to incorporate geometric segmentation information, as a penalty or soft prior, to counter the inherent ill-posedness of the inverse problem. In addition, displacement fields are measured and accumulated over the entire cardiac cycle and incorporated simultaneously in the reconstruction technique to improve the signal to noise of the recovered modulus distribution. Model predicted strain fields and modulus distributions are used to predict the relative stress induced over the cardiac cycle. Results of validation studies comparing modulus and stress fields performed using finite-element simulations of 3D and time dependent geometries, tissue-mimicking phantom simulations, and initial clinical results will be presented.
Acoustic performance of MEMS microphones. Past, present, and future
Authors: Pedersen Michael
Published: June 2017

An overview will be presented of the current state of commercial MEMS microphone technology with focus on acoustic performance metrics such as noise and sound pressure limits, bandwidth, and low frequency behavior. Important limitations for MEMS element and electronic performance will be discussed in the context of the various transducer technologies currently being pursued or offered. The performance of MEMS microphones, since their commercial introduction in the early 2000s, has been strongly driven by the mobile phone handset application, which continues to be the most important market segment by volume. Substantial improvements in performance have been realized since the inception, to meet opposing demands of better acoustic performance and lower power consumption/smaller size. A brief summary of the development trajectory and possible future directions will be given. With the advent of new important applications, such as home automation, and a general movement in design towards digital interfaces, other blends of microphone performance requirements are emerging. A discussion of such requirements and their possible impact on acoustic MEMS design will be provided.
Microphone and microphone array characterization utilizing the plane wave tube method
Authors: Chew Tung Shen , Zhao Arthur , Littrell Robert
Published: June 2017

Microelectromechanical Systems (MEMS) Microphone arrays are becoming ubiquitous in consumer electronics. Large and expensive anechoic chambers are commonly used to characterize these arrays. Individual MEMS microphones, on the other hand, are typically tested using one of three methods: a free field calibration in an anechoic chamber, a pressure field calibration in a pressure chamber, or a pressure field calibration in a plane wave tube (PWT). In this work, we present a PWT system for testing a single microphone as well as a second PWT system for testing an array of four MEMS microphones. Both systems utilize a 3D printed portion of the tube that is designed to minimize reflections and standing waves while allowing the sound pressure to reach a calibrated instrumentation microphone and the MEMS microphone(s) under test. With these PWT systems, we characterize individual microphones up to 30 kHz and microphone arrays up to 3 kHz. Further, the array test system is used to measure the polar pattern of the microphone array at several frequencies and measure the impact of microphone mismatch on array performance. This PWT test methodology is a size and cost effective way to characterize MEMS microphone arrays.
The Graduate Program in Acoustics at the Pennsylvania State University
Authors: Sparrow Victor , Russell Daniel A.
Published: June 2017

The Graduate Program in Acoustics at Penn State is the only program in the U.S. offering the Ph.D. degree in acoustics as well as M.S. and M.Eng. degrees in acoustics. An interdisciplinary program with faculty from a variety of academic disciplines, the Graduate Program in Acoustics is administratively aligned with the College of Engineering and closely affiliates with the Applied Research Laboratory. Research areas include structural acoustics, nonlinear acoustics, architectural acoustics, signal processing, aeroacoustics, biomedical ultrasound, transducers, computational acoustics, noise and vibration control, psychoacoustics, and underwater acoustics. Course offerings include fundamentals of acoustics and vibration, electroacoustic transducers, signal processing, acoustics in fluid media, sound and structure interaction, digital signal processing, experimental techniques, acoustic measurements and data analysis, ocean acoustics, architectural acoustics, noise control engineering, nonlinear acoustics, outdoor sound propagation, computational acoustics, flow induced noise, spatial sound and 3D audio, marine bioacoustics, and acoustics of musical instruments. Penn State Acoustics graduates serve widely throughout military and government labs, academic institutions, consulting firms and industry. This poster describes faculty research areas, laboratory facilities, student demographics, successful graduates, and recent enrollment and employment trends.
Graduate acoustics education in the Cockrell School of Engineering at The University of Texas at Austin
Authors: Haberman Michael R. , Hall Neal A. , Hamilton Mark F. , Isakson Marcia J. , Wilson Preston S.
Published: June 2017

While graduate study in acoustics takes place in several colleges and schools at The University of Texas at Austin (UT Austin), including Communication, Fine Arts, Geosciences, and Natural Sciences, this poster focuses on the acoustics program in Engineering. The core of this program resides in the Departments of Mechanical Engineering (ME) and Electrical and Computer Engineering (ECE). Acoustics faculty in each department supervise graduate students in both departments. One undergraduate and eight graduate acoustics courses are cross-listed in ME and ECE. Instructors for these courses include staff at Applied Research Laboratories at UT Austin, where many of the graduate students have research assistantships. The undergraduate course, taught every fall, begins with basic physical acoustics and proceeds to draw examples from different areas of engineering acoustics. Three of the graduate courses are taught every year: a two-course sequence on physical acoustics, and a transducers course. The remaining five graduate acoustics courses, taught in alternate years, are on nonlinear acoustics, underwater acoustics, ultrasonics, architectural acoustics, and wave phenomena. An acoustics seminar is held most Fridays during the long semesters, averaging over ten per semester since 1984. The ME and ECE departments both offer Ph.D. degree qualifying exams in acoustics.
Graduate Acoustics at Brigham Young University
Authors: Sommerfeldt Scott D. , Blotter Jonathan , Leishman Timothy W. , Thomson Scott L. , Gee Kent L. , Anderson Brian E. , Neilsen Tracianne B. , Strong William
Published: June 2017

Graduate studies in acoustics at Brigham Young University prepare students for jobs in industry, research, and academia by complementing in-depth coursework with publishable research. Graduate-level coursework provides students with a solid foundation in core acoustics principles and practices. A new acoustical measurements lab course provides a strong foundation in experimental techniques and writing technical memoranda. Labs across the curriculum include calibration, directivity, scattering, absorption, Doppler vibrometry, lumped-element mechanical systems, equivalent circuit modeling, arrays, filters, room acoustics measurements, active noise control, and near-field acoustical holography. Recent thesis and dissertation topics include active noise control, directivity of acoustic sources, room acoustics, radiation and directivity of musical instruments, energy-based acoustics, time reversal, nondestructive evaluation, flow-based acoustics, voice production, aeroacoustics, sound propagation modeling, nonlinear propagation, and high-amplitude noise analyses. Recently, the BYU acoustics program has added two faculty members and increased the number of graduate students, who are expected to develop their communication skills, present their research at professional meetings, and publish in peer-reviewed acoustics journals. Graduate students also often serve as peer mentors to undergraduate students on related projects and may participate in field experiments to gain additional experience.
Biomedical research at the image-guided ultrasound therapeutics laboratories
Authors: Holland Christy K. , Mast T. Douglas , Haworth Kevin J. , Abruzzo Todd A.
Published: June 2017

The Image-guided Ultrasound Therapeutic Laboratories are located at the University of Cincinnati in the Heart, Lung, and Vascular Institute, a key component of efforts to align the UC College of Medicine and UC Health research, education, and clinical programs. These extramurally funded laboratories, directed by Prof. Christy Holland, are comprised of graduate and undergraduate students, postdoctoral fellows, principal investigators, and physician-scientists with backgrounds in physics, chemistry, and biomedical engineering, and clinical and scientific collaborators in fields including cardiology and neurosurgery. Prof. Holland’s research focuses on biomedical ultrasound including sonothrombolysis, ultrasound-mediated drug and bioactive gas delivery, development of echogenic liposomes, early detection of cardiovascular diseases, and ultrasound-image guided tissue ablation. Prof. Todd Abruzzo, an experienced neurointerventional radiologist, directs preclinical porcine sonothrombolysis studies. The Biomedical Ultrasonics and Cavitation Laboratory, directed by Prof. Kevin Haworth, employs ultrasound-triggered phase-shift emulsions for image-guided treatment of cardiovascular disease, especially thrombotic disease. Imaging algorithms incorporate both passive and active cavitation detection. The Biomedical Acoustics Laboratory, directed by Prof. T. Douglas Mast, employs ultrasound for monitoring thermal therapy, ablation of cancer and vascular targets, transdermal drug delivery, and noninvasive measurement of tissue deformation.
Acoustics education opportunities at UMass Dartmouth
Authors: Brown David A. , Buck John R. , Payton Karen , Gendron Paul J. , Costa Antonio
Published: June 2017

The University of Massachusetts Dartmouth has a long tradition of research and course offerings in Acoustics and Signal Processing within the Department of Electrical and Computer Engineering dating back to the 1960s. The department has four full-time faculty with funded research programs in acoustics related areas as well as unique research/calibration facilities including a large underwater acoustic test facility and three fully autonomous underwater vehicles. UMass Dartmouth offers B.S., M.S., and Ph.D. degrees in Electrical Engineering with research opportunities and course offerings in fundamentals of acoustics, underwater acoustics, electro-acoustic transducers, medical ultrasonics, signal processing, speech processing, communications, and detection theory. The department works closely with the Center for Innovation and Entrepreneurship (CIE) and many local companies and government research centers. The poster will highlight course offerings and research opportunities. http://www.umassd.edu/engineering/ece/.
Professional and personal interactions with Tom Rossing
Authors: Strong William J.
Published: June 2017

This talk was motivated by time spent in Australia at the University of New England in Armidale, NSW, during the latter part of 1980. My wife and I and our three youngest sons spent five months there while I carried out research on the flute with Neville Fletcher and Ron Silk. As you might suspect from the title of the talk, Tom was also at the University of New England and our times there overlapped. Tom was solicitous of our sons which enriched their Australian experience. Tom's research was concerned with acoustical aspects of percussion instruments. Though discussions of our respective research projects was limited, our shared experience in Australia led to our continuing interaction during the ensuing years. A major part of the talk will consider interactions with Tom at other times and in other places.
Tom Rossing’s influence on our understanding of the acoustics of wind instrument mechanisms
Authors: Braasch Jonas
Published: June 2017

During his outstanding career, Tom Rossing studied the acoustics of every major class of musical instruments. During my first trip to the United States, to participate as a student in the ASA Columbus 1999 meeting, I was given the opportunity to measure my free-reed pipe in Tom Rossing’s lab using his novel laser vibrometer. Like many others, he soon also became my role model for his broad knowledge, scientific depth, and his sheer pragmatism (that enabled him to write so many groundbreaking books). In particular, our generation greatly benefits from his gift for accurately describing the key fundamentals of complex acoustic phenomena based on a traditional understanding of physics and the use of groundbreaking measurement techniques such as laser vibrometry and TV holography. Tom Rossing never separated the hard work required to understand the underlying mechanisms of musical instruments from the cultural importance and delight of listening to and performing music. And so, he reminded everybody, right after 9/11 during the ISMA 2001 conference, that music brings people and cultures together and that our research is needed right now more than ever.
Results of a laboratory round robin for ASTM International Standard E477-13 for duct silencers
Authors: Lilly Jerry G.
Published: June 2017

ASTM International initiated a laboratory round robin in November 2014 to support the development of a precision and bias statement for the recently revised standard E477-13. Two different silencer designs were constructed for testing by 5 participating laboratories. This paper will discuss the revised test method, the test results, and identify future modifications to the standard that should be looked at in the future.
Acoustic standards in audiology education
Authors: Nelson Peggy B. , Schlauch Robert S.
Published: June 2017

Standards are essential for the practice of audiology. Microphones, sound level meters, and all calibration equipment and procedures depend on effective standards. Equipment and methods for assessing hearing function, and for the fitting and evaluation of sensory aids for hearing loss all require the development and refinement of good standards. The involvement of audiologists in standards development is essential for maintaining high quality professional service. Graduate students in audiology are introduced to standards from both American National Standards Institute (ANSI) and International Standards Organization (ISO) during their graduate education at the University of Minnesota. Particular areas include calibration, audiometry, hearing aids, cochlear implants, and noise measurement and exposure. Methods for incorporating standards into graduate education will be discussed.
Sound labels for classifying environment-friendly products—Progress and challenges
Authors: Fiebig André
Published: June 2017

People are permanently exposed to noise caused by numerous products. The environmental awareness increases, the harmful effect of noise on humans is well acknowledged, and at the same time the desire for acoustic comfort rises. Thus, different emission-related labels are introduced as a reference for consumers informing about relevant product emissions. In fact, surveys show that product sound is already one of the top product features regarding the purchase decision. Thus, it seems that fewer emissions of everyday products are beneficial for all—consumers as well as manufacturers, and finally public health. However, most of the current sound labels use only simple noise level indicators and are only optional leading to an insignificant impact on purchase decisions and reducing the benefit of acoustically-friendly products on our acoustic environment. Moreover, several existing sound labels consider only simple minimum specifications and neglect sound quality related aspects at all. The paper provides an overview of the current status of sound labeling focusing on the European market. Moreover, case studies are presented illustrating massive differences in the sound quality of products on the market within the same product category. The limitations of current sound labeling approaches and initiatives are discussed in detail.
Photoacoustic spectroscopy accurately measures atmospheric 12CO2 and 13CO2 concentrations and optical properties of carbonaceous aerosols
Authors: Gillis Keith A. , Zangmeister Christopher , Reed Zachary , Radney James
Published: June 2017

Understanding of today's climate and predictions of future climate require accurate input data to model the energy balance between the sun's irradiance and Earth’s atmosphere, oceans, land, and surface ice. An important driver of climate change is the absorption and scattering of sunlight by carbon-based aerosols (soot, smoke, etc) that have widely-varying, source-dependent, and history-dependent optical properties. We use a resonant photoacoustic spectrometer (PAS) to measure the optical absorption cross-section of various carbonaceous aerosols that we generate and characterize in situ. The photoacoustic signal is directly proportional to the energy absorbed by the particles. When combined with simultaneous measurements of the total extinction using cavity ring-down spectroscopy, we obtain the particles’ wavelength-dependent albedo (fraction of incident light scattered). Another important driver of climate change is atmospheric carbon dioxide, a greenhouse gas. With the remarkable linearity, sensitivity, and resolution of our PAS resonator, we measure the individual concentrations of 12CO2 and 13CO2 in atmospheric samples to determine the isotopic ratio 13C/12C, which gives a clue to its origin. A temperature-controlled portable PAS system continuously monitors the concentration of atmospheric 12CO2 on a NIST rooftop.
Using correlated noise of turbulent flow in a long-wavelength acoustic flowmeter to measure the average flow speed
Authors: Abbott John Paul R. , Gillis Keith A. , Moldover Michael , Gorny Lee
Published: June 2017

Current methods to measure the flow of gaseous emissions from coal-burning power plant smokestacks have uncertainties of 5% to 20%, which is unsuitable if a carbon pricing program is implemented. As part of its Greenhouse Gas and Climate Science Measurements Program, the Fluid Metrology Group at the National Institute of Standards and Technology (NIST) is investigating methods to reduce the uncertainty of flow measurements from smokestacks. In particular, NIST’s scale model long-wavelength acoustic flowmeter (LWAF) uses low-frequency plane waves to measure the average axial flow speed, V, of turbulent fluid flow in a duct with an uncertainty of 1%. To apply this technology to smokestacks, we are investigating cross-correlations of low-frequency flow noise. The spectral density of the measured flow noise is consistent with fluctuations smaller than the duct diameter D for f >> V/D. The amplitude and width of the correlation peak for broadband flow noise is shown to be dependent on V, and a model of this dependence is forthcoming. Our current work, developing this model, includes filtering the broadband data to determine phase shifts, modeling the effects of the radiation impedance, and examining effects on the broadband flow noise spectra. The results of these investigations are presented.
What leads to audio-visual object formation and when is it helpful?
Authors: Maddox Ross K.
Published: June 2017

An important aspect of parsing complicated auditory scenes is forming perceptual objects that correspond to individual sound sources (e.g., a friend speaking). Once formed, an object can be selected from the acoustic mixture and attended. Auditory cognition can be greatly enhanced by a concomitant visual stimulus (e.g., the speaking friend’s mouth movements), but the mechanism or mechanisms underlying that benefit are not well understood. Previous studies have treated auditory and visual stimuli as separate sources of information and found that they are optimally combined. However, we have shown that auditory selective attention can be improved by a visual stimulus that offers no information at all. Our experiments suggest that these benefits are derived from the visual stimulus being bound to the target auditory stimulus into a single cross-modal object through temporal coherence of those stimuli’s features. In this talk we will discuss a model of auditory-visual object formation that allows an uninformative but coherent visual stimulus to aid listening, along with data that suggest performance benefits may be dependent on the similarity of the target and the masker.
Electrophysiological markers of auditory perceptual awareness and release from informational masking
Authors: Dykstra Andrew R. , Shaw Marnie E. , Gutschalk Alexander
Published: June 2017

In complex acoustic environments, even suprathreshold sounds that are faithfully represented in the ascending auditory pathway sometimes go unperceived, a phenomenon termed informational masking. Little is known regarding the large-scale brain dynamics giving rise to conscious perception under informational masking, particularly outside auditory cortex. To examine this question, we combined simultaneous M/EEG with trial-by-trial perceptual reports and anatomically constrained distributed source estimates. Listeners reported the moment at which they became aware of spectrally isolated and otherwise suprathreshold tone streams rendered sometimes inaudible by random multitone masker “clouds.” While all targets elicited early responses in auditory cortex, later auditory-cortex activity (peaking between 150 and 200 ms) was only observed for targets that were detected. A robust P3-like response with distributed sources was observed for the second detected target (immediately preceding listeners' reports), and was greatly diminished or absent for prior and subsequent targets. The results highlight late, distributed aspects of neuronal activity associated with task-related post-perceptual processing (i.e., task relevance), but argue against this activity underlying conscious perception, per se.
A boundary element based method for accurate prediction of the surface pressure cross-spectral density matrix
Authors: Rouse Jerry W.
Published: June 2017

Accurate prediction of the surface pressure cross-spectral density matrix is necessary to predict the dynamic response of a structure loaded by a diffuse acoustic field. The cross-spectral density matrix describes the frequency dependence of the correlation between the surface pressure at all pairs of points on the structure. Most often the cross-spectral density matrix is obtained from either a uniform distribution of incident plane waves or direct application of the diffuse field spatial cross-correlation function. While the method of plane waves is relatively more accurate, especially at low frequencies, the necessary distribution of incidence angles and ensemble size can be problematic. This talk shall present a boundary element based methodology for determining the surface pressure cross-spectral density for any structure and frequency, including the effects of scattering and shielding. The method involves a power spectral density formulation of the boundary element method and takes advantage of the underlying foundations in potential theory. The method can be generalized beyond diffuse fields and can be applied to structures having a known surface impedance.
Sound radiation efficiency of unbaffled plates using an edge source integral equation
Authors: Sahu Kiran C. , Svensson U. Peter , Martín Sara R.
Published: June 2017

The accurate prediction of sound radiation from unbaffled vibrating plates remains a challenging problem. Finite structures make the sound waves diffract off and around the edges, an effect which is particularly strong at low frequencies. This phenomenon can be modeled with an edge source integral equation (ESIE) [A. Asheim, U. P. Svensson, J. Acoust. Soc. Am. 133 (2013) 3681-3691]. The modeling is based on a separation of the radiated sound into a geometrical-acoustics (GA) term, which equals the infinite-baffle solution, and diffraction of first- and higher orders. Expressions for the GA term and first-order diffraction are available explicitly, whereas higher-order diffraction is calculated through the solution of an integral equation. We present a method with a combination of time- and frequency-domain modeling which gives particularly efficient modeling. In this study, the sound radiation efficiency is targeted so only the sound field at the plate is computed. Thereby the numerically challenging receiver positions of the ESIE method at visibility zone boundaries are avoided. The results of the present study are compared with published results [A. Putra, D.J. Thompson, Applied Acoustics 71 (2010) 1113-1125] and close agreement is found, for a number of vibration modes.
Effects of visco-thermal losses in metamaterials slabs based on rigid building units
Authors: Cutanda Heniquez Vicente , Garcia-Chocano Victor Manuel , Sanchez-Dehesa Jose
Published: June 2017

Potential applications of negative-index acoustic metamaterials are strongly limited by absorptive effects of different origin. In this context, we present an investigation of the visco-thermal effects on the acoustic properties of double-negative metamaterials based on specifically designed rigid units with subwavelength dimensions. It is shown that visco-thermal losses dissipate about 70% of the acoustic energy associated to the excitation of monopolar and dipolar resonances, leading to the suppression of negative refractive index. Our numerical simulations based on the Boundary Element Method (BEM) are in excellent agreement with recent experimental data showing the quenching of the double-negative transmission peak. The BEM numerical model, which has been specifically adapted to this purpose, has also been validated against an equivalent Finite Element Method model. We also present the results and discuss the differences of visco-thermal effects on monopolar resonances leading to negative bulk modulus metamaterials, and Fabry-Perot resonances in metamaterial slabs.
Non-reciprocal sound propagation in zero-index metamaterials
Authors: Quan Li , Sounas Dimitrios , Alu Andrea
Published: June 2017

Moving media have recently attracted attention for their ability to break reciprocity without magnetic materials. By spinning air in an acoustic cavity, it was recently shown that it is possible to realize an acoustic circulator [R. Fleury, D. Sounas, A. Alù, Science 343, 516 (2014)], with applications for sonars and medical imaging devices. Here we show that the non-relativistic Fresnel-Fizeau effect at the basis of these mechanisms can be boosted in zero-index acoustic metamaterials, due to their large phase velocity. This is a different scenario than resonant structures, where the Fresnel-Fizeau effect is boosted by the effectively large wave-matter interaction distance, even for large intrinsic refractive index for the moving medium. Our results open a new venue to use zero-index metamaterials, and can become practically important in the realization of non-reciprocal acoustic imaging systems with built-in isolation and protection from reflections.
Nonlinear metamaterial from piecewise discontinuous acoustic properties
Authors: Titovich Alexey S.
Published: June 2017

Numerous metamaterials have recently been designed which exhibit either negative effective density and/or bulk modulus leading to extraordinary wave bearing capabilities. This research increases the design space by considering displacement-dependent properties which are discontinuous over a period of oscillation. Such nonlinear behavior has been studied in dynamical systems with intermittent contact. This work applies those analytical results together with numerical methods to provide insight into the harmonic and subharmonic generation in acoustic metamaterials with properties differing from compression to rarefaction. Stability is analyzed providing criteria for the onset of chaotic behavior.
Focus effects on acoustic cues to sibilant place of articulation
Authors: Chang Yung-hsiang Shawn
Published: June 2017

Prosodically driven contrast enhancement has been reported for vowels and consonantal voicing, but limited evidence of such prosodic strengthening effects has been found for consonantal place of articulation (e.g., Cole et al. 2007, Silbert & de Jong 2008). Chang and Shih (2015) extended similar investigation to the Mandarin alveolar-retroflex contrast. They had participants disambiguate an alveolar or retroflex syllable with phonologically unrelated syllables (e.g., contrasting /sa/ with /bo/) and found no focus enhancement of the alveolar-retroflex contrast. The current study investigated whether employing a smaller contrastive focus domain (i.e., disambiguating contrastive sibilants, such as contrasting /sa/ with /ʂa/) would give rise to sibilant hyperarticulation. Map tasks with stimuli that were vowel context-balanced and lexical frequency-controlled were used for elicitation of focused and unfocused productions of Mandarin alveolars and retroflexes. Results showed that contrastive focus results in adjustments of non-contrastive properties (i.e., longer syllable and frication duration, as well as higher frication amplitude) without enhancing the feature-defining dimension (i.e., a greater acoustic distance between alveolar and retroflex sibilants). Along with evidence from English /s/ and /ʃ/ in Silbert & de Jong (2008), it is suggested that the place contrast of coronal sibilants is less subject to cue-enhancing hyperarticulation.