bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulatory scheme for noise enforcement in New Jersey
Authors: Zwerling Eric M.
Published: October 2013

In the state of New Jersey, noise control programs exist at the state, county, and municipal levels. The Noise Control Act of 1971 (N.J.S.A.13:1G-1, et seq.) is the enabling legislation for the current statewide scheme of noise regulation, which empowered the New Jersey Department of Environmental Protection (DEP) to ‘‘promulgate codes, rules and regulations’’ to control and abate noise. Chapter 29, Noise Control (N.J.A.C. 7:29, et seq.) was adopted in 1974, regulating commercial, industrial, community, and public service facilities. Initially, the DEP conducted field enforcement of the code, but has since delegated the authority primarily to county enforcement programs, pursuant to the County Environmental Health Act (N.J.S.A. 20:3A2-21, et seq.). Local agencies may enforce the state code by agreement with their county or alternatively may adopt the Model Ordinance promulgated by the DEP. The Model Ordinance regulates additional sound sources, including residential, multidwelling and multiuse buildings, and enumerates a list of Restricted Uses and Activities. The state code and Model Ordinance are performance codes which establish specific sound level limits, measured per established protocol. Local jurisdictions lacking the desire or capability of enforcing a performance code may choose to adopt and enforce a more subjective nuisance code.
Impact of low-frequency sound on historic structures
Authors: Sutherland Louis C. , Horonjeff Richard D.
Published: October 2013

In common usage, the term soundscape usually refers to portions of the sound spectrum audible to human observers, and perhaps more broadly other members of the animal kingdom. There is, however, a soundscape regime at the low end of the frequency spectrum (e.g., 10–25 Hz), which is inaudible to humans, where nonindigenous sound energy may cause noise-induced vibrations in structures. Such low frequency components may be of sufficient magnitude to pose damage risk potential to historic structures and cultural resources. Examples include Anasazi cliff and cave dwellings, and pueblo structures of vega type roof construction. Both are susceptible to noise induced vibration from low-frequency sound pressures that excite resonant frequencies in these structures. The initial damage mechanism is usually fatigue cracking. Many mechanisms are subtle, temporally multiphased, and not initially evident to the naked eye. This paper reviews the types of sources posing the greatest potential threat, their low-frequency spectral characteristics, typical structural responses, and the damage risk mechanisms involved. Measured sound and vibration levels, case history studies, and conditions favorable to damage risk are presented. The paper concludes with recommendations for increasing the damage risk knowledge base to better protect these resources.
PARTNER Project 8: Sonic boom mitigation
Authors: Sparrow Victor W.
Published: October 2013

Current U.S. and international laws prohibit commercial supersonic flight over land due to the impact of conventional sonic boom noise. Aircraft manufacturers, however, now have modern computational fluid dynamics and optimization tools, unavailable when those laws were enacted, that will allow them to design and build aircraft with boom signatures that are substantially smoothed compared with traditional N-waves. One purpose of the FAA/NASA/Transport Canada PARTNER Center of Excellence Project 8 is to determine exactly which waveforms would be heard by the public if low-boom supersonic aircraft are put into service. Another purpose is to ascertain the acceptability of those waveforms. The project involves the following universities, government, and industry partners: Penn State, Purdue, Stanford, the National Aeronautics and Space Administration, the Federal Aviation Administration, Boeing, Cessna, Gulfstream, Lockheed-Martin, and Wyle Laboratories. Some of the initial project work includes studies on the propagation of sonic booms through atmospheric turbulence, on the mutual reproducibility of three sonic boom simulators, and on the realism of those simulators as determined by expert listeners. The results of all the studies are intended to provide the FAA with new data to reassess current regulations. [Work supported by NASA, the FAA, and the PARTNER industrial partners.]
Subjective response to low-frequency aircraft noise
Authors: Shapiro Peter J. , Hodgdon Kathleen K. , Atchley Anthony A.
Published: October 2013

The standard metric currently in use by the U.S. government for community noise from aircraft is the day-night level (DNL), which is based on the A-weighting network. However, residents of communities near airports have reported annoyance due to aircraft noise in greater proportion than what the DNL contour associated with their address predicts. Complaints of ‘‘distant rumbling’’ appear to be related to the low-frequency noise that aircraft produce for which the DNL metric does not fully account. This presentation discusses measurements made in October 2004 at two residences near runways at Washington-Dulles International Airport. Noise data are recorded both inside and outside the structures, allowing for a measure of the events’ impact both inside and outside the structure, as well as the filtering effect of the structure on the signal. Laboratory subjective evaluation studies of the recorded aircraft signatures are conducted. Objective metrics, those that are designed for low-frequency noise and those that are not, are calculated and correlated with subjective rankings of the signatures. This gauges the metrics’ effectiveness in predicting subjective perception of aircraft noise signatures. [Work supported by the Federal Aviation Administration and the Exploratory and Foundational Program of the Applied Research Laboratory, Penn State University.]
Forty-five years of open plan office experience: An unusual case study
Authors: Paoletti Dennis A
Published: October 2013

The open plan office design concept has been around for at least 45 years. Through research, design, and practical experience, the basic concepts and parameters that impact acoustics and speech privacy have been fairly well developed and documented. The psychological aspects of human response and expectation to open plan environments, and the conceptual designs that emerge from the architect and interior designers are frontiers that still allow for ongoing study. A large open plan project completed during the dot-com bubble allowed an opportunity to design and experience an unusual open plan environment that utilized exposed sound masking system loudspeakers and minimal sound absorption.
Speech and noise levels for predicting the degree of speech security
Authors: Bradley John S. , Gover Bradford N.
Published: October 2013

A meeting room is speech secure when it is difficult or impossible for an eavesdropper to overhear speech from within. The degree of security could range from less stringent conditions of being barely able to understand a few words from the meeting room, to higher levels, where transmitted speech would be completely inaudible. This paper reports on measurements to determine the statistical distribution of speech levels in meeting rooms and the distribution of ambient noise levels just outside meeting rooms. To select the required transmission characteristics for a meeting room wall, one would first decide on an acceptable level of risk, in terms of the probability of a speech security lapse occurring. This leads to the selection of a combination of a speech level in the meeting room and a noise level nearby that would occur together with this probability. The combination of appropriate estimates of meeting room speech levels and nearby ambient noise levels, together with the sound transmission characteristics of the intervening partition, makes it possible to calculate signal/noise ratio indices related to speech security [J. Acoust. Soc. Am. 116(6), 3480–3490 (2004)]. The value of these indices indicates if adequate speech security will be achieved.
Measuring speech privacy–open plan source speaker evaluation: Part 2
Authors: Good Kenneth , Roy Kenneth
Published: October 2013

Questions regarding differing results from equipment used to measure speech privacy in open plan areas prompted a study to evaluate the importance of the source speaker and its characteristics used in the measurement process. This paper builds on last year’s evaluation of speakers of various performance characteristics. We will look more closely at variations within the spaces measured and reproduction of results.
Diffuse field directivity index measurements of hearing aids operating with adaptive gain algorithms
Authors: Burns Thomas
Published: October 2013

In the summer and autumn of 2004, two hearing aids were used in a round robin study of 3-D directionality as per the test protocol in ANSI S3.35. This protocol required a simulated diffuse field in an anechoic environment by sequentially positioning a loudspeaker along the surface of a 1-m radius sphere circumscribing the device under test. The aids contained both an omni mic and a gradient directional mic, and operational switching between each mic was done with a pushbutton memory. Recently, these aids were brought into Riverbank Labs in Geneva, IL to investigate a different measurement protocol utilizing a simulated diffuse field in a reverberation chamber. The test protocol will be described, and measured results of the 3-D directivity index in this simulated diffuse field will be compared to results from the original round robin study. Finally, this new protocol will be used to measure the 3-D directivity index of hearing aids having an adaptive gain algorithm; these results will be compared to the results of the same adaptive aids as measured with the original ANSI S3.35 protocol even though this protocol specifically requires all adaptive settings to be disengaged.
Verification of the directivity index and other measures of directivity in predicting directional benefit
Authors: Dittberner Andrew , Bentler Ruth
Published: October 2013

The relationship between various directivity measures and subject performance with directional microphone hearing aids was determined. Test devices included first- and second-order directional microphones. Recordings of sentences and noise (Hearing in Noise Test, HINT) were made through each test device in simple, complex, and anisotropic background noise conditions. Twenty-six subjects, with normal hearing, were administered the HINT test recordings, and directional benefit was computed. These measures were correlated to theoretical, free-field, and KEMAR DI values, as well as front-to-back ratios, in situ SNRs, and a newly proposed Db-SNR, wherein a predictive value of the SNR improvement is calculated as a function of the noise source incidence. The different predictive scores showed high correlation to the measured directional benefit scores in the complex (diffuse-like) background noise condition (r=0.89−0.97, p<0.05) but not across all background noise conditions (r=0.45−0.97, p<0.05). The Db-SNR approach and the in situ SNR measures provided excellent prediction of subject performance in all background noise conditions (0.85−0.97, p<0.05) None of the predictive measures could account for the effects of reverberation on the speech signal (r=0.35−0.40, p<0.05).
Methods for hearing aid directivity index measurements under simulated real-ear conditions
Authors: Wagner Randall
Published: October 2013

One technique traditionally used to measure the directivity index of hearing aids involves acquiring data with sound source locations at multiple azimuth angles restricted to the horizontal plane. For measurement of the directivity index of a hearing aid under simulated real-ear conditions, this technique provides limited accuracy due to the inherent asymmetry of the directional response of a manikin-mounted aid. To address this limitation, Working Group 48 of the American National Standards Institute (ANSI) Accredited Standards Committee S3 on Bioacoustics worked on the development of standardized procedures with sound source locations out of the horizontal plane. One procedure given consideration specifies sound source locations on the surface of an icosahedron. The revision of ANSI Standard S3.35 eventually developed by this working group specifies 48 sound source locations on a spherical surface centered about the point on the manikin bisecting the line joining the centers of the ear canals. Details regarding the test setups and procedures used at the National Institute of Standards and Technology to support this development effort will be discussed. Data obtained with the different techniques will also be presented. [Work supported by the Department of Veterans Affairs.]
Acoustics of excited jets—a historical perspective
Authors: Brown Clifford A.
Published: October 2013

The idea that a jet may be excited by an external forcing is not new. The first demonstration of a jet responding to external pressure waves occurred in the late 1800s. It was not, however, until the 1950s, with the advent of commercial jet aircraft, that interest in the subject greatly increased. Researchers first used excited jets to study the structure of the jet and attempt to determine the nature of the noise sources. The jet actuators of the time limited the range (size and Mach number) of jets could be excited. As the actuators improved, more realistic jets could be studied. This has led to a better understanding of how jet excitation may be used not only as a research tool, but also as a method to reduce jet noise.
An overview of flow control for fan noise reduction
Authors: Langford Matthew , Burdisso R. A. , Ng W.
Published: October 2013

The dominant tonal noise source from modern high-bypass-ratio turbofan aircraft engines is due to the impingement of viscous fan rotor wakes onto the downstream stator row. Prior research conducted at NASA Glenn Research Center’s Active Noise Control Fan (ANCF) rig has demonstrated that significant tonal noise attenuation can be achieved by injecting 1.2% to 1.8% of the fan throughflow along a slot in the trailing edge of the rotor. Efforts presented in this paper have focused on reducing the required blowing mass flow while maintaining equivalent noise attenuation levels. Two primary approaches were investigated: blowing in circumferentially non-uniform patterns (i.e., blowing on every other blade), and optimizing the injection scheme itself. The concept of blowing on alternate rotors was experimentally tested in the ANCF rig using NASA’s current slot-blown rotors, and improved attenuation efficiencies were found (although the overall attenuation levels were less). Cascade wind tunnel tests of several different injection schemes were conducted, and the best-performing configuration was incorporated into a new rotor design for experimental validation in the ANCF rig. These rotors achieved similar tonal noise attenuation levels as the slot-blown configuration, but they required injecting less than 0.75% of the fan throughflow.
Deconvolution approach for the mapping of acoustic sources (DAMAS) applied to enhance turbofan engine duct mode measurements
Authors: Dougherty Robert P.
Published: October 2013

Inlet fan noise in turbofan engines is frequently characterized in terms of modal amplitude distribution. The modes can be measured nonintrusively using an array of wall mounted microphones. At high frequency, the number of cuton modes can be much larger than any reasonable number of microphones. This suggests a beamforming analysis technique, rather than a least squares fit, as an appropriate method to extract the mode amplitude from the data. The quality of beamforming output is limited by array resolution and sidelobes. The CLEAN deconvolution algorithm has been used in the past to attempt to improve mode maps from beamforming processing. The recently introduced DAMAS algorithm is a much more comprehensive deconvolution technique, and is well suited to processing mode maps. The benefit of DAMAS is illustrated using simulated mode data. The engine inlet is represented as a cylinder with uniform flow. Two array designs are considered. In each case, several mode distributions are postulated and used to create synthetic array data. Beamforming is applied to create mode maps, and DAMAS is used to deconvolve the array response functions from the mode maps. The results are evaluated by comparing the true mode distributions, the beamform maps, and the deconvolved maps.
Acoustic scatter from a submerged target in a waveguide
Authors: Cuschieri Joseph M. , Charmes Emmanuel , Beaujean Pierre-Phillip
Published: October 2013

In very shallow water or bounded acoustic medium (waveguide), the acoustic scattering from a target located in the waveguide is influenced by the presence of the boundaries. This is due to the multiple reflections occurring between the target and the waveguide boundaries. In this paper, the influence of boundaries on the acoustic scattering from a rigid sphere is investigated. A superposition method with equivalent point sources located inside the surface of the target and calibrated by satisfying the boundary conditions on the surface of the target is used to model the problem. The target is insonified by an equivalent plane acoustic wave traveling parallel to the waveguide boundaries. The presence of the boundaries breaks the symmetry in the scattering patterns and influences the scattering strength of the target. At particular frequencies or scatterer depths, a significant change in the magnitude and spatial distribution of the scattered field occur due to strong coupling between the target and the boundary. It is concluded that the scattering in VSW can be significantly different from that of the same target in an unbounded medium.
Personal computer, printer, and portable equipment noise in classrooms
Authors: Hellweg Robert D. , Dunens Egons K. , Baird Terrance , Olsen John
Published: October 2013

The American National Standard on classroom acoustics (ANSI S12.60-2002) presents criteria for background noise in classrooms. The criteria in ANSI S12.60 do not apply to the noise from portable or permanent built-in equipment used during the course of instruction, such as computers, audiovisual equipment, and printers. ANSI S12.60 provides general guidance on the selection and installation of such equipment; however, the standard does not present specific recommendations for schools to purchase these products to ensure they meet acoustics needs. This paper updates the recommendations made in a NOISE-CON 2003 paper by the authors on an approach for ensuring that computers and instructional material are acceptable acoustically in classroom environments. Schools should use unambiguous purchase specifications based on product A-weighted sound power level criteria. Schools should then install and operate the equipment in a manner to minimize noise emissions—considering both location of products and students and special noise reduction techniques. This paper recommends a purchase specification format; product sound power criteria based on experience and existing environmental criteria; and procedures for installing and locating such equipment in the classroom to minimize noise.
Audibility threshold spectrum for prominent discrete tone analysis
Authors: Kimizuka Ikuo
Published: October 2013

To evaluate the annoyance of tonal components in noise emissions, ANSI S1.13 (for general purposes) and/or ISO 7779/ECMA-74 (dedicatedfor IT equipment) state two similar metrics: tone-to-noise ratio (TNR) and prominence ratio(PR). By these or either of these two parameters, noise of question with a sharp spectral peak is analyzed by high resolution FFF and classified as prominent when it exceeds some criterion curve. According to present procedures, however this designation is dependent on only the spectral shape. To resolve this problem, the author proposes a threshold spectrum of human ear audibility. The spectrum is based on the reference threshold of hearing which is defined in ISO 389-7 and/or ISO 226. With this spectrum, one can objectively define whether the noise peak of question is audible or not, by simple comparison of the peak amplitude of noise emission and the corresponding value of threshold. Applying the threshold, one can avoid overkilling or unnecessary action for noise. Such a peak with absolutely low amplitude is not audible.
Development of noise emission measurement specifications for color printing multifunctional devices
Authors: Kimizuka Ikuo
Published: October 2013

Color printing (including copying) is becoming more popular application in home, as well as in offices. Existing de jule and/or industrial standards (such as ISO 7779, ECMA-74, ANSI S12.10 series, etc.), however, state only monochrome patterns, which are mainly intended for acoustic noise testing of mechanical impact type printers. This paper discusses the key issues and corresponding resolutions for development of color printing patterns for acoustic noise measurements. The results of these technical works will be published by JBMS-74 (new industry standard of JBMIA within 2005), and hopefully be the technical basis of updating other standards mentioned above. This paper also shows the development processes and key features of proposed patterns.
Background noise levels in PC home environments
Authors: Doherty Rina , Salskov Eric , Corriveau Philip J. , Sorenson Paul , Gabel Doug , Beltman Willem M.
Published: October 2013

A study was designed and conducted to determine the background noise levels in the home environment. This is an important factor in determining the acoustic performance of the computing devices that go into these environments. A specialized methodology was developed and measurements were carried out in homes in the United States, Sweden, Germany, and China. The sound levels in three rooms in 15–18 homes in each country were collected over 24-h periods. The results indicated that the background noise levels ranged between 30 and 40 dBA across the four countries. Variations in the background noise levels between the different rooms in the homes were minimal. No significant variations were found between home types (detached, semi-detached, and apartment) and community types (urban, suburban). However, European homes were quieter than United States and Chinese homes. The variations between countries were statistically significant. In addition to the background noise levels, the acoustical characteristics of the rooms were measured. The results indicated that the reverberation radius was typically below 1 m and was fairly consistent between geographies.
Effect of lining anisotropy on sound attenuation in lined ducts
Authors: Kim Jeong-Woo , Bolton J. Stuart , Alexander Jonathan H.
Published: October 2013

In this paper, the effect of duct-lining anisotropy, with respect to flow resistivity, in particular, is considered. The duct lining is modeled by using a fully poroelastic theory derived from the Biot theory. The lining is considered to occupy only a part of the duct cross section, and is imagined to be infinite in length. When the appropriate solutions for the sound fields within the airway and the anisotropic porous material are substituted into the boundary conditions of the problem, a homogeneous system of equations results. The propagation characteristics of the duct modes can then be found by identifying the conditions under which the determinant of that system of equations is zero. Corresponding experiments have been conducted using samples of aviation-grade glass fiber partially lining a square-section, four-microphone standing wave tube. Excellent agreement between measured attenuations and predictions was found. It will be shown that the modal attenuation is primarily sensitive to the flow resistivity of the lining in the axial direction.
Wave based optimization of distributed vibration absorbers
Authors: Johnson Marty , Batton Brad
Published: October 2013

The concept of distributed vibration absorbers or DVAs has been investigated in recent years as a method of vibration control and sound radiation control for large flexible structures. These devices are comprised of a distributed compliant layer with a distributed mass layer. When such a device is placed onto a structure it forms a sandwich panel configuration with a very soft core. With this configuration the main effect of the DVA is to create forces normal to the surface of the structure and can be used at low frequencies to either add damping, where constrain layer damper treatments are not very effective, or to pin the structure over a narrow frequency bandwidth (i.e., large input impedance/vibration absorber approach). This paper analyses the behavior of these devices using a wave based approach and finds an optimal damping level for the control of broadband disturbances in panels. The optimal design is calculated by solving the differential equations for waves propagating in coupled plates. It is shown that the optimal damping calculated using the infinite case acts as a good ‘‘rule of thumb’’ for designing DVAs to control the vibration of finite panels. This is bourn out in both numerical simulations and experiments.
An environmental and economical solution to sound absorption using straw
Authors: McGinnes Courtney , Kleiner Mendel , Xiang Ning
Published: October 2013

The growing attentiveness to using environmentally friendly materials in the building construction industry as a whole has led many architects to research the use of natural materials. Natural fibers, such as straw, are advantageous due to their accessibility, ease of processing, and their ability to be discarded with a lesser environmental impact through biodegradability. While the material focus may have shifted, the need for quality acoustic environments has remained the same. In a set of preliminary studies, the absorption coefficients of sound absorbers using natural fibers have been proven to have comparable values relative to other highly absorptive, nonenvironmentally friendly materials such as mineral wool and fiberglass. The absorption coefficients were evaluated for octave and third-octave frequencies (125 to 4000 Hz) using the impedance tube method with one microphone. While these absorbers may be acoustically effective as well as environmentally friendly, there may be potential concerns in using natural fibers such as their life span, fire rating, and potential health risks, i.e., disposal techniques, allergenic reactions, and insect and fungus infestation.
Rating of sound insulation associated to different climates in Spain. Dwellings located in Mediterranean subtropical climate
Authors: Meza Marín Leonardo , Recuero Loṕez Manuel
Published: October 2013

The purpose of this paper is to correlate the sound insulation of dwellings with its location in different climatic zones existent in Spain. Dwellings situated in a region with Mediterranean subtropical climate were analyzed in this stage. Fifty dwellings situated in Malaga, south of Spain (36 43N, 4 25W) were selected. These dwellings are representative of the type of construction used in this area. To characterize the airborne conduction of noise, 150 measurements of airborne sound insulation of facade were carried out, following ISO 140-5 standard. In living rooms and bedrooms, R45w was obtained, following ISO 717-1 standard. Finally, a correlation was found between the apparent sound insulation and the different type of construction of the different type of facade.
Assessment of technologies for predicting insertion loss and directivity of power plant exhaust systems
Authors: Cummins Jim R. , Loewenstein Marshall
Published: October 2013

Much technology exists for predicting the insertion loss, directivity and radiation of various components in a power plant. For example, the ASHRAE noise guide gives the IL and/or directivity for many duct configurations. Unfortunately, there are also many components or geometries for which there is currently no practical prediction methodology. The state of the technology for predicting insertion loss, directivity and sound radiation by power plant components, especially ducted sources, such as intake and exhaust, is reviewed with emphasis on modeling techniques and verification. Several cases where the normal prediction methods are both adequate and inadequate are presented. Suggestions are given as to methods and/or future development that could provide more accurate, reliable, or useable results.
New security and privacy laws require basic changes in professional practice
Authors: Sykes David M.
Published: October 2013

Everybody knows about HIPAA—but what about GLBA? FIPA? The Patriot Act? Homeland Security? NCLB? FCRA? CASB1? PIPEDA? All of these are recent laws that impact acoustical design. Throw in the American Hospital Association/ASHE and AIA’s about-to-be-released ‘‘Guidelines for the Design of Healthcare Facilities’’ as well as the redrafting of DCID 6/9 and it looks like time for careful examination of some professional practices relating to security and privacy. Should INCE members join with and endorse the ASA’s recently formed Joint TCAA/TCN Subcommittee which aims to fill a policy vacuum in Washington and Ottawa relating to the fundamental protection of citizens’ rights to privacy? This group will formulate consistent guidelines to enable federal and state agencies in the US and Canada to enforce and monitor their laws—will their guidelines affect INCE members? Those who advise or give expert testimony to government agencies, defense/security organizations, courts, and large institutions in financial services, healthcare or education likely find themselves in a rapidly shifting landscape and recognize the need to respond with new research and professional practices.
Acoustical and noise redesign considerations when trying to increase patient privacy while ensuring comfort
Authors: Klavetter Eric
Published: October 2013

An internal assessment was undertaken to understand the flow of patients to ensure comfort and privacy during their health care experience at Mayo Clinic. A number of different prototypes, work flows, and methodologies were utilized and assessed to determine the ‘‘best experience for our patients.’’ A number of prototypes ranging from self-check in to personal pagers were assessed along with creating environments that introduced ‘‘passive distractions’’ for acoustical and noise management, which can range from fireplaces, to coffee shops to playgrounds to ‘‘tech corridors.’’ While a number of these designs are currently being piloted, the over-reaching goal is to make the patient experience ‘‘like no other’’ when receiving their care at Mayo Clinic.
Acoustical renovation of temporary classrooms to meet American National Standards Institute (ANSI) standard
Authors: Lubman David
Published: October 2013

This exercise demonstrates that key requirements of the ANSI S12.60-2002 on classroom acoustics can be met through renovations at modest cost. Free-standing classrooms at two schools in Southern California were successfully renovated. Noise levels were greatly reduced, and now meet requirements of the ANSI standard. A 1950s style bungalow classroom at the Paradise Canyon School (PCS) in Los Angeles County and a double-trailer classroom at the Wildomar Elementary School (WES) in Riverside County were targeted. The aim was to make classrooms suitable for pupils with severe hearing disabilities. But the methods used apply equally to mainstream classrooms. At both schools the above-ceiling air distribution systems were modified to produce quiet airflow. At PCS, a noisy rooftop heat pump was replaced with a much quieter rooftop heat pump and installation. At WES, a noisy wall-mounted heat pump was replaced with a new unit mounted on an exterior concrete pad. At PCS, exterior noise intrusion was achieved by replacing a poorly performing accordion wall with a permanent wall. Further noise reduction can be achieved by replacing leaky windows. Exterior noise intrusion at WES was obtained by replacing leaky windows. The resulting acoustical improvements are documented. Costs and lessons learned are discussed.
Numerical simulation of jet noise from different jet nozzle geometries
Authors: Paliath Umesh , Morris Philip J.
Published: October 2013

This paper describes the numerical simulation of flow-induced noise from jets with different nozzle geometries. The nozzles considered include axisymmetric and nonaxisymmetric nozzles, such as circular and rectangular. Also the study is extended to examine the differences between noise radiated from nozzles with planar exists and those with nonplanar exist, such as beveled nozzles. The detached-eddy simulation (DES) approach is used to simulate both the jet nozzle internal and external flows as well as the jet plume. This methodology allows the turbulence model to transition from an unsteady Reynolds averaged Navier-Stokes (URANS) method for attached boundary layers to a large-eddy simulation (LES) in separated regions. Thus, it is ideally suited to jet flow simulations when the nozzle is included. Both cylindrical polar and Cartesian coordinate systems are used as the basis for grid generation. The one equation Spalart-Allmaras turbulence model is used to describe the evo! lution of the turbulent eddy viscosity. Dispersion relation preserving algorithms are used for spatial discretization and an explicit 4th order Runge-Kutta scheme is used for time marching. The far-field sound is evaluated using the Ffowcs Williams-Hawkings permeable surface acoustic analogy. This permits the noise to be predicted at large distances from the jet based on fluctuations in the jet’s near field. This provides a good compromise between numerical accuracy and computational cost. The results are compared with experimental data for both unheated and heated jet cases.
Biases introduced by the fitting of functions to attitudinal survey data
Authors: Schomer Paul D.
Published: October 2013

For years researchers have toiled to understand community response to noise environments such as the environment around airports, near highways, or near railroads. Frequently, following the lead of Schultz and others, researchers have attempted to develop a ‘‘dose-response’’ relationship by fitting curves through aggregated data that report some measure of community response versus some measure of the noise environment. For example, in 1992 FICON, a U.S. Government interagency group, reviewed the then available totality of attitudinal survey data and developed a functional fit to those data. This paper examines the fit used and shows that the assumptions employed by FICON lead to a systematic under-estimation of the percent highly annoyed in the critical 55 to 75 DNL region. In fact, they underestimated the true percentage highly annoyed by a factor of more than 4 times. FICON predicts 6 percent ‘‘highly annoyed’’ at 60 DNL when the true value is 27 percent.
Generation and processing of finite-amplitude ultrasonic signals in the context of nonlinear (harmonic) medical imaging
Authors: Wallace Kirk D. , Krueger Todd M. , Lloyd Christopher W. , Holland Mark R. , Miller James G.
Published: October 2013

The focus of this talk is on the application of finite-amplitude ultrasonic waves in the context of diagnostic imaging. Techniques based on nonlinearly generated harmonic signals (tissue harmonic imaging) have rapidly supplanted linear (fundamental) imaging methods as the standard in two-dimensional echocardiography. Improvements in image quality achieved through the use of nonlinear imaging modes have served as the prime motivating factor that continues to drive this revolution. For many patients, the resulting harmonic images are widely recognized as being of apparently higher quality, and less corrupted by artifacts, than the corresponding fundamental images. The benefits associated with nonlinear imaging have been attributed to a number of potential factors, including reduced sensitivity to phase and amplitude aberration, enhanced beam compactness (narrower mainlobe and reduced sidelobe levels), higher imaging frequencies while suffering only a portion of the corresponding attenuation penalty, and reduced interference from reverberations and off-axis echoes. Although much of the physics describing the nonlinear propagation and distortion of finite-amplitude ultrasonic waves is well understood, there remain many unanswered questions about the details of the physics and rank ordering of the factors underlying the improvements associated with nonlinear (harmonic) imaging.
Diagnostic imaging in biomedical ultrasound
Authors: Everbach E. Carr
Published: October 2013

Since World War II, ultrasonic imaging has evolved from its sonar origins to include techniques borrowed from MRI, image processing, and computer modeling. Although diagnostic ultrasound techniques make increasing use of second-order physics such as tissue nonlinearity, much potentially useful information remains unexploited. In addition, safety and health concerns must be balanced against clinical usefulness. The tutorial will review the fundamental concepts and practices of diagnostic ultrasound imaging, and describe current research efforts underway to extend this modality into new areas.
Cyril Harris: A biographical sketch
Authors: Kuhl Patricia
Published: October 2013

For over half a Century, Cyril Harris has authored numerous scholarly books and papers and designed concert halls that enhance our enjoyment of the arts. In recognition of these accomplishments, Cyril has been honored with medals and awards that pay tribute to his professional talents, including, but not limited to, the highest awards of the Acoustical Society of America. In this talk, I will attempt to shed some light on Cyril’s personal history, the paths that led him to a distinguished career in acoustics, and the people and events that provided inspiration during Cyril’s long and highly successful career.
Acoustical design in architecture
Authors: Garrett Steven
Published: October 2013

Cyril Harris’s name is best known to the general public for the outstanding concert halls he has designed. But his impact on reduction of noise and vibration through the application of established fundamental engineering design principles is far greater through the work of others who have benefited from the books (and particularly handbooks) he has written and edited. His first book, co-authored with Vern Knudsen, Acoustical Design in Architecture, was published over a half-century ago. It was the first milestone on a continuing quest to explain the physics and engineering of acoustics, as well as noise and vibration control, to those who are responsible for the design of habitable structures. [See the excellent review in J. Acoust. Soc. Am. 22, 521 (1950).] To expand the utility of this approach, Professor Harris assembled and regularly revised two comprehensive compilations: the Shock and Vibration Handbook (now in its fourth edition) and the Handbook of Acoustical Measurements and Noise Control (now in its third edition and available from ASA). Those handbooks make the application and the evaluation of required techniques accessible to the entire community of noise control engineers and architects. The presentation will also briefly describe his books on architecture and architectural history.
Cyril Harris and shock and vibration engineering
Authors: Piersol Allan G.
Published: October 2013

Cyril Harris is well known as an internationally recognized authority in the field of architectural acoustics. However, some may not be aware of the fact that Cyril Harris has also been for many years a leading authority in shock and vibration engineering. He became particularly prominent in this area in 1961 with the publication by McGraw-Hill of the ‘‘Shock and Vibration Handbook,’’ which was originally coedited by Cyril Harris and Charles Crede. That Handbook is now in its fifth edition with Harris’ name in the title and Allan Piersol as the coeditor. The purpose of this presentation is to summarize the importance of that Handbook to shock and vibration engineering for the past 44 years, as well as the experience of working with Cyril Harris on the preparation of the fifth edition.
Vocally mediated social recognition in anurans
Authors: Bee Mark A.
Published: October 2013

Anuran amphibians (frogs and toads) are among the most vocal of vertebrates and have long served as model systems for investigating the mechanisms and evolution of acoustic communication. Compared to higher vertebrates, however, the role of cognition in anuran communication has received less attention, at least in part due to the lack of evidence that juvenile anurans learn to produce signals or associate them with particular social contexts. Recent studies of social recognition in two anuran families indicate that territorial male frogs in some species are able to learn about and recognize the individually distinctive properties of the calls of nearby neighbors. For example, male bullfrogs (ranidae) learn about the pitch of a neighbor’s vocalizations (an individually distinct voice property) and associate a familiar pitch with the location of the neighbor’s territory. As in songbirds, this form of vocally mediated social recognition allows territory holders to direct low levels of aggression toward well-established neighbors, while maintaining a readiness to respond aggressively to more threatening strangers that may attempt a territory takeover. A brief review of currently available data will be used to illustrate how anurans can serve as model systems for investigating the role of cognition in acoustic communication.
Vocal behavior and risk assessment in wild chimpanzees
Authors: Wilson Michael L. , Hauser Marc D. , Wrangham Richard W.
Published: October 2013

If, as theory predicts, animal communication is designed to manipulate the behavior of others to personal advantage, then there will be certain contexts in which vocal behavior is profitable and other cases where silence is favored. Studies conducted in Kibale National Park, Uganda investigated whether chimpanzees modified their vocal behavior according to different levels of risk from intergroup aggression, including relative numerical strength and location in range. Playback experiments tested numerical assessment, and observations of chimpanzees throughout their range tested whether they called less frequently to avoid detection in border areas. Chimpanzees were more likely to call to playback of a stranger’s call if they greatly outnumbered the stranger. Chimpanzees tended to reduce calling in border areas, but not in all locations. Chimpanzees most consistently remained silent when raiding crops: they almost never gave loud pant-hoot calls when raiding banana plantations outside the park, even though they normally give many pant-hoots on arrival at high-quality food resources. These findings indicate that chimpanzees have the capacity to reduce loud call production when appropriate, but that additional factors, such as advertising territory ownership, contribute to the costs and benefits of calling in border zones.
Classification of communication signals of the little brown bat
Authors: Melendez Karla V. , Jones Douglas L. , Feng Albert S.
Published: October 2013

Little brown bats, Myotis lucifugus, are known for their ability to echolocate and utilize their echolocation system to navigate, locate, and identify prey. Their echolocation signals have been characterized in detail, but their communication signals are poorly understood despite their widespread use during the social interactions. The goal of this study was to characterize the communication signals of little brown bats. Sound recordings were made overnight on five individual bats (housed separately from a large group of captive bats) for 7 nights, using a Pettersson ultrasound detector D240x bat detector and Nagra ARES-BB digital recorder. The spectral and temporal characteristics of recorded sounds were first analyzed using BatSound software from Pettersson. Sounds were first classified by visual observation of calls’ temporal pattern and spectral composition, and later using an automatic classification scheme based on multivariate statistical parameters in Matlab. Human- and machine-based analysis revealed five discrete classes of bat’s communication signals: downward frequency-modulated calls, constant frequency calls, broadband noise bursts, broadband chirps, and broadband click trains. Future studies will focus on analysis of calls’ spectrotemporal modulations to discriminate any subclasses that may exist. [Research supported by Grant R01-DC-04998 from the National Institute for Deafness and Communication Disorders.]
Modeling neural adaptation in the frog auditory system
Authors: Wotton Janine , McArthur Kimberly , Bohara Amit , Ferragamo Michael , Megela Simmons Andrea
Published: October 2013

Extracellular recordings from the auditory midbrain, Torus semicircularis, of the leopard frog reveal a wide diversity of tuning patterns. Some cells seem to be well suited for time-based coding of signal envelope, and others for rate-based coding of signal frequency. Adaptation for ongoing stimuli plays a significant role in shaping the frequency-dependent response rate at different levels of the frog auditory system. Anuran auditory-nerve fibers are unusual in that they reveal frequency-dependent adaptation [A. L. Megela, J. Acoust. Soc. Am. 75, 1155–1162 (1984)], and therefore provide rate-based input. In order to examine the influence of these peripheral inputs on central responses, three layers of auditory neurons were modeled to examine short-term neural adaptation to pure tones and complex signals. The response of each neuron was simulated with a leaky integrate and fire model, and adaptation was implemented by means of an increasing threshold. Auditory-nerve fibers, dorsal medullary nucleus neurons, and toral cells were simulated and connected in three ascending layers. Modifying the adaptation properties of the peripheral fibers dramatically alters the response at the midbrain. [Work supported by NOHR to M.J.F.; Gustavus Presidential Scholarship to K.McA.; NIH DC05257 to A.M.S.]
Reducing traffic noise with quieter pavements
Authors: Donavan Paul
Published: October 2013

In recent years, interest has increased in the use of pavement type to reduce traffic noise. This has been driven by public concern over noise from freeways and state transportation agencies’ interest in using pavement instead of sound walls to mitigate traffic noise. Beginnings of the recent interest go back to 1998 with the formation of the Institute for Safe, Quiet & Durable Highways at Purdue University and the initiation long-term research by the California Department of Transportation (Caltrans) on the effectiveness of quieter pavements. In 2002, the State of Arizona announced plans to overlay 115 miles of concrete freeway in the greater Phoenix area with a quieter asphalt rubber surface. This turned into the first Quiet Pavement Pilot Program in partnership between Federal Highway Administration (FHWA) and the Arizona Department of Transportation. Since that time, the FHWA in cooperation with the American Association of State Highway Transportation Agencies conducted a fact finding ‘‘Scan’’ tour in Europe to evaluate their quiet pavement technology and policy. This was followed by the first comparative tire/pavement noise testing in the US and Europe using the same procedures and test tires. The results, issues, and future directions surrounding these activities will be discussed.