bluuebunny/crossref_metadata_2025 huggingface dataset:
The analysis of the environmental influence of drilling installation
Authors: Wszolek Wieslaw , Macuda Jan , Wszolek Tadeusz
Published: July 2012

Drilling work, due to its character, settlement, and whole-day service, has potential acoustic danger for the environment. The degree of influence depends on many factors, e.g., the type of drilling equipment, applied acoustic screens, localization of drilling and its surroundings, the type of drilled-trough rocks, and applied drilling technology. The main sources of acoustic noise are motors, pumps, and current generators. The distinction can be made between some procedures that are more noisy than the normal drilling process, for example, tripping. Usually the drilling rig is poorly equipped with noise reduction installation. Experiments were carried out on eight types of drilling assemblies. The received results show that different drilling equipment has an individual influence on the environment. The evident proof of that is the azimuthal acoustic characteristic and additionally the noise level dependence from the cycle of drilling work. The level of LAeq in the surroundings of the examined drilling rig has been made. It has been proved that, due to the noise reduction, the selection of optimal settlement of the drilling rig and optional equipment is possible. In this optimalization process, the cycle of drilling work has been considered. This reduction is possible without additional acoustic protection.
Rotorcraft noise model (RNM) and acoustic repropagation technique (ART2) validation and application using CH-146 (Bell 412) measurement data
Authors: Page Juliet A. , Downing J. Micah
Published: July 2012

A series of acoustic measurements were conducted at Moose Jaw Canadian Forces Base, Saskatchewan, Canada in June, 1998 for obtaining detailed noise data on a large array of ground- and crane-based microphones for a CH-146 helicopter. The project, conducted by the North Atlantic Treaty Organization (NATO) Committee on the Challenges of Modern Society was to define test procedures and analysis methods for the standardization of a NATO rotorcraft noise database. Four independent microphone arrays were deployed by the USAF, NASA, RAF, and DERA. Data from the USAF and NASA arrays were used to validate the Rotorcraft Noise Model (RNM). USAF data were processed via an updated acoustic repropagation technique (ART2) to define the rotorcraft broadband sound hemispheres. The source noise was then propagated to the measurement locations using RNM. Agreement with the original USAF measurements demonstrated consistency of the ART/RNM process. Agreement with the independent NASA measurements provided validation of the RNM as a prediction tool.
Field measurements of a reduced-scale noise barrier’s insertion loss and absorption coefficients
Authors: Busch Todd A. , Nugent Ramon E.
Published: July 2012

In situ testing determined the insertion loss (IL) and absorption coefficients of a candidate absorptive barrier material as part of a project to abate railway noise in Anaheim, California. A 13000-ft barrier is proposed south of the tracks, but residents of Yorba Linda to the north have had concerns that barrier reflections will increase their noise exposure. To address this issue, a 12-ft-high by 48-ft-long demonstration barrier was built in the parking lot of Edison Field, Anaheim, as part of a public open hours, thereby allowing for acoustical measurements. The barrier’s insertion loss (IL) was measured in one-third-octave bands assuming 1/2-scale construction. The IL for three (scaled) railway noise sub-sources (rail/wheel interface, locomotive, and train horn) was measured at six (scaled) distances. The highest total A-weighted IL, after corrections for finite barrier and point-source speaker effects, was 22 dB(A) for rail/wheel noise and 18 dB(A) for locomotive noise. Absorption coefficients were measured using a time-delay spectrometry technique, and were found to be much less than the reverberation room results advertised in the manufacturer’s literature, though the resulting increase for noise exposure to Yorba Linda residents is still expected to be less than 1 dB(A).
Random and periodic square wave barriers in noise control
Authors: Sarigul-Klijn Nesrin , Karnopp Dean
Published: July 2012

Federal regulations and increased public interest in reducing transportation noise have led to the construction of miles of sound walls. Most of these walls are almost perfectly non-absorptive barriers with the shortest possible diffractive edge; a straight line. A number of alternate strategies have been studied in recent years, including T-top, Y-top and random edged barriers.Prior investigations by other researchers suggest that it might be possible to improve the performace of a barrier without increasing the average height by introducing a jagged profile. This is because the jagged geometry on the edge of a sound wall alters the sound pressure level in the shadow zone by causing the region of the barrier nearest the receiver to admit multiple paths with variable phase. The direct waves from the diffracting edges of the barrier and waves subsequently reflected from the ground plane are superposed at the receiver causing constructive or destructive interference at the receiver. This is not easily amenable to analytical methods. This led to anechoic chamber testing of the various practical jagged edge treatments. In this paper, theoretical and experimental investigation of the effectiveness of more practical random and square wave barriers are detailed. The TNCC Anechoic chamber experimental facility is utilized for one-sixth scaled barrier tests.
Active control of structurally radiated sound
Authors: Hong Jin Seok , Kim Heung Seob , Shin Kihong , Oh Jae-Eung
Published: July 2012

In this paper, active control of radiating sound (using active structural acoustic control) from a vibrating rectangular plate by a steady-state harmonic point force disturbance is experimentally studied. Two piezoceramic actuators are bonded directly to the panel surface to provide control input structure. The sensor consists of two accelerometers mounted on the plate. Estimated radiated sound signals using a vibro-acoustic path transfer function are used as error signals. The vibro-acoustic path transfer function represents a system between accelerometers and microphones. The controller is a 2 by 2 filtered-x LMS algorithm implemented on a TMS320C30 DSP. The results demonstrate good control of sound radiation using the vibro-acoustic path transfer function.
Segment realization in relation to a carrier word’s uniqueness point
Authors: Billerey-Mosier Roger
Published: July 2012

This paper determines whether the acoustic realization of English phones differs depending on their position relative to a carrier word’s uniqueness point, defined as the earliest point at which that word differs from all the words in the lexicon that share the same initial string. As words are confidently identified at their uniqueness point [Marslen–Wilson (1987)], phonetic material past that point may play a less crucial disambiguating role and show signs of reduction akin to those reported in Wright (1997), who found that vowels in monosyllabic words with relatively few perceptual neighbors are acoustically reduced. The acoustic duration of segments located at and past a carrier word’s uniqueness point is compared (e.g., -erry in blueberry and strawberry, respectively, because of blueberry’s competitors bluebird, blueblood, etc.). No consistent pattern of differences is found. This result suggests that the domain of Lindblom’s (1990) hypospeech and hyperspeech model is higher than the word. The implications of this result for DeJong’s (1995) characterization of stress in English as word-level hyperarticulation are discussed.
Distinctive functional load of pitch-accent in Japanese based on word familiarity
Authors: Kitahara Mafuyu , Amano Shigeaki
Published: July 2012

The present paper proposes to measure the ‘‘functional load of pitch-accent’’ for Japanese words. It is calculated from (1) the ratio of the number of accentually contrastive homophone pairs to the number of noncontrastive pairs; and (2) the difference between word-familiarity ratings for each pair. The functional load is larger when there are more contrastive homophones to noncontrastive homophones for the target word, and when the difference of word familiarity scores is smaller between each homophone pair. A large scale word-familiarity database is used for the calculation of functional load and other statistical properties of pitch accent. Distribution of accent and opposition types at each word length are investigated with respect to familiarity scores. Results show that oppositions which include an unaccented form dominate in short simplex words, from low to high-familiarity range. This suggests that the role of pitch accent in distinguishing homophones is biased to the presence–absence contrast, and not to the location per se of pitch accent. Preliminary results from a perception experiment suggest that top-down information in the lexicon, such as functional load and distribution of accent and opposition types, interacts with the bottom-up process in lexical access.
Coarticulatory information in natural speech stimuli is crucial for infant recognition of syllable sequences
Authors: Curtin Suzanne , Mintz Toben , Byrd Dani
Published: July 2012

Recent research has determined that coarticulatory information in speech provides important cues to early word segmentation. This experiment investigates whether 7-month-old infants’ ability to recognize a string requires the presence of appropriate coarticulatory information in the speech familiarization stream. Following familiarization to a string of CV syllables, infants were tested to determine if sequences that co-occurred in the familiarization string were preferred over those in which the syllables did not appear adjacently during familiarization. Further, the test phase was conducted so that the items had either appropriate or inappropriate coarticulation information. The results indicate that infants tested on items with appropriate coarticulation listened significantly longer to strings that had appeared during familiarization than to the appropriately coarticulated control strings that never occurred together during familiarization. Interestingly, when presented with inappropriate coarticulation test items, infants showed no preference for previously familiarized strings over the non-co-occurring syllable strings. We conclude that infants are sensitive to coarticulation in recognizing sequences in a speech stream. Furthermore, coarticulatory cues, in combination with other cues to segmentation, greatly enhance recognition of syllable sequences. These results suggest that coarticulation plays an important role in early word segmentation. [Work supported by NIH Grants DC-03172 and SSHRC 752-98-0283.]
Visual influences on internal structure of phonetic categories
Authors: Brancazio Lawrence , Miller Joanne L. , Paré Matthew A.
Published: July 2012

We investigated effects of visual place of articulation on internal category structure for voiceless consonants. Volaitis and Miller [J. Acoust. Soc. Am. 92, 723–735 (1992)], measuring category goodness for tokens from extended auditory voice-onset-time (VOT) /bi/-/pi/-*/pi/ and /gi/- /ki/-*/ki/ continua, found that the best exemplars of /ki/ fell at longer VOTs than those of /pi/, consistent with the well-known difference between /b/-/p/ and /g/-/k/ voicing boundaries. To explore the basis of this best-exemplar shift, we changed perceived place of articulation of auditory stimuli by pairing them with an incongruent visual token (i.e., the McGurk effect). First, we established that the best-exemplar region for /t/ (like /k/) falls at longer VOTs than that for /p/ for auditory bilabial and alveolar continua. Second, subjects rated auditory /bi/-/pi/-*/pi/ stimuli with visual /pi/ (congruent) and /ti/ (incongruent) tokens as exemplars of /pi/ or /ti/, respectively. The best-exemplar region fell at longer VOTs for /ti/ than /pi/, consistent with previously reported visually induced voicing boundary shifts [Green and Kuhl, Percept. Psychophys. 45, 34–42 (1989); Brancazio et al., J. Acoust. Soc. Am. 106, 2270 (1999)]. Thus, perceived place of articulation influences internal category structure even when auditory properties are unchanged, suggesting that the structure is not strictly governed by psychoacoustic factors. [Work supported by NIH/NIDCD.]
Time-varying information for vowel identification in visual speech perception
Authors: Yakel Deborah A. , Rosenblum Lawrence D.
Published: July 2012

The relative salience of time-independent and time-varying dimensions during vowel identification accuracy was examined for visual speech perception. Six different conditions were created using nine vowels /o,I,i,e,ae,a,u,U,uh/ in the consonantal context /bVb/: control syllables, variable center syllables, silent center syllables, initial syllables, and final syllables. Control syllables were full syllables. Variable center syllables were produced by deleting the beginning and end transitions, leaving 50%–60% of the vowel. In silent center syllables, 50%–60% of the vowel was removed, leaving the beginning and end transitions. Initial syllables contained the beginning transition, and final syllables contained the end transition. Results revealed that silent center vowels were identified as accurately as the control syllables. All other conditions showed a significant decrease in visual vowel identification accuracy. A follow-up experiment revealed that the silent center syllable accuracy was greater than the variable center syllables even when their durations were similar. These results are analogous to findings in auditory speech perception [J. J. Jenkins, W. Strange, and T. R. Edman, Percept. Psychophys. 33, 441–450 (1983)] and suggest that the time-varying aspects of the syllable may be the primary source of information for visual vowel identification.
Bistatic target detection, interferometry, and imaging with an autonomous underwater vehicle platform
Authors: Edwards Joseph R. , Schmidt Henrik , LePage Kevin D.
Published: July 2012

The acoustic detection and classification of completely and partially buried objects in the multipath environment of the coastal ocean presents a major challenge to the underwater acoustics community. However, the rapidly emerging autonomous underwater vehicle (AUV) technology provides the opportunity of exploring entirely new sonar concepts based on mono-, bi-, or multistatic configurations. For example, the medium frequency regime (1–10 kHz) with its bottom penetration advantage may be explored using large synthetic apertures, where acoustic information is accumulated over a series of sonar pings. The performance of such approaches is highly dependent on accurate platform navigation and timing, which poses a significant challenge to AUV developers, particularly because the navigation procedures are themselves dependent on the complicated multipath acoustic environment. Using experimental data from the GOATS’98 SACLANTCEN/MIT experiment, this paper describes an investigation into the feasibility of combining seabed scattering data from consecutive pings of a fixed parametric source to form a bistatic synthetic aperture for target localization and imaging with an AUV-based receiving platform. The paper describes different levels of bistatic processing including both incoherent and coherent beamforming and very large aperture interferometric approaches, and the associated performance trade-offs are discussed. [Work supported by ONR and SACLANT.]
Integration of numerical scattering functions with the ocean wave-guide
Authors: Lim Chee K. , Goh J. T.
Published: July 2012

Based on the generalized modal formulation of acoustic scattering by F. Ingenito [J. Acoust. Soc. Am. 82, 2051–2059 (1987)] in a stratified ocean, we present a method for integrating a numerical scattering function obtained from a commercial boundary element code, sysnoise, with an acoustic propagation code to study scattering from arbitrary objects. We benchmarked the hybrid method by comparing the scattered fields for a rigid spherical shell obtained using this approach with an analytical solution. We discuss issues related to the numerical implementation of the approach, such as the extraction of the scattering function for an unbounded ocean medium, correct extraction of multiple modal scattering kernal using a single scattering function (for axis-symmetrical object) and numerical phase compensation procedures associated with numerical source location. The methodology developed here would allow the study of acoustic scattering problems in the ocean for arbitrary-shaped elastic objects, which are not amenable to analytical means but solvable only by numerical methods.
Comparison of the shallow water acoustic scattering from a submarine-shaped object with that from canonical shapes
Authors: Lim Chee K.
Published: July 2012

The scattering from an arbitrary-shaped object like a submarine is a complex process. In practice, for detection studies, canonical shapes such as a cylinder have been widely used to emulate a submarine-shaped object. However, the validity of this approximation is not easily quantified. In a previous paper [Chee K. Lim, ‘‘Integration of numerical scattering functions with the ocean wave-guide,’’ 139th ASA, Nov. 2000], the approach to integrating scattering functions computed using commercial codes with a propagation code was presented. The approach allows convenient calculation of scattering from very complex elastic objects. This presentation will compare the acoustic scattered field of eight different targets—a rigid sphere, rigid cylinder, rigid cone, rigid submarine-shaped object, elastic cylinder, stiffened elastic cylinder, stiffened elastic cone and, lastly, a stiffened elastic submarine-shaped object. Five aspects source angles (0, 45, 90, 135 and 180 deg) and their corresponding forward- and backward-scattered field will be compared using the results of the submarine-shaped object as the reference solution. The results would provide useful insights for future underwater acoustic scattering modeling and model-based signal processing.
Scattering of acoustic waves by a prolate body in plane-stratified waveguide
Authors: Katsnelson Boris G. , Grigoryev Valery A. , Kuzkin Venedict M. , Petnikov Valery G.
Published: July 2012

Technique for calculation of diffraction field by spatially localized inhomogeneity is proposed. This technique is based on the fact that the scattering matrix of the waveguide mode is expressed through the scattering amplitude in free space. This permits separation of the diffraction problem in free space and the propagation problem in the waveguide (the problem of calculation of waveguide modes). Requirements for sound-speed variation and for distance between scatterer and waveguide boundaries are formulated. On the basis of the energetic approach, the concept of the cross section in the waveguide is proposed. The coupling modes and sound absorption are discussed as well. The space-time structure of a sound field scattered by the moving localized inhomogeneity in the direction of incident wave (the forward scattering) is given and discussed. As an example, structure of the sound field for a scatterer modeled by spheroid prolate for different parameters of waveguides is calculated. [Work supported by RFBR, Grant 99-02-17671.]
Herring hydroglyphics in littoral waters of the northern Gulf of Mexico
Authors: Nero Redwood W. , Thompson Charles H. , Dubberley John R. , Love Richard H.
Published: July 2012

A large shoal of fish occurring in the vicinity of the 220-m isobath was observed using a standard 38-kHz fisheries echosounder and a 1.5- to 10-kHz low-frequency fish sonar (LFFS) for several days in July 2000. The fish behaved like herring, exhibiting a rapid rise to the sea surface at dawn, formation into schools, and a rapid descent to the sea floor. Schools remained at depth through the day and gradually rose to the sea surface at dusk and then rapidly descended and spread out into a diffuse scattering layer at 75- to 125-m depth. Shifts in resonance frequencies during migration, release of gas bubbles during migration, and strong avoidance of the vessel when maneuvering, all suggest the fish were most likely round herring, Etrumeus teres, which are common at these depths in the NMFS historical trawl survey data. An examination is made of some of the scattering characteristics of the schools and layers of these fish and comparisons of the 38-kHz data to scattering at 500-Hz bands from 1.5 to 5 kHz and 1-kHz bands from 5 to 10 kHz. [Work supported by ONR.]
Comparison of measured and calculated absorption spectra due to ensembles of fish with swim bladders
Authors: Diachok Orest
Published: July 2012

Absorption spectra derived from long-term, broadband transmission loss measurements were compared with calculated absorption spectra due to ensembles of identical fish with swim bladders over the frequency range 0.5–5.0 kHz, and near-coincident trawling data. The dominant fishes during this experiment were sardines (∼60%) and anchovies (∼30%). Only nighttime data, when the separation between these fishes is large (compared to wavelength), were considered. Measured distributions of the lengths of sardines and anchovies were separated into groups, which were of nearly uniform length—essentially year classes. Matching of measured and calculated absorption spectra yielded estimates of the number densities and Q’s of species and year classes. The spatial number densities of adult sardines, which were derived from absorptivity measurements (1.1/m2) and nearly coincident echo sounder data (0.6−1.6/m2), were consistent. The Q’s and resonance frequencies of the absorption lines, which were attributed to adult and juvenile sardines, were approximately 2.3 at 1.3 kHz and 4.7 at 3.8 kHz, respectively. These values of Q appear to be dominated by the Q0 of individual fish. Limited laboratory measurements of Q0 of other species versus fish age are consistent with the observed age dependence. [Work supported by ONR.]
Estimating the scattering contribution from microstructure and marine organisms using multiple-frequency acoustic data collected from a Gulf of Maine internal wave
Authors: Warren Joseph D. , Wiebe Peter H. , Seim Harvey E. , Stanton Timothy K.
Published: July 2012

High-frequency sound (>10 kHz) is scattered in the ocean by many different sources. Marine organisms are often thought to be the primary source of backscattered sound energy. Because of this, acoustical methods are used widely to quickly survey large areas of the ocean for the distribution and abundance of animals. Field experiments and recent theoretical work suggest that temperature and salinity microstructure in some oceanic regions could cause acoustic scattering at levels comparable to that caused by organisms. A method which uses multiple-frequency acoustic data to discriminate between biological and physical sources of scattering has been developed and applied to data collected in an internal wave in the Gulf of Maine. Model calculations show that in certain regions, scattering contributions from turbulence are equal to the contributions from animals. Using net tow information to account for the scattering from biological sources, acoustic scattering data combined with temperature and salinity profiles are inverted for estimates of the dissipation rate of turbulent kinetic energy (ε). The estimates of ε made at the depths where an internal wave occurred are several orders of magnitude higher than the ε estimates from depths above and below the internal wave.
Validity study of the distorted wave Born approximation (DWBA) model: Application to the acoustic scattering by marine organisms
Authors: Chu Dezhang , Stanton Timothy
Published: July 2012

Applications of the distorted wave Born approximation (DWBA) to the acoustic scattering by weakly scattering marine organisms have shown much progress [Chu et al., J. Acoust. Soc. Am. 93, 2985–2988 (1993); Stanton and Chu, ibid. 103, 236–253 (1998)]. Although the applicability of the model has been examined for simple objects such as spheres, cylinders, and prolate spheroids, the validity of applying the DWBA model to the acoustic scattering by marine organisms with more complicated shapes has not been studied. To evaluate the performance of the DWBA model, a systematic study of the DWBA will be presented. An in-depth study of the 1D problem reveals the fundamental difference between the exact and DWBA solutions and helps us better understand the scattering problem. By studying the internal field of 1D, 2D, and 3D problems for a more general bistatic geometry and evaluating the volume integral derived from the exact Helmholtz–Kirchhoff integral equation, we are able to estimate the validity of the DWBA model in describing the acoustic scattering by arbitrarily shaped marine organisms. [Work supported by NSF and ONR.]
Wavelet analysis comparing spectral characteristics of high frequency acoustics and hydrographic properties on Georges Bank
Authors: Fisher Karen , Wiebe Peter
Published: July 2012

Acoustic surveys of Georges Bank were carried out during the GLOBEC Broadscale program in January, March, and June of 1998 and 1999. The Greene Bomber towfish collected temperature, salinity, and fluorescence as well as the acoustics data at 120 and 420 kHz, from approximately 3 meters depth on all six cruises. With over 1200 kilometers of acoustic trackline on each cruise, covering well mixed, frontal, and well stratified water columns, a method is needed to characterize patch structures encountered. Wavelet analysis offers a computationally effective approach that can be applied to all the data obtained along the trackline. Variance analysis of the wavelet transform provides both spatial and spectral resolution simultaneously, allowing distinct consideration of spectra obtained in any spatial subset of the entire dataset. Temporal and spatial variations in the characteristic slopes and length scales of temperature, salinity, and fluorescence indicate that distinct spectral signatures exist that can be exploited to sort out physical and biological contributions. The extent to which physical and biological spectral signatures influence the wavelet variance spectra of the acoustic data is examined in each hydrographic regime.
Bubble characterization in the surf zone
Authors: Deane Grant
Published: July 2012

Breaking waves entrain bubbles ranging in radius from tens of microns to centimeters. In the surf zone, these bubbles are evident above the ocean’s surface as patches of foam that persist for a few seconds after the passage of a breaking wave. Beneath the surface, the bubbles are organized into dense plumes with void fractions of air exceeding 0.1. In the absence of additional breaking, the void fraction of air decreases to 1e-6 or less in a minute or so as bubbles rise to the surface, dissolve, and disperse. Thus, a full characterization of bubbles in the surf zone requires instruments that operate over a wide range of void fractions and bubble radii. In practice, a variety of techniques is used, and the application and results from a number of optical and acoustical instruments, including photographic techniques, travel time sonars, Doppler sonars, and acoustical resonators will be discussed. Some of the physical acoustical effects associated with the large populations of bubbles entrained by breaking surf, such as acoustic hot spots in surf noise and acoustic transmission dropouts, will also be presented.
Acoustic scattering from partially voided compliant and fluid spheres
Authors: Jankovsky Joseph C. , McCormick Ryan D. , Roy Ronald A. , Carey William M.
Published: July 2012

The presence of bubbles has been shown to change the compressibility and complex sound speed in a liquid. In the ocean, acoustically compact bubbly mixtures manifest themselves as highly compressible regions that effectively scatter low-frequency sound. To study low-frequency sound scattering, multifrequency backscattering experiments have been performed in a tank using partially voided three-quarter-inch diameter polyurethane spheres as targets. Target strengths (2-20 kHz) were measured for four spheres with void fractions of 0%, 3.4%, 4.2%, and 6%. Measured target strengths for the voided spheres were on the order of −40 to −60 dB (re 1 m). The frequency response exhibited modal structure, with peaks shifting to lower frequencies for higher void fractions. No backscatter signal was detected for the solid polyurethane sphere. Target strength was also measured for a hollow polyurethane sphere containing a suspension of bubbles in polymer gel. The void fraction was determined by fitting the scattering theory and low-frequency bubbly fluid compressibility model to the measured data. [Work supported by ONR.]
Comparing the predictions of a numerical model of SBSL in a variable acceleration environment to experiment
Authors: Thomas Charles , Wyatt Sean , Roy Ronald , Holt R. Glynn
Published: July 2012

The results of an August 1999 KC-135 SL experiment will be discussed and compared to a numerical model [Wyatt et al., J. Acoust. Soc. Am. 106, No. 4, Pt. 2, 2290 (1999)] for SL in a cubic acoustic resonator in a varying acceleration environment. The model takes into account gravitational effects and varying ambient pressure effects, and predicts the maximum bubble size, light intensity, and levitation position of the bubble. A review of and comparison to other investigators experimental results will be included. [Work supported by NASA.] a)Currently at Ford Motor Company, Detroit, MI.
Anomalous changes of sonochemical luminescence intensity under stirring operation
Authors: Mitome Hideto , Hatanaka Shin-ichi
Published: July 2012

Measurement of sonoluminescence is an effective method to evaluate a reaction field induced by intense ultrasound in a liquid. The present paper discusses changes of intensity of sonochemical luminescence from a luminol solution under various stirring conditions. A glass beaker filled with a luminol solution was irradiated by ultrasound using Langevin-type transducers attached to the bottom and side walls of a cooling bath. As in conventional chemical reactions, the intensity of luminescence was expected to increase with stirring operation. At 28 and 100 kHz, the luminescence intensity increased at a higher applied power and at a faster stirring speed. But, at 45 kHz where intense cavitation was observed in the present apparatus, the luminescence intensity decreased as the applied power increased while stirring with a flat paddle. This anomalous behavior was more pronounced at more intense stirring operation with an impeller. The authors reported the existence of upper threshold of sound pressure for sonoluminescence [Hatanaka et al., Jpn. J. Appl. Phys. 38, 3053–3057 (1999)]. The present results suggest that stirring operation affects the generation and growth of cavitation bubbles making them exceed the upper threshold in some cases, and that there is an optimum stirring motion for sonochemical reactions.
Ultrasonic motors (USM)—An emerging actuation technology for planetary applications
Authors: Bar-Cohen Yoseph , Bao Xiaoqi , Das Hari
Published: July 2012

Efficient miniature actuators that are light, compact, and driven by low power are needed to drive telerobotic devices and space mechanisms in future NASA missions. Examples of space mechanisms and devices that require actuators include robotic arms, miniature rovers, release mechanisms, positioning devices, aperture opening and closing devices, and real-time compensation for thermal expansion in space structures. These motors need to operate at various temperatures and pressures with a large range of thermal variations over a relatively short period swing. Ultrasonic rotary motors have the potential to meet this NASA need and they were developed as actuators for miniature telerobotic applications. These motors were adapted for operation in the environment of Mars, which includes very low temperatures and vacuum. A hybrid analytical model, including the influence of the rotor and stator dynamics, friction effects, and interface effects, was developed to design an efficient ultrasonic motor as a complete system. In parallel, efforts have been made to determine the thermal and vacuum performance of these motors, and effective operation at temperatures as low as −150°C and at a pressure of 16 mtorr were demonstrated. To explore telerobotic applications for USMs a robotic arm was constructed with such motors.
Factors moderating the effect of noise barriers
Authors: Meloni Tommaso , Fischer Fredy
Published: July 2012

More often than not, on noise research the dose-response relationship shows a modest explained variance. A field study was carried out to investigate the effects of 13 different noise barriers, and 500 people exposed to noise were surveyed using questionnaires. First it seems that the acoustic effectiveness of the noise barriers is responsible for the reduction in annoyance. However, a detailed analysis shows that further factors moderate the relation between the noise parameters and the reaction to noise. It seems that simply introducing a noise barrier can cause a reduction in annoyance to an extent equivalent to 5 dB. This confirms the fact that the outdoor noise levels and the acoustic design of the surroundings are among the principle parameters influencing annoyance. In addition, annoyance is determined by individual acceptance of noise barriers. The degree of acceptance splits the reaction curve with a separation around 4 units on the rating-scale of 11 units of annoyance. The design of the noise barrier partly affects this splitting. There is a higher degree of acceptance of naturally constructed and transparent noise barriers than for ones that are specially formed. Other determining factors for annoyance will be discussed.
Quiet areas and quiet facades: Important elements in the EU Noise policy
Authors: Kihlman Tor
Published: July 2012

The long-term goal for road traffic noise, Lden<55 dB, cannot be reached for all dwellings either in sprawled or in compact cities during the foreseeable future [T. Kihlman and W. Kropp, ‘‘Limits to the Noise Limits,’’ ICA, Seattle 1998]. What, then, can be done to improve the situation? One strategy is to exploit the spatial noise level variations. Even though many dwellings are exposed to Lden=65–70 dB, outdoor levels in the range 40–50 Lden are not rare in the cities: courtyards in European cities being the typical case. The EU draft directive on ambient noise puts emphasis on the protection of quietness. Quiet areas and ‘‘quiet facades’’ shall be shown on noise maps. The concept of a relatively quiet facade has been introduced. Questions to answer are: What are the effects on the annoyance and sleep disturbance when dwellings have one noisy and one quiet side? To what extent do existing, noise-exposed dwellings also have a quiet side? What are the potentials to increase also at low cost—the access to quietness in the urban renewal process? Some results from ongoing research will be presented as well as plans for further research.
Measurement and modeling of snowmobile noise and audibility at Yellowstone and Grand Teton National Parks
Authors: Menge Christopher , Ross Jason
Published: July 2012

The U.S. National Park Service is concerned about the effect that noise from snowmobiles and other over-snow vehicles has on the natural soundscapes in the National Parks. This paper addresses the measurements and modeling performed to assess both the total area in the parks where snowmobile noise would be audible and the noise intrusiveness as a function of distance from the trails. The work was performed in support of an Environmental Impact Statement that evaluated seven operational transportation alternatives in the two parks. The modeling approach computed both A-weighted sound levels and audibility continuous time histories of snow-vehicle noise at several distances from the trails. Acoustical input to the model included 1/3-oct band levels for ambient conditions, vehicle source levels, and propagation of sound over a snow-covered surface. Consequently, distances to the onset of audibility detection, areas of the parks affected, and statistics on received sound levels were calculated. The paper presents both the modeling approach and examples of results.
Risks in designing power plants to meet noise limits and how to manage them
Authors: Brittain Frank
Published: July 2012

Risks and risk avoidance affect both strategy and many choices made in designing power plants to meet noise limits. Each player typically attempts to avoid risk by passing off as many as feasible to other players. Many of these risks can readily be anticipated, but others are often unexpected. Each player—noise control engineer, engineer-constructor, owner, banker, and regulator—has somewhat different risks. Many factors can affect risks, including technical uncertainties, noise criteria, unreliable noise source data, regulatory environment, limits to the state-of-the-art, costs, schedule, any lack of experience of the responsible noise control engineer, and equipment that does not meet its noise limits. Risks are greatly increased when liquidated damages are present, the responsible noise control engineer is not adequately supported, and noise control is neglected or initiated too late in the design process. All of these factors are interrelated in complex ways. To successfully design a power plant, risks and risk avoidance should be understood, and strategies developed to reduce those risks. This paper builds on previous papers in the Special Session, reviews the risks of each player, and suggests strategies to reduce risks. Further, the ways in which risk affect the design process are identified.
Strategy for writing procurement specifications
Authors: Hessler George F.
Published: July 2012

The key word for writing workable procurement specifications is clarity. The recipient is much more interested in responding when the specification requirements are understood and unambiguous. As a minimum, the procurement specification must describe the starting point and end result specified by the author. The method of test verification and allowable tolerances, if any, is critical and must be defined in the procurement specification. Current acoustical requirements for power plant equipment must be specified in the near and far field with a clear order of precedence if there is a conflict between the two locations. The trend today for specifying far-field sound levels is to limit the specified parameter to the overall ‘‘A’’-weighted sound level. Since this parameter offers no chance of preventing excessive low-frequency noise, the ‘‘C’’-weighted limit, as a minimum, must also be concurrently specified for all types of power plants.
The Acoustical Society of America program in standards
Authors: Schomer Paul
Published: July 2012

The Acoustical Society of America (ASA) Standards Secretariat has the delegated authority of the American National Standards Institute (ANSI) to manage the development of national standards, to provide for the USA input to the development of international standards, and to manage the development of certain international standards. First, the ASA Standards Secretariat manages the four ‘‘S’’ committees that develop ANSI Standards (national standards) using the consensus method. The four S-committees include S-1 (acoustics), S-2 (mechanical vibration and shock), S-3 (bioacoustics), and S-12 (noise). Second, the ASA Standards Secretariat manages the US representation to several International Organization for Standardization (ISO) and International Electro-technical Commission (IEC) technical committees including ISO TC 108 and 6 of its subcommittees, ISO TC-43 and TC-43-subcommittee 1, and IEC TC 29. Liaison representation from the Society of Automotive Engineers (SAE) and the American Society for Testing and Materials (ASTM) is relied on, in part, to perform this function. Third, the ASA Standards Secretariat provides the international secretariat for ISO TC-108 and two of its subcommittees. This paper discusses the role and program of the ASA Standards Secretariat.
An outline of a proposed acoustic holography system based on the Helmholtz equation–least-squares (HELS) method
Authors: Rayess Nassif E. , Wu Sean F.
Published: July 2012

The Helmholtz equation–least-squares (HELS) method [Wang and Wu, J. Acoust. Soc. Am. 102, 2020–2032 (1997); Wu, J. Acoust. Soc. Am. 107, 2511–2522 (2000)] has been proven a reliable acoustic holography method. The main advantages are its simplicity in formulations, flexibility in measurement locations, and uniformity in algorithm for a variety of source geometry and conditions. This paper presents a complete acoustic holography system based on the HELS method that makes full use of these advantages. This system has been under development as part of an ongoing research at the Acoustics, Vibration, and Noise Control Laboratory at Wayne State University. The physical setup will be described which includes the front-end multichannel data acquisition system and the associated hardware. Experimental results on reconstruction of the radiated acoustic fields from a complex source using this system will be demonstrated. Comparisons of this system with other acoustic holography systems currently available will be made. [Work supported by NSF.]
Diagnostics of vibration and noise via Fourier transforms: A new approach
Authors: Gelman Leonid M. , Petrunin Ivan V. , Shirkov Vladimir T.
Published: July 2012

A new general optimal approach and new diagnostic features are proposed, for those cases where one- and multidimensional Fourier transforms are used for diagnostics of vibration and noise. For the forced oscillation vibroacoustical diagnostics method with Gaussian excitation, the optimal nonlinear transformation of the proposed features is received. It was shown (1) The power spectral density is optimal transformation for considered diagnostics only for specific situations; (2) The phase spectrum is not optimal transformation for considered diagnostics; and (3) The proposed approach provides the increment of diagnostics effectiveness in contrast with usage of power spectral density. This is in contrast to most applications concerning diagnostics of vibration and noise, where power spectral density is used.
Gemination in Italian: the GEMMA project
Authors: Di Benedetto Maria-Gabriella
Published: July 2012

The Gemination project (GEMMA) started at the University of Rome La Sapienza, Italy, in 1992, examined gemination in Italian. The analyzed consonants were stops, liquids, fricatives, nasals, and affricates. GEMMA was completed in 2000. Partial results were previously reported [stops: Esposito, DiBenedetto (1999), liquids: Argiolas et al. (1995), fricatives: Giovanardi, DiBenedetto (1998), nasals: Mattei, DiBenedetto (2000), affricates: Faluschi, DiBenedetto (2000)]. The major findings were coherent in all studies: gemination is revealed by time-related parameters, namely, the consonant lengthening and the preconsonant vowel shortening in geminate forms. Relevance of acoustic correlates was confirmed by perceptual experiments [A. Esposito and M. G. DiBenedetto, J. Acoust. Soc. Am. 106, 411–422 (1999); F. Argiolas et al., J. Acoust. Soc. Am. 97, 3418 (1995); M. Giovanardi and M. G. DiBenedetto, Eur. J. Language Speech 1–13 (1998), http://web-sls.essex.ac.uk/web-sls; M. Mattei and M. G. DiBenedetto, Eur. J. Language Speech 1–14 (2000), http://web-sls.essex.ac.uk/web-sls; S. Faluschi and M. G. DiBenedetto, Eur. J. Language Speech (submitted)].
Spectral characteristics of /s/ and /∫/: Rate effects in Parkinson’s disease
Authors: Tjaden Kris , Kleinhaut Jessica , Kozak Alexa
Published: July 2012

Comtemporary speech production theory proposes that speakers adjust rate to enhance or maximize acoustic-perceptual distinctiveness for listeners. In fact, the suggestion that rate impacts acoustic-perceptual distinctiveness is one rationale for using rate manipulation as a therapy to improve speech intelligibility in dysarthria. The relationship between rate manipulation, acoustic measures of production, and perceptual impressions of speech in dysarthria is poorly understood, however. For example, some studies report rate-induced acoustic changes in speech that are systematically tied to perceptual impressions. Other studies report no effect of rate on speech production characteristics in dysarthria. Further study of the relationship between speech production measures and rate variation in dysarthria therefore appears warranted. The present study examined spectral characteristics of word-initial /s/ and /∫/ produced at a variety of rates by speakers with hypokinetic dysarthria associated with Parkinson’s disease. Healthy speakers were studied for comparison purposes. Fricatives were produced in the words shores, shies, size, and soys embedded in a carrier phrase. A graded rate task was used to elicit an extensive range of rates. Spectral moment coefficients were used to characterize fricatives; phrase duration was used to index rate. The relationship between rate variation and spectral moment coefficients was quantified via regression analysis.
The development of human standards to limit noise-induced hearing loss: A good model for animals?
Authors: Bowles Ann E. , Johnson Daniel L.
Published: July 2012

Over the past 50 years, the ASA and other organizations have promulgated standards to protect human hearing. We are evaluating these standards as a model for similar standards for animals. First, we must eliminate noise at frequencies that could have little effect on hearing. In the case of humans, A-weighting has been selected for most applications. The choice was determined partly by convenience (readily available circuitry, computationally simple calculations for weighted values) and partly by its robustness in fitting empirical data. Second, allowable exposures must take into account exposure time. For humans, the time-intensity tradeoff is calculated on an equal-energy basis that presumes underlying linear functions (the basis of the 3-, 4-, and 5-dB exchange values used by various organizations), again to simplify computation. For high-amplitude, brief transients (impulse noise), which produce nonlinear auditory responses, an absolute upper limit of exposure is used. This scheme has proved adequate to protect crucial human hearing capabilities (mainly the understanding of speech), but may not be conservative enough for animals, which use their hearing in self-defense, for navigation, etc. It is interesting to note that schemes for animals can be developed without the computational simplicity that historically drove many decisions in the human case.
A preliminary study of loudness at frequencies of 5 to 120 kHz based on whistle response time (RT) in a dolphin
Authors: Ridgway Sam , Carder Donald
Published: July 2012

Stebbins (1966) showed that auditory RT of monkeys could be used to measure loudness. Such studies have been replicated in other animals and humans. Although Ridgway et al. (1991) reported that dolphin auditory RT varied with stimulus intensity, curves showing variation in RT with frequency and amplitude were not presented. Choice RT was measured in a female bottlenose dolphin responding to 300 msec bursts of clicks (30 clicks at 10 ms ISI) with a burst of pulses, and to 300 msec tones with a whistle. Responses were received with a hydrophone (B&K 8103), digitized, and stored on disk. The dolphin responded correctly (whistled to the tone, pulsed to the pulses) on more than 98% of presentations. Here we only consider tone presentations. Frequencies, presented randomly, were 5, 10, 20, 40, 60, 80, 100, and 120 kHz and ranged from 85 to 135 dB re 1 Pa rms. At 10 kHz, median RT ranged from 240 msec at 135 dB to 410 msec at 85 dB. At 100 kHz, median RT ranged from 260 msec at 135 dB to 330 msec at 85 dB. Studies must be done over a larger range of amplitude and frequency and with precise control of background noise.