bluuebunny/crossref_metadata_2025 huggingface dataset:
Noise standards for the workplace
Authors: Melnick William
Published: October 2005

All four of the American National Standards Committees for which the Acoustical Society holds the secretariat are active in developing standards directly applicable to the workplace. S1 (Physical Acoustics) is involved with standards for equipment used to specify noise conditions including sound level meters and personal dosimeters. S2 (Shock and Vibration) has a joint interest with S3 (Bioacoustics) in standard procedures for describing human exposure to mechanical vibrations and shock. S3 has a major concern in standards relating to measurement of hearing loss and establishing the risk posed by occupational noise to hearing. S12 (Noise) is in the process of producing standard methods for measurement of noise in the workplace, evaluating hearing protectors, and evaluating the effectiveness of industrial hearing conservation programs. The status of these standards activities as well as others which directly or indirectly have an impact on problems of occupational noise is the subject for this presentation.
Noise standards for land use planning
Authors: Galloway William J.
Published: October 2005

Standards for assessing the compatibility of various land uses with an acoustical environment have been a developmental goal of national and international standards producers for over 20 years. Acoustical Society publication of S3.23-1980 was the first major accomplishment in these efforts. Related international standards are now emerging. A standard for use with high intensity impulsive noises is under development in S12. The evolution of these standards and their uses by regulatory agencies are discussed in this paper.
Sound speed measurements in liquid oxygen-liquid nitrogen mixtures
Authors: Zuckerwar Allan J. , Mazel David S.
Published: October 2005

The transfer of liquid oxygen (LOX) from a storage vessel to a rocket engine generally requires the use of a pressurizing gas like nitrogen at a typical pressure of 3000 psi. The condensation of gaseous nitrogen to the liquid (LN2), combined with high miscibility, results in contamination of the LOX, which has a deleterious effect on engine performance. It has been proposed to monitor the LOX contamination through sound speed measurements. The purpose of this study is to measure the sound speed of LOX-LN2 mixtures under controlled conditions and to utilize the results in a practical LOX contamination monitor. The measurements, performed by the pulse-echo technique on several LOX-LN2 compositions, reveal a slight deviation from a linear dependence of the sound speed upon the mole fraction of LN2. The results for pure LOX and pure LN2 at − 195.8 °C and 1 atm pressure are 1008.5 ± 0.25% and 852.8 ± 0.32% m/s, respectively, and these are compared to measurements reported in the past.
Detuning/dephasing instabilities in acoustic levitation and Rayleigh disk systems
Authors: Garrett S. L. , Barmatz M.
Published: October 2005

The equation of motion for an acoustically levitated sample or Rayleigh disk in a resonant cavity is equivalent to a mass on a spring with a variable spring constant. The variation in the spring constant for a fixed drive frequency line with sample position (disk angle) [M. Barmatz, J. L. Allen, and M. Gaspar, J. Acoust. Soc. Am. 73, 725–732 (1983)]. The acoustic restoring force (disk torque) and sample displacement (disk angle) become dephased due to the nonzero response time (Q/πf) of the cavity. Due to this retardation, the modulated acoustic force (disk torque) can do either positive or negative work on the sample, leading to instability or superstability (enhanced damping). Simple calculations of the instability threshold and initial growth rate will be presented along with more detailed computer calculations. A video tape illustrating the instability in a ground-based levitation system will also be shown. [Work supported by NASA.]
Recent experimental developments in the study of the newly discovered nonpropagating hydrodynamic solitons
Authors: Wu Junru , Rudnick Isadore
Published: October 2005

The central mechanism for creating a nonpropagating hydrodynamic soliton is that a nonlinear dispersive system has an amplitude dependent resonant frequency such that the higher the amplitude the lower the resonant frequency [J. Wu, R. Keolian, and I. Rudnick, J. Acoust. Soc. Am. Suppl. 1 74, S11 (1983); Phys. Rev. Lett. 52, 1421 (1984)]. The finite amplitude tuning curves of a rectangular section surface gravity wave resonator have been determined for various liquid depths. It is found that the direction of the bending of the tuning curve depends on the liquid depth. For deep liquid it bends toward lower frequencies. For shallow liquid it bends toward higher frequencies. The crossover depth was found to be 6 mm for the 2.8-cm-wide resonator. Theoretical analysis, done by Seth Putterman and Andres Larraza in this laboratory, yields the value to be 9 mm. The free decay rate of the soliton was measured. The characteristic exponential decay time is two thirds that of a small amplitude decaying wave. [Work supported by ONR.]
A surface wave instability on liquid helium and water
Authors: Keolian Robert , Rudnick Isadore
Published: October 2005

Nonlinear systems tend to display increasingly more complicated behavior as they are driven harder and harder. In such an experiment presented here, surface waves are parametrically generated when a trough, partially filled with liquid He4 or water, oscillates vertically. These waves become modulated at independent frequencies that appear one by one, and that may or may not phase lock on each other, as the drive amplitude is further increased. The modulations are the result of energy flowing into the lowest modes of the trough, despite the modes' response being unsynchronized to the drive. [Work supported by ONR.]
An ultrasonic scattering technique for microparticle characterization
Authors: Roy Ronald A. , Apfel Robert E.
Published: October 2005

A modified technique is presented for determining the physical properties of individual microparticles such as biological cells. Two submerged confocally positioned transducers (one transmitter/receiver and one receiver) generate 30-MHz center frequency tone bursts which scatter off of single particles convected by a coaxial jet flow. The scattered pressure is measured at 90° and 180°, analog envelope detected, digitized, and stored in computer memory. By employing a long wavelength acoustic scattering theory first developed by Raleigh, it is possible to calculate the particle density and compressibility given a priori knowledge of both the particle volume and the physical properties of the host liquid. This apparatus, which is still in the developmental stage, is simpler and more versatile than an earlier, three-transducer system developed by Mark Roos [Doctoral dissertation, Yale University (1983)]. The system performance and theoretical scattering model are evaluated using calibration particles (e.g., polystyrene spheres, liquid drops) and biological cells. [Work supported by NIH through grant number R01-GM30419 and by ONR.]
Topography in the auditory and other sensory systems
Authors: Kaas Jon H.
Published: October 2005

The goal of the presentation will be to describe and discuss basic and common features of sensory representations in the auditory, somatic, and visual systems of mammals. Each system consists of a number of interconnected representations of a sensory surface. Most representations are simple or first-order transformations, although higher-order representations occur. Advanced mammals may have more representations than primitive mammals, so that only some are homologous across species, while others evolve in certain lines. The borders of adjoining representations typically are matched for the same locations along a sensory surface. Such congruent borders suggest an activity dependent developmental mechanism. Within some representations for some species, there is now considerable evidence for modular organization. Thus, primary visual cortex of monkeys has bands of orientation, specific neurons, and occular dominance neurons. Area 3b of somatosensory cortex of monkeys has bands of slowly adapting and rapidly adapting neurons, and primary auditory cortex in cats has bands for alternating types of binaural neurons. These types of modular organization may not exist, however, in the same fields in a number of other mammalian species. Representations can be characterized in terms of fidelity and receptive field scatter, receptive field size, and proportions devoted to equal divisions of the receptor surface (magnification factors). When such features are considered, general rules emerge.
Acoustic radiation from beams under the action of distributed driving forces
Authors: Keltie R. F. , Peng H.
Published: October 2005

The importance of the spatial extent of applied forces in the radiation of sound from structures was studied through formulation of the sound power radiated by a line force acting on a infinite elastic beam. The expression for sound power was integrated numerically and the results examined as a function of kL, the acoustic length of the force, and the wavenumber ratio. Below coincidence the power was found to be generally proportional to (kL)−2. Near and at coincidence, sufficiently large force scales produced a significant effect on the power. In particular, when the length of the force corresponded to an integral multiple of the critical wavelength, the coincidence peak was completely suppressed. Above coincidence, minima in the sound power occurred when the force length was a multiple of the wavelength of the free bending wave. These minimal values of power were shown to be nearly equal to the power radiated far below coincidence. These results are discussed in terms of the coupled structural-acoustic wavenumber response function and the wavenumber spectrum of the applied force. [Work supported by NSF.]
Plate vibration identification using statistical signal analysis
Authors: Mielnicka-Pate Anna
Published: October 2005

Theoretical and experimental investigations of baffled plate vibrations and radiated acoustic pressure were performed. The goal of these investigations was to evaluate the acoustic radiation due to each of two different excitation forces in the case when both of them were applied at the same time. A 0.25-in.×2-ft×2-ft aluminum plate, simply supported at the center, was installed inside an anechoic chamber. Two concentrated forces were applied using vibration excitors. The two input-one output, linear model and the statistical signal analysis approaches were used in the analysis. Excitations were noncorrelated, random signals. Three different input signal representations were used for comparison. These signals were force, acceleration, and acoustic pressure measured in the vicinity of the excitor-plate connections. The statistical analysis was performed using two dual-channel FFT analyzers interfaced with a personal computer to form a four-channel system. The performance tests for this four-channel system will also be discussed in terms of time domain and frequency domain data calculations.
The power radiation from line forced fluid-loaded plates
Authors: Innes D.
Published: October 2005

In the past, most studies of the effects of fluid loading on the response of time harmonic line forced plates have involved either “ad hoc” simplifications whose adoption was justified on physical grounds alone or numerical techniques and restricted frequency ranges below the “coincidence” frequency. We use the method of Matched Asymptotic Expansions (MAE) to obtain a series of simple analytic expressions which cover overlapping regions of the whole frequency range. A composite expression is easily formed for the radiated power. This gives a simple single expression, uniformly valid for all frequency ranges, and yields predictions for the radiated power in good agreement with the corrected curves of Nayak [J. Acoust. Soc. Am. 49, (1979)]. [Work supported by ONR Code 425.]
Acoustic analysis and perceptual effect of variation in the amplitude envelopes of /b/ and /w/
Authors: Nittrouer Susan , Studdert-Kennedy Michael
Published: October 2005

Relative energy change at consonantal release has been proposed as an acoustic property, invariant across vowel contexts and speakers, to distinguish between stops and glides [M. Mack and S. E. Blumstein, J. Acoust. Soc. Am. 73, 1739–1750 (1983)]. We followed the procedures of Mack and Blumstein to measure distributions of energy in /bV/ and /wV/ syllables, spoken by two speakers before five vowels. Results for one speaker matched those of Mack and Blumstein; results for a second speaker did not. In a subsequent perceptual experiment, amplitude envelopes of /bV/ and /wV/ syllables containing the same vowels were crossed. Envelope crossing had little effect on the syllables of one speaker: Nearly all were perceived as originally produced. For the second speaker /w/ to crossing also had little effect, but /b/ to /w/ crossing elicited more than 75% /b/ responses, particularly before /a/. Thus although relative energy change at consonantal release may separate /b/ from /w/, acoustically and perceptually, in some contexts, for some speakers, it is evidently not invariant. [Work supported by NICHD.]
Perception of initial glides by impaired- or normal-hearing listeners
Authors: Revoile S. , Holden-Pitt L. , Edward D. , Pickett J. M.
Published: October 2005

An experiment was conducted to study the use of cues to glide consonant identification by hearing-impaired (n = 22) and normal-hearing (n = 6) listeners. The syllables /wæk, jæk, bæk, dæk, gæk, æk/ (six different utterances each) were identified for three conditions: (1) unmodified, (2) initial glide murmurs or stop bursts removed, and (3) syllables cut back to the ninth pitch period from the vowel onset. The normal group, listening at 75 or 95 dB SPL, showed 100% glide phoneme perception for the condition of deleted glide murmurs or stop bursts. For this condition performances varied greatly within the hearing-imparied group (listening at MCL): Near-normal glide phoneme perception was seen for less than 20% of the impaired listeners (mean 3FA = 72 dB HL), indicating good use of the vowel onset transitions for glide perception by these listeners. Between the conditions: Unmodified versus glide-murmur/stop-bursts deleted, the majority of the hearing-impaired listeners (mean 3FA = 88 dB HL) manifested degraded manner and/or place and/or phoneme perception. For these listeners reduced perception of the duration and/or frequency extent of F1 and/or F2 vowel onset transitions was suggested by the types of consonant confusions evidenced. About 20% of the impaired listeners (mean 3FA = 92 dB HL) showed no differences in performance among the three conditions, indicating inability to distinguish the presence/absence of vowel onset transitions that characterize initial glides.
Duration of frication noise as a perceptual cue
Authors: Jongman Allard
Published: October 2005

Natural speech CV syllables ([f, s, š, ō, v, z, ð] in the environment of [i, u, a]) were computer edited to include 20–70 ms of frication noise as measured from its onset in 10-ms steps, as well as the entire frication noise. These stimuli were presented to 12 subjects for consonant identification. Results showed high recognition scores (>75%) for all fricatives but [ō, ð] in the longer conditions (60 and 70 ms and the full frication noise). In the remaining conditions scores, although lower, were still significantly above chance. Perception of manner of articulation seemed to be minimally affected by a decrease in frication duration, with 86% correct scores in the 20-ms condition. Perception of place of articulation was somewhat more affected by duration of the stimuli, with correct identification falling to 60% in the 20-ms condition. Results suggest that while a minimum duration of about 20 ms is required for perception of manner of articulation, frication duration is not an important perceptual cue to either place or manner. Instead, spectral rather than temporal properties provide the major cues for place and manner of articulation for consonants.
Shadowing fluent speech: Detecting mispronunciations of word-initial consonants
Authors: Small Larry H. , Bond Z. S.
Published: October 2005

A shadowing task was employed to investigate normal listeners' ability to detect alterations in word-initial consonants. The same 600-word prose passage, containing 14 two-syllable target words with syllable-initial stress, was employed in three separate experimental conditions so that the word-initial consonant was either altered by: (1) a one-distinctive feature change [N. Chomsky and M. Halle, The Sound Pattern of English (Harper and Row, New York, 1968)], (2) a three-distinctive feature change, or (3) completely deleting the word-initial consonant. The target words were selected to be predictable from context and were examined for frequency of occurrence in English. There were 16 subjects in each condition. The subjects' shadowed responses were recorded on tape and analyzed in terms of fluent restorations of the altered consonants. Statistical analysis of the subjects' responses revealed no difference in number of restorations observed in either distinctive feature condition. However, subjects in the consonant deletion condition showed a significant number of restorations when compared to subjects' responses in the two distinctive feature conditions. The subjects' shadowing behavior can be explained in terms of whether word-initial phonetic information is altered by mispronunciation or by complete deletion.
F
1 transition as a cue to [± voice] in a following utterance-final stop
Authors: Walsh Thomas , Parker Frank , Miller C. J.
Published: October 2005

Previous studies have shown that the cues of [± voice] in an utterance-final stop produced without release or vocal vibration during closure include duration of the previous vowel and presence or absence of a falling F1 transition [T. Walsh and F. Parker, J. Phonet. 12, 207–218 (1984)]. Raphael [J. Acoust. Soc. Am. 51, 1296–1303 (1972)] employed synthetic speech to measure the perceptual effect of varying vowel length while holding F1 slope constant. The present study is intended as a complement to Raphael. That is, our study measures the perceptual effect of varying F1 slope at given vowel durations. The stimuli consist of three-formant tokens of bat/bad, synthesized without release or closure voicing for the final stop. The vowel /æ/ was chosen because of its high F1, which would allow maximum manipulation of the F1 transition. Each token is synthesized with three durations, corresponding to those in Raphael which cued, respectively, [−voice], mixed, and [+ voice] responses. For each duration tokens are synthesized with F1 transitions having varying slopes and onsets. The perceptual effect of variation along each parameter, as well as the interrelationship between various parameters will be discussed. [Work supported in part by NIH.]
Psychoacoustical spectra of French velar consonants
Authors: Sorin Christel
Published: October 2005

The goal of this experiment was to compare the representation of speech sounds obtained using psychoacoustical measurements with those furnished by the model of the peripheral auditory system developed by Delgutte [in Representation of Speech in the Peripheral Auditory System, edited by R. Carlson and B. Granström (Elsevier, New York, 1982), pp. 131–149]. We studied the perceptual representation of the initial 16 ms of the burst of the consonant /k/, in three vocalic contexts /a/,/i/, and /u/, using ipsilateral simultaneous masking. The masker was one of the three VCV sequences /aka/, /iki/, and /uku/, extracted from natural speech. The test sound was a tone burst with a duration of 16 ms and with a fixed frequency ranging from 0.840–3.400 kHz, by critical-band steps. The test tone was located just at the beginning of the burst. The registered level of the just-audible test tone allows one to obtain the “psychoacoustical” spectra of the beginning of the consonant burst for the three vocalic contexts. These spectra will be compared with the LPC spectra of the same portion of the signal and with “model rate profiles” (i.e., simulated average discharge rate as a function of the characteristic frequency) obtained at the output of Delgutte's model. This comparison allows for a first pyschoacoustical calibration of the model adapted to the study of speech sounds.
Auditory correlates to phonetic features: Results of a modeling study
Authors: Goldhor Richard
Published: October 2005

A model of the peripheral auditory system was used to study two sets of speech tokens for which perceptual data exists. One of these sets exhibits a contrast between initial stop and glide (ba/wa), the other between intervocalic voiced and voiceless stop (rabid/rapid). Simple properties of the modeled peripheral auditory response can be identified, which are strongly linearly correlated with listeners' perception of the phonetic contrasts contained in these sets. Two fundamental characteristics of neural response play an important part in these auditory correlates: adaptation of firing rate due to sustained stimulation and spontaneous firing in the absence of stimulation. The results of this study support the theory that the transformations of the peripheral auditory system play an important role in speech perception.
Recognition of English sound contrasts by Arabs
Authors: Mitleb Fares
Published: October 2005

It seems to be widely accepted that there is a biologically determined critical stage for language acquisition in humans during childhood [Slobin (1956, 1971)], indirectly providing support for the observations of language teachers that it is almost difficult to acquire a second language thoroughly after the age of 12 or 13. Such conclusions, however, raise the question of the extent to which remedial training can reverse the diminution of discriminative ability in the course of second language acquisition. Natural speech stimuli were presented to two groups of Arabs majoring in English: (1) relatively inexperienced Arabs and (2) experienced Arabs. Our results show that the experienced group acquired better recognition of English sound contrasts than the inexperienced one. Thus we provide support for the findings of Flege (1983) that the more experience the non-native speakers gain in the second language, the better discriminative ability is noted. [Research supported by Yarmouk University.]
Underwater sound generation by breaking wind waves
Authors: Kerman Bryan R.
Published: October 2005

In a recent paper [B. R. Kerman, J. Acoust. Soc. Am. 75, 149–165 (1984)] the mechanism of sound generation by forced oscillation of bubbles by turbulence was discussed. It was argued that the most intense sound originated from bubbles of radius comparable to the Kolmogorov scale of the turbulence. The consequences of this aspect of the model in terms of the resulting audio spectrum are examined. An extension to the concept of intermittent forcing by shedding wake vortices behind rising bubbles will be outlined. As well, corrections to the original formulation for the source depth and effective turbulent forcing will be discussed.
Standards and test codes for individual noise sources
Authors: Baade Peter K.
Published: October 2005

Meaningful noise measurements require more than the precise measurement of the sound level at some point in space at a particular instant of time. The additional considerations which apply to measurements of the noise emission of individual stationary sources fall into two categories: (1) Installation and operation of the source so that its noise emission is relevant to the purpose of the test. (2) Acquisition and processing of sufficient data to extract the information desired. The first category is the responsibility of industry-specific sound test codes. Such test codes need not go into any detail concerning the acoustical measurements since these are covered by a coordinated set of ANSI Standards for which the Acoustical Society of America is responsible. The present paper provides an overview of the relevant ANSI Standards (and their ISO counterparts) in order to help the writers of a sound test code determine which part of the set is most appropriate for the particular type of source to be tested. The proper selection of a descriptor and other provisions of ANSI Standard S12.1-1983 will also be discussed.
Airport noise compatibility planning—A program that works
Authors: Hixson Robert B.
Published: October 2005

The Federal Aviation Administration's FAR Part 150 Airport Noise Compatibility Planning Program is an effective program that is on-line and working. It establishes standard noise methodologies and units (LA, dBA, and Ldn), establishes the Integrated Noise Model as the standard airport noise-modeling methodology, identifies land uses normally compatible with various levels of airport noise, and provides for voluntary development and submission of Noise Exposure Maps and Noise Compatibility Programs by airport operators. An 8% set-aside of airport grant funds is provided for development and implementation of the programs, including soundproofing as well as purchases of properties. After a slow initial start-up cycle, 19 Noise Exposure Maps or Noise Compatibility Programs have now been submitted, and 11 maps and 5 programs have received approval. Federal grants have been issued to 19 airports to develop noise compatibility programs or to implement approved programs. Some 22 programs are expected to be submitted during fiscal year 1985. The FAA will hold a national planning conference in October 1985 to assess the program's future needs and directions.
Night air cargo operations flyover noise mitigation by a municipality
Authors: Campanella Angelo J.
Published: October 2005

A 1981 Air Force Draft Environmental Impact Analysis (DEIA) on converting Rickenbacker Air National Guard Base (RANGB, formerly Lockbourne Air Force Base) to a civilian air terminal operated by a new county port authority (RPA) indicated that the DNL increase would be insignificant. In 1982, residents of the central Ohio village of Groveport (1.7 miles from the landing threshold of RANGB Runway 22) showed in federal court that military air activity was not as noisy as modeled in the DEIA, ceased after 11:00 pm and did not resume until 8:00 or 9.00 am the next day. Noise monitoring near Dayton's Municipal Airport where Emery Air Freight operates found five hourly Leq's which ranged from 63 to 73 dBA and peaks from 74 to 94 dBA. For the same times, Groveport hourly Leq's were about 45 dBA with 50- to 65-dBA peaks. The proposed civilian air cargo carrier projected 26 round trips per night by heavy aircraft such as the DC-8 and the Boeing 727. Their night noises would be disruptive to sleep since not all houses had adequate noise insulation and aircraft noise abatement procedures could not be adequate. The court ruled that the Air Force EIA DNL values be made more accurate and RPA should promulgate a noise mitigation plan for Groveport's approval. Beyond feasible aircraft noise abatement procedures, the plan is that within the 90 SEL contour of the noisiest tenant aircraft and where night overflight noises in sleeping quarters exceed 55 dBA, residences shall be insulated or purchased by the RPA. Outside the 90 SEL contour, only houses where the interior noise peak exceeds 55 dBA an arbitrated number of times per night are included. Civilian air cargo operations have not started.
Time-of-flight distributions for pulses propagating through random media
Authors: Flatté Stanley M.
Published: October 2005

The distribution of travel time for pulses propagating through a random ocean is obtained. The difference between distributions obtained by weighting each pulse with its intensity, or plotting a histogram of the number of pulses regardless of intensity, is discussed. The difference between distributions obtained for discrete scattering media such as particulates, and continuous media such as an internal-wave field, is discussed. These results have relevance to the use of travel-time observations to determine the statistical characteristics of random media, such as in internal-wave acoustic tomography. They also relate to mesoscale tomography, in that internal waves introduce a bias of order 10 ms for 1000-km rays in the ocean. [Supported by DARPA and ONR.]
Tomographic observation of depth averaged current and temperature in the Florida Straits
Authors: DeFerrari H. A. , Ko D. S. , Monjo C.
Published: October 2005

A tomographic approach for the measurement of range and depth averaged current and temperature is successfully demonstrated for the bottom limited acoustic transmission of the Florida Straits. The shallow water environment prohibits the use of deep ocean tomography methods since there are usually no observable separable arrivals associated with eigenrays. Instead, multipath groupings of arrivals are shown to have stable envelopes if averaged sufficiently long to eliminate effects of interference. The shape of the envelope is controlled to some extent by the source receiver depth and has characteristics which can be used for very precise travel time measurements. Ray models predict a unique relation between ray height above the bottom and arrival time allowing for unambiguous inversion. Two three-point reciprocal transmission experiments were conducted in the Florida Straits (ranges approximately 25 and 45 km). Two-way channel pulse responses are analyzed to give travel times which are then inverted to give depth averages of temperature and current and the depth of the average is determined by ray models. The method is shown to be precise in resolving variations in temperature of 0.02 °C and current of 2 cm/s. The spatially averaged tomographic results are compared with point measurements of current and temperature from current meter moorings along the path of propagation.
Self-similar solution for spherical weak shocks
Authors: McDonald B. Edward , Ambrosiano John
Published: October 2005

The nonlinear progressive wave equation (NPE), recently developed for investigation of weak shock refraction [B. E. McDonald and W. A. Kuperman, Proc. Ocean Acoust. Workshop, edited by D. Lee and M. Schultz (Yale Univ., 1–3 August 1983)], admits similarity solutions appropriate to spherically symmetric explosions. The NPE reduces the second-order wave equation with lowest-order nonlinear correction to a first-order initial value problem in time (i.e., the forward propagating characteristic is automatically selected while the backward propagating one is eliminated). When refraction is absent, the NPE admits an analytic, closed form similarity solution with similarity variable x = r/ct. Results for peak pressure and relaxation time versus range closely resemble those of P. H. Rogers [J. Acoust. Soc. Am. 62, 1412–1419 (1977)] who assumed the pulse shape to be initially exponential. (Our solution predicts the actual form of the self-similar pulse within a constant of integration.) Both our results and Rogers' show good agreement with pressure data, but only fair agreement with relaxation time data. This seems to call for some unspecified change in the theory or perhaps a reinterpretation of the experimental data. [Work supported by ONR.]
Acoustic modes of 3-D musical instrument cavities calculated with 1- and 2-D finite elements
Authors: Bernhard R. J. , Price S. M. , Seidel M. R.
Published: October 2005

The acoustic behavior of the three-dimensional cavities of musical instruments can be studied using the acoustical finite element method. For some cases, one- and two-dimensional finite element models may be used, resulting in more efficient computations and a simplification of the input. The 1-D model is used for long, cone shaped cavities found in flutes, woodwinds, and brass instruments. Guitars, violins, and instruments with a small, but variable, change in height can be studied by the 2-D model. Analytical models incorporating elemental geometries with lossy behavior have been used in the past for the quasi 1-D case of woodwind instruments. A 1-D finite element program was used for similar problems where the axisymmetric cavity was long with respect to its cross section. Tone holes are included in the model by using empirically determined impedance functions applied as boundary conditions. A 2-D finite element program was written which incorporates the height of the cavity as a parameter at the nodes. The procedure correctly predicts frequencies and mode shapes of cavities with gradual changes in height. Limitations for the permissible rate of change in height are demonstrated.
Diffraction optic and x-ray techniques of cavitation research
Authors: Besov A. S. , Berngardt A. R. , Kedrinskii V. K. , Pal'chikov E. I.
Published: October 2005

This experimental investigation is devoted to bubble cavitation development in the samples of distilled water under the action of intense rarefaction waves. In the experiments two types of shock tubes were used, with the shock waves generated in liquid by (i) the impact of a piston onto an unmovable liquid, or (ii) moving a conductive disk accelerated by a pulsed magnetic field. An initial dynamics and parameters of microinhomogeneities were determined from the measured scattered radiation intensity (λ = 0.63 mcm) of a He-Ne laser. It has been found that the centers of ∼1.5 mcm size give an essential contribution into scattering. A total number of inhomogeneities is about 105 cm−3. An experimental analysis shows that at least a portion of microinhomogeneities represents microbubbles of free gas. The x-ray method allows us to determine an initial moment of liquid fracture and dynamics of its structure for a volumetric concentration of gas phase of 2%–4% and higher. The computer proceeding of the roentgenograms is presented.
Nonlinear pulsations of vaporous cavitation bubbles
Authors: Nicholas R. E. , Finch R. D.
Published: October 2005

The equations governing the motion of vapor bubbles in a sound field were formulated earlier [R. D. Finch and E. A. Neppiras, J. Acoust. Soc. Am. 53, 1402–1410 (1973)], and linear oscillatory solutions of the equations were obtained. Nonlinear solutions have now been obtained, using a numerical method, and some typical results will be presented. Some of these results are in accordance with the linear oscillatory solutions but some are not. These nonoscillatory solutions can be associated with an exponential type of linear solution. Both collapse and growth of an exponential nature are predicted.
Pitch classes differ with respect to height
Authors: Deutsch Diana , Moore F. Richard , Dolson Mark
Published: October 2005

Departments of Music, University of California, San Diego, La Jolla, CA 92093 The pitch of a tone is considered to consist of two components: the rectilinear component of height, and the circular component of chroma, or pitch class. In an experiment employing simultaneous sequences of Shepard tones, it is shown that tones in different positions on the chroma circle differ in height when generated under the same spectral amplitude envelope. Further, the directions of these differences remain constant when the envelope is centered at different positions along the spectrum, resulting in clear differences in the overall heights of the patterns. Implications of these findings for theories of pitch perception are discussed. [Work supported by NIMH.]
Tonality perception and comprehension: Pitch-interval interactions
Authors: Christopherson Frank D.
Published: October 2005

Two experiments investigated the influence of pitch and melodic interval on tonal comprehension and melodic expectation. The stimulus examples for both experiments were composed of a tonal context example followed by a two-tone melodic fragment. The two-way factorial design had 12 levels of ending pitch and 25 levels of melodic interval (all intervals within one octave of ending pitch). Subjects in experiment 1 rated how well the melodic fragment fit into the context example tonality. Ratings were three-dimensional: (1) pitch-interval interactions corresponding to a diatonic hierarchy, (2) perception of the dominant and tonic, and (3) perception of the three major diatonic triads. Subjects in experiment 2 sang their expected continuations to the melodic fragment. The continuations were influenced by factors similar to those of experiment 1. Continuation profiles could be reconstructed by multiplying corresponding entries from pitch and interval marginal mean profiles, implying that pitch and interval continuation production systems are functionally independent and produce a single response profile by means of a cross-correlational decision mechanism. Ratings and continuations can be explained by a harmonic mapping model, where the harmonics of a response tone map onto those of the tonic and the first tone of the fragment.
Dimensional tradeoffs in the perception of complex tone sequences
Authors: Singh Punita , Lauter Judith L. , Hirsh Ira J.
Published: October 2005

Rapidly occurring sequences comprising sounds that differ along some dimension can often be perceptually grouped into subsequences or “streams.” A study demonstrating the use of differences in timbre to provide a basis for stream segregation used four-tone sequences of the type: TxPx TyPx TxPy TyPy, where T and P refer to the timbre and pitch attributes of the complex tones. Forty-nine such sequences were constructed, with the first pair of tones having same pitch Px, but different timbres, and the second pair having pitch Py, and similarly differing timbres. The absolute position of the spectrum was varied to provide timbral “distances” between sounds, and relative spacing between harmonics varied to provide differences in pitch. Six listeners indicated their perceived grouping of the patterns, as being based on pitch, on timbral segregation, or ambiguous groupings not dominated by either cue. Results indicate that differences in spectra affecting either the timbre of the tones, or the pitch, or both, lead to tradeoffs between these attributes in determining the grouped percept and imply that the stream segregation phenomenon may therefore be based on spectral proximity of the sequential tones. [Work supported by NINCDS.]
Variability in frequency difference limens from newborn animals
Authors: Gray Lincoln , Rubel Edwin W.
Published: October 2005

Young chickens suppress their regular peeping when they hear a change in the frequency of a tone. Gray and Rubel [J. Acoust. Soc. Am. Suppl. 1 76, S13 (1984)] estimated frequency difference limens in newborn chickens using peep suppressions and a nonstandard adaptive procedure. The definition of a correct response depended on an initial series of control trials used to estimate the distribution of suppressions expected when there was no change in frequency. Consistent improvement in frequency difference limens, approximately 1% in 4 days, was observed. A more controlled procedure involves the presentation of a stimulus and a control trial in pairs. When the duration of suppression is greater on the stimulus than control trial then the response is defined as correct, and transformed up-down rules can be applied as usual. Unfortunately, the data from this procedure are inconsistent. Any increase in frequency selectivity over age is probably greater at high than low frequencies. Difference limens appear to be affected by intensity, but not by the direction of delta F nor temporal characteristics of the stimulus. In conclusion, high variability makes frequency difference limens difficult to estimate in neonates. [Work supported by NIH.]
Pitch change of a high-frequency harmonic complex following association with a low-frequency harmonic complex
Authors: Peters Robert W. , Hall Joseph W.
Published: October 2005

At a previous meeting [R. W. Peters and J. W. Hall, J. Acoust. Soc. Am. Suppl. 1 76, S76 (1984)] we reported an effect in which the pitches of “pitch shift” stimuli were changed in an adaptive learning paradigm. The present study extends the “pitch learning” results to stimuli which are more like those which actually occur in nature. Five observers made pitch matches for a high-frequency stimulus (1680, 1785, 1890 Hz; 16th, 17th, and 18th harmonics of F0 105 Hz) before and after simultaneous presentation of this stimulus with the first through fifth harmonics of 100 Hz (100, 200, 300, 400, 500 Hz). Data were collected for five nonconsecutive days. The results indicated that the pitch of the high-frequency stimulus changed from a pitch match near 105 Hz to a match near 100 Hz. Simultaneous presentation of the two complexes resulted in strong immediate adaptation effects for the high-frequency complex in that its pitch was shifted upwards. These effects disappeared when pitch of the high-frequency complex moved to near 100 Hz. The results will be discussed relative to pitch learning and adaptation models.
Sentence intonation in spontaneous utterances and fluently spoken text
Authors: Remez Robert E. , Rubin Philip E. , Ball Susan
Published: October 2005

What is the relationship between syntactic constituent structure and the intonation of a sentence? Psycholinguistic answers have varied, some viewing intonation as a close derivative of syntactic composition. The present study of this issue compared F0 and perceptual attributes of a number of syntactically and lexically identical sentence pairs. In each pair produced by a single talker, each sentence had the same pragmatic, thematic, and semantic function within a larger monologue of at least 40-s duration, but one member had been produced spontaneously, and the other was read from a text prepared from the spontaneous corpus. Our linguistic results of the comparison of two kinds of fluent speech are discussed in terms of intonation in reading and spontaneous speech, as well as in terms of the phonological control of intonation. Our perceptual results are discussed with respect to the listener's sensitivity to the spontaneous/read distinction, and the implications for the potential contribution of intonation to sentence perception.
Syllable boundaries and stress in speech segmentation
Authors: Cutler Anne , Norris Dennis
Published: October 2005

When a word is embedded in a nonsense matrix such that it belongs to two syllables of the matrix, detection of the word is inhibited when the second syllable is full but not when it is reduced: Thus melt is detected significantly faster in [mɛltə∫] than in [mɛltajv]. The effect is not determined by matrix or syllable length or by implicit morphological structure. Strictly left-to-right models of auditory word recognition predict no such difference because the embedded word should be detected as soon as it ends. Comprehension models which assume an obligatory syllabic level of representation also predict no difference since syllable boundaries occur at the same point in both matrices. The obtained result is, however, predicted by a language-universal model of continuous speech recognition proposed by the present authors, which emphasizes the importance of juncture detection. Applied to English, this model asserts that occurrence of a clear syllable boundary signals the onset of a full (stressed) syllable, which in turn implies an island of acoustic reliability and high phonetic yield, to which perceptual attention is diverted.
A metrical algorithm for lexical stress assignment in English
Authors: Williams B. J.
Published: October 2005

The correct placement of stress in an English word can dramatically affect the intelligibility of synthesized speech, and has often been seen as unpredictable. This paper describes a theory that aims to predict lexical stress by rule. The approach is based on the metrical theory of stress, and is set in the context of a text-to-speech synthesizer for (British) English. The technique uses modified prosodic stress feet together with a morphological analysis. A program has been written to implement the theory: The input is a broad phonemic transcription with boundaries for words, affixes of different types, and syllables, together with part of speech. The technique marks out the domain of stress assignment, and reduces phonemes to categories: consonant, liquid, long/short vowel, and reduced vowel. The stress foot units are then determined, by a monotonic parsing process taking account of syllable weight. These stress feet are linked together by rules conditioned by part of speech. The syllable bearing lexical stress is then marked, and certain segmental reductions carried out. The technique is being tested against a version of the LOB (Lancaster-Oslo/Bergen) corpus transcribed phonemically and marked for lexical stress. The aim of this theory is to model the strategy used by a native speaker in assigning a stress pattern to an unknown word.
Lipreading Cantonese with voice pitch
Authors: Ching Yuk Ching
Published: October 2005

The contribution of auditory voice pitch information to lipreading connected speech in Cantonese was evaluated by using a connected-discourse tracking task. Five lipreading conditions were used: with voice pitch, constant pitch, expanded pitch range, transposed pitch range, and no auditory input. Results indicate a consistent gain of 199% in lipreading proficiency when visual comprehension was complemented by voice pitch information. This will constitute an effective method of training and assessment in speech rehabilitative work with the deaf, especially in a tone language environment in which fundamental frequency patterning of speech is responsible for lexical distinctions.
Acoustic methods of microstructure characterization
Authors: Kline R. , Saghatchi H. , Hsiao C.
Published: October 2005

There has been a great deal of recent interest in using spectral analysis of backscattered ultrasonic signals to characterize material microstructure. As quantitative backscatter measurements can require signal averaging over several spatial orientations, a time consuming proposition, an alternative is needed. In this work the feasibility of using the spectral analysis of transmitted wideband signals was investigated. To precisely control grain size, samples were made by sintering glass beads of varying diameter. Porosity could be changed by altering the heat treatment of the samples. Results over the frequency range from 0.5–15 MHz are presented for specimens prepared with grain sizes ranging from 0.5–4 mm in diameter.
Anomalous polarization of elastic waves in transversely isotropic media
Authors: Schoenberg Michael , Helbig Klaus
Published: October 2005

The behavior of transversely isotropic elastic media is analyzed from both the kinematic (slowness surface) and dynamic (particle displacement) point of view. The relations for the slowness surfaces and wave front surfaces are derived in polar coordinates. Examination of the eigenvectors of the displacement equations of motion gives the relation for the polarization of the displacement vector associated with any plane wave. It is shown that the polarization of plane quasi-P and quasi-SV waves depends strongly on the sign of a particular elastic modulus, call it A, whereas the shape of the slowness surface is independent of the sign of A. When A is positive, which is the usual case, the particle displacement vector rotates in the same sense as the slowness vector. When A is negative, which is the “anomalous” case, the sense of rotation of the particle displacement vector is opposite to that of the slowness vector. Thus there is a direction in the medium for which the displacement vector associated with the quasi-P sheet of the slowness surface is perpendicular to the slowness vector and that associated with the quasi-SV sheet is parallel to the slowness vector. For both sheets the angle between the slowness vector and the displacement assumes all angles between 0 and π/2. This case even includes media that are “nearly” kinematically isotropic, i.e., characterized by spherical wave fronts emanating from point sources.