bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of the menstrual cycle on vibrotactile sensitivity
Authors: Gescheider George A. , Verrillo Ronald T.
Published: October 2005

Psychophysical thresholds for the detection of vibration delivered to the thenar eminence of the right hands of young males and females were measured every other day for 30–40 days. The frequency of the vibratory stimulus was either 15 or 250 Hz. The sinusoidal stimuli applied through a 3.0-cm2 contractor were 700 ms in duration and had rise-fall times of 25 ms. Stimulus amplitude was measured with a calibrated accelerometer mounted on the moving element of the vibrator. Data were plotted as a function of successive days in the menstrual cycle. Thresholds for the detection of the 15-Hz stimulus did not significantly change over the menstrual cycle. Thresholds for detecting the 250-Hz stimulus, on the other hand, varied significantly over the menstrual cycle. The 250-Hz threshold became progressively lower as subjects approached the onset of menstruation. After the onset of menstruation, the 250-Hz threshold gradually increased reaching a maximum value approximately 12 or 13 days later. Soon after the 12th or 13th day of the cycle, the threshold again began to decline and continued to decline until the onset of the next menstrual cycle. The thresholds of women taking birth control pills and men did not change systematically over the testing period.
Intensity coding in the auditory nerve
Authors: McGee JoAnn , Walsh Edward J.
Published: October 2005

The mechanisms by which intensity is coded in the discharges of single auditory nerve fibers have not been fully determined, although hypotheses involving changes in discharge rate fiber recruitment have been proposed. In this paper, we will review the characteristics of auditory nerve fiber responses that may code for loudness growth and intensity discrimination. Psychophysical dynamic ranges, which are in excess of 100 dB, cannot be accounted for by the 30–40 dB dynamic range displayed by the majority of individual auditory nerve fibers. Recently, however, a subpopulation of auditory nerve fibers has been identified within each characteristic frequency (CF) region. The characteristics of these fibers include low spontaneous activities, a wide range (greater than 70 dB) of thresholds, high sensitivities to changes in intensity (i.e., steep rate-intensity functions), and dynamic ranges as high as 60–70 dB. These results indicate that the responses of fibers having similar CFs and spanning the normal range of thresholds may account for a large portion of the behavioral dynamic range. Furthermore, intensity discrimination experiments designed to limit the spread of excitation (Hellman, 1974; Viemeister, 1974), suggest that intensity coding does not depend on recruitment of neighboring fibers. Finally, phase-locking exists for stimulus frequencies below 5 kHz, and phase-locking thresholds are on the average 15 dB lower than corresponding discharge rate thresholds. Thus, the overall dynamic range associated with auditory nerve responses can account for nearly the entire psychophysical loudness range. Other characteristics of neuronal response, such as input/output nonmonotonicities and synchrony suppression in the coding of multi-component stimuli, will be discussed.
Simulation of the impulse response between a single source and multiple, closely-spaced receivers in a reverberant room
Authors: Peterson Patrick M.
Published: October 2005

In considering the design of multimicrophone hearing aids, it would be useful to have a simulation of the effect of a reverberant room on the acoustic signals received at closely spaced microphones. The image method, as described by Allen and Berkley [J. Acoust. Soc. Am. 65, 94–950 (1979)], can be used for this purpose, but faithful simulation of intermicrophone phase requires a modification of the algorithm. Specifically, rather than quantize impulse arrival times, an analytic low-pass time function is used to extrapolate the effect of an impulse arrival to nearby sampling times. While Allen and Berkley's original method gives rise to errors in arrival time of up to one-half the sampling interval, the modified method approaches zero error. The low-pass time function can be viewed as the impulse response of a low pass anti-aliasing filter. The choice of this filter is governed by considerations of computation time, the phase added by the filter, and filter cutoff characteristics. [Work supported by NIH.]
Rare-earth magnetostrictive transducer materials
Authors: Clark A. E. , Savage H. T.
Published: October 2005

Within the last decade, a new class of magnetostrictive materials, which offers substantially improved high power transduction, has emerged. These materials are alloys of iron with rare-earth elements, such as terbium and dysprosium. Previously, all highly magnetostrictive materials (Δ/t>10−3) required cryogenic refrigeration, forcing high-power transducer designers to rely almost exclusively upon piezoelectric ceramics. In effect, the ruggedness and reliability of magnetostrictive metals have been sacrificed for the high power and high efficiency of piezoeceramics. However, within the last few years, high-power underwater transducers have been constructed using rare-earth alloys (Raytheon, Portsmouth, RI, and Gould, Glen Burnie, MD). In this presentation, the magnetic and magnetoelastic properties of various important rare-earth-iron alloys will be compared with each other and to earlier magnetostrictive materials. Stoichiometry and crystal defects affect the magnetization process and thus play major roles in transducer performance. Magnetostriction and hysteresis curves will be presented for rare-earth-Fe2 alloys over the range of compressive loads useful in transducer design. Low-temperature limitations, as well as transduction at high temperature (> 200°C), will be discussed.
Piezoelectric thin film ZnO on Si integrated microphone
Authors: Royer M. , Holmen J. O. , Wurm M. A. , Glenn M.
Published: October 2005

Recent technology advances in thin film deposition and in fabrication of Si microstructures have made possible the development of a new class of “intelligent” sensors having electronics and sensing element integrated on the same Si chip. The present paper describes a fully integrated microphone which combines high sensitivity, wide frequency range, low power, and low cost of batch processed miniature silicon components. A thin piezoelectric layer of ZnO transforms the mechanical deflection of a thin Si diaphragm into a piezoelectric output voltage. This signal is directly connected to an amplifier built on the same chip. A unique annular electrode design provides cancellation of temperature induced parasitic signal due to the pyroelectric effect in ZnO. Integrated devices were fabricated and tested. Measured performances were: sensitivity of 25 μV/μbar, a signal to noise ratio of 5:1 at 2 μbars, a frequency response of 0.1 Hz to 10 kHz and a power consumption below 40 μW. Further improvements in the onchip electronics should increase the signal to noise ratio by an order of magnitude bringing its value in the range of the conventional hearing aid devices.
Rare-earth flextensional transducer
Authors: Kuhn Philip M.
Published: October 2005

The grain-oriented rare-earth iron alloy, Trefonol D (Tb0.3 Dy0.7 Fe1.95), exhibits exceptionally high magnetostrictive strain capability. Using the flextensional shell to couple the rare-earth rod motion to the water medium, very high acoustic source levels may be achieved compared to a piezoelectric driven flextensional transducer. Also, due to the lower elastic modulus of Terfenol D, a smaller transducer results for a given frequency. A source level of 200 dB re: 1 μPa at 1 m was achieved at 1350 Hz for an experimental transducer having the shell dimensions of 6.8 in. × 6 in. × 3.1 in. Future flextensional transducers, using the rare earth alloy, will incorporate improvements that will reduce losses due to eddy currents and provide depth compensation.
Magnetostrictive metallic glassy ribbon gradient hydrophone
Authors: Benjamin Kim C.
Published: October 2005

The development of a directional low-frequency gradient hydrophone which utilizes the magnetostrictive Metglas alloy (2605SC) is presented. The Metglas ribbon was transversely annealed in a magnetic field which raises the magnetomechanical coupling factor above 0.90. The Metglas ribbon was laminated to a slightly thicker stainless steel strip, and the bilaminate was mounted within a neutrally buoyant housing in a cantilivered configuration. Three Metglas/stainless steel thicknesses were examined, 25.4/38.1, 50.8/76.2, and 101.6/127.0, where all dimensions are in micrometers. Measured results indicated that the hydrophone sensitivity is largely affected by the Metglas thickness, cross-sectional area, and number of turns in the pickup coils. The hydrophone had a dipole directionality which was due to the ribbon geometry of the active element.
Space shuttle Orbiter crew compartment acoustic noise environments and control considerations
Authors: Hill Robert E.
Published: October 2005

The acoustic noise environment present in the shuttle Orbiter crew compartment during orbital operations has been measured and the contribution of the various equipment noise sources has been determined. While on orbit, the shuttle astronaut crews perform their functions in a shirt-sleeve environment without the use of any personal noise attenuation devices. Thus noise from the avionics and environmental and life support systems becomes an important factor influencing verbal communication, sleep, and crew comfort. A noise plan was established during the Orbiter design phase to define the middeck and flight deck noise environments. Estimates of these environments were made for each of the noise generating devices, as well as the combined noise spectrum. Subsequent noise surveys, performed in Columbia prior to the first flight, were used to verify and/or update the estimates and point out possible problem areas. The results of these surveys will be presented in detail. Equipment noise levels observed to be excessive were identified, and appropriate noise reduction methods were applied. The results of this work will be included in a discussion on noise control methods for spacecraft systems. In-flight noise data, acquired by the astronauts using a handheld sound level meter, will also be presented.
Human response to vibroacoustic environments of space vehicles
Authors: Willshire Kelli F.
Published: October 2005

To insure efficient utilization of the system, space station design and operations will require special habitability considerations for the occupants and crew because of the relatively long duration missions. Of particular concern is the environment in which the personnel will live and work, and how it affects both the performance and comfort of the occupants. Current criteria do not consider possible effects of reduced gravity, long duration, and confinement. Preliminary to developing space station vibroacoustic habitability criteria, the adequacy of criteria for other space vehicles has been reviewed. In this paper, specific responses to the noise and vibration environments of both Skylab and Shuttle will be discussed. Some astronauts have reported sleep interference, communication interference, distraction, and general annoyance as noise related complaints. In addition, information from the Russian Salyut missions, as well as similar earth based situations (e.g., submarines, remote military outposts), will be reviewed.
Sonic boom measurement for space shuttle
Authors: Stanley John F.
Published: October 2005

Sonic boom measurements have been obtained during six flights of the Space Transportation System (STS). Information regarding sonic boom signature characteristics that include overpressure, period, and shock-rise-time will be discussed and some comparisons with predictions will be shown. Measurements of the sonic boom generated by the orbiter during descent flight phases were made on STS-1, STS-2, STS-4, and STS-11. Ascent measurements were obtained during STS-5 and STS-7 launches. The objectives were (1) to define sonic boom characteristics of the STS during both launch and entry, and (2) to assess the validity of a semi-empirical method used previously to predict 2, 4, and 11 entries into Edwards Air Force Base or Kennedy Space Center. Sonic booms during descent are of particular interest to NASA because of the population centers exposed. During ascent from the Kennedy, no land masses are impacted by the pressure wave. However, ascent booms for STS launches are important to the Air Force because of their plan to launch the Shuttle from Vandenberg Air Force Base. From Vandenberg, the launch boom may impact (for some launch azimuths) the Channel Islands and, under some conditions, the California coast itself.
An investigation of air inlet designs for anechoic chambers requiring high-volume subsonic flows
Authors: Quartararo Louis R. , Lauchle G. C.
Published: October 2005

Slotted or porous air-inlet walls may be used in an anechoic chamber to provide a relatively steady and nonrotational inflow to an air-moving device undergoing acoustical tests. A study was conducted to determine the effect of variations in slotted-inlet-wall designs on a chamber's aerodynamic performance. The experimental investigation was carried out using a one-sixth-scale model of a proposed test facility. Axial turbulence intensities and steady-state spacial disturbances were measured in the plane of a proposed test fan rotor, for different slotted-inlet and anechoic-wedge configurations. These measurements were made using a hot-wire anemometer and a five-hole-probe rake. This paper discusses the design and performance of selected model-scale slotted-inlet walls, and gives guidance for the design of full scale slotted-inlet and anechoic-wedge configurations. [Work supported by The Applied Research Laboratory, The Pennsylvania State University, under contract with NAVSEA.]
Effects of auditory maskers on whistling and voicing
Authors: Burzynski Cecile M. , Abbas Paul J. , Amazi Deborah K. , Zimmermann Gerald N.
Published: October 2005

The effects of high-intensity auditory maskers on whistling and voicing pitch matching tasks were studied. Subjects whistled or produced the vowel /ah/ to match the frequency of a target tone. Nine experimental masking conditions were presented randomly: no masker, white noise, a pure tone at the target frequency, three tones above and three tones below the target frequency. Masker tones were presented at either 80 or 100 dB SPL. Mean fundamental frequency of voicing was essentially unaffected by auditory manipulations, i.e., productions obtained during masking conditions were no different than productions in quiet. For whistling, mean fundamental frequency of production appeared to be differentially affected by masker frequency. Masker frequencies lower than the target generally resulted in higher frequency of production. Similar effects were observed for both levels of masking stimuli which argues against an interpretation of the observed effects in terms of a peripheral masking of the production. Rather, we would suggest that the results are consistent with a hypothesis that the behaviors involved in the whistling and voicing tasks are differentially affected by auditory information. [Work supported by NIH Grant 07555.]
Tracheostomal occlusion and the Blom-Singer device: rehabilitative issues
Authors: Blakley Brian , Podraza Bonnie
Published: October 2005

The Blom-Singer voice prosthesis and tracheostomal valve for voice restoration following laryngectomy promised improved communication ease, quality, and flexibility over traditional esophageal speech. Increased use of T-E puncture at time of laryngectomy, effectively precludes learning standard esophageal speech, even for patients holding promise of speech independent of prosthetic devices. The assumption is that the B-S prosthesis with the T-S valve is superior to esophageal speech because: (1) speech becomes lung powered, (2) hand manipulation is unneeded, and (3) voice quality is more “normal.” This present study investigated (1) phonation onset latency, (2) intercostal muscle mistiming of syllables, (3) intensity of voice, and (4) phonetic accuracy of initial consonants in connected speech in two speech production modes (B-S plus T-S valve versus B-S plus manual occlusion of stoma) in one patient who underwent total laryngectomy with B-S and T-S valve placement. The investigation suggested (1) there is phonation latency with T-S valve use, (2) latency affects syllable timing of initial consonant production, (3) voice intensity is greater with manual occlusion than with T-S use, and (4) phonetic accuracy is enhanced in the manual occlusion mode as opposed to the T-S mode. T-S valve use was associated with a sacrifice of voice quality and loudness suggesting that laryngectomy patients be allowed a six-month period to learn traditional esophageal speech before a T-E puncture is made and the B-S apparatus is utilized.
Hearing loss simulation: A comparison of two methods
Authors: Fabry David A. , Tasell Dianne J. Van
Published: October 2005

Hearing threshold configuration of the impaired ear was simulated, via two different methods, in the normal ear of each of six subjects with unilateral sensorineural hearing loss. The simulation methods were (1) frequency-specific attenuation (filtering), and (2) masking by shaped masking noise. Identification responses to 20 consonant-vowel nonsense syllables were obtained from the normal ear of each subject in both hearing loss simulation conditions, as well as from the impaired ear. Data were scored both for percent correct syllable recognition and for errors on a set of eight consonant features. Overall performance level and consonant feature error patterns appeared to be relatively independent measures of speech recognition. For three subjects, both masking and filtering successfully simulated the effects of sensorineural hearing loss on consonant feature error patterns. For the remaining subjects, one or both of the simulation schemes was inadequate. [Supported by NINCDS Grant NS-12125.]
Tone perception, phoneme perception, and speech perception in hearing-impaired subjects
Authors: Dreschler W. A. , Plomp R.
Published: October 2005

The results of 21 sensorineurally hearing-impaired subjects on an extensive battery of tone-perception, phoneme-perception, and speech-perception tests are presented. Test on loudness perception, frequency selectivity, and temporal resolution at test frequencies of 500, 1000, and 2000 Hz were included. The mean values and the gradient across frequencies have been evaluated. Phoneme-perception data were gathered by means of (dis)similarity judgments and phonemic confusions. Speech-reception thresholds were determined in quiet and in noise, and with additional low-pass and high-pass filtering. The results show that hearing loss for speech is related to both the frequency resolving power and to the temporal processing by the ear. For the noise conditions the 2000-Hz parameters are the most important ones, whereas for the quiet conditions the lower frequencies are more important. Phoneme-perception parameters proved to be more related to the filtered-speech thresholds than to the thresholds for unfiltered speech. This finding may indicate that phoneme-perception parameters play only a secondary role, and for that reason their bridging function between tone perception and speech perception is only limited.
Speech-reception thresholds in noise with one and two hearing aids
Authors: Festen J. M.
Published: October 2005

Binaural, free-field, speech-reception thresholds (SRTs) in 70-dBA noise were measured with conversational sentences for 24 hearing-impaired subjects without a hearing aid, with a hearing aid at the right or at the left ear, and with two hearing aids. The sentences were presented in front of the listeners and interfering noise was presented either frontally or laterally. Subjects used their own binaural behind-the-ear hearing aids and adjusted the gain(s) for optimum intelligibility in 70-dBA noise. Subjects had nearly symmetrical hearing losses with an average over 500, 1000, and 2000 Hz of between 30 and 65 dB. For hearing losses below 50 dB the SRT in both ears was determined by the S/N ratio even when only one hearing aid is used with the unaided ear at the shadow side of the head. It appears that, just as for monaural hearing aids, a second hearing aid generally does not improve the SRT under conditions with a high noise level. However, for situations with a low noise level or a high absolute threshold, in which a monaural hearing aid is profitable, a binaural aid is even more profitable.
Speechreading supplemented with frequency-selective sound-pressure information and formant-frequency information
Authors: Breeuwer M. , Festen J. M.
Published: October 2005

The benefit of supplementing speechreading with frequency-selective sound-pressure information or formant-frequency information was studied by auditorily presenting this information to normal-hearing listeners without experience in speechreading. In a first experiment the sound-pressure levels in one or two, octave or 1/3-octave bands were used to amplitude-modulate pure-tone carriers with frequencies equal to the center frequencies of the filterbands (500, 1600, or 3160 Hz). Eighteen listeners scored 65.7% correct syllables (from totally unknown sentences) for speechreading with sound-pressure information in a single one-octave band at 500 Hz, and 86.7% correct syllables for speechreading with two one-octave bands at 500 and 3160 Hz, respectively. Speechreading-only scored 22.8%. In a second experiment the frequencies of the first and second formant from voiced speech were presented either as pure tones, or as a complex speechlike signal. In this experiment 18 (other) listeners scored 82.0% correct syllables on speechreading with formant-frequency information. No significant difference was found between presenting this information as pure tones or as a complex speechlike signal. Speechreading-only scored again 22.8% correct syllables.
Effect of phase compensation and damping on the open loop transfer function of a vented hearing aid worn in situ
Authors: Preves David A.
Published: October 2005

An in-the-ear hearing aid having 120-dB peak SPL, 50-dB peak gain, and a 3-mm-diam vent mounted on Kemar was treated as a feedback control system. The feedback loop was broken between microphone and amplifier to obtain the magnitude and phase of the open loop transfer function and hence the proximity of the fitting to onset of acoustical feedback oscillation. With the loop closed, as the gain control was adjusted, the hearing aid generally oscillated if the open loop magnitude exceeded 0 dB. The frequency of acoustic feedback oscillation correlated fairly well to the frequency at which the open loop magnitude crossed 0 dB with gain decreasing. The same measurements were repeated with a phase compensator added between the hearing aid microphone and amplifier and with an acoustic resistance damper added in the tubing of the hearing aid receiver. Both the phase compensator and damper improved phase margin and hence rendered the hearing aid fitting less likely to oscillate.
Diagnostic profiles obtained from a psychoacoustic assessment procedure with mathematically impaired subjects
Authors: DeFosse Carlton O. , Shirk George B.
Published: October 2005

A three-phase assessment paradigm was implemented to identify possible areas of dysfunction in auditory visual perception and processing by mathematically impaired subjects. Phase I involved assessing peripheral auditory acuity, Phase II tested central auditory processing, and Phase III evaluated cortical integration of auditory and visual sensory information. Several diagnostically significant profiles emerged from the test data, and will be discussed in regard to relevance in designing successful mathematical training programs for the mathematically impaired population. The profiles will be presented and discussed as to clinical and educational repercussions.
Acoustic cavitation nucleation and stabilization mechanisms
Authors: Atchley Anthony A. , Crum Lawrence A.
Published: October 2005

With the growing concern that there may be some biological effects associated with cavitation produced by high intensity ultrasound, it is important to constantly reexamine the nucleation and stabilization mechanisms that give rise to cavitation. Further it is reasonable to expect that these mechanisms should be very similar whether one observes cavitation in a physical system or in vivo. A brief review of the mechanisms will be presented along with some recent advances, both theoretical and experimental, that may shed additional light on the topic. [Work supported in part by the NSF.]
Slow relaxations in sea water: T-jump measurements
Authors: Mellen R. H. , Mallo P. , Waton S. , Candau S. J.
Published: October 2005

Sound absorption in sea water involves chemical equilibria with rather slow relaxation rates. The low-frequency range of the resonator method is limited by practical considerations of size and experimental conditions must usually be altered to place the relaxation frequency within the measurement window. For relaxations involving acids or bases, the temperature-jump pH method permits rate measurements below a limit set by indicator response (∼ 105/s). Recent T-jump studies confirm unambiguously that the low-frequency (∼ 1 kHz) relaxation mechanism in sea water is an acid-base exchange between boric acid and carbonate [P. Mallo et al., J. Phys. Chem. (in press) (1984)]. Further investigations of the boric acid exchange in similar Lewis systems, e.g., ammonia, reveal single relaxations with comparable rates. The magnesium carbonate ion-pair equilibrium—a minor component of sea water absorption at mid-frequencies (∼ 10 kHz)—shows more complex behavior with several identifiable relaxations in the measurement range. The magnesium sulfate relaxation (∼ 100 kHz) is unsuited to the method because of both speed and lack of pH dependence. Visiting scientist; home address: 117 Boston Post Road, Old Lyme, CT 06320.
Coupling of airborne sound into the porous elastic earth
Authors: Sabatier James M. , Bass Henry E. , Bolen Lee N.
Published: October 2005

The Earth's surface was modeled as a two-dimensional porous elastic medium overlaying a semi-infinite nonporous elastic medium. The steady-state acoustic and seismic transfer functions for the surface have been measured and will be compared to the predicted functions using the Biot-Stoll model for wave propagation in a porous elastic medium. The acoustic and seismic transfer functions have been taken as the ratio of the acoustic and seismic response below the surface to the acoustic response above the surface, respectively. These functions were measured using a probe microphone and a geophone. The transfer functions were predicted from a plane wave analysis of the Biot-Stoll model and include shear waves in both elastic media. The surface impedance was also predicted and will be compared to an empirical impedance determined from the measured flow resistivity. [Work supported by ARO.]
Measurement of the variation in γ of air with humidity
Authors: Wong G. S. K. , Embleton T. F. W.
Published: October 2005

The theoretical values on the variation in the specific heat ratio γ of air with relative humidity is verified experimentally with a direct acoustical method: two condenser microphones are coupled together in a cavity. One microphone is driven as a sound source and the other operates as a receiver. Standard air mixtures with various degrees of humidity were fed into the cavity. The pressure of the cavity was maintained constant at 1 atm with an absolute piston gauge, and the selected temperature was achieved with a constant-temperature circulating bath. By measuring precisely the relatively small changes in the ratio of voltage e1, which is derived from the driving current of the driver microphone, to voltage e2 from the receiving microphone, one is able to deduce the variation in γ with humidity. The theory and the experimental procedure are discussed in detail. The results obtained were in good agreement with the theoretical values given by the authors in a previous presentation [J. Acoust. Soc. Am. Suppl. 1 75, S17 (1984)].
Modeling scatterers embedded in plane-layered media by a hybrid Haskell-Thompson and boundary integral equation method
Authors: Schuster Gerard T. , Smith Lance
Published: October 2005

A hybrid Haskell-Thompson and Boundary Integral Equation (BIE) method is formulated which can model the acoustic and elastic response of scatterers embedded in plane-layered media. The scatterers can have an arbitrary smooth shape but must not intersect layer interfaces. The Green's function of the scatterer is computed by BIEs in the (x, z, w) domain and the Green's functions of the layers is computed by a Haskell-Thompson method in the (kx, z, w) domain. Their fields are coupled by the appropriate combination of FFTs and extrapolation operators and are finally summed up in a Born series. For notational convenience this hybrid method will be called a Generalized Born Series (GBS) method. Two advantages of the GBS method are (1) it is more efficient than finite elements or finite differences for small scatterers embedded in thickly layered media; and (2) no artificial side reflections are generated from the infinitely extended plane interfaces. The disadvantages are (1) the convergence rate of the GBS depends on the model and is unknown a priori; and (2) the computation time increases with the size of the scatterer. [Work supported by MIDAS, a consortium of oil and geophysical companies.]
Acoustic scattering from Arctic sea-ice ridge keels with high angle PE
Authors: Greene Robert R.
Published: October 2005

Observed transmission loss levels in the Arctic can be reproduced in HAPE simulations by scattering from trapezoidal ridges with random keel depths of Rayleigh distribution. Random depth ridges produce more loss than constant depth ridges of the same mean depth. This suggests the scattering process is dominated by the largest ridges. At short ranges, the signal is slightly enhanced by bottom-bounce paths. High Angle PE (HAPE) is a large scale finite difference solution of a PE-type one-way wave equation with a wide angle approximation. Advanced features include direct simulation of scattering from variable depth interfaces and a high-speed implementation exploiting vectorized processing techniques.
Vibration exposure of heavy equipment operators in paperboard manufacturing
Authors: Wasserman D. E. , Erdreich J. , Wilcox T. , Doyle T. , Spaeth S.
Published: October 2005

A health hazard evaluation of a group of 12 heavy equipment operators involved in paperboard products manufacturing was requested of NIOSH. Four operators use the equipment regularly and eight operators use it occasionally. Three of the four regular operators and two out of eight occasional operators have complained of recurrent episodes of prostatitis. Of the five complainants, four reported that their symptoms were commonly exacerbated after operating the equipment for several days. To devise a solution for this problem, we first measured three-axis vibration at the floor and top of the seat during typical work cycles. From these measurements we calculated vibration spectrum, crest factors for specific parts of the work cycle, and seat transmissibility. This paper will describe the multi-axis vibration characteristics of the vehicles used by these workers, and we will discuss the potential for vibration exacerbated pathology, and methods for its reduction.
Sequential effects in a clinical sample
Authors: Matthies M. L.
Published: October 2005

Sequential dependencies refer to the influence of a previous trial (or trials) on the response to the current trial. Sequential effects can depress P(C) and may be more likely to occur where difficult discriminations and/or inexperienced subjects are involved. The specific sequential dependency considered here is the clustering of incorrect responses. A first-order, sample autocorrelation as used by Shipley [J. Acoust. Soc. Am. 33, 1142–43 (1961)] formed the basis of a Chi-square analysis for the significance of sequential effects. One normal-hearing young adult, two young adults with hearing loss, and four hearing-impaired persons over 55 years of age served as subjects in a frequency-discrimination task. The eight signals used with the subjects included pure tones, ratio-bandwidth (20%), and fixed-bandwidth (400 Hz) narrow-band noise at 500, 2000, and 5000 Hz. Patterns of clustering of incorrect responses were analyzed as a function of subject age and hearing status as well as their relation to P(C) and experience with the discrimination task. [Work supported by NIH.]
Cochlear effects of two new loop diuretics
Authors: Rybak Leonard P. , Whitworth Craig
Published: October 2005

Loop diuretics such as ethacrynic acid and furosemide have been shown in previous studies to alter cochlear function in animals and humans. Since the endocochlear potential of animals is reduced after administration of other loop diuretics, we have studied the effects of two newer loop diuretics, ozolinone and indacrinone, on this d.c. resting potential. Chinchillas weighing 400–600 g were anesthetized with pentobarbital 30 mg/kg and ketamine 45 mg/kg intramuscularly. The bulla was opened and the endocochlear potential (EP) was measured with a glass microelectrode placed through the round window. Control animals injected IV with vehicle had very little change of the EP. Doses of the diuretics ranging from 50–300 mg/kg were injected intravenously. Ozolinone had very little effect on the EP even at the highest dosage. On the other hand, indacrinone injection caused a dose-dependent reduction of the endocochlear potential. It was interesting to note that the maximum effect of indacrinone did not occur until 20–30 min after injection. These findings suggest that the newer loop diuretics may act on the cochlea in a different manner. Some of these differences may be due to discrete mechanisms of drug distribution and metabolism. [Work supported by NIH.]
A spectral contrast illusion
Authors: Deutsch Diana , Moore F. Richard
Published: October 2005

A new illusion is described, produced by presenting two repeating sequences of Shepard tones, one to each ear. Each tone consisted of several sinusoidal components separated by octaves, and the tones were generated under various fixed spectral amplitude envelopes. The pitches were as in the scale illusion [D. Deutsch, J. Acoust. Soc. Am. 57, 1156–1160 (1975)], omitting those standing in octave relation. Thus B-E-G-G-E-B was presented to one ear, while D-A-F-F-A-D was presented to the other ear. Musically trained subjects notated separately the sequences that they heard in each ear. Most subjects reorganized the tones in accordance with pitch proximity, so that they obtained the illusion of B-A-G-G-A-B in one ear, together with D-E-F-F-E-D in the other ear. The apparent locations of the two sequences were often independent of the positioning of the earphones. Further, the subjects generally reported the two sequences as in different octaves. Analogous effects were obtained with binaural presentation of simultaneously ascending and descending Risset glides. [Work supported by NIMH.]
Applications of the parametric source to high resolution volume, bottom, and sub-bottom profiling
Authors: Konrad William L. , Carlton Lynn F.
Published: October 2005

The usefulness of the parametric source for the depiction and measurement of volume scatterers in several ocean locations is demonstrated by vertical profiles. Bottom and sub-bottom profiles in both shallow and deep water reveal the capability of the parametric source for achieving high resolution and modest bottom penetration measurements. The design of a source capable of bottom penetrations in the order of 1000 m is considered to illustrate the size and power requirements of such a sonar.
Sea surface forward scatter and reverberation measurements using parametric arrays
Authors: Roderick W. I.
Published: October 2005

Several underwater acoustic experiments, which included the measurement of both surface forward and backscatter, have been conducted with parametric arrays in adverse shallow water environments. The broad bandwidth and narrow beamwidth capabilities of the array have been effectively utilized in overcoming the multipath contamination problems inherent to shallow water environments. The unique combination of the parametric array and signal waveform design/processing have permitted the measurement of surface scattering properties such as low grazing angle specular surface loss, Doppler spreads and shifts of forward and backscatter, surface scattering strength, and other statistical properties of surface scatter. Acoustic inversion techniques have also led to knowledge of the ocean surface characteristics. This paper will highlight measurement techniques, parametric array advantages and pitfalls, and experimental results obtained with difference frequencies that ranged from 2 to 30 kHz, and grazing angles from about 1° to normal incidence. [Work supported by NAVSEA 63R.]
Assessment of random logitudinal and lateral vibration on human body fatigue using a physiological approach
Authors: Demic Miroslav
Published: October 2005

Lateral and logitudinal mechanical oscillations occuring during the use of transportation means, constructional machines, and other similar means influence human body fatigue. As a rule, they have random character. Former investigations in this field were mainly based on determination of human body behavior under the influence of harmonic oscillations. Recent studies indicate that man is more 1.5(2)–10(Hz) in the range of sensitive to random oscillations. In this paper an effort is made to define recommendations for estimating random logitudinal and lateral 0.2–30(Hz) oscillations. It was done by examining the human head acceleration when walking, first. Those accelerations were divided with corresponding transfer head-seat function and the curve characteristics were found. On the base of literature data, the ratios between effective value of random logitudinal oscillatory accelerations and time interval up to the occurrence of human body fatigue were defined which enabled plotting of the curves of equal fatigue for logitudinal directions. On the basis of theoretical ratios existing between the lateral and logitudinal accelerations while walking, the corresponding curves of equal fatigue for lateral direction were defined.
The perceptual centers of alliterative monosyllables
Authors: Smith M. R. , Fowler C. A.
Published: October 2005

There are systematic deviations in acoustic measurements of the syllable onsets of perceptually isochronous rhyming monosyllables differing in initial consonant structure [C. Fowler and L. Tassinary, Atten. Perform. IX, 521–535 (1981)]. In the present study we examine the corresponding intervals of monosyllables that differ in (1) vocalic nucleus or (2) coda. Metronome-timed tokens of both alliterative and homophonous sequences were measured from the productions of two talkers. The observed intervals between syllable onsets and those between vocalic onsets show a pattern consistent with the hypothesis that talkers and listeners are sensitive to a syllable-internal event, perhaps the articulatory onsets of the vowels. [Work supported by NICHHD.]
Scaling analysis of consonant confusion matrices: An acoustic account
Authors: Yuchtman Moshe , Bilger Robert C.
Published: October 2005

Multidimensional scaling analysis of consonant confusion matrices has been frequently used as a means to derive the underlying perceptual representation of speech sounds. In many studies, dimensions yielded by such analyses have been interpreted in terms of binary or tertiary linguistic features. The results of these studies, however, have not converged to a single system of perceptual features. Soli and Arabic [J. Acoust. Soc. Am. 66, 46–59 (1979)], argued that an acoustic- rather than a feature-based interpretation may provide a better account of multidimensional scaling solutions. The current study was undertaken to explore further the adequacy of such an interpretation by providing a quantitative description of the relations of acoustic properties of consonants to their respective projections on dimensions yielded by multidimensional scaling analysis. The material for acoustic and statistical analyses consisted of the speech stimuli and confusion matrices of Wang and Bilger [J. Acoust. Soc. Am. 54, 1248–1266 (1973)]. Stimuli included 24 CV and 19 VC syllables, the vowels being either /i/, /a/, or /u/. For each syllable, acoustic analysis yielded an ensemble of spectral, durational, and energy measures. Consonant confusion matrices were analyzed using the SINDSCL procedure. The results of regression analyses of the acoustic parameters and the perceptual dimensions obtained by the scaling analyses will be discussed in terms of their implications for an acoustic model of consonant confusions. [Work supported by NIH.]
A method of localization and identification of a solid elastic cylinder
Authors: Luppé F. , Quentin G.
Published: October 2005

A cylinder is immersed in water and insonified at large ka (k = wave-number, a = radius of the target) in the backscattering geometry. We describe a method for determining the distance of the transducer to the target, the radius of the cylinder, and the material of the cylinder from ultrasonic mesurements. The measured arrival times of four received echoes provide us a way of approximating the distance, the radius, and the velocities of the bulk waves in the solid. We present a formula that gives the maximum of the measurement error allowing a degree of accuracy on the estimated values of the velocities that is compatible to the proper identification of the material of the cylinder. In those eases when the value of this maximal measurement error would be too little to be realistic, we evaluate the density of the solid from the measurement of the amplitudes of two different echoes.
Axially focused (glory) scattering due to surface waves generated on tungsten carbide spheres
Authors: Williams Kevin L. , Marston Philip L.
Published: October 2005

When a short tone burst is incident on a tungsten carbide sphere in water, the backscattering response shows a decaying pulse train [L. R. Dragonette, S. K. Numrich, and L. J. Frank, J. Acoust. Soc. Am. 69, 1186–1189 (1981)] which can be attributed to a specular reflection and repeated circumnavigations of waves. We have experimentally investigated the angular dependence of Rayleigh wave contributions as the receiver is moved away from the backscattering axis. It was found that this angular dependence can be approximately modeled by J0(βγ), where β depends on the frequency of the sinusoidal tone burst used (or equivalently the ka of the sphere) and γ measures the angle relative to the backscattering axis. This form of angular dependence may be attributed to a weak axial focusing along the backward direction. We have used scattering theory along with an asymptotic expansion of the Legendre polynomials to obtain a prediction of how β will vary with ka. Experimental results in the range 30 ⩽ ka ⩽ 100 are compared with theory. [Work supported by ONR.]
A numerical approach to the solution of the acoustic inverse scattering problem
Authors: Delsanto P. P. , Alemar J. D. , Rosario E. , Nagl A. , Überall H.
Published: October 2005

In the scattering of acoustic waves from a solid or fluid obstacle, the spectral response contains, in principle, complete information about the scatterer. This information is, however, hidden in an often irregular and intricate array of peaks and valleys. The resonance scattering theory can be an optimal tool for disentangling the spectral response structure, through a partial wave analysis and a separation of the internal resonances from the external resonances and/or background. In an easy, step-by-step approach we show how the size, orientation, and nature of an infinite cylindrical scatterer can be predicted from the experimental spectral response. Only one mode and a limited frequency range are sufficient for our analysis, which is very important, especially when the partial wave analysis of the experimental spectral response or the separation between external and internal resonances cannot be easily accomplished. An approach for the prediction of the scatterer shape is also suggested. [Work supported by U.S.A. R. O. Grant ♯DAAG29-81-G0016.]
Teaching foreign pronunciation
Authors: Thomas R.
Published: October 2005

Acoustical analysis may be used to teach foreign pronunciations provided that previous research has determined (1) what aspects of the learner's language and of the language he wants to learn are significant both from the acoustical point of view, and to the speakers of both languages and (2) which of these aspects are easily modified by all speakers of the learner's mother tongue and cause the modification of most, and if possible, all other crucial points. Common knowledge of (1) and (2) above is vast but made of incoherent, and at times doubtful, items. We continued P. Delattre's work on the subject for the English and French languages, and we currently obtain nearly 100% success in rapidly teaching any of those two pronunciations to speakers of the other language (Patent No. FR 80 02 899). Of course the research work has to be done all over again when one of the two languages is changed, but there are indications that only a few basic elements are used in all the human languages we have heard spoken by native speakers (about 50) and linguistic reports seem to encourage generalization. Though ascertaining what these elements are (our current division of syllables into vowels and consonants is not useless for that) will not solve the basic semantic problems of languages, it will (1) make the study of any foreign pronunciation both efficient and inexpensive and (2) greatly contribute to (a) mechanical translation of visual into acoustical presentations of languages, and vice versa, and (b) mechanical recognition of human voices and speech.
Masking-level differences for three-component complexes
Authors: Dye Raymond H. , Yost William A.
Published: October 2005

The detectability of three-component complexes was measured as a function of the number of interaurally phase-reversed components, which components were phase-reversed, and the frequency spacing between the components. The center frequency of the complex was always 750 Hz, and the frequency spacing (Δ f) was 20, 50, 100, or 250 Hz. The duration of the signal was 100 ms. All signals were presented against a continuous lowpass noise (2.5-kHz cutoff frequency) whose noise-power per unit bandwidth was 41.5 dB. In general, the detectability of a complex improved as the number of antiphasic components increased from one to three. Thresholds measured when all three components were presented but only one was antiphasic were greater than those obtained for single antiphasic tones, even when Δfs were large relative to critical bandwidths. The deleterious effect of homophasic components on detection is consistent with the notion that the binaural system integrates interaural information across ranges of frequency that are considerably wider than the critical bandwidth.