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Sample records for a-weighted sound pressure

  1. Developing a Weighted Measure of Speech Sound Accuracy

    ERIC Educational Resources Information Center

    Preston, Jonathan L.; Ramsdell, Heather L.; Oller, D. Kimbrough; Edwards, Mary Louise; Tobin, Stephen J.

    2011-01-01

    Purpose: To develop a system for numerically quantifying a speaker's phonetic accuracy through transcription-based measures. With a focus on normal and disordered speech in children, the authors describe a system for differentially weighting speech sound errors on the basis of various levels of phonetic accuracy using a Weighted Speech Sound…

  2. Developing a Weighted Measure of Speech Sound Accuracy

    ERIC Educational Resources Information Center

    Preston, Jonathan L.; Ramsdell, Heather L.; Oller, D. Kimbrough; Edwards, Mary Louise; Tobin, Stephen J.

    2011-01-01

    Purpose: To develop a system for numerically quantifying a speaker's phonetic accuracy through transcription-based measures. With a focus on normal and disordered speech in children, the authors describe a system for differentially weighting speech sound errors on the basis of various levels of phonetic accuracy using a Weighted Speech Sound…

  3. Spatial and temporal determinants of A-weighted and frequency specific sound levels-An elastic net approach.

    PubMed

    Walker, Erica D; Hart, Jaime E; Koutrakis, Petros; Cavallari, Jennifer M; VoPham, Trang; Luna, Marcos; Laden, Francine

    2017-11-01

    Urban sound levels are a ubiquitous environmental stressor and have been shown to be associated with a wide variety of health outcomes. While much is known about the predictors of A-weighted sound pressure levels in the urban environment, far less is known about other frequencies. To develop a series of spatial-temporal sound models to predict A-weighted sound pressure levels, low, mid, and high frequency sound for Boston, Massachusetts. Short-term sound levels were gathered at n = 400 sites from February 2015 - February 2016. Spatial and meteorological attributes at or near the sound monitoring site were obtained using publicly available data and a portable weather station. An elastic net variable selection technique was used to select predictors of A-weighted, low, mid, and high frequency sound. The final models for low, mid, high, and A-weighted sound levels explained 59 - 69% of the variability in each measure. Similar to other A-weighted models, our sound models included transportation related variables such as length of roads and bus lines in the surrounding area; distance to road and rail lines; traffic volume, vehicle mix, residential and commercial land use. However, frequency specific models highlighted additional predictors not included in the A-weighted model including temperature, vegetation, impervious surfaces, vehicle mix, and density of entertainment establishments and restaurants. Building spatial temporal models to characterize sound levels across the frequency spectrum using an elastic net approach can be a promising tool for noise exposure assessments within the urban soundscape. Models of sound's character may give us additional important sound exposure metrics to be utilized in epidemiological studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Sound field separation with sound pressure and particle velocity measurements.

    PubMed

    Fernandez-Grande, Efren; Jacobsen, Finn; Leclère, Quentin

    2012-12-01

    In conventional near-field acoustic holography (NAH) it is not possible to distinguish between sound from the two sides of the array, thus, it is a requirement that all the sources are confined to only one side and radiate into a free field. When this requirement cannot be fulfilled, sound field separation techniques make it possible to distinguish between outgoing and incoming waves from the two sides, and thus NAH can be applied. In this paper, a separation method based on the measurement of the particle velocity in two layers and another method based on the measurement of the pressure and the velocity in a single layer are proposed. The two methods use an equivalent source formulation with separate transfer matrices for the outgoing and incoming waves, so that the sound from the two sides of the array can be modeled independently. A weighting scheme is proposed to account for the distance between the equivalent sources and measurement surfaces and for the difference in magnitude between pressure and velocity. Experimental and numerical studies have been conducted to examine the methods. The double layer velocity method seems to be more robust to noise and flanking sound than the combined pressure-velocity method, although it requires an additional measurement surface. On the whole, the separation methods can be useful when the disturbance of the incoming field is significant. Otherwise the direct reconstruction is more accurate and straightforward.

  5. Broadband sound pressure enhancement in passive metafluids

    NASA Astrophysics Data System (ADS)

    Popa, Bogdan-Ioan

    2017-09-01

    Acoustic sensors operating in lossy environments, such as water, require significant sensitivity to overcome the sound attenuation in the environment and thus see farther. We show here that a surprisingly large class of passive fluids has the ability to enhance the sound pressure propagating inside them without employing active actuation. Specifically, the general requirements for this remarkable property are fluid impedance higher than the impedance of the environment and negligible insertion loss as sound propagates from the environment into the high impedance fluid. We demonstrate the pressure enhancing effect by designing a broadband isotropic metafluid that increases the pressure of sound waves impinging from water. We validate the design in numerical simulations showing that significant sound pressure level increases are achievable in realistic metafluid structures in large bandwidths covering several octaves. Our approach opens up unexplored avenues towards improving acoustic transducer sensitivity, which is critical in applications, such as medical ultrasound imaging, sonar, and acoustic communications.

  6. Sound pressure level generated by individual portable sound equipment.

    PubMed

    Santos, Izabella dos; Colella-Santos, Maria Francisca; Couto, Christiane Marques do

    2014-01-01

    The use of Personal Digital Audio Players can cause hearing injuries, as the sound is generated directly in the ear canal. It is believed that different types of headphones can cause different amplifications, since they cause changes in the volume and resonance of the ear canal according to their depth. This study aimed to determine the sound pressure to which young individuals are exposed when using Personal Digital Audio Players with two types of headphones: insertion earphones and anatomical insertion earphones. This was an experimental study. The probe microphone measurements were made with different headphones in 54 ears (27 young individuals). The resonance peaks were also recorded. A statistically significant difference was observed between the evaluated headphones, showing that anatomical insertion earphones had higher levels of sound pressure than insertion earphones for all frequencies measured. There was no correlation between the resonance peak of the closed canal and the frequency where the highest sound pressure level was obtained. There was a significant difference between ears at some frequencies with the different headphones. It was concluded that anatomical insertion earphones generate a higher sound pressure level than insertion earphones.

  7. Optical Measurement Of Sound Pressure

    NASA Technical Reports Server (NTRS)

    Trinh, Eugene H.; Gaspar, Mark; Leung, Emily W.

    1989-01-01

    Noninvasive technique does not disturb field it measures. Sound field deflects laser beam proportionally to its amplitude. Knife edge intercepts undeflected beam, allowing only deflected beam to reach photodetector. Apparatus calibrated by comparing output of photodetector with that of microphone. Optical technique valuable where necessary to measure in remote, inaccessible, or hostile environment or to avoid perturbation of measured region.

  8. Program Computes Sound Pressures at Rocket Launches

    NASA Technical Reports Server (NTRS)

    Ogg, Gary; Heyman, Roy; White, Michael; Edquist, Karl

    2005-01-01

    Launch Vehicle External Sound Pressure is a computer program that predicts the ignition overpressure and the acoustic pressure on the surfaces and in the vicinity of a rocket and launch pad during launch. The program generates a graphical user interface (GUI) that gathers input data from the user. These data include the critical dimensions of the rocket and of any launch-pad structures that may act as acoustic reflectors, the size and shape of the exhaust duct or flame deflector, and geometrical and operational parameters of the rocket engine. For the ignition-overpressure calculations, histories of the chamber pressure and mass flow rate also are required. Once the GUI has gathered the input data, it feeds them to ignition-overpressure and launch-acoustics routines, which are based on several approximate mathematical models of distributed sources, transmission, and reflection of acoustic waves. The output of the program includes ignition overpressures and acoustic pressures at specified locations.

  9. Automated analysis of blood pressure measurements (Korotkov sound)

    NASA Technical Reports Server (NTRS)

    Golden, D. P.; Hoffler, G. W.; Wolthuis, R. A.

    1972-01-01

    Automatic system for noninvasive measurements of arterial blood pressure is described. System uses Korotkov sound processor logic ratios to identify Korotkov sounds. Schematic diagram of system is provided to show components and method of operation.

  10. Analysis of sound pressure levels emitted by children's toys.

    PubMed

    Sleifer, Pricila; Gonçalves, Maiara Santos; Tomasi, Marinês; Gomes, Erissandra

    2013-06-01

    To verify the levels of sound pressure emitted by non-certified children's toys. Cross-sectional study of sound toys available at popular retail stores of the so-called informal sector. Electronic, mechanical, and musical toys were analyzed. The measurement of each product was carried out by an acoustic engineer in an acoustically isolated booth, by a decibel meter. To obtain the sound parameters of intensity and frequency, the toys were set to produce sounds at a distance of 10 and 50cm from the researcher's ear. The intensity of sound pressure [dB(A)] and the frequency in hertz (Hz) were measured. 48 toys were evaluated. The mean sound pressure 10cm from the ear was 102±10 dB(A), and at 50cm, 94±8 dB(A), with p<0.05. The level of sound pressure emitted by the majority of toys was above 85dB(A). The frequency ranged from 413 to 6,635Hz, with 56.3% of toys emitting frequency higher than 2,000Hz. The majority of toys assessed in this research emitted a high level of sound pressure.

  11. Differential Intracochlear Sound Pressure Measurements in Normal Human Temporal Bones

    NASA Astrophysics Data System (ADS)

    Nakajima, Hideko Heidi; Dong, Wei; Olson, Elizabeth S.; Merchant, Saumil N.; Ravicz, Michael E.; Rosowski, John J.

    2009-02-01

    We present the first simultaneous sound pressure measurements in scala vestibuli and scala tympani of the cochlea in human cadaveric temporal bones. Micro-scale fiberoptic pressure sensors enabled the study of differential sound pressure at the cochlear base. This differential pressure is the input to the cochlear partition, driving cochlear waves and auditory transduction. Results showed that: pressure of scala vestibuli was much greater than scala tympani except at low and high frequencies where scala tympani pressure affects the input to the cochlea; the differential pressure proved to be an excellent measure of normal ossicular transduction of sound (shown to decrease 30-50 dB with ossicular disarticulation, whereas the individual scala pressures were significantly affected by non-ossicular conduction of sound at high frequencies); the middle-ear gain and differential pressure were generally bandpass in frequency dependence; and the middle-ear delay in the human was over twice that of the gerbil. Concurrent stapes velocity measurements allowed determination of the differential impedance across the partition and round-window impedance. The differential impedance was generally resistive, while the round-window impedance was consistent with a compliance in conjunction with distributed inertia and damping. Our techniques can be used to study inner-ear conductive pathologies (e.g., semicircular dehiscence), as well as non-ossicular cochlear stimulation (e.g., round-window stimulation) - situations that cannot be completely quantified by measurements of stapes velocity or scala-vestibuli pressure by themselves.

  12. MRI acoustic noise: sound pressure and frequency analysis.

    PubMed

    Counter, S A; Olofsson, A; Grahn, H F; Borg, E

    1997-01-01

    The large gradient coils used in MRI generate, simultaneously with the pulsed radiofrequency (RF) wave, acoustic noise of high intensity that has raised concern regarding hearing safety. The sound pressure levels (SPLs) and power spectra of MRI acoustic noise were measured at the position of the human head in the isocenter of five MRI systems and with 10 different pulse sequences used in clinical MR scanning. Each protocol, including magnetization-prepared rapid gradient echo (MP-RAGE; 113 dB SPL linear), fast gradient echo turbo (114 dB SPL linear), and spin echo T1/2 mm (117 dB SPL linear), was found to have the high SPLs, rapid pulse rates, amplitude-modulated pulse envelopes, and multipeaked spectra. Since thickness and SPL were inversely related, the T1-weighted images generated more intense acoustic noise than the proton-dense T2-weighted measures. The unfiltered linear peak values provided more accurate measurements of the SPL and spectral content of the MRI acoustic noise than the commonly used dB A-weighted scale, which filters out the predominant low frequency components. Fourier analysis revealed predominantly low frequency energy peaks ranging from .05 to approximately 1 kHz, with a steep high frequency cutoff for each pulse sequence. Ear protectors of known attenuation ratings are recommended for all patients during MRI testing.

  13. Sounding experiments of high pressure gas discharge

    SciTech Connect

    Biele, Joachim K.

    1998-07-10

    A high pressure discharge experiment (200 MPa, 5{center_dot}10{sup 21} molecules/cm{sup 3}, 3000 K) has been set up to study electrically induced shock waves. The apparatus consists of the combustion chamber (4.2 cm{sup 3}) to produce high pressure gas by burning solid propellant grains to fill the electrical pump chamber (2.5 cm{sup 3}) containing an insulated coaxial electrode. Electrical pump energy up to 7.8 kJ at 10 kV, which is roughly three times of the gas energy in the pump chamber, was delivered by a capacitor bank. From the current-voltage relationship the discharge develops at rapidly decreasing voltage. Pressure at the combustion chamber indicating significant underpressure as well as overpressure peaks is followed by an increase of static pressure level. These data are not yet completely understood. However, Lorentz forces are believed to generate pinching with subsequent pinch heating, resulting in fast pressure variations to be propagated as rarefaction and shock waves, respectively. Utilizing pure axisymmetric electrode initiation rather than often used exploding wire technology in the pump chamber, repeatable experiments were achieved.

  14. A Comparative Study of Sound Speed in Air at Room Temperature between a Pressure Sensor and a Sound Sensor

    ERIC Educational Resources Information Center

    Amrani, D.

    2013-01-01

    This paper deals with the comparison of sound speed measurements in air using two types of sensor that are widely employed in physics and engineering education, namely a pressure sensor and a sound sensor. A computer-based laboratory with pressure and sound sensors was used to carry out measurements of air through a 60 ml syringe. The fast Fourier…

  15. A Comparative Study of Sound Speed in Air at Room Temperature between a Pressure Sensor and a Sound Sensor

    ERIC Educational Resources Information Center

    Amrani, D.

    2013-01-01

    This paper deals with the comparison of sound speed measurements in air using two types of sensor that are widely employed in physics and engineering education, namely a pressure sensor and a sound sensor. A computer-based laboratory with pressure and sound sensors was used to carry out measurements of air through a 60 ml syringe. The fast Fourier…

  16. A Sound Pressure-level Meter Without Amplification

    NASA Technical Reports Server (NTRS)

    Stowell, E Z

    1937-01-01

    The N.A.C.A. has developed a simple pressure-level meter for the measurement of sound-pressure levels above 70 db. The instrument employs a carbon microphone but has no amplification. The source of power is five flashlight batteries. Measurements may be made up to the threshold of feeling with an accuracy of plus or minus 2 db; band analysis of complex spectra may be made if desired.

  17. Wind turbine sound pressure level calculations at dwellings.

    PubMed

    Keith, Stephen E; Feder, Katya; Voicescu, Sonia A; Soukhovtsev, Victor; Denning, Allison; Tsang, Jason; Broner, Norm; Leroux, Tony; Richarz, Werner; van den Berg, Frits

    2016-03-01

    This paper provides calculations of outdoor sound pressure levels (SPLs) at dwellings for 10 wind turbine models, to support Health Canada's Community Noise and Health Study. Manufacturer supplied and measured wind turbine sound power levels were used to calculate outdoor SPL at 1238 dwellings using ISO [(1996). ISO 9613-2-Acoustics] and a Swedish noise propagation method. Both methods yielded statistically equivalent results. The A- and C-weighted results were highly correlated over the 1238 dwellings (Pearson's linear correlation coefficient r > 0.8). Calculated wind turbine SPLs were compared to ambient SPLs from other sources, estimated using guidance documents from the United States and Alberta, Canada.

  18. Prediction of light aircraft interior sound pressure level from the measured sound power flowing in to the cabin

    NASA Technical Reports Server (NTRS)

    Atwal, Mahabir S.; Heitman, Karen E.; Crocker, Malcolm J.

    1986-01-01

    The validity of the room equation of Crocker and Price (1982) for predicting the cabin interior sound pressure level was experimentally tested using a specially constructed setup for simultaneous measurements of transmitted sound intensity and interior sound pressure levels. Using measured values of the reverberation time and transmitted intensities, the equation was used to predict the space-averaged interior sound pressure level for three different fuselage conditions. The general agreement between the room equation and experimental test data is considered good enough for this equation to be used for preliminary design studies.

  19. Temperature/pressure and water vapor sounding with microwave spectroscopy

    NASA Technical Reports Server (NTRS)

    Muhleman, D. O.; Janssen, M. A.; Clancy, R. T.; Gulkis, S.; Mccleese, D. J.; Zurek, R.; Haberle, R. M.; Frerking, M.

    1992-01-01

    Two intense microwave spectra lines exist in the martian atmosphere that allow unique sounding capabilities: water vapor at 183 GHz and the (2-1) rotational line of CO at 230 GHz. Microwave spectra line sounding is a well-developed technique for the Earth's atmosphere for sounding from above from spacecraft and airplanes, and from below from fixed surface sites. Two simple instruments for temperature sounding on Mars (the CO line) and water vapor measurements are described. The surface sounder proposed for the MESUR sites is designed to study the boundary layer water vapor distribution and the temperature/pressure profiles with vertical resolution of 0.25 km up to 1 km with reduced resolution above approaching a scale height. The water channel will be sensitive to a few tenths of a micrometer of water and the temperature profile will be retrieved to an accuracy between 1 and 2 K. The latter is routinely done on the Earth using oxygen lines near 60 GHz. The measurements are done with a single-channel heterodyne receiver looking into a 10-cm mirror that is canned through a range of elevation angles plus a target load. The frequency of the receiver is sweep across the water and CO lines generating the two spectra at about 1-hr intervals throughout the mission. The mass and power for the proposed instrument are 2 kg and 5-8 W continuously. The measurements are completely immune to the atmospheric dust and ice particle loads. It was felt that these measurements are the ultimate ones to properly study the martian boundary layer from the surface to a few kilometers. Sounding from above requires an orbiting spacecraft with multichannel microwave spectrometers such as the instrument proposed for MO by a subset of the authors, a putative MESUR orbiter, and a proposed Discovery mission called MOES. Such an instrument can be built with less than 10 kg and use less than 15 W. The obvious advantage of this approach is that the entire atmosphere can be sounded for temperature and

  20. Sound-driven fluid dynamics in pressurized carbon dioxide.

    PubMed

    van Iersel, Maikel M; Mettin, Robert; Benes, Nieck E; Schwarzer, Dirk; Keurentjes, Jos T F

    2010-07-28

    Using high-speed visualization we demonstrate that ultrasound irradiation of pressurized carbon dioxide (CO(2)) induces phenomena that do not occur in ordinary liquids at ambient conditions. For a near-critical mixture of CO(2) and argon, sonication leads to extremely fast local phase separation, in which the system enters and leaves the two-phase region with the frequency of the imposed sound field. This phase transition can propagate with the speed of sound, but can also be located at fixed positions in the case of a standing sound wave. Sonication of a vapor-liquid interface creates a fine dispersion of liquid and vapor, irrespective whether the ultrasound horn is placed in the liquid or the vapor phase. In the absence of an interface, sonication of the liquid leads to ejection of a macroscopic vapor phase from the ultrasound horn with a velocity of several meters per second in the direction of wave propagation. The findings reported here potentially provide a tunable and noninvasive means for enhancing mass and heat transfer in high-pressure fluids.

  1. Estimation of absolute sound pressure in a small-sized sonochemical reactor.

    PubMed

    Sato, Shinji; Wada, Yuji; Koyama, Daisuke; Nakamura, Kentaro

    2013-01-01

    A small-sized sonochemical reactor in which the absolute value of the sound pressure amplitude can be estimated from the vibration velocity of the transducer was investigated. The sound pressure distribution in the reactor and the relationship between the vibration velocity and the sound pressure amplitude were derived through Helmholtz wave equation. The reactor consists of a bolt-clamped Langevin transducer and a rectangular cell with a tungsten reflector. A 3λ/4-standing-wave-field was generated in the reactor to simplify the sound pressure distribution. The sound pressure distribution was measured from the optical refractive index change of water using a laser interferometer. The experimental and theoretical results showed a good agreement in the absolute value of the sound pressure amplitude, and it was confirmed that the sound pressure in the sonochemical reactor can be estimated from the input current of the vibrator. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Reference equivalent threshold sound pressure levels for insert earphones.

    PubMed

    Arlinger, S; Kinnefors, C

    1989-01-01

    Insert earphones, coupled to the ear canal by means of a long plastic tube and soft ear plug (Etymotic Research ER-3A Tubephone) are being used for a number of audiometric applications as an alternative to supra-aural earphones. This report presents the results of hearing threshold level measurements in 36 ears of young, otologically normal listeners. The results are expressed as mean sound pressure levels measured on a 2 cm3 coupler according to IEC 126 as well as on an ear simulator according to IEC 711.

  3. Sound velocity determination of PbTe under pressure

    NASA Astrophysics Data System (ADS)

    Jacobsen, Matthew; Liu, Wei; Li, Baosheng

    2013-06-01

    Recent investigations of PbTe have revealed interesting high pressure transitions resulting in improved thermoelectric performance. High pressure sound velocities of PbTe have been measured to 14 GPa using an ultrasonic interferometric method. Elastic moduli and their pressure derivatives for phases in this range have been obtained using a finite strain approach. From this, an estimate of the acoustic phonon contribution to the thermal conductivity is made. By combining this with previous determinations of the thermal conductivity due to electrons, a significantly lower value than the previously determined total thermal conductivity is found. This is interpreted as evidence for coupling between the low-lying transverse optic (TO) and longitudinal acoustic (LA) modes allowing transfer of thermal energy between them. The application of pressure causes energy transference between the optical modes and electron population, which is likely the cause of the increased thermoelectric efficiency in the intermediate Pbnm state. This research is supported by the DoE/NNSA under contract number DE-FG5209NA29458 to BL. WL is also supported by the NSF under contract number EAR-1045630.

  4. Prediction of light aircraft interior sound pressure level using the room equation

    NASA Technical Reports Server (NTRS)

    Atwal, M.; Bernhard, R.

    1984-01-01

    The room equation is investigated for predicting interior sound level. The method makes use of an acoustic power balance, by equating net power flow into the cabin volume to power dissipated within the cabin using the room equation. The sound power level transmitted through the panels was calculated by multiplying the measured space averaged transmitted intensity for each panel by its surface area. The sound pressure level was obtained by summing the mean square sound pressures radiated from each panel. The data obtained supported the room equation model in predicting the cabin interior sound pressure level.

  5. Generalization of low pressure, gas-liquid, metastable sound speed to high pressures

    NASA Technical Reports Server (NTRS)

    Bursik, J. W.; Hall, R. M.

    1981-01-01

    A theory is developed for isentropic metastable sound propagation in high pressure gas-liquid mixtures. Without simplification, it also correctly predicts the minimum speed for low pressure air-water measurements where other authors are forced to postulate isothermal propagation. This is accomplished by a mixture heat capacity ratio which automatically adjusts from its single phase values to approximately the isothermal value of unity needed for the minimum speed. Computations are made for the pure components parahydrogen and nitrogen, with emphasis on the latter. With simplifying assumptions, the theory reduces to a well known approximate formula limited to low pressure.

  6. Generalization of low pressure, gas-liquid, metastable sound speed to high pressures

    NASA Technical Reports Server (NTRS)

    Bursik, J. W.; Hall, R. M.

    1981-01-01

    A theory is developed for isentropic metastable sound propagation in high pressure gas-liquid mixtures. Without simplification, it also correctly predicts the minimum speed for low pressure air-water measurements where other authors are forced to postulate isothermal propagation. This is accomplished by a mixture heat capacity ratio which automatically adjusts from its single phase values to approximately the isothermal value of unity needed for the minimum speed. Computations are made for the pure components parahydrogen and nitrogen, with emphasis on the latter. With simplifying assumptions, the theory reduces to a well known approximate formula limited to low pressure.

  7. Sound pressure level gain in an acoustic metamaterial cavity.

    PubMed

    Song, Kyungjun; Kim, Kiwon; Hur, Shin; Kwak, Jun-Hyuk; Park, Jihyun; Yoon, Jong Rak; Kim, Jedo

    2014-12-11

    The inherent attenuation of a homogeneous viscous medium limits radiation propagation, thereby restricting the use of many high-frequency acoustic devices to only short-range applications. Here, we design and experimentally demonstrate an acoustic metamaterial localization cavity which is used for sound pressure level (SPL) gain using double coiled up space like structures thereby increasing the range of detection. This unique behavior occurs within a subwavelength cavity that is 1/10(th) of the wavelength of the incident acoustic wave, which provides up to a 13 dB SPL gain. We show that the amplification results from the Fabry-Perot resonance of the cavity, which has a simultaneously high effective refractive index and effective impedance. We also experimentally verify the SPL amplification in an underwater environment at higher frequencies using a sample with an identical unit cell size. The versatile scalability of the design shows promising applications in many areas, especially in acoustic imaging and underwater communication.

  8. Sound Pressure Level Gain in an Acoustic Metamaterial Cavity

    NASA Astrophysics Data System (ADS)

    Song, Kyungjun; Kim, Kiwon; Hur, Shin; Kwak, Jun-Hyuk; Park, Jihyun; Yoon, Jong Rak; Kim, Jedo

    2014-12-01

    The inherent attenuation of a homogeneous viscous medium limits radiation propagation, thereby restricting the use of many high-frequency acoustic devices to only short-range applications. Here, we design and experimentally demonstrate an acoustic metamaterial localization cavity which is used for sound pressure level (SPL) gain using double coiled up space like structures thereby increasing the range of detection. This unique behavior occurs within a subwavelength cavity that is 1/10th of the wavelength of the incident acoustic wave, which provides up to a 13 dB SPL gain. We show that the amplification results from the Fabry-Perot resonance of the cavity, which has a simultaneously high effective refractive index and effective impedance. We also experimentally verify the SPL amplification in an underwater environment at higher frequencies using a sample with an identical unit cell size. The versatile scalability of the design shows promising applications in many areas, especially in acoustic imaging and underwater communication.

  9. Sound absorbing property of porous metal materials with high temperature and high sound pressure by turbulence analogy

    NASA Astrophysics Data System (ADS)

    Hui Wu, Jiu; Hu, Zhi Ping; Zhou, Han

    2013-05-01

    A quantitative theoretical model is presented to investigate the sound absorbing property of porous metal materials with high temperature and high sound pressure based on Kolmogorov turbulence theory in this paper. The porous materials have a large number of anomalous pores with similar scale, and these irregular pores could be considered as quasi-periodic structure that is very similar to the small-scale turbulence. Therefore, Kolmogorov turbulence theory is adopted to analyze the wave propagation inside the porous metal materials, in which the characteristic velocity and characteristic scale can be obtained by the nondimensional analysis method. Furthermore, the acoustical pressure amplitude in the porous metal materials under high temperature and high sound pressure level can be figured out with respect to metal wire diameter, porosity, and other parameters. It is shown quantitatively that the acoustic pressure amplitude goes up with an increase in the temperature and/or the sound pressure level. This model is verified by the well agreement between the theoretical and experimental results. It could provide a reliable theoretical guidance for the applications of porous metal materials in the area of vibration and noise control under high temperature and high sound pressure level.

  10. Sound velocity and density of liquid Fe-Ni-S at high pressure

    NASA Astrophysics Data System (ADS)

    Terasaki, H. G.; Kurokawa, F.; Shimoyama, Y.; Urakawa, S.; Takubo, Y.; Machida, A.; Nishida, K.; Shibazaki, Y.; Higo, Y.; Kondo, T.

    2016-12-01

    Elastic properties, such as sound velocity and density, of liquid Fe-alloys at high pressure are important for identifying light elements in the cores of terrestrial planets by comparing with geophysical observations. In this study, we have measured sound velocity and density of liquid Fe-Ni-S simultaneously using multianvil apparatus and studied the effects of pressure and sulfur content on these properties. Sound velocity and density were measured using ultrasonic pulse-echo method and X-ray absorption method, respectively. Addition of sulfur significantly reduced the sound velocity and density. Measured sound velocity of liquid Fe-Ni-S is consistent with the reported sound velocity at 15 GPa obtained from ab initio calculation (Umemoto et al. 2014). Bulk modulus and its pressure derivatives of liquid Fe-Ni-S were precisely determined from the present sound velocity and density data. Based on these results, implication of Fe-Ni-S core of the terrestrial planets will be discussed.

  11. Effects of sound-field frequency modulation amplification on reducing teachers' sound pressure level in the classroom.

    PubMed

    Sapienza, C M; Crandell, C C; Curtis, B

    1999-09-01

    Voice problems are a frequent difficulty that teachers experience. Common complaints by teachers include vocal fatigue and hoarseness. One possible explanation for these symptoms is prolonged elevations in vocal loudness within the classroom. This investigation examined the effectiveness of sound-field frequency modulation (FM) amplification on reducing the sound pressure level (SPL) of the teacher's voice during classroom instruction. Specifically, SPL was examined during speech produced in a classroom lecture by 10 teachers with and without the use of sound-field amplification. Results indicated a significant 2.42-dB decrease in SPL with the use of sound-field FM amplification. These data support the use of sound-field amplification in the vocal hygiene regimen recommended to teachers by speech-language pathologists.

  12. Stream ambient noise, spectrum and propagation of sounds in the goby Padogobius martensii: sound pressure and particle velocity.

    PubMed

    Lugli, Marco; Fine, Michael L

    2007-11-01

    The most sensitive hearing and peak frequencies of courtship calls of the stream goby, Padogobius martensii, fall within a quiet window at around 100 Hz in the ambient noise spectrum. Acoustic pressure was previously measured although Padogobius likely responds to particle motion. In this study a combination pressure (p) and particle velocity (u) detector was utilized to describe ambient noise of the habitat, the characteristics of the goby's sounds and their attenuation with distance. The ambient noise (AN) spectrum is generally similar for p and u (including the quiet window at noisy locations), although the energy distribution of u spectrum is shifted up by 50-100 Hz. The energy distribution of the goby's sounds is similar for p and u spectra of the Tonal sound, whereas the pulse-train sound exhibits larger p-u differences. Transmission loss was high for sound p and u: energy decays 6-10 dB10 cm, and sound pu ratio does not change with distance from the source in the nearfield. The measurement of particle velocity of stream AN and P. martensii sounds indicates that this species is well adapted to communicate acoustically in a complex noisy shallow-water environment.

  13. 16 CFR 1500.47 - Method for determining the sound pressure level produced by toy caps.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Method for determining the sound pressure level produced by toy caps. 1500.47 Section 1500.47 Commercial Practices CONSUMER PRODUCT SAFETY... ENFORCEMENT REGULATIONS § 1500.47 Method for determining the sound pressure level produced by toy caps. (a...

  14. 16 CFR 1500.47 - Method for determining the sound pressure level produced by toy caps.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Method for determining the sound pressure level produced by toy caps. 1500.47 Section 1500.47 Commercial Practices CONSUMER PRODUCT SAFETY... ENFORCEMENT REGULATIONS § 1500.47 Method for determining the sound pressure level produced by toy caps. (a...

  15. 16 CFR 1500.47 - Method for determining the sound pressure level produced by toy caps.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Method for determining the sound pressure level produced by toy caps. 1500.47 Section 1500.47 Commercial Practices CONSUMER PRODUCT SAFETY... ENFORCEMENT REGULATIONS § 1500.47 Method for determining the sound pressure level produced by toy caps. (a...

  16. Global sound modes in mirror traps with anisotropic pressure

    SciTech Connect

    Skovorodin, D. I.; Zaytsev, K. V.; Beklemishev, A. D.

    2013-10-15

    Global oscillations of inhomogeneous plasma with frequencies close to the bounce frequency of ions in mirror traps have been studied. It has been shown that, in some cases, the sound can be reflected from the axial plasma inhomogeneity. The ideal magnetohydrodynamic (MHD) model with Chew-Goldberger-Low approximation has been utilized to determine conditions of existence of the standing waves in the mirror-confined plasma. Linearized wave equation for the longitudinal plasma oscillations in thin anisotropic inhomogeneous plasma with finite β has been derived. The wave equation has been treated numerically. The oscillations are studied for the case of the trap with partially filled loss-cone and the trap with sloshing ions. It has been shown that in cells of the multiple-mirror trap standing waves can exist. The frequency of the wave is of the order of the mean bounce-frequency of ions. In the trap with sloshing ions, the mode supported by the pressure of fast ions could exist. The results of oscillations observation in the experiment on the Gas Dynamic Trap have been presented.

  17. Sound pressure distribution within natural and artificial human ear canals: Forward stimulation

    PubMed Central

    Ravicz, Michael E.; Tao Cheng, Jeffrey; Rosowski, John J.

    2014-01-01

    This work is part of a study of the interaction of sound pressure in the ear canal (EC) with tympanic membrane (TM) surface displacement. Sound pressures were measured with 0.5–2 mm spacing at three locations within the shortened natural EC or an artificial EC in human temporal bones: near the TM surface, within the tympanic ring plane, and in a plane transverse to the long axis of the EC. Sound pressure was also measured at 2-mm intervals along the long EC axis. The sound field is described well by the size and direction of planar sound pressure gradients, the location and orientation of standing-wave nodal lines, and the location of longitudinal standing waves along the EC axis. Standing-wave nodal lines perpendicular to the long EC axis are present on the TM surface >11–16 kHz in the natural or artificial EC. The range of sound pressures was larger in the tympanic ring plane than at the TM surface or in the transverse EC plane. Longitudinal standing-wave patterns were stretched. The tympanic-ring sound field is a useful approximation of the TM sound field, and the artificial EC approximates the natural EC. PMID:25480061

  18. Sound pressure distribution within natural and artificial human ear canals: forward stimulation.

    PubMed

    Ravicz, Michael E; Tao Cheng, Jeffrey; Rosowski, John J

    2014-12-01

    This work is part of a study of the interaction of sound pressure in the ear canal (EC) with tympanic membrane (TM) surface displacement. Sound pressures were measured with 0.5-2 mm spacing at three locations within the shortened natural EC or an artificial EC in human temporal bones: near the TM surface, within the tympanic ring plane, and in a plane transverse to the long axis of the EC. Sound pressure was also measured at 2-mm intervals along the long EC axis. The sound field is described well by the size and direction of planar sound pressure gradients, the location and orientation of standing-wave nodal lines, and the location of longitudinal standing waves along the EC axis. Standing-wave nodal lines perpendicular to the long EC axis are present on the TM surface >11-16 kHz in the natural or artificial EC. The range of sound pressures was larger in the tympanic ring plane than at the TM surface or in the transverse EC plane. Longitudinal standing-wave patterns were stretched. The tympanic-ring sound field is a useful approximation of the TM sound field, and the artificial EC approximates the natural EC.

  19. Effect of ultrasonic cavitation on measurement of sound pressure using hydrophone

    NASA Astrophysics Data System (ADS)

    Thanh Nguyen, Tam; Asakura, Yoshiyuki; Okada, Nagaya; Koda, Shinobu; Yasuda, Keiji

    2017-07-01

    Effect of ultrasonic cavitation on sound pressure at the fundamental, second harmonic, and first ultraharmonic frequencies was investigated from low to high ultrasonic intensities. The driving frequencies were 22, 304, and 488 kHz. Sound pressure was measured using a needle-type hydrophone and ultrasonic cavitation was estimated from the broadband integrated pressure (BIP). With increasing square root of electric power applied to a transducer, the sound pressure at the fundamental frequency linearly increased initially, dropped at approximately the electric power of cavitation inception, and afterward increased again. The sound pressure at the second harmonic frequency was detected just below the electric power of cavitation inception. The first ultraharmonic component appeared at around the electric power of cavitation inception at 304 and 488 kHz. However, at 22 kHz, the first ultraharmonic component appeared at a higher electric power than that of cavitation inception.

  20. Proving diamonds under ultra-high pressure with sound velocity measurements

    NASA Astrophysics Data System (ADS)

    Shigemori, Keisuke; Shimizu, Katsuya; Asakura, Yasuhiro; Sakaiya, Tatsuhiro; Kondo, Tadashi; Hironaka, Yoichiro; Irifune, Tetsuo; Sumiya, Hitoshi; Kadono, Toshihiko; Azechi, Hiroshi

    2014-10-01

    Diamond under terapascal (TPa) regime is of great interest on its phase transition to a post diamond phase. Many experimental works have been done on the diamond at the TPa regime by measuring the shock parameters (shock velocity, particle velocity). We measured sound velocities of shock-compressed diamond under several pressures by means of x-ray backlighting technique. Experiments were done on GEKKO-HIPER laser irradiation facility at Institute of Laser Engineering, Osaka University. We obtained sound velocities at a pressure of 0.4 - 2.0 TPa by changing the laser intensity. The experimental sound velocity suggests that a clear discontinuity at around 0.7 TPa where the melting of the diamond starts. The sound velocity drops then slightly increases with increasing pressure. The slope of the sound velocity over 1 TPa is lower than that under 0.7 TPa, indicating the melting of the diamond.

  1. Differential Intracochlear Sound Pressure Measurements in Human Temporal Bones with an Off-the-Shelf Sensor

    PubMed Central

    Salcher, Rolf; Püschel, Klaus; Lenarz, Thomas; Maier, Hannes

    2016-01-01

    The standard method to determine the output level of acoustic and mechanical stimulation to the inner ear is measurement of vibration response of the stapes in human cadaveric temporal bones (TBs) by laser Doppler vibrometry. However, this method is reliable only if the intact ossicular chain is stimulated. For other stimulation modes an alternative method is needed. The differential intracochlear sound pressure between scala vestibuli (SV) and scala tympani (ST) is assumed to correlate with excitation. Using a custom-made pressure sensor it has been successfully measured and used to determine the output level of acoustic and mechanical stimulation. To make this method generally accessible, an off-the-shelf pressure sensor (Samba Preclin 420 LP, Samba Sensors) was tested here for intracochlear sound pressure measurements. During acoustic stimulation, intracochlear sound pressures were simultaneously measurable in SV and ST between 0.1 and 8 kHz with sufficient signal-to-noise ratios with this sensor. The pressure differences were comparable to results obtained with custom-made sensors. Our results demonstrated that the pressure sensor Samba Preclin 420 LP is usable for measurements of intracochlear sound pressures in SV and ST and for the determination of differential intracochlear sound pressures. PMID:27610377

  2. Sound scattering by rigid oblate spheroids, with implication to pressure gradient microphones

    NASA Technical Reports Server (NTRS)

    Maciulaitis, A.; Seiner, J.; Norum, T. D.

    1976-01-01

    The frequency limit below which sound scattering by a microphone body is sufficiently small to permit accurate pressure gradient measurements was determined. The sound pressure was measured at various points on the surface of a rigid oblate spheroid illuminated by spherical waves generated by a point source at a large distance from the spheroid, insuring an essentially plane sound field. The measurements were made with small pressure microphones flush mounted from the inside of the spheroid model. Numerical solutions were obtained for a variety of spheroid shapes, including that of the experimental model. Very good agreement was achieved between the experimental and theoretical results. It was found that scattering effects are insignificant if the ratio of the major circumference of the spheroid to the wavelength of the incident sound is less than about 0.7, this number being dependent upon the shape of the spheroid. This finding can be utilized in the design of pressure gradient microphones.

  3. Effect of Ultrasound Frequency on Sonochemical Luminescence under Well-Determined Sound Pressure

    NASA Astrophysics Data System (ADS)

    Yanagida, Hirotaka; Masubuchi, Yuichi; Minagawa, Keiji; Takimoto, Jun-ichi; Koyama, Kiyohito

    1999-05-01

    By determining sound pressure using the Ramann-Nath parameterand confirming sound form based on schlieren images, weinvestigated the effects of ultrasound frequency on the sonochemicalluminescence of a luminol solution. Separating the effect into theluminescence threshold of sound energy and the rate of luminescenceincrease with respect to the sound energy, we found that the lowerthe frequency is the lower the threshold and the higher the rate ofincrease, and that only the standing-wave induces luminescence underthe conditions where the running-wave does not induce luminescenceat all.

  4. Middle ear pathology can affect the ear-canal sound pressure generated by audiologic earphones.

    PubMed

    Voss, S E; Rosowski, J J; Merchant, S N; Thornton, A R; Shera, C A; Peake, W T

    2000-08-01

    To determine how the ear-canal sound pressures generated by earphones differ between normal and pathologic middle ears. Measurements of ear-canal sound pressures generated by the Etymtic Research ER-3A insert earphone in normal ears (N = 12) were compared with the pressures generated in abnormal ears with mastoidectomy bowls (N = 15), tympanostomy tubes (N = 5), and tympanic-membrane perforations (N = 5). Similar measurements were made with the Telephonics TDH-49 supra-aural earphone in normal ears (N = 10) and abnormal ears with mastoidectomy bowls (N = 10), tympanostomy tubes (N = 4), and tympanic-membrane perforations (N = 5). With the insert earphone, the sound pressures generated in the mastoid-bowl ears were all smaller than the pressures generated in normal ears; from 250 to 1000 Hz the difference in pressure level was nearly frequency independent and ranged from -3 to -15 dB; from 1000 to 4000 Hz the reduction in level increased with frequency and ranged from -5 dB to -35 dB. In the ears with tympanostomy tubes and perforations the sound pressures were always smaller than in normal ears at frequencies below 1000 Hz; the largest differences occurred below 500 Hz and ranged from -5 to -25 dB. With the supra-aural earphone, the sound pressures in ears with the three pathologic conditions were more variable than those with the insert earphone. Generally, sound pressures in the ears with mastoid bowls were lower than those in normal ears for frequencies below about 500 Hz; above about 500 Hz the pressures showed sharp minima and maxima that were not seen in the normal ears. The ears with tympanostomy tubes and tympanic-membrane perforations also showed reduced ear-canal pressures at the lower frequencies, but at higher frequencies these ear-canal pressures were generally similar to the pressures measured in the normal ears. When the middle ear is not normal, ear-canal sound pressures can differ by up to 35 dB from the normal-ear value. Because the pressure level

  5. Visualization and Measurements of Sound Pressure Distribution of Ultrasonic Wave by Stroboscopic Real-Time Holographic Interferometry

    NASA Astrophysics Data System (ADS)

    Hisada, Shigeyoshi; Suzuki, Takahiro; Nakahara, Sumio; Fujita, Takeyoshi

    2002-05-01

    The sound pressure distribution of underwater ultrasonic waves is measured by real-time stroboscope holographic interferometry using bismuth silicon oxide single crystal. Stroboscopic sub-microsecond irradiation of laser light enables the recording of the stationary holographic interferogram of refractive index changes of water by ultrasonic waves for the frame time of a charge coupled device camera. The fringe order distribution is calculated from the interferogram by Fourier transform fringe analysis. The optical path differences caused by sound field along the optical path are converted into local field values of sound pressure, which is displayed as a gray scale distribution image. In the experiment, the sound pressure distributions of ultrasonic waves through rectangular and circular apertures are observed. They are compared with the theoretical sound pressure distribution. The sound pressure values obtained by a hydrophone show good agreement with the measured values obtained by this method. The converging and diverging sound pressure fields realized by an acoustic lens are measured.

  6. A national project to evaluate and reduce high sound pressure levels from music.

    PubMed

    Ryberg, Johanna Bengtsson

    2009-01-01

    The highest recommended sound pressure levels for leisure sounds (music) in Sweden are 100 dB LAeq and 115 dB LAFmax for adults, and 97 dB LAeq and 110 dB LAFmax where children under the age of 13 have access. For arrangements intended for children, levels should be consistently less than 90 dB LAeq. In 2005, a national project was carried out with the aim of improving environments with high sound pressure levels from music, such as concert halls, restaurants, and cinemas. The project covered both live and recorded music. Of Sweden's 290 municipalities, 134 took part in the project, and 93 of these carried out sound measurements. Four hundred and seventy one establishments were investigated, 24% of which exceeded the highest recommended sound pressure levels for leisure sounds in Sweden. Of festival and concert events, 42% exceeded the recommended levels. Those who visit music events/establishments thus run a relatively high risk of exposure to harmful sound levels. Continued supervision in this field is therefore crucial.

  7. Inner-ear sound pressures near the base of the cochlea in chinchilla: Further investigation

    PubMed Central

    Ravicz, Michael E.; Rosowski, John J.

    2013-01-01

    The middle-ear pressure gain GMEP, the ratio of sound pressure in the cochlear vestibule PV to sound pressure at the tympanic membrane PTM, is a descriptor of middle-ear sound transfer and the cochlear input for a given stimulus in the ear canal. GMEP and the cochlear partition differential pressure near the cochlear base ΔPCP, which determines the stimulus for cochlear partition motion and has been linked to hearing ability, were computed from simultaneous measurements of PV, PTM, and the sound pressure in scala tympani near the round window PST in chinchilla. GMEP magnitude was approximately 30 dB between 0.1 and 10 kHz and decreased sharply above 20 kHz, which is not consistent with an ideal transformer or a lossless transmission line. The GMEP phase was consistent with a roughly 50-μs delay between PV and PTM. GMEP was little affected by the inner-ear modifications necessary to measure PST. GMEP is a good predictor of ΔPCP at low and moderate frequencies where PV ⪢ PST but overestimates ΔPCP above a few kilohertz where PV ≈ PST. The ratio of PST to PV provides insight into the distribution of sound pressure within the cochlear scalae. PMID:23556590

  8. Inner-ear sound pressures near the base of the cochlea in chinchilla: further investigation.

    PubMed

    Ravicz, Michael E; Rosowski, John J

    2013-04-01

    The middle-ear pressure gain GMEP, the ratio of sound pressure in the cochlear vestibule PV to sound pressure at the tympanic membrane PTM, is a descriptor of middle-ear sound transfer and the cochlear input for a given stimulus in the ear canal. GMEP and the cochlear partition differential pressure near the cochlear base ΔPCP, which determines the stimulus for cochlear partition motion and has been linked to hearing ability, were computed from simultaneous measurements of PV, PTM, and the sound pressure in scala tympani near the round window PST in chinchilla. GMEP magnitude was approximately 30 dB between 0.1 and 10 kHz and decreased sharply above 20 kHz, which is not consistent with an ideal transformer or a lossless transmission line. The GMEP phase was consistent with a roughly 50-μs delay between PV and PTM. GMEP was little affected by the inner-ear modifications necessary to measure PST. GMEP is a good predictor of ΔPCP at low and moderate frequencies where PV > PST but overestimates ΔPCP above a few kilohertz where PV ≈ PST. The ratio of PST to PV provides insight into the distribution of sound pressure within the cochlear scalae.

  9. Mean Tracheal Sound Energy During Sleep is Related to Daytime Blood Pressure

    PubMed Central

    Nakano, Hiroshi; Hirayama, Kenji; Sadamitsu, Yumiko; Shin, Shizue; Iwanaga, Tomoaki

    2013-01-01

    Study Objectives: The pathological role of snoring independent of obstructive sleep apnea remains under debate. The authors hypothesized that snoring sound intensity, as assessed by mean tracheal sound energy (Leq) during sleep, is related to daytime blood pressure. Design: Retrospective analysis of clinical records and polysomnography data. Setting: Sleep laboratory at a national hospital in Japan. Patients: Consecutive patients who underwent diagnostic polysomnography with suspicion of sleep apnea between January 2005 and December 2009 (n = 1,118). Interventions: Not applicable. Measurements and Results: Leq was calculated from tracheal sound spectra recorded every 0.2 sec during polysomnography. Daytime high blood pressure (HBP) was defined as taking antihypertensive drugs or having a systolic blood pressure ≥ 140 mm Hg or a diastolic blood pressure ≥ 90 mmHg at the patient's first clinical visit. Patient age, sex, body mass index, apnea-hypopnea index, alcohol consumption, and smoking were considered as confounders. Leq during sleep was associated with HBP after adjusting for all confounding factors (n = 1,074, P = 0.00019). This association was demonstrated even in nonapneic nonobese patients (n = 232, P = 0.012). Conclusions: The association between snoring intensity, as assessed by mean sound energy, and blood pressure suggests a pathological role for heavy snoring. Further study in a general population is warranted. Citation: Nakano H; Hirayama K; Sadamitsu Y; Shin S; Iwanaga T. Mean tracheal sound energy during sleep is related to daytime blood pressure. SLEEP 2013;36(9):1361-1367. PMID:23997370

  10. Apparatus and method for processing Korotkov sounds. [for blood pressure measurement

    NASA Technical Reports Server (NTRS)

    Golden, D. P., Jr.; Hoffler, G. W.; Wolthuis, R. A. (Inventor)

    1974-01-01

    A Korotkov sound processor, used in a noninvasive automatic blood measuring system where the brachial artery is occluded by an inflatable cuff, is disclosed. The Korotkoff sound associated with the systolic event is determined when the ratio of the absolute value of a voltage signal, representing Korotkov sounds in the range of 18 to 26 Hz to a maximum absolute peak value of the unfiltered signals, first equals or exceeds a value of 0.45. Korotkov sound associated with the diastolic event is determined when a ratio of the voltage signal of the Korotkov sounds in the range of 40 to 60 Hz to the absolute peak value of such signals within a single measurement cycle first falls below a value of 0.17. The processor signals the occurrence of the systolic and diastolic events and these signals can be used to control a recorder to record pressure values for these events.

  11. MP3 player listening sound pressure levels among 10 to 17 year old students.

    PubMed

    Keith, Stephen E; Michaud, David S; Feder, Katya; Haider, Ifaz; Marro, Leonora; Thompson, Emma; Marcoux, Andre M

    2011-11-01

    Using a manikin, equivalent free-field sound pressure level measurements were made from the portable digital audio players of 219 subjects, aged 10 to 17 years (93 males) at their typical and "worst-case" volume levels. Measurements were made in different classrooms with background sound pressure levels between 40 and 52 dBA. After correction for the transfer function of the ear, the median equivalent free field sound pressure levels and interquartile ranges (IQR) at typical and worst-case volume settings were 68 dBA (IQR = 15) and 76 dBA (IQR = 19), respectively. Self-reported mean daily use ranged from 0.014 to 12 h. When typical sound pressure levels were considered in combination with the average daily duration of use, the median noise exposure level, Lex, was 56 dBA (IQR = 18) and 3.2% of subjects were estimated to exceed the most protective occupational noise exposure level limit in Canada, i.e., 85 dBA Lex. Under worst-case listening conditions, 77.6% of the sample was estimated to listen to their device at combinations of sound pressure levels and average daily durations for which there is no known risk of permanent noise-induced hearing loss, i.e., ≤  75 dBA Lex. Sources and magnitudes of measurement uncertainties are also discussed.

  12. Investigation of the level difference between sound pressure and sound intensity in an aircraft cabin under different fuselage conditions

    NASA Technical Reports Server (NTRS)

    Atwal, M. S.; Crocker, M. J.; Heitman, K. E.

    1985-01-01

    Problems in using two-microphone sound-intensity (SI) measurements to measure structural transmission losses are investigated in experiments involving light-aircraft fuselage panels and windows. Both sound pressure (SP) and SI are measured near the passenger and door windows and panels of a single-engine aircraft and with these barriers removed, and the effect of increasing interior acoustic absorption and blocking flanking transmission paths is also tested. The results are presented graphically, and the SP measurements are used to indicate frequency ranges in which the two-microphone technique significantly underestimates SI. It is inferred that flanking paths and interior reverberation must be effectively suppressed in order to obtain accurate transmission-loss measurements.

  13. Numerical and analytical solutions for sound propagation and absorption in porous media at high sound pressure levels.

    PubMed

    Zhang, Bo; Chen, Tianning; Zhao, Yuyuan; Zhang, Weiyong; Zhu, Jian

    2012-09-01

    On the basis of the work of Wilson et al. [J. Acoust. Soc. Am. 84, 350-359 (1988)], a more exact numerical approach was constructed for predicting the nonlinear sound propagation and absorption properties of rigid porous media at high sound pressure levels. The numerical solution was validated by the experimental results for sintered fibrous porous steel samples and its predictions were compared with the numerical solution of Wilson et al. An approximate analytical solution was further put forward for the normalized surface acoustic admittance of rigid air-saturated porous materials with infinite thickness, based on the wave perturbation method developed by Lambert and McIntosh [J. Acoust. Soc. Am. 88, 1950-1959 (1990)]. Comparisons were made with the numerical results.

  14. Investigation of the level difference between sound pressure and sound intensity in an aircraft cabin under different fuselage conditions

    NASA Technical Reports Server (NTRS)

    Atwal, M. S.; Crocker, M. J.; Heitman, K. E.

    1985-01-01

    Problems in using two-microphone sound-intensity (SI) measurements to measure structural transmission losses are investigated in experiments involving light-aircraft fuselage panels and windows. Both sound pressure (SP) and SI are measured near the passenger and door windows and panels of a single-engine aircraft and with these barriers removed, and the effect of increasing interior acoustic absorption and blocking flanking transmission paths is also tested. The results are presented graphically, and the SP measurements are used to indicate frequency ranges in which the two-microphone technique significantly underestimates SI. It is inferred that flanking paths and interior reverberation must be effectively suppressed in order to obtain accurate transmission-loss measurements.

  15. Pressure dependence of quantum zero sound attenuation in normal liquid3He

    NASA Astrophysics Data System (ADS)

    Matsumoto, Koichi; Ikegami, Toru; Karaki, Koichi; Okuda, Yuichi

    1996-01-01

    In the Fermi liquid theory Landau predicted that sound quanta are absorbed and emitted by directly creating and annihilating quasiparticle-quasihole pairs in normal liquid3He, when the angular frequency of ultrasound satisfies the condition Ћω> kT. In this regime sound attenuation remains finite at absolute zero temperature. We studied this quantum absorption limit as a function of pressure using an ultrasound of 389.1 MHz and have verified that this quantum zero sound absorption does exist.

  16. Simulating cartilage conduction sound to estimate the sound pressure level in the external auditory canal

    NASA Astrophysics Data System (ADS)

    Shimokura, Ryota; Hosoi, Hiroshi; Nishimura, Tadashi; Iwakura, Takashi; Yamanaka, Toshiaki

    2015-01-01

    When the aural cartilage is made to vibrate it generates sound directly into the external auditory canal which can be clearly heard. Although the concept of cartilage conduction can be applied to various speech communication and music industrial devices (e.g. smartphones, music players and hearing aids), the conductive performance of such devices has not yet been defined because the calibration methods are different from those currently used for air and bone conduction. Thus, the aim of this study was to simulate the cartilage conduction sound (CCS) using a head and torso simulator (HATS) and a model of aural cartilage (polyurethane resin pipe) and compare the results with experimental ones. Using the HATS, we found the simulated CCS at frequencies above 2 kHz corresponded to the average measured CCS from seven subjects. Using a model of skull bone and aural cartilage, we found that the simulated CCS at frequencies lower than 1.5 kHz agreed with the measured CCS. Therefore, a combination of these two methods can be used to estimate the CCS with high accuracy.

  17. Separation and reconstruction of high pressure water-jet reflective sound signal based on ICA

    NASA Astrophysics Data System (ADS)

    Yang, Hongtao; Sun, Yuling; Li, Meng; Zhang, Dongsu; Wu, Tianfeng

    2011-12-01

    The impact of high pressure water-jet on the different materials target will produce different reflective mixed sound. In order to reconstruct the reflective sound signals distribution on the linear detecting line accurately and to separate the environment noise effectively, the mixed sound signals acquired by linear mike array were processed by ICA. The basic principle of ICA and algorithm of FASTICA were described in detail. The emulation experiment was designed. The environment noise signal was simulated by using band-limited white noise and the reflective sound signal was simulated by using pulse signal. The reflective sound signal attenuation produced by the different distance transmission was simulated by weighting the sound signal with different contingencies. The mixed sound signals acquired by linear mike array were synthesized by using the above simulated signals and were whitened and separated by ICA. The final results verified that the environment noise separation and the reconstruction of the detecting-line sound distribution can be realized effectively.

  18. Relationship Between Subglottal Pressure and Sound Pressure Level in Untrained Voices.

    PubMed

    Björklund, Staffan; Sundberg, Johan

    2016-01-01

    Subglottal pressure (P(s)) is strongly correlated with sound pressure level (SPL) and is easy to measure by means of commonly available equipment. The SPL/Ps ratio is strongly dependent on the efficiency of the phonatory apparatus and should be of great relevance to clinical practice. However, published normative data are still missing. The subjects produced sequences of the syllable [pæ], and P(s) was measured as the oral pressure during the [p] occlusion. The P(s) to SPL relationship was determined at four pitches produced by 16 female and 15 male healthy voices and analyzed by means of regression analysis. Average correlation between P(s) and SPL, average SPL produced with a P(s) of 10 cm H(2)O, and average SPL increase produced by a doubling of P(s) were calculated for the female and for the male subjects. The significance of sex and pitch conditions was analyzed by means of analysis of variance (ANOVA). Pitch was found to be an insignificant condition. The average correlation between P(s) and SPL was 0.83 and did not differ significantly between the female and male subjects. In female and male subjects, P(s) = 10 cm H(2)O produced 78.1 dB and 80.0 dB SPL at 0.3 m, and a doubling of P(s) generated 11.1 dB and 9.3 dB increase of SPL. Both these gender differences were statistically significant. The relationship between Ps and SPL can be reliably established from series of repetitions of the syllable [pæ] produced with a continuously changing degree of vocal loudness. Male subjects produce slightly higher SPL for a given pressure than female subjects but gain less for a doubling of P(s). As these relationships appear to be affected by phonation type, it seems possible that in the future, the method can be used for documenting degree of phonatory hypofunction and hyperfunction. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  19. An analysis of collegiate band directors' exposure to sound pressure levels

    NASA Astrophysics Data System (ADS)

    Roebuck, Nikole Moore

    Noise-induced hearing loss (NIHL) is a significant but unfortunate common occupational hazard. The purpose of the current study was to measure the magnitude of sound pressure levels generated within a collegiate band room and determine if those sound pressure levels are of a magnitude that exceeds the policy standards and recommendations of the Occupational Safety and Health Administration (OSHA), and the National Institute of Occupational Safety and Health (NIOSH). In addition, reverberation times were measured and analyzed in order to determine the appropriateness of acoustical conditions for the band rehearsal environment. Sound pressure measurements were taken from the rehearsal of seven collegiate marching bands. Single sample t test were conducted to compare the sound pressure levels of all bands to the noise exposure standards of OSHA and NIOSH. Multiple regression analysis were conducted and analyzed in order to determine the effect of the band room's conditions on the sound pressure levels and reverberation times. Time weighted averages (TWA), noise percentage doses, and peak levels were also collected. The mean Leq for all band directors was 90.5 dBA. The total accumulated noise percentage dose for all band directors was 77.6% of the maximum allowable daily noise dose under the OSHA standard. The total calculated TWA for all band directors was 88.2% of the maximum allowable daily noise dose under the OSHA standard. The total accumulated noise percentage dose for all band directors was 152.1% of the maximum allowable daily noise dose under the NIOSH standards, and the total calculated TWA for all band directors was 93dBA of the maximum allowable daily noise dose under the NIOSH standard. Multiple regression analysis revealed that the room volume, the level of acoustical treatment and the mean room reverberation time predicted 80% of the variance in sound pressure levels in this study.

  20. Liquid sound speeds at pressure from the optical analyzer technique

    SciTech Connect

    Fritz, J.N.; Morris, C.E.; Hixson, R.S.; McQueen, R.G.

    1993-08-01

    The optical analyzer technique has proved to be a useful means of obtaining wave velocities at high pressures. Stepped wedges of the investigated material emit shock, and later, rarefaction waves into a transparent analyzer covering the material. The time interval between shock and rarefaction plotted versus wedge thickness gives a linear plot whose intercept fixes the target/driver thickness ratio for exact wave overtake, and thus gives a relation between the shock velocity and overtaking wave velocity at pressure. The slope of this line is intimately related to the wave velocity at pressure of the analyzer in front of the wedge. This aspect of the technique has not yet been exploited. We present the appropriate analysis, some data on bromoform (one of the analyzers used), and discuss some possible applications of this technique.

  1. Experimental and numerical characterization of the sound pressure in standing wave acoustic levitators

    NASA Astrophysics Data System (ADS)

    Stindt, A.; Andrade, M. A. B.; Albrecht, M.; Adamowski, J. C.; Panne, U.; Riedel, J.

    2014-01-01

    A novel method for predictions of the sound pressure distribution in acoustic levitators is based on a matrix representation of the Rayleigh integral. This method allows for a fast calculation of the acoustic field within the resonator. To make sure that the underlying assumptions and simplifications are justified, this approach was tested by a direct comparison to experimental data. The experimental sound pressure distributions were recorded by high spatially resolved frequency selective microphone scanning. To emphasize the general applicability of the two approaches, the comparative studies were conducted for four different resonator geometries. In all cases, the results show an excellent agreement, demonstrating the accuracy of the matrix method.

  2. Experimental and numerical characterization of the sound pressure in standing wave acoustic levitators.

    PubMed

    Stindt, A; Andrade, M A B; Albrecht, M; Adamowski, J C; Panne, U; Riedel, J

    2014-01-01

    A novel method for predictions of the sound pressure distribution in acoustic levitators is based on a matrix representation of the Rayleigh integral. This method allows for a fast calculation of the acoustic field within the resonator. To make sure that the underlying assumptions and simplifications are justified, this approach was tested by a direct comparison to experimental data. The experimental sound pressure distributions were recorded by high spatially resolved frequency selective microphone scanning. To emphasize the general applicability of the two approaches, the comparative studies were conducted for four different resonator geometries. In all cases, the results show an excellent agreement, demonstrating the accuracy of the matrix method.

  3. Equivalent threshold sound pressure levels (ETSPL) for Interacoustics DD 45 supra-aural audiometric earphones.

    PubMed

    Poulsen, Torben

    2010-11-01

    This paper describes the determination and results of pure-tone equivalent threshold sound pressure levels for the Interacoustics DD 45 audiometric earphone equipped with standard Model 51 cushions. The size and shape of the DD 45 transducer resembles the classic Telephonics TDH 39 earphone. Pure-tone hearing threshold measurements were performed for both ears of 29 test subjects. All audiometric frequencies from 125 to 8000 Hz were used. The data are intended for inclusion in future standardized reference equivalent threshold sound pressure levels. The results show that the DD 45 may be a good substitute for the THD 39 without the traditional 5-dB problem at 6000 Hz.

  4. The Effect of Superior Semicircular Canal Dehiscence on Intracochlear Sound Pressures

    NASA Astrophysics Data System (ADS)

    Nakajima, Hideko Heidi; Pisano, Dominic V.; Merchant, Saumil N.; Rosowski, John J.

    2011-11-01

    Semicircular canal dehiscence (SCD) is a pathological opening in the bony wall of the inner ear that can result in conductive hearing loss. The hearing loss is variable across patients, and the precise mechanism and source of variability is not fully understood. We use intracochlear sound pressure measurements in cadaveric preparations to study the effects of SCD size. Simultaneous measurement of basal intracochlear sound pressures in scala vestibuli (SV) and scala tympani (ST) quantifies the complex differential pressure across the cochlear partition, the stimulus that excites the partition. Sound-induced pressures in SV and ST, as well as stapes velocity and ear-canal pressure are measured simultaneously for various sizes of SCD followed by SCD patching. At low frequencies (<600 Hz) our results show that SCD decreases the pressure in both SV and ST, as well as differential pressure, and these effects become more pronounced as dehiscence size is increased. For frequencies above 1 kHz, the smallest pinpoint dehiscence can have the larger effect on the differential pressure in some ears. These effects due to SCD are reversible by patching the dehiscence.

  5. Hearing with an atympanic ear: good vibration and poor sound-pressure detection in the royal python, Python regius.

    PubMed

    Christensen, Christian Bech; Christensen-Dalsgaard, Jakob; Brandt, Christian; Madsen, Peter Teglberg

    2012-01-15

    Snakes lack both an outer ear and a tympanic middle ear, which in most tetrapods provide impedance matching between the air and inner ear fluids and hence improve pressure hearing in air. Snakes would therefore be expected to have very poor pressure hearing and generally be insensitive to airborne sound, whereas the connection of the middle ear bone to the jaw bones in snakes should confer acute sensitivity to substrate vibrations. Some studies have nevertheless claimed that snakes are quite sensitive to both vibration and sound pressure. Here we test the two hypotheses that: (1) snakes are sensitive to sound pressure and (2) snakes are sensitive to vibrations, but cannot hear the sound pressure per se. Vibration and sound-pressure sensitivities were quantified by measuring brainstem evoked potentials in 11 royal pythons, Python regius. Vibrograms and audiograms showed greatest sensitivity at low frequencies of 80-160 Hz, with sensitivities of -54 dB re. 1 m s(-2) and 78 dB re. 20 μPa, respectively. To investigate whether pythons detect sound pressure or sound-induced head vibrations, we measured the sound-induced head vibrations in three dimensions when snakes were exposed to sound pressure at threshold levels. In general, head vibrations induced by threshold-level sound pressure were equal to or greater than those induced by threshold-level vibrations, and therefore sound-pressure sensitivity can be explained by sound-induced head vibration. From this we conclude that pythons, and possibly all snakes, lost effective pressure hearing with the complete reduction of a functional outer and middle ear, but have an acute vibration sensitivity that may be used for communication and detection of predators and prey.

  6. Mean tracheal sound energy during sleep is related to daytime blood pressure.

    PubMed

    Nakano, Hiroshi; Hirayama, Kenji; Sadamitsu, Yumiko; Shin, Shizue; Iwanaga, Tomoaki

    2013-09-01

    The pathological role of snoring independent of obstructive sleep apnea remains under debate. The authors hypothesized that snoring sound intensity, as assessed by mean tracheal sound energy (Leq) during sleep, is related to daytime blood pressure. Retrospective analysis of clinical records and polysomnography data. Sleep laboratory at a national hospital in Japan. Consecutive patients who underwent diagnostic polysomnography with suspicion of sleep apnea between January 2005 and December 2009 (n = 1,118). Not applicable. Leq was calculated from tracheal sound spectra recorded every 0.2 sec during polysomnography. Daytime high blood pressure (HBP) was defined as taking antihypertensive drugs or having a systolic blood pressure ≥ 140 mm Hg or a diastolic blood pressure ≥ 90 mmHg at the patient's first clinical visit. Patient age, sex, body mass index, apnea-hypopnea index, alcohol consumption, and smoking were considered as confounders. Leq during sleep was associated with HBP after adjusting for all confounding factors (n = 1,074, P = 0.00019). This association was demonstrated even in nonapneic nonobese patients (n = 232, P = 0.012). The association between snoring intensity, as assessed by mean sound energy, and blood pressure suggests a pathological role for heavy snoring. Further study in a general population is warranted.

  7. Nonlinearity in eardrum vibration as a function of frequency and sound pressure.

    PubMed

    Aerts, J R M; Dirckx, J J J

    2010-05-01

    It is generally accepted that the middle ear acts mainly as a linear system for sound pressures up to 130 dB SPL in the auditory frequency range. However, at quasi-static pressure loads a strong nonlinear response has been demonstrated. Consequently, small nonlinear distortions may also be present in the middle ear response in the auditory frequency range. A new measurement method was developed to quickly determine vibration response, nonlinear distortions and noise level of acoustically driven biomechanical systems. Specially designed multisines are used for the excitation of the test system. The method is applied on a gerbil eardrum for sound pressures ranging from 90 to 120 dB SPL and for frequencies ranging from 125 Hz to 16 kHz. The experiments show that nonlinear distortions rise above noise level at a sound pressure of 96 dB SPL, and they grow as sound pressure increases. Post-mortem changes in the middle ear influence the nonlinear distortions rapidly until a stabilization occurs after approximately 3h. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  8. Coding of sound pressure level in the barn owl's auditory nerve.

    PubMed

    Köppl, C; Yates, G

    1999-11-01

    Rate-intensity functions, i.e., the relation between discharge rate and sound pressure level, were recorded from single auditory nerve fibers in the barn owl. Differences in sound pressure level between the owl's two ears are known to be an important cue in sound localization. One objective was therefore to quantify the discharge rates of auditory nerve fibers, as a basis for higher-order processing of sound pressure level. The second aim was to investigate the rate-intensity functions for cues to the underlying cochlear mechanisms, using a model developed in mammals. Rate-intensity functions at the most sensitive frequency mostly showed a well-defined breakpoint between an initial steep segment and a progressively flattening segment. This shape has, in mammals, been convincingly traced to a compressive nonlinearity in the cochlear mechanics, which in turn is a reflection of the cochlear amplifier enhancing low-level stimuli. The similarity of the rate-intensity functions of the barn owl is thus further evidence for a similar mechanism in birds. An interesting difference from mammalian data was that this compressive nonlinearity was not shared among fibers of similar characteristic frequency, suggesting a different mechanism with a more locally differentiated operation than in mammals. In all fibers, the steepest change in discharge rate with rising sound pressure level occurred within 10-20 dB of their respective thresholds. Because the range of neural thresholds at any one characteristic frequency is small in the owl, auditory nerve fibers were collectively most sensitive for changes in sound pressure level within approximately 30 dB of the best thresholds. Fibers most sensitive to high frequencies (>6-7 kHz) showed a smaller increase of rate above spontaneous discharge rate than did lower-frequency fibers.

  9. External and middle ear sound pressure distribution and acoustic coupling to the tympanic membrane.

    PubMed

    Bergevin, Christopher; Olson, Elizabeth S

    2014-03-01

    Sound energy is conveyed to the inner ear by the diaphanous, cone-shaped tympanic membrane (TM). The TM moves in a complex manner and transmits sound signals to the inner ear with high fidelity, pressure gain, and a short delay. Miniaturized sensors allowing high spatial resolution in small spaces and sensitivity to high frequencies were used to explore how pressure drives the TM. Salient findings are: (1) A substantial pressure drop exists across the TM, and varies in frequency from ∼10 to 30 dB. It thus appears reasonable to approximate the drive to the TM as being defined solely by the pressure in the ear canal (EC) close to the TM. (2) Within the middle ear cavity (MEC), spatial variations in sound pressure could vary by more than 20 dB, and the MEC pressure at certain locations/frequencies was as large as in the EC. (3) Spatial variations in pressure along the TM surface on the EC-side were typically less than 5 dB up to 50 kHz. Larger surface variations were observed on the MEC-side.

  10. External and middle ear sound pressure distribution and acoustic coupling to the tympanic membrane

    PubMed Central

    Bergevin, Christopher; Olson, Elizabeth S.

    2014-01-01

    Sound energy is conveyed to the inner ear by the diaphanous, cone-shaped tympanic membrane (TM). The TM moves in a complex manner and transmits sound signals to the inner ear with high fidelity, pressure gain, and a short delay. Miniaturized sensors allowing high spatial resolution in small spaces and sensitivity to high frequencies were used to explore how pressure drives the TM. Salient findings are: (1) A substantial pressure drop exists across the TM, and varies in frequency from ∼10 to 30 dB. It thus appears reasonable to approximate the drive to the TM as being defined solely by the pressure in the ear canal (EC) close to the TM. (2) Within the middle ear cavity (MEC), spatial variations in sound pressure could vary by more than 20 dB, and the MEC pressure at certain locations/frequencies was as large as in the EC. (3) Spatial variations in pressure along the TM surface on the EC-side were typically less than 5 dB up to 50 kHz. Larger surface variations were observed on the MEC-side. PMID:24606269

  11. Examination of bone-conducted transmission from sound field excitation measured by thresholds, ear-canal sound pressure, and skull vibrations.

    PubMed

    Reinfeldt, Sabine; Stenfelt, Stefan; Good, Tobias; Håkansson, Bo

    2007-03-01

    Bone conduction (BC) relative to air conduction (AC) sound field sensitivity is here defined as the perceived difference between a sound field transmitted to the ear by BC and by AC. Previous investigations of BC-AC sound field sensitivity have used different estimation methods and report estimates that vary by up to 20 dB at some frequencies. In this study, the BC-AC sound field sensitivity was investigated by hearing threshold shifts, ear canal sound pressure measurements, and skull bone vibrations measured with an accelerometer. The vibration measurement produced valid estimates at 400 Hz and below, the threshold shifts produced valid estimates at 500 Hz and above, while the ear canal sound pressure measurements were found erroneous for estimating the BC-AC sound field sensitivity. The BC-AC sound field sensitivity is proposed, by combining the present result with others, as frequency independent at 50 to 60 dB at frequencies up to 900 Hz. At higher frequencies, it is frequency dependent with minima of 40 to 50 dB at 2 and 8 kHz, and a maximum of 50 to 60 dB at 4 kHz. The BC-AC sound field sensitivity is the theoretical limit of maximum attenuation achievable with ordinary hearing protection devices.

  12. Sound

    NASA Astrophysics Data System (ADS)

    Capstick, J. W.

    2013-01-01

    1. The nature of sound; 2. Elasticity and vibrations; 3. Transverse waves; 4. Longitudinal waves; 5. Velocity of longitudinal waves; 6. Reflection and refraction. Doppler's principle; 7. Interference. Beats. Combination tones; 8. Resonance and forced vibrations; 9. Quality of musical notes; 10. Organ pipes; 11. Rods. Plates. Bells; 12. Acoustical measurements; 13. The phonograph, microphone and telephone; 14. Consonance; 15. Definition of intervals. Scales. Temperament; 16. Musical instruments; 17. Application of acoustical principles to military purposes; Questions; Answers to questions; Index.

  13. 16 CFR § 1500.47 - Method for determining the sound pressure level produced by toy caps.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Method for determining the sound pressure level produced by toy caps. § 1500.47 Section § 1500.47 Commercial Practices CONSUMER PRODUCT SAFETY... ENFORCEMENT REGULATIONS § 1500.47 Method for determining the sound pressure level produced by toy caps. (a...

  14. A tomographic visualization of electric discharge sound fields in atmospheric pressure plasma using laser diffraction

    NASA Astrophysics Data System (ADS)

    Nakamiya, Toshiyuki; Mitsugi, Fumiaki; Iwasaki, Yoichiro; Ikegami, Tomoaki; Tsuda, Ryoichi; Sonoda, Yoshito; Danuta Stryczewska, Henryka

    2013-02-01

    The phase modulation of transparent gas can be detected using Fraunhofer diffraction technique, which we call optical wave microphone (OWM). The OWM is suitable for the detection of sonic wave from audible sound to ultrasonic wave. Because this technique has no influence on sound field or electric field during the measurement, we have applied it to the sound detection for the electric discharges. There is almost no research paper that uses the discharge sound to examine the electrical discharge phenomenon. Two-dimensional visualization of the sound field using the OWM is also possible when the computerized tomography (CT) is combined. In this work, coplanar dielectric barrier discharge sin different gases of Ar, N2, He were characterized via the OWM as well as applied voltage and discharge current. This is the first report to investigate the influence of the type of the atmospheric gas on the two-dimensional sound field distribution for the coplanar dielectric barrier discharge using the OWM with CT. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.

  15. Cuffless and Continuous Blood Pressure Estimation from the Heart Sound Signals

    PubMed Central

    Peng, Rong-Chao; Yan, Wen-Rong; Zhang, Ning-Ling; Lin, Wan-Hua; Zhou, Xiao-Lin; Zhang, Yuan-Ting

    2015-01-01

    Cardiovascular disease, like hypertension, is one of the top killers of human life and early detection of cardiovascular disease is of great importance. However, traditional medical devices are often bulky and expensive, and unsuitable for home healthcare. In this paper, we proposed an easy and inexpensive technique to estimate continuous blood pressure from the heart sound signals acquired by the microphone of a smartphone. A cold-pressor experiment was performed in 32 healthy subjects, with a smartphone to acquire heart sound signals and with a commercial device to measure continuous blood pressure. The Fourier spectrum of the second heart sound and the blood pressure were regressed using a support vector machine, and the accuracy of the regression was evaluated using 10-fold cross-validation. Statistical analysis showed that the mean correlation coefficients between the predicted values from the regression model and the measured values from the commercial device were 0.707, 0.712, and 0.748 for systolic, diastolic, and mean blood pressure, respectively, and that the mean errors were less than 5 mmHg, with standard deviations less than 8 mmHg. These results suggest that this technique is of potential use for cuffless and continuous blood pressure monitoring and it has promising application in home healthcare services. PMID:26393591

  16. Measurement of sound velocities in shock-compressed tin under pressures up to 150 GPa

    NASA Astrophysics Data System (ADS)

    Zhernokletov, Mikhail; Kovalev, Alexey; Komissarov, Vladimir; Zocher, Marvin; Cherne, Frank

    2009-06-01

    Tin has a complex phase diagram, which can be explained by presence of structural phase transitions. The fracture in the dependence of sound velocity on pressure is caused by structural transitions in shock-compressed substance. Therefore, basing on measurement of sound velocities, it is possible to reveal phase transitions of substance along shock adiabat, including its melting. The results of different authors give the melting range of tin from 35 up to 93 GPa. In this work tin samples with initial density of 7.28 g/cm^3 were loaded with use of HE-based generators of shock waves. In the pressure range of 30-150 GPa, sound velocity in tin was measured by the method of overtaking release with use of the optical gauges and the indicator liquids: carbogal, tetrachlormethane, and bromoform. Up to shock compression pressures of about 35 GPa, sound velocity was measured by the method of oncoming release with use of piezoresistive manganin-based gauges. The obtained data testifies that the melting range of tin is ˜6390 GPa.

  17. Measurement of Sound Velocities in Shock-Compressed Tin Under Pressures up to 150 GPa

    NASA Astrophysics Data System (ADS)

    Zhernokletov, M. V.; Kovalev, A. E.; Komissarov, V. V.; Zocher, M. A.; Cherne, F. J.

    2009-12-01

    Sound velocity in shock-compressed tin was measured over the pressure range of 31-138 GPa by the overtake method with using indicator liquids. Photodiode-based optical gauges were used to record luminescence of the liquid indicators. For shock compressions of 5-18 GPa, the sound velocity in tin was measured with manganin gauges by determining the oncoming release wave in the tin. The experimental data were compared to calculated results and data obtained by other authors. According to data obtained in this work, tin melts on the hugoniot between ˜63-90 GPa.

  18. Sound produced by an oscillating arc in a high-pressure gas

    NASA Astrophysics Data System (ADS)

    Popov, Fedor K.; Shneider, Mikhail N.

    2017-08-01

    We suggest a simple theory to describe the sound generated by small periodic perturbations of a cylindrical arc in a dense gas. Theoretical analysis was done within the framework of the non-self-consistent channel arc model and supplemented with time-dependent gas dynamic equations. It is shown that an arc with power amplitude oscillations on the order of several percent is a source of sound whose intensity is comparable with external ultrasound sources used in experiments to increase the yield of nanoparticles in the high pressure arc systems for nanoparticle synthesis.

  19. Near Noise Field of a Jet-engine Exhaust II : Cross Correlation of Sound Pressures

    NASA Technical Reports Server (NTRS)

    Callaghan, Edmund E; Howes, Walton L; Coles, Willard D

    1956-01-01

    Pressure cross correlations were obtained over a range of jet velocities both longitudinally and laterally for the overall sound pressure and for several frequency bands. The region of positive correlation was found to increase with distance downstream of the nozzle exit and was greater for lateral than for longitudinal correlations. In general, little change in the correlation curves was found as a function of jet velocity or frequency band width. Measurements made with a fixed and a movable microphone in a plate showed correlations similar to the free-field results. The results are interpreted in terms of pressure loads on surfaces.

  20. Sound pressure distribution and power flow within the gerbil ear canal from 100 Hz to 80 kHz.

    PubMed

    Ravicz, Michael E; Olson, Elizabeth S; Rosowski, John J

    2007-10-01

    Sound pressure was mapped in the bony ear canal of gerbils during closed-field sound stimulation at frequencies from 0.1 to 80 kHz. A 1.27-mm-diam probe-tube microphone or a 0.17-mm-diam fiber-optic miniature microphone was positioned along approximately longitudinal trajectories within the 2.3-mm-diam ear canal. Substantial spatial variations in sound pressure, sharp minima in magnitude, and half-cycle phase changes occurred at frequencies >30 kHz. The sound frequencies of these transitions increased with decreasing distance from the tympanic membrane (TM). Sound pressure measured orthogonally across the surface of the TM showed only small variations at frequencies below 60 kHz. Hence, the ear canal sound field can be described fairly well as a one-dimensional standing wave pattern. Ear-canal power reflectance estimated from longitudinal spatial variations was roughly constant at 0.2-0.5 at frequencies between 30 and 45 kHz. In contrast, reflectance increased at higher frequencies to at least 0.8 above 60 kHz. Sound pressure was also mapped in a microphone-terminated uniform tube-an "artificial ear." Comparison with ear canal sound fields suggests that an artificial ear or "artificial cavity calibration" technique may underestimate the in situ sound pressure by 5-15 dB between 40 and 60 kHz.

  1. Interpretation of Helioseismic Travel Times. Sensitivity to Sound Speed, Pressure, Density, and Flows

    NASA Astrophysics Data System (ADS)

    Burston, Raymond; Gizon, Laurent; Birch, Aaron C.

    2015-12-01

    Time-distance helioseismology uses cross-covariances of wave motions on the solar surface to determine the travel times of wave packets moving from one surface location to another. We review the methodology to interpret travel-time measurements in terms of small, localised perturbations to a horizontally homogeneous reference solar model. Using the first Born approximation, we derive and compute 3D travel-time sensitivity (Fréchet) kernels for perturbations in sound-speed, density, pressure, and vector flows. While kernels for sound speed and flows had been computed previously, here we extend the calculation to kernels for density and pressure, hence providing a complete description of the effects of solar dynamics and structure on travel times. We treat three thermodynamic quantities as independent and do not assume hydrostatic equilibrium. We present a convenient approach to computing damped Green's functions using a normal-mode summation. The Green's function must be computed on a wavenumber grid that has sufficient resolution to resolve the longest lived modes. The typical kernel calculations used in this paper are computer intensive and require on the order of 600 CPU hours per kernel. Kernels are validated by computing the travel-time perturbation that results from horizontally-invariant perturbations using two independent approaches. At fixed sound-speed, the density and pressure kernels are approximately related through a negative multiplicative factor, therefore implying that perturbations in density and pressure are difficult to disentangle. Mean travel-times are not only sensitive to sound-speed, density and pressure perturbations, but also to flows, especially vertical flows. Accurate sensitivity kernels are needed to interpret complex flow patterns such as convection.

  2. Development for sound velocity and density measurements of liquid metal at high pressures

    NASA Astrophysics Data System (ADS)

    Terasaki, H.; Nishida, K.; Urakawa, S.; Uesugi, K.; Takubo, Y.; Kuwabara, S.; Nakatsuka, A.; Hoshino, M.; Kono, Y.; Higo, Y.; Kondo, T.

    2012-12-01

    Sound velocity and density of liquid Fe-alloys under high pressure is quite important physical property to estimate the amount of light elements in the terrestrial core from the seismic data. Here, we have developed the system for simultaneous measurement of sound velocity and density combined with X-ray tomography technique at high pressure and temperature. High pressure experiments were performed using 80-ton uni-axial press (Urakawa et al. 2010) installed at X-ray computed micro-tomography (CT) beamline (BL20B2), SPring-8 synchrotron radiation facility. High pressure was generated using opposed-type cupped anvils. We measured the sound velocity and density of solid FeSi at room temperature and those of solid and liquid Ni-S at high temperature. Experimental pressure was obtained from the volume of h-BN. CT measurement was carried out by rotating the press from 0 to 180o with 0.2-0.3o steps. Monochromatized X-ray of 51 keV was used. Density was determined by using X-ray absorption method based on the X-ray radiograph image. The sample thickness for the X-ray path can be directly obtained from the CT data. This is a big advantage for CT measurement. Sound velocity was measured using pulse-echo overlapping ultrasonic method. P-wave signals were generated and detected by LiNbO3 transducer attached backside of the anvil. We have successfully observed both P-wave and S-wave signals up to 1.5 GPa and 1673 K. We detected change of signal intensity and shape corresponding to melting of Ni-S sample.

  3. Stapes displacement and intracochlear pressure in response to very high level, low frequency sounds.

    PubMed

    Greene, Nathaniel T; Jenkins, Herman A; Tollin, Daniel J; Easter, James R

    2017-05-01

    The stapes is held in the oval window by the stapedial annular ligament (SAL), which restricts total peak-to-peak displacement of the stapes. Previous studies have suggested that for moderate (<130 dB SPL) sound levels intracochlear pressure (PIC), measured at the base of the cochlea far from the basilar membrane, increases directly proportionally with stapes displacement (DStap), thus a current model of impulse noise exposure (the Auditory Hazard Assessment Algorithm for Humans, or AHAAH) predicts that peak PIC will vary linearly with DStap up to some saturation point. However, no direct tests of DStap, or of the relationship with PIC during such motion, have been performed during acoustic stimulation of the human ear. In order to examine the relationship between DStap and PIC to very high level sounds, measurements of DStap and PIC were made in cadaveric human temporal bones. Specimens were prepared by mastoidectomy and extended facial recess to expose the ossicular chain. Measurements of PIC were made in scala vestibuli (PSV) and scala tympani (PST), along with the SPL in the external auditory canal (PEAC), concurrently with laser Doppler vibrometry (LDV) measurements of stapes velocity (VStap). Stimuli were moderate (∼100 dB SPL) to very high level (up to ∼170 dB SPL), low frequency tones (20-2560 Hz). Both DStap and PSV increased proportionally with sound pressure level in the ear canal up to approximately ∼150 dB SPL, above which both DStap and PSV showed a distinct deviation from proportionality with PEAC. Both DStap and PSV approached saturation: DStap at a value exceeding 150 μm, which is substantially higher than has been reported for small mammals, while PSV showed substantial frequency dependence in the saturation point. The relationship between PSV and DStap remained constant, and cochlear input impedance did not vary across the levels tested, consistent with prior measurements at lower sound levels. These results suggest that PSV sound

  4. Liquid mercury sound velocity measurements under high pressure and high temperature by picosecond acoustics in a diamond anvils cell.

    PubMed

    Decremps, F; Belliard, L; Couzinet, B; Vincent, S; Munsch, P; Le Marchand, G; Perrin, B

    2009-07-01

    Recent improvements to measure ultrasonic sound velocities of liquids under extreme conditions are described. Principle and feasibility of picosecond acoustics in liquids embedded in a diamond anvils cell are given. To illustrate the capability of these advances in the sound velocity measurement technique, original high pressure and high temperature results on the sound velocity of liquid mercury up to 5 GPa and 575 K are given. This high pressure technique will certainly be useful in several fundamental and applied problems in physics and many other fields such as geophysics, nonlinear acoustics, underwater sound, petrology or physical acoustics.

  5. The effect of superior semicircular canal dehiscence on intracochlear sound pressures.

    PubMed

    Pisano, Dominic V; Niesten, Marlien E F; Merchant, Saumil N; Nakajima, Hideko Heidi

    2012-01-01

    Semicircular canal dehiscence (SCD) is a pathological opening in the bony wall of the inner ear that can result in conductive hearing loss. The hearing loss is variable across patients, and the precise mechanism and source of variability are not fully understood. Simultaneous measurements of basal intracochlear sound pressures in scala vestibuli (SV) and scala tympani (ST) enable quantification of the differential pressure across the cochlear partition, the stimulus that excites the cochlear partition. We used intracochlear sound pressure measurements in cadaveric preparations to study the effects of SCD size. Sound-induced pressures in SV and ST, as well as stapes velocity and ear canal pressure were measured simultaneously for various sizes of SCD followed by SCD patching. Our results showed that at low frequencies (<600 Hz), SCD decreased the pressure in both SV and ST, as well as differential pressure, and these effects became more pronounced as dehiscence size was increased. Near 100 Hz, SV decreased by about 10 dB for a 0.5-mm dehiscence and by 20 dB for a 2-mm dehiscence, while ST decreased by about 8 dB for a 0.5-mm dehiscence and by 18 dB for a 2-mm dehiscence. Differential pressure decreased by about 10 dB for a 0.5-mm dehiscence and by about 20 dB for a 2-mm dehiscence at 100 Hz. In some ears, for frequencies above 1 kHz, the smallest pinpoint dehiscence had bigger effects on the differential pressure (10-dB decrease) than larger dehiscences (less than 10-dB decrease), suggesting larger hearing losses in this frequency range. These effects due to SCD were reversible by patching the dehiscence. We also showed that under certain circumstances such as SCD, stapes velocity is not related to how the ear can transduce sound across the cochlear partition because it is not directly related to the differential pressure, emphasizing that certain pathologies cannot be fully assessed by measurements such as stapes velocity.

  6. The Effect of Superior Semicircular Canal Dehiscence on Intracochlear Sound Pressures

    PubMed Central

    Pisano, Dominic V.; Niesten, Marlien E.F.; Merchant, Saumil N.; Nakajima, Hideko Heidi

    2013-01-01

    Semicircular canal dehiscence (SCD) is a pathological opening in the bony wall of the inner ear that can result in conductive hearing loss. The hearing loss is variable across patients, and the precise mechanism and source of variability are not fully understood. Simultaneous measurements of basal intracochlear sound pressures in scala vestibuli (SV) and scala tympani (ST) enable quantification of the differential pressure across the cochlear partition, the stimulus that excites the cochlear partition. We used intracochlear sound pressure measurements in cadaveric preparations to study the effects of SCD size. Sound-induced pressures in SV and ST, as well as stapes velocity and ear-canal pressure were measured simultaneously for various sizes of SCD followed by SCD patching. Our results showed that at low frequencies (<600 Hz), SCD decreased the pressure in both SV and ST, as well as differential pressure, and these effects became more pronounced as dehiscence size was increased. Near 100 Hz, SV decreased about 10 dB for a 0.5 mm dehiscence and 20 dB for a 2 mm dehiscence, while ST decreased about 8 dB for a 0.5 mm dehiscence and 18 dB for a 2mm dehiscence. Differential pressure decreased about 10 dB for a 0.5 mm dehiscence and about 20 dB for a 2 mm dehiscense at 100 Hz. In some ears, for frequencies above 1 kHz, the smallest pinpoint dehiscence had bigger effects on the differential pressure (10 dB decrease) than larger dehiscenses (less than 10 dB decrease), suggesting larger hearing losses in this frequency range. These effects due to SCD were reversible by patching the dehiscence. We also showed that under certain circumstances such as SCD, stapes velocity is not related to how the ear can transduce sound across the cochlear partition because it is not directly related to the differential pressure, emphasizing that certain pathologies cannot be fully assessed by measurements such as stapes velocity. PMID:22814034

  7. The effects of pressure and temperature on sound velocity and density of Ni-S liquid

    NASA Astrophysics Data System (ADS)

    Terasaki, H. G.; Nishida, K.; Urakawa, S.; Uesugi, K.; Kuwabara, S.; Takubo, Y.; Shimoyama, Y.; Takeuchi, A.; Suzuki, Y.; Kono, Y.; Higo, Y.; Kondo, T.

    2013-12-01

    Sound velocity and density of the core material are indispensable properties to estimate a composition in the terrestrial core comparing with the observed seismic data. Here, we report these properties of Ni-S, which corresponds to the end-member of possible core composition Fe-Ni-S, at high pressure and temperature. These properties were measured based on simultaneous measurement of sound velocity and density combined with X-ray tomography technique. The experiments were carried out at X-ray computed micro-tomography (CT) beamlines (BL20XU, BL20B2), SPring-8 synchrotron radiation facility. Monochromatized X-ray of 51 keV passed through the sample cell and detected as a radiography image using CCD camera. X-ray radiography images from 0 to 180o were measured for CT measurement by rotating the press. An 80-ton uni-axial press was used to generate high pressure with using opposed-type cupped anvils (Urakawa et al. 2010). Density was determined by using X-ray absorption method obtained from the X-ray radiograph image. The sample thickness for the X-ray path can be directly obtained from the CT data. The sample density was also determined from the volume of the sample at high pressure and temperature. P-wave sound velocity was measured using pulse-echo overlapping ultrasonic method using LiNbO3 transducer attached backside of the anvil. We have successfully measured the sound velocity and density of Ni-S up to 1.5 GPa. Comparing with the previous results of liquid Fe-S, the effect of Ni on the sound velocity is minor but that on the density can not be negligible.

  8. Diversity in sound pressure levels and estimated active space of resident killer whale vocalizations.

    PubMed

    Miller, Patrick J O

    2006-05-01

    Signal source intensity and detection range, which integrates source intensity with propagation loss, background noise and receiver hearing abilities, are important characteristics of communication signals. Apparent source levels were calculated for 819 pulsed calls and 24 whistles produced by free-ranging resident killer whales by triangulating the angles-of-arrival of sounds on two beamforming arrays towed in series. Levels in the 1-20 kHz band ranged from 131 to 168 dB re 1 microPa at 1 m, with differences in the means of different sound classes (whistles: 140.2+/-4.1 dB; variable calls: 146.6+/-6.6 dB; stereotyped calls: 152.6+/-5.9 dB), and among stereotyped call types. Repertoire diversity carried through to estimates of active space, with "long-range" stereotyped calls all containing overlapping, independently-modulated high-frequency components (mean estimated active space of 10-16 km in sea state zero) and "short-range" sounds (5-9 km) included all stereotyped calls without a high-frequency component, whistles, and variable calls. Short-range sounds are reported to be more common during social and resting behaviors, while long-range stereotyped calls predominate in dispersed travel and foraging behaviors. These results suggest that variability in sound pressure levels may reflect diverse social and ecological functions of the acoustic repertoire of killer whales.

  9. Phonon Density of States and Sound Velocities of an Iron-Nickel Alloy at High Pressure

    NASA Astrophysics Data System (ADS)

    Miller, R. A.; Jackson, J. M.; Sturhahn, W.; Murphy, C. A.

    2012-12-01

    Seismological and cosmochemical studies suggest Earth's core is primarily composed of iron with ~5 to 10 wt% nickel and some light elements [e.g., 1]. Therefore, understanding the behavior of Fe-Ni alloys at high pressure is important for interpreting seismic data and for modeling the interior of the Earth. While many studies have investigated the properties of pure Fe at high pressure, the elastic and vibrational properties of Fe-Ni alloys at high pressure are not well known. We measured sound velocities and thermodynamic properties of 95%-enriched 57Fe alloyed with 10 wt% Ni at high-pressures in a Ne pressure medium. Measurements of high statistical quality were performed with nuclear resonant inelastic x-ray scattering (NRIXS) at 3ID-B of the Advanced Photon Source [e.g., 2 & 3]. The sample volume was determined at each compression point with in-line x-ray diffraction at 3ID-B before and after each NRIXS measurement. In this contribution, we will present derived partial phonon density of states, Debye sound velocities, and compressional and shear sound velocities for Fe0.9-Ni0.1 at high-pressures. [1] McDonough, W.F. (2004): Compositional Model for the Earth's Core. Elsevier Ltd., Oxford. [2] Murphy, C.A., J.M. Jackson, W. Sturhahn, and B. Chen (2011): Melting and thermal pressure of hcp-Fe from the phonon density of states, Phys. Earth Planet. Int., doi:10.1016/j.pepi.2011.07.001. [3] Murphy, C.A., J.M. Jackson, W. Sturhahn, and B. Chen (2011): Grüneisen parameter of hcp-Fe to 171 GPa, Geophys. Res. Lett., doi:10.1029/2011GL049531.

  10. Separation of non-stationary sound fields with single layer pressure-velocity measurements.

    PubMed

    Bi, Chuan-Xing; Geng, Lin; Zhang, Xiao-Zheng

    2016-02-01

    This paper examines the feasibility of extracting the non-stationary sound field generated by a target source in the presence of disturbing source from single layer pressure-velocity measurements. Unlike the method described in a previous paper [Bi, Geng, and Zhang, J. Acoust. Soc. Am. 135(6), 3474-3482 (2014)], the proposed method allows measurements of pressure and particle velocity signals on a single plane instead of pressure signals on two planes, and the time-dependent pressure generated by the target source is extracted by a simple superposition of the measured pressure and the convolution between the measured particle velocity and the corresponding impulse response function. Because the particle velocity here is measured directly, the error caused by the finite difference approximation can be avoided, which makes it possible to perform the separation better than the previous method. In this paper, a Microflown pressure-velocity probe is used to perform the experimental measurements, and the calibration procedure of the probe in the time domain is given. The experimental results demonstrate that the proposed method is effective in extracting the desired non-stationary sound field generated by the target source from the mixed one in both time and space domains, and it obtains more accurate results than the previous method.

  11. A non-invasive approach to investigation of ventricular blood pressure using cardiac sound features.

    PubMed

    Tang, Hong; Zhang, Jinghui; Chen, Huaming; Mondal, Ashok; Park, Yongwan

    2017-02-01

    Heart sounds (HSs) are produced by the interaction of the heart valves, great vessels, and heart wall with blood flow. Previous researchers have demonstrated that blood pressure can be predicted by exploring the features of cardiac sounds. These features include the amplitude of the HSs, the ratio of the amplitude, the systolic time interval, and the spectrum of the HSs. A single feature or combinations of several features have been used for prediction of blood pressure with moderate accuracy. Experiments were conducted with three beagles under various levels of blood pressure induced by different doses of epinephrine. The HSs, blood pressure in the left ventricle and electrocardiograph signals were simultaneously recorded. A total of 31 records (18 262 cardiac beats) were collected. In this paper, 91 features in various domains are extracted and their linear correlations with the measured blood pressures are examined. These features are divided into four groups and applied individually at the input of a neural network to predict the left ventricular blood pressure (LVBP). The analysis shows that non-spectral features can track changes of the LVBP with lower standard deviation. Consequently, the non-spectral feature set gives the best prediction accuracy. The average correlation coefficient between the measured and the predicted blood pressure is 0.92 and the mean absolute error is 6.86 mmHg, even when the systolic blood pressure varies in the large range from 90 mmHg to 282 mmHg. Hence, systolic blood pressure can be accurately predicted even when using fewer HS features. This technique can be used as an alternative to real-time blood pressure monitoring and it has promising applications in home health care environments.

  12. Resonant tube for measurement of sound absorption in gases at low frequency/pressure ratios

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.; Griffin, W. A.

    1980-01-01

    The paper describes a resonant tube for measuring sound absorption in gases, with specific emphasis on the vibrational relaxation peak of N2, over a range of frequency/pressure ratios from 0.1 to 2500 Hz/atm. The experimental background losses measured in argon agree with the theoretical wall losses except at few isolated frequencies. Rigid cavity terminations, external excitation, and a differential technique of background evaluation were used to minimize spurious contributions to the background losses. Room temperature measurements of sound absorption in binary mixtures of N2-CO2 in which both components are excitable resulted in the maximum frequency/pressure ratio in Hz/atm of 0.063 + 123m for the N2 vibrational relaxation peak, where m is mole percent of added CO2; the maximum ratio for the CO2 peak was 34,500 268m where m is mole percent of added N2.

  13. Sound pressure level variations across the Pacific based on IMS data

    NASA Astrophysics Data System (ADS)

    Yamada, Tomoaki; Haralabus, Georgios; Zampolli, Mario; Heaney, Kevin

    2017-04-01

    Low frequency hydro-acoustic waves can be detected at great distances due to low attenuation of acoustic energy in the SOund Fixing And Ranging (SOFAR) channel. These waves contain both acoustic source and propagation medium information which is difficult to separate at the receiving end. This study examines sound pressure level variations across the pacific using 100 underwater controlled sources near a landward slope zone in Japan to minimize source uncertainty. The data were acquired at water-column hydrophones of the hydroacoustic station HA03 at Chile that is part of the International Monitoring System (IMS) of the Comprehensive Nuclear Test Ban Treaty. Acoustics waves were detected over 15,000 km across the Pacific and initial analysis indicates a maximum difference of the pressure level is 17 dB re. micro Pa.

  14. Comparison of measured and calculated sound pressure levels around a large horizontal axis wind turbine generator

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P.; Willshire, William L., Jr.; Hubbard, Harvey H.

    1989-01-01

    Results are reported from a large number of simultaneous acoustic measurements around a large horizontal axis downwind configuration wind turbine generator. In addition, comparisons are made between measurements and calculations of both the discrete frequency rotational harmonics and the broad band noise components. Sound pressure time histories and noise radiation patterns as well as narrow band and broadband noise spectra are presented for a range of operating conditions. The data are useful for purposes of environmental impact assessment.

  15. Measurement and analysis of 8-hour time-weighted average sound pressure levels in a vivarium decontamination facility.

    PubMed

    Pate, William; Charlton, Michael; Wellington, Carl

    2013-01-01

    Occupational noise exposure is a recognized hazard for employees working near equipment and processes that generate high levels of sound pressure. High sound pressure levels have the potential to result in temporary or permanent alteration in hearing perception. The cleaning of cages used to house laboratory research animals is a process that uses equipment capable of generating high sound pressure levels. The purpose of this research study was to assess occupational exposure to sound pressure levels for employees operating cage decontamination equipment. This study reveals the potential for overexposure to hazardous noise as defined by the Occupational Safety and Health Administration (OSHA) permissible exposure limit and consistent surpassing of the OSHA action level. These results emphasize the importance of evaluating equipment and room design when acquiring new cage decontamination equipment in order to minimize employee exposure to potentially hazardous noise pressure levels.

  16. Measurement of sound velocities of laser-shocked iron at pressures up to 800 GPa

    NASA Astrophysics Data System (ADS)

    Sakaiya, T.; Takahashi, H.; Kondo, T.; Shigemori, K.; Kadono, T.; Hironaka, Y.; Osaki, N.; Irifune, T.

    2011-12-01

    When we consider the structure of the Earth's interior, the sound velocity is one of the important physical properties of the interior materials because it can be directly compared with the seismological data which can yield the physical properties of the Earth's interior. Although it needs to measure the sound velocity of the interior material under high pressure and temperature, the sound velocity measurement of the materials on the condition over 200 GPa and 4000 K, such as the Earth's core condition, is technically difficult in static compression technique (e.g. diamond anvil cell: DAC) [1-3]. Therefore, in such higher pressure and temperature, dynamic compression technique, such as gas gun, is used. Although some works about the sound velocity of pure iron have been done by gas gun [4-6], it is not enough to discuss about the Earth's core which consists mainly of iron. We performed laser-shock experiments of iron at GEKKO-XII Laser System HIPER irradiation facility in Institute of Laser Engineering, Osaka University (ILE) [7]. The laser-shock compression can generate pressures over 1TPa, which are much higher pressures than previous works by gas gun. The sound velocities of iron were measured by side-on radiography [6]. The laser-irradiated target (Fe) is backlit with an x ray emitted from a high-Z foil (Ti) that is located along the side of the target and that is irradiated by a separate laser. The intensity distribution of the x ray transmitted through the target is imaged onto an x-ray streak camera. When the motion of the front surface and rear surface of the target is obtained from the radiograph, we can obtain the velocity of the shock and rarefaction wave. The rarefaction wave propagates the target with the sound velocity. The pressure generated by the laser-shock compression is obtained from the shock velocity and particle velocity of the target. The particle velocity is obtained from the time revolution of the front surface in the radiograph. In this

  17. An analytical model for the underwater sound pressure waveforms radiated when an offshore pile is driven.

    PubMed

    Hall, Marshall V

    2015-08-01

    An analytical model has been developed for the pile vibration and consequent sound pressure and particle velocity radiated underwater when an offshore cylindrical pile is struck by a drop hammer. The model, which is based on the coupled equations of motion for axial and radial vibration of a thin cylindrical shell, yields frequency-dependent phase velocity and attenuation of these vibrations. The amplitude of the pulse of axial and radial displacement that travels down a pile following an axial impact is described in terms of the hammer properties. Solutions are obtained for the radiated sound pressure and particle velocity, using Junger and Feit's Transform Formulation of the Pressure Field of Cylindrical Radiators [(Acoustical Society of America, New York, 1993), p. 216]. The model is applied to published data on radiated noise from offshore driving of a steel pile. The modeled pressure waveforms at 12-m horizontal range and at 9 hydrophone depths correlate significantly with the measured waveforms. The modeled pressures of the initial positive peaks (appropriately low-pass filtered) agree with data to within 1 dB. The initial negative peaks however exceed the data by up to 7 dB, and as hydrophone depth increases, the model negative peaks have a maximum at 7 m, whereas the data have a maximum at 9 m.

  18. Revisit of the relationship between the elastic properties and sound velocities at high pressures

    NASA Astrophysics Data System (ADS)

    Wang, Chenju; Xiang, Shikai; Gu, Jianbing; Kuang, Xiaoyu; Yu, Yin; Yan, Xiaozhen; Chen, Haiyan

    2014-09-01

    The second-order elastic constants and stress-strain coefficients are defined, respectively, as the second derivatives of the total energy and the first derivative of the stress with respect to strain. Since the Lagrangian and infinitesimal strain are commonly used in the two definitions above, the second-order elastic constants and stress-strain coefficients are separated into two categories, respectively. In general, any of the four physical quantities is employed to characterize the elastic properties of materials without differentiation. Nevertheless, differences may exist among them at non-zero pressures, especially high pressures. Having explored the confusing issue systemically in the present work, we find that the four quantities are indeed different from each other at high pressures and these differences depend on the initial stress applied on materials. Moreover, the various relations between the four quantities depicting elastic properties of materials and high-pressure sound velocities are also derived from the elastic wave equations. As examples, we calculated the high-pressure sound velocities of cubic tantalum and hexagonal rhenium using these nexus. The excellent agreement of our results with available experimental data suggests the general applicability of the relations.

  19. Revisit of the relationship between the elastic properties and sound velocities at high pressures

    SciTech Connect

    Wang, Chenju; Yan, Xiaozhen; Xiang, Shikai Chen, Haiyan; Gu, Jianbing; Yu, Yin; Kuang, Xiaoyu

    2014-09-14

    The second-order elastic constants and stress-strain coefficients are defined, respectively, as the second derivatives of the total energy and the first derivative of the stress with respect to strain. Since the Lagrangian and infinitesimal strain are commonly used in the two definitions above, the second-order elastic constants and stress-strain coefficients are separated into two categories, respectively. In general, any of the four physical quantities is employed to characterize the elastic properties of materials without differentiation. Nevertheless, differences may exist among them at non-zero pressures, especially high pressures. Having explored the confusing issue systemically in the present work, we find that the four quantities are indeed different from each other at high pressures and these differences depend on the initial stress applied on materials. Moreover, the various relations between the four quantities depicting elastic properties of materials and high-pressure sound velocities are also derived from the elastic wave equations. As examples, we calculated the high-pressure sound velocities of cubic tantalum and hexagonal rhenium using these nexus. The excellent agreement of our results with available experimental data suggests the general applicability of the relations.

  20. Sound Velocity Measurement of Stishovite at High Pressures up to 19 GPa

    NASA Astrophysics Data System (ADS)

    Zhou, C.; Jin, Z.; Wang, Y.; Zhang, Y.; WANG, C.

    2015-12-01

    An experimental system for measurement of the elastic wave velocities of solid polycrystalline samples at high pressures has been installed at the State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Wuhan). The ultrasonic system with LiNbO3 transducer can both generate and receive high frequency (MHz) signal. Combination with a Walker-type multianvil, the travel time through the polycrystalline sample at high pressures can be obtained. We carried out sound velocity measurements on polycrystalline stishovite up to 19 GPa at room temperature. And the experimental result shows an acoustic softening at high pressures. The experimental technique provides the offline experimental measurement of various materials to the high pressures corresponding to the Earth's mantle transition zone.

  1. Experimental constraints on the thermodynamics and sound velocities of hcp-Fe to core pressures

    NASA Astrophysics Data System (ADS)

    Murphy, Caitlin A.; Jackson, Jennifer M.; Sturhahn, Wolfgang

    2013-05-01

    We report the high-pressure thermoelastic and vibrational thermodynamic parameters for hexagonal close-packed iron (ɛ-Fe), based on nuclear resonant inelastic X-ray scattering and in situ X-ray diffraction experiments at 300 K. Long data collection times, high-energy resolution, and quasi-hydrostatic sample conditions produced a high-statistical quality data set that comprises the volume-dependent phonon density of states (DOS) of ɛ-Fe at eleven compression points. From the integrated phonon DOS, we determine the Lamb-Mössbauer factor (fLM), average force constant (Φ), and vibrational entropy (Svib) of ɛ-Fe to pressures relevant to Earth's outer core. We find fLM = 0.923 ± 0.001 at 171 GPa, suggesting restricted thermal atomic motion at large compressions. We use Φ to approximate ɛ-Fe's pressure- and temperature-dependent reduced isotopic partition function ratios (β-factors), which provide information about the partitioning behavior of iron isotopes in equilibrium processes involving solid ɛ-Fe. In addition, we use the volume dependence of Svib to determine the product of ɛ-Fe's vibrational thermal expansion coefficient and isothermal bulk modulus, which we find to be pressure-independent and equal to 5.70 ± 0.05 MPa/K at 300 K. Finally, from the low-energy region of each phonon DOS, we determine the Debye sound velocity (vD), from which we derive the compressional (vP) and shear (vS) sound velocities of ɛ-Fe. We find vD = 5.60 ± 0.06, vP = 10.11 ± 0.12, and vS = 4.99 ± 0.06 km/s at 171 GPa, thus providing a new tight constraint on the density dependence of ɛ-Fe's sound velocities to outer core pressures.

  2. Sound Pressure Levels Measured in a University Concert Band: A Risk of Noise-Induced Hearing Loss?

    ERIC Educational Resources Information Center

    Holland, Nicholas V., III

    2008-01-01

    Researchers have reported public school band directors as experiencing noise-induced hearing loss. Little research has focused on collegiate band directors and university student musicians. The present study measures the sound pressure levels generated within a university concert band and compares sound levels with the criteria set by the…

  3. Sound Pressure Levels Measured in a University Concert Band: A Risk of Noise-Induced Hearing Loss?

    ERIC Educational Resources Information Center

    Holland, Nicholas V., III

    2008-01-01

    Researchers have reported public school band directors as experiencing noise-induced hearing loss. Little research has focused on collegiate band directors and university student musicians. The present study measures the sound pressure levels generated within a university concert band and compares sound levels with the criteria set by the…

  4. Sound pressure transformations by the head and pinnae of the adult Chinchilla (Chinchilla lanigera)

    PubMed Central

    Koka, Kanthaiah; Jones, Heath G.; Thornton, Jennifer L.; Lupo, J. Eric; Tollin, Daniel J.

    2010-01-01

    There are three main cues to sound location: the interaural differences in time (ITD) and level (ILD) as well as the monaural spectral shape cues. These cues are generated by the spatial- and frequency-dependent filtering of propagating sound waves by the head and external ears. Although the chinchilla has been used for decades to study the anatomy, physiology, and psychophysics of audition, including binaural and spatial hearing, little is actually known about the sound pressure transformations by the head and pinnae and the resulting sound localization cues available to them. Here, we measured the directional transfer functions (DTFs), the directional components of the head-related transfer functions, for 9 adult chinchillas. The resulting localization cues were computed from the DTFs. In the frontal hemisphere, spectral notch cues were present for frequencies from ~6–18 kHz. In general, the frequency corresponding to the notch increased with increases in source elevation as well as in azimuth towards the ipsilateral ear. The ILDs demonstrated a strong correlation with source azimuth and frequency. The maximum ILDs were < 10 dB for frequencies < 5 kHz, and ranged from 10–30 dB for the frequencies > 5 kHz. The maximum ITDs were dependent on frequency, yielding 236 μs at 4 kHz and 336 μs at 250 Hz. Removal of the pinnae eliminated the spectral notch cues, reduced the acoustic gain and the ILDs, altered the acoustic axis, and reduced the ITDs. PMID:20971180

  5. A geospatial model of ambient sound pressure levels in the contiguous United States.

    PubMed

    Mennitt, Daniel; Sherrill, Kirk; Fristrup, Kurt

    2014-05-01

    This paper presents a model that predicts measured sound pressure levels using geospatial features such as topography, climate, hydrology, and anthropogenic activity. The model utilizes random forest, a tree-based machine learning algorithm, which does not incorporate a priori knowledge of source characteristics or propagation mechanics. The response data encompasses 270 000 h of acoustical measurements from 190 sites located in National Parks across the contiguous United States. The explanatory variables were derived from national geospatial data layers and cross validation procedures were used to evaluate model performance and identify variables with predictive power. Using the model, the effects of individual explanatory variables on sound pressure level were isolated and quantified to reveal systematic trends across environmental gradients. Model performance varies by the acoustical metric of interest; the seasonal L50 can be predicted with a median absolute deviation of approximately 3 dB. The primary application for this model is to generalize point measurements to maps expressing spatial variation in ambient sound levels. An example of this mapping capability is presented for Zion National Park and Cedar Breaks National Monument in southwestern Utah.

  6. Assessment and characterization of sound pressure levels in Portuguese neonatal intensive care units.

    PubMed

    Santos, Joana; Carvalhais, Carlos; Xavier, Ana; Silva, Manuela V

    2017-03-13

    In the NICU, systematic exposure to sound-pressure above the recommended level can affect both neonates and staff. This study aimed to evaluate the sound pressure levels in three Portuguese NICUs and the noise perceptions of staff. The measurements were performed with a sound-level meter, considering the location of the main sources of noise and the layout of the units. A questionnaire was applied to assess noise perceptions of professionals. Among the staff, 41.1% classified the environment (regarding noise) as "slightly uncomfortable"; 48.4% considered it as "acceptable." The majority (55.5%) considered "equipment" the most annoying source of noise. The results showed that noise levels were excessive in all the evaluated areas of the NICUs, exceeding international guidelines, with levels ranging between 48.7 dBA to 71.7 dBA. Overall, there is a need for more research to verify the effectiveness of some actions and strategies to reduce the effect of noise in the NICU.

  7. Acoustic mechanisms that determine the ear-canal sound pressures generated by earphones.

    PubMed

    Voss, S E; Rosowski, J J; Shera, C A; Peake, W T

    2000-03-01

    In clinical measurements of hearing sensitivity, a given earphone is assumed to produce essentially the same sound-pressure level in all ears. However, recent measurements [Voss et al., Ear and Hearing (in press)] show that with some middle-ear pathologies, ear-canal sound pressures can deviate by as much as 35 dB from the normal-ear value; the deviations depend on the earphone, the middle-ear pathology, and frequency. These pressure variations cause errors in the results of hearing tests. Models developed here identify acoustic mechanisms that cause pressure variations in certain pathological conditions. The models combine measurement-based Thévenin equivalents for insert and supra-aural earphones with lumped-element models for both the normal ear and ears with pathologies that alter the ear's impedance (mastoid bowl, tympanostomy tube, tympanic-membrane perforation, and a "high-impedance" ear). Comparison of the earphones' Thévenin impedances to the ear's input impedance with these middle-ear conditions shows that neither class of earphone acts as an ideal pressure source; with some middle-ear pathologies, the ear's input impedance deviates substantially from normal and thereby causes abnormal ear-canal pressure levels. In general, for the three conditions that make the ear's impedance magnitude lower than normal, the model predicts a reduced ear-canal pressure (as much as 35 dB), with a greater pressure reduction with an insert earphone than with a supra-aural earphone. In contrast, the model predicts that ear-canal pressure levels increase only a few dB when the ear has an increased impedance magnitude; the compliance of the air-space between the tympanic membrane and the earphone determines an upper limit on the effect of the middle-ear's impedance increase. Acoustic leaks at the earphone-to-ear connection can also cause uncontrolled pressure variations during hearing tests. From measurements at the supra-aural earphone-to-ear connection, we conclude that it

  8. Pressure Contact Sounding Data for NASA's Atmospheric Variability Experiment (AVE 3)

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.; Hill, C. K.; Turner, R. E.; Long, K. E.

    1975-01-01

    The basic rawinsonde data are described at each pressure contact from the surface to sounding termination for the 41 stations participating in the AVE III measurement program that began at 0000 GMT on February 6 and ended at 1200 GMT on February 7, 1975. Soundings were taken at 3-hour intervals during a large period of the experiment from most stations within the United States east of about 105 degrees west longitude. Methods of data processing, change in reduction scheme since the AVE II pilot experiment, and data accuracy are briefly discussed. An example of contact data is presented, and microfiche cards of all the contact data are included in the appendix. The AVE III project was conducted to better understand and establish the extent of applications for meteorological satellite sensor data through correlative ground truth experiments and to provide basic experimental data for use in studies of atmospheric scales of-motion interrelationships.

  9. Pressure contact sounding data for NASA's Atmospheric Variability Experiment (AVE 2). [rawinsondes

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.; Turner, R. E.

    1975-01-01

    The basic rawinsonde data are described at each pressure contact from the surface to sounding termination for the 54 stations participating in the AVE 2 pilot experiment. Soundings were taken at three-hour intervals from stations within the United States east of about 105 degrees west longitude. Methods of data reduction and estimates of data accuracy are discussed. Examples of the data records produced are shown. The AVE 2 pilot experiment was conducted as part of NASA's program to better understand and establish the extent of applications for meteorological satellite sensor data through correlative ground truth experiments and to provide basic experimental data for use in studies of atmospheric scales-of-motion interrelationships.

  10. Effects of coordination and pressure on sound attenuation, boson peak and elasticity in amorphous solids.

    PubMed

    DeGiuli, Eric; Laversanne-Finot, Adrien; Düring, Gustavo; Lerner, Edan; Wyart, Matthieu

    2014-08-14

    Connectedness and applied stress strongly affect elasticity in solids. In various amorphous materials, mechanical stability can be lost either by reducing connectedness or by increasing pressure. We present an effective medium theory of elasticity that extends previous approaches by incorporating the effect of compression, of amplitude e, allowing one to describe quantitative features of sound propagation, transport, the boson peak, and elastic moduli near the elastic instability occurring at a compression ec. The theory disentangles several frequencies characterizing the vibrational spectrum: the onset frequency where strongly-scattered modes appear in the vibrational spectrum, the pressure-independent frequency ω* where the density of states displays a plateau, the boson peak frequency ωBP found to scale as , and the Ioffe-Regel frequency ωIR where scattering length and wavelength become equal. We predict that sound attenuation crosses over from ω(4) to ω(2) behaviour at ω0, consistent with observations in glasses. We predict that a frequency-dependent length scale ls(ω) and speed of sound ν(ω) characterize vibrational modes, and could be extracted from scattering data. One key result is the prediction of a flat diffusivity above ω0, in agreement with previously unexplained observations. We find that the shear modulus does not vanish at the elastic instability, but drops by a factor of 2. We check our predictions in packings of soft particles and study the case of covalent networks and silica, for which we predict ωIR ≈ ωBP. Overall, our approach unifies sound attenuation, transport and length scales entering elasticity in a single framework where disorder is not the main parameter controlling the boson peak, in agreement with observations. This framework leads to a phase diagram where various glasses can be placed, connecting microscopic structure to vibrational properties.

  11. Density and sound velocity of Fe-S liquids at high pressures

    NASA Astrophysics Data System (ADS)

    Jing, Z.; Sakamaki, T.; Yu, T.; Kono, Y.; Wang, Y.; Park, C.; Shen, G.

    2011-12-01

    Liquid iron is the dominant component in the Earth's outer core and possibly the cores (or outer cores) of other terrestrial planets like Moon, Mars, and Mercury. Seismological and geochemical observations suggest that light elements such as S, C, O, Si, H, etc may be present in the liquid cores. In order to constrain the abundances of light elements and understand their effects on the structure, dynamics, and evolution of planetary cores, it is crucial to determine the equation of state for Fe-light element alloying liquids under core conditions. However, density data on liquid Fe-light element alloys at core pressures are very limited and no sound velocity or bulk modulus data are available for these liquids at high pressures. This makes it difficult to extrapolate the equation of state to core pressures. As a result, density data on solid Fe alloys are often used in the literature to compare with seismological observations by making corrections for the volume of melting. In this study, we extend the density dataset for Fe-S liquids by measuring the density of liquid iron with 19wt% sulfur and 27wt% sulfur using the X-ray absorption technique in a DIA-type multianvil apparatus up to 7 GPa and 2173 K. Ion chambers and 2D X-ray radiographic images were used to measure intensities of the incident and transmitted monochromatic X-rays, with the photon energy optimized at 40 keV. The density was then determined from the Beer-Lambert law using the mass absorption coefficients. We have also developed techniques to directly measure the ultrasonic sound velocities in these liquids up to 5 GPa and 1773 K using a Paris-Edinburgh cell. The sound velocity was determined by measuring the travel time difference between the sample echo and the buffer rod echo using a waveform generator and a digital oscilloscope and by measuring the sample thickness using X-ray radiographic images. The combination of density and sound velocity data can provide tight constraints on the equation of

  12. Measurement of sound speed vs. depth in South Pole ice: pressure waves and shear waves

    SciTech Connect

    IceCube Collaboration; Klein, Spencer

    2009-06-04

    We have measured the speed of both pressure waves and shear waves as a function of depth between 80 and 500 m depth in South Pole ice with better than 1% precision. The measurements were made using the South Pole Acoustic Test Setup (SPATS), an array of transmitters and sensors deployed in the ice at the South Pole in order to measure the acoustic properties relevant to acoustic detection of astrophysical neutrinos. The transmitters and sensors use piezoceramics operating at {approx}5-25 kHz. Between 200 m and 500 m depth, the measured profile is consistent with zero variation of the sound speed with depth, resulting in zero refraction, for both pressure and shear waves. We also performed a complementary study featuring an explosive signal propagating vertically from 50 to 2250 m depth, from which we determined a value for the pressure wave speed consistent with that determined for shallower depths, higher frequencies, and horizontal propagation with the SPATS sensors. The sound speed profile presented here can be used to achieve good acoustic source position and emission time reconstruction in general, and neutrino direction and energy reconstruction in particular. The reconstructed quantities could also help separate neutrino signals from background.

  13. Loudness discomfort level for speech: comparison of two instructional sets for saturation sound pressure level selection.

    PubMed

    Beattie, R C; Svihovec, D A; Carmen, R E; Kunkel, H A

    1980-01-01

    This study was undertaken to compare the speech loudness discomfort levels (LDL's) with two instructional sets which have been proposed for saturation sound pressure level selection of hearing aids. The phraseology recommended by McCandless and by Berger was presented to normal-hearing and hearing-impaired listeners. The normal-hearing subjects obtained mean LDL's of 94.6 and 111.9 dB SPL for these respective instructions, which was statistically significant. The hearing-impaired listeners also showed LDL's with Berger's instructions (114.7 dB SPL) to be significantly higher than with McCandless' instructional set (109.3 dB SPL). Consequently, this investigation suggests that these two instructional sets may lead to substantially different saturation sound pressure levels. Further studies are needed to determine the most appropriate phraseology for LDL measurement, including the assessment of speech intelligibility at various saturation sound pressure levels. Another instructional set was constructed which (1) includes an explanation to patients of the purpose and importance of the test, (2) requests listeners to indicate the upper level they are "willing" to listen as opposed to the level they are "able" to listen, (3) instructs patients to search thoroughly around their LDL before making a final judgment, and (4) contains a statement that the LDL should be made with the understanding that the speech could be listened to for a period of time. Whatever instructions are used, clinicians are advised to interpret their LDL's very cautiously until validational studies are available.

  14. Broadband Sound Pressure Field Characteristics of Marine Seismic Sources Used by R/V Polarstern

    NASA Astrophysics Data System (ADS)

    Breitzke, M.; Boebel, O.; El Naggar, S.; Jokat, W.; Kuhn, G.; Niessen, F.; Schenke, H.; Werner, B.; Diebold, J.

    2006-05-01

    Single airguns and airgun arrays of different size and volume are used as sound sources for scientific marine seismic reflection and refraction surveys conducted by R/V Polarstern in the Arctic and Antarctic Ocean. To ensure that these research activities do not affect marine wildlife and particularly marine mammals in the Antarctic Treaty Area south of 60°S knowledge of the sound pressure field of the seismic sources is essential. Therefore, a broadband marine seismic source characterization study was conducted at the Heggernes Acoustic Range in the Herdlefjord, Norway in October 2003. The objectives were (1) to determine the spatial distribution of the sound pressure levels emitted by Polarstern's seismic sources, (2) to compute the source levels assuming a spherical amplitude decay, (3) to determine mitigation radii, within which at least some species of marine mammals might possibly experience behavioral or physiological disturbance due to the received sound pressure levels. The thresholds currently in use to determine mitigation radii are 160 dBRMS re 1 μPa for potential behavioral disturbance and 180 dBRMS re 1 μPa for potential physiological and hearing effects like temporary threshold shifts. To determine the spatial distribution of the sound pressure levels each airgun (array) was shot along a line of 2- 3 km length running between 2 hydrophone chains with receivers in 35, 100, 198 and 267 m depth. A GI-Gun (2.4 l), a G-Gun (8.5 l) and a Bolt PAR CT800 (32.8 l) were deployed as single sources, and 3 GI-Guns (7.4 l), 3 G-Guns (25.6 l) and 8 VLF-Guns (24 l) as arrays. The measurements are complemented by a modeling approach for an 8 G-Gun (68.2 l) and 8 G-Gun+1 Bolt PAR CT800 array (100.1 l). The data analysis includes a determination of peak-peak, zero-peak and RMS-amplitudes, sound exposure levels and amplitude spectra as function of source-receiver distance. The amplitude vs distance graphs, analyzed for the 4 hydrophone depths, show the typical

  15. Sound Pressures and Correlations of Noise on the Fuselage of a Jet Aircraft in Flight

    NASA Technical Reports Server (NTRS)

    Shattuck, Russell D.

    1961-01-01

    Tests were conducted at altitudes of 10,000, 20,000, and 30,000 feet at speeds of Mach 0.4, 0.6, and O.8. It was found that the sound pressure levels on the aft fuselage of a jet aircraft in flight can be estimated using an equation involving the true airspeed and the free air density. The cross-correlation coefficient over a spacing of 2.5 feet was generalized with Strouhal number. The spectrum of the noise in flight is comparatively flat up to 10,000 cycles per second.

  16. Intersubject variability of real-ear sound pressure level: conventional and insert earphones.

    PubMed

    Valente, M; Potts, L G; Valente, M; Vass, W; Goebel, J

    1994-11-01

    Measures of the sound pressure level (SPL) near the eardrum were determined at discrete frequencies between 500 and 4000 Hz on 50 ears using TDH-39P and ER-3A earphones with the attenuator of an audiometer fixed at 90 dB HL. Results revealed significant differences in the measured SPL between the two earphones at all test frequencies. Results also revealed large intersubject differences in the SPL measured near the eardrum for both earphones. The results of this study highlight the large intersubject variability associated with measuring the SPL at the eardrum and point out the difficulty in accurately predicting individual performance from averaged group data.

  17. A phase comparison technique for sound velocity measurement in strongly dissipative liquids under pressure.

    PubMed

    Khelladi, Hassina; Plantier, Frédéric; Daridon, Jean Luc

    2010-08-01

    An accurate technique for the sound velocity measurement in strongly dissipative liquids is elaborated. This technique is based upon high sensitive phase detection. Each medium, at a given temperature and pressure, is characterized by a specific phase shift due to the propagation of the ultrasonic wave within the analyzed medium. By tuning the insonation frequency of the ultrasonic signal, a succession of consecutive nulls of the output dc voltage generated by the phase detector is observed. Thus from the obtained series of frequency values, the sound velocity is computed. Numerous organic liquids, such as alcohols and alkanes, have been used to validate this experimental procedure. As the developed method is well suited for the sound velocity measurement in strongly dissipative liquids, measurements of compressional wave velocity in heavy oil are also carried out over the temperature range 10 degrees C to 50 degrees C. The experimental results agree well with those found in the literature. The accuracy of the developed method is estimated at about +/-0.3%.

  18. Sound pressure transformations by the head and pinnae of the adult Chinchilla (Chinchilla lanigera).

    PubMed

    Koka, Kanthaiah; Jones, Heath G; Thornton, Jennifer L; Lupo, J Eric; Tollin, Daniel J

    2011-02-01

    There are three main cues to sound location: the interaural differences in time (ITD) and level (ILD) as well as the monaural spectral shape cues. These cues are generated by the spatial- and frequency-dependent filtering of propagating sound waves by the head and external ears. Although the chinchilla has been used for decades to study the anatomy, physiology, and psychophysics of audition, including binaural and spatial hearing, little is actually known about the sound pressure transformations by the head and pinnae and the resulting sound localization cues available to them. Here, we measured the directional transfer functions (DTFs), the directional components of the head-related transfer functions, for 9 adult chinchillas. The resulting localization cues were computed from the DTFs. In the frontal hemisphere, spectral notch cues were present for frequencies from ∼6-18 kHz. In general, the frequency corresponding to the notch increased with increases in source elevation as well as in azimuth towards the ipsilateral ear. The ILDs demonstrated a strong correlation with source azimuth and frequency. The maximum ILDs were <10 dB for frequencies <5 kHz, and ranged from 10-30 dB for the frequencies >5 kHz. The maximum ITDs were dependent on frequency, yielding 236 μs at 4 kHz and 336 μs at 250 Hz. Removal of the pinnae eliminated the spectral notch cues, reduced the acoustic gain and the ILDs, altered the acoustic axis, and reduced the ITDs.

  19. Sound Velocities of Iron-Nickel and Iron-Nickel-Silicon Alloys at High Pressure

    NASA Astrophysics Data System (ADS)

    Miller, R. A.; Jackson, J. M.; Sturhahn, W.; Zhao, J.; Murphy, C. A.

    2014-12-01

    Seismological and cosmochemical studies suggest Earth's core is primarily composed of iron with ~5 to 10 wt% nickel and some light elements [e.g. 1]. To date, the concentration of nickel and the amount and identity of light elements remain poorly constrained due in part to the difficulty of conducting experimental measurements at core conditions. The vibrational properties of a variety iron alloys paired with seismic observations can help better constrain the composition of the core. We directly measured the partial phonon density of states of bcc- and hcp-structured Fe0.9Ni0.1 and Fe0.85Ni0.1Si0.05 at high pressures. The samples were compressed using a panoramic diamond anvil cell. A subset of the experiments were conducted using neon as a pressure transmitting medium. Measurements of high statistical quality were performed with nuclear resonant inelastic x-ray scattering (NRIXS) at sector 3-ID-B of the Advanced Photon Source [2, 3, 4]. The unit cell volume of each sample was determined at each compression point with in-situ x-ray diffraction at sector 3-ID-B before and after each NRIXS measurement. The Debye, compressional, and shear sound velocities were determined from the low energy region of the partial phonon density of states paired with the volume measurements. We will present partial phonon density of states and sound velocities for Fe0.9Ni0.1 and Fe0.85Ni0.1Si0.05 at high-pressure and compare with those of pure iron. References: [1] McDonough, W.F. (2004): Compositional Model for the Earth's Core. Elsevier Ltd., Oxford. [2] Murphy, C.A., J.M. Jackson, W. Sturhahn, and B. Chen (2011): Melting and thermal pressure of hcp-Fe from the phonon density of states, Phys. Earth Planet. Int., doi:10.1016/j.pepi.2011.07.001. [3] Murphy, C.A., J.M. Jackson, W. Sturhahn, and B. Chen (2011): Grüneisen parameter of hcp-Fe to 171 GPa, Geophys. Res. Lett., doi:10.1029/2011GL049531. [4] Murphy, C.A., J.M. Jackson, and W. Sturhahn (2013): Experimental constraints on the

  20. Comparing otoacoustic emissions evoked by chirp transients with constant absorbed sound power and constant incident pressure magnitude.

    PubMed

    Keefe, Douglas H; Feeney, M Patrick; Hunter, Lisa L; Fitzpatrick, Denis F

    2017-01-01

    Human ear-canal properties of transient acoustic stimuli are contrasted that utilize measured ear-canal pressures in conjunction with measured acoustic pressure reflectance and admittance. These data are referenced to the tip of a probe snugly inserted into the ear canal. Promising procedures to calibrate across frequency include stimuli with controlled levels of incident pressure magnitude, absorbed sound power, and forward pressure magnitude. An equivalent pressure at the eardrum is calculated from these measured data using a transmission-line model of ear-canal acoustics parameterized by acoustically estimated ear-canal area at the probe tip and length between the probe tip and eardrum. Chirp stimuli with constant incident pressure magnitude and constant absorbed sound power across frequency were generated to elicit transient-evoked otoacoustic emissions (TEOAEs), which were measured in normal-hearing adult ears from 0.7 to 8 kHz. TEOAE stimuli had similar peak-to-peak equivalent sound pressure levels across calibration conditions. Frequency-domain TEOAEs were compared using signal level, signal-to-noise ratio (SNR), coherence synchrony modulus (CSM), group delay, and group spread. Time-domain TEOAEs were compared using SNR, CSM, instantaneous frequency and instantaneous bandwidth. Stimuli with constant incident pressure magnitude or constant absorbed sound power across frequency produce generally similar TEOAEs up to 8 kHz.

  1. Study on mechanics of bodies under the action of sound pollution in industrial halls. Part II: Analysis of sound pressure inside the hall

    NASA Astrophysics Data System (ADS)

    Arghir, M.; Lăpuşan, I. L.

    2016-08-01

    In this work, it is taking into account all these phenomena of sounds propagation in given space. Within the framework of the given research is a study in industrial park "Teraplast" from Bistriţa-Năsăud county. This is industrial products for pvc constructions. From the submissions made to the workshops of processing industrial park "Teraplast" has been found, that noise is produced mainly in the power pumps hall. The registrations were made during a normal working days. The recorders made, for one minute, with recorder (NL32, Japanese society RION) in the pump's hall 12 positions were introduced in a high- capacity computer. This second part of the paper contains a natural continuation of the study conducted in the first part. Through the composition of sound waves for each pump in part according to the construction of the hall, gives the sound field generated by sources of power pumps during simultaneous operation. Field of noise sources inside the hall of power pumps determines an acoustic pressure on the walls of the hall. Taking into consideration the frequencies that are threatening the construction of the hall, will be presented successively acoustic pressure what special expertise to the hall walls the pressures of 230Hz, 350Hz, 800Hz and 1400Hz. This study is important for the acoustic pressure made from the "Teraplast" enterprise inside, and outside the halls.

  2. Towards a consensus on the pressure and composition dependence of sound velocity in the liquid Fe-S system

    NASA Astrophysics Data System (ADS)

    Nishida, Keisuke; Suzuki, Akio; Terasaki, Hidenori; Shibazaki, Yuki; Higo, Yuji; Kuwabara, Souma; Shimoyama, Yuta; Sakurai, Moe; Ushioda, Masashi; Takahashi, Eiichi; Kikegawa, Takumi; Wakabayashi, Daisuke; Funamori, Nobumasa

    2016-08-01

    Recent advances in techniques for high-pressure and high-temperature experiments enable us to measure the velocity of sound in liquid Fe alloys. However, reported velocities in liquid Fe-S differ among research groups (e.g., by >10% at 5 GPa), even when similar methods are used (i.e., the ultrasonic pulse-echo overlap method combined with a large volume press). To identify the causes of the discrepancies, we reanalyzed previous data and conducted additional sound velocity measurements for liquid Fe-S at 2-7 GPa, and evaluated the potential error sources. We found that the discrepancy cannot be explained by errors in the sound velocity measurements themselves, but by inaccuracies in determining the temperature, pressure, and chemical composition in each experiment. Of particular note are the significant errors introduced when determining pressures from the unit-cell volume of MgO, which is a temperature-sensitive pressure standard, using inaccurate temperatures. To solve the problem, we additionally used h-BN as a pressure standard, which is less sensitive to temperature. The pressure dependence of the sound velocity became smaller than that of the original data because of the revised pressure values. Our best estimate for the seismic velocity of the Moon's liquid outer core is 4.0 ± 0.1 km/s, given a chemical composition Fe83S17.

  3. Auditory mechanics in a bush-cricket: direct evidence of dual sound inputs in the pressure difference receiver

    PubMed Central

    Montealegre-Z, Fernando; Soulsbury, Carl D.; Robson Brown, Kate A.; Robert, Daniel

    2016-01-01

    The ear of the bush-cricket, Copiphora gorgonensis, consists of a system of paired eardrums (tympana) on each foreleg. In these insects, the ear is backed by an air-filled tube, the acoustic trachea (AT), which transfers sound from the prothoracic acoustic spiracle to the internal side of the eardrums. Both surfaces of the eardrums of this auditory system are exposed to sound, making it a directionally sensitive pressure difference receiver. A key feature of the AT is its capacity to reduce the velocity of sound propagation and alter the acoustic driving forces at the tympanum. The mechanism responsible for reduction in sound velocity in the AT remains elusive, yet it is deemed to depend on adiabatic or isothermal conditions. To investigate the biophysics of such multiple input ears, we used micro-scanning laser Doppler vibrometry and micro-computed X-ray tomography. We measured the velocity of sound propagation in the AT, the transmission gains across auditory frequencies and the time-resolved mechanical dynamics of the tympanal membranes in C. gorgonensis. Tracheal sound transmission generates a gain of approximately 15 dB SPL, and a propagation velocity of ca 255 m s−1, an approximately 25% reduction from free field propagation. Modelling tracheal acoustic behaviour that accounts for thermal and viscous effects, we conclude that reduction in sound velocity within the AT can be explained, among others, by heat exchange between the sound wave and the tracheal walls. PMID:27683000

  4. Auditory mechanics in a bush-cricket: direct evidence of dual sound inputs in the pressure difference receiver.

    PubMed

    Jonsson, Thorin; Montealegre-Z, Fernando; Soulsbury, Carl D; Robson Brown, Kate A; Robert, Daniel

    2016-09-01

    The ear of the bush-cricket, Copiphora gorgonensis, consists of a system of paired eardrums (tympana) on each foreleg. In these insects, the ear is backed by an air-filled tube, the acoustic trachea (AT), which transfers sound from the prothoracic acoustic spiracle to the internal side of the eardrums. Both surfaces of the eardrums of this auditory system are exposed to sound, making it a directionally sensitive pressure difference receiver. A key feature of the AT is its capacity to reduce the velocity of sound propagation and alter the acoustic driving forces at the tympanum. The mechanism responsible for reduction in sound velocity in the AT remains elusive, yet it is deemed to depend on adiabatic or isothermal conditions. To investigate the biophysics of such multiple input ears, we used micro-scanning laser Doppler vibrometry and micro-computed X-ray tomography. We measured the velocity of sound propagation in the AT, the transmission gains across auditory frequencies and the time-resolved mechanical dynamics of the tympanal membranes in C. gorgonensis Tracheal sound transmission generates a gain of approximately 15 dB SPL, and a propagation velocity of ca 255 m s(-1), an approximately 25% reduction from free field propagation. Modelling tracheal acoustic behaviour that accounts for thermal and viscous effects, we conclude that reduction in sound velocity within the AT can be explained, among others, by heat exchange between the sound wave and the tracheal walls.

  5. A modal test method using sound pressure transducers based on vibro-acoustic reciprocity

    NASA Astrophysics Data System (ADS)

    Zhu, W. D.; Liu, J. M.; Xu, Y. F.; Ying, H. Q.

    2014-06-01

    A modal test method that uses sound pressure transducers at fixed locations and an impact hammer roving over a test structure is developed in this work. Since sound pressure transducers are used, the current method deals with a coupled structural-acoustic system. Based on the vibro-acoustic reciprocity, the method is equivalent to one, where acoustic excitations at fixed locations are given and the resulting acceleration of the test structure is measured. The current method can eliminate mass loading due to use of accelerometers, which can destroy existence of repeated or close natural frequencies of a symmetric structure. It can also avoid effects of a nodal line of a mode and an inactive area of a local mode, and measure all the out-of-plane modes within a frequency range of interest, including global and local ones. The coupling between the structure and the acoustic field in a structural-acoustic system introduces asymmetry in the model formulation. An equivalent state space formulation is used for a damped structural-acoustic system and the associated eigenvalue problem is derived. The biorthonormality relations between the left and right eigenvectors and the relations between the structural and acoustic components in the left and right eigenvectors are proved. The frequency response functions associated with the current method are derived and their physical meanings are explained. The guidelines for using the current method, including the types of structures that are suitable for the method, the positions of the sound pressure transducers, and the orientation of the test structure relative to the transducers, are provided. Modal tests were carried out on an automotive disk brake using the traditional and current methods, where multiple accelerometers and microphones were used to measure its dynamic responses induced by impacts, respectively. The differences between the measured natural frequencies using the current method and those from the finite element

  6. Repeatability and accuracy testing of a weight distribution platform and comparison to a pressure sensitive walkway to assess static weight distribution.

    PubMed

    Bosscher, Georgia; Tomas, Andrea; Roe, Simon C; Marcellin-Little, Denis J; Lascelles, B Duncan X

    2017-03-20

    To evaluate the accuracy and repeatability of measurements collected using a weight distribution platform and a pressure sensitive walkway using an inanimate object with known weight distribution. A custom-built jig with a range of weights was applied in a random order. Measurements were collected on both devices and compared to each other and to the known weight distribution. Weight distribution platform and pressure sensitive walkway measurements were highly correlated to each other (Pearson's correlation coefficient R = 0.98) and to actual weights (R = 0.99 for the weight distribution platform; 0.98 for the pressure sensitive walkway). Repeatability from day to day for both devices was greater than 0.99. For the weight distribution platform, the 95% confidence interval was ± 2.5% from the true percentage and ± 3.3% for the pressure sensitive walkway. The coefficient of variation (COV) was highest for both devices at the lightest weights (weight distribution platform 11.28%, pressure sensitive walkway 16.91%) and lowest with the heaviest weights (weight distribution platform 3.71%, pressure sensitive walkway 5.86%). Both the weight distribution platform and the pressure sensitive walkway provided accurate and consistent measures of weight distribution with no significant difference between devices. The rounded standard error was three percent for the weight distribution platform, and four percent for the pressure sensitive walkway. The higher variability when measuring the smallest weight suggests less accuracy at lower weights with both devices. The weight distribution platform is a repeatable and accessible device to measure static weight distribution, and if proven the same in a clinical setting, it will be a valuable addition to current objective measures of limb use.

  7. Functional magnetic resonance imaging of sound pressure level encoding in the rat central auditory system.

    PubMed

    Zhang, Jevin W; Lau, Condon; Cheng, Joe S; Xing, Kyle K; Zhou, Iris Y; Cheung, Matthew M; Wu, Ed X

    2013-01-15

    Intensity is an important physical property of a sound wave and is customarily reported as sound pressure level (SPL). Invasive techniques such as electrical recordings, which typically examine one brain region at a time, have been used to study neuronal encoding of SPL throughout the central auditory system. Non-invasive functional magnetic resonance imaging (fMRI) with large field of view can simultaneously examine multiple auditory structures. We applied fMRI to measure the hemodynamic responses in the rat brain during sound stimulation at seven SPLs over a 72 dB range. This study used a sparse temporal sampling paradigm to reduce the adverse effects of scanner noise. Hemodynamic responses were measured from the central nucleus of the inferior colliculus (CIC), external cortex of the inferior colliculus (ECIC), lateral lemniscus (LL), medial geniculate body (MGB), and auditory cortex (AC). BOLD signal changes generally increase significantly (p<0.001) with SPL and the dependence is monotonic in CIC, ECIC, and LL. The ECIC has higher BOLD signal change than CIC and LL at high SPLs. The difference between BOLD signal changes at high and low SPLs is less in the MGB and AC. This suggests that the SPL dependences of the LL and IC are different from those in the MGB and AC and the SPL dependence of the CIC is different from that of the ECIC. These observations are likely related to earlier observations that neurons with firing rates that increase monotonically with SPL are dominant in the CIC, ECIC, and LL while non-monotonic neurons are dominant in the MGB and AC. Further, the IC's SPL dependence measured in this study is very similar to that measured in our earlier study using the continuous imaging method. Therefore, sparse temporal sampling may not be a prerequisite in auditory fMRI studies of the IC.

  8. Measurement of sound pressure and temperature in tissue-mimicking material using an optical fiber Bragg grating sensor.

    PubMed

    Imade, Keisuke; Kageyama, Takashi; Koyama, Daisuke; Watanabe, Yoshiaki; Nakamura, Kentaro; Akiyama, Iwaki

    2016-10-01

    The experimental investigation of an optical fiber Bragg grating (FBG) sensor for biomedical application is described. The FBG sensor can be used to measure sound pressure and temperature rise simultaneously in biological tissues exposed to ultrasound. The theoretical maximum values that can be measured with the FBG sensor are 73.0 MPa and 30 °C. In this study, measurement of sound pressure up to 5 MPa was performed at an ultrasound frequency of 2 MHz. A maximum temperature change of 6 °C was measured in a tissue-mimicking material. Values yielded by the FBG sensor agreed with those measured using a thermocouple and a hydrophone. Since this sensor is used to monitor the sound pressure and temperature simultaneously, it can also be used for industrial applications, such as ultrasonic cleaning of semiconductors under controlled temperatures.

  9. So Small, So Loud: Extremely High Sound Pressure Level from a Pygmy Aquatic Insect (Corixidae, Micronectinae)

    PubMed Central

    Sueur, Jérôme; Mackie, David; Windmill, James F. C.

    2011-01-01

    To communicate at long range, animals have to produce intense but intelligible signals. This task might be difficult to achieve due to mechanical constraints, in particular relating to body size. Whilst the acoustic behaviour of large marine and terrestrial animals has been thoroughly studied, very little is known about the sound produced by small arthropods living in freshwater habitats. Here we analyse for the first time the calling song produced by the male of a small insect, the water boatman Micronecta scholtzi. The song is made of three distinct parts differing in their temporal and amplitude parameters, but not in their frequency content. Sound is produced at 78.9 (63.6–82.2) SPL rms re 2.10−5 Pa with a peak at 99.2 (85.7–104.6) SPL re 2.10−5 Pa estimated at a distance of one metre. This energy output is significant considering the small size of the insect. When scaled to body length and compared to 227 other acoustic species, the acoustic energy produced by M. scholtzi appears as an extreme value, outperforming marine and terrestrial mammal vocalisations. Such an extreme display may be interpreted as an exaggerated secondary sexual trait resulting from a runaway sexual selection without predation pressure. PMID:21698252

  10. Postnatal development of sound pressure transformations by the head and pinnae of the cat: Monaural characteristics

    PubMed Central

    Tollin, Daniel J.; Koka, Kanthaiah

    2009-01-01

    Although there have been many anatomical, physiological, and psychophysical studies of auditory development in cat, there have been no comparable studies of the development of the sound pressured transformations by the cat head and pinnae. Because the physical dimensions of the head and pinnae determine the spectral and temporal transformations of sound, as head and pinnae size increase during development, the magnitude and frequency ranges of these transformations are hypothesized to systematically change. This hypothesis was tested by measuring directional transfer functions (DTFs), the directional components of head-related transfer functions, and the linear dimensions of the head and pinnae in cats from the onset of hearing (∼1.5 weeks) through adulthood. Head and pinnae dimensions increased by factors of ∼2 and ∼2.5, respectively, reaching adult values by ∼23 and ∼16 weeks, respectively. The development of the spectral notch cues to source location, the spatial- and frequency-dependent distributions of DTF amplitude gain (acoustic directionality), maximum gain, and the acoustic axis, and the resonance frequency and associated gain of the ear canal and concha were systematically related to the dimensions of the head and pinnae. These monaural acoustical properties of the head and pinnae in the cat are mature by 16 weeks. PMID:19206874

  11. Postnatal development of sound pressure transformations by the head and pinnae of the cat: monaural characteristics.

    PubMed

    Tollin, Daniel J; Koka, Kanthaiah

    2009-02-01

    Although there have been many anatomical, physiological, and psychophysical studies of auditory development in cat, there have been no comparable studies of the development of the sound pressured transformations by the cat head and pinnae. Because the physical dimensions of the head and pinnae determine the spectral and temporal transformations of sound, as head and pinnae size increase during development, the magnitude and frequency ranges of these transformations are hypothesized to systematically change. This hypothesis was tested by measuring directional transfer functions (DTFs), the directional components of head-related transfer functions, and the linear dimensions of the head and pinnae in cats from the onset of hearing ( approximately 1.5 weeks) through adulthood. Head and pinnae dimensions increased by factors of approximately 2 and approximately 2.5, respectively, reaching adult values by approximately 23 and approximately 16 weeks, respectively. The development of the spectral notch cues to source location, the spatial- and frequency-dependent distributions of DTF amplitude gain (acoustic directionality), maximum gain, and the acoustic axis, and the resonance frequency and associated gain of the ear canal and concha were systematically related to the dimensions of the head and pinnae. These monaural acoustical properties of the head and pinnae in the cat are mature by 16 weeks.

  12. Sound velocity of liquid Fe-Ni-S at high pressure

    NASA Astrophysics Data System (ADS)

    Kawaguchi, Saori I.; Nakajima, Yoichi; Hirose, Kei; Komabayashi, Tetsuya; Ozawa, Haruka; Tateno, Shigehiko; Kuwayama, Yasuhiro; Tsutsui, Satoshi; Baron, Alfred Q. R.

    2017-05-01

    The sound velocity of liquid Fe47Ni28S25 and Fe63Ni12S25 was measured up to 52 GPa/2480 K in externally resistance-heated and laser-heated diamond-anvil cells using high-resolution inelastic X-ray scattering. From these experimental data, we obtained the elastic parameters of liquid Fe47Ni28S25, KS0 = 96.1 ± 2.7 GPa and KS0' = 4.00 ± 0.13, where KS0 and KS0' are the adiabatic bulk modulus and its pressure derivative at 1 bar, when the density is fixed at ρ0 = 5.62 ± 0.09 g/cm3 for 1 bar and 2000 K. With these parameters, the sound velocity and density of liquid Fe47Ni28S25 were calculated to be 8.41 ± 0.17 km/s and 8.93 ± 0.19 to 9.10 ± 0.18 g/cm3, respectively, at the core mantle boundary conditions of 135 GPa and 3600-4300 K. These values are 9.4% higher and 17-18% lower than those of pure Fe, respectively. Extrapolation of measurements and comparison with seismological models suggest the presence of 5.8-7.5 wt % sulfur in the Earth's outer core if it is the only light element.

  13. Sound Transmission through Cylindrical Shell Structures Excited by Boundary Layer Pressure Fluctuations

    NASA Technical Reports Server (NTRS)

    Tang, Yvette Y.; Silcox, Richard J.; Robinson, Jay H.

    1996-01-01

    This paper examines sound transmission into two concentric cylindrical sandwich shells subject to turbulent flow on the exterior surface of the outer shell. The interior of the shells is filled with fluid medium and there is an airgap between the shells in the annular space. The description of the pressure field is based on the cross-spectral density formulation of Corcos, Maestrello, and Efimtsov models of the turbulent boundary layer. The classical thin shell theory and the first-order shear deformation theory are applied for the inner and outer shells, respectively. Modal expansion and the Galerkin approach are used to obtain closed-form solutions for the shell displacements and the radiation and transmission pressures in the cavities including both the annular space and the interior. The average spectral density of the structural responses and the transmitted interior pressures are expressed explicitly in terms of the summation of the cross-spectral density of generalized force induced by the boundary layer turbulence. The effects of acoustic and hydrodynamic coincidences on the spectral density are observed. Numerical examples are presented to illustrate the method for both subsonic and supersonic flows.

  14. A theoretical study of the effect of forward speed on the free-space sound-pressure field around propellers

    NASA Technical Reports Server (NTRS)

    Garrick, I E; Watkins, Charles E

    1954-01-01

    The sound-pressure field of a rotating propeller in forward flight in free space is analyzed by replacing the normal-pressure distribution over the propeller associated with thrust and torque by a distribution of acoustic pressure doublets acting at the propeller disk and subject to uniform rectilinear motion. The basic element used to synthesize the field is the pressure field of a concentrated force moving uniformly at subsonic speeds, for which an expression generalizing one of Lamb's for the fixed concentrated force is given. The sound field is expressed by integration over the propeller disk, and also by integration over an effective ring, and is given both for the near pressure field and, in a simpler form, for the far field. Some illustrated examples are calculated and discussed.

  15. Pressure-driven sound turbulence in a high-beta plasma

    NASA Technical Reports Server (NTRS)

    Stenzel, R. L.

    1990-01-01

    LF turbulence is investigated experimentally in a 2-m-long 1-m-diameter magnetized electron fluid with beta(e) = about 0.5 and unmagnetized ions, generated in a double-pulsed linear dc discharge under a uniform external magnetic field of 15 G. The results of measurements with Langmuir probes, electric probes, and a directional particle analyzer are presented in graphs and characterized in detail. It is shown that the strong cross-field sound turbulence observed near the lower hybrid frequency is caused by the electron pressure gradient rather than E x B drift, with (1) temperature-gradient wave refraction as the dominant saturation mechanism, (2) wave-enhanced ion mass flow, and (3) only negligible ion-tail formation. The relevance of the present findings for studies of magnetic shock propagation is indicated.

  16. Effect of water vapor on sound absorption in nitrogen at low frequency/pressure ratios

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.; Griffin, W. A.

    1981-01-01

    Sound absorption measurements were made in N2-H2O binary mixtures at 297 K over the frequency/pressure range f/P of 0.1-2500 Hz/atm to investigate the vibrational relaxation peak of N2 and its location on f/P axis as a function of humidity. At low humidities the best fit to a linear relationship between the f/P(max) and humidity yields an intercept of 0.013 Hz/atm and a slope of 20,000 Hz/atm-mole fraction. The reaction rate constants derived from this model are lower than those obtained from the extrapolation of previous high-temperature data.

  17. Effect of water vapor on sound absorption in nitrogen at low frequency/pressure ratios

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.; Griffin, W. A.

    1981-01-01

    Sound absorption measurements were made in N2-H2O binary mixtures at 297 K over the frequency/pressure range f/P of 0.1-2500 Hz/atm to investigate the vibrational relaxation peak of N2 and its location on f/P axis as a function of humidity. At low humidities the best fit to a linear relationship between the f/P(max) and humidity yields an intercept of 0.013 Hz/atm and a slope of 20,000 Hz/atm-mole fraction. The reaction rate constants derived from this model are lower than those obtained from the extrapolation of previous high-temperature data.

  18. Locked-in syndrome caused by the pressure exerted by the sound gun.

    PubMed

    Ozer, Ayse Belin; Demirel, Ismail; Bayar, Mustafa K; Gunduz, Gulay; Tokdemir, Mehmet

    2014-11-01

    A 19-year-old male patient who wounded himself with a gun in the cranial region had a Glasgow coma scale of 3E. At posttraumatic day 7, locked-in syndrome was considered upon detection of vertical eye movements, meaningful winks, and quadriplegia. Apart from the classical view, computed tomography (CT) and postmortem examination of the brain showed an infarct area in the cerebellum. However, vertebrobasilar artery system was normal. In this case report, we would like to present that unlike cases with ischemia, specific CT findings may not be evident in posttraumatic cases and ischemia may occur in the cerebellum as a result of the pressure exerted by a sound gun.

  19. Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones.

    PubMed

    MacLean, G L; Stuart, A; Stenstrom, R

    1992-11-01

    Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

  20. Reference threshold sound-pressure levels for the TDH-50 and ER-3A earphones.

    PubMed

    Larson, V D; Cooper, W A; Talbott, R E; Schwartz, D M; Ahlstrom, C; De Chicchis, A R

    1988-07-01

    Reference threshold sound-pressure levels were established for a new insert earphone, the ER-3A tubephone, and for the TDH-50 earphone. In test-retest comparisons, the tubephone produced estimates of auditory threshold as reliable as the thresholds produced by the supraaural earphone. Reference thresholds were developed for the two earphones from data contributed by three laboratories. While the TDH-50 data are in good agreement with the provisional ANSI 6-cc coupler reference levels (ASHA, 1982), the ER-3A data are at variance with the manufacturer's provisional recommendation for 2-cc coupler reference thresholds for frequencies below 1 kHz. The differences are attributed to physiologic noise that masked the lower frequency thresholds.

  1. A model for the pressure excitation spectrum and acoustic impedance of sound absorbers in the presence of grazing flow

    NASA Technical Reports Server (NTRS)

    Rice, E. J.

    1973-01-01

    The acoustic impedance of sound absorbers in the presence of grazing flow is essential information when analyzing sound propagation within ducts. A unification of the theory of the nonlinear acoustic resistance of Helmholtz resonators including grazing flow is presented. The nonlinear resistance due to grazing flow is considered to be caused by an exciting pressure spectrum produced by the interaction of the grazing flow and the jets flowing from the resonator orifices. With this exciting pressure spectrum the resonator can be treated in the same manner as a resonator without grazing flow but with an exciting acoustic spectrum.

  2. Direct measurements of sound velocities of iron with nuclear resonant inelastic x-ray scattering under high pressure and temperature

    NASA Astrophysics Data System (ADS)

    Lin, J.; Sturhahn, W.; Zhao, J.; Shen, G.; Mao, H.; Hemley, R.

    2004-05-01

    Iron is the most abundant component in the Earth's core. Understanding the physical properties of Fe under core conditions is crucial for interpreting the seismological and geomagnetic observations deep in the Earth's interior. The physical properties of Fe have been extensively studied by dynamic and static high-pressure experiments and theoretical calculations, but direct static measurements of the sound velocities of iron under high pressures and temperatures are still lacking. We have built a double-sided YLF laser heating system to study iron with nuclear resonant inelastic x-ray scattering technique under simultaneously high pressures and high temperatures. Sound velocities of iron have been directly measured up to 58 GPa and 1700 K in a laser-heated diamond cell. The ''detailed balance'' principle applied to the inelastic X-ray scattering spectra provides absolute temperatures of the laser-heated sample. These temperatures are in very good agreement with values determined from the thermal radiation spectra fitted to the Planck radiation function. This independent temperature measurement of the laser-heated sample confirms the validity of temperatures determined from Planck radiation law in the laser-heated diamond anvil cell experiments. We found that temperature has a strong effect on the sound velocities; the compressional (VP) and shear wave velocities (VS) of hcp-Fe decrease significantly with increasing temperature under high pressures. VP and VS are only linearly related to the density for a given, constant temperature, while the bulk sound velocity (Vφ ) follows Birch's law, i.e., Vφ is linearly related to the density and mean atomic weight. The linear sound velocity-density line should be corrected to lower velocities in extrapolations to inner core conditions. Our results have important implications for understanding the sound velocities of the Earth's inner core as well as the fundamental physical properties of iron under extreme pressures and

  3. Respiratory modulation of oscillometric cuff pressure pulses and Korotkoff sounds during clinical blood pressure measurement in healthy adults.

    PubMed

    Chen, Diliang; Chen, Fei; Murray, Alan; Zheng, Dingchang

    2016-05-10

    Accurate blood pressure (BP) measurement depends on the reliability of oscillometric cuff pressure pulses (OscP) and Korotkoff sounds (KorS) for automated oscillometric and manual techniques. It has been widely accepted that respiration is one of the main factors affecting BP measurement. However, little is known about how respiration affects the signals from which BP measurement is obtained. The aim was to quantify the modulation effect of respiration on oscillometric pulses and KorS during clinical BP measurement. Systolic and diastolic BPs were measured manually from 40 healthy subjects (from 23 to 65 years old) under normal and regular deep breathing. The following signals were digitally recorded during linear cuff deflation: chest motion from a magnetometer to obtain reference respiration, cuff pressure from an electronic pressure sensor to derive OscP, and KorS from a digital stethoscope. The effects of respiration on both OscP and KorS were determined from changes in their amplitude associated with respiration between systole and diastole. These changes were normalized to the mean signal amplitude of OscP and KorS to derive the respiratory modulation depth. Reference respiration frequency, and the frequencies derived from the amplitude modulation of OscP and KorS were also calculated and compared. Respiratory modulation depth was 14 and 40 % for OscP and KorS respectively under normal breathing condition, with significant increases (both p < 0.05) to 16 and 49 % with deeper breathing. There was no statistically significant difference between the reference respiration frequency and those derived from the oscillometric and Korotkoff signals (both p > 0.05) during deep breathing, and for the oscillometric signal during normal breathing (p > 0.05). Our study confirmed and quantified the respiratory modulation effect on the oscillometric pulses and KorS during clinical BP measurement, with increased modulation depth under regular deeper breathing.

  4. Peak Sound Pressure Levels and Associated Auditory Risk from an H[subscript 2]-Air "Egg-Splosion"

    ERIC Educational Resources Information Center

    Dolhun, John J.

    2016-01-01

    The noise level from exploding chemical demonstrations and the effect they could have on audiences, especially young children, needs attention. Auditory risk from H[subscript 2]- O2 balloon explosions have been studied, but no studies have been done on H[subscript 2]-air "eggsplosions." The peak sound pressure level (SPL) was measured…

  5. Peak Sound Pressure Levels and Associated Auditory Risk from an H[subscript 2]-Air "Egg-Splosion"

    ERIC Educational Resources Information Center

    Dolhun, John J.

    2016-01-01

    The noise level from exploding chemical demonstrations and the effect they could have on audiences, especially young children, needs attention. Auditory risk from H[subscript 2]- O2 balloon explosions have been studied, but no studies have been done on H[subscript 2]-air "eggsplosions." The peak sound pressure level (SPL) was measured…

  6. The Influence of Fundamental Frequency and Sound Pressure Level Range on Breathing Patterns in Female Classical Singing

    ERIC Educational Resources Information Center

    Collyer, Sally; Thorpe, C. William; Callaghan, Jean; Davis, Pamela J.

    2008-01-01

    Purpose: This study investigated the influence of fundamental frequency (F0) and sound pressure level (SPL) range on respiratory behavior in classical singing. Method: Five trained female singers performed an 8-s messa di voce (a crescendo and decrescendo on one F0) across their musical F0 range. Lung volume (LV) change was estimated, and…

  7. The Influence of Fundamental Frequency and Sound Pressure Level Range on Breathing Patterns in Female Classical Singing

    ERIC Educational Resources Information Center

    Collyer, Sally; Thorpe, C. William; Callaghan, Jean; Davis, Pamela J.

    2008-01-01

    Purpose: This study investigated the influence of fundamental frequency (F0) and sound pressure level (SPL) range on respiratory behavior in classical singing. Method: Five trained female singers performed an 8-s messa di voce (a crescendo and decrescendo on one F0) across their musical F0 range. Lung volume (LV) change was estimated, and…

  8. How does the sound pressure generated by circumaural, supra-aural, and insert earphones differ for adult and infant ears?

    PubMed

    Voss, Susan E; Herrmann, Barbara S

    2005-12-01

    To determine how the ear canal sound pressure levels generated by circumaural, supra-aural, and insert earphones differ when coupled to the normal adult and infant ear. The ratio between the sound pressure generated in an adult ear and an infant ear was calculated for three types of earphones: a circumaural earphone (Natus Medical, ALGO with Flexicoupler), a supra-aural earphone (Telephonics, TDH-49 with MXAR cushion), and an insert earphone placed in the ear canal (Etymoup and down arrow tic Research, ER-3A). The calculations are based on (1) previously published measurements of ear canal impedances in adult and infant (ages 1, 3, 6, 12, and 24 months) ears (Keefe et al., 1993, Acoustic Society of America, 94:2617-2638), (2) measurements of the Thévenin equivalent for each earphone configuration, and (3) acoustic models of the ear canal and external ear. Sound-pressure levels depend on the ear canal location at which they are measured. For pressures at the earphone: (1) Circumaural and supra-aural earphones produce changes between infant and adult ears that are less than 3 dB at all frequencies, and (2) insert earphones produce infant pressures that are up to 15 dB greater than adult pressures. For pressures at the tympanic membrane: (1) Circumaural and supra-aural earphones produce infant pressures that are within 2 dB of adult ears at frequencies below 2000 Hz and that are 5 to 7 dB smaller in infant ears than adult ears above 2000 Hz, and (2) insert earphones produce pressures that are 5 to 8 dB larger in infant ears than adult ears across all audiometric frequencies. Sound pressures generated by all earphone types (circumaural, supra-aural, and insert) depend on the dimensions of the ear canal and on the impedance of the ear at the tympanic membrane (e.g., infant versus adult). Specific conclusions depend on the location along the ear canal at which the changes between adult and infant ears are referenced (i.e., the earphone output location or the tympanic

  9. Application of the Extreme Value Distribution to Estimate the Uncertainty of Peak Sound Pressure Levels at the Workplace.

    PubMed

    Lenzuni, Paolo

    2015-07-01

    The purpose of this article is to develop a method for the statistical inference of the maximum peak sound pressure level and of the associated uncertainty. Both quantities are requested by the EU directive 2003/10/EC for a complete and solid assessment of the noise exposure at the workplace. Based on the characteristics of the sound pressure waveform, it is hypothesized that the distribution of the measured peak sound pressure levels follows the extreme value distribution. The maximum peak level is estimated as the largest member of a finite population following this probability distribution. The associated uncertainty is also discussed, taking into account not only the contribution due to the incomplete sampling but also the contribution due to the finite precision of the instrumentation. The largest of the set of measured peak levels underestimates the maximum peak sound pressure level. The underestimate can be as large as 4 dB if the number of measurements is limited to 3-4, which is common practice in occupational noise assessment. The extended uncertainty is also quite large (~2.5 dB), with a weak dependence on the sampling details. Following the procedure outlined in this article, a reliable comparison between the peak sound pressure levels measured in a workplace and the EU directive action limits is possible. Non-compliance can occur even when the largest of the set of measured peak levels is several dB below such limits. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  10. Positive Peer-Pressured Productivity (P-QUAD): Novel Use of Increased Transparency and a Weighted Lottery to Increase a Division's Academic Output.

    PubMed

    Pitt, Michael B; Furnival, Ronald A; Zhang, Lei; Weber-Main, Anne M; Raymond, Nancy C; Jacob, Abraham K

    2017-03-01

    Evaluate a dual incentive model combining positive peer pressure through increased transparency of peers' academic work with a weighted lottery where entries are earned based on degree of productivity. We developed a dual-incentive peer mentoring model, Positive Peer-Pressured Productivity (P-QUAD), for faculty in the Pediatric Hospital Medicine Division at the University of Minnesota Masonic Children's Hospital. This model provided relative value-based incentives, with points assigned to different scholarly activities (eg. 1 point for abstract submission, 2 points for poster presentation, 3 points for oral presentation, etc.). These points translated into to lottery tickets for a semi-annual drawing for monetary prizes. Productivity was compared among faculty for P-QUAD year to the preintervention year. Fifteen (83%) of 18 eligible faculty members participated. Overall annual productivity per faculty member as measured by total P-QUAD score increased from a median of 3 (interquartile range [IQR] 0-14) in the preintervention year to 4 (IQR 0-27) in the P-QUAD year (P = .051). Submissions and acceptances increased in all categories except posters which were unchanged. Annual abstract submissions per faculty member significantly increased from a median of 1 (IQR 0-2) to 2 (IQR 0-2; P = .047). Seventy-three percent (8 of 11) of post-survey respondents indicated that the financial incentive motivated them to submit academic work; 100% indicated that increased awareness of their peers' work was a motivator. The combination of increased awareness of peers' academic productivity and a weighted lottery financial incentive appears to be a useful model for stimulating academic productivity in early-career faculty. Copyright © 2016 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  11. Differential Sound Absorption Technique and Effect of Ion-Pairing and Pressure on Sound Absorption in Seawater and Aqueous Mixtures of Magnesium Sulfate and sodium Chloride.

    DTIC Science & Technology

    1981-11-01

    Ws Sound absorption, seawater, ion-pairing, pressure, ion-association models, MgSo4 solutions, MgS0 4 - MaC1 mixtures, Debye - Huckel theory . 20...solution upon the addition of NaCI can be accounted for theoretically by Debye - Huckel theory and by formation of MgCW and NaSO ion-pairs. The measured...M NaCl addition. For 0.6M NaCI addition to 0.02 M MgS04, the absorption results cannot be explained by either simple Debye - Huckel theory , the Johnson

  12. Investigation of the relationship between electroglottogram waveform, fundamental frequency, and sound pressure level using clustering.

    PubMed

    Selamtzis, Andreas; Ternström, Sten

    2016-12-08

    Although it has been shown in previous research (Orlikoff, 1991; Henrich et al, 2005; Kuang et al, 2014; Awan, 2015) that there exists a relationship between the electroglottogram (EGG) waveform and the acoustic signal, this relationship is still not fully understood. To investigate this relationship, the EGG and acoustic signals were measured for four male amateur choir singers who each produced eight consecutive tones of increasing and decreasing vocal intensity. The EGG signals were processed cycle-synchronously to obtain the discrete Fourier transform, and the data were used as an input to a clustering algorithm. The acoustic signal was analyzed in terms of sound pressure level (dB SPL) and fundamental frequency (fo) of vibration, and the results of both EGG and acoustic analysis were depicted on a two-dimensional plane with fo on the x-axis and SPL on the y-axis. All the subjects were seen to have a weak, near-sinusoidal EGG waveform in their lowest SPL range, whereas increase in SPL coincided with progressive enrichment in harmonic content of the EGG waveforms. The results of the clustering were additionally used to classify waveforms across subjects to enable inter-subject comparisons and assessment of individual strategies of exploring the fo-SPL dimensions. In these male subjects, the EGG waveform shape appeared to vary with SPL and to remain essentially constant with fo over one octave.

  13. Output sound pressure levels of personal music systems and their effect on hearing.

    PubMed

    Kumar, Ajith; Mathew, Kuruvilla; Alexander, Swathy Ann; Kiran, Chitra

    2009-01-01

    This study looked at output levels produced by new generation personal music systems (PMS), at the level of eardrum by placing the probe microphone in the ear canal. Further, the effect of these PMS on hearing was evaluated by comparing the distortion product otoacoustic emissions and high frequency pure tone thresholds (from 3 kHz to 12 kHz) of individuals who use PMS to that of age matched controls who did not use PMS. The relationship between output sound pressure levels and hearing measures was also evaluated. In Phase I output SPLs produced by the PMS were measured in three different conditions - a) at volume control setting that was preferred by the subjects in quiet b) at volume control setting that was preferred by the subject in presence of 65 dB SPL bus noise c) at maximum volume control settings of the instrument. In Phase II pure tone hearing thresholds and DPOAEs were measured. About 30% of individuals in a group of 70 young adults listened to music above the safety limits (80 dBA for 8 hours) prescribed by Ministry of Environment and Forests, India. Addition of bus noise did not increase the preferred volume control settings of the subjects significantly. There were no significant differences between the experimental and control groups for mean pure tone threshold and for mean DPOAE amplitude comparisons. However, a positive correlation between hearing thresholds and music levels and a negative correlation between DPOAE measures and music levels were found.

  14. Thermal conductivity and sound velocity of antigorite at high pressure using time-domain thermoreflectance

    NASA Astrophysics Data System (ADS)

    Chien, Y. H.; Hsieh, W. P.

    2016-12-01

    We measure the thermal conductivity and compressional wave velocity of antigorite at room temperature and up to 13 GPa. Antigorite is a serpentine mineral (Mg6Si4O10(OH)8) of high-temperature form having a wavy structure and it has a wide stability field (e.g., up to 720°C at 2 GPa or 620°C at 5 GPa), which is a key material for understanding slab subduction, deep earthquake and volcanic processes in the mantle wedge where fluids from the dehydrating oceanic crust interact with the mantle. The mineral phases, chemical compositions, and crystal orientations of the antigorite were analyzed using Raman spectroscopy, energy-dispersive spectroscopy, and electron backscattered diffraction, respectively. The measurements of thermal conductivities and sound velocities of antigorite with different crystal orientations were carried out by time-domain thermoreflectance (TDTR). At P<7 GPa, thermal conductivity becomes more anisotropic with increasing pressure but becomes more isotropic in elastic property between b and c-axis. We also discuss the lattice internal rearrangement may induce over three times increase in thermal conductivity at 7 GPa ( 210 km depth) which would enhance larger heat flux along b-axis in the serpentinized slab. Thus, it gives new insights into the potential influence of thermal conductivity anisotropy on the mineral dehydration processes in the subduction zone.

  15. Multichannel loudness compensation method based on segmented sound pressure level for digital hearing aids

    NASA Astrophysics Data System (ADS)

    Liang, Ruiyu; Xi, Ji; Bao, Yongqiang

    2017-07-01

    To improve the performance of gain compensation based on three-segment sound pressure level (SPL) in hearing aids, an improved multichannel loudness compensation method based on eight-segment SPL was proposed. Firstly, the uniform cosine modulated filter bank was designed. Then, the adjacent channels which have low or gradual slopes were adaptively merged to obtain the corresponding non-uniform cosine modulated filter according to the audiogram of hearing impaired persons. Secondly, the input speech was decomposed into sub-band signals and the SPL of every sub-band signal was computed. Meanwhile, the audible SPL range from 0 dB SPL to 120 dB SPL was equally divided into eight segments. Based on these segments, a different prescription formula was designed to compute more detailed gain to compensate according to the audiogram and the computed SPL. Finally, the enhanced signal was synthesized. Objective experiments showed the decomposed signals after cosine modulated filter bank have little distortion. Objective experiments showed that the hearing aids speech perception index (HASPI) and hearing aids speech quality index (HASQI) increased 0.083 and 0.082 on average, respectively. Subjective experiments showed the proposed algorithm can effectively improve the speech recognition of six hearing impaired persons.

  16. Sound power and pressure level measurements in the inlet and outlet of an HRSG duct

    NASA Astrophysics Data System (ADS)

    Jungbauer, D. E.; Unruh, J. F.; Rose, S.; Pantermuehl, P. J.

    1995-04-01

    The ever-increasing size of cogeneration facilities has mandated the need for noise abatement in the design stage. Many noise projection models are available to the industry for predicting noise levels in and adjacent to new installations. However, the models all require accurate source noise information if valid noise predictions are to be expected. As a consequence of designing one of the world's largest cogeneration installations involving eight Model W-701 turbine units and their Heat Recovery Steam Generators (HRSGs), it became apparent that the attention between the exhaust of the turbine and the outlet of the HRSGs was not well known. Not having this information posed potentially expensive noise abatement modifications during the design and construction phases. In order to verify the adequacy of scaling studies from a W-501 turbine and HRSG to the W-701 system, a comprehensive field test of an existing W-501 installation was conducted. This paper describes the design of an acoustic intensity and sound pressure probe to operate inside the high-temperature ductwork, the access engineering required, data acquisition, and final results concerning noise attenuation across the HRSG.

  17. Characteristics of surface sound pressure and absorption of a finite impedance strip for a grazing incident plane wave.

    PubMed

    Sum, K S; Pan, J

    2007-07-01

    Distributions of sound pressure and intensity on the surface of a flat impedance strip flush-mounted on a rigid baffle are studied for a grazing incident plane wave. The distributions are obtained by superimposing the unperturbed wave (the specularly reflected wave as if the strip is rigid plus the incident wave) with the radiated wave from the surface vibration of the strip excited by the unperturbed pressure. The radiated pressure interferes with the unperturbed pressure and distorts the propagating plane wave. When the plane wave propagates in the baffle-strip-baffle direction, it encounters discontinuities in acoustical impedance at the baffle-strip and strip-baffle interfaces. The radiated pressure is highest around the baffle-strip interface, but decreases toward the strip-baffle interface where the plane wave distortion reduces accordingly. As the unperturbed and radiated waves have different magnitudes and superimpose out of phase, the surface pressure and intensity increase across the strip in the plane wave propagation direction. Therefore, the surface absorption of the strip is nonzero and nonuniform. This paper provides an understanding of the surface pressure and intensity behaviors of a finite impedance strip for a grazing incident plane wave, and of how the distributed intensity determines the sound absorption coefficient of the strip.

  18. Investigation of the Sound Pressure Level (SPL) of earphones during music listening with the use of physical ear canal models

    NASA Astrophysics Data System (ADS)

    Aying, K. P.; Otadoy, R. E.; Violanda, R.

    2015-06-01

    This study investigates on the sound pressure level (SPL) of insert-type earphones that are commonly used for music listening of the general populace. Measurements of SPL from earphones of different respondents were measured by plugging the earphone to a physical ear canal model. Durations of the earphone used for music listening were also gathered through short interviews. Results show that 21% of the respondents exceed the standard loudness/duration relation recommended by the World Health Organization (WHO).

  19. Phase relations and sound velocity measurements of iron-sulfur systems at high pressure: implications for the Earth's inner core

    NASA Astrophysics Data System (ADS)

    Ohtani, E.; Kamada, S.; Sakai, T.; Terasaki, H.; Shibazaki, Y.; Sakamaki, T.; Takahashi, S.; Sakairi, T.; Fukui, H.; Baron, A. Q.

    2012-12-01

    The sound velocity is one of the most important physical properties which can be assessed by seismology. In spite of its importance, the technical difficulty provides limitation of the measurements under the core conditions. Here we show the results of measurements of the sound velocity of hcp-iron, Fe3S, and FeH by the inelastic X-ray scattering (IXS) method using DAC at high pressure and temperature. Inelastic X-ray scattering spectra were taken at BL35XU, Spring-8. We made the measurements of hcp-iron at pressures up to 180 GPa at room temperature, which is the highest pressure for the IXS measurement. Sound velocity measurements at high pressure and temperature were made up to 91 GPa at 700 K, and to 62 GPa and 1000 K using the external heating diamond anvil cell. The present results revealed that there is almost no temperature effect on the sound velocity of hcp-Fe at least up to 1000 K. We also measured the sound velocity and density of Fe3S up to 85 GPa at room temperature, and clarified the effect of sulfur and hydrogen on the sound velocity of iron at high pressure. Phase relations of the Fe-S (Kamada et al., 2010; 2012) and Fe-S-O systems (Terasaki et al., 2011) were studied up to the core pressures based on the laser heated diamond anvil cell combined with the in situ synchrotron X-ray diffraction at SPring-8. Fe3S dissolves first at the solidus before melting of FeO and metallic iron alloy at the liquidus of the systems up to 180 GPa. The maximum solubility of sulfur in hcp-iron approaches to about 7.5 at % at 86 GPa and 8 at % at 123 GPa, and it does not increase so much at higher pressures. The temperature at ICB based on the extrapolation of the liquidus and solidus temperatures of the outer core composition in the Fe-S-O is about 4360-5630 K assuming that the outer core composition is Fe75O5S20 in the atomic ratio. The temperature at the core-mantle boundary will be 3340-4300 K by the adiabatic decompression from the temperature at the inner core

  20. Exposure to classroom sound pressure level among dance teachers in Porto Alegre (RS)

    PubMed Central

    Nehring, Cristiane; Bauer, Magda Aline; Teixeira, Adriane Ribeiro

    2013-01-01

    Summary Introduction: Dance teachers are exposed to high sound intensities. Aim: To verify the sound intensity of music used by dance teachers during classes. Method: This was a transversal and prospective study. Dance teachers were evaluated with a sociodemographic questionnaire, and sound intensity level measurements were taken at the beginning, middle, and end of dance classes. Results: The sample comprised 35 teachers (average age, 31.8 years). The duration of their career as dance teachers was 1–37 years; they worked daily for approximately 1–10 h. Among the classes followed, there were 15 (42.85%) classical ballet classes, 4 (11.42%) tap dancing lessons, 5 (14.28%) jazz dance classes, 2 (5.71) Arab dance lessons, 6 (17.14%) street dance classes, and 3 (8.57%) ballroom dancing lessons. The average values observed at the beginning, middle, and end of the classes were 80.91 dB (A), 83.22 dB (A), and 85.19 dB (A), respectively. The music played in the street dance classes exposed teachers to the highest sound intensity. Conclusion: The average level of sound intensity of the dance classes in this study was either below or equal to the limit considered harmful for hearing health. Analysis of different class types showed that the sound densities of street, ballroom, and tap dance classes were above the recommended limits. PMID:25991989

  1. Density and Sound Velocity of Iron-Sulfur Alloying Liquids at High Pressures and Implications to Planetary Cores

    SciTech Connect

    Jing, Z.; Wang, Y.; Yu, T.; Sakamaki, T.; Kono, Y.; Park, C.

    2012-04-30

    Liquid Fe-light element alloys are likely present in the Earth's outer core and the cores (or outer cores) of other terrestrial planets such as Moon, Mercury, and Mars, suggested by geophysical and geochemical observations. In order to determine the abundances of light elements and their effects on the structure, dynamics, and evolution of planetary cores, it is crucial to determine the equation of state for Fe-light element alloying liquids under core conditions. However, density data on liquid Fe-light element alloys at core pressures are very limited and no sound velocity or bulk modulus data are available for these liquids at high pressures. This makes it difficult to extrapolate the equation of state to core pressures. As a result, density data on solid Fe alloys are often used in the literature to compare with seismological observations by making rough corrections for the volume of melting. In this study, we determine the density and sound velocity for Fe-S liquids with different sulfur contents at high pressure and temperature conditions up to 8 GPa and 2173 K using synchrotron X-ray techniques.

  2. The clarinet: how blowing pressure, lip force, lip position and reed "hardness" affect pitch, sound level, and spectrum.

    PubMed

    Almeida, Andre; George, David; Smith, John; Wolfe, Joe

    2013-09-01

    Using an automated clarinet playing system, the frequency f, sound level L, and spectral characteristics are measured as functions of blowing pressure P and the force F applied by the mechanical lip at different places on the reed. The playing regime on the (P,F) plane lies below an extinction line F(P) with a negative slope of a few square centimeters and above a pressure threshold with a more negative slope. Lower values of F and P can produce squeaks. Over much of the playing regime, lines of equal frequency have negative slope. This is qualitatively consistent with passive reed behavior: Increasing F or P gradually closes the reed, reducing its equivalent acoustic compliance, which increases the frequency of the peaks of the parallel impedance of bore and reed. High P and low F produce the highest sound levels and stronger higher harmonics. At low P, sound level can be increased at constant frequency by increasing P while simultaneously decreasing F. At high P, where lines of equal f and of equal L are nearly parallel, this compensation is less effective. Applying F further from the mouthpiece tip moves the playing regime to higher F and P, as does a stiffer reed.

  3. Clinical validation of the accutracker, a novel ambulatory blood pressure monitor using R-wave gating for Korotkoff sounds.

    PubMed

    White, W B; Schulman, P; McCabe, E J; Nardone, M B

    1987-12-01

    We compared simultaneous, same-arm blood pressure (BPs) obtained with the Accutracker, an ambulatory blood pressure (BP) monitor, which uses R-wave gating for Korotkoff sounds to those of both a blinded, skilled clinician using a mercury column and a three-channel graphic display of cuff pressure tracings, Korotkoff sounds, and ECG tracing. Eighteen subjects, with a wide variety of BPs, heart rates, and ages, participated in the study. The systolic BP obtained by the ambulatory recorder, clinician, and the three-channel strip chart recorder were 132 +/- 23 mmHg, 132 +/- 24 mmHg, and 133 +/- 25 mmHg, (all NS), respectively. Accutracker recorder-determined systolic BP correlated highly both with the clinician and strip chart readings (r = 0.98 and 0.97, respectively; p less than 0.0001 for both). The diastolic BP obtained by the Accutracker recorder was slightly, but significantly, lower than the clinician's readings (76 +/- 12 mmHg vs. 81 +/- 13 mmHg; p less than 0.005) and similar to the strip chart recorder readings (76 +/- 12 mmHg vs. 77 +/- 12 mmHg; NS). In 32 young, healthy subjects with no activity restrictions, 91% of the raw BP data from 24-hour ambulatory recordings was acceptable using strict deletion criteria. These data demonstrate that the Accutracker is highly accurate compared with clinician-determined blood pressures. The lower diastolic BP readings may stem from the ability of this device to detect softer Korotkoff sounds than can be detected by the clinician. These findings should be taken into consideration when using ambulatory BP monitoring in clinical trials of antihypertensive drugs.

  4. Programmable auditory stimulus generator and electro-acoustic transducers--measurements of sound pressure in an artificial ear and human ear canal.

    PubMed

    Maurer, K; Schröder, K; Schäfer, E

    1984-07-01

    The measurement of sound pressure wave forms of different headphones resulted in considerable differences in an artificial ear and in the external auditory canal in man. This concerns, in particular, the pattern of stimuli used to elicit the auditory nerve and brain-stem auditory evoked potentials. By varying the electrical input to the headphones by means of a programmable stimulus generator, it can be shown that the sound pressure wave form can be influenced considerably.

  5. Sound velocity and density of liquid Fe-Ni-Si under pressure: Application to the composition of planetary molten core

    NASA Astrophysics Data System (ADS)

    Terasaki, H. G.; Kuwabara, S.; Shimoyama, Y.; Takubo, Y.; Urakawa, S.; Nishida, K.; Takeuchi, A.; Suzuki, Y.; Uesugi, K.; Watanuki, T.; Katayama, Y.; Kondo, T.; Higo, Y.

    2014-12-01

    The cores of Mercury, Mars and Moon are reported to be partially/totally molten (e.g., Margot et al. 2007, Yoder et al. 2003, Williams et al. 2001). In order to constrain the core compositions of those bodies from observed and future-planned seismic data, sound velocity and density of the core material, i.e., liquid Fe-alloy, are necessary. In this study, we have performed simultaneous measurements on these physical properties of liquid Fe-Ni-Si alloys, which is one of the major candidates for the core constituent. The effects of pressure and Si content on these properties were studied. High pressure experiments were performed using 80-ton uniaxial press designed for CT measurement or 180-ton cubic type multi-anvil press installed at BL20XU and BL22XU beamlines of SPring-8 synchrotron facility, respectively. Used samples were Fe-Ni-Si with Si content of 10-30 at%. The sample pellet was sandwiched by the single crystal sapphire buffer rod for sound velocity measurement. P-wave sound velocity was measured using pulse-echo overlapping ultrasonic method. LiNbO3 transducer was attached to the backside of the anvil to generate and receive elastic wave signals. Density was determined based on 3D volume data obtained from CT measurement or X-ray absorption profile. The P-wave velocity (VP) and density of liquid Fe-Ni-Si were successfully measured up to 2.5 GPa and 1773 K. Obtained VP of the Fe-Ni-Si is found to increase rapidly with pressure below 1 GPa and increase gradually above 1 GPa. It is also found that VP increases slightly with Si content on the density-VP plot. These trends provide a constraint on the core composition of the planets and moon by comparing with observed data.

  6. Evaluation of Round Window Stimulation Using the Floating Mass Transducer by Intracochlear Sound Pressure Measurements in Human Temporal Bones

    PubMed Central

    Nakajima, Hideko Heidi; Dong, Wei; Olson, Elizabeth S.; Rosowski, John J.; Ravicz, Michael E.; Merchant, Saumil N.

    2009-01-01

    Hypothesis Round window (RW) stimulation with a floating mass transducer (FMT) can be studied experimentally and optimized to enhance auditory transduction. Background The FMT (MED-EL Vibrant Soundbridge) has been recently implanted in patients with refractory conductive or mixed hearing loss to stimulate the RW with varying degrees of success. The mechanics of RW stimulation with the FMT have not been studied in a systematic manner. Methods In cadaveric human temporal bones, measurements of stapes velocity with laser vibrometry in response to FMT-RW stimulation were used to optimize FMT insertion. The effect of RW stimulation on hearing was estimated using simultaneous measurements of intracochlear pressures in both perilymphatic scalae with micro-optical pressure transducers. This enabled calculation of the differential pressure across the cochlear partition, which is directly tied to auditory transduction. Results The best coupling between the FMT and RW was achieved with a piece of fascia placed between the RW and the FMT, and by "bracing" the free end of the FMT against the hypotympanic wall with dental impression material. FMT-RW stimulation provided differential pressures comparable to sound-induced oval window stimulation above 1 kHz. However, below 1 kHz the FMT was less capable. Conclusions Measurements of stapes velocity and intracochlear sound pressures in scala vestibuli and scala tympani enabled experimental evaluation of FMT stimulation of the RW. The efficacy of FMT-RW coupling was influenced significantly by technical and surgical factors, which can be optimized. This temporal bone preparation also lays the foundation for future studies to investigate multiple issues of relevance to both basic and clinical science such as RW stimulation in stapes fixation, non-aerated middle-ears and third-window lesions, and to answer basic questions regarding bone conduction. PMID:19841600

  7. A displacement-pressure finite element formulation for analyzing the sound transmission in ducted shear flows with finite poroelastic lining.

    PubMed

    Nennig, Benoit; Tahar, Mabrouk Ben; Perrey-Debain, Emmanuel

    2011-07-01

    In the present work, the propagation of sound in a lined duct containing sheared mean flow is studied. Walls of the duct are acoustically treated with absorbent poroelastic foams. The propagation of elasto-acoustic waves in the liner is described by Biot's model. In the fluid domain, the propagation of sound in a sheared mean flow is governed by the Galbrun's equation. The problem is solved using a mixed displacement-pressure finite element formulation in both domains. A 3D implementation of the model has been performed and is illustrated on axisymmetric examples. Convergence and accuracy of the numerical model are shown for the particular case of the modal propagation in a infinite duct containing a uniform flow. Practical examples concerning the sound attenuation through dissipative silencers are discussed. In particular, effects of the refraction effects in the shear layer as well as the mounting conditions of the foam on the transmission loss are shown. The presence of a perforate screen at the air-porous interface is also considered and included in the model. © 2011 Acoustical Society of America

  8. Numerical Analysis of Sound Pressure Fields Focused by Phase Continuous Fresnel Lens Using Finite Difference Time Domain Method

    NASA Astrophysics Data System (ADS)

    Mori, Kazuyoshi; Miyazaki, Ayano; Ogasawara, Hanako; Nakamura, Toshiaki; Takeuchi, Yasuhito

    2007-07-01

    A convex lens using room temperature vulcanization (RTV) silicone rubber, whose acoustic impedance matches well with that of water, is a typical acoustic lens. However, some considerations are required to reduce the thickness of the lens because attenuation is very large in the RTV silicone rubber. Therefore, we have proposed a phase continuous Fresnel lens, which has some devices to keep the phase continuous in the entire lens aperture without an unequal phase on the exit side. This lens is fabricated by removing its thickness in a staircase shape in which the difference between each step is an integer multiple of wavelength. In this study, the sound fields focused by the phase continuous Fresnel lens are analyzed using a finite difference time domain (FDTD) method. Using a two-dimensional (2-D) FDTD method, we surveyed the sound pressure field of the focal region by changing the burst pulse length, angle of incidence, and frequency. Results show that the lens gain of the phase continuous Fresnel lens is greater than that of the convex lens, that focusing characteristics depend on the burst pulse length of sound source signal, and also that focal points strongly depend on frequency. In another analysis using a three-dimensional FDTD method, we found that the main lobe is the same as that indicated by 2-D analysis results and that the level outer of the main lobe is lower than that in the 2-D analysis results.

  9. Pressure-Energy Coupling, Sound Speed, and Shock Initiation Experiments on Explosives Using Pulsed Electron Beams.

    DTIC Science & Technology

    azide, KDNBF , and single crystal specimens of RDX, PETN, and lead azide. The experiments on the lead azide were unsuccessful. However, sound speed...and thermomechanical response data were obtained on the pressed pellets of KDNBF and on the single crystal specimens of RDX and PETN that allow...calculation of components of the Gruneisen tensor for these materials. Shock initiation experiments on KDNBF were also performed. (Modified author abstract)

  10. Fundamental frequency, sound pressure level and vocal dose of a vocal loading test in comparison to a real teaching situation.

    PubMed

    Echternach, Matthias; Nusseck, Manfred; Dippold, Sebastian; Spahn, Claudia; Richter, Bernhard

    2014-12-01

    Vocal loading capacity is an important aspect of vocal health, especially for people in vocally demanding occupations such as teaching. To analyze vocal loading, vocal loading tests (VLTs) or portable voice devices such as accelerometers have been used. However, it remains unclear how much a VLT in a clinical setup reflects the vocal effort of a real situation, in particular for teachers in a given classroom lesson. In this study of vocally healthy 101 student teachers, we analyzed different vocal doses for a 10-min VLT (80 dB at a distance of 30 cm) and a real 45-min teaching lesson. The phonation time, fundamental frequency, sound pressure level, and noise level were recorded using the VoxLog accelerometer/microphone system for both conditions. From these measurements the time dose, cycle dose, distance dose, energy dissipation dose, and radiated energy dose were calculated. The VLT was associated with a higher fundamental frequency, a higher sound pressure level, and higher relative phonation time compared to the real teaching lesson. Nevertheless, most vocal doses did not differ significantly between the conditions. A VLT of 10 min with >80 dB at 30 cm distance shows only small differences of vocal doses in comparison to a real teaching situation of 45 min. Thus, for clinical vocal assessment the vocal load of a VLT can be related to an approximately 45-min teaching situation.

  11. Making Sound Connections

    ERIC Educational Resources Information Center

    Deal, Walter F., III

    2007-01-01

    Sound provides and offers amazing insights into the world. Sound waves may be defined as mechanical energy that moves through air or other medium as a longitudinal wave and consists of pressure fluctuations. Humans and animals alike use sound as a means of communication and a tool for survival. Mammals, such as bats, use ultrasonic sound waves to…

  12. Making Sound Connections

    ERIC Educational Resources Information Center

    Deal, Walter F., III

    2007-01-01

    Sound provides and offers amazing insights into the world. Sound waves may be defined as mechanical energy that moves through air or other medium as a longitudinal wave and consists of pressure fluctuations. Humans and animals alike use sound as a means of communication and a tool for survival. Mammals, such as bats, use ultrasonic sound waves to…

  13. Transfer of knowledge from sound quality measurement to noise impact evaluation

    NASA Astrophysics Data System (ADS)

    Genuit, Klaus

    2004-05-01

    It is well known that the measurement and analysis of sound quality requires a complex procedure with consideration of the physical, psychoacoustical and psychological aspects of sound. Sound quality cannot be described only by a simple value based on A-weighted sound pressure level measurements. The A-weighted sound pressure level is sufficient to predict the probabilty that the human ear could be damaged by sound but the A-weighted level is not the correct descriptor for the annoyance of a complex sound situation given by several different sound events at different and especially moving positions (soundscape). On the one side, the consideration of the spectral distribution and the temporal pattern (psychoacoustics) is requested and, on the other side, the subjective attitude with respect to the sound situation, the expectation and experience of the people (psychology) have to be included in context with the complete noise impact evaluation. This paper describes applications of the newest methods of sound quality measurements-as it is well introduced at the car manufacturers-based on artifical head recordings and signal processing comparable to the human hearing used in noisy environments like community/traffic noise.

  14. Transfer of knowledge from sound quality measurement to noise impact evaluation

    NASA Astrophysics Data System (ADS)

    Genuit, Klaus

    2001-05-01

    It is well known that the measurement and analysis of sound quality requires a complex procedure with consideration of the physical, psychoacoustical and psychological aspects of sound. Sound quality cannot be described only by a simple value based on A-weighted sound pressure level measurements. The A-weighted sound pressure level is sufficient to predict the probabilty that the human ear could be damaged by sound but the A-weighted level is not the correct descriptor for the annoyance of a complex sound situation given by several different sound events at different and especially moving positions (soundscape). On the one side, the consideration of the spectral distribution and the temporal pattern (psychoacoustics) is requested and, on the other side, the subjective attitude with respect to the sound situation, the expectation and experience of the people (psychology) have to be included in context with the complete noise impact evaluation. This paper describes applications of the newest methods of sound quality measurements-as it is well introduced at the car manufacturers-based on artifical head recordings and signal processing comparable to the human hearing used in noisy environments like community/traffic noise.

  15. Dispersion and attenuation on the Brillouin sound waves of a lubricant: Di(2-ethylhexyl) sebacate under high pressures

    NASA Astrophysics Data System (ADS)

    Fujita, Yoshitaka; Kobayashi, Hiroshi

    2011-08-01

    The Brillouin spectra of di(2-ethylhexyl) sebacate, which is a liquid lubricant known as DOS, were measured at up to 5 GPa at 25 °C and up to 2.5 GPa at 80 °C. At 25 °C, the Brillouin frequency linewidth (acoustic attenuation) has a large maximum at 0.1 MPa, and at 80 °C, it has a large broad maximum at 0.8 GPa. The Brillouin frequency shift (sound velocity) and linewidth obtained indicate that the large dispersion of the sound velocities of DOS occurs from 0.1 MPa at 25 °C and from 0.8 GPa at 80 °C. The origins of this attenuation and dispersion are discussed on the basis of the theory for a viscoelastic liquid. It is proposed that the large acoustic attenuation and dispersion of DOS are due to the production of higher-rank structures with nano-order domains in a polymeric liquid by pressurization. The results show that DOS is strongly viscoelastic above 0.8 GPa at 80 °C, but it is not viscous below 0.8 GPa at 80 °C, with the disappearance of the frequency dispersion. The result obtained is used to explain a limiting shear stress observed in a traction oil. Above a given sliding speed, the oil reaches the region of temperature and pressure in which its viscosity decreases with increasing shear rate and conveys a constant torque above some high shear rate. Then, the oil flows as a plastic solid at a limiting shear stress. These findings regarding the dynamical properties of DOS under high pressures are very useful for the production and analysis of lubricants and traction oils.

  16. Towards direct realisation of the SI unit of sound pressure in the audible hearing range based on optical free-field acoustic particle measurements

    NASA Astrophysics Data System (ADS)

    Koukoulas, Triantafillos; Piper, Ben

    2015-04-01

    Since the introduction of the International System of Units (the SI system) in 1960, weights, measures, standardised approaches, procedures, and protocols have been introduced, adapted, and extensively used. A major international effort and activity concentrate on the definition and traceability of the seven base SI units in terms of fundamental constants, and consequently those units that are derived from the base units. In airborne acoustical metrology and for the audible range of frequencies up to 20 kHz, the SI unit of sound pressure, the pascal, is realised indirectly and without any knowledge or measurement of the sound field. Though the principle of reciprocity was originally formulated by Lord Rayleigh nearly two centuries ago, it was devised in the 1940s and eventually became a calibration standard in the 1960s; however, it can only accommodate a limited number of acoustic sensors of specific types and dimensions. International standards determine the device sensitivity either through coupler or through free-field reciprocity but rely on the continuous availability of specific acoustical artefacts. Here, we show an optical method based on gated photon correlation spectroscopy that can measure sound pressures directly and absolutely in fully anechoic conditions, remotely, and without disturbing the propagating sound field. It neither relies on the availability or performance of any measurement artefact nor makes any assumptions of the device geometry and sound field characteristics. Most importantly, the required units of sound pressure and microphone sensitivity may now be experimentally realised, thus providing direct traceability to SI base units.

  17. Towards direct realisation of the SI unit of sound pressure in the audible hearing range based on optical free-field acoustic particle measurements

    SciTech Connect

    Koukoulas, Triantafillos Piper, Ben

    2015-04-20

    Since the introduction of the International System of Units (the SI system) in 1960, weights, measures, standardised approaches, procedures, and protocols have been introduced, adapted, and extensively used. A major international effort and activity concentrate on the definition and traceability of the seven base SI units in terms of fundamental constants, and consequently those units that are derived from the base units. In airborne acoustical metrology and for the audible range of frequencies up to 20 kHz, the SI unit of sound pressure, the pascal, is realised indirectly and without any knowledge or measurement of the sound field. Though the principle of reciprocity was originally formulated by Lord Rayleigh nearly two centuries ago, it was devised in the 1940s and eventually became a calibration standard in the 1960s; however, it can only accommodate a limited number of acoustic sensors of specific types and dimensions. International standards determine the device sensitivity either through coupler or through free-field reciprocity but rely on the continuous availability of specific acoustical artefacts. Here, we show an optical method based on gated photon correlation spectroscopy that can measure sound pressures directly and absolutely in fully anechoic conditions, remotely, and without disturbing the propagating sound field. It neither relies on the availability or performance of any measurement artefact nor makes any assumptions of the device geometry and sound field characteristics. Most importantly, the required units of sound pressure and microphone sensitivity may now be experimentally realised, thus providing direct traceability to SI base units.

  18. Narrow sound pressure level tuning in the auditory cortex of the bats Molossus molossus and Macrotus waterhousii.

    PubMed

    Macías, Silvio; Hechavarría, Julio C; Cobo, Ariadna; Mora, Emanuel C

    2014-03-01

    In the auditory system, tuning to sound level appears in the form of non-monotonic response-level functions that depict the response of a neuron to changing sound levels. Neurons with non-monotonic response-level functions respond best to a particular sound pressure level (defined as "best level" or level evoking the maximum response). We performed a comparative study on the location and basic functional organization of the auditory cortex in the gleaning bat, Macrotus waterhousii, and the aerial-hawking bat, Molossus molossus. Here, we describe the response-level function of cortical units in these two species. In the auditory cortices of M. waterhousii and M. molossus, the characteristic frequency of the units increased from caudal to rostral. In M. waterhousii, there was an even distribution of characteristic frequencies while in M. molossus there was an overrepresentation of frequencies present within echolocation pulses. In both species, most of the units showed best levels in a narrow range, without an evident topography in the amplitopic organization, as described in other species. During flight, bats decrease the intensity of their emitted pulses when they approach a prey item or an obstacle resulting in maintenance of perceived echo intensity. Narrow level tuning likely contributes to the extraction of echo amplitudes facilitating echo-intensity compensation. For aerial-hawking bats, like M. molossus, receiving echoes within the optimal sensitivity range can help the bats to sustain consistent analysis of successive echoes without distortions of perception caused by changes in amplitude. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Trailing Edge Flow and Aerodynamic Sound. Part 1. Tonal Pressure and Velocity Fluctuations. Part 2. Random Pressure and Velocity Fluctuations.

    DTIC Science & Technology

    1984-12-01

    velocimetry techniques, so hot- wire anemometry was used for wake traverses. The high speeds and high Reynolds numbers made the use of flow visualization ...and Hall (1970) will be used. Thus, the reduced soun ( pressure at X is P (X, w) = . . dV(F) (22)a JJ o °3tc 𔃼 where the integral extends over the...structures in the absence of sophisti- ated flow- visualization techniques. ’.1 FURBULENT FIOW NEAR 250 KNUCKLE-BEVELED EDGE As the boundary layer

  20. Sound quality assessment of Diesel combustion noise using in-cylinder pressure components

    NASA Astrophysics Data System (ADS)

    Payri, F.; Broatch, A.; Margot, X.; Monelletta, L.

    2009-01-01

    The combustion process in direct injection (DI) Diesel engines is an important source of noise, and it is thus the main reason why end-users could be reluctant to drive vehicles powered with this type of engine. This means that the great potential of Diesel engines for environment preservation—due to their lower consumption and the subsequent reduction of CO2 emissions—may be lost. Moreover, the advanced combustion concepts—e.g. the HCCI (homogeneous charge compression ignition)—developed to comply with forthcoming emissions legislation, while maintaining the efficiency of current engines, are expected to be noisier because they are characterized by a higher amount of premixed combustion. For this reason many efforts have been dedicated by car manufacturers in recent years to reduce the overall level and improve the sound quality of engine noise. Evaluation procedures are required, both for noise levels and sound quality, that may be integrated in the global engine development process in a timely and cost-effective manner. In previous published work, the authors proposed a novel method for the assessment of engine noise level. A similar procedure is applied in this paper to demonstrate the suitability of combustion indicators for the evaluation of engine noise quality. These indicators, which are representative of the peak velocity of fuel burning and the resonance in the combustion chamber, are well correlated with the combustion noise mark obtained from jury testing. Quite good accuracy in the prediction of the engine noise quality has been obtained with the definition of a two-component regression, which also permits the identification of the combustion process features related to the resulting noise quality, so that corrective actions may be proposed.

  1. Sound velocity of Fe-S liquids at high pressure: Implications for the Moon's molten outer core

    SciTech Connect

    Jing, Zhicheng; Wang, Yanbin; Kono, Yoshio; Yu, Tony; Sakamaki, Tatsuya; Park, Changyong; Rivers, Mark L.; Sutton, Stephen R.; Shen, Guoyin

    2014-07-21

    Sound velocities of Fe and Fe–S liquids were determined by combining the ultrasonic measurements and synchrotron X-ray techniques under high pressure–temperature conditions from 1 to 8 GPa and 1573 K to 1973 K. Four different liquid compositions were studied including Fe, Fe–10 wt% S, Fe–20 wt% S, and Fe–27 wt% S. Our data show that the velocity of Fe-rich liquids increases upon compression and decreases with increasing sulfur content, whereas temperature has negligible effect on the velocity of Fe–S liquids. The sound velocity data were combined with ambient-pressure densities to fit the Murnaghan equation of state (EOS). Compared to the lunar seismic model, our velocity data constrain the sulfur content at 4±3 wt%, indicating a significantly denser (6.5±0.5 g/cm3) and hotter (1870-70+100 K) outer core than previously estimated. A new lunar structure model incorporating available geophysical observations points to a smaller core radius. Our model suggests a top–down solidification scenario for the evolution of the lunar core. Such “iron snow” process may have been an important mechanism for the growth of the inner core.

  2. Method of and apparatus for measuring temperature and pressure. [atmospheric sounding

    NASA Technical Reports Server (NTRS)

    Korb, C. L.; Kalshoven, J. E., Jr. (Inventor)

    1985-01-01

    Laser beams are transmitted through gas to a reflecting target, which may be either a solid surface or particulate matter in gas or the gas molecules. The return beams are measured to determine the amount of energy absorbed by the gas. For temperature measurements, the laser beam has a wavelength at which the gas exhibits a relatively temperature sensitive and pressure insensitive absorption characteristic for pressure measurements, the laser beam has a wavelength at which the gas has a relatively pressure sensitive and temperature insensitive absorption characteristic. To reduce the effects of scattering on the absorption measurements a reference laser beam with a weak absorption characteristic is transmitted colinearly with the data beam having a strong absorption characteristic. The two signals are processed as a ratio to eliminate back scattering. Embodiments of transmitters and receivers described include a sequential laser pulse transmitter and receiver, a simultaneous laser pulse transmitter and receiver.

  3. Sound Velocity of Fe and Fe-Si Alloys at Mbar Pressures by a Multi-Technique Approach

    NASA Astrophysics Data System (ADS)

    Antonangeli, D.; Morard, G.; Decremps, F.; Gauthier, M.; Murphy, C. A.; Fiquet, G.; Fei, Y.

    2015-12-01

    The presence of light elements alloyed to iron in the Earth's core is well established, and many studies point at silicon as the major light element in the inner core. However, attempts to constrain Si abundance on the basis of comparison of measured velocities in Fe-Si alloys at high pressure with seismic observations do not provide a unique answer. Available data obtained in the 40-100 GPa range are indeed limited in number and, more importantly, in open disagreement. Here we present new data on pure Fe and on Fe-Si alloys in the hcp structure at pressure exceeding 100 GPa, obtained by inelastic x-ray scattering and by picosecond acoustic measurements. The comparison of measurements by these complementary techniques provides reliable relations for the pressure and density evolution of the compressional sound velocity of the investigated alloys. These results are compared to results in literature and allow us to model the effect of Si content on the velocity-density relationship in the Fe-FeSi system and to constrain the Si abundance in the Earth's inner core.

  4. [Hearing loss by continuous exposure to high sound pressure among maintenance workers at a Brazilian Air Force helicopters unity].

    PubMed

    Ribeiro, Ana Maria Dutra; Câmara, Volney de M

    2006-06-01

    Continuous exposure to high sound pressure in aeronautical workers can be associated with inner ear hearing loss. This study aims to evaluate the prevalence of deafness among all maintenance workers from a Brazilian Air Force helicopter unit. The methods included the application of individual questionnaires and audiometric tests. The results showed a high prevalence (32.4%) of hearing loss related to time on the job (p < 0.05; RP = 2.11; 95%CI: 1.03-4.32) and the 41-50-year age bracket (p = 0.00; RP < 3.94; 95%CI: 2.04-7.62). No influence was found from selected variables that might result in bias. Finally, a program to prevent hearing loss was recommended.

  5. Effects of training on time-varying spectral energy and sound pressure level in nine male classical singers.

    PubMed

    Ferguson, Sam; Kenny, Dianna T; Cabrera, Densil

    2010-01-01

    The male classical singing voice is a musical instrument that is very important in western culture. It has many acoustic features which should change and improve over the period in which the singer trains. In this study we compare nine singers in different stages of training, from university level students through to international soloists. Typically, Energy Ratio (ER; a measure of mean spectral slope) and mean sound pressure level (SPL) may be calculated to summarize an entire singing sample. We investigate an alternative approach, by calculating the time-varying ER and SPL. The inspection of the distribution of these descriptors over an aria's time period yields a more detailed picture of the strategies for high-frequency energy production used by singers with different levels of training. Copyright 2010 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  6. Sound Effects: Social Pressure and Identity Negotiation in the Spanish Language Classroom

    ERIC Educational Resources Information Center

    Lefkowitz, Natalie; Hedgcock, John S.

    2006-01-01

    This study explores how social pressure and identity construction patterns interact with the oral performance of secondary and post-secondary learners of Spanish as a foreign language. Data derive from 268 questionnaires probing students' perceptions of Spanish, Spanish speakers, their peers, and their instructors. Ethnographic interviews…

  7. Sound Effects: Social Pressure and Identity Negotiation in the Spanish Language Classroom

    ERIC Educational Resources Information Center

    Lefkowitz, Natalie; Hedgcock, John S.

    2006-01-01

    This study explores how social pressure and identity construction patterns interact with the oral performance of secondary and post-secondary learners of Spanish as a foreign language. Data derive from 268 questionnaires probing students' perceptions of Spanish, Spanish speakers, their peers, and their instructors. Ethnographic interviews…

  8. High levels of sound pressure: acoustic reflex thresholds and auditory complaints of workers with noise exposure.

    PubMed

    Duarte, Alexandre Scalli Mathias; Ng, Ronny Tah Yen; de Carvalho, Guilherme Machado; Guimarães, Alexandre Caixeta; Pinheiro, Laiza Araujo Mohana; Costa, Everardo Andrade da; Gusmão, Reinaldo Jordão

    2015-01-01

    The clinical evaluation of subjects with occupational noise exposure has been difficult due to the discrepancy between auditory complaints and auditory test results. This study aimed to evaluate the contralateral acoustic reflex thresholds of workers exposed to high levels of noise, and to compare these results to the subjects' auditory complaints. This clinical retrospective study evaluated 364 workers between 1998 and 2005; their contralateral acoustic reflexes were compared to auditory complaints, age, and noise exposure time by chi-squared, Fisher's, and Spearman's tests. The workers' age ranged from 18 to 50 years (mean=39.6), and noise exposure time from one to 38 years (mean=17.3). We found that 15.1% (55) of the workers had bilateral hearing loss, 38.5% (140) had bilateral tinnitus, 52.8% (192) had abnormal sensitivity to loud sounds, and 47.2% (172) had speech recognition impairment. The variables hearing loss, speech recognition impairment, tinnitus, age group, and noise exposure time did not show relationship with acoustic reflex thresholds; however, all complaints demonstrated a statistically significant relationship with Metz recruitment at 3000 and 4000Hz bilaterally. There was no significance relationship between auditory complaints and acoustic reflexes. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  9. Outer ear canal sound pressure and bone vibration measurement in SSD and CHL patients using a transcutaneous bone conduction instrument.

    PubMed

    Ghoncheh, Mohammad; Lilli, Giorgio; Lenarz, Thomas; Maier, Hannes

    2016-10-01

    The intraoperative and postoperative objective functional assessment of transcutaneous bone conduction implants is still a challenge. Here we compared intraoperative Laser-Doppler-vibrometry (LDV, Polytec Inc.) to measure vibration of the bone close to the implant to Outer Ear Canal Sound Pressure Level (OEC-SPL) measurements. Twelve single sided deafness (SSD) patients with contralateral intact ossicular chains and eight bilateral conductive hearing loss (CHL) patients were included in the study. SSD patients had a minor average air-bone-gap (ABG) of 0.4 ± 0.4 dB (0.5, 1, 2, 4 kHz mean value (MV) ± standard deviation (SD)) on the contralateral side where a normal transmission between cochlea and the tympanic membrane can be assumed. CHL patients had an impaired middle ear transmission with a mean ABG of 46.0 ± 7.9 dB (MV±SD). Vibration and OEC-SPL responses could reliably be recorded with a minimal signal-to-noise ratio of at least 12 dB. Average OEC-SPL on the contralateral side and intraoperative vibration measurements were strongly correlated in SSD (r(2) = 0.75) and CHL (r(2) = 0.86) patients. The correlation in individual results between OEC-SPL and vibration measurements was weak, indicating some underlying inter-individual variability. The high correlation of average responses showed that OEC-SPL are closely linked to bone vibration, although both cannot be equivalently used for intraoperative testing due to the high variability in individual results. On the other hand, OEC-SPL provides an easy and affordable measurement tool to monitor stability and functionality postoperatively using individual reference measurements. We observed no significant differences (t-test, p < 0.05) by comparing results from contralateral OEC-SPL in twelve SSD and eight CHL patients at frequencies between 0.5 and 8 kHz. This implies that the part of the measured sound pressure in the ear canal originating from the cochlea and emitted by the tympanic is not

  10. Respiratory Muscle Strength, Sound Pressure Level, and Vocal Acoustic Parameters and Waist Circumference of Children With Different Nutritional Status.

    PubMed

    Pascotini, Fernanda dos Santos; Ribeiro, Vanessa Veis; Christmann, Mara Keli; Tomasi, Lidia Lis; Dellazzana, Amanda Alves; Haeffner, Leris Salete Bonfanti; Cielo, Carla Aparecida

    2016-01-01

    Relate respiratory muscle strength (RMS), sound pressure (SP) level, and vocal acoustic parameters to the abdominal circumference (AC) and nutritional status of children. This is a cross-sectional study. Eighty-two school children aged between 8 and 10 years, grouped by nutritional states (eutrophic, overweight, or obese) and AC percentile (≤25, 25-75, and ≥75), were included in the study. Evaluations of maximal inspiratory pressure (IPmax) and maximal expiratory pressure (EPmax) were conducted using the manometer and SP and acoustic parameters through the Multi-Dimensional Voice Program Advanced (KayPENTAX, Montvale, New Jersey). There were significant differences (P < 0.05) in the EPmax of children with AC between the 25th and 75th percentiles (72.4) and those less than or equal to the 25th percentile (61.9) and in the SP of those greater than or equal to the 75th percentile (73.4) and less than or equal to the 25th percentile (66.6). The IPmax, EPmax, SP levels, and acoustic variables were not different in relation to the nutritional states of the children. There was a strong and positive correlation between the coefficient of amplitude perturbations (shimmer), the harmonics-to-noise ratio and the variation of the fundamental frequency, respectively, 0.79 and 0.71. RMS and acoustic voice characteristics in children do not appear to be influenced by nutritional states, and respiratory pressure does not interfere with acoustic voice characteristics. However, localized fat, represented by the AC, alters the EPmax and the SP, each of which increases as the AC increases. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  11. Sound Localization in Lizards: Functioning of a Pressure-Gradient Receiver

    NASA Astrophysics Data System (ADS)

    van Hemmen, J. Leo

    2009-03-01

    Because of their small interaural distance, lizards as well as some other animals have developed a special hearing mechanism, the ``pressure-gradient receiver''. The lizard peripheral auditory system differs from the mammalian one by a coupling of the two eardrums through the internal mouth cavity. We present a three-dimensional analytical model of the pressure-gradient receiver. The central aspect of the coupling of the membranes through the mouth cavity is realized by means of the boundary conditions. Moreover, the lizard's middle ear, a simple lever construction called columella, is asymmetrically attached to the tympanic membrane. This has motivated us to solve the problem of how the middle ear influences the spatial-amplitude profile and the frequency distribution of the tympanic membrane vibration. Finally, we show results from numerical simulations of the eigenfunctions and eigenfrequencies in a lizard's internal mouth cavity bounded by the eardrums. To this end, we have constructed the complex geometry from a cast imprint of the cavity with the help of three-dimensional scans. Our results led to an interesting speculation regarding the neurobiological use of the pressure-gradient system.

  12. Statistical Analysis for Subjective and Objective Evaluations of Dental Drill Sounds

    PubMed Central

    Yamada, Tomomi; Kuwano, Sonoko; Ebisu, Shigeyuki; Hayashi, Mikako

    2016-01-01

    The sound produced by a dental air turbine handpiece (dental drill) can markedly influence the sound environment in a dental clinic. Indeed, many patients report that the sound of a dental drill elicits an unpleasant feeling. Although several manufacturers have attempted to reduce the sound pressure levels produced by dental drills during idling based on ISO 14457, the sound emitted by such drills under active drilling conditions may negatively influence the dental clinic sound environment. The physical metrics related to the unpleasant impressions associated with dental drill sounds have not been determined. In the present study, psychological measurements of dental drill sounds were conducted with the aim of facilitating improvement of the sound environment at dental clinics. Specifically, we examined the impressions elicited by the sounds of 12 types of dental drills in idling and drilling conditions using a semantic differential. The analysis revealed that the impressions of dental drill sounds varied considerably between idling and drilling conditions and among the examined drills. This finding suggests that measuring the sound of a dental drill in idling conditions alone may be insufficient for evaluating the effects of the sound. We related the results of the psychological evaluations to those of measurements of the physical metrics of equivalent continuous A-weighted sound pressure levels (LAeq) and sharpness. Factor analysis indicated that impressions of the dental drill sounds consisted of two factors: “metallic and unpleasant” and “powerful”. LAeq had a strong relationship with “powerful impression”, calculated sharpness was positively related to “metallic impression”, and “unpleasant impression” was predicted by the combination of both LAeq and calculated sharpness. The present analyses indicate that, in addition to a reduction in sound pressure level, refining the frequency components of dental drill sounds is important for creating

  13. Statistical Analysis for Subjective and Objective Evaluations of Dental Drill Sounds.

    PubMed

    Yamada, Tomomi; Kuwano, Sonoko; Ebisu, Shigeyuki; Hayashi, Mikako

    2016-01-01

    The sound produced by a dental air turbine handpiece (dental drill) can markedly influence the sound environment in a dental clinic. Indeed, many patients report that the sound of a dental drill elicits an unpleasant feeling. Although several manufacturers have attempted to reduce the sound pressure levels produced by dental drills during idling based on ISO 14457, the sound emitted by such drills under active drilling conditions may negatively influence the dental clinic sound environment. The physical metrics related to the unpleasant impressions associated with dental drill sounds have not been determined. In the present study, psychological measurements of dental drill sounds were conducted with the aim of facilitating improvement of the sound environment at dental clinics. Specifically, we examined the impressions elicited by the sounds of 12 types of dental drills in idling and drilling conditions using a semantic differential. The analysis revealed that the impressions of dental drill sounds varied considerably between idling and drilling conditions and among the examined drills. This finding suggests that measuring the sound of a dental drill in idling conditions alone may be insufficient for evaluating the effects of the sound. We related the results of the psychological evaluations to those of measurements of the physical metrics of equivalent continuous A-weighted sound pressure levels (LAeq) and sharpness. Factor analysis indicated that impressions of the dental drill sounds consisted of two factors: "metallic and unpleasant" and "powerful". LAeq had a strong relationship with "powerful impression", calculated sharpness was positively related to "metallic impression", and "unpleasant impression" was predicted by the combination of both LAeq and calculated sharpness. The present analyses indicate that, in addition to a reduction in sound pressure level, refining the frequency components of dental drill sounds is important for creating a comfortable sound

  14. Indoor seismology by probing the Earth's interior by using sound velocity measurements at high pressures and temperatures.

    PubMed

    Li, Baosheng; Liebermann, Robert C

    2007-05-29

    The adiabatic bulk (K(S)) and shear (G) moduli of mantle materials at high pressure and temperature can be obtained directly by measuring compressional and shear wave velocities in the laboratory with experimental techniques based on physical acoustics. We present the application of the current state-of-the-art experimental techniques by using ultrasonic interferometry in conjunction with synchrotron x radiation to study the elasticity of olivine and pyroxenes and their high-pressure phases. By using these updated thermoelasticity data for these phases, velocity and density profiles for a pyrolite model are constructed and compared with radial seismic models. We conclude that pyrolite provides an adequate explanation of the major seismic discontinuities at 410- and 660-km depths, the gradient in the transition zone, as well as the velocities in the lower mantle, if the uncertainties in the modeling and the variations in different seismic models are considered. The characteristics of the seismic scaling factors in response to thermal anomalies suggest that anticorrelations between bulk sound and shear wave velocities, as well as the large positive density anomalies observed in the lower mantle, cannot be explained fully without invoking chemical variations.

  15. Indoor seismology by probing the Earth interior by using sound velocity measurements at high pressures and temperatures

    SciTech Connect

    Li,B.; Liebermann, R.

    2007-01-01

    The adiabatic bulk (K S) and shear (G) moduli of mantle materials at high pressure and temperature can be obtained directly by measuring compressional and shear wave velocities in the laboratory with experimental techniques based on physical acoustics. We present the application of the current state-of-the-art experimental techniques by using ultrasonic interferometry in conjunction with synchrotron x radiation to study the elasticity of olivine and pyroxenes and their high-pressure phases. By using these updated thermoelasticity data for these phases, velocity and density profiles for a pyrolite model are constructed and compared with radial seismic models. We conclude that pyrolite provides an adequate explanation of the major seismic discontinuities at 410- and 660-km depths, the gradient in the transition zone, as well as the velocities in the lower mantle, if the uncertainties in the modeling and the variations in different seismic models are considered. The characteristics of the seismic scaling factors in response to thermal anomalies suggest that anticorrelations between bulk sound and shear wave velocities, as well as the large positive density anomalies observed in the lower mantle, cannot be explained fully without invoking chemical variations.

  16. Sound wave velocities of Fe-Ni alloy at high pressure and temperature

    NASA Astrophysics Data System (ADS)

    Kantor, A.; Dubrovinsky, L.; Kantor, I.; Kurnosov, A.; Kuznetsov, A.; Dubrovinskaia, N.; Krisch, M.

    2006-12-01

    Knowledge of high-pressure and high-temperature elasticity of Fe-Ni alloy with low (5-25%) Ni content is crucial for geosciences since it is probably the major component of the core of the Earth, Mars, Mercury, Moon, satellites of Saturn and Jupiter. High-pressure and high-temperature (up to 41 GPa and 700 K) study of FeNi alloy with 22% of Ni was carried out by mean of inelastic X-ray scattering (IXS) from polycrystalline material. Two sets of experiments: at room temperature and at 700 K have been performed. Before and after every measurement (taking about 10 hours) an in-situ 1-D monochromatic X-ray diffraction pattern was collected for volume determination exactly from the sample. X-ray diffraction study revealed stability of fcc over hcp phase in the whole studied P,T range. Isothermal equation of state was derived at room temperature and at 700 K. X-ray inelastic scattering measurements allow to calculate longitudinal acoustic wave velocity VL, that gives, combined with measured equations of state, full isotropic elasticity of the material. We did not observe strong deviations of fcc iron-nickel alloy bulk elasticity from elastic properties of pure hcp iron.

  17. Neuropeptide Y promoter polymorphism modifies effects of a weight-loss diet on 2-year changes of blood pressure: the preventing overweight using novel dietary strategies trial.

    PubMed

    Zhang, Xiaomin; Qi, Qibin; Liang, Jun; Hu, Frank B; Sacks, Frank M; Qi, Lu

    2012-11-01

    Neuropeptide Y (NPY) is implicated in the regulation of blood pressure (BP), and NPY pathways in the hypothalamus are sensitive to dietary fat. We evaluated the potential effect of a functional variant rs16147 located in the NPY gene promoter region on the association between 2-year diet intervention and change in multiple BP measures in the randomized Preventing Overweight Using Novel Dietary Strategies Trial. The NPY rs16147 was genotyped in 723 obese adults who were randomly assigned to 1 of 4 diets differing in the target percentages of energy derived from fat, protein, and carbohydrate. The changes of 4 BP phenotypes, including systolic BP, diastolic BP, pulse pressure, and mean arterial pressure, during 2-year diet intervention were analyzed. In the total participants and participants with hypertension, we observed significant and consistent interactions between rs16147 genotype and dietary fat intake on changes in multiple BP phenotypes at 2 years (all P for interactions <0.05). The risk allele (C allele) was associated with a greater reduction of BP phenotypes in response to low-fat diet, whereas an opposite genetic effect was observed in response to high-fat diet. In addition, the C allele was related to greater changes in 4 BP phenotypes in hypertensive compared with nonhypertensive participants. Our data suggest that NPY rs16147 may modulate the association between dietary fat intake and changes in BP phenotypes, and the C allele exerts a long-term beneficial effect on lowering BP in response to low-fat diet in obese and hypertensive subjects.

  18. Measurements of Speed of Sound in Lean and Rich Natural Gas Mixtures at Pressures up to 37 MPa Using a Specialized Rupture Tube

    NASA Astrophysics Data System (ADS)

    Botros, K. K.

    2010-12-01

    Measurements of the speed of sound in 42 different compositions of lean, medium, and rich natural-gas mixtures using a specialized high-pressure rupture tube have been conducted. The rupture tube is made of stainless steel (internal diameter = 38.1 mm and length = 42 m), and is instrumented with 13 high-frequency-response dynamic pressure transducers (Endevco) mounted very close to the rupture end and along the length of the tube to capture the pressure-time traces of the decompression wave. Tests were conducted for initial pressures ranging from 10 MPa to 37 MPa and a temperature range from -25°C to+68°C. Gas mixture compositions were controlled by mixing conventional natural-gas mixtures from an adjacent gas pipeline with richer components of alkanes. Temperature control is achieved by a heat tracer along the tube with a set point at the desired gas temperature of the particular test. Uncertainty analysis indicated that the uncertainty in the experimentally determined speed of sound in the undisturbed gas mixture at the initial pressure and temperature is on the order of 0.306 %. The measured speeds of sound were compared to predictions by five equations of state, namely; the Benedict-Webb-Rubin-Starling (BWRS), AGA-8, Peng-Robinson (PR), Redlich-Kwong-Soave (RK-Soave), and Groupe Européen de Recherches Gaziéres (GERG-2004) equations.

  19. Rare-gas liquids - Equation of state and reduced-pressure, reduced-bulk-modulus, and reduced-sound-velocity functions

    NASA Technical Reports Server (NTRS)

    Schlosser, Herbert

    1990-01-01

    This paper is concerned with verification of the applicability of the Vinet et al. (1987) universal equation of state to the liquid phase of the rare-gas elements under pressure. As previously observed in solids and liquids metals, to a good approximation, in the absence of phase transitions, plots of the logarithms of the reduced pressure function, of the reduced sound velocity, and of the reduced bulk modulus, are all linear functions of 1 - X over the entire experimental pressure range. The results obtained on the rare-gas liquids are comparable in accuracy to those obtained in previous work on solids and liquid metals.

  20. Rare-gas liquids - Equation of state and reduced-pressure, reduced-bulk-modulus, and reduced-sound-velocity functions

    NASA Technical Reports Server (NTRS)

    Schlosser, Herbert

    1990-01-01

    This paper is concerned with verification of the applicability of the Vinet et al. (1987) universal equation of state to the liquid phase of the rare-gas elements under pressure. As previously observed in solids and liquids metals, to a good approximation, in the absence of phase transitions, plots of the logarithms of the reduced pressure function, of the reduced sound velocity, and of the reduced bulk modulus, are all linear functions of 1 - X over the entire experimental pressure range. The results obtained on the rare-gas liquids are comparable in accuracy to those obtained in previous work on solids and liquid metals.

  1. Offshore exposure experiments on cuttlefish indicate received sound pressure and particle motion levels associated with acoustic trauma.

    PubMed

    Solé, Marta; Sigray, Peter; Lenoir, Marc; van der Schaar, Mike; Lalander, Emilia; André, Michel

    2017-04-05

    Recent findings on cephalopods in laboratory conditions showed that exposure to artificial noise had a direct consequence on the statocyst, sensory organs, which are responsible for their equilibrium and movements in the water column. The question remained about the contribution of the consequent near-field particle motion influence from the tank walls, to the triggering of the trauma. Offshore noise controlled exposure experiments (CEE) on common cuttlefish (Sepia officinalis), were conducted at three different depths and distances from the source and particle motion and sound pressure measurements were performed at each location. Scanning electron microscopy (SEM) revealed injuries in statocysts, which severity was quantified and found to be proportional to the distance to the transducer. These findings are the first evidence of cephalopods sensitivity to anthropogenic noise sources in their natural habitat. From the measured received power spectrum of the sweep, it was possible to determine that the animals were exposed at levels ranging from 139 to 142 dB re 1 μPa(2) and from 139 to 141 dB re 1 μPa(2), at 1/3 octave bands centred at 315 Hz and 400 Hz, respectively. These results could therefore be considered a coherent threshold estimation of noise levels that can trigger acoustic trauma in cephalopods.

  2. On the efficacy of spatial sampling using manual scanning paths to determine the spatial average sound pressure level in rooms.

    PubMed

    Hopkins, Carl

    2011-05-01

    In architectural acoustics, noise control and environmental noise, there are often steady-state signals for which it is necessary to measure the spatial average, sound pressure level inside rooms. This requires using fixed microphone positions, mechanical scanning devices, or manual scanning. In comparison with mechanical scanning devices, the human body allows manual scanning to trace out complex geometrical paths in three-dimensional space. To determine the efficacy of manual scanning paths in terms of an equivalent number of uncorrelated samples, an analytical approach is solved numerically. The benchmark used to assess these paths is a minimum of five uncorrelated fixed microphone positions at frequencies above 200 Hz. For paths involving an operator walking across the room, potential problems exist with walking noise and non-uniform scanning speeds. Hence, paths are considered based on a fixed standing position or rotation of the body about a fixed point. In empty rooms, it is shown that a circle, helix, or cylindrical-type path satisfy the benchmark requirement with the latter two paths being highly efficient at generating large number of uncorrelated samples. In furnished rooms where there is limited space for the operator to move, an efficient path comprises three semicircles with 45°-60° separations.

  3. Effects of altered fundamental frequency on nasalance during vowel production by adult speakers at targeted sound pressure levels.

    PubMed

    Mandulak, Kerry C; Zajac, David J

    2009-01-01

    This study investigated the effects of altered fundamental frequency (F0) on nasalance levels of the vowels /i/ and /a/ produced by adults without cleft palate within a controlled sound pressure level (SPL) range. A prospective group design with convenience sampling from the University of North Carolina at Chapel Hill was used. 20 men and 20 women participated, aged 18 to 55 years. All were native English speakers with normal speech and language skills and adequate velopharyngeal function. The outcome measures were percentage nasalance obtained from the Nasometer 6200 (KayPentax) headset and the Computerized Speech Lab Model 4400 (CSL, KayPentax) during vowel production while speakers (1) targeted an SPL range of 75 to 85 dB and (2) targeted the SPL plus F0 range of 165 to 175 Hz. A significant univariate effect was found for the vowels /i/ and /a/ in the targeted SPL condition such that /i/ was produced with higher nasalance than /a/. A significant univariate effect was also found during production of /a/ in the targeted SPL plus F0 condition such that men produced /a/ with higher nasalance than women did. SPL appears to largely account for percentage nasalance differences between the vowels /i/ and /a/ produced by adult male and female speakers. Increased F0 by male speakers appears to influence percentage nasalance during production of the vowel /a/. Clinical implications in regard to assessment of hypernasality are discussed.

  4. Offshore exposure experiments on cuttlefish indicate received sound pressure and particle motion levels associated with acoustic trauma

    NASA Astrophysics Data System (ADS)

    Solé, Marta; Sigray, Peter; Lenoir, Marc; van der Schaar, Mike; Lalander, Emilia; André, Michel

    2017-04-01

    Recent findings on cephalopods in laboratory conditions showed that exposure to artificial noise had a direct consequence on the statocyst, sensory organs, which are responsible for their equilibrium and movements in the water column. The question remained about the contribution of the consequent near-field particle motion influence from the tank walls, to the triggering of the trauma. Offshore noise controlled exposure experiments (CEE) on common cuttlefish (Sepia officinalis), were conducted at three different depths and distances from the source and particle motion and sound pressure measurements were performed at each location. Scanning electron microscopy (SEM) revealed injuries in statocysts, which severity was quantified and found to be proportional to the distance to the transducer. These findings are the first evidence of cephalopods sensitivity to anthropogenic noise sources in their natural habitat. From the measured received power spectrum of the sweep, it was possible to determine that the animals were exposed at levels ranging from 139 to 142 dB re 1 μPa2 and from 139 to 141 dB re 1 μPa2, at 1/3 octave bands centred at 315 Hz and 400 Hz, respectively. These results could therefore be considered a coherent threshold estimation of noise levels that can trigger acoustic trauma in cephalopods.

  5. Sound pressure level and spectral balance linearity and symmetry in the messa di voce of female classical singers.

    PubMed

    Collyer, Sally; Davis, Pamela J; Thorpe, C William; Callaghan, Jean

    2007-03-01

    The messa di voce, in its pure form a crescendo and decrescendo on one note, has been revered for centuries in classical singing, but the pedagogical assumptions of linearity and symmetry have received little critical assessment, especially across a wide fundamental frequency (F0) range. Five trained female classical singers performed a total of 318 messe di voce across their musical F0 range to identify its acoustical characteristics and the influence of F0. Sound pressure level (SPL) range was generally greater during crescendo at higher F0's and during decrescendo at lower FO's. Change in SPL during the messa di voce was predominantly nonlinear, and the shape of the SPL traces differed greatly between crescendo and decrescendo. Nonlinearity in SPL change was not related to SPL range but did show a F0 influence in decrescendo. Change in spectral balance (0-2 vs. 2-4 kHz) with respect to SPL change showed markedly more symmetry than linearity, so that changes in the mode of phonation during the messa di voce were dependent upon SPL regardless of whether the singer was in crescendo or decrescendo. Perceptual and physiological implications are discussed.

  6. Offshore exposure experiments on cuttlefish indicate received sound pressure and particle motion levels associated with acoustic trauma

    PubMed Central

    Solé, Marta; Sigray, Peter; Lenoir, Marc; van der Schaar, Mike; Lalander, Emilia; André, Michel

    2017-01-01

    Recent findings on cephalopods in laboratory conditions showed that exposure to artificial noise had a direct consequence on the statocyst, sensory organs, which are responsible for their equilibrium and movements in the water column. The question remained about the contribution of the consequent near-field particle motion influence from the tank walls, to the triggering of the trauma. Offshore noise controlled exposure experiments (CEE) on common cuttlefish (Sepia officinalis), were conducted at three different depths and distances from the source and particle motion and sound pressure measurements were performed at each location. Scanning electron microscopy (SEM) revealed injuries in statocysts, which severity was quantified and found to be proportional to the distance to the transducer. These findings are the first evidence of cephalopods sensitivity to anthropogenic noise sources in their natural habitat. From the measured received power spectrum of the sweep, it was possible to determine that the animals were exposed at levels ranging from 139 to 142 dB re 1 μPa2 and from 139 to 141 dB re 1 μPa2, at 1/3 octave bands centred at 315 Hz and 400 Hz, respectively. These results could therefore be considered a coherent threshold estimation of noise levels that can trigger acoustic trauma in cephalopods. PMID:28378762

  7. Birch's law for high-pressure metals and ionic solids: Sound velocity data comparison between shock wave experiments and recent diamond anvil cell experiments

    NASA Astrophysics Data System (ADS)

    Boness, David A.; Ware, Lucas

    2017-01-01

    Sound velocity-density systematics has long been a fruitful way to take shock wave measurements on elements, alloys, oxides, rocks, and other materials, and allow reasonable extrapolation to densities found deep in the Earth. Recent detection of super-Earths has expanded interest in terrestrial planetary interiors to an even greater range of materials and pressures. Recent published diamond anvil cell (DAC) experimental measurements of sound velocities in iron and iron alloys, relevant to planetary cores, are inconsistent with each other with regard to the validity of Birch's Law, a linear relation between sound velocity and density. We examine the range of validity of Birch's Law for several shocked metallic elements, including iron, and shocked ionic solids and make comparisons to the recent DAC data.

  8. Birch's Law for high-pressure metals and ionic solids: Sound velocity data comparison between shock wave experiments and recent diamond anvil cell experiments

    NASA Astrophysics Data System (ADS)

    Boness, David; Ware, Lucas

    2015-06-01

    Sound velocity-density systematics has long been a fruitful way to take shock wave measurements on elements, alloys, oxides, rocks, and other materials, and allow reasonable extrapolation to densities found deep in the Earth. Recent detection of super-Earths has expanded interest in terrestrial planetary interiors to an even greater range of materials and pressures. Recent published DAC experimental measurements of sound velocities in iron and iron alloys, relevant to planetary cores, are inconsistent with each other with regard to the validity of Birch's Law, a linear relation between sound velocity and density. We examine the range of validity of Birch's Law for several shocked metallic elements, including iron, and shocked ionic solids and make comparisons to the recent DAC data.

  9. A novel approach for the isolation of the sound and pseudo-sound contributions from near-field pressure fluctuation measurements: analysis of the hydroacoustic and hydrodynamic perturbation in a propeller-rudder system

    NASA Astrophysics Data System (ADS)

    Felli, Mario; Grizzi, Silvano; Falchi, Massimo

    2014-01-01

    The main scope of the present work is to investigate the mechanisms underlying the hydroacoustic and hydrodynamic perturbations in a rudder operating in the wake of a free running marine propeller. The study consisted of detailed near-field pressure fluctuation measurements which were acquired on the face and back surfaces of the rudder, at different deflection angles. To this aim, a novel wavelet-filtering procedure was applied to separate and analyze distinctly the acoustic and hydrodynamic components of the recorded near-field pressure signals. The filtering procedure undertakes the separation of intermittent pressure peaks induced by the passage of eddy structures, interpreted as pseudo-sound, from homogenous background fluctuations, interpreted as sound. The use of wavelet in the filtering procedure allows to overcome the limitations of the earlier attempts based on frequency (wave number) band-pass filtering, retrieving the overall frequency content of both the acoustic and the hydrodynamic components and returning them as independent signals in the time domain. Acoustic and hydrodynamic pressure distributions were decomposed harmonically and compared to the corresponding topologies of the vorticity field, derived from earlier LDV measurements performed by Felli and Falchi (Exp Fluids 51(5):1385-1402, 2011). The study highlighted that the acoustic perturbation is mainly correlated with the unsteady load variations of the rudder and to the shear layer fluctuations of the propeller streamtube. Conversely, the dynamics of the propeller tip and hub vortices underlies the hydrodynamic perturbation.

  10. The speed of sound and derived thermodynamic properties of pure water at temperatures between (253 and 473) K and at pressures up to 400 MPa.

    PubMed

    Lin, C-W; Trusler, J P M

    2012-03-07

    The speed of sound in high-purity water has been measured in the temperature range (253 to 473) K at pressures up to 400 MPa. The experimental technique used was based on a double-path pulse-echo method with a single 5-MHz ultrasound transducer placed between two unequally spaced reflectors. The cell was calibrated in water at T = 298.15 K and p = 1 MPa against the speed of sound given by the 1995 equation-of-state formulation of the International Association for the Properties of Water and Steam (IAPWS-95) which, for that state point, has an uncertainty of 0.005%. Corrections for the effects of temperature and pressure on the path length difference are considered in detail. The estimated expanded relative uncertainty of the speed of sound determined in this work is shown to be between 0.03% and 0.04% at a confidence level of 95%. The density and isobaric specific heat capacity of water have been obtained in the temperature range (253.15 to 473.15) K at pressure up to 400 MPa by thermodynamic integration of the sound-speed data subject to initial values computed from IAPWS-95 on the isobar at p = 0.1 MPa. The speed of sound, density, and isobaric specific heat capacity were compared with IAPWS-95 with corresponding absolute relative deviations within 0.3%, 0.03%, and 1%, respectively at T ≥ 273.15 K and p ≤ 400 MPa; larger deviations, especially for heat capacity, were found at lower temperatures. The results imply that the uncertainties of properties computed from IAPWS-95 may be significantly reduced over the major part of the region investigated in this work. © 2012 American Institute of Physics

  11. Background sound pressure fluctuations (5 DB) from overhead ventilation systems increase subjective fatigue of university students during three-hour lectures.

    PubMed

    Persinger, M A; Tiller, S G; Koren, S A

    1999-04-01

    During each of four successive sessions (once per week), 21 university students attended 3-hr. lectures. During alternative weeks the fans of the room's ventilation system were either on or off. When operating, they generated an average sound pressure that varied continuously between 60 and 65 dB. The dominant frequency of this 5-dB amplitude modulation of sound pressure was within the electroencephalographic range (5 Hz to 25 Hz). At the end of each hour of the lecture for each session each student estimated on 7-point summated rating scales fatigue (none to maximum) and concentration (poor to excellent). As a group, the students reported more fatigue during lectures when the fans were operating relative to lectures when the fans were not operating. This environmental effect explained about 30% of the variance in fatigue ratings and may be sufficient to affect adversely the attention of students within these settings.

  12. Equivalent threshold sound pressure levels (ETSPL) for Sennheiser HDA 280 supra-aural audiometric earphones in the frequency range 125 Hz to 8000 Hz.

    PubMed

    Poulsen, Torben; Oakley, Sebastian

    2009-05-01

    Hearing threshold sound pressure levels were measured for the Sennheiser HDA 280 audiometric earphone. Hearing thresholds were measured for 25 normal-hearing test subjects at the 11 audiometric test frequencies from 125 Hz to 8000 Hz. Sennheiser HDA 280 is a supra-aural earphone that may be seen as a substitute for the classical Telephonics TDH 39. The results are given as the equivalent threshold sound pressure level (ETSPL) measured in an acoustic coupler specified in IEC 60318-3. The results are in good agreement with an independent investigation from PTB, Braunschweig, Germany. From acoustic laboratory measurements ETSPL values are calculated for the ear simulator specified in IEC 60318-1. Fitting of earphone and coupler is discussed. The data may be used for a future update of the RETSPL standard for supra-aural audiometric earphones, ISO 389-1.

  13. Cortical Response Variation with Different Sound Pressure Levels: A Combined Event-Related Potentials and fMRI Study

    PubMed Central

    Arrubla, Jorge; Warbrick, Tracy; Hitz, Konrad; Wyss, Christine; Boers, Frank; Shah, N. Jon

    2014-01-01

    Introduction Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) provides high spatial and temporal resolution. In this study we combined EEG and fMRI to investigate the structures involved in the processing of different sound pressure levels (SPLs). Methods EEG data were recorded simultaneously with fMRI from 16 healthy volunteers using MR compatible devices at 3 T. Tones with different SPLs were delivered to the volunteers and the N1/P2 amplitudes were included as covariates in the fMRI data analysis in order to compare the structures activated with high and low SPLs. Analysis of variance (ANOVA) and ROI analysis were also performed. Additionally, source localisation analysis was performed on the EEG data. Results The integration of averaged ERP parameters into the fMRI analysis showed an extended map of areas exhibiting covariation with the BOLD signal related to the auditory stimuli. The ANOVA and ROI analyses also revealed additional brain areas other than the primary auditory cortex (PAC) which were active with the auditory stimulation at different SPLs. The source localisation analyses showed additional sources apart from the PAC which were active with the high SPLs. Discussion The PAC and the insula play an important role in the processing of different SPLs. In the fMRI analysis, additional activation was found in the anterior cingulate cortex, opercular and orbito-frontal cortices with high SPLs. A strong response of the visual cortex was also found with the high SPLs, suggesting the presence of cross-modal effects. PMID:25279457

  14. Cortical response variation with different sound pressure levels: a combined event-related potentials and FMRI study.

    PubMed

    Neuner, Irene; Kawohl, Wolfram; Arrubla, Jorge; Warbrick, Tracy; Hitz, Konrad; Wyss, Christine; Boers, Frank; Shah, N Jon

    2014-01-01

    Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) provides high spatial and temporal resolution. In this study we combined EEG and fMRI to investigate the structures involved in the processing of different sound pressure levels (SPLs). EEG data were recorded simultaneously with fMRI from 16 healthy volunteers using MR compatible devices at 3 T. Tones with different SPLs were delivered to the volunteers and the N1/P2 amplitudes were included as covariates in the fMRI data analysis in order to compare the structures activated with high and low SPLs. Analysis of variance (ANOVA) and ROI analysis were also performed. Additionally, source localisation analysis was performed on the EEG data. The integration of averaged ERP parameters into the fMRI analysis showed an extended map of areas exhibiting covariation with the BOLD signal related to the auditory stimuli. The ANOVA and ROI analyses also revealed additional brain areas other than the primary auditory cortex (PAC) which were active with the auditory stimulation at different SPLs. The source localisation analyses showed additional sources apart from the PAC which were active with the high SPLs. The PAC and the insula play an important role in the processing of different SPLs. In the fMRI analysis, additional activation was found in the anterior cingulate cortex, opercular and orbito-frontal cortices with high SPLs. A strong response of the visual cortex was also found with the high SPLs, suggesting the presence of cross-modal effects.

  15. Abrupt laryngeal engagement during stop plosive-vowel transitions in children with repaired cleft palate and adequate velopharyngeal closure: aerodynamic and sound pressure level evidence.

    PubMed

    Zajac, David J; Milholland, Sarah

    2014-01-01

    To determine whether children with repaired cleft palate and adequate velopharyngeal closure exhibit abrupt laryngeal engagement during stop plosive-vowel transitions as compared with children without cleft palate. A prospective group design was used with convenience sampling of patients at a university craniofacial center. PARTICIPANTS were 25 children (15 boys, 10 girls) with repaired cleft palate (mean age = 10.9 years, standard deviation = 1.5 years) and 20 children (10 boys, 10 girls) without cleft palate (mean age = 10.8 years, standard deviation = 1.8 years). All children with cleft palate had adequate velopharyngeal closure as determined by aerodynamic testing. (1) Peak oral airflow was determined during the release of /t/ in the word "two" during a counting task. (2) An index of laryngeal engagement defined as the ratio of the maximum oral airflow declination to peak oral airflow was calculated during the release of /t/. (3) Sound pressure level was determined during the vowel of the word "two." Children with cleft palate exhibited significantly more negative laryngeal engagement ratios (i.e., more abrupt adduction) (P = .002) and greater sound pressure level (P = .049) than controls. There was a significant negative relationship between laryngeal engagement and sound pressure level for all children (r = -.428, P = .003). Children with repaired cleft palate and adequate velopharyngeal function appear to use a strategy of abrupt laryngeal adduction during stop plosive-vowel transitions. This strategy-perhaps learned even prior to palate surgery-may help to achieve either adequate sound pressure level and/or velopharyngeal closure.

  16. Liquid alkali metals - Equation of state and reduced-pressure, bulk-modulus, sound-velocity, and specific-heat functions

    NASA Technical Reports Server (NTRS)

    Schlosser, Herbert; Ferrante, John

    1989-01-01

    The previous work of Schlosser and Ferrante (1988) on universality in solids is extended to the study of liquid metals. As in the case of solids, to a good approximation, in the absence of phase transitions, plots of the logarithm of the reduced-pressure function H, of the reduced-isothermal-bulk-modulus function b, and of the reduced-sound-velocity function v are all linear in 1-X. Finally, it is demonstrated that ln(Cp/C/v) is also linear in 1-X, where X = (V/V/0/)exp 1/3), and V(0) is the volume at zero pressure.

  17. Liquid alkali metals - Equation of state and reduced-pressure, bulk-modulus, sound-velocity, and specific-heat functions

    NASA Technical Reports Server (NTRS)

    Schlosser, Herbert; Ferrante, John

    1989-01-01

    The previous work of Schlosser and Ferrante (1988) on universality in solids is extended to the study of liquid metals. As in the case of solids, to a good approximation, in the absence of phase transitions, plots of the logarithm of the reduced-pressure function H, of the reduced-isothermal-bulk-modulus function b, and of the reduced-sound-velocity function v are all linear in 1-X. Finally, it is demonstrated that ln(Cp/C/v) is also linear in 1-X, where X = (V/V/0/)exp 1/3), and V(0) is the volume at zero pressure.

  18. Sound Power Determination Using Sound Intensity Measurements: Applications and Extensions

    NASA Astrophysics Data System (ADS)

    Yang, Shaobo

    1995-01-01

    The determination of sound power using sound intensity measurements is one of the most important developments in acoustics since the advent of digital signal processing techniques and FFT (fast Fourier transform) techniques in 1970's. Sound power determination using sound intensity measurements is the only way to precisely determine the sound power of noise sources in operating conditions when other noise sources are operating simultaneously. Sound power determination from sound intensity measurements largely obviates the need for special purpose test facilities, such as an anechoic room or a reverberation room. The determination of sound power from sound intensity measurements has many distinct advantages over the traditional determination of the sound power from sound pressure, and it will soon become the dominant method in the determination of the sound power of noise sources in-situ. Sound intensity measurements have been successfully applied to the determination of the sound power levels of noise sources in laboratory conditions, and of small machinery noise sources. The full scale application of this new technique to industrial machinery noise sources is certainly of importance for practical purposes. This dissertation mainly describes progress made in research on the application of sound intensity measurements for the determination of the sound power of noise sources. Results concerning the sound power determination from sound intensity measurements in the following areas are discussed: sound power determination from sound intensity measurements at low frequency, error analysis of sound intensity estimates at low frequency, and sound power determination from sound intensity measurements in the presence of air flow, sound power determination from sound intensity measurements in the presence of strong background noise and some practical considerations on the application of the sound intensity technique to in-situ sound power determination.

  19. Measurements of Sound Velocity and Grüneisen Parameter in CH and MgO Shocked to Mbar Pressures

    NASA Astrophysics Data System (ADS)

    McCoy, C. A.; Gregor, M. C.; Polsin, D. N.; Boehly, T. R.; Meyerhofer, D. D.; Fratanduono, D. E.; Celliers, P. M.

    2015-11-01

    We present sound velocity measurements using an unsteady wave analysis to relate acoustic perturbations in a sample to those in a standard with known sound velocity and Grüneisen parameter. The contraction and dilation of perturbations in the shock velocities in each material provide information on the sound velocity. Experiments measured the sound velocity and Grüneisen parameter in shocked CH and MgO (periclase) relative to a quartz standard. Hugoniot measurements were also made for MgO shocked to the fluid state; a modified Us -up relation is presented. The results are compared to SESAME and LEOS tables for CH and MgO. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  20. Experimental measurement of speeds of sound in dense supercritical carbon monoxide and development of a high-pressure, high-temperature equation of state.

    PubMed

    Zaug, Joseph M; Carter, Jeffrey A; Bastea, Sorin; Armstrong, Michael R; Crowhurst, Jonathan C; Fried, Laurence E

    2013-05-09

    We report the adiabatic sound speeds for supercritical fluid carbon monoxide along two isotherms, from 0.17 to 2.13 GPa at 297 K and from 0.31 to 3.2 GPa at 600 K. The carbon monoxide was confined in a resistively heated diamond-anvil cell, and the sound speed measurements were conducted in situ using a recently reported variant of the photoacoustic light scattering effect. The measured sound speeds were then used to parametrize a single site dipolar exponential-6 intermolecular potential for carbon monoxide. PρT thermodynamic states, sound speeds, and shock Hugoniots were calculated using the newly parametrized intermolecular potential and compared to previously reported experimental results. Additionally, we generated an analytical equation of state for carbon monoxide by fitting to a grid of calculated PρT states over a range of 0.1-10 GPa and 150-2000 K. A 2% mean variation was found between computed high-pressure solid-phase densities and measured data-a surprising result for a spherical interaction potential. We further computed a rotationally dependent fluid to β-solid phase boundary; results signal the relative magnitude of short-range rotational disorder under conditions that span existing phase boundary measurements.

  1. Sound of sonoluminescence

    NASA Astrophysics Data System (ADS)

    Elze, H.-Thomas; Kodama, Takeshi; Rafelski, Johann

    1998-04-01

    We consider an air bubble in water under conditions of single-bubble sonoluminescence (SBSL) and evaluate the emitted sound field nonperturbatively for subsonic gas-liquid interface motion. Sound emission being the dominant damping mechanism, we also implement the nonperturbative sound damping in the Rayleigh-Plesset equation for the interface motion. We evaluate numerically the sound pulse emitted during bubble collapse and compare the nonperturbative and perturbative results, showing that the usual perturbative description leads to an overestimate of the maximal surface velocity and maximal sound pressure. The radius vs time relation for a full SBSL cycle remains deceptively unaffected.

  2. Evaluation of sound exposure and risk of hearing impairment in orchestral musicians.

    PubMed

    Pawlaczyk-Łuszczyńska, Małgorzata; Dudarewicz, Adam; Zamojska, Małgorzata; Sliwinska-Kowalska, Mariola

    2011-01-01

    This study aimed to assess exposure to sound and the risk of noise-induced hearing loss (NIHL) in orchestral musicians. Sound pressure level was measured in 1 opera and 3 symphony orchestras; questionnaires were filled in. On the basis of that data, the risk of NIHL was assessed according to Standard No. ISO 1999:1990. Classical orchestral musicians are usually exposed to sound at equivalent continuous A-weighted sound pressure levels of 81?90 dB (10th?90th percentiles), for 20?45 h (10th?90th percentiles) per week. Occupational exposure to such sound levels over 40 years of employment might cause hearing loss (expressed as a mean hearing threshold level at 2, 3, 4 kHz exceeding 35 dB) of up to 26%. Playing the horn, trumpet, tuba and percussion carries the highest risk (over 20%).

  3. A new developed velocity of sound measurement device for characterization of multi-component gas mixtures under elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Seibel, C.; Suedmeyer, J.; Fieback, T. M.

    2014-07-01

    Inline process control by measurement of velocity of sound of fluids is a direct and comprehensive technique [J. D. N. Cheeke and Z. Wang, "Acoustic wave gas sensors," Sens. Actuators B 59, 146-153 (1999); J. W. Grate, S. J. Martin, and R. M. White, "Acoustic wave microsensors," Anal. Chem. 65, 1868 (1993)]. Depending on the varying conditions of measuring fluid(s), temperatures and pressures, it is a challenging task to find the best possible acoustic setup. Taking this background into account, a velocity of sound measurement device for temperatures up to 475 K and pressures up to 24 MPa was designed and assembled that is to be used for testing different resonator types. Two bulk acoustic wave resonators out of the commonly used lead zirconatetitanate compound (PZT) were tested at different test fluids under temperatures up to 423.15 K and pressures up to 24 MPa [S. Gebhardt, L. Seffner, F. Schlenkirch, and A. Schönecker, "PZT thick films for sensor and actuator applications," J. Eur. Ceram. Soc. 27, 4177-4180 (2007)]. Initially the pure gases methane, ethane, carbon dioxide, nitrogen, and helium were measured, followed by multi-component gas mixtures. Beside methane-based binary and ternary gas mixtures, a quaternary gas mixture comprising methane, ethane, carbon dioxide, and helium was analyzed. Results for all measurement fluids in a broad temperature and pressure range show a relative deviation to theoretical values derived from GERG-2008 smaller than 0.5%.

  4. A new developed velocity of sound measurement device for characterization of multi-component gas mixtures under elevated temperatures and pressures.

    PubMed

    Seibel, C; Suedmeyer, J; Fieback, T M

    2014-07-01

    Inline process control by measurement of velocity of sound of fluids is a direct and comprehensive technique [J. D. N. Cheeke and Z. Wang, "Acoustic wave gas sensors," Sens. Actuators B 59, 146-153 (1999); J. W. Grate, S. J. Martin, and R. M. White, "Acoustic wave microsensors," Anal. Chem. 65, 1868 (1993)]. Depending on the varying conditions of measuring fluid(s), temperatures and pressures, it is a challenging task to find the best possible acoustic setup. Taking this background into account, a velocity of sound measurement device for temperatures up to 475 K and pressures up to 24 MPa was designed and assembled that is to be used for testing different resonator types. Two bulk acoustic wave resonators out of the commonly used lead zirconatetitanate compound (PZT) were tested at different test fluids under temperatures up to 423.15 K and pressures up to 24 MPa [S. Gebhardt, L. Seffner, F. Schlenkirch, and A. Schönecker, "PZT thick films for sensor and actuator applications," J. Eur. Ceram. Soc. 27, 4177-4180 (2007)]. Initially the pure gases methane, ethane, carbon dioxide, nitrogen, and helium were measured, followed by multi-component gas mixtures. Beside methane-based binary and ternary gas mixtures, a quaternary gas mixture comprising methane, ethane, carbon dioxide, and helium was analyzed. Results for all measurement fluids in a broad temperature and pressure range show a relative deviation to theoretical values derived from GERG-2008 smaller than 0.5%.

  5. In-situ Ultrasonic Sound Velocity Measurements of Fe and Fe-Light Element Alloying Liquids at High Pressures with Implications to Planetary Cores

    NASA Astrophysics Data System (ADS)

    Jing, Z.; Wang, Y.; Yu, T.; Sakamaki, T.; Kono, Y.; Park, C.

    2012-12-01

    Liquid Fe-light element alloys are likely present in the Earth's outer core and the cores of other terrestrial planets and moons including Mercury, Mars, Earth's Moon, Ganymede, and Io, as suggested by geophysical and geochemical observations. In order to determine the abundances of light elements and their effects on the structure, dynamics, and evolution of planetary cores, it is crucial to determine the equation of state for Fe-X (X=S, Si, C, O, etc.) liquids under core conditions. However, equations of state for Fe-rich liquids are poorly constrained at planetary core pressures due to the scarcity of density data and the absence of sound velocity data for these liquids at high pressures. At GSECARS, we have developed techniques to directly measure the ultrasonic sound velocities of Fe-rich liquids at high pressures using both a Kawai-type multi-anvil apparatus and a Paris-Edinburgh cell. The sound velocity was determined by measuring the travel time difference between the sample echo and the buffer rod echo using a waveform generator and a digital oscilloscope and by measuring the sample thickness using X-ray radiographic images. X-ray diffraction was also used to determine the pressure of the experiments and to confirm the melting of the samples. Using this technique, we have successfully obtained sound velocities of three Fe-S liquid compositions (Fe-10wt%S, Fe-20wt%S, and Fe-27wt%S), two Fe-Si liquid compositions (Fe-17wt%Si and Fe-25wt%Si), and pure Fe liquid at high pressure and temperature conditions up to 8 GPa and 2073 K. Results show significant differences between Fe-S and Fe-Si liquids: (1) The velocity of liquid Fe decreases with increasing sulfur content, but increases with silicon content; (2) Velocity is nearly independent of temperature for Fe-S liquids, but decreases with increasing temperature for Fe-Si liquids. These data can provide tighter constraints on equations of state of Fe-light element liquids and adiabatic temperature gradients in

  6. Light aircraft sound transmission study

    NASA Technical Reports Server (NTRS)

    Heitman, K.; Bernhard, R. J.

    1983-01-01

    The plausibility of using the two microphone sound intensity technique to study noise transmission into light aircraft was investigated. In addition, a simple model to predict the interior sound pressure level of the cabin was constructed.

  7. Hemodynamic effects of short-term noise exposure--comparison of steady state and intermittent noise at several sound pressure levels.

    PubMed

    Sawada, Y

    1993-09-01

    The purpose of the present study was to investigate the extent of blood pressure elevation during noise exposure, to elucidate the underlying hemodynamic mechanisms and to assess baroreceptor cardiac reflex sensitivity in connection with blood pressure elevation. Twenty-two young normotensive males participated in the experiment and underwent six noise exposure conditions of 20 min each: steady state and intermittent pink noises of 80 dB (sound pressure level (SPL)), 90 dB (SPL) and 100 dB (SPL). The results indicate that elevations in mean arterial pressure, as well as diastolic and systolic blood pressure, were significant or almost significant in the intermittent 100 dB (SPL) and 90 dB (SPL) conditions. Habituation occurred particularly with the steady state noises. In at least the intermittent 100 dB (SPL) condition, an increase in peripheral vascular resistance was the underlying hemodynamic mechanism of blood pressure elevation. Decreases in cardiac output and stroke volume were also associated with the peripheral vasoconstriction. Baroreceptor reflex sensitivity was maintained near the baseline level for all of the noise exposure conditions. Therefore, reflex sensitivity may not have been suppressed even in the intermittent 100 dB (SPL) condition during which blood pressure elevations occurred.

  8. Speed-of-Sound Measurements in (Argon + Carbon Dioxide) over the Temperature Range from (275 to 500) K at Pressures up to 8 MPa

    PubMed Central

    Wegge, Robin; McLinden, Mark O.; Perkins, Richard A.; Richter, Markus; Span, Roland

    2016-01-01

    The speed of sound of two (argon + carbon dioxide) mixtures was measured over the temperature range from (275 to 500) K with pressures up to 8 MPa utilizing a spherical acoustic resonator. The compositions of the gravimetrically prepared mixtures were (0.50104 and 0.74981) mole fraction carbon dioxide. The vibrational relaxation of pure carbon dioxide led to high sound absorption, which significantly impeded the sound-speed measurements on carbon dioxide and its mixtures; pre-condensation may have also affected the results for some measurements near the dew line. Thus, in contrast to the standard operating procedure for speed-of-sound measurements with a spherical resonator, non-radial resonances at lower frequencies were taken into account. Still, the data show a comparatively large scatter, and the usual repeatability of this general type of instrument could not be realized with the present measurements. Nonetheless, the average relative combined expanded uncertainty (k = 2) in speed of sound ranged from (0.042 to 0.056)% for both mixtures, with individual state-point uncertainties increasing to 0.1%. These uncertainties are adequate for our intended purpose of evaluating thermodynamic models. The results are compared to a Helmholtz energy equation of state for carbon capture and storage applications; relative deviations of (−0.64 to 0.08)% for the (0.49896 argon + 0.50104 carbon dioxide) mixture, and of (−1.52 to 0.77)% for the (0.25019 argon + 0.74981 carbon dioxide) mixture were observed. PMID:27458321

  9. Speed-of-Sound Measurements in (Argon + Carbon Dioxide) over the Temperature Range from (275 to 500) K at Pressures up to 8 MPa.

    PubMed

    Wegge, Robin; McLinden, Mark O; Perkins, Richard A; Richter, Markus; Span, Roland

    2016-08-01

    The speed of sound of two (argon + carbon dioxide) mixtures was measured over the temperature range from (275 to 500) K with pressures up to 8 MPa utilizing a spherical acoustic resonator. The compositions of the gravimetrically prepared mixtures were (0.50104 and 0.74981) mole fraction carbon dioxide. The vibrational relaxation of pure carbon dioxide led to high sound absorption, which significantly impeded the sound-speed measurements on carbon dioxide and its mixtures; pre-condensation may have also affected the results for some measurements near the dew line. Thus, in contrast to the standard operating procedure for speed-of-sound measurements with a spherical resonator, non-radial resonances at lower frequencies were taken into account. Still, the data show a comparatively large scatter, and the usual repeatability of this general type of instrument could not be realized with the present measurements. Nonetheless, the average relative combined expanded uncertainty (k = 2) in speed of sound ranged from (0.042 to 0.056)% for both mixtures, with individual state-point uncertainties increasing to 0.1%. These uncertainties are adequate for our intended purpose of evaluating thermodynamic models. The results are compared to a Helmholtz energy equation of state for carbon capture and storage applications; relative deviations of (-0.64 to 0.08)% for the (0.49896 argon + 0.50104 carbon dioxide) mixture, and of (-1.52 to 0.77)% for the (0.25019 argon + 0.74981 carbon dioxide) mixture were observed.

  10. Assessment and evaluation of noise controls on roof bolting equipment and a method for predicting sound pressure levels in underground coal mining

    NASA Astrophysics Data System (ADS)

    Matetic, Rudy J.

    Over-exposure to noise remains a widespread and serious health hazard in the U.S. mining industries despite 25 years of regulation. Every day, 80% of the nation's miners go to work in an environment where the time weighted average (TWA) noise level exceeds 85 dBA and more than 25% of the miners are exposed to a TWA noise level that exceeds 90 dBA, the permissible exposure limit (PEL). Additionally, MSHA coal noise sample data collected from 2000 to 2002 show that 65% of the equipment whose operators exceeded 100% noise dosage comprise only seven different types of machines; auger miners, bulldozers, continuous miners, front end loaders, roof bolters, shuttle cars (electric), and trucks. In addition, the MSHA data indicate that the roof bolter is third among all the equipment and second among equipment in underground coal whose operators exceed 100% dosage. A research program was implemented to: (1) determine, characterize and to measure sound power levels radiated by a roof bolting machine during differing drilling configurations (thrust, rotational speed, penetration rate, etc.) and utilizing differing types of drilling methods in high compressive strength rock media (>20,000 psi). The research approach characterized the sound power level results from laboratory testing and provided the mining industry with empirical data relative to utilizing differing noise control technologies (drilling configurations and types of drilling methods) in reducing sound power level emissions on a roof bolting machine; (2) distinguish and correlate the empirical data into one, statistically valid, equation, in which, provided the mining industry with a tool to predict overall sound power levels of a roof bolting machine given any type of drilling configuration and drilling method utilized in industry; (3) provided the mining industry with several approaches to predict or determine sound pressure levels in an underground coal mine utilizing laboratory test results from a roof bolting

  11. Increases in plasma 25(OH)D levels are related to improvements in body composition and blood pressure in middle-aged subjects after a weight loss intervention: Longitudinal study.

    PubMed

    Ibero-Baraibar, Idoia; Navas-Carretero, Santiago; Abete, Itziar; Martinez, J A; Zulet, M A

    2015-10-01

    The aim of this study is to further clarify the role of plasma 25(OH)D concentration after a weight-lowering nutritional intervention on body composition, blood pressure and inflammatory biomarkers in overweight/obese middle-aged subjects. This longitudinal research encompassed a total of 50 subjects [57.26 (5.24) year], who were under a 15% energy restricted diet for 4 weeks. Anthropometric and body composition variables, blood routine, inflammatory markers as well as 25(OH)D were analysed. Circulating 25(OH)D levels [12.13(±17.61%)] increased while anthropometric, body composition, routine blood markers as well as the concentration of TNF-α, C-reactive protein and Lp-PLA2 were significantly reduced after the intervention. Multiple linear regression analyses evidenced that Δ25(OH)D increase was linked to the decrease in weight, adiposity, SBP and IL-6 levels. Moreover, a relationship was found between Δ25(OH)D, Δfat mass (r = -0.405; p = 0.007), ΔSBP (r = -0.355; p = 0.021) and ΔIL-6 (r = -0.386; p = 0.014). On the other hand, a higher increase in 25(OH)D was accompanied by reductions in weight, BMI, SBP, IL-6 and an increase in bone mineral concentration (p < 0.05). Interestingly, higher levels of 25(OH)D at the endpoint, showed a significantly higher decrease in weight, BMI and total fat mass. The increase in plasma 25(OH)D level is linked with the decrease in SBP and adiposity in middle-aged subjects after a weight-loss intervention. Therefore, 25(OH)D assessment is a potential marker to be accounted in metabolic measures related to blood pressure, adiposity and inflammation in obesity management. www.clinicaltrials.gov (NCT01596309). Copyright © 2014 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  12. Differences and intersubject variability of loudness discomfort levels measured in sound pressure level and hearing level for TDH-50P and ER-3A earphones.

    PubMed

    Valente, M; Potts, L G; Valente, M

    1997-02-01

    Loudness discomfort levels (LDLs) were measured in dB HL and SPL at discrete frequencies between 500 to 4000 Hz on 31 hearing-impaired ears using TDH-50P and ER-3A earphones. The results revealed no significant differences in the measured sound pressure level (SPL) between the two earphones at all test frequencies. However, with dB HL measurements, statistically significant differences were revealed at 1500 and 4000 Hz between earphone conditions. The results also revealed large intersubject differences in the measured LDL (HL and SPL) for both earphones. The results of this study highlight the difficulty in accurately predicting individual performance from averaged group data.

  13. Comparison of Sound Pressure Distribution Determined by Numerical Analysis and Scaled-Up Experiment for Small Ultrasonic Probe with Lens

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Takenobu; Matsumoto, Sayuri; Naitou, Fumitaka; Takahashi, Mari; Endoh, Nobuyuki

    2009-07-01

    Ultrasonic medical equipment is used in not only diagnosis but also therapy such as that for treating hyperthermia. Many researchers are also studying high-frequency ultrasonic imaging systems with interluminal or catheter transducers. In both applications, an acoustic lens might improve the characteristics of ultrasonic medical probes. In this paper, a small acoustic lens for an ultrasonic catheter-type probe is described. The conventional three-dimensional finite-difference time-domain (3D FDTD) with orthogonal coordinates requires a large memory and a long calculation time to estimate the characteristics of the lens. To overcome these disadvantages, a simple two-dimensional (2D) FDTD calculation based on symmetry is proposed in this paper. A virtual spherical sound source whose amplitude distribution is equal to that of the sound propagation field of an actual sound source is also used to simplify the calculation. A numerical model of the lens with a lens holder is constructed. The experimental results agree well with the calculated results with the lens holder.

  14. Speed of Sound in Aqueous Solutions at sub-GPa Pressures: a New Experiment to Unveil the Properties of Extra-Terrestrial Oceans

    NASA Astrophysics Data System (ADS)

    Bollengier, O.; Brown, J. M.; Vance, S.; Shaw, G. H.

    2015-12-01

    Geophysical data from the Galileo and Cassini-Huygens missions are consistent with the presence of aqueous subsurface oceans in Ganymede, Callisto and Titan, the largest icy satellites of the solar system. To understand the history and present state of these moons, the next generation of evolution models will require an accurate description of the properties of these liquid layers to predict the phase boundaries, heat transports and chemical exchanges within them. Sound speed measurements in pressure and temperature allow for the reconstruction of the Gibbs free energy surface of a phase, which in turn gives access to the desired properties (chemical potential, density, heat capacity...). However, such data are still scarce for aqueous solutions bearing Na+, Mg2+, Cl- and SO42- ions (major ions expected in extra-terrestrial oceans) at the high pressures and low temperatures expected for water inside these moons (up to 1.5 GPa for Ganymede, down to freezing temperatures). For pure water, IAPWS accuracy for sound speeds is given to 0.3% above 0.4 GPa. MgSO4aqueous solutions have been explored to 0.7 GPa with a precision limited to about 0.5%. Most other aqueous solutions bearing any combination of these four ions have not been explored at all above a few hundreds MPa. To acquire new high-precision sound speeds in aqueous solutions of various compositions, we set up a new experimental system working in the 0 - 0.7 GPa pressure range and 240 - 350 K temperature range. The device consists in an oil-pressurized steel vessel enclosing a titanium alloy rod supporting the sample and a sealing bellows. A transducer at the top end of the titanium rod generates ultrasonic waves and collects the series of subsequent reflections. Preliminary tests with pure water illustrate a precision of 0.02% and an accuracy within 0.1% of IAPWS on our whole pressure range. Revision of the properties of pure water and H2O-MgSO4 solutions up to 0.7 GPa along with the first data in the H2O-MgCl2

  15. A Preliminary Investigation of the Air-Bone Gap: Changes in Intracochlear Sound Pressure With Air- and Bone-conducted Stimuli After Cochlear Implantation.

    PubMed

    Banakis Hartl, Renee M; Mattingly, Jameson K; Greene, Nathaniel T; Jenkins, Herman A; Cass, Stephen P; Tollin, Daniel J

    2016-10-01

    A cochlear implant electrode within the cochlea contributes to the air-bone gap (ABG) component of postoperative changes in residual hearing after electrode insertion. Preservation of residual hearing after cochlear implantation has gained importance as simultaneous electric-acoustic stimulation allows for improved speech outcomes. Postoperative loss of residual hearing has previously been attributed to sensorineural changes; however, presence of increased postoperative ABG remains unexplained and could result in part from altered cochlear mechanics. Here, we sought to investigate changes to these mechanics via intracochlear pressure measurements before and after electrode implantation to quantify the contribution to postoperative ABG. Human cadaveric heads were implanted with titanium fixtures for bone conduction transducers. Velocities of stapes capitulum and cochlear promontory between the two windows were measured using single-axis laser Doppler vibrometry and fiber-optic sensors measured intracochlear pressures in scala vestibuli and tympani for air- and bone-conducted stimuli before and after cochlear implant electrode insertion through the round window. Intracochlear pressures revealed only slightly reduced responses to air-conducted stimuli consistent with previous literature. No significant changes were noted to bone-conducted stimuli after implantation. Velocities of the stapes capitulum and the cochlear promontory to both stimuli were stable after electrode placement. Presence of a cochlear implant electrode causes alterations in intracochlear sound pressure levels to air, but not bone, conducted stimuli and helps to explain changes in residual hearing noted clinically. These results suggest the possibility of a cochlear conductive component to postoperative changes in hearing sensitivity.

  16. USAF bioenvironmental noise data handbook. Volume 168: MB-3 tester, pressurized cabin leakage, aircraft

    NASA Astrophysics Data System (ADS)

    Rau, T. H.

    1982-06-01

    The MB-3 Tester is an electric motor-driven cabin leakage tester designed to furnish pressurized air to the aircraft at controlled pressures and temperatures during ground pressurization of aircraft cockpits and pressurized compartments. This report provides measured data defining the bioacoustic environments produced by this unit operating at a normal rated/load condition. Near-field data are reported for 37 locations in a wide variety of physical and psychoacoustic measures: overall and band sound pressure levels, C-weighted and A-weighted sound levels, preferred speech interference level, perceived noise level, and limiting times for total daily exposure of personnel with and without standard Air Force ear protectors.

  17. Pressure Sounding of the Middle Atmosphere from ATMOS Solar Occultation Measurements of Atmospheric CO(sub 2) Absorption Lines

    NASA Technical Reports Server (NTRS)

    Abrams, M.; Gunson, M.; Lowes, L.; Rinsland, C.; Zander, R.

    1994-01-01

    A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(sub 2) lines with temperature-insensitive intensities. Tangent pressures are determined with a spectroscopic precision of 1-3%, corresponding to a tangent point height precision, depending on the scale height, of 70-210 meters.

  18. Sound Symbolism.

    ERIC Educational Resources Information Center

    Hinton, Leanne, Ed.; And Others

    Sound symbolism is the study of the relationship between the sound of an utterance and its meaning. In this interdisciplinary collection of new studies, 24 leading scholars discuss the role of sound symbolism in a theory of language. Contributions and authors include the following: "Sound-Symbolic Processes" (Leanne Hinton, Johanna…

  19. Sound Symbolism.

    ERIC Educational Resources Information Center

    Hinton, Leanne, Ed.; And Others

    Sound symbolism is the study of the relationship between the sound of an utterance and its meaning. In this interdisciplinary collection of new studies, 24 leading scholars discuss the role of sound symbolism in a theory of language. Contributions and authors include the following: "Sound-Symbolic Processes" (Leanne Hinton, Johanna…

  20. Pressure sounding of the middle atmosphere from ATMOS solar occultation measurements of atmospheric CO(2) absorption lines.

    PubMed

    Abrams, M C; Gunson, M R; Lowes, L L; Rinsland, C P; Zander, R

    1996-06-01

    A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier-transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(2) lines with temperature-insensitive strengths by measuring the slant-column CO(2) amount and by adjusting the viewing geometry until the calculated column matches the observed column. Tangent pressures are determined with a spectroscopic precision of l%-3%, corresponding to a tangent-point height precision of 70-210 m. The total uncertainty is limited primarily by the quality of the spectra and ranges between 4% and 6% (280-420 m) for spectra with signal-to-noise ratios of 300:1 and between 4% and 10% for spectra with signal-to-noise ratios of 100:1. The retrieval of atmospheric pressure increases the accuracy of the retrieved-gas concentrations by minimizing the effect of systematic errors introduced by climatological pressure data, ephemeris parameters, and the uncertainties in instrumental pointing.

  1. Pressure plate analysis of toe-heel and medio-lateral hoof balance at the walk and trot in sound sport horses.

    PubMed

    Oosterlinck, M; Hardeman, L C; van der Meij, B R; Veraa, S; van der Kolk, J H; Wijnberg, I D; Pille, F; Back, W

    2013-12-01

    Empirically, equine distal limb lameness is often linked to hoof imbalance. To objectively quantify dynamic toe-heel and medio-lateral hoof balance of the vertical ground reaction force in sound sport horses, seven Royal Dutch Sport Horses were led at the walk and trot over a dynamically calibrated pressure plate. Forelimb hoof prints were divided into a toe and heel region and a medial and lateral zone. Toe-heel and medio-lateral hoof balance of the vertical ground reaction force were calculated throughout the stance. Toe-heel balance was highly symmetrical between contralateral limbs at both gaits. At the walk, medio-lateral balance of both forelimbs presented higher loading in the lateral part of the hoof throughout the stance. However, at the trot, left medio-lateral balance presented higher loading of the medial part of the hoof at impact, whereas the right limb showed higher loading of the lateral part of the hoof in all horses, and both limbs presented increased lateral loading at the end of the stance. This study provides objective data for toe-heel and medio-lateral hoof balance in sound sport horses.

  2. A simple electrical lumped-element model simulates intra-cochlear sound pressures and cochlear impedance below 2 kHz.

    PubMed

    Marquardt, Torsten; Hensel, Johannes

    2013-11-01

    Low-frequency sounds displace large parts of the basilar membrane (BM) and can have a modulating and possibly disturbing effect on hearing at other frequencies. A better understanding of the transfer of such sounds onto the BM is therefore desirable. Lumped-element models have previously been employed to determine the low-frequency acoustic properties of the cochlea. Although helpful in illustrating schematically the role of the helicotrema, BM compliance, and the round window on low-frequency hearing, these models, when applied quantitatively, have not been able to explain experimental data in detail. Building on these models, an extended electrical analog requires just 13 lumped elements to capture, in surprising detail, the physiologically determined frequency-dependence of intra-cochlear pressure and cochlear impedance between 10 Hz and 2 kHz. The model's verification is based on data from cat, guinea pig, and humans, who differ principally in their low-frequency cochlear acoustics. The modeling data suggest that damping within the helicotrema plays a less prominent role than previously assumed. A resonance feature, which is often observed experimentally near 150 Hz in these animals and near 50 Hz in humans, is presumably a phenomenon local to the apex and not the result of a standing wave between stapes and helicotrema.

  3. A model for the pressure excitation spectrum and acoustic impedance of sound absorbers in the presence of grazing flow.

    NASA Technical Reports Server (NTRS)

    Rice, E. J.

    1973-01-01

    A unification of the theory of the nonlinear acoustic resistance of Helmholtz resonators including grazing flow is presented. The nonlinear resistance due to grazing flow is considered to be caused by an exciting pressure spectrum produced by the interaction of the grazing flow and the jets flowing from the resonator orifices. With this exciting pressure spectrum the resonator can be treated in the same manner as a resonator without grazing flow but with an exciting acoustic spectrum. One of the important implications of this model is that a multiple-degree-of-freedom resonator can be analyzed with grazing flow. Using the grazing flow pressure spectrum, the nonlinear acoustic resistance can be properly distributed among the several elements of the resonator.

  4. Equivalent threshold sound pressure levels for Sennheiser HDA 200 earphone and Etymotic Research ER-2 insert earphone in the frequency range 125 Hz to 16 kHz.

    PubMed

    Han, L A; Poulsen, T

    1998-01-01

    Equivalent Threshold Sound Pressure Levels (ETSPLs) have been determined for the Sennheiser HDA 200 earphone and the Etymotic Research ER-2 insert earphone. Thirty-one young normal-hearing test subjects participated and the thresholds were determined for all recommended frequencies in the frequency range 125 Hz to 16 kHz. The results for the HDA 200 earphone are generally in very good agreement with the results from two other investigations which are available at present. Only at 6 kHz is a 9 dB deviation found and at 8 kHz a 6 dB deviation is found between the three investigations. For ER-2 it has not been possible to find other ETSPL determinations in the literature.

  5. The Role of Compression and Traveling Wave Pressures in the Transmission of Sound Out of the Gerbil Cochlea

    NASA Astrophysics Data System (ADS)

    Dong, Wei; Olson, Elizabeth S.

    2009-02-01

    Cochlear emissions provide a noninvasive probe of cochlear mechanics, but their utility is hindered by incomplete understanding of their relationship to intracochlear activity. In particular, recent work has uncovered a question about the mode by which emissions travel out of the cochlea - whether they emerge via a "fast" compression pressure or a "slow" traveling-wave pressure. We further probed this question with simultaneous measurements of intracochlear distortion products (DPs) at two well-separated locations and DP oto-acoustic emissions (DPOAEs). In the broad frequency range of the local best frequency (BF), the DP responses demonstrate the now well-known forward-traveling-wave character. However, at frequencies substantially lower than the BF, comparisons of both DPOAEs to DPs and of DPs at two locations support a reverse-traveling-wave. Finally, a compression pressure DP was observed when stimulating at high levels (90 dB) with frequencies that were well above the BF. Therefore, the compression / reverse-traveling-wave question appears to be a quantitative question of the relative size of these different pressure modes. In previous and present results we find that the reverse-traveling-wave mode can be dominant both within the cochlea and in the production of DPOAEs.

  6. Characterization of the Ignition Over-Pressure/Sound Suppression Water in the Space Launch System Mobile Launcher Using Volume of Fluid Modeling

    NASA Technical Reports Server (NTRS)

    West, Jeff

    2015-01-01

    The Space Launch System (SLS) Vehicle consists of a Core Stage with four RS-25 engines and two Solid Rocket Boosters (SRBs). This vehicle is launched from the Launchpad using a Mobile Launcher (ML) which supports the SLS vehicle until its liftoff from the ML under its own power. The combination of the four RS-25 engines and two SRBs generate a significant Ignition Over-Pressure (IOP) and Acoustic Sound environment. One of the mitigations of these environments is the Ignition Over-Pressure/Sound Suppression (IOP/SS) subsystem installed on the ML. This system consists of six water nozzles located parallel to and 24 inches downstream of each SRB nozzle exit plane as well as 16 water nozzles located parallel to and 53 inches downstream of the RS-25 nozzle exit plane. During launch of the SLS vehicle, water is ejected through each water nozzle to reduce the intensity of the transient pressure environment imposed upon the SLS vehicle. While required for the mitigation of the transient pressure environment on the SLS vehicle, the IOP/SS subsystem interacts (possibly adversely) with other systems located on the Launch Pad. One of the other systems that the IOP/SS water is anticipated to interact with is the Hydrogen Burn-Off Igniter System (HBOI). The HBOI system's purpose is to ignite the unburned hydrogen/air mixture that develops in and around the nozzle of the RS-25 engines during engine start. Due to the close proximity of the water system to the HBOI system, the presence of the IOP/SS may degrade the effectiveness of the HBOI system. Another system that the IOP/SS water may interact with adversely is the RS-25 engine nozzles and the SRB nozzles. The adverse interaction anticipated is the wetting, to a significant degree, of the RS-25 nozzles resulting in substantial weight of ice forming and water present to a significant degree upstream of the SRB nozzle exit plane inside the nozzle itself, posing significant additional blockage of the effluent that exits the nozzle

  7. Effects of Increasing Sound Pressure Level on Lip and Jaw Movement Parameters and Consistency in Young Adults

    PubMed Central

    Huber, Jessica E.; Chandrasekaran, Bharath

    2012-01-01

    Purpose Examination of movement parameters and consistency has been used to infer underlying neural control of movement. However, there has been no systematic investigation of whether the way individuals are asked (or cued) to increase loudness alters articulation. The aim of the current study was to examine whether different cues to elicit louder speech induce different lip and jaw movement parameters or consistency. Methods Thirty healthy young adults produced two sentences 1) at comfortable loudness, 2) while targeting 10 dB SPL above comfortable loudness on a sound level meter, 3) at twice their perceived comfortable loudness, and 4) while multi-talker noise was played in the background. Lip and jaw kinematics and acoustic measurements were made. Results Each of the loud conditions resulted in a similar amount of SPL increase, about 10 dB. Speech rate was slower in the background noise condition. Changes to movement parameters and consistency (relative to comfortable) were different in the targeting condition as compared to the other loud conditions. Conclusions The cues elicited different task demands, and therefore, different movement patterns were utilized by the speakers to achieve the target of increased loudness. Based on these results, cueing should be considered when eliciting increased vocal loudness in both clinical and research situations. PMID:17197502

  8. Supersonic naval missile sounds over San Nicolas Island

    NASA Astrophysics Data System (ADS)

    Greene, Charles R.; Norman, Robert G.; Holst, Meike; Malme, Charles I.

    2003-10-01

    Vandals and other missiles are launched occasionally from San Nicolas Island, CA, during Naval exercises and tests. Pinnipeds on the island beaches are exposed to the flight sounds, some of which are sonic booms from directly overhead. Environmental concerns led the Navy to support acoustic studies of the missile sounds at the beaches. The results show flat-weighted sound pressures from Vandals as high as 150 dB re: 20 μPa(peak) [140 dB re: 20 μPa(rms)] at a near-vertical distance of 400 m. Other flat-weighted pressures from Vandals were as low as 107 dB re: 20 μPa(peak) [95 dB re: 20 μPa(rms)] at a beach 3.9 km horizontally behind the launcher. Pulse durations and sound exposure levels were also measured. One-third octave band sound exposure levels were measured. All parameters (except one-third octave band levels) were also measured with A weighting. Other missiles measured include Tomahawk cruise missiles, Rolling Airframe Missile, Advanced Gun System, Terrier, and the Supersonic Sea-Skimming Target. [Work supported by U.S. Navy.

  9. A preliminary investigation of the air-bone gap: Changes in intracochlear sound pressure with air- and bone-conducted stimuli after cochlear implantation

    PubMed Central

    Banakis Hartl, Renee M.; Mattingly, Jameson K.; Greene, Nathaniel T.; Jenkins, Herman A.; Cass, Stephen P.; Tollin, Daniel J.

    2016-01-01

    Hypothesis A cochlear implant electrode within the cochlea contributes to the air-bone gap (ABG) component of postoperative changes in residual hearing after electrode insertion. Background Preservation of residual hearing after cochlear implantation has gained importance as simultaneous electric-acoustic stimulation allows for improved speech outcomes. Postoperative loss of residual hearing has previously been attributed to sensorineural changes; however, presence of increased postoperative air-bone gap remains unexplained and could result in part from altered cochlear mechanics. Here, we sought to investigate changes to these mechanics via intracochlear pressure measurements before and after electrode implantation to quantify the contribution to postoperative air-bone gap. Methods Human cadaveric heads were implanted with titanium fixtures for bone conduction transducers. Velocities of stapes capitulum and cochlear promontory between the two windows were measured using single-axis laser Doppler vibrometry and fiber-optic sensors measured intracochlear pressures in scala vestibuli and tympani for air- and bone-conducted stimuli before and after cochlear implant electrode insertion through the round window. Results Intracochlear pressures revealed only slightly reduced responses to air-conducted stimuli consistent with prior literature. No significant changes were noted to bone-conducted stimuli after implantation. Velocities of the stapes capitulum and the cochlear promontory to both stimuli were stable following electrode placement. Conclusion Presence of a cochlear implant electrode causes alterations in intracochlear sound pressure levels to air, but not bone, conducted stimuli and helps to explain changes in residual hearing noted clinically. These results suggest the possibility of a cochlear conductive component to postoperative changes in hearing sensitivity. PMID:27579835

  10. A normal-mode formula for the derivative of a waveguide pressure field with respect to an arbitrary three-dimensional sound speed perturbation

    NASA Astrophysics Data System (ADS)

    Thode, Aaron

    2003-10-01

    Semi-analytic expressions are derived for the first order derivative of a pressure field in a laterally homogeneous depth waveguide, with respect to an arbitrary three-dimensional refractive index perturbation in either the water column or ocean bottom. These expressions for the environmental derivative, derived using an adjoint method, require a three-dimensional spatial correlation between two Greens functions, weighted by an environmental parameter basis function, with the Greens functions expressed in terms of normal modes. When a particular set of orthogonal spatial basis functions is chosen, the three-dimensional spatial integral can be converted into a set of one-dimensional integrations over depth and azimuth. The use of the orthogonal basis permits environmental derivatives to be computed for any arbitrary sound-speed perturbation. To illustrate the formulas, a sensitivity study is presented that explores the impact of three-dimensional plane wave and cylindrical perturbations on the environmental derivative. Under certain circumstances it is found that perturbation components outside the vertical plane connecting the source and receiver have non-negligible effects on the pressure derivative. Potential applications of these formulas include benchmarking three-dimensional propagation codes, computing Cramer-Rao bounds for three-dimensional environmental parameter estimates, and potentially inverting for small three-dimensional refractive index distributions.

  11. Abdominal sounds

    MedlinePlus

    ... may be a sign of early bowel obstruction. Causes Most of the sounds you hear in your stomach and intestines are ... a list of more serious conditions that can cause abnormal bowel sounds. Hyperactive, hypoactive, or missing bowel sounds may be ...

  12. Wind turbine sound power measurements.

    PubMed

    Keith, Stephen E; Feder, Katya; Voicescu, Sonia A; Soukhovtsev, Victor; Denning, Allison; Tsang, Jason; Broner, Norm; Richarz, Werner; van den Berg, Frits

    2016-03-01

    This paper provides experimental validation of the sound power level data obtained from manufacturers for the ten wind turbine models examined in Health Canada's Community Noise and Health Study (CNHS). Within measurement uncertainty, the wind turbine sound power levels measured using IEC 61400-11 [(2002). (International Electrotechnical Commission, Geneva)] were consistent with the sound power level data provided by manufacturers. Based on measurements, the sound power level data were also extended to 16 Hz for calculation of C-weighted levels. The C-weighted levels were 11.5 dB higher than the A-weighted levels (standard deviation 1.7 dB). The simple relationship between A- and C- weighted levels suggests that there is unlikely to be any statistically significant difference between analysis based on either C- or A-weighted data.

  13. Thermoelastic properties of liquid Fe-C revealed by sound velocity and density measurements at high pressure

    NASA Astrophysics Data System (ADS)

    Shimoyama, Yuta; Terasaki, Hidenori; Urakawa, Satoru; Takubo, Yusaku; Kuwabara, Soma; Kishimoto, Shunpachi; Watanuki, Tetsu; Machida, Akihiko; Katayama, Yoshinori; Kondo, Tadashi

    2016-11-01

    Carbon is one of the possible light elements in the cores of the terrestrial planets. The P wave velocity (VP) and density (ρ) are important factors for estimating the chemical composition and physical properties of the core. We simultaneously measured the VP and ρ of Fe-3.5 wt % C up to 3.4 GPa and 1850 K by using ultrasonic pulse-echo method and X-ray absorption methods. The VP of liquid Fe-3.5 wt % C decreased linearly with increasing temperature at constant pressure. The addition of carbon decreased the VP of liquid Fe by about 2% at 3 GPa and 1700 K and decreased the Fe density by about 2% at 2 GPa and 1700 K. The bulk modulus of liquid Fe-C and its pressure (P) and temperature (T) effects were precisely determined from directly measured ρ and VP data to be K0,1700 K = 83.9 GPa, dKT/dP = 5.9(2), and dKT/dT = -0.063 GPa/K. The addition of carbon did not affect the isothermal bulk modulus (KT) of liquid Fe, but it decreased the dK/dT of liquid Fe. In the ρ-VP relationship, VP increases linearly with ρ and can be approximated as VP (m/s) = -6786(506) + 1537(71) × ρ (g/cm3), suggesting that Birch's law is valid for liquid Fe-C at the present P-T conditions. Our results imply that at the conditions of the lunar core, the elastic properties of an Fe-C core are more affected by temperature than those of Fe-S core.

  14. Photoacoustic Sounds from Meteors

    NASA Astrophysics Data System (ADS)

    Spalding, Richard; Tencer, John; Sweatt, William; Conley, Benjamin; Hogan, Roy; Boslough, Mark; Gonzales, Gigi; Spurný, Pavel

    2017-02-01

    Concurrent sound associated with very bright meteors manifests as popping, hissing, and faint rustling sounds occurring simultaneously with the arrival of light from meteors. Numerous instances have been documented with -11 to -13 brightness. These sounds cannot be attributed to direct acoustic propagation from the upper atmosphere for which travel time would be several minutes. Concurrent sounds must be associated with some form of electromagnetic energy generated by the meteor, propagated to the vicinity of the observer, and transduced into acoustic waves. Previously, energy propagated from meteors was assumed to be RF emissions. This has not been well validated experimentally. Herein we describe experimental results and numerical models in support of photoacoustic coupling as the mechanism. Recent photometric measurements of fireballs reveal strong millisecond flares and significant brightness oscillations at frequencies ≥40 Hz. Strongly modulated light at these frequencies with sufficient intensity can create concurrent sounds through radiative heating of common dielectric materials like hair, clothing, and leaves. This heating produces small pressure oscillations in the air contacting the absorbers. Calculations show that -12 brightness meteors can generate audible sound at ~25 dB SPL. The photoacoustic hypothesis provides an alternative explanation for this longstanding mystery about generation of concurrent sounds by fireballs.

  15. Photoacoustic Sounds from Meteors

    PubMed Central

    Spalding, Richard; Tencer, John; Sweatt, William; Conley, Benjamin; Hogan, Roy; Boslough, Mark; Gonzales, GiGi; Spurný, Pavel

    2017-01-01

    Concurrent sound associated with very bright meteors manifests as popping, hissing, and faint rustling sounds occurring simultaneously with the arrival of light from meteors. Numerous instances have been documented with −11 to −13 brightness. These sounds cannot be attributed to direct acoustic propagation from the upper atmosphere for which travel time would be several minutes. Concurrent sounds must be associated with some form of electromagnetic energy generated by the meteor, propagated to the vicinity of the observer, and transduced into acoustic waves. Previously, energy propagated from meteors was assumed to be RF emissions. This has not been well validated experimentally. Herein we describe experimental results and numerical models in support of photoacoustic coupling as the mechanism. Recent photometric measurements of fireballs reveal strong millisecond flares and significant brightness oscillations at frequencies ≥40 Hz. Strongly modulated light at these frequencies with sufficient intensity can create concurrent sounds through radiative heating of common dielectric materials like hair, clothing, and leaves. This heating produces small pressure oscillations in the air contacting the absorbers. Calculations show that −12 brightness meteors can generate audible sound at ~25 dB SPL. The photoacoustic hypothesis provides an alternative explanation for this longstanding mystery about generation of concurrent sounds by fireballs. PMID:28145486

  16. Photoacoustic sounds from meteors

    DOE PAGES

    Spalding, Richard; Tencer, John; Sweatt, William; ...

    2017-02-01

    Concurrent sound associated with very bright meteors manifests as popping, hissing, and faint rustling sounds occurring simultaneously with the arrival of light from meteors. Numerous instances have been documented with –11 to –13 brightness. These sounds cannot be attributed to direct acoustic propagation from the upper atmosphere for which travel time would be several minutes. Concurrent sounds must be associated with some form of electromagnetic energy generated by the meteor, propagated to the vicinity of the observer, and transduced into acoustic waves. Previously, energy propagated from meteors was assumed to be RF emissions. This has not been well validated experimentally.more » Herein we describe experimental results and numerical models in support of photoacoustic coupling as the mechanism. Recent photometric measurements of fireballs reveal strong millisecond flares and significant brightness oscillations at frequencies ≥40 Hz. Strongly modulated light at these frequencies with sufficient intensity can create concurrent sounds through radiative heating of common dielectric materials like hair, clothing, and leaves. This heating produces small pressure oscillations in the air contacting the absorbers. Calculations show that –12 brightness meteors can generate audible sound at ~25 dB SPL. As a result, the photoacoustic hypothesis provides an alternative explanation for this longstanding mystery about generation of concurrent sounds by fireballs.« less

  17. Ocean bottom seismometer pressure gauge observations of the 15 July 2009 Mw 7.8 Dusky Sound, New Zealand tsunami and simulations

    NASA Astrophysics Data System (ADS)

    Heidarzadeh, M.; Takagawa, T.; Satake, K.; Gusman, A. R.; Watada, S.; Sheehan, A. F.

    2016-12-01

    Tsunami observations made by pressure gauges installed on Ocean Bottom Seismometers (OBSPG) have provided new opportunities in tsunami research. OBSPG observations have two main advantages over Deep-Ocean Assessment and Reporting of Tsunami (DART) records namely: 1) they come with large numbers (several tens) and dense distribution with spacing of 10-50 km versus 200-4000 km of DARTs, 2) they have high frequency with sampling rates of 40-100 Hz versus that of 0.016 Hz for DARTs. Here, we analyzed the OBSPG records of the 15 July 2009 Mw 7.8 Dusky Sound (New Zealand) tsunami. At the time of the tsunami, 30 OBSPGs equipped with differential pressure gauges (DPG) were deployed at offshore New Zealand. The tsunami also was recorded on two DARTs and four tide gauge stations. While tsunami signals were fully hidden in high-frequency recordings of the OBSPGs, we were able to clearly extract the tsunami signals by applying re-sampling, filtering, and de-convolving the DPG instrument response. In our processed OBSPG tsunami data, the tsunami arrival times were clear and the signals had periods in the range of 10-20 min which is the expected period range for a tsunami from Mw 7.8 earthquake. Numerical modeling of tsunami was conducted by using the tsunami source proposed by Beavan et al. (2010) [Geophys. J. Int. 183]. Simulations were able to fairly reproduce the observations from OBSPG, DART and tide gauge stations. However, the match for DART and tide gauge records was better than that for OBSPGs. While the observed arrival times of the first peak matched well with those of simulations for the OBSPG waveforms, the match for amplitude was not good enough. The OBS tsunami records used in this study are freely available at http://www.iris.edu.

  18. Average ambulatory measures of sound pressure level, fundamental frequency, and vocal dose do not differ between adult females with phonotraumatic lesions and matched control subjects

    PubMed Central

    Van Stan, Jarrad H.; Mehta, Daryush D.; Zeitels, Steven M.; Burns, James A.; Barbu, Anca M.; Hillman, Robert E.

    2015-01-01

    Objectives Clinical management of phonotraumatic vocal fold lesions (nodules, polyps) is based largely on assumptions that abnormalities in habitual levels of sound pressure level (SPL), fundamental frequency (f0), and/or amount of voice use play a major role in lesion development and chronic persistence. This study used ambulatory voice monitoring to evaluate if significant differences in voice use exist between patients with phonotraumatic lesions and normal matched controls. Methods Subjects were 70 adult females: 35 with vocal fold nodules or polyps and 35 age-, sex-, and occupation-matched normal individuals. Weeklong summary statistics of voice use were computed from anterior neck surface acceleration recorded using a smartphone-based ambulatory voice monitor. Results Paired t-tests and Kolmogorov-Smirnov tests resulted in no statistically significant differences between patients and matched controls regarding average measures of SPL, f0, vocal dose measures, and voicing/voice rest periods. Paired t-tests comparing f0 variability between the groups resulted in statistically significant differences with moderate effect sizes. Conclusions Individuals with phonotraumatic lesions did not exhibit differences in average ambulatory measures of vocal behavior when compared with matched controls. More refined characterizations of underlying phonatory mechanisms and other potentially contributing causes are warranted to better understand risk factors associated with phonotraumatic lesions. PMID:26024911

  19. Audiometric earphone discomfort level and hearing aid saturation sound pressure level for a 90 decibel input signal (SSPL90) as measured in the human ear canal.

    PubMed

    Leijon, A; Harford, E; Lidén, G; Ringdahl, A; Dahlberg, A K

    1983-01-01

    The acoustical problems involved in matching the saturation sound pressure level for a 90 dB input signal (SSPL90) of a hearing aid to individual discomfort level were investigated. The real ear SPL (RE/SSPL90) produced by a supra-aural earphone used when measuring uncomfortable loudness (UCL), and RE/SSPL90 produced by three different hearing aids at 90 dB SPL input, were measured for nine subjects, using a miniature microphone technique, and compared to the corresponding coupler levels used when matching hearing aid maximum output to UCL. It was found that a hearing aid often gives about 5 dB, and sometimes 10 dB, higher RE/SPLs than the earphone, if the hearing aid output levels, as measured in a 2-cc coupler (IEC126), are equal to the earphone output levels as measured in a 6-cc coupler (NBS9A). It is recommended that a safety margin of at least 5 dB be used in the preliminary fitting when matching hearing aid SSPL90 to the patient's UCL, converted to dB SPL.

  20. Categorizing Sounds

    DTIC Science & Technology

    1988-09-30

    Classification) CatemorizinR Sounds 12. PERSONAL AUTHOR(S) Dr. Gremory R. Lockhead 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Year, Month,Day) S...variability in judgments of univariate sounds depends on what stimuli occurred recently (sequence effects), what stimuli might occur (set and range effects...CLASSIFICATION OF TH IS PAGE UNCLASSIFIED CATEGORIZING SOUNDS =- Gregory R. Lockhead Department of Psychology 3 Duke University -4 Durham, North Carolina 27706

  1. Sound Absorbers

    NASA Astrophysics Data System (ADS)

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  2. Differential sound level meter

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J. (Inventor)

    1977-01-01

    Small differences between relatively high sound pressure levels at two different microphone sites are measured by a device which provides electrical insertion voltages (pilot voltages) as a a means for continuously monitoring the gains of two acoustical channels. The difference between two pilot voltages is utilized to force the gain of one channel to track the other channel.

  3. Decoupling of first sound from second sound in dilute 3He-superfluid 4He mixtures

    NASA Astrophysics Data System (ADS)

    Riekki, T. S.; Manninen, M. S.; Tuoriniemi, J. T.

    2016-12-01

    Bulk superfluid helium supports two sound modes: first sound is an ordinary pressure wave, while second sound is a temperature wave, unique to superfluid systems. These sound modes do not usually exist independently, but rather variations in pressure are accompanied by variations in temperature, and vice versa. We studied the coupling between first and second sound in dilute 3He -superfluid 4He mixtures, between 1.6 and 2.2 K, at 3He concentrations ranging from 0% to 11%, under saturated vapor pressure, using a quartz tuning fork oscillator. Second sound coupled to first sound can create anomalies in the resonance response of the fork, which disappear only at very specific temperatures and concentrations, where two terms governing the coupling cancel each other, and second sound and first sound become decoupled.

  4. Acoustoelasticity. [sound-structure interaction

    NASA Technical Reports Server (NTRS)

    Dowell, E. H.

    1977-01-01

    Sound or pressure variations inside bounded enclosures are investigated. Mathematical models are given for determining: (1) the interaction between the sound pressure field and the flexible wall of a Helmholtz resonator; (2) coupled fluid-structural motion of an acoustic cavity with a flexible and/or absorbing wall; (3) acoustic natural modes in multiple connected cavities; and (4) the forced response of a cavity with a flexible and/or absorbing wall. Numerical results are discussed.

  5. Evaluating The Relation of Trace Fracture Inclination and Sound Pressure Level and Time-of-flight QUS Parameters Using Computational Simulation

    NASA Astrophysics Data System (ADS)

    Rosa, P. T.; Fontes-Pereira, A. J.; Matusin, D. P.; von Krüger, M. A.; Pereira, W. C. A.

    Bone healing is a complex process that stars after the occurrence of a fracture to restore bone optimal conditions. The gold standards for bone status evaluation are the dual energy X-ray absorptiometry and the computerized tomography. Ultrasound-based technologies have some advantages as compared to X-ray technologies: nonionizing radiation, portability and lower cost among others. Quantitative ultrasound (QUS) has been proposed in literature as a new tool to follow up the fracture healing process. QUS relates the ultrasound propagation with the bone tissue condition (normal or pathological), so, a change in wave propagation may indicate a variation in tissue properties. The most used QUS parameters are time-of-flight (TOF) and sound pressure level (SPL) of the first arriving signal (FAS). In this work, the FAS is the well known lateral wave. The aim of this work is to evaluate the relation of the TOF and SPL of the FAS and fracture inclination trace in two stages of bone healing using computational simulations. Four fracture geometries were used: normal and oblique with 30, 45 and 60 degrees. The TOF average values were 63.23 μs, 63.14 μs, 63.03 μs 62.94 μs for normal, 30, 45 and 60 degrees respectively and average SPL values were -3.83 dB -4.32 dB, -4.78 dB, -6.19 dB for normal, 30, 45 and 60 degrees respectively. The results show an inverse pattern between the amplitude and time-of-flight. These values seem to be sensible to fracture inclination trace, and in future, can be used to characterize it.

  6. Chronic exposure to broadband noise at moderate sound pressure levels spatially shifts tone-evoked responses in the rat auditory midbrain.

    PubMed

    Lau, Condon; Pienkowski, Martin; Zhang, Jevin W; McPherson, Bradley; Wu, Ed X

    2015-11-15

    Noise-induced hearing disorders are a significant public health concern. One cause of such disorders is exposure to high sound pressure levels (SPLs) above 85 dBA for eight hours/day. High SPL exposures occur in occupational and recreational settings and affect a substantial proportion of the population. However, an even larger proportion is exposed to more moderate SPLs for longer durations. Therefore, there is significant need to better understand the impact of chronic, moderate SPL exposures on auditory processing, especially in the absence of hearing loss. In this study, we applied functional magnetic resonance imaging (fMRI) with tonal acoustic stimulation on an established broadband rat exposure model (65 dB SPL, 30 kHz low-pass, 60 days). The auditory midbrain response of exposed subjects to 7 kHz stimulation (within exposure bandwidth) shifts dorsolaterally to regions that typically respond to lower stimulation frequencies. This shift is quantified by a region of interest analysis that shows that fMRI signals are higher in the dorsolateral midbrain of exposed subjects and in the ventromedial midbrain of control subjects (p<0.05). Also, the center of the responsive region in exposed subjects shifts dorsally relative to that of controls (p<0.05). A similar statistically significant shift (p<0.01) is observed using 40 kHz stimulation (above exposure bandwidth). The results suggest that high frequency midbrain regions above the exposure bandwidth spatially expand due to exposure. This expansion shifts lower frequency regions dorsolaterally. Similar observations have previously been made in the rat auditory cortex. Therefore, moderate SPL exposures affect auditory processing at multiple levels, from the auditory cortex to the midbrain. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Constraints on the Properties of the Moon's Outer Core from High-Pressure Sound Velocity Measurements on Fe-S Liquids

    NASA Astrophysics Data System (ADS)

    Jing, Z.; Wang, Y.; Kono, Y.; Yu, T.; Sakamaki, T.; Park, C.; Rivers, M. L.; Sutton, S. R.; Shen, G.

    2013-12-01

    Geophysical observations based on lunar seismology and laser ranging strongly suggest that the Moon's iron core is partially molten. Similar to Earth and other terrestrial planets, light elements, such as sulfur, silicon, carbon, and oxygen, are likely present in the lunar core. Determining the light element concentration in the outer core is of vital importance to the understanding of the structure, dynamics, and chemical evolution of the Moon, as well as the enigmatic history of the lunar dynamo. Among the candidate elements, sulfur is the preferred major light element in the lunar outer due to its high abundance in the parent bodies of iron meteorites, its high solubility in liquid Fe at the lunar core pressure (~5 GPa), and its strong effects on reducing the density, velocity, and freezing temperature of the core. In this study, we conducted in-situ sound velocity measurements on liquid samples of four different compositions, including pure Fe, Fe-10wt%S, Fe-20wt%S, and Fe-27wt%S, at pressure and temperature conditions up to 8 GPa and 1973 K (encompassing the entire lunar depth range), using the Kawai-type multi-anvil device at the GSECARS beamline 13-ID-D and the Paris-Edinburgh cell at HPCAT beamline 16-BM-B. Our results show that the velocity of Fe-rich liquids increases upon compression, decreases with increasing sulfur content, and is nearly independent of temperature. Compared to the seismic velocity of the outer core, our velocity data constrain the sulfur content at 4×2 wt%, indicating a significantly denser (6.4×0.4 g/cm3) and hotter (1860×60 K) outer core than previously estimated. A new lunar structure model incorporating available geophysical observations points to a smaller core radius. Our model also suggests a top-down solidification scenario for the evolution of the lunar core. Such an 'iron snow' process may have been an important mechanism for the growth of the inner core.

  8. The relevance of low-frequency sound properties for performance and pleasantness

    NASA Astrophysics Data System (ADS)

    Persson Waye, Kerstin; Bengtsson, Johanna

    2004-05-01

    The sound environment in the workplace has been found to influence performance, stress, mood, and well-being after work. However few studies can provide dose-response relationships and little is known of the importance of sound-quality aspects for adverse effects on critical tasks or task requirements. We have, during the last 8 years, been engaged in studies investigating the critical performance effects due to the presence of low frequencies (20-200 Hz) in sounds. The main hypotheses on critical effects derived from studies in the general environment were that low-frequency noise induced great annoyance, concentration difficulties, and was difficult to filter out or habituate to. On the other hand, results from truck drivers indicated that low-frequency sounds may lead to reduced alertness and increased sleepiness. In total, three studies were designed with regard to these hypotheses, all of them with the intention to be applicable to office and control room environment, using equivalent A-weighted sound-pressure levels of 40 and 45 dB. The fourth study investigated the importance of sound properties in low-frequency sounds for the perception of pleasantness. The results will be presented and discussed in relation to noise assessment aspects. [Work supported by Swedish Council for Working Life and Social Research.

  9. Sound Advice.

    ERIC Educational Resources Information Center

    Popke, Michael

    2000-01-01

    Discusses the planning and decision-making process in acquiring sound equipment for sports stadiums that will help make the experience of fans more pleasurable. The bidding process and use of consultants is explored. (GR)

  10. Sound Advice.

    ERIC Educational Resources Information Center

    Popke, Michael

    2000-01-01

    Discusses the planning and decision-making process in acquiring sound equipment for sports stadiums that will help make the experience of fans more pleasurable. The bidding process and use of consultants is explored. (GR)

  11. Atmospheric sound propagation

    NASA Technical Reports Server (NTRS)

    Cook, R. K.

    1969-01-01

    The propagation of sound waves at infrasonic frequencies (oscillation periods 1.0 - 1000 seconds) in the atmosphere is being studied by a network of seven stations separated geographically by distances of the order of thousands of kilometers. The stations measure the following characteristics of infrasonic waves: (1) the amplitude and waveform of the incident sound pressure, (2) the direction of propagation of the wave, (3) the horizontal phase velocity, and (4) the distribution of sound wave energy at various frequencies of oscillation. Some infrasonic sources which were identified and studied include the aurora borealis, tornadoes, volcanos, gravity waves on the oceans, earthquakes, and atmospheric instability waves caused by winds at the tropopause. Waves of unknown origin seem to radiate from several geographical locations, including one in the Argentine.

  12. Relation between annoyance and single-number quantities for rating heavy-weight floor impact sound insulation in wooden houses.

    PubMed

    Ryu, Jongkwan; Sato, Hiroshi; Kurakata, Kenji; Hiramitsu, Atsuo; Tanaka, Manabu; Hirota, Tomohito

    2011-05-01

    This study investigated the relation between annoyance and single-number quantities to rate heavy-weight floor impact sound insulation. Laboratory experiments were conducted to evaluate the subjective response of annoyance resulting from heavy-weight floor impact sounds recorded in wooden houses. Stimuli had two typical spectra and their modified versions, which simulate the precise change in frequency response resulting from insulation treatments. Results of the first experiment showed that the Zwicker's percentile loudness (N(5)) was the quantity to rate most well annoyance of heavy-weight impact sound over a wide sound level range. The second experiment revealed that arithmetic average (L(iFavg,Fmax)) of octave-band sound pressure levels measured using the time constant "fast" and Zwicker's percentile loudness (N(5)) much better described annoyance by the precise change in the sound spectrum attributable to insulation treatments than Japanese standardized single-number quantities (L(i,Fmax,r), L(iA,Fmax), and L(i,Fmax,Aw)) do. Japanese standardized single-number quantities using the A-weighting curve as a rating curve were found to be excessively influenced by the 63 Hz octave-band sound level and have the great sound level-dependences in the relation with subjective ratings.

  13. Sound Guard

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Lubrication technology originally developed for a series of NASA satellites has produced a commercial product for protecting the sound fidelity of phonograph records. Called Sound Guard, the preservative is a spray-on fluid that deposits a microscopically thin protective coating which reduces friction and prevents the hard diamond stylus from wearing away the softer vinyl material of the disc. It is marketed by the Consumer Products Division of Ball Corporation, Muncie, Indiana. The lubricant technology on which Sound Guard is based originated with NASA's Orbiting Solar Observatory (OSO), an Earth-orbiting satellite designed and built by Ball Brothers Research Corporation, Boulder, Colorado, also a division of Ball Corporation. Ball Brothers engineers found a problem early in the OSO program: known lubricants were unsuitable for use on satellite moving parts that would be exposed to the vacuum of space for several months. So the company conducted research on the properties of materials needed for long life in space and developed new lubricants. They worked successfully on seven OSO flights and attracted considerable attention among other aerospace contractors. Ball Brothers now supplies its "Vac Kote" lubricants and coatings to both aerospace and non-aerospace industries and the company has produced several hundred variations of the original technology. Ball Corporation expanded its product line to include consumer products, of which Sound Guard is one of the most recent. In addition to protecting record grooves, Sound Guard's anti-static quality also retards particle accumulation on the stylus. During comparison study by a leading U.S. electronic laboratory, a record not treated by Sound Guard had to be cleaned after 50 plays and the stylus had collected a considerable number of small vinyl particles. The Sound Guard-treated disc was still clean after 100 plays, as was its stylus.

  14. A WEIGHT-DRIVEN KYMOGRAPH.

    PubMed

    McLaughlin, A R

    1928-07-20

    (1) Herein has been described a stand for supporting the drum, a device for starting and stopping the drum and a circuit-breaker for a weight-driven kymograph (2) This device has proved satisfactory for recording simple muscular contractions, for securing data for the determination of the speed of the nerve-impulse and for determining reaction times (3) With but a little training in technic, college freshmen have secured very good graphs with this apparatus (4) This machine, exclusive of the drum, has been constructed at less than one third the cost of a spring-driven kymograph, and the drum of the latter may readily be used for either, since but a few minutes are required to make the shift.

  15. Underwater Sound Transmission

    DTIC Science & Technology

    1970-04-10

    OVER SPHERICAL DIVERGENCE LOSS VERSUS HORIZONTAL RANGE 49 20 ABSORPTION IN SEA WATER 51 21 ABSORPTION IN SEA WATER IN DEEP SOUND CHANNEL 52 22...isospeed condition. In warm water , a negative temperature gradient of greater magnitude is required to balance pressure increase with depth than in...cold water . Any combination of temperature and temperature gradient above the curve produces upward refraction. Any combination below the curve produces

  16. Geophysical Sounding

    NASA Astrophysics Data System (ADS)

    Blake, E.

    1998-01-01

    Of the many geophysical remote-sensing techniques available today, a few are suitable for the water ice-rich, layered material expected at the north martian ice cap. Radio echo sounding has been used for several decades to determine ice thickness and internal structure. Selection of operating frequency is a tradeoff between signal attenuation (which typically increases with frequency and ice temperature) and resolution (which is proportional to wavelength). Antenna configuration and size will be additional considerations for a mission to Mars. Several configurations for ice-penetrating radar systems are discussed: these include orbiter-borne sounders, sounding antennas trailed by balloons and penetrators, and lander-borne systems. Lander-borne systems could include short-wave systems capable of resolving fine structure and layering in the upper meters beneath the lander. Spread-spectrum and deconvolution techniques can be used to increase the depth capability of a radar system. If soundings over several locations are available (e.g., with balloons, rovers, or panning short-wave systems), then it will be easier to resolve internal layering, variations in basal reflection coefficient (from which material properties may be inferred), and the geometry of nonhorizontal features. Sonic sounding has a long history in oil and gas exploration. It is, however, unlikely that large explosive charges, or even swept-frequency techniques such as Vibroseis, would be suitable for a Polar lander -- these systems are capable of penetrating several kilometers of material at frequencies of 10-200 Hz, but the energy required to generate the sound waves is large and potentially destructive. The use of audio-frequency and ultrasonic sound generated by piezoelectric crystals is discussed as a possible method to explore layering and fine features in the upper meters of the ice cap. Appropriate choice of transducer(s) will permit operation over a range of fixed or modulated frequencies

  17. Sound Solutions

    ERIC Educational Resources Information Center

    Starkman, Neal

    2007-01-01

    Poor classroom acoustics are impairing students' hearing and their ability to learn. However, technology has come up with a solution: tools that focus voices in a way that minimizes intrusive ambient noise and gets to the intended receiver--not merely amplifying the sound, but also clarifying and directing it. One provider of classroom audio…

  18. Sound Solutions

    ERIC Educational Resources Information Center

    Starkman, Neal

    2007-01-01

    Poor classroom acoustics are impairing students' hearing and their ability to learn. However, technology has come up with a solution: tools that focus voices in a way that minimizes intrusive ambient noise and gets to the intended receiver--not merely amplifying the sound, but also clarifying and directing it. One provider of classroom audio…

  19. PREFACE: Aerodynamic sound Aerodynamic sound

    NASA Astrophysics Data System (ADS)

    Akishita, Sadao

    2010-02-01

    The modern theory of aerodynamic sound originates from Lighthill's two papers in 1952 and 1954, as is well known. I have heard that Lighthill was motivated in writing the papers by the jet-noise emitted by the newly commercialized jet-engined airplanes at that time. The technology of aerodynamic sound is destined for environmental problems. Therefore the theory should always be applied to newly emerged public nuisances. This issue of Fluid Dynamics Research (FDR) reflects problems of environmental sound in present Japanese technology. The Japanese community studying aerodynamic sound has held an annual symposium since 29 years ago when the late Professor S Kotake and Professor S Kaji of Teikyo University organized the symposium. Most of the Japanese authors in this issue are members of the annual symposium. I should note the contribution of the two professors cited above in establishing the Japanese community of aerodynamic sound research. It is my pleasure to present the publication in this issue of ten papers discussed at the annual symposium. I would like to express many thanks to the Editorial Board of FDR for giving us the chance to contribute these papers. We have a review paper by T Suzuki on the study of jet noise, which continues to be important nowadays, and is expected to reform the theoretical model of generating mechanisms. Professor M S Howe and R S McGowan contribute an analytical paper, a valuable study in today's fluid dynamics research. They apply hydrodynamics to solve the compressible flow generated in the vocal cords of the human body. Experimental study continues to be the main methodology in aerodynamic sound, and it is expected to explore new horizons. H Fujita's study on the Aeolian tone provides a new viewpoint on major, longstanding sound problems. The paper by M Nishimura and T Goto on textile fabrics describes new technology for the effective reduction of bluff-body noise. The paper by T Sueki et al also reports new technology for the

  20. Use of a pressure plate to analyse the toe-heel load redistribution underneath a normal shoe and a shoe with a wide toe in sound warmblood horses at the walk and trot.

    PubMed

    Oomen, A M; Oosterlinck, M; Pille, F; Sonneveld, D C; Gasthuys, F; Back, W

    2012-10-01

    The objective of this study was to use a pressure plate to quantify the toe-heel load redistribution in the forelimbs of sound warmblood horses with normal shoes and shoes with a wide toe and narrow branches, used empirically in the treatment of superficial digital flexor tendon or suspensory ligament injuries. In a crossover-design study, six horses, randomly shod with normal shoes and shoes with a wide toe, were led over a dynamically calibrated pressure plate to record data from both forelimbs. There were no significant differences between both shoes in the toe-heel index of stance time, peak vertical force and vertical impulse. For the adapted shoe, the peak vertical pressure was slightly lower and was exerted slightly earlier in the stance phase, albeit not significantly. However, the significantly larger toe contact area of the adapted shoe resulted in a significantly lower total vertical pressure in the toe region. Hence, the pressure plate adequately visualised the individual loading of the toe and heel region, and clearly demonstrated the altered pressure distribution underneath the shoe with a wide toe. Although further research on a deformable surface is needed to confirm this hypothesis, the pressure redistribution from the toe to the heels could promote sinking of the heels in arena footing, thereby mimicking the biomechanical effects of a toe wedge and providing a rationale for its application in the treatment of SDFT or SL injuries. The pressure measuring equipment used in this study can offer to the clinician a diagnostic tool for the evaluation of the load distribution underneath the equine hoof and for the fine-tuning of corrective shoeing.

  1. Healing sounds.

    PubMed

    Brewer, J F

    1998-02-01

    This article explores Guzzetta's (1988) notion that musical vibrations that are in tune with our human vibratory pattern could have a profound healing effect on the entire body. The question of why music therapy works for some and not others is addressed in the paper and solutions are offered. Central to utilizing therapeutic music and healing sounds with positive effects is an understanding of the principles and theories of sound and harmonics, in order to comprehend its capacity to achieve therapeutic, psychological and physical change. Some of these principles and theories are explored in this article. There is a focus on strategies for the holistic nurse who wishes to use this knowledge to facilitate communication and balance between the mind and body of the patient.

  2. Sounds of Space

    NASA Astrophysics Data System (ADS)

    Gurnett, D. A.

    2005-12-01

    Starting in the early 1960s, spacecraft-borne plasma wave instruments revealed that space is filled with an astonishing variety of radio and plasma wave sounds, which have come to be called "sounds of space." For over forty years these sounds have been collected and played to a wide variety of audiences, often as the result of press conferences or press releases involving various NASA projects for which the University of Iowa has provided plasma wave instruments. This activity has led to many interviews on local and national radio programs, and occasionally on programs haviang world-wide coverage, such as the BBC. As a result of this media coverage, we have been approached many times by composers requesting copies of our space sounds for use in their various projects, many of which involve electronic synthesis of music. One of these collaborations led to "Sun Rings," which is a musical event produced by the Kronos Quartet that has played to large audiences all over the world. With the availability of modern computer graphic techniques we have recently been attempting to integrate some of these sound of space into an educational audio/video web site that illustrates the scientific principles involved in the origin of space plasma waves. Typically I try to emphasize that a substantial gas pressure exists everywhere in space in the form of an ionized gas called a plasma, and that this plasma can lead to a wide variety of wave phenomenon. Examples of some of this audio/video material will be presented.

  3. Helicopter flight noise tests about the influence of rotor-rotational and forward speed changes on the characteristics of the immitted sound

    NASA Astrophysics Data System (ADS)

    Heller, H. H.; Splettstoesser, W.

    1983-04-01

    The noise characteristics of three modern medium-weight twin-turbo engine helicopters were determined using flight tests which collected straight-level overflight noise data. The data were analyzed spectrally and in terms of several commonly applied noise-metrics, such as the maximum. A-weighted Sound Pressure Level L sub A and the maximum Overall Sound Pressure Level OASPL. The results indicate the decisive effect of the advancing blade tip Mach-number on the emitted sound, which shows the growing influence of high-speed impulsive noise components on the noise signature at blade Mach-numbers beyond approximately 0.8. It is found that both the maximum tone-corrected and the Effective Perceived Noise Level observed on the ground for a helicopter in horizontal overflight depend strongly on the forward flight and the main rotor rotational speed.

  4. The influence of sounds on posture control.

    PubMed

    Siedlecka, Bożena; Sobera, Małgorzata; Sikora, Aleksandra; Drzewowska, Izabela

    2015-01-01

    It is still not clear which parameters of sound are the most significant for body reactions and whether the way of sound reception plays a role in body control. The purpose of this study was to determine the influence of frequency, spectrum and loudness of sounds on posture control in healthy women and men. The study subjects were 29 young adults who were submitted to a 60-second standing test in the bipedal stance on the force platform (AMTI). During the tests, 3 sinusoidal sounds with various timing and 2 musical sounds (guitar and piano) of the frequency 225 Hz, 1000 Hz and 4000 Hz were applied through headphones. The centre of pressure (COP) amplitude was registered. The sway area and COP mean velocity were computed. It was found that high frequency sounds contributed to a significant decrease of sway area values. No significant influence of low frequency sounds on posture control was observed. The influence of the sound spectrum (timbre) on posture control is limited; only the crescendo spectrum improves the body stability in the bipedal stance and not the music spectrum as guitar and piano. The loudness of sound, although extremely high, is not the cause of postural control changing in relation to lower loudness. No effect of gender was found in terms of body stability under different sound conditions. Based on the results, it can be argued that, in general, in a bipedal stance in terms of stability high sound frequency improves posture control, whereas sound spectrum and intensity show a limited impact.

  5. Resolution enhanced sound detecting apparatus

    NASA Technical Reports Server (NTRS)

    Kendall, J. M. (Inventor)

    1979-01-01

    An apparatus is described for enhancing the resolution of a sound detector of the type which includes an acoustic mirror for focusing sound from an object onto a microphone to enable the determination of the location from which the sound arises. The enhancement apparatus includes an enclosure which surrounds the space between the mirror and microphone, and contains a gas heavier than air, such as Freon, through which sound moves slower and therefore with a shorter wavelength than in air, so that a mirror of given size has greater resolving power. An acoustically transparent front wall of the enclosure which lies forward of the mirror, can include a pair of thin sheets with pressured air between them, to form an end of the region of heavy gas into a concave shape.

  6. A preliminary study on pressure-plate evaluation of forelimb toe-heel and mediolateral hoof balance on a hard vs. a soft surface in sound ponies at the walk and trot.

    PubMed

    Oosterlinck, M; Royaux, E; Back, W; Pille, F

    2014-11-01

    Thus far, pressure-plate analysis has been limited to measurements on a hard surface, whereas equine athletes routinely perform on a deformable substrate. To explore pressure-plate analysis on arena footing. Nonrandomised crossover study using noninvasive techniques. Five sound, unshod ponies were walked and trotted over a pressure plate in 2 different conditions. In the first session, the plate was covered with only a 5 mm rubber mat, and in the second session, with an additional 50 mm layer of sand and synthetic fibres. Limb loading and timing variables (peak vertical force, vertical impulse, peak vertical pressure, hoof contact area and stance phase duration) were obtained. Toe-heel and mediolateral hoof balance of the vertical force were calculated throughout stance (126 Hz). Peak vertical force, vertical impulse, peak vertical pressure and stance phase duration were decreased on the soft substrate, while hoof contact area increased. At impact, there was more even load distribution between the toe and heel region on the soft vs. hard surface. At mid-stance, there was more loading of the toe region on the soft compared with the hard surface. At impact, there was more even load distribution between lateral and medial on the soft vs. hard surface at walk, but not at trot. Comparison of observed vs. expected impulse indicated that the main factor involved in the lower loading on the soft surface is the dampening effect of the soft substrate, although definitive conclusions require concurrent force-plate analysis. The pressure plate permitted quantitative evaluation of hoof balance of the vertical force on a deformable surface at the walk and trot and proved that there is more even load distribution on arena footing. © 2013 EVJ Ltd.

  7. Experimental validation of sound field control with a circular double-layer array of loudspeakers.

    PubMed

    Chang, Ji-Ho; Jacobsen, Finn

    2013-04-01

    This paper is concerned with experimental validation of a recently proposed method of controlling sound fields with a circular double-layer array of loudspeakers [Chang and Jacobsen, J. Acoust. Soc. Am. 131(6), 4518-4525 (2012)]. The double-layer of loudspeakers is realized with 20 pairs of closed-box loudspeakers mounted back-to-back. Source strengths are obtained with several solution methods by modeling loudspeakers as a weighted combination of monopoles and dipoles. Sound pressure levels of the controlled sound fields are measured inside and outside the array in an anechoic room, and performance indices are calculated. The experimental results show that a method of combining pure contrast maximization with a pressure matching technique provides only a small error in the listening zone between the desired and the reproduced fields, and at the same time reduces the sound level in the quiet zone as expected in the simulation studies well above the spatial Nyquist frequency except at a few frequencies. It is also shown that errors in the positions of the loudspeakers can be critical to the results at frequencies where the distance between the inner and the outer array is close to half a wavelength.

  8. Generalized acoustic energy density based active noise control in single frequency diffuse sound fields.

    PubMed

    Xu, Buye; Sommerfeldt, Scott D

    2014-09-01

    In a diffuse sound field, prior research has established that a secondary source can theoretically achieve perfect cancellation at an error microphone in the far field of the secondary source. However, the sound pressure level is generally only reduced in a small zone around the error sensor, and at a distance half of a wavelength away from the error sensor, the averaged sound pressure level will be increased by more than 10 dB. Recently an acoustic energy quantity, referred to as the generalized acoustic energy density (GED), has been introduced. The GED is obtained by using a weighting factor in the formulation of total acoustic energy density. Different values of the weighting factor can be chosen for different applications. When minimizing the GED at the error sensor, one can adjust the weighting factor to increase the spatial extent of the "quiet zone" and to achieve a desired balance between the degree of attenuation in the quiet zone and the total energy added into the sound field.

  9. Is Sound Exposure Level a Convenient Metric to Characterize Fatiguing Sounds? A Study in Beluga Whales.

    PubMed

    Supin, Alexander; Popov, Vladimir; Nechaev, Dmitry; Sysueva, Evgenia; Rozhnov, Viatcheslav

    2016-01-01

    Both the level and duration of fatiguing sounds influence temporary threshold shifts (TTSs) in odontocetes. These two parameters were combined into a sound exposure level (SEL). In the beluga whale Delphinapterus leucas, TTSs were investigated at various sound pressure level (SPL)-to-duration ratios at a specific SEL. At low SPL-to-duration ratios, the dependence was positive: shorter high-level sounds produced greater TTSs than long low-level sounds of the same SEL. At high SPL-to-duration ratios, the dependence was negative: long low-level sounds produced greater TTSs than short high-level sounds of the same SEL. Thus, the validity of SEL as a metric for fatiguing sound efficiency is limited.

  10. Method of sound synthesis

    DOEpatents

    Miner, Nadine E.; Caudell, Thomas P.

    2004-06-08

    A sound synthesis method for modeling and synthesizing dynamic, parameterized sounds. The sound synthesis method yields perceptually convincing sounds and provides flexibility through model parameterization. By manipulating model parameters, a variety of related, but perceptually different sounds can be generated. The result is subtle changes in sounds, in addition to synthesis of a variety of sounds, all from a small set of models. The sound models can change dynamically according to changes in the simulation environment. The method is applicable to both stochastic (impulse-based) and non-stochastic (pitched) sounds.

  11. Molybdenum Sound Velocity and Shear Strength Softening

    NASA Astrophysics Data System (ADS)

    Nguyen, Jeffrey; Akin, Minta; Chau, Ricky; Fratandouno, Dayne; Ambrose, Pat; Fat'yanov, Oleg; Asimow, Paul; Holmes, Neil

    2013-06-01

    We recently carried out a series of light-gas gun experiments to measure molybdenum acoustic sound speed up to 5 Mbars on the Hugoniot. Our measured sound speeds increase linearly with pressure up to 2.6 Mbars and taper off near the melting pressure. The gradual leveling off of sound speed suggests a possible loss of shear strength near the melt. A linear extrapolation of our data to zero pressure is in good agreement with the sound speed measured at ambient condition. The results indicate that molybdenum remains in the bcc phase on the Hugoniot up to the melting pressure. There is no bcc solid phase transition on the Hugoniot as previously reported. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  12. Moving sound source localization based on triangulation method

    NASA Astrophysics Data System (ADS)

    Miao, Feng; Yang, Diange; Wen, Junjie; Lian, Xiaomin

    2016-12-01

    This study develops a sound source localization method that extends traditional triangulation to moving sources. First, the possible sound source locating plane is scanned. Secondly, for each hypothetical source location in this possible plane, the Doppler effect is removed through the integration of sound pressure. Taking advantage of the de-Dopplerized signals, the moving time difference of arrival (MTDOA) is calculated, and the sound source is located based on triangulation. Thirdly, the estimated sound source location is compared to the original hypothetical location and the deviations are recorded. Because the real sound source location leads to zero deviation, the sound source can be finally located by minimizing the deviation matrix. Simulations have shown the superiority of MTDOA method over traditional triangulation in case of moving sound sources. The MTDOA method can be used to locate moving sound sources with as high resolution as DAMAS beamforming, as shown in the experiments, offering thus a new method for locating moving sound sources.

  13. The maverick heart sound.

    PubMed

    Witt, Chance M; Miranda, William R; Newman, Darrell B

    2016-07-01

    An asymptomatic 29-year-old woman presented for prenatal counselling. She had a history of a heart murmur since childhood and a previous echocardiogram suggesting 'enlargement of the heart'. Physical exam revealed normal jugular venous pressure and contour. Precordial palpation was unremarkable. Auscultation, however, was abnormal; findings on inspiration and expiration are presented in Figure 1, sound clip. Based on the phonocardiogram and online supplementary audio clip, which of the following is correct? An early diastolic filling sound (S3) is heard, indicating increased right ventricular filling pressures.An ejection click without respiratory variation and a systolic ejection murmur are heard, consistent with bicuspid aortic valve stenosis.An ejection click with respiratory variation and a systolic ejection murmur are heard, consistent with pulmonic valve stenosis.A holosystolic murmur with inspiratory augmentation is heard, indicating tricuspid regurgitation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  14. Field acoustic measurements of high-speed train sound along BTIR

    NASA Astrophysics Data System (ADS)

    Yu, HuaHua; Li, JiaChun

    2013-02-01

    In this paper, single-point field measurements of noise radiated from high-speed trains were performed at two sites along Beijing-Tianjin intercity railway (BTIR), aiming at acquiring the realistic acoustic data for validation and verification of physical model and computational prediction. The measurements showed that A-weighted sound pressure levels (SPLs) were between 80 and 87 dBA as trains passed. The maximum noise occurred at the moment when the pantograph arrived, suggesting that pantograph noise was one of the most significant sources. Sound radiated from high-speed trains of BTIR was a typical broadband spectrum with most acoustic power restricted in the range of medium-high frequency from about 400 Hz to 5 kHz. Aerodynamic noise was shown to be the dominant one over other acoustic sources for high-speed trains.

  15. Moth hearing and sound communication.

    PubMed

    Nakano, Ryo; Takanashi, Takuma; Surlykke, Annemarie

    2015-01-01

    Active echolocation enables bats to orient and hunt the night sky for insects. As a counter-measure against the severe predation pressure many nocturnal insects have evolved ears sensitive to ultrasonic bat calls. In moths bat-detection was the principal purpose of hearing, as evidenced by comparable hearing physiology with best sensitivity in the bat echolocation range, 20-60 kHz, across moths in spite of diverse ear morphology. Some eared moths subsequently developed sound-producing organs to warn/startle/jam attacking bats and/or to communicate intraspecifically with sound. Not only the sounds for interaction with bats, but also mating signals are within the frequency range where bats echolocate, indicating that sound communication developed after hearing by "sensory exploitation". Recent findings on moth sound communication reveal that close-range (~ a few cm) communication with low-intensity ultrasounds "whispered" by males during courtship is not uncommon, contrary to the general notion of moths predominantly being silent. Sexual sound communication in moths may apply to many eared moths, perhaps even a majority. The low intensities and high frequencies explain that this was overlooked, revealing a bias towards what humans can sense, when studying (acoustic) communication in animals.

  16. Time-domain simulation of sound production of the sho

    NASA Astrophysics Data System (ADS)

    Hikichi, Takafumi; Osaka, Naotoshi; Itakura, Fumitada

    2003-02-01

    A physical model based on the sound production mechanism of the sho is proposed with intention of applying it to sound synthesis. Time-domain simulation was done using this model, and effects of the tube length and blowing pressure on the sounding frequency and sounds spectra were investigated. The reed vibration, pressure variation inside the tube, and threshold blowing pressure for oscillation were measured by artificially blowing air into the sho. The experimental results are in acceptable agreement with simulation results in terms of the relationships between tube length and threshold pressure and between tube length and the sounding frequency. In addition, recorded sound waveforms and simulated ones have a common feature in the sense that high-frequency components of their spectra increase with increasing blowing pressure. Further, it is concluded that a sho reed acts as an ``outward-striking valve.''

  17. Sound velocity of δ-AlOOH up to core-mantle boundary pressures: Implications for the seismic anomalies induced by hydrated sediment in subducting slabs

    NASA Astrophysics Data System (ADS)

    Mashino, I.; Murakami, M.; Ohtani, E.

    2014-12-01

    Recent seismic tomography studies indicate that some of the subducting slabs stagnate at the mantle transition zone. Subducting slabs generally comprise lithological layers of sediments, mid-ocean ridge basalt and peridotite. Some amount of water is believed to exist as hydrous minerals in sediments. Therefore, it is essential to understand the effect of hydrous minerals in sediments on global circulation of hydrogen in deep earth. Many hydrous minerals are not stable under the pressure-temperature conditions of the lower mantle. However, recent studies show that δ-AlOOH, which exists in a sediment layer of subducting slabs below 600 km depth, is stable up to the base of the lowermost mantle. This phase is a possible carrier and reservoir of water in cold slabs subducting into the deep mantle. We have conducted high pressure acoustic wave velocity measurements of δ-AlOOH using Brillouin spectroscopy and also we explored the chemical bonding of δ-AlOOH by Raman spectroscopy at high pressure in a diamond anvil cell up to 134 GPa. The result shows that δ-AlOOH becomes harder at pressures above 6 GPa due to the hydrogen bonding symmetrization and has a higher VS compared to those of the major minerals in the transition zone, such as wadsleyite, ringwoodite, and majorite. Therefore, the existence of δ-AlOOH phase might account for the positive Vs anomaly at 600 km depth beneath northwest Pacific subduction zone. In some stagnated slabs, VS at 600 km depth is 2 % faster than that of PREM. If sediments stagnate in the transition zone, the positive Vs anomaly at 600 km depth would be accounted for by the stagnated sediments containing δ-AlOOH in the transition zone.

  18. Sound Generating Mechanism of Frog Shaped Guiros

    NASA Astrophysics Data System (ADS)

    Iwatsuki, Nobuyuki; Morikawa, Koichi

    A frog shaped guiro is a wooden percussion instrument with an open-ended cave. By rubbing dorsal fins like saw blades on a back of the guiro with a wooden stick, the guiro generates the sound like a frog's voice. The exciting force, response acceleration and radiating sound pressure were measured with accelerometers on the stick and guiro and a condenser microphone and then the relation between the impulsively exciting force and sound pressure was revealed. A three-dimensional solid model of the guiro was built by use of an X-ray CT scanner device and a finite element model composed of tetrahedral elements was then obtained. The FEM modal analysis revealed that the frog shaped guiro had four dominant modes of vibration which was characterized by motion of mouth of the guiro such as the yawn mode and grinding teeth mode. The frequency spectrum of the sound pressure radiating from the frog shaped guiro excited by sequential impulsive forces moving along the dorsal fins was theoretically estimated. Since the estimated sound pressure agreed well with the measured one, the sound radiating from the guiro like a frog's voice could be reproduced. It was also revealed that the variation of driving point mobility of the dorsal fins and amplitude of the exciting force affected to generate the sound like a frog's voice.

  19. Counterexamples concerning a weighted L^2 projection

    NASA Astrophysics Data System (ADS)

    Xu, Jinchao

    1991-10-01

    Counterexamples are given to show that some results concerning a weighted {L^2} projection presented earlier by Bramble and the author are sharp, i.e., that certain error and stability estimates are impossible in some cases.

  20. Improving the Sound Pressure Level of Two-Dimensional Audio Actuators by Coating Single-Walled Carbon Nanotubes on Piezoelectric Films.

    PubMed

    Um, Keehong

    2015-10-01

    As devices for amplifying or transforming electronic signals into audible signals through electromechanical operations, acoustic actuators in the form of loudspeakers are usually solid structures in three dimensional space. Recently there has been increasing demand for mobile electronic devices, such as mobile phones, to become smaller, thinner, and lighter. In contrast to a three dimensional audio system with magnets, we have invented a new type of flexible two dimensional device by utilizing the reverse piezoelectric effect in certain piezoelectric materials. Crystalline piezoelectric materials show electromechanical interaction between the mechanical state and the electrically-charged state. The piezoelectric effect is a reversible process in that materials exhibiting the direct piezoelectric effect (the internal generation of electrical charge resulting from an applied mechanical force) also exhibit the reverse piezoelectric effect (the internal generation of a mechanical strain resulting from an applied electrical field). We have adopted the plasma surface treatment in order to put coating materials on the surface of piezoelectric film. We compared two kinds of coating material, indium tin oxide and single-walled carbon nanotube, and found that single-walled carbon nanotube shows better performance. The results showed improvement of output power in a wider range of operating frequency; for the surface resistance of 0.5 kΩ/square, the single-walled CNT shows the range of operating frequency to be 0.75-17.5 kHz, but ITO shows 2.5-13.4 kHz. For the surface resistance of 1 kΩ/square, single-walled CNT shows the range of operating frequency to be 0.81-17 kHz, but ITO shows it cannot generate audible sound.

  1. Calculating Speed of Sound

    NASA Astrophysics Data System (ADS)

    Bhatnagar, Shalabh

    2017-01-01

    Sound is an emerging source of renewable energy but it has some limitations. The main limitation is, the amount of energy that can be extracted from sound is very less and that is because of the velocity of the sound. The velocity of sound changes as per medium. If we could increase the velocity of the sound in a medium we would be probably able to extract more amount of energy from sound and will be able to transfer it at a higher rate. To increase the velocity of sound we should know the speed of sound. If we go by the theory of classic mechanics speed is the distance travelled by a particle divided by time whereas velocity is the displacement of particle divided by time. The speed of sound in dry air at 20 °C (68 °F) is considered to be 343.2 meters per second and it won't be wrong in saying that 342.2 meters is the velocity of sound not the speed as it's the displacement of the sound not the total distance sound wave covered. Sound travels in the form of mechanical wave, so while calculating the speed of sound the whole path of wave should be considered not just the distance traveled by sound. In this paper I would like to focus on calculating the actual speed of sound wave which can help us to extract more energy and make sound travel with faster velocity.

  2. Dependence of sonochemical luminescence on various sound fields

    PubMed

    Yanagida; Masubuchi; Minagawa; Takimoto; Ogata; Koyama

    2000-03-01

    To understand the effect of the sound field on sonochemical luminescence, the exact sound pressure must be determined in each field. In this study it was determined by the Shlieren method, which measures the sound pressure without mixing the sound fields. We compared the efficiency of the sonochemical luminescence in three different ways: changing the diameter of the transducer, combining two transducers to obtain crossed propagating directions and surrounding the sound field by a glass cylinder. In the last case cylinders with various sizes were studied. We found that (i) at the same sound pressure, the larger transducer induces stronger luminescence per unit volume, (ii) driving two transducers produces stronger luminescence than the sum of each transducer and (iii) a glass cylinder surrounding the sound field induces stronger luminescence.

  3. Sound Localization in the Alligator

    PubMed Central

    Carr, Catherine E.

    2016-01-01

    In early tetrapods, it is assumed that the tympana were acoustically coupled through the pharynx and therefore inherently directional, acting as pressure difference receivers. The later closure of the middle ear cavity in turtles, archosaurs, and mammals is a derived condition, and would have changed the ear by decoupling the tympana. Isolation of the middle ears would then have led to selection for structural and neural strategies to compute sound source localization in both archosaurs and mammalian ancestors. In the archosaurs (birds and crocodilians) the presence of air spaces in the skull provided connections between the ears that have been exploited to improve directional hearing, while neural circuits mediating sound localization are well developed. In this review, we will focus primarily on directional hearing in crocodilians, where vocalization and sound localization are thought to be ecologically important, and indicate important issues still awaiting resolution. PMID:26048335

  4. Optical sound generation and amplification

    NASA Astrophysics Data System (ADS)

    Bass, Henry E.; Shields, F. D.

    1987-02-01

    This research has concentrated on sound propagation through a gas with a nonequilibrium distribution of internal states and the generation of sound following excitation of a fluid by a laser. When a sound wave propagates through a gas which has an overpopulation of vibrationally excited states, the wave can increase in amplitude while propagating. In simple terms, this represents a reversal of the absorption typically associated with vibrational relaxation. Amplification of a propagating wave has been theoretically predicted and experimentally observed for a gas undergoing chemical reaction and following an electrical discharge through a non-reacting mixture. Optoacoustic measurements have been completed in gaseous CO2 and SF6 and preliminary results are reported for several liquids. Following laser excitation of SF6 at low pressure, the gas actually cooled. A theoretical model for this behavior consistent with known energy transfer mechanisms has been developed and shown to be consistent with experiment measurements.

  5. Sound localization in the alligator.

    PubMed

    Bierman, Hilary S; Carr, Catherine E

    2015-11-01

    In early tetrapods, it is assumed that the tympana were acoustically coupled through the pharynx and therefore inherently directional, acting as pressure difference receivers. The later closure of the middle ear cavity in turtles, archosaurs, and mammals is a derived condition, and would have changed the ear by decoupling the tympana. Isolation of the middle ears would then have led to selection for structural and neural strategies to compute sound source localization in both archosaurs and mammalian ancestors. In the archosaurs (birds and crocodilians) the presence of air spaces in the skull provided connections between the ears that have been exploited to improve directional hearing, while neural circuits mediating sound localization are well developed. In this review, we will focus primarily on directional hearing in crocodilians, where vocalization and sound localization are thought to be ecologically important, and indicate important issues still awaiting resolution.

  6. Sounds Exaggerate Visual Shape

    ERIC Educational Resources Information Center

    Sweeny, Timothy D.; Guzman-Martinez, Emmanuel; Ortega, Laura; Grabowecky, Marcia; Suzuki, Satoru

    2012-01-01

    While perceiving speech, people see mouth shapes that are systematically associated with sounds. In particular, a vertically stretched mouth produces a /woo/ sound, whereas a horizontally stretched mouth produces a /wee/ sound. We demonstrate that hearing these speech sounds alters how we see aspect ratio, a basic visual feature that contributes…

  7. The Sound of Science

    ERIC Educational Resources Information Center

    Merwade, Venkatesh; Eichinger, David; Harriger, Bradley; Doherty, Erin; Habben, Ryan

    2014-01-01

    While the science of sound can be taught by explaining the concept of sound waves and vibrations, the authors of this article focused their efforts on creating a more engaging way to teach the science of sound--through engineering design. In this article they share the experience of teaching sound to third graders through an engineering challenge…

  8. Sound Insulation in Buildings

    NASA Astrophysics Data System (ADS)

    Gösele, K.; Schröder, E.

    Sound insulation between the different rooms inside a building or to the outside is a very complex problem. First, the airborne sound insulation of ceilings, walls, doors and windows is important. Second, a sufficient structure-borne sound insulation, also called impact sound insulation, for the ceilings, has to be provided especially. Finally, the service equipment should be sufficiently quiet.

  9. Sounds Exaggerate Visual Shape

    ERIC Educational Resources Information Center

    Sweeny, Timothy D.; Guzman-Martinez, Emmanuel; Ortega, Laura; Grabowecky, Marcia; Suzuki, Satoru

    2012-01-01

    While perceiving speech, people see mouth shapes that are systematically associated with sounds. In particular, a vertically stretched mouth produces a /woo/ sound, whereas a horizontally stretched mouth produces a /wee/ sound. We demonstrate that hearing these speech sounds alters how we see aspect ratio, a basic visual feature that contributes…

  10. The Sound of Science

    ERIC Educational Resources Information Center

    Merwade, Venkatesh; Eichinger, David; Harriger, Bradley; Doherty, Erin; Habben, Ryan

    2014-01-01

    While the science of sound can be taught by explaining the concept of sound waves and vibrations, the authors of this article focused their efforts on creating a more engaging way to teach the science of sound--through engineering design. In this article they share the experience of teaching sound to third graders through an engineering challenge…

  11. Meteorological effects on long-range outdoor sound propagation

    NASA Technical Reports Server (NTRS)

    Klug, Helmut

    1990-01-01

    Measurements of sound propagation over distances up to 1000 m were carried out with an impulse sound source offering reproducible, short time signals. Temperature and wind speed at several heights were monitored simultaneously; the meteorological data are used to determine the sound speed gradients according to the Monin-Obukhov similarity theory. The sound speed profile is compared to a corresponding prediction, gained through the measured travel time difference between direct and ground reflected pulse (which depends on the sound speed gradient). Positive sound speed gradients cause bending of the sound rays towards the ground yielding enhanced sound pressure levels. The measured meteorological effects on sound propagation are discussed and illustrated by ray tracing methods.

  12. Sound wave velocities of fcc Fe Ni alloy at high pressure and temperature by mean of inelastic X-ray scattering

    NASA Astrophysics Data System (ADS)

    Kantor, Anastasia P.; Kantor, Innokenty Yu.; Kurnosov, Alexander V.; Kuznetsov, Alexei Yu.; Dubrovinskaia, Natalia A.; Krisch, Michael; Bossak, Alexei A.; Dmitriev, Vladimir P.; Urusov, Vadim S.; Dubrovinsky, Leonid S.

    2007-09-01

    Knowledge of the high-pressure and high-temperature elasticity of Fe-Ni alloy with low (5-25%) Ni content is crucial for geosciences since it is probably the major component of the cores of the terrestrial planets and the Moon. Here we present a study of a FeNi alloy with 22 at.% of Ni to 72 GPa and 715 K, using inelastic X-ray scattering (IXS) and X-ray powder diffraction from polycrystalline material. The X-ray diffraction (XRD) study revealed stability of the face centred cubic (fcc) over the hexagonal close packed (hcp) phase in the whole investigated pressure-temperature range. The study presents first investigations of elasticity of fcc phase of iron-nickel Fe 0.78Ni 0.22 alloy. The isothermal equations of state were derived at room temperature and at 715 K ( K300 = 162(1) GPa, K300=4.97(1), V300 = 6.89(1) cm 3/mol; K715 = 160(1) GPa, K715=4.97(2), V715 = 6.96(1) cm 3/mol). Inelastic X-ray measurements allow the determination of the longitudinal acoustic wave velocity VP, and provide, combined with the measured equations of state, the full isotropic elasticity of the material. We found that within experimental errors our data follow the Birch's law. We did not observe any significant deviations for fcc Fe 0.78Ni 0.22 from elastic properties of pure ɛ-iron.

  13. On Categorizing Sounds

    DTIC Science & Technology

    1991-08-07

    PAasmum 200vwimW Context is important when people judge sounds , or attributes of sounds , or other stimuli. It is shown how judgments depend on what... sounds recently occurred (sequence effects), on how those sounds differ from one another (range effects), on the dis- tribution of those differences (set...results are consistent with a model havin two simple assumptions: Successive sounds (not just their attributes) assimilate toward one another in memory

  14. Iron sound velocities in shock wave experiments

    SciTech Connect

    Holmes, N C; Nguyen, J H

    1999-08-20

    We have performed a series of sound velocity measurements in iron at earth's core pressures. Experiments were carried out at shock pressures as high as 400 GPa, with particular emphasis on the pressure range between 175 GPa and 275 GPa. The measured sound velocities of iron at elevated pressures exhibit a single discontinuity near 250 GPa, corresponding to the vanishing of shear strength as the iron melts. A second discontinuity reported by Brown and McQueen in their previous iron sound velocity studies was not observed in our study. Our results are consistent with their data otherwise. Experimental details and error propagation techniques essential to determining the melting point will also be discussed.

  15. 40 CFR 205.54-1 - Low speed sound emission test procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Low speed sound emission test....54-1 Low speed sound emission test procedures. (a) Instrumentation. The following instrumentation... requirements of § 205.54-2. (2) A sound level calibrator. The calibrator shall produce a sound pressure...

  16. 40 CFR 205.54-1 - Low speed sound emission test procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Low speed sound emission test....54-1 Low speed sound emission test procedures. (a) Instrumentation. The following instrumentation... requirements of § 205.54-2. (2) A sound level calibrator. The calibrator shall produce a sound pressure...

  17. Sound wave propagation through glow discharge plasma

    NASA Astrophysics Data System (ADS)

    Stepaniuk, Vadim P.

    This work investigates the use of glow discharge plasma for acoustic wave manipulation. The broader goal is the suppression of aerodynamic noise using atmospheric glow discharge plasma as a sound barrier. Part of the effort was devoted to the development of a system for the generation of a large volume stable DC glow discharge in air both at atmospheric and at reduced pressures. The single tone sound wave propagation through the plasma was systematically studied. Attenuation of the acoustic wave passing through the glow discharge was measured for a range of experimental conditions including different discharge currents, electrode configurations, air pressures and sound frequencies including audible sound and ultrasound. Sound attenuation by glow discharge plasma as high as -28 dB was recorded in the experiments. Two types of possible mechanisms were considered that can potentially cause the observed sound attenuation. One is a global mechanism and the other is a local mechanism. The global mechanism considered is based on the reflection and refraction of acoustic wave due to the gas temperature gradients that form around the plasma. The local mechanism, on the other hand, is essentially the interaction of the acoustic wave with the plasma as it propagates inside the discharge and it can be viewed as a feedback system. Detailed temperature measurements, using laser-induced Rayleigh scattering technique, were carried out in the glow discharge plasma in order to evaluate the role of global mechanism in the observed attenuation. These measurements were made for a range of conditions in the atmospheric glow discharge. Theoretical analysis of the sound attenuation was carried out to identify the physical mechanism for the observed sound attenuation by plasma. It was demonstrated that the global mechanism is the dominant mechanism of sound attenuation. As a result of this study, the potentials and limitations of the plasma noise suppression technology were determined and

  18. Early sound symbolism for vowel sounds.

    PubMed

    Spector, Ferrinne; Maurer, Daphne

    2013-01-01

    Children and adults consistently match some words (e.g., kiki) to jagged shapes and other words (e.g., bouba) to rounded shapes, providing evidence for non-arbitrary sound-shape mapping. In this study, we investigated the influence of vowels on sound-shape matching in toddlers, using four contrasting pairs of nonsense words differing in vowel sound (/i/ as in feet vs. /o/ as in boat) and four rounded-jagged shape pairs. Crucially, we used reduplicated syllables (e.g., kiki vs. koko) rather than confounding vowel sound with consonant context and syllable variability (e.g., kiki vs. bouba). Toddlers consistently matched words with /o/ to rounded shapes and words with /i/ to jagged shapes (p < 0.01). The results suggest that there may be naturally biased correspondences between vowel sound and shape.

  19. Blood pressure reprogramming adapter assists signal recording

    NASA Technical Reports Server (NTRS)

    Vick, H. A.

    1967-01-01

    Blood pressure reprogramming adapter separates the two components of a blood pressure signal, a dc pressure signal and an ac Korotkoff sounds signal, so that the Korotkoff sounds are recorded on one channel as received while the dc pressure signal is converted to FM and recorded on a second channel.

  20. Sound wave transmission (image)

    MedlinePlus

    When sounds waves reach the ear, they are translated into nerve impulses. These impulses then travel to the brain where they are interpreted by the brain as sound. The hearing mechanisms within the inner ear, can ...

  1. The AVE/VAS 2: The 25 mb sounding data

    NASA Technical Reports Server (NTRS)

    Sienkiewicz, M. E.

    1982-01-01

    The rawinsonde sounding program for the AVE/VAS II experiment is described and tabulated data at 25 mb intervals are presented. Soundings were taken at 3 hr intervals, was an 18 hour period. An additional sounding was taken at the normal synoptic observation time. The processing soundings method is discussed, estimates of the RMS errors in the data are presented, and an example of contact data is given. Termination pressures of soundings taken in the meso-beta-scale network are tabulated, as are observations of ground temperature at a depth of 2 cm.

  2. Hierarchical spike coding of sound

    PubMed Central

    Karklin, Yan; Ekanadham, Chaitanya; Simoncelli, Eero P.

    2014-01-01

    Natural sounds exhibit complex statistical regularities at multiple scales. Acoustic events underlying speech, for example, are characterized by precise temporal and frequency relationships, but they can also vary substantially according to the pitch, duration, and other high-level properties of speech production. Learning this structure from data while capturing the inherent variability is an important first step in building auditory processing systems, as well as understanding the mechanisms of auditory perception. Here we develop Hierarchical Spike Coding, a two-layer probabilistic generative model for complex acoustic structure. The first layer consists of a sparse spiking representation that encodes the sound using kernels positioned precisely in time and frequency. Patterns in the positions of first layer spikes are learned from the data: on a coarse scale, statistical regularities are encoded by a second-layer spiking representation, while fine-scale structure is captured by recurrent interactions within the first layer. When fit to speech data, the second layer acoustic features include harmonic stacks, sweeps, frequency modulations, and precise temporal onsets, which can be composed to represent complex acoustic events. Unlike spectrogram-based methods, the model gives a probability distribution over sound pressure waveforms. This allows us to use the second-layer representation to synthesize sounds directly, and to perform model-based denoising, on which we demonstrate a significant improvement over standard methods. PMID:25356065

  3. Enlarge Your Sound Repertory

    ERIC Educational Resources Information Center

    Carle, Irmgard Lehrer; Martin, Isaiah

    1975-01-01

    Authors served up a variety of techniques for investigating sound sources and sound patterns. Have you considered creating a composition from breathing sounds? Or constructing a conversation in percussion? These ideas are included along with step-by-step directions for making nine percussion instruments. (Editor)

  4. Characterization of uncertainty in outdoor sound propagation predictions.

    PubMed

    Wilson, D Keith; Andreas, Edgar L; Weatherly, John W; Pettit, Chris L; Patton, Edward G; Sullivan, Peter P

    2007-05-01

    Predictive skill for outdoor sound propagation is assessed using high-resolution atmospheric fields from large-eddy simulations (LES). Propagation calculations through the full LES fields are compared to calculations through subsets of the LES fields that have been processed in typical ways, such as mean vertical profiles and instantaneous vertical profiles synchronized to the sound propagation. It is found that mean sound pressure levels can be predicted with low errors from the mean profiles, except in refractive shadow regions. Prediction of sound pressure levels for short-duration events is much less accurate, with errors of 8 -10 dB for near-ground propagation being typical.

  5. Sound propagation over uneven ground and irregular topography

    NASA Technical Reports Server (NTRS)

    Berthelot, Yves H.; Pierce, Allan D.; Zhou, Ji-Xun; Main, Geoffrey L.; Chen, Pei-Tai; Kearns, James A.; Chisholm, Nathaniel

    1987-01-01

    The acoustic impedance of the surface coverings used in the laboratory experiments on sound diffraction by topographical ridges was determined. The model, which was developed, takes into account full wave effects and the possibility of surface waves and predicts the sound pressure level at the receiver location relative to what would be expected if the flat surface were not present. The sound pressure level can be regarded as a function of frequency, sound speed in air, heights of source and receiver, and horizontal distance from source to receiver, as well as the real and imaginary parts of the surface impedance.

  6. Suppression of sound radiation to far field of near-field acoustic communication system using evanescent sound field

    NASA Astrophysics Data System (ADS)

    Fujii, Ayaka; Wakatsuki, Naoto; Mizutani, Koichi

    2016-01-01

    A method of suppressing sound radiation to the far field of a near-field acoustic communication system using an evanescent sound field is proposed. The amplitude of the evanescent sound field generated from an infinite vibrating plate attenuates exponentially with increasing a distance from the surface of the vibrating plate. However, a discontinuity of the sound field exists at the edge of the finite vibrating plate in practice, which broadens the wavenumber spectrum. A sound wave radiates over the evanescent sound field because of broadening of the wavenumber spectrum. Therefore, we calculated the optimum distribution of the particle velocity on the vibrating plate to reduce the broadening of the wavenumber spectrum. We focused on a window function that is utilized in the field of signal analysis for reducing the broadening of the frequency spectrum. The optimization calculation is necessary for the design of window function suitable for suppressing sound radiation and securing a spatial area for data communication. In addition, a wide frequency bandwidth is required to increase the data transmission speed. Therefore, we investigated a suitable method for calculating the sound pressure level at the far field to confirm the variation of the distribution of sound pressure level determined on the basis of the window shape and frequency. The distribution of the sound pressure level at a finite distance was in good agreement with that obtained at an infinite far field under the condition generating the evanescent sound field. Consequently, the window function was optimized by the method used to calculate the distribution of the sound pressure level at an infinite far field using the wavenumber spectrum on the vibrating plate. According to the result of comparing the distributions of the sound pressure level in the cases with and without the window function, it was confirmed that the area whose sound pressure level was reduced from the maximum level to -50 dB was

  7. Priming Gestures with Sounds

    PubMed Central

    Lemaitre, Guillaume; Heller, Laurie M.; Navolio, Nicole; Zúñiga-Peñaranda, Nicolas

    2015-01-01

    We report a series of experiments about a little-studied type of compatibility effect between a stimulus and a response: the priming of manual gestures via sounds associated with these gestures. The goal was to investigate the plasticity of the gesture-sound associations mediating this type of priming. Five experiments used a primed choice-reaction task. Participants were cued by a stimulus to perform response gestures that produced response sounds; those sounds were also used as primes before the response cues. We compared arbitrary associations between gestures and sounds (key lifts and pure tones) created during the experiment (i.e. no pre-existing knowledge) with ecological associations corresponding to the structure of the world (tapping gestures and sounds, scraping gestures and sounds) learned through the entire life of the participant (thus existing prior to the experiment). Two results were found. First, the priming effect exists for ecological as well as arbitrary associations between gestures and sounds. Second, the priming effect is greatly reduced for ecologically existing associations and is eliminated for arbitrary associations when the response gesture stops producing the associated sounds. These results provide evidence that auditory-motor priming is mainly created by rapid learning of the association between sounds and the gestures that produce them. Auditory-motor priming is therefore mediated by short-term associations between gestures and sounds that can be readily reconfigured regardless of prior knowledge. PMID:26544884

  8. Sound Generation Using a Magnetostrictive Microactuator

    NASA Astrophysics Data System (ADS)

    S. Albach, Thorsten; Horn, Peter; Sutor, Alexander; Lerch, Reinhard

    2011-04-01

    In this paper, we present the design and performance of a MEMS-device based on the magnetostrictive effect, which can be used as a micro-loudspeaker. The device basically consists of a comb structure of monomorph bending cantilevers with an active area up to 3.0×2.5 mm2. It produces a sound-pressure-level up to 101 dB at 400 Hz in a standard 2 ccm measurement volume. We show our measurement setup as well as a mechanic-acoustic-coupled lumped element model to calculate sound pressure. The model incorporates finite element results for mechanical behavior. Measurement results validate our model assumptions.

  9. Some sound transmission loss characteristics of typical general aviation structural materials

    NASA Technical Reports Server (NTRS)

    Roskam, J.; Van Dam, C.; Grosveld, F.; Durenberger, D.

    1978-01-01

    Experimentally measured sound transmission loss characteristics of flat aluminum panels with and without damping and stiffness treatment are presented and discussed. The effect of pressurization on sound transmission loss of flat aluminum panels is shown to be significant.

  10. Automatic blood pressure measuring system (M092)

    NASA Technical Reports Server (NTRS)

    Nolte, R. W.

    1977-01-01

    The Blood Pressure Measuring System is described. It measures blood pressure by the noninvasive Korotkoff sound technique on a continual basis as physical stress is imposed during experiment M092, Lower Body Negative Pressure, and experiment M171, Metabolic Activity.

  11. Automatic blood pressure measuring system (M092)

    NASA Technical Reports Server (NTRS)

    Nolte, R. W.

    1977-01-01

    The Blood Pressure Measuring System is described. It measures blood pressure by the noninvasive Korotkoff sound technique on a continual basis as physical stress is imposed during experiment M092, Lower Body Negative Pressure, and experiment M171, Metabolic Activity.

  12. Exposure to excessive sounds and hearing status in academic classical music students.

    PubMed

    Pawlaczyk-Łuszczyńska, Małgorzata; Zamojska-Daniszewska, Małgorzata; Dudarewicz, Adam; Zaborowski, Kamil

    2017-02-21

    The aim of this study was to assess hearing of music students in relation to their exposure to excessive sounds. Standard pure-tone audiometry (PTA) was performed in 168 music students, aged 22.5±2.5 years. The control group included 67 subjects, non-music students and non-musicians, aged 22.8±3.3 years. Data on the study subjects' musical experience, instruments in use, time of weekly practice and additional risk factors for noise-induced hearing loss (NIHL) were identified by means of a questionnaire survey. Sound pressure levels produced by various groups of instruments during solo and group playing were also measured and analyzed. The music students' audiometric hearing threshold levels (HTLs) were compared with the theoretical predictions calculated according to the International Organization for Standardization standard ISO 1999:2013. It was estimated that the music students were exposed for 27.1±14.3 h/week to sounds at the A-weighted equivalent-continuous sound pressure level of 89.9±6.0 dB. There were no significant differences in HTLs between the music students and the control group in the frequency range of 4000-8000 Hz. Furthermore, in each group HTLs in the frequency range 1000-8000 Hz did not exceed 20 dB HL in 83% of the examined ears. Nevertheless, high frequency notched audiograms typical of the noise-induced hearing loss were found in 13.4% and 9% of the musicians and non-musicians, respectively. The odds ratio (OR) of notching in the music students increased significantly along with higher sound pressure levels (OR = 1.07, 95% confidence interval (CI): 1.014-1.13, p < 0.05). The students' HTLs were worse (higher) than those of a highly screened non-noise-exposed population. Moreover, their hearing loss was less severe than that expected from sound exposure for frequencies of 3000 Hz and 4000 Hz, and it was more severe in the case of frequency of 6000 Hz. The results confirm the need for further studies and development of a hearing

  13. Derived autoequivalences and a weighted Beilinson resolution

    NASA Astrophysics Data System (ADS)

    Canonaco, Alberto; Karp, Robert L.

    2008-06-01

    Given a smooth stacky Calabi-Yau hypersurface X in a weighted projective space, we consider the functor G which is the composition of the following two autoequivalences of D(X): the first one is induced by the spherical object OX, while the second one is tensoring with OX(1). The main result of the paper is that the composition of G with itself w times, where w is the sum of the weights of the weighted projective space, is isomorphic to the autoequivalence "shift by 2". The proof also involves the construction of a Beilinson type resolution of the diagonal for weighted projective spaces, viewed as smooth stacks.

  14. Loudness of steady sounds - A new theory

    NASA Technical Reports Server (NTRS)

    Howes, W. L.

    1979-01-01

    A new mathematical theory for calculating the loudness of steady sounds from power summation and frequency interaction, based on psychoacoustic and physiological information, assuems that loudness is a subjective measure of the electrical energy transmitted along the auditory nerve to the central nervous system. The auditory system consists of the mechanical part modeled by a bandpass filter with a transfer function dependent on the sound pressure, and the electrical part where the signal is transformed into a half-wave reproduction represented by the electrical power in impulsive discharges transmitted along neurons comprising the auditory nerve. In the electrical part the neurons are distributed among artificial parallel channels with frequency bandwidths equal to 'critical bandwidths for loudness', within which loudness is constant for constant sound pressure. The total energy transmitted to the central nervous system is the sum of the energy transmitted in all channels, and the loudness is proportional to the square root of the total filtered sound energy distributed over all channels. The theory explains many psychoacoustic phenomena such as audible beats resulting from closely spaced tones, interaction of sound stimuli which affect the same neurons affecting loudness, and of individually subliminal sounds becoming audible if they lie within the same critical band.

  15. Loudness of steady sounds - A new theory

    NASA Technical Reports Server (NTRS)

    Howes, W. L.

    1979-01-01

    A new mathematical theory for calculating the loudness of steady sounds from power summation and frequency interaction, based on psychoacoustic and physiological information, assuems that loudness is a subjective measure of the electrical energy transmitted along the auditory nerve to the central nervous system. The auditory system consists of the mechanical part modeled by a bandpass filter with a transfer function dependent on the sound pressure, and the electrical part where the signal is transformed into a half-wave reproduction represented by the electrical power in impulsive discharges transmitted along neurons comprising the auditory nerve. In the electrical part the neurons are distributed among artificial parallel channels with frequency bandwidths equal to 'critical bandwidths for loudness', within which loudness is constant for constant sound pressure. The total energy transmitted to the central nervous system is the sum of the energy transmitted in all channels, and the loudness is proportional to the square root of the total filtered sound energy distributed over all channels. The theory explains many psychoacoustic phenomena such as audible beats resulting from closely spaced tones, interaction of sound stimuli which affect the same neurons affecting loudness, and of individually subliminal sounds becoming audible if they lie within the same critical band.

  16. Virtual Reality of Sound Generated from Vibrating Structures

    NASA Astrophysics Data System (ADS)

    KIM, S. J.; SONG, J. Y.

    2002-11-01

    The advancement of virtual reality (VR) technology in cyberspace is amazing, but its development is mainly concentrated on the visual part. In this paper, the development of VR technology to produce sound based on the exact physics is studied. Our main concern is on the sound generated from vibrating structures. This may be useful, for example, in apprehending sound field characteristics of an aircraft cabin in design stage. To calculate sound pressure from curved surface of a structure, a new integration scheme is developed in boundary element method. Several example problems are solved to confirm our integration scheme. The pressure distributions on a uniformly driven sphere and cylinders are computed and compared with analytic solutions, and radiation efficiency of a vibrating plate under one-dimensional flow is also calculated. Also, to realize sound through computer simulation, two concepts, "structure-oriented analysis" and "human-oriented analysis", are proposed. Using these concepts, virtual sound field of an aircraft cabin is created.

  17. High-speed imaging of sound using parallel phase-shifting interferometry.

    PubMed

    Ishikawa, Kenji; Yatabe, Kohei; Chitanont, Nachanant; Ikeda, Yusuke; Oikawa, Yasuhiro; Onuma, Takashi; Niwa, Hayato; Yoshii, Minoru

    2016-06-13

    Sound-field imaging, the visualization of spatial and temporal distribution of acoustical properties such as sound pressure, is useful for understanding acoustical phenomena. This study investigated the use of parallel phase-shifting interferometry (PPSI) with a high-speed polarization camera for imaging a sound field, particularly high-speed imaging of propagating sound waves. The experimental results showed that the instantaneous sound field, which was generated by ultrasonic transducers driven by a pure tone of 40 kHz, was quantitatively imaged. Hence, PPSI can be used in acoustical applications requiring spatial information of sound pressure.

  18. Graphene-on-paper sound source devices.

    PubMed

    Tian, He; Ren, Tian-Ling; Xie, Dan; Wang, Yu-Feng; Zhou, Chang-Jian; Feng, Ting-Ting; Fu, Di; Yang, Yi; Peng, Ping-Gang; Wang, Li-Gang; Liu, Li-Tian

    2011-06-28

    We demonstrate an interesting phenomenon that graphene can emit sound. The application of graphene can be expanded in the acoustic field. Graphene-on-paper sound source devices are made by patterning graphene on paper substrates. Three graphene sheet samples with the thickness of 100, 60, and 20 nm were fabricated. Sound emission from graphene is measured as a function of power, distance, angle, and frequency in the far-field. The theoretical model of air/graphene/paper/PCB board multilayer structure is established to analyze the sound directivity, frequency response, and efficiency. Measured sound pressure level (SPL) and efficiency are in good agreement with theoretical results. It is found that graphene has a significant flat frequency response in the wide ultrasound range 20-50 kHz. In addition, the thinner graphene sheets can produce higher SPL due to its lower heat capacity per unit area (HCPUA). The infrared thermal images reveal that a thermoacoustic effect is the working principle. We find that the sound performance mainly depends on the HCPUA of the conductor and the thermal properties of the substrate. The paper-based graphene sound source devices have highly reliable, flexible, no mechanical vibration, simple structure and high performance characteristics. It could open wide applications in multimedia, consumer electronics, biological, medical, and many other areas.

  19. Brief report: sound output of infant humidifiers.

    PubMed

    Royer, Allison K; Wilson, Paul F; Royer, Mark C; Miyamoto, Richard T

    2015-06-01

    The sound pressure levels (SPLs) of common infant humidifiers were determined to identify the likely sound exposure to infants and young children. This primary investigative research study was completed at a tertiary-level academic medical center otolaryngology and audiology laboratory. Five commercially available humidifiers were obtained from brick-and-mortar infant supply stores. Sound levels were measured at 20-, 100-, and 150-cm distances at all available humidifier settings. Two of 5 (40%) humidifiers tested had SPL readings greater than the recommended hospital infant nursery levels (50 dB) at distances up to 100 cm. In this preliminary study, it was demonstrated that humidifiers marketed for infant nurseries may produce appreciably high decibel levels. Further characterization of the effect of humidifier design on SPLs and further elucidation of ambient sound levels associated with hearing risk are necessary before definitive conclusions and recommendations can be made.

  20. Physics of thermo-acoustic sound generation

    NASA Astrophysics Data System (ADS)

    Daschewski, M.; Boehm, R.; Prager, J.; Kreutzbruck, M.; Harrer, A.

    2013-09-01

    We present a generalized analytical model of thermo-acoustic sound generation based on the analysis of thermally induced energy density fluctuations and their propagation into the adjacent matter. The model provides exact analytical prediction of the sound pressure generated in fluids and solids; consequently, it can be applied to arbitrary thermal power sources such as thermophones, plasma firings, laser beams, and chemical reactions. Unlike existing approaches, our description also includes acoustic near-field effects and sound-field attenuation. Analytical results are compared with measurements of sound pressures generated by thermo-acoustic transducers in air for frequencies up to 1 MHz. The tested transducers consist of titanium and indium tin oxide coatings on quartz glass and polycarbonate substrates. The model reveals that thermo-acoustic efficiency increases linearly with the supplied thermal power and quadratically with thermal excitation frequency. Comparison of the efficiency of our thermo-acoustic transducers with those of piezoelectric-based airborne ultrasound transducers using impulse excitation showed comparable sound pressure values. The present results show that thermo-acoustic transducers can be applied as broadband, non-resonant, high-performance ultrasound sources.

  1. Hazardous sound levels produced by extracorporeal shock wave lithotripsy

    SciTech Connect

    Lusk, R.P.; Tyler, R.S.

    1987-06-01

    Sound emitted from the Dornier system GmbH lithotriptor was found to be of sufficient intensity to warrant concern about noise-induced sensorineural hearing loss. The patients were exposed to impulses of 112 dB. peak sound pressure level. Operating room personnel were exposed to sounds of less intensity, although the number of impulses they were exposed to was much greater, thereby increasing the risk of hearing loss. Hearing protection is recommended for patients and operating room personnel.

  2. The sound of distance.

    PubMed

    Rabaglia, Cristina D; Maglio, Sam J; Krehm, Madelaine; Seok, Jin H; Trope, Yaacov

    2016-07-01

    Human languages may be more than completely arbitrary symbolic systems. A growing literature supports sound symbolism, or the existence of consistent, intuitive relationships between speech sounds and specific concepts. Prior work establishes that these sound-to-meaning mappings can shape language-related judgments and decisions, but do their effects generalize beyond merely the linguistic and truly color how we navigate our environment? We examine this possibility, relating a predominant sound symbolic distinction (vowel frontness) to a novel associate (spatial proximity) in five studies. We show that changing one vowel in a label can influence estimations of distance, impacting judgment, perception, and action. The results (1) provide the first experimental support for a relationship between vowels and spatial distance and (2) demonstrate that sound-to-meaning mappings have outcomes that extend beyond just language and can - through a single sound - influence how we perceive and behave toward objects in the world. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. A mechanism study of sound wave-trapping barriers.

    PubMed

    Yang, Cheng; Pan, Jie; Cheng, Li

    2013-09-01

    The performance of a sound barrier is usually degraded if a large reflecting surface is placed on the source side. A wave-trapping barrier (WTB), with its inner surface covered by wedge-shaped structures, has been proposed to confine waves within the area between the barrier and the reflecting surface, and thus improve the performance. In this paper, the deterioration in performance of a conventional sound barrier due to the reflecting surface is first explained in terms of the resonance effect of the trapped modes. At each resonance frequency, a strong and mode-controlled sound field is generated by the noise source both within and in the vicinity outside the region bounded by the sound barrier and the reflecting surface. It is found that the peak sound pressures in the barrier's shadow zone, which correspond to the minimum values in the barrier's insertion loss, are largely determined by the resonance frequencies and by the shapes and losses of the trapped modes. These peak pressures usually result in high sound intensity component impinging normal to the barrier surface near the top. The WTB can alter the sound wave diffraction at the top of the barrier if the wavelengths of the sound wave are comparable or smaller than the dimensions of the wedge. In this case, the modified barrier profile is capable of re-organizing the pressure distribution within the bounded domain and altering the acoustic properties near the top of the sound barrier.

  4. Sound: a non-invasive measure of cough intensity

    PubMed Central

    Matos, Sergio; Ward, Katie; Rafferty, Gerrard F; Moxham, John; Evans, David H; Birring, Surinder S

    2017-01-01

    Introduction Cough intensity is an important determinant of cough severity reported by patients. Cough sound analysis has been widely validated for the measurement of cough frequency but few studies have validated its use in the assessment of cough strength. We investigated the relationship between cough sound and physiological measures of cough strength. Methods 32 patients with chronic cough and controls underwent contemporaneous measurements of voluntary cough sound, flow and oesophageal pressure. Sound power, peak energy, rise-time, duration, peak-frequency, bandwidth and centroid-frequency were assessed and compared with physiological measures. The relationship between sound and subjective cough strength Visual Analogue Score (VAS), the repeatability of cough sounds and the effect of microphone position were also assessed. Results Sound power and energy correlated strongly with cough flow (median Spearman’s r=0.87–0.88) and oesophageal pressure (median Spearman’s r=0.89). Sound power and energy correlated strongly with cough strength VAS (median Spearman’s r=0.84–0.86) and were highly repeatable (intraclass correlation coefficient=0.93–0.94) but both were affected by change in microphone position. Conclusions Cough sound power and energy correlate strongly with physiological measures and subjective perception of cough strength. Power and energy are highly repeatable measures but the microphone position should be standardised. Our findings support the use of cough sound as an index of cough strength. PMID:28725446

  5. Sound: a non-invasive measure of cough intensity.

    PubMed

    Lee, Kai K; Matos, Sergio; Ward, Katie; Rafferty, Gerrard F; Moxham, John; Evans, David H; Birring, Surinder S

    2017-01-01

    Cough intensity is an important determinant of cough severity reported by patients. Cough sound analysis has been widely validated for the measurement of cough frequency but few studies have validated its use in the assessment of cough strength. We investigated the relationship between cough sound and physiological measures of cough strength. 32 patients with chronic cough and controls underwent contemporaneous measurements of voluntary cough sound, flow and oesophageal pressure. Sound power, peak energy, rise-time, duration, peak-frequency, bandwidth and centroid-frequency were assessed and compared with physiological measures. The relationship between sound and subjective cough strength Visual Analogue Score (VAS), the repeatability of cough sounds and the effect of microphone position were also assessed. Sound power and energy correlated strongly with cough flow (median Spearman's r=0.87-0.88) and oesophageal pressure (median Spearman's r=0.89). Sound power and energy correlated strongly with cough strength VAS (median Spearman's r=0.84-0.86) and were highly repeatable (intraclass correlation coefficient=0.93-0.94) but both were affected by change in microphone position. Cough sound power and energy correlate strongly with physiological measures and subjective perception of cough strength. Power and energy are highly repeatable measures but the microphone position should be standardised. Our findings support the use of cough sound as an index of cough strength.

  6. Distress sounds of thorny catfishes emitted underwater and in air: characteristics and potential significance.

    PubMed

    Knight, Lisa; Ladich, Friedrich

    2014-11-15

    Thorny catfishes produce stridulation (SR) sounds using their pectoral fins and drumming (DR) sounds via a swimbladder mechanism in distress situations when hand held in water and in air. It has been argued that SR and DR sounds are aimed at different receivers (predators) in different media. The aim of this study was to analyse and compare sounds emitted in both air and water in order to test different hypotheses on the functional significance of distress sounds. Five representatives of the family Doradidae were investigated. Fish were hand held and sounds emitted in air and underwater were recorded (number of sounds, sound duration, dominant and fundamental frequency, sound pressure level and peak-to-peak amplitudes). All species produced SR sounds in both media, but DR sounds could not be recorded in air for two species. Differences in sound characteristics between media were small and mainly limited to spectral differences in SR. The number of sounds emitted decreased over time, whereas the duration of SR sounds increased. The dominant frequency of SR and the fundamental frequency of DR decreased and sound pressure level of SR increased with body size across species. The hypothesis that catfish produce more SR sounds in air and more DR sounds in water as a result of different predation pressure (birds versus fish) could not be confirmed. It is assumed that SR sounds serve as distress sounds in both media, whereas DR sounds might primarily be used as intraspecific communication signals in water in species possessing both mechanisms. © 2014. Published by The Company of Biologists Ltd.

  7. Standing Sound Waves in Air with DataStudio

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2010-01-01

    Two experiments related to standing sound waves in air are adapted for using the ScienceWorkshop data-acquisition system with the DataStudio software from PASCO scientific. First, the standing waves are created by reflection from a plane reflector. The distribution of the sound pressure along the standing wave is measured. Second, the resonance…

  8. Standing Sound Waves in Air with DataStudio

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2010-01-01

    Two experiments related to standing sound waves in air are adapted for using the ScienceWorkshop data-acquisition system with the DataStudio software from PASCO scientific. First, the standing waves are created by reflection from a plane reflector. The distribution of the sound pressure along the standing wave is measured. Second, the resonance…

  9. Early sound symbolism for vowel sounds

    PubMed Central

    Spector, Ferrinne; Maurer, Daphne

    2013-01-01

    Children and adults consistently match some words (e.g., kiki) to jagged shapes and other words (e.g., bouba) to rounded shapes, providing evidence for non-arbitrary sound–shape mapping. In this study, we investigated the influence of vowels on sound–shape matching in toddlers, using four contrasting pairs of nonsense words differing in vowel sound (/i/ as in feet vs. /o/ as in boat) and four rounded–jagged shape pairs. Crucially, we used reduplicated syllables (e.g., kiki vs. koko) rather than confounding vowel sound with consonant context and syllable variability (e.g., kiki vs. bouba). Toddlers consistently matched words with /o/ to rounded shapes and words with /i/ to jagged shapes (p < 0.01). The results suggest that there may be naturally biased correspondences between vowel sound and shape. PMID:24349684

  10. Spatial resolution limits for the localization of noise sources using direct sound mapping

    NASA Astrophysics Data System (ADS)

    Fernandez Comesaña, D.; Holland, K. R.; Fernandez-Grande, E.

    2016-08-01

    One of the main challenges arising from noise and vibration problems is how to identify the areas of a device, machine or structure that produce significant acoustic excitation, i.e. the localization of main noise sources. The direct visualization of sound, in particular sound intensity, has extensively been used for many years to locate sound sources. However, it is not yet well defined when two sources should be regarded as resolved by means of direct sound mapping. This paper derives the limits of the direct representation of sound pressure, particle velocity and sound intensity by exploring the relationship between spatial resolution, noise level and geometry. The proposed expressions are validated via simulations and experiments. It is shown that particle velocity mapping yields better results for identifying closely spaced sound sources than sound pressure or sound intensity, especially in the acoustic near-field.

  11. The sound field in a finite cylindrical shell

    NASA Technical Reports Server (NTRS)

    Junger, M. C.

    1985-01-01

    The sound field excited by vibrating boundaries in a finite cylindrical space, e.g., in a cylindrical shell, differs from the pressure distribution in an infinite cylindrical shell of comparable structural wavelength by the pressure diffracted by the end caps. The latter pressure component is comparable in magnitude to the pressure generated by the vibrating cylindrical boundary, but does not introduce additional resonances or antiresonances. Finally, a third pressure component associated with end cap vibrations is formulated.

  12. Breaking the Sound Barrier

    ERIC Educational Resources Information Center

    Brown, Tom; Boehringer, Kim

    2007-01-01

    Students in a fourth-grade class participated in a series of dynamic sound learning centers followed by a dramatic capstone event--an exploration of the amazing Trashcan Whoosh Waves. It's a notoriously difficult subject to teach, but this hands-on, exploratory approach ignited student interest in sound, promoted language acquisition, and built…

  13. School Sound Level Study.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento.

    California has conducted on-site sound surveys of 36 different schools to determine the degree of noise, and thus disturbance, within the learning environment. This report provides the methodology and results of the survey, including descriptive charts and graphs illustrating typical desirable and undesirable sound levels. Results are presented…

  14. Categorization of Sounds

    ERIC Educational Resources Information Center

    Smits, Roel; Sereno, Joan; Jongman, Allard

    2006-01-01

    The authors conducted 4 experiments to test the decision-bound, prototype, and distribution theories for the categorization of sounds. They used as stimuli sounds varying in either resonance frequency or duration. They created different experimental conditions by varying the variance and overlap of 2 stimulus distributions used in a training phase…

  15. Exploring Noise: Sound Pollution.

    ERIC Educational Resources Information Center

    Rillo, Thomas J.

    1979-01-01

    Part one of a three-part series about noise pollution and its effects on humans. This section presents the background information for teachers who are preparing a unit on sound. The next issues will offer learning activities for measuring the effects of sound and some references. (SA)

  16. The sounds of nanotechnology

    NASA Astrophysics Data System (ADS)

    Campbell, Norah; Deane, Cormac; Murphy, Padraig

    2017-07-01

    Public perceptions of nanotechnology are shaped by sound in surprising ways. Our analysis of the audiovisual techniques employed by nanotechnology stakeholders shows that well-chosen sounds can help to win public trust, create value and convey the weird reality of objects on the nanoscale.

  17. Categorization of Sounds

    ERIC Educational Resources Information Center

    Smits, Roel; Sereno, Joan; Jongman, Allard

    2006-01-01

    The authors conducted 4 experiments to test the decision-bound, prototype, and distribution theories for the categorization of sounds. They used as stimuli sounds varying in either resonance frequency or duration. They created different experimental conditions by varying the variance and overlap of 2 stimulus distributions used in a training phase…

  18. Operational sounding algorithms

    NASA Technical Reports Server (NTRS)

    Smith, W. L.

    1980-01-01

    The analytical equations used to interpret TIROS-N sounding radiances for operational applications are presented. Both the National Environmental Satellite System (NESS) Global Operational Synoptic Scale and the NESS/University of Wisconsin (UW) North American Mesoscale Sounding Production Systems are considered.

  19. Inferring Agency from Sound

    ERIC Educational Resources Information Center

    Knoblich, Gunther; Repp, Bruno H.

    2009-01-01

    In three experiments we investigated how people determine whether or not they are in control of sounds they hear. The sounds were either triggered by participants' taps or controlled by a computer. The task was to distinguish between self-control and external control during active tapping, and during passive listening to a playback of the sounds…

  20. The Bosstown Sound.

    ERIC Educational Resources Information Center

    Burns, Gary

    Based on the argument that (contrary to critical opinion) the musicians in the various bands associated with Bosstown Sound were indeed talented, cohesive individuals and that the bands' lack of renown was partially a result of ill-treatment by record companies and the press, this paper traces the development of the Bosstown Sound from its…

  1. Low frequency sound propagation in activated carbon.

    PubMed

    Bechwati, F; Avis, M R; Bull, D J; Cox, T J; Hargreaves, J A; Moser, D; Ross, D K; Umnova, O; Venegas, R

    2012-07-01

    Activated carbon can adsorb and desorb gas molecules onto and off its surface. Research has examined whether this sorption affects low frequency sound waves, with pressures typical of audible sound, interacting with granular activated carbon. Impedance tube measurements were undertaken examining the resonant frequencies of Helmholtz resonators with different backing materials. It was found that the addition of activated carbon increased the compliance of the backing volume. The effect was observed up to the highest frequency measured (500 Hz), but was most significant at lower frequencies (at higher frequencies another phenomenon can explain the behavior). An apparatus was constructed to measure the effective porosity of the activated carbon as well as the number of moles adsorbed at sound pressures between 104 and 118 dB and low frequencies between 20 and 55 Hz. Whilst the results were consistent with adsorption affecting sound propagation, other phenomena cannot be ruled out. Measurements of sorption isotherms showed that additional energy losses can be caused by water vapor condensing onto and then evaporating from the surface of the material. However, the excess absorption measured for low frequency sound waves is primarily caused by decreases in surface reactance rather than changes in surface resistance.

  2. AVE/VAS 5: 25-mb sounding data

    NASA Technical Reports Server (NTRS)

    Sienkiewicz, M. E.

    1983-01-01

    The rawinsonde sounding program is described and tabulated data at 25 mb intervals for the 24 and 14 special stations participation in the experiment are presented. Soundings were taken at 3 hr intervals. The method of processing soundings is discussed briefly, estimates of the RMS errors in the data are presented, and an example of contact data is given. Termination pressures of soundings taken in the meso beta scale network are tabulated, as are observations of ground temperature at a depth of 2 cm.

  3. AVE/VAS 1: 25 mb sounding data

    NASA Technical Reports Server (NTRS)

    Sienkiewicz, M. E.

    1983-01-01

    The rawinsonde sounding program for the AVE/VAS I (shakedown) experiment is described. Tabulated data at 25-mb intervals for the 13 special rawinsonde stations and 1 National Weather Service station participating in the experiment are presented. Soundings were taken at 1200 and 1800 GMT on February 6, 1982, and at 0000 GMT on February 7, 1982. The method of processing soundings is discussed briefly, estimates of the RMS errors in the data are presented, and an example of contact data is given. Termination pressures of soundings are tabulated, as are observations of ground temperature at a depth of 2 cm.

  4. Classroom measurements of sound speed in fresh/saline water.

    PubMed

    Carman, Jessie C

    2012-03-01

    A tabletop apparatus permitting demonstrations and hands-on student exercises in the measurement of sound speed in water as a function of both temperature and salinity, at atmospheric pressure, is described. By measuring sound speed using a differential technique with a precisely measured path length difference Δx, errors due to uncertainty in original path length are minimized. The apparatus can be used to measure sound speed in freshwater baths of varying temperature and room temperature baths of varying salinities to provide the student a clear picture of sound speed variation along two axes. © 2012 Acoustical Society of America

  5. Sound speed in downhole flow measurement.

    PubMed

    Ünalmis, Ö Haldun

    2016-07-01

    This paper describes the use of sound speed in flow measurement applications in the high-pressure/high-temperature downhole environment. The propagation speed of a sound wave is a powerful tool to extract useful information from a flowing fluid medium in pipe whether the medium consists of a single-phase or multiphase flow. Considering the complex nature of the flow patterns and changing phase fractions from reservoir to surface, utilizing the propagation speed of sound of a fluid mixture is not a trivial task, especially if the interest is real-time flow measurement. The demanding applications span a wide spectrum from noisy medium originating from fast-moving gas/liquid flows to quiet medium originating from slow-moving liquid/liquid flows. In the current work, multiple flow loop tests are conducted in different facilities to evaluate the direct use of sound speed in flow rate measurement and the results are associated with real-life field examples. A tool analysis map is developed that addresses the use of sound speed for flow measurement under different scenarios. Although most examples are based on strain-based local sensing of the flow, the use of sound speed is independent of the methodology and can be implemented by other methods such as acoustic-based distributed sensing.

  6. Sound speed in the upper airways.

    PubMed

    Rice, D A

    1980-08-01

    We measured the velocity of audible sound at frequencies above 10 kHz to be 349 m.s-1 (+/- 1%, 95% confidence interval) in the upper airways of eupneic anesthetized dogs. It appears that the velocity of sound propagation is dependent on lumen gas composition, temperature, and mean flow speed. These three variables are sufficient to explain the velocity variations measured during tidal breathing. Lung volume, transpulmonary pressure, and bronchoactive drugs were not shown to have an appreciable effect on sound velocity. Model studies indicate that sound velocity is little affected by flow profile, lumen cross-sectional shape, or changes in lumen area with position. Flow speed proportionally changes the velocity of sound relative to the airway and therefore can be determined from sound propagation measurements. Dividing volume flow by flow speed gives airway cross-sectional area. Tracheal areas after normalization by the cube root of body weight were about half those previously reported. Acoustically inferred areas were confirmed by mechanical measurement.

  7. The sound manifesto

    NASA Astrophysics Data System (ADS)

    O'Donnell, Michael J.; Bisnovatyi, Ilia

    2000-11-01

    Computing practice today depends on visual output to drive almost all user interaction. Other senses, such as audition, may be totally neglected, or used tangentially, or used in highly restricted specialized ways. We have excellent audio rendering through D-A conversion, but we lack rich general facilities for modeling and manipulating sound comparable in quality and flexibility to graphics. We need coordinated research in several disciplines to improve the use of sound as an interactive information channel. Incremental and separate improvements in synthesis, analysis, speech processing, audiology, acoustics, music, etc. will not alone produce the radical progress that we seek in sonic practice. We also need to create a new central topic of study in digital audio research. The new topic will assimilate the contributions of different disciplines on a common foundation. The key central concept that we lack is sound as a general-purpose information channel. We must investigate the structure of this information channel, which is driven by the cooperative development of auditory perception and physical sound production. Particular audible encodings, such as speech and music, illuminate sonic information by example, but they are no more sufficient for a characterization than typography is sufficient for characterization of visual information. To develop this new conceptual topic of sonic information structure, we need to integrate insights from a number of different disciplines that deal with sound. In particular, we need to coordinate central and foundational studies of the representational models of sound with specific applications that illuminate the good and bad qualities of these models. Each natural or artificial process that generates informative sound, and each perceptual mechanism that derives information from sound, will teach us something about the right structure to attribute to the sound itself. The new Sound topic will combine the work of computer

  8. Sound attenuation by liners in a blown flap environment

    NASA Technical Reports Server (NTRS)

    Parthasarathy, S. P.; Vijayaraghavan, A.

    1980-01-01

    Sound propagation through a hot wall-jet flow over an absorbing wall is studied. The radiated sound field subject to the influence of flow convection and refraction is evaluated, and the nature of acoustic attenuation attributable to a sound absorbing liner is determined. Using a two-dimensional model, the noise field under the aircraft is also determined, and a slug-flow model is used to describe the influence of flow, density, and temperature on acoustic sources in jets. Results show significant changes in the radiated source due to the interference phenomenon, and a good absorber has the potential of changing the sound pressure range of variation to unity. A liner is also found to increase or decrease sound pressure, depending on the frequency.

  9. The Sound Wave Method for Measurement of Evaporation Coefficient

    NASA Astrophysics Data System (ADS)

    Nakamura, Shigeto; Yano, Takeru; Watanabe, Masao; Fujikawa, Shigeo

    A new method for measurement of evaporation coefficient using sound resonance experiment is proposed on the basis of a theory of molecular gas dynamics, by which the evaporation coefficient is expressed as a function of the amplitude of standing sound wave between a planar sound source and a vapor-liquid interface facing against it. To demonstrate the applicability of this method, we carried out test experiments under the condition of neither evaporation nor condensation for several initial pressures, 30, 50, 80 and 101 kPa, at room temperature. In the experiments, we measure the amplitude of standing wave with a resonant frequency generated in a cylindrical space filled with air and closed by liquid water. We utilize the second harmonics component excited by the nonlinearity of sound to determine the evaporation coefficient, thereby eliminating the electromagnetic noises from measured signals. We find that the amplitude of the second harmonics at sound resonance decreases with the decrease in the initial pressure.

  10. Perceiving sounds in the real world: an introduction to human complex sound perception.

    PubMed

    Yost, William A

    2007-05-01

    Arguably sensory systems, including audition, evolved allowing animals to navigate, find prey, avoid predators, mate, and, for some species, communicate. All of these essential functions require animals to determine objects in their environment. Vibrating objects produce a sound pressure wave that has the potential of informing an animal about these objects. Such acoustic information can make the organism aware of its immediate environment, provide useful information about that environment, allow for communication, and/or provide an esthetic value. However, sound has no dimensions of space, distance, shape, or size; and the auditory periphery of almost all animals contains peripheral receptors that code for the parameters of the sound pressure wave rather than information about sound sources per se. Thus, knowledge about sound sources gleaned from the peripheral neural code for the sound produced by a source is most likely computed in the brainstem and brain by means of an auditory neural computer. How this neural computer works and what other aspects of neural processing aid the computer is a mystery that is receiving a great deal of attention by many auditory scientists.

  11. Sound as artifact

    NASA Astrophysics Data System (ADS)

    Benjamin, Jeffrey L.

    A distinguishing feature of the discipline of archaeology is its reliance upon sensory dependant investigation. As perceived by all of the senses, the felt environment is a unique area of archaeological knowledge. It is generally accepted that the emergence of industrial processes in the recent past has been accompanied by unprecedented sonic extremes. The work of environmental historians has provided ample evidence that the introduction of much of this unwanted sound, or "noise" was an area of contestation. More recent research in the history of sound has called for more nuanced distinctions than the noisy/quiet dichotomy. Acoustic archaeology tends to focus upon a reconstruction of sound producing instruments and spaces with a primary goal of ascertaining intentionality. Most archaeoacoustic research is focused on learning more about the sonic world of people within prehistoric timeframes while some research has been done on historic sites. In this thesis, by way of a meditation on industrial sound and the physical remains of the Quincy Mining Company blacksmith shop (Hancock, MI) in particular, I argue for an acceptance and inclusion of sound as artifact in and of itself. I am introducing the concept of an individual sound-form, or sonifact , as a reproducible, repeatable, representable physical entity, created by tangible, perhaps even visible, host-artifacts. A sonifact is a sound that endures through time, with negligible variability. Through the piecing together of historical and archaeological evidence, in this thesis I present a plausible sonifactual assemblage at the blacksmith shop in April 1916 as it may have been experienced by an individual traversing the vicinity on foot: an 'historic soundwalk.' The sensory apprehension of abandoned industrial sites is multi-faceted. In this thesis I hope to make the case for an acceptance of sound as a primary heritage value when thinking about the industrial past, and also for an increased awareness and acceptance

  12. AVE/VAS 3: 25-mb sounding data

    NASA Technical Reports Server (NTRS)

    Sienkiewicz, M. E.

    1982-01-01

    The rawinsonde sounding program for the AVE/VAS 3 experiment is described. Tabulated data are presented at 25-mb intervals for the 24 National Weather Service stations and 14 special stations participating in the experiment. Soundings were taken at 3-hr intervals, beginning at 1200 GMT on March 27, 1982, and ending at 0600 GMT on March 28, 1982 (7 sounding times). An additional sounding was taken at the National Weather Service stations at 1200 GMT on March 28, 1982, at the normal synoptic observation time. The method of processing soundings is briefly discussed, estimates of the RMS errors in the data are presented, and an example of contact data is given. Termination pressures of soundings taken in the mesos-beta-scale network are tabulated, as are observations of ground temperature at a depth of 2 cm.

  13. Suppression of slag foaming by a sound wave.

    PubMed

    Komarov, S V; Kuwabara, M; Sano, M

    2000-10-01

    The aim of this work was to study the effects of sound frequency, sound intensity and viscosity of slag on the slag foaming rate and the steady-state foam height. Experiments were carried out using two slags (BaO-B2O3) melted at a temperature of 1223 or 1273 K, as well as water-glycerin solutions at room temperature. Low frequency sound waves (< 1.3 kHz) are found to be more effective in the slag foaming suppression than high frequency waves (1.3-12 kHz). The steady-state foam height decreases abruptly when the sound pressure reaches a threshold value that depends on sound frequency and liquid viscosity. The results can be explained in terms of enhancing the rates of liquid drainage and film rupture induced by sound.

  14. Multichannel sound reinforcement systems at work in a learning environment

    NASA Astrophysics Data System (ADS)

    Malek, John; Campbell, Colin

    2003-04-01

    Many people have experienced the entertaining benefits of a surround sound system, either in their own home or in a movie theater, but another application exists for multichannel sound that has for the most part gone unused. This is the application of multichannel sound systems to the learning environment. By incorporating a 7.1 surround processor and a touch panel interface programmable control system, the main lecture hall at the University of Michigan Taubman College of Architecture and Urban Planning has been converted from an ordinary lecture hall to a working audiovisual laboratory. The multichannel sound system is used in a wide variety of experiments, including exposure to sounds to test listeners' aural perception of the tonal characteristics of varying pitch, reverberation, speech transmission index, and sound-pressure level. The touch panel's custom interface allows a variety of user groups to control different parts of the AV system and provides preset capability that allows for numerous system configurations.

  15. Light aircraft sound transmission studies - Noise reduction model

    NASA Technical Reports Server (NTRS)

    Atwal, Mahabir S.; Heitman, Karen E.; Crocker, Malcolm J.

    1987-01-01

    Experimental tests conducted on the fuselage of a single-engine Piper Cherokee light aircraft suggest that the cabin interior noise can be reduced by increasing the transmission loss of the dominant sound transmission paths and/or by increasing the cabin interior sound absorption. The validity of using a simple room equation model to predict the cabin interior sound-pressure level for different fuselage and exterior sound field conditions is also presented. The room equation model is based on the sound power flow balance for the cabin space and utilizes the measured transmitted sound intensity data. The room equation model predictions were considered good enough to be used for preliminary acoustical design studies.

  16. GPS Sounding Rocket Developments

    NASA Technical Reports Server (NTRS)

    Bull, Barton

    1999-01-01

    Sounding rockets are suborbital launch vehicles capable of carrying scientific payloads several hundred miles in altitude. These missions return a variety of scientific data including; chemical makeup and physical processes taking place in the atmosphere, natural radiation surrounding the Earth, data on the Sun, stars, galaxies and many other phenomena. In addition, sounding rockets provide a reasonably economical means of conducting engineering tests for instruments and devices used on satellites and other spacecraft prior to their use in more expensive activities. This paper addresses the NASA Wallops Island history of GPS Sounding Rocket experience since 1994 and the development of highly accurate and useful system.

  17. GPS Sounding Rocket Developments

    NASA Technical Reports Server (NTRS)

    Bull, Barton

    1999-01-01

    Sounding rockets are suborbital launch vehicles capable of carrying scientific payloads several hundred miles in altitude. These missions return a variety of scientific data including; chemical makeup and physical processes taking place in the atmosphere, natural radiation surrounding the Earth, data on the Sun, stars, galaxies and many other phenomena. In addition, sounding rockets provide a reasonably economical means of conducting engineering tests for instruments and devices used on satellites and other spacecraft prior to their use in more expensive activities. This paper addresses the NASA Wallops Island history of GPS Sounding Rocket experience since 1994 and the development of highly accurate and useful system.

  18. Sounding the Sun

    DTIC Science & Technology

    1998-09-30

    Sounding the Sun Antony Fraser-Smith STAR Laboratory Stanford University Stanford, CA 94305 phone: (650) 723-3684 fax: (650) 723-9251 email...TITLE AND SUBTITLE Sounding the Sun 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK...systems. The objective of our “Sounding the sun ” experiment is to detect earth-directed CME’s by using existing earth-based HF (3- 30 MHz) radar systems

  19. Sound Visualization and Holography

    ERIC Educational Resources Information Center

    Kock, Winston E.

    1975-01-01

    Describes liquid surface holograms including their application to medicine. Discusses interference and diffraction phenomena using sound wave scanning techniques. Compares focussing by zone plate to holographic image development. (GH)

  20. Velocity of Sound

    ERIC Educational Resources Information Center

    Gillespie, A.

    1975-01-01

    Describes a method for the determination of the velocity of sound using a dual oscilloscope on which is displayed the sinusoidal input into a loudspeaker and the signal picked up by a microphone. (GS)

  1. Velocity of Sound

    ERIC Educational Resources Information Center

    Gillespie, A.

    1975-01-01

    Describes a method for the determination of the velocity of sound using a dual oscilloscope on which is displayed the sinusoidal input into a loudspeaker and the signal picked up by a microphone. (GS)

  2. The Sounds of Sentences: Differentiating the Influence of Physical Sound, Sound Imagery, and Linguistically Implied Sounds on Physical Sound Processing.

    PubMed

    Dudschig, Carolin; Mackenzie, Ian Grant; Strozyk, Jessica; Kaup, Barbara; Leuthold, Hartmut

    2016-10-01

    Both the imagery literature and grounded models of language comprehension emphasize the tight coupling of high-level cognitive processes, such as forming a mental image of something or language understanding, and low-level sensorimotor processes in the brain. In an electrophysiological study, imagery and language processes were directly compared and the sensory associations of processing linguistically implied sounds or imagined sounds were investigated. Participants read sentences describing auditory events (e.g., "The dog barks"), heard a physical (environmental) sound, or had to imagine such a sound. We examined the influence of the 3 sound conditions (linguistic, physical, imagery) on subsequent physical sound processing. Event-related potential (ERP) difference waveforms indicated that in all 3 conditions, prime compatibility influenced physical sound processing. The earliest compatibility effect was observed in the physical condition, starting in the 80-110 ms time interval with a negative maximum over occipital electrode sites. In contrast, the linguistic and the imagery condition elicited compatibility effects starting in the 180-220 ms time window with a maximum over central electrode sites. In line with the ERPs, the analysis of the oscillatory activity showed that compatibility influenced early theta and alpha band power changes in the physical, but not in the linguistic and imagery, condition. These dissociations were further confirmed by dipole localization results showing a clear separation between the source of the compatibility effect in the physical sound condition (superior temporal area) and the source of the compatibility effect triggered by the linguistically implied sounds or the imagined sounds (inferior temporal area). Implications for grounded models of language understanding are discussed.

  3. Orcas in Puget Sound

    DTIC Science & Technology

    2007-01-01

    de Fuca Strait, Puget Sound and the Strait of Georgia ) for a considerable time of the year, predominantly from early spring until late fall (Ford and...the south- ern part of Georgia Strait, Boundary Passage, the southern Gulf Islands and the eastern end of Juan de Fuca Strait (Heimlich- Boran 1988...Figure 2. Distribution of SRKW during September 2006 in Puget Sound and the southern Strait of Georgia (Advanced Satellite Productions, Orca Network

  4. Ecological sounds affect breath duration more than artificial sounds.

    PubMed

    Murgia, Mauro; Santoro, Ilaria; Tamburini, Giorgia; Prpic, Valter; Sors, Fabrizio; Galmonte, Alessandra; Agostini, Tiziano

    2016-01-01

    Previous research has demonstrated that auditory rhythms affect both movement and physiological functions. We hypothesized that the ecological sounds of human breathing can affect breathing more than artificial sounds of breathing, varying in tones for inspiration and expiration. To address this question, we monitored the breath duration of participants exposed to three conditions: (a) ecological sounds of breathing, (b) artificial sounds of breathing having equal temporal features as the ecological sounds, (c) no sounds (control). We found that participants' breath duration variability was reduced in the ecological sound condition, more than in the artificial sound condition. We suggest that ecological sounds captured the timing of breathing better than artificial sounds, guiding as a consequence participants' breathing. We interpreted our results according to the Theory of Event Coding, providing further support to its validity, and suggesting its possible extension in the domain of physiological functions which are both consciously and unconsciously controlled.

  5. Technology, Sound and Popular Music.

    ERIC Educational Resources Information Center

    Jones, Steve

    The ability to record sound is power over sound. Musicians, producers, recording engineers, and the popular music audience often refer to the sound of a recording as something distinct from the music it contains. Popular music is primarily mediated via electronics, via sound, and not by means of written notes. The ability to preserve or modify…

  6. Theoretical Modelling of Sound Radiation from Plate

    NASA Astrophysics Data System (ADS)

    Zaman, I.; Rozlan, S. A. M.; Yusoff, A.; Madlan, M. A.; Chan, S. W.

    2017-01-01

    Recently the development of aerospace, automotive and building industries demands the use of lightweight materials such as thin plates. However, the plates can possibly add to significant vibration and sound radiation, which eventually lead to increased noise in the community. So, in this study, the fundamental concept of sound pressure radiated from a simply-supported thin plate (SSP) was analyzed using the derivation of mathematical equations and numerical simulation of ANSYS®. The solution to mathematical equations of sound radiated from a SSP was visualized using MATLAB®. The responses of sound pressure level were measured at far field as well as near field in the frequency range of 0-200 Hz. Result shows that there are four resonance frequencies; 12 Hz, 60 Hz, 106 Hz and 158 Hz were identified which represented by the total number of the peaks in the frequency response function graph. The outcome also indicates that the mathematical derivation correlated well with the simulation model of ANSYS® in which the error found is less than 10%. It can be concluded that the obtained model is reliable and can be applied for further analysis such as to reduce noise emitted from a vibrating thin plate.

  7. Spectral Characteristics of Wake Vortex Sound During Roll-Up

    NASA Technical Reports Server (NTRS)

    Booth, Earl R., Jr. (Technical Monitor); Zhang, Yan; Wang, Frank Y.; Hardin, Jay C.

    2003-01-01

    This report presents an analysis of the sound spectra generated by a trailing aircraft vortex during its rolling-up process. The study demonstrates that a rolling-up vortex could produce low frequency (less than 100 Hz) sound with very high intensity (60 dB above threshold of human hearing) at a distance of 200 ft from the vortex core. The spectrum then drops o rapidly thereafter. A rigorous analytical approach has been adopted in this report to derive the spectrum of vortex sound. First, the sound pressure was solved from an alternative treatment of the Lighthill s acoustic analogy approach [1]. After the application of Green s function for free space, a tensor analysis was applied to permit the removal of the source term singularity of the wave equation in the far field. Consequently, the sound pressure is expressed in terms of the retarded time that indicates the time history and spacial distribution of the sound source. The Fourier transformation is then applied to the sound pressure to compute its spectrum. As a result, the Fourier transformation greatly simplifies the expression of the vortex sound pressure involving the retarded time, so that the numerical computation is applicable with ease for axisymmetric line vortices during the rolling-up process. The vortex model assumes that the vortex circulation is proportional to the time and the core radius is a constant. In addition, the velocity profile is assumed to be self-similar along the aircraft flight path, so that a benchmark vortex velocity profile can be devised to obtain a closed form solution, which is then used to validate the numerical calculations for other more realistic vortex profiles for which no closed form solutions are available. The study suggests that acoustic sensors operating at low frequency band could be profitably deployed for detecting the vortex sound during the rolling-up process.

  8. Sound modes in holographic superfluids

    SciTech Connect

    Herzog, Christopher P.; Yarom, Amos

    2009-11-15

    Superfluids support many different types of sound waves. We investigate the relation between the sound waves in a relativistic and a nonrelativistic superfluid by using hydrodynamics to calculate the various sound speeds. Then, using a particular holographic scalar gravity realization of a strongly interacting superfluid, we compute first, second, and fourth sound speeds as a function of the temperature. The relativistic low temperature results for second sound differ from Landau's well known prediction for the nonrelativistic, incompressible case.

  9. GPS Sounding Rocket Developments

    NASA Technical Reports Server (NTRS)

    Bull, Barton

    1999-01-01

    Sounding rockets are suborbital launch vehicles capable of carrying scientific payloads several hundred miles in altitude. These missions return a variety of scientific data including; chemical makeup and physical processes taking place In the atmosphere, natural radiation surrounding the Earth, data on the Sun, stars, galaxies and many other phenomena. In addition, sounding rockets provide a reasonably economical means of conducting engineering tests for instruments and devices used on satellites and other spacecraft prior to their use in more expensive activities. The NASA Sounding Rocket Program is managed by personnel from Goddard Space Flight Center Wallops Flight Facility (GSFC/WFF) in Virginia. Typically around thirty of these rockets are launched each year, either from established ranges at Wallops Island, Virginia, Poker Flat Research Range, Alaska; White Sands Missile Range, New Mexico or from Canada, Norway and Sweden. Many times launches are conducted from temporary launch ranges in remote parts of the world requi6ng considerable expense to transport and operate tracking radars. An inverse differential GPS system has been developed for Sounding Rocket. This paper addresses the NASA Wallops Island history of GPS Sounding Rocket experience since 1994 and the development of a high accurate and useful system.

  10. Meteor fireball sounds identified

    NASA Technical Reports Server (NTRS)

    Keay, Colin

    1992-01-01

    Sounds heard simultaneously with the flight of large meteor fireballs are electrical in origin. Confirmation that Extra/Very Low Frequency (ELF/VLF) electromagnetic radiation is produced by the fireball was obtained by Japanese researchers. Although the generation mechanism is not fully understood, studies of the Meteorite Observation and Recovery Project (MORP) and other fireball data indicate that interaction with the atmosphere is definitely responsible and the cut-off magnitude of -9 found for sustained electrophonic sounds is supported by theory. Brief bursts of ELF/VLF radiation may accompany flares or explosions of smaller fireballs, producing transient sounds near favorably placed observers. Laboratory studies show that mundane physical objects can respond to electrical excitation and produce audible sounds. Reports of electrophonic sounds should no longer be discarded. A catalog of over 300 reports relating to electrophonic phenomena associated with meteor fireballs, aurorae, and lightning was assembled. Many other reports have been cataloged in Russian. These may assist the full solution of the similar long-standing and contentious mystery of audible auroral displays.

  11. On categorizing sounds

    NASA Astrophysics Data System (ADS)

    Lockhead, Gregory R.

    1991-08-01

    Context is important when people judge sounds, or attributes of sounds, or other stimuli. It is shown how judgments depend on what sounds recently occurred (sequence effects), on how those sounds differ from one another (range effects), on the distribution of those differences (set effects), on what subjects are told about the situation (task effects), and on what subjects are told about their performance (feedback effects). Each of these factors determines the overall mean and variability of response times and response choices, which are the standard measures, when people judge attribute amounts. Trial-by-trial analysis of the data show these factors also determine performance on individual trials. Moreover, these momentary data cannot be predicted from the overall data. The opposite is not true; the averaged data can be predicted from the momentary details. These results are consistent with a model having two simple assumptions: successive sounds (not just their attributes) assimilate toward one another in memory, and judgments are based on comparisons of these remembered events. It is suggested that relations between attributes, rather than the magnitudes of the attributes themselves, are the basis for judgment.

  12. GPS Sounding Rocket Developments

    NASA Technical Reports Server (NTRS)

    Bull, Barton

    1999-01-01

    Sounding rockets are suborbital launch vehicles capable of carrying scientific payloads several hundred miles in altitude. These missions return a variety of scientific data including; chemical makeup and physical processes taking place In the atmosphere, natural radiation surrounding the Earth, data on the Sun, stars, galaxies and many other phenomena. In addition, sounding rockets provide a reasonably economical means of conducting engineering tests for instruments and devices used on satellites and other spacecraft prior to their use in more expensive activities. The NASA Sounding Rocket Program is managed by personnel from Goddard Space Flight Center Wallops Flight Facility (GSFC/WFF) in Virginia. Typically around thirty of these rockets are launched each year, either from established ranges at Wallops Island, Virginia, Poker Flat Research Range, Alaska; White Sands Missile Range, New Mexico or from Canada, Norway and Sweden. Many times launches are conducted from temporary launch ranges in remote parts of the world requi6ng considerable expense to transport and operate tracking radars. An inverse differential GPS system has been developed for Sounding Rocket. This paper addresses the NASA Wallops Island history of GPS Sounding Rocket experience since 1994 and the development of a high accurate and useful system.

  13. Yaw and spin effects on high intensity sound generation and on drag of training projectiles with ring cavities

    NASA Technical Reports Server (NTRS)

    Parthasarathy, S. P.; Cho, Y. I.; Kwack, E. Y.; Back, L. H.

    1986-01-01

    Projectiles containing axisymmetric ring cavities constitute aeroacoustic sources. These produce high intensity tones which are used for coding in the SAWE (Simulation of Area Weapons Effects) system. Experimental data obtained in a free jet facility are presented describing the effects of yaw, spin and geometric projectile parameters on sound pressure and drag. In general, the sound pressure decreases with increasing yaw angle whereas the drag increases. Spin tends to increase sound pressure levels because of a reduction in asymmetry of flow. Drag increases at zero yaw approximately as the 1.5 power of sound wavelength. A significant part of the drag increase appears to be due to energy loss by sound radiation.

  14. Yaw and spin effects on high intensity sound generation and on drag of training projectiles with ring cavities

    NASA Technical Reports Server (NTRS)

    Parthasarathy, S. P.; Cho, Y. I.; Kwack, E. Y.; Back, L. H.

    1986-01-01

    Projectiles containing axisymmetric ring cavities constitute aeroacoustic sources. These produce high intensity tones which are used for coding in the SAWE (Simulation of Area Weapons Effects) system. Experimental data obtained in a free jet facility are presented describing the effects of yaw, spin and geometric projectile parameters on sound pressure and drag. In general, the sound pressure decreases with increasing yaw angle whereas the drag increases. Spin tends to increase sound pressure levels because of a reduction in asymmetry of flow. Drag increases at zero yaw approximately as the 1.5 power of sound wavelength. A significant part of the drag increase appears to be due to energy loss by sound radiation.

  15. Sound quality prediction of vehicle interior noise and mathematical modeling using a back propagation neural network (BPNN) based on particle swarm optimization (PSO)

    NASA Astrophysics Data System (ADS)

    Zhang, Enlai; Hou, Liang; Shen, Chao; Shi, Yingliang; Zhang, Yaxiang

    2016-01-01

    To better solve the complex non-linear problem between the subjective sound quality evaluation results and objective psychoacoustics parameters, a method for the prediction of the sound quality is put forward by using a back propagation neural network (BPNN) based on particle swarm optimization (PSO), which is optimizing the initial weights and thresholds of BP network neurons through the PSO. In order to verify the effectiveness and accuracy of this approach, the noise signals of the B-Class vehicles from the idle speed to 120 km h-1 measured by the artificial head, are taken as a target. In addition, this paper describes a subjective evaluation experiment on the sound quality annoyance inside the vehicles through a grade evaluation method, by which the annoyance of each sample is obtained. With the use of Artemis software, the main objective psychoacoustic parameters of each noise sample are calculated. These parameters include loudness, sharpness, roughness, fluctuation, tonality, articulation index (AI) and A-weighted sound pressure level. Furthermore, three evaluation models with the same artificial neural network (ANN) structure are built: the standard BPNN model, the genetic algorithm-back-propagation neural network (GA-BPNN) model and the PSO-back-propagation neural network (PSO-BPNN) model. After the network training and the evaluation prediction on the three models’ network based on experimental data, it proves that the PSO-BPNN method can achieve convergence more quickly and improve the prediction accuracy of sound quality, which can further lay a foundation for the control of the sound quality inside vehicles.

  16. Active stereo sound localization.

    PubMed

    Reid, Greg L; Milios, Evangelos

    2003-01-01

    Estimating the direction of arrival of sound in three-dimensional space is typically performed by generalized time-delay processing on a set of signals from a fixed array of omnidirectional microphones. This requires specialized multichannel A/D hardware, and careful arrangement of the microphones into an array. This work is motivated by the desire to instead only use standard two-channel audio A/D hardware and portable equipment. To estimate direction of arrival of persistent sound, the position of the microphones is made variable by mounting them on one or more computer-controlled pan-and-tilt units. In this paper, we describe the signal processing and control algorithm of a device with two omnidirectional microphones on a fixed baseline and two rotational degrees of freedom. Experimental results with real data are reported with both impulsive and speech sounds in an untreated, normally reverberant indoor environment.

  17. Development of a Broadband Underwater Sound Projector

    DTIC Science & Technology

    1997-01-01

    classification systems use existing transducer designs, such as the tonpilz (piston) transducers . This type of design has been selected to provide a maximum...source level at 20 kHz with high efficiency and reliability as well as excellent directivity responses. The manufacturing of the tonpilz transducer is...an autonomous underwater vehicle (AUV). The transducer is resonant at 100 kHz but has been designed to deliver high sound pressure levels without

  18. Monaural Sound Localization Revisited

    NASA Technical Reports Server (NTRS)

    Wightman, Frederic L.; Kistler, Doris J.

    1997-01-01

    Research reported during the past few decades has revealed the importance for human sound localization of the so-called 'monaural spectral cues.' These cues are the result of the direction-dependent filtering of incoming sound waves accomplished by the pinnae. One point of view about how these cues are extracted places great emphasis on the spectrum of the received sound at each ear individually. This leads to the suggestion that an effective way of studying the influence of these cues is to measure the ability of listeners to localize sounds when one of their ears is plugged. Numerous studies have appeared using this monaural localization paradigm. Three experiments are described here which are intended to clarify the results of the previous monaural localization studies and provide new data on how monaural spectral cues might be processed. Virtual sound sources are used in the experiments in order to manipulate and control the stimuli independently at the two ears. Two of the experiments deal with the consequences of the incomplete monauralization that may have contaminated previous work. The results suggest that even very low sound levels in the occluded ear provide access to interaural localization cues. The presence of these cues complicates the interpretation of the results of nominally monaural localization studies. The third experiment concerns the role of prior knowledge of the source spectrum, which is required if monaural cues are to be useful. The results of this last experiment demonstrate that extraction of monaural spectral cues can be severely disrupted by trial-to-trial fluctuations in the source spectrum. The general conclusion of the experiments is that, while monaural spectral cues are important, the monaural localization paradigm may not be the most appropriate way to study their role.

  19. Effects of sounds of locomotion on speech perception

    PubMed Central

    Larsson, Matz; Ekström, Seth Reino; Ranjbar, Parivash

    2015-01-01

    Human locomotion typically creates noise, a possible consequence of which is the masking of sound signals originating in the surroundings. When walking side by side, people often subconsciously synchronize their steps. The neurophysiological and evolutionary background of this behavior is unclear. The present study investigated the potential of sound created by walking to mask perception of speech and compared the masking produced by walking in step with that produced by unsynchronized walking. The masking sound (footsteps on gravel) and the target sound (speech) were presented through the same speaker to 15 normal-hearing subjects. The original recorded walking sound was modified to mimic the sound of two individuals walking in pace or walking out of synchrony. The participants were instructed to adjust the sound level of the target sound until they could just comprehend the speech signal (“just follow conversation” or JFC level) when presented simultaneously with synchronized or unsynchronized walking sound at 40 dBA, 50 dBA, 60 dBA, or 70 dBA. Synchronized walking sounds produced slightly less masking of speech than did unsynchronized sound. The median JFC threshold in the synchronized condition was 38.5 dBA, while the corresponding value for the unsynchronized condition was 41.2 dBA. Combined results at all sound pressure levels showed an improvement in the signal-to-noise ratio (SNR) for synchronized footsteps; the median difference was 2.7 dB and the mean difference was 1.2 dB [P < 0.001, repeated-measures analysis of variance (RM-ANOVA)]. The difference was significant for masker levels of 50 dBA and 60 dBA, but not for 40 dBA or 70 dBA. This study provides evidence that synchronized walking may reduce the masking potential of footsteps. PMID:26168953

  20. Eliciting Sound Memories.

    PubMed

    Harris, Anna

    2015-11-01

    Sensory experiences are often considered triggers of memory, most famously a little French cake dipped in lime blossom tea. Sense memory can also be evoked in public history research through techniques of elicitation. In this article I reflect on different social science methods for eliciting sound memories such as the use of sonic prompts, emplaced interviewing, and sound walks. I include examples from my research on medical listening. The article considers the relevance of this work for the conduct of oral histories, arguing that such methods "break the frame," allowing room for collaborative research connections and insights into the otherwise unarticulatable.

  1. The Imagery of Sound

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Automated Analysis Corporation's COMET is a suite of acoustic analysis software for advanced noise prediction. It analyzes the origin, radiation, and scattering of noise, and supplies information on how to achieve noise reduction and improve sound characteristics. COMET's Structural Acoustic Foam Engineering (SAFE) module extends the sound field analysis capability of foam and other materials. SAFE shows how noise travels while airborne, how it travels within a structure, and how these media interact to affect other aspects of the transmission of noise. The COMET software reduces design time and expense while optimizing a final product's acoustical performance. COMET was developed through SBIR funding and Langley Research Center for Automated Analysis Corporation.

  2. Tracking speech sound acquisition.

    PubMed

    Powell, Thomas W

    2011-11-01

    This article describes a procedure to aid in the clinical appraisal of child speech. The approach, based on the work by Dinnsen, Chin, Elbert, and Powell (1990; Some constraints on functionally disordered phonologies: Phonetic inventories and phonotactics. Journal of Speech and Hearing Research, 33, 28-37), uses a railway idiom to track gains in the complexity of speech sound production. A clinical case study is reviewed to illustrate application of the procedure. The procedure is intended to facilitate application of an evidence-based procedure to the clinical management of developmental speech sound disorders.

  3. Frequency Dynamics of the First Heart Sound

    NASA Astrophysics Data System (ADS)

    Wood, John Charles

    Cardiac auscultation is a fundamental clinical tool but first heart sound origins and significance remain controversial. Previous clinical studies have implicated resonant vibrations of both the myocardium and the valves. Accordingly, the goals of this thesis were threefold, (1) to characterize the frequency dynamics of the first heart sound, (2) to determine the relative contribution of the myocardium and the valves in determining first heart sound frequency, and (3) to develop new tools for non-stationary signal analysis. A resonant origin for first heart sound generation was tested through two studies in an open-chest canine preparation. Heart sounds were recorded using ultralight acceleration transducers cemented directly to the epicardium. The first heart sound was observed to be non-stationary and multicomponent. The most dominant feature was a powerful, rapidly-rising frequency component that preceded mitral valve closure. Two broadband components were observed; the first coincided with mitral valve closure while the second significantly preceded aortic valve opening. The spatial frequency of left ventricular vibrations was both high and non-stationary which indicated that the left ventricle was not vibrating passively in response to intracardiac pressure fluctuations but suggested instead that the first heart sound is a propagating transient. In the second study, regional myocardial ischemia was induced by left coronary circumflex arterial occlusion. Acceleration transducers were placed on the ischemic and non-ischemic myocardium to determine whether ischemia produced local or global changes in first heart sound amplitude and frequency. The two zones exhibited disparate amplitude and frequency behavior indicating that the first heart sound is not a resonant phenomenon. To objectively quantify the presence and orientation of signal components, Radon transformation of the time -frequency plane was performed and found to have considerable potential for pattern

  4. Relating the radiated piano sound field to the vibrational modes of the soundboard

    NASA Astrophysics Data System (ADS)

    Hansen, Uwe J.; Bork, Ingolf; Rossing, Thomas D.

    2003-10-01

    The sound field near a piano sound board is determined by moving a microphone over a grid of points above and below the sound board as well as in a plane in front of the piano using the experimental techniques of modal analysis with soundboard excitation at a bridge point by a swept sine signal. Since the standard modal analysis signal processing technique relies on tracking phase relations between excitation and response, it is possible to relate the sound field in terms of the vibrating structure which radiated it. Animations of sound board motion and sound field pressure variations are shown for the lowest four modes. It is noted that in all modes the locations of maximal excursion correlate with the sound pressure maxima or minima, respectively.

  5. Annoyance caused by the sounds of a magnetic levitation train.

    PubMed

    Vos, Joos

    2004-04-01

    In a laboratory study, the annoyance caused by the passby sounds from a magnetic levitation (maglev) train was investigated. The listeners were presented with various sound fragments. The task of the listeners was to respond after each presentation to the question: "How annoying would you find the sound in the preceding period if you were exposed to it at home on a regular basis?" The independent variables were (a) the driving speed of the maglev train (varying from 100 to 400 km/h), (b) the outdoor A-weighted sound exposure level (ASEL) of the passbys (varying from 65 to 90 dB), and (c) the simulated outdoor-to-indoor reduction in sound level (windows open or windows closed). As references to the passby sounds from the maglev train (type Transrapid 08), sounds from road traffic (passenger cars and trucks) and more conventional railway (intercity trains) were included for rating also. Four important results were obtained. Provided that the outdoor ASELs were the same, (1) the annoyance was independent of the driving speed of the maglev train, (2) the annoyance caused by the maglev train was considerably higher than that caused by the intercity train, (3) the annoyance caused by the maglev train was hardly different from that caused by road traffic, and (4) the results (1)-(3) held true both for open or closed windows. On the basis of the present results, it might be expected that the sounds are equally annoying if the ASELs of the maglev-train passbys are at least 5 dB lower than those of the intercity train passbys. Consequently, the results of the present experiment do not support application of a railway bonus to the maglev-train sounds.

  6. Exercise Clothing for Children in a Weight-Management Program

    ERIC Educational Resources Information Center

    Carroll, Kate; Alexander, Marina; Spencer, Virginia

    2007-01-01

    This study investigated whether clothing can be perceived as a form of encouragement for success in a weight management exercise program. A small (n = 30) sample of children and parents, enrolled in a weight-management exercise program, responded to a survey instrument that included questions regarding fit and comfort of the clothing children wore…

  7. Exercise Clothing for Children in a Weight-Management Program

    ERIC Educational Resources Information Center

    Carroll, Kate; Alexander, Marina; Spencer, Virginia

    2007-01-01

    This study investigated whether clothing can be perceived as a form of encouragement for success in a weight management exercise program. A small (n = 30) sample of children and parents, enrolled in a weight-management exercise program, responded to a survey instrument that included questions regarding fit and comfort of the clothing children wore…

  8. The effect of spatial distribution on the annoyance caused by simultaneous sounds

    NASA Astrophysics Data System (ADS)

    Vos, Joos; Bronkhorst, Adelbert W.; Fedtke, Thomas

    2004-05-01

    A considerable part of the population is exposed to simultaneous and/or successive environmental sounds from different sources. In many cases, these sources are different with respect to their locations also. In a laboratory study, it was investigated whether the annoyance caused by the multiple sounds is affected by the spatial distribution of the sources. There were four independent variables: (1) sound category (stationary or moving), (2) sound type (stationary: lawn-mower, leaf-blower, and chain saw; moving: road traffic, railway, and motorbike), (3) spatial location (left, right, and combinations), and (4) A-weighted sound exposure level (ASEL of single sources equal to 50, 60, or 70 dB). In addition to the individual sounds in isolation, various combinations of two or three different sources within each sound category and sound level were presented for rating. The annoyance was mainly determined by sound level and sound source type. In most cases there were neither significant main effects of spatial distribution nor significant interaction effects between spatial distribution and the other variables. It was concluded that for rating the spatially distrib- uted sounds investigated, the noise dose can simply be determined by a summation of the levels for the left and right channels. [Work supported by CEU.

  9. Exploring Sound with Insects

    ERIC Educational Resources Information Center

    Robertson, Laura; Meyer, John R.

    2010-01-01

    Differences in insect morphology and movement during singing provide a fascinating opportunity for students to investigate insects while learning about the characteristics of sound. In the activities described here, students use a free online computer software program to explore the songs of the major singing insects and experiment with making…

  10. Making Sense of Sound

    ERIC Educational Resources Information Center

    Menon, Deepika; Lankford, Deanna

    2016-01-01

    From the earliest days of their lives, children are exposed to all kinds of sound, from soft, comforting voices to the frightening rumble of thunder. Consequently, children develop their own naïve explanations largely based upon their experiences with phenomena encountered every day. When new information does not support existing conceptions,…

  11. Creative Sound Dramatics

    ERIC Educational Resources Information Center

    Hendrix, Rebecca; Eick, Charles

    2014-01-01

    Sound propagation is not easy for children to understand because of its abstract nature, often best represented by models such as wave drawings and particle dots. Teachers Rebecca Hendrix and Charles Eick wondered how science inquiry, when combined with an unlikely discipline like drama, could produce a better understanding among their…

  12. Sound and Sense.

    ERIC Educational Resources Information Center

    Fleischman, Paul

    1986-01-01

    Claims that in metrical prose, rhythm can convey sense or express and underline what a writer is saying, and sound can be exploited to add a strong aural element that provides pleasure to the ears over and above the pleasure given by the sense of story. (SRT)

  13. Exploring Sound with Insects

    ERIC Educational Resources Information Center

    Robertson, Laura; Meyer, John R.

    2010-01-01

    Differences in insect morphology and movement during singing provide a fascinating opportunity for students to investigate insects while learning about the characteristics of sound. In the activities described here, students use a free online computer software program to explore the songs of the major singing insects and experiment with making…

  14. Creative Sound Dramatics

    ERIC Educational Resources Information Center

    Hendrix, Rebecca; Eick, Charles

    2014-01-01

    Sound propagation is not easy for children to understand because of its abstract nature, often best represented by models such as wave drawings and particle dots. Teachers Rebecca Hendrix and Charles Eick wondered how science inquiry, when combined with an unlikely discipline like drama, could produce a better understanding among their…

  15. Making Sense of Sound

    ERIC Educational Resources Information Center

    Menon, Deepika; Lankford, Deanna

    2016-01-01

    From the earliest days of their lives, children are exposed to all kinds of sound, from soft, comforting voices to the frightening rumble of thunder. Consequently, children develop their own naïve explanations largely based upon their experiences with phenomena encountered every day. When new information does not support existing conceptions,…

  16. Sight/Sound System.

    ERIC Educational Resources Information Center

    Cooper, Richard

    This guide explains the purpose, components, and use of the Sight/Sound System, which is an alternative reading instruction approach designed to meet the individual needs of learners of all ages who have poor decoding skills. Described in the first section are the ways in which the system works to accomplish the following goals: develop…

  17. Sound separation probes for flowing duct noise measurements. [jet engine diagnostics

    NASA Technical Reports Server (NTRS)

    Moore, M. T.

    1977-01-01

    In order to understand the propagation of broadband sound from a device such as a jet engine, it is necessary to make fluctuating pressure measurements in the ducted airstream. However, in a flowing duct, fluctuating pressure energy can be due to both turbulence and sound travelling in the duct. By using the principal that sound waves and turbulent flow pressure perturbations travel at different velocities, a probe has been developed that provides the data necessary to separate the energy due to sound from that due to turbulence. A mini-computer based FFT analysis of the probe measurements provides the overall level of the broadband sound in the duct as well as the spectral distribution of the sound energy.

  18. Quality Sound: A Handbook for Additional Duty Sound Men.

    DTIC Science & Technology

    1986-04-01

    and identdfy by block number) Contemporary musical performance by Air Force bands necessitates heavy reliance on amplified sound . Operation of sound ...bands with no support slots authorized. Consequently, bandsmer perform non- musical functions as additional duties. The function of sound man, therefore...arena, doing without is not a viable option. The performance media today center around light and sound . Most contemporary music is vocal in nature

  19. The shock Hugoniot of 316 ss and sound velocity measurements

    SciTech Connect

    Hixson, R.S.; McQueen, R.G.; Fritz, J.N.

    1993-01-01

    Type 316 stainless steel has been characterized for its high-pressure, shock-wave response. Measurements have been made of shock-wave and particle velocity, and of sound velocity. Our preliminary results for shock and particle velocity have been combined with previously unpublished results, and an overall fit made. Sound velocity results show a discontinuity that is attributed to shock-induced melting.

  20. The shock Hugoniot of 316 ss and sound velocity measurements

    SciTech Connect

    Hixson, R.S.; McQueen, R.G.; Fritz, J.N.

    1993-07-01

    Type 316 stainless steel has been characterized for its high-pressure, shock-wave response. Measurements have been made of shock-wave and particle velocity, and of sound velocity. Our preliminary results for shock and particle velocity have been combined with previously unpublished results, and an overall fit made. Sound velocity results show a discontinuity that is attributed to shock-induced melting.

  1. Explanatory model for sound amplification in a stethoscope

    NASA Astrophysics Data System (ADS)

    Eshach, H.; Volfson, A.

    2015-01-01

    In the present paper we suggest an original physical explanatory model that explains the mechanism of the sound amplification process in a stethoscope. We discuss the amplification of a single pulse, a continuous wave of certain frequency, and finally we address the resonant frequencies. It is our belief that this model may provide students with opportunities to not only better understand the amplification mechanism of a stethoscope, but also to strengthen their understanding of sound, pressure, waves, resonance modes, etc.

  2. Blood Pressure Checker

    NASA Technical Reports Server (NTRS)

    1979-01-01

    An estimated 30 million people in the United States have high blood pressure, or hypertension. But a great many of them are unaware of it because hypertension, in its initial stages, displays no symptoms. Thus, the simply-operated blood pressure checking devices now widely located in public places are useful health aids. The one pictured above, called -Medimax 30, is a direct spinoff from NASA technology developed to monitor astronauts in space. For manned space flights, NASA wanted a compact, highly-reliable, extremely accurate method of checking astronauts' blood pressure without the need for a physician's interpretive skill. NASA's Johnson Space Center and Technology, Inc., a contractor, developed an electronic sound processor that automatically analyzes blood flow sounds to get both systolic (contracting arteries) and diastolic (expanding arteries) blood pressure measurements. NASA granted a patent license for this technology to Advanced Life Sciences, Inc., New York City, manufacturers of Medimax 30.

  3. Disturbing effects of low frequency sound immissions and vibrations in residential buildings.

    PubMed

    Findeis, H; Peters, E

    2004-01-01

    Noise immissions with predominant low frequency sound components may exert considerably disturbing effects in dwellings. This applies in particular to sounds which are excitated by transmission of structure-borne noise, and to low frequency sounds emitted by ventilators. Exposed persons usually declare such immissions as being "intolerable" even at very low A-weighted sound levels. If mechanical vibrations in the frequency range below 20 Hz (ground-borne vibrations) affect dwelling rooms, the annoying effects are perceived only by a small portion of exposed individuals as a physical effect. For the most part the immissions are observed as vibratory effects on the building and on objects inside the dwelling. The disturbing effects of vibration frequencies above 20 Hz (structure-borne sound) are determined by the airborne sound field generated inside a particular room and its given surface and extension.

  4. Sound source localization by the plainfin midshipman fish, Porichthys notatus.

    PubMed

    Zeddies, David G; Fay, Richard R; Alderks, Peter W; Shaub, Kiel S; Sisneros, Joseph A

    2010-05-01

    The aim of this study was to use plainfin midshipman fish (Porichthys notatus) as a general model to explore how fishes localize an underwater sound source in the relatively simple geometry of a monopole sound field. The robust phonotaxic responses displayed by gravid females toward a monopole sound projector (J-9) broadcasting a low-frequency (90 Hz) tone similar to the fundamental frequency of the male's advertisement call were examined. The projector's sound field was mapped at 5 cm resolution azimuth using an eight-hydrophone array. Acoustic pressure was measured with the array and acoustic particle motion was calculated from pressure gradients between hydrophones. The response pathways of the fish were analyzed from video recordings and compared to the sound field. Gravid females at initial release were directed toward the sound source, and the majority (73%) swam to the playback projector with straight to slightly curved tracks in the direction of the source and in line with local particle motion vectors. In contrast, the initial direction of the control (sound-off) group did not differ from random. This paper reports on a comparison of fish localization behavior with directional cues available in the form of local particle motion vectors.

  5. A method for characterizing aerodynamic sound sources in turbomachines

    NASA Astrophysics Data System (ADS)

    Mongeau, L.; Thompson, D. E.; Mclaughlin, D. K.

    1995-03-01

    A method based on Weidemann's acoustic similarity laws [1] was used to investigate the aerodynamic sound generated by a partially ducted centrifugal pump rotor. The primary objective of the method was to determine the spectral characteristics of the sound source by isolating the effects of acoustic phenomena such as duct resonances or sound reflections. Pump-radiated sound pressure spectra were measured for different impeller rotational speeds, keeping the operating condition constant. The spectra, assumed to be expressed as the product of a source spectral distribution function and an acoustic frequency response function, were then decomposed into a product form following a computer-implemented algorithm. The method was successful in accurately determining the spectral distribution of the broadband aerodynamic noise generating mechanisms involved and that of the acoustic frequency response of the system. The absolute levels of the source function and the acoustic function were established by assuming that, over a limited low frequency range, the average gain of the frequency response function is unity so that comparisons between different pump operating conditions could be made. The source spectral distribution was found to be independent of the microphone location and the acoustic loading. When applicable, this method therefore allows the characterization of aerodynamic sound sources by measuring ordinary sound pressure spectra, at any one point around the source, without having to isolate the source from the system. The source characterization method was instrumental in the study of sound generation by rotating stall presented in a previous publication [2].

  6. Active control of excessive sound emission on a mobile device.

    PubMed

    Jeon, Se-Woon; Youn, Dae Hee; Park, Young-cheol; Lee, Gun-Woo

    2015-04-01

    During a phone conversation, loud vocal emission from the far-end to the near-end space can disturb nearby people. In this paper, the possibility of actively controlling such unwanted sound emission using a control source placed on the mobile device is investigated. Two different approaches are tested: Global control, minimizing the potential energy measured along a volumetric space surface, and local control, minimizing the squared sound pressure at a discrete point on the phone. From the test results, both approaches can reduce the unwanted sound emission by more than 6 dB in the frequency range up to 2 kHz.

  7. Radiometric sounding system

    SciTech Connect

    Whiteman, C.D.; Anderson, G.A.; Alzheimer, J.M.; Shaw, W.J.

    1995-04-01

    Vertical profiles of solar and terrestrial radiative fluxes are key research needs for global climate change research. These fluxes are expected to change as radiatively active trace gases are emitted to the earth`s atmosphere as a consequence of energy production and industrial and other human activities. Models suggest that changes in the concentration of such gases will lead to radiative flux divergences that will produce global warming of the earth`s atmosphere. Direct measurements of the vertical variation of solar and terrestrial radiative fluxes that lead to these flux divergences have been largely unavailable because of the expense of making such measurements from airplanes. These measurements are needed to improve existing atmospheric radiative transfer models, especially under the cloudy conditions where the models have not been adequately tested. A tethered-balloon-borne Radiometric Sounding System has been developed at Pacific Northwest Laboratory to provide an inexpensive means of making routine vertical soundings of radiative fluxes in the earth`s atmospheric boundary layer to altitudes up to 1500 m above ground level. Such vertical soundings would supplement measurements being made from aircraft and towers. The key technical challenge in the design of the Radiometric Sounding System is to develop a means of keeping the radiometers horizontal while the balloon ascends and descends in a turbulent atmospheric environment. This problem has been addressed by stabilizing a triangular radiometer-carrying platform that is carried on the tetherline of a balloon sounding system. The platform, carried 30 m or more below the balloon to reduce the balloon`s effect on the radiometric measurements, is leveled by two automatic control loops that activate motors, gears and pulleys when the platform is off-level. The sensitivity of the automatic control loops to oscillatory motions of various frequencies and amplitudes can be adjusted using filters.

  8. About sound mufflers sound-absorbing panels aircraft engine

    NASA Astrophysics Data System (ADS)

    Dudarev, A. S.; Bulbovich, R. V.; Svirshchev, V. I.

    2016-10-01

    The article provides a formula for calculating the frequency of sound absorbed panel with a perforated wall. And although the sound absorbing structure is a set of resonators Helmholtz, not individual resonators should be considered in acoustic calculations, and all the perforated wall panel. The analysis, showing how the parameters affect the size and sound-absorbing structures in the absorption rate.

  9. Sounds of the Ancient Universe

    NASA Image and Video Library

    2013-03-21

    Tones represents sound waves that traveled through the early universe, and were later heard by ESA Planck space telescope. The primordial sound waves have been translated into frequencies we can hear.

  10. Modeling the Transmission of Sound.

    ERIC Educational Resources Information Center

    Palmer, David H.

    2003-01-01

    Introduces a functional model of sound transmission through solids and gases. Describes procedures of an activity to model how sound travels faster through solid materials than gases. Use dominoes to represent the particles of solids and gases. (KHR)

  11. Analytical study of the horizontal ducting of sound by an oceanic front over a slope.

    PubMed

    Lin, Ying-Tsong; Lynch, James F

    2012-01-01

    The horizontal ducting of sound by an oceanic temperature front over a sloping bottom is studied with an idealized wedge model consisting of a lateral interface across the slope. The water outside the frontal interface has higher temperature, hence faster sound speed, and it will produce inshore reflection/refraction of the sound. Combining the offshore refraction caused by the sloping bottom, propagating sound can be ducted along the front. An analytical solution to the sound pressure field in the idealized model is derived, and an example is presented to demonstrate and discuss the ducting effect.

  12. Sound exposure during outdoor music festivals.

    PubMed

    Tronstad, Tron V; Gelderblom, Femke B

    2016-01-01

    Most countries have guidelines to regulate sound exposure at concerts and music festivals. These guidelines limit the allowed sound pressure levels and the concert/festival's duration. In Norway, where there is such a guideline, it is up to the local authorities to impose the regulations. The need to prevent hearing-loss among festival participants is self-explanatory, but knowledge of the actual dose received by visitors is extremely scarce. This study looks at two Norwegian music festivals where only one was regulated by the Norwegian guideline for concert and music festivals. At each festival the sound exposure of four participants was monitored with noise dose meters. This study compared the exposures experienced at the two festivals, and tested them against the Norwegian guideline and the World Health Organization's recommendations. Sound levels during the concerts were higher at the festival not regulated by any guideline, and levels there exceeded both the national and the Worlds Health Organization's recommendations. The results also show that front-of-house measurements reliably predict participant exposure.

  13. Sound Exposure During Outdoor Music Festivals

    PubMed Central

    Tronstad, Tron V.; Gelderblom, Femke B.

    2016-01-01

    Most countries have guidelines to regulate sound exposure at concerts and music festivals. These guidelines limit the allowed sound pressure levels and the concert/festival's duration. In Norway, where there is such a guideline, it is up to the local authorities to impose the regulations. The need to prevent hearing-loss among festival participants is self-explanatory, but knowledge of the actual dose received by visitors is extremely scarce. This study looks at two Norwegian music festivals where only one was regulated by the Norwegian guideline for concert and music festivals. At each festival the sound exposure of four participants was monitored with noise dose meters. This study compared the exposures experienced at the two festivals, and tested them against the Norwegian guideline and the World Health Organization's recommendations. Sound levels during the concerts were higher at the festival not regulated by any guideline, and levels there exceeded both the national and the Worlds Health Organization's recommendations. The results also show that front-of-house measurements reliably predict participant exposure. PMID:27569410

  14. THE SOUND PATTERN OF ENGLISH.

    ERIC Educational Resources Information Center

    CHOMSKY, NOAM; HALLE, MORRIS

    "THE SOUND PATTERN OF ENGLISH" PRESENTS A THEORY OF SOUND STRUCTURE AND A DETAILED ANALYSIS OF THE SOUND STRUCTURE OF ENGLISH WITHIN THE FRAMEWORK OF GENERATIVE GRAMMAR. IN THE PREFACE TO THIS BOOK THE AUTHORS STATE THAT THEIR "WORK IN THIS AREA HAS REACHED A POINT WHERE THE GENERAL OUTLINES AND MAJOR THEORETICAL PRINCIPLES ARE FAIRLY CLEAR" AND…

  15. Just How Does Sound Wave?

    ERIC Educational Resources Information Center

    Shipman, Bob

    2006-01-01

    When children first hear the term "sound wave" perhaps they might associate it with the way a hand waves or perhaps the squiggly line image on a television monitor when sound recordings are being made. Research suggests that children tend to think sound somehow travels as a discrete package, a fast-moving invisible thing, and not something that…

  16. Just How Does Sound Wave?

    ERIC Educational Resources Information Center

    Shipman, Bob

    2006-01-01

    When children first hear the term "sound wave" perhaps they might associate it with the way a hand waves or perhaps the squiggly line image on a television monitor when sound recordings are being made. Research suggests that children tend to think sound somehow travels as a discrete package, a fast-moving invisible thing, and not something that…

  17. Sounds Alive: A Noise Workbook.

    ERIC Educational Resources Information Center

    Dickman, Donna McCord

    Sarah Screech, Danny Decibel, Sweetie Sound and Neil Noisy describe their experiences in the world of sound and noise to elementary students. Presented are their reports, games and charts which address sound measurement, the effects of noise on people, methods of noise control, and related areas. The workbook is intended to stimulate students'…

  18. Data sonification and sound visualization.

    SciTech Connect

    Kaper, H. G.; Tipei, S.; Wiebel, E.; Mathematics and Computer Science; Univ. of Illinois

    1999-07-01

    Sound can help us explore and analyze complex data sets in scientific computing. The authors describe a digital instrument for additive sound synthesis (Diass) and a program to visualize sounds in a virtual reality environment (M4Cave). Both are part of a comprehensive music composition environment that includes additional software for computer-assisted composition and automatic music notation.

  19. Environmentally sound manufacturing

    NASA Technical Reports Server (NTRS)

    Caddy, Larry A.; Bowman, Ross; Richards, Rex A.

    1994-01-01

    The NASA/Thiokol/industry team has developed and started implementation of an environmentally sound manufacturing plan for the continued production of solid rocket motors. They have worked with other industry representatives and the U.S. Environmental Protection Agency to prepare a comprehensive plan to eliminate all ozone depleting chemicals from manufacturing processes and to reduce the use of other hazardous materials used to produce the space shuttle reusable solid rocket motors. The team used a classical approach for problem solving combined with a creative synthesis of new approaches to attack this problem. As our ability to gather data on the state of the Earth's environmental health increases, environmentally sound manufacturing must become an integral part of the business decision making process.

  20. Synchronization of Sound Sources

    NASA Astrophysics Data System (ADS)

    Abel, Markus; Ahnert, Karsten; Bergweiler, Steffen

    2009-09-01

    Sound generation and interaction are highly complex, nonlinear, and self-organized. Nearly 150 years ago Rayleigh raised the following problem: two nearby organ pipes of different fundamental frequencies sound together almost inaudibly with identical pitch. This effect is now understood qualitatively by modern synchronization theory M. Abel et al. [J. Acoust. Soc. Am. 119, 2467 (2006)JASMAN0001-496610.1121/1.2170441]. For a detailed investigation, we substituted one pipe by an electric speaker. We observe that even minute driving signals force the pipe to synchronization, thus yielding three decades of synchronization—the largest range ever measured to our knowledge. Furthermore, a mutual silencing of the pipe is found, which can be explained by self-organized oscillations, of use for novel methods of noise abatement. Finally, we develop a reconstruction method which yields a perfect quantitative match of experiment and theory.

  1. Environmentally sound manufacturing

    NASA Astrophysics Data System (ADS)

    Caddy, Larry A.; Bowman, Ross; Richards, Rex A.

    The NASA/Thiokol/industry team has developed and started implementation of an environmentally sound manufacturing plan for the continued production of solid rocket motors. They have worked with other industry representatives and the U.S. Environmental Protection Agency to prepare a comprehensive plan to eliminate all ozone depleting chemicals from manufacturing processes and to reduce the use of other hazardous materials used to produce the space shuttle reusable solid rocket motors. The team used a classical approach for problem solving combined with a creative synthesis of new approaches to attack this problem. As our ability to gather data on the state of the Earth's environmental health increases, environmentally sound manufacturing must become an integral part of the business decision making process.

  2. Wood for sound.

    PubMed

    Wegst, Ulrike G K

    2006-10-01

    The unique mechanical and acoustical properties of wood and its aesthetic appeal still make it the material of choice for musical instruments and the interior of concert halls. Worldwide, several hundred wood species are available for making wind, string, or percussion instruments. Over generations, first by trial and error and more recently by scientific approach, the most appropriate species were found for each instrument and application. Using material property charts on which acoustic properties such as the speed of sound, the characteristic impedance, the sound radiation coefficient, and the loss coefficient are plotted against one another for woods. We analyze and explain why spruce is the preferred choice for soundboards, why tropical species are favored for xylophone bars and woodwind instruments, why violinists still prefer pernambuco over other species as a bow material, and why hornbeam and birch are used in piano actions.

  3. Experimental study on HVAC sound parameters

    NASA Astrophysics Data System (ADS)

    Bujoreanu, C.; Benchea, M.

    2016-08-01

    HVAC system represent major source of buildings internal noise and therefore they are designed to provide a human acoustic comfort besides the thermal and air quality requirements. The paper experimentally investigates three types of commercial air handler units (AHU) with different ducts cross-section sizes and inlet-outlet configuration. The measurements are performed in an anechoic room. The measurements are carried out at different fan's speeds, ranging the power-charge from 30-100% while the duct air flow is slowly adjusted from full open to full closed, between 0-500 Pa. The sound pressure levels of the radiant units are rated using NR curves. Also, the supply and the outdoor ducts sound levels are compared in order to point the frequencies where the noise must be reduced. Third-octave band analysis of random noise of an air handling unit from a HVAC system is realized, using measurement procedures that agrees the requirements of the ISO 3744:2011 and ISO 5136:2010 standards. The comparatively results highlight the effects of the geometry, air flow pressure and power-charging dependencies upon the sound level. This is the start for a noise reduction strategy.

  4. Non-contact sound speed measurement by optical probing of beam deflection due to sound wave.

    PubMed

    Jung, Sung Soo; Kim, Yong Tae; Pu, Yu Cheon; Kim, Min Gon; Kim, Ho Chul

    2006-01-01

    We report a non-contact and non-invasive method of sound speed measurement by optical probing of deflected laser beam due to normally incident degenerated shock wave. In this study the shock wave from an exploding wire was degenerated to an ordinary sound wave at the distance exceeding 0.23 m. Temporal resolution of the deflected beam signal was improved by passing through an adequate electronic high-pass filter, as a result we obtained a better temporal resolution than that of the acoustic pressure detection by PZT transducer in terms of rising time. The spatial resolution was improved by passing the refracted beam signal into the edge of focusing lens to make a larger deflection angle. Sound speed was calculated by monitoring the time of flight of transient deflected signal at the predetermined position. Sound speed has been measured in air, distilled water and acryl, agreed well with the published values. The sound speed measured in the solution of glycerin, magnesium sulfate (MgSO4), and dimethylformamide with various mole fractions also agrees within 3% of relative error with those measured in the present work by ultrasonic pulse echo method. The results suggest that the method proposed is to be reliable and reproducible.

  5. Sound categories or phonemes?

    PubMed

    Redford, Melissa A

    2017-02-01

    Vihman emphasizes the importance of early word production to the emergence of phonological knowledge. This emphasis, consistent with the generative function of phonology, provides insight into the concurrent representation of phonemes and words. At the same time, Vihman's focus on phonology leads her to possibly overstate the influence of early word acquisition on the emergence of sound categories that are probably purely phonetic in nature at the outset of learning.

  6. The Aries sounding rocket

    NASA Astrophysics Data System (ADS)

    Dooling, D.

    1980-02-01

    A family of sounding rockets called Aries, using the motors from obsolete Minuteman ICBMs, is described. Payloads for Aries range from 1,500 to 3,500 lb (with a payload diameter of 44 in.) and include various instruments (magnetospheric tracers, X-ray and extreme ultraviolet astronomy and a large X-ray telescope). Prospects for future launching of a two and even three-stage Aries are discussed.

  7. Marine Animal SOUND Database

    DTIC Science & Technology

    1991-08-01

    ontogeny of learned signals) in selected species (sperm whales , finbacks, bowheads, bottlenose dolphins, etc). For example, our 1954-1968 sperm whale ...recordings led to specific studies of their activities, which in turn opened the way to work focused on coda signals produced by these whales , and...then to analyses of distinctions between codas from individuals and those shared by the members a particular whale group. 8--8- Marine Animal SOUND

  8. 46 CFR 7.20 - Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and easterly entrance to Long Island Sound, NY. 7.20 Section 7.20... Atlantic Coast § 7.20 Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block...

  9. 46 CFR 7.20 - Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and easterly entrance to Long Island Sound, NY. 7.20 Section 7.20... Atlantic Coast § 7.20 Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block...

  10. 46 CFR 7.20 - Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and easterly entrance to Long Island Sound, NY. 7.20 Section 7.20... Atlantic Coast § 7.20 Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block...

  11. 46 CFR 7.20 - Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and easterly entrance to Long Island Sound, NY. 7.20 Section 7.20... Atlantic Coast § 7.20 Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block...

  12. 46 CFR 7.20 - Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and easterly entrance to Long Island Sound, NY. 7.20 Section 7.20... Atlantic Coast § 7.20 Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block...

  13. The Sounds of Space

    NASA Astrophysics Data System (ADS)

    Gurnett, Donald

    2009-11-01

    The popular concept of space is that it is a vacuum, with nothing of interest between the stars, planets, moons and other astronomical objects. In fact most of space is permeated by plasma, sometimes quite dense, as in the solar corona and planetary ionospheres, and sometimes quite tenuous, as is in planetary radiation belts. Even less well known is that these space plasmas support and produce an astonishing large variety of waves, the ``sounds of space.'' In this talk I will give you a tour of these space sounds, starting with the very early discovery of ``whistlers'' nearly a century ago, and proceeding through my nearly fifty years of research on space plasma waves using spacecraft-borne instrumentation. In addition to being of scientific interest, some of these sounds can even be described as ``musical,'' and have served as the basis for various musical compositions, including a production called ``Sun Rings,'' written by the well-known composer Terry Riley, that has been performed by the Kronos Quartet to audiences all around the world.

  14. Judging sound rotation when listeners and sounds rotate: Sound source localization is a multisystem process.

    PubMed

    Yost, William A; Zhong, Xuan; Najam, Anbar

    2015-11-01

    In four experiments listeners were rotated or were stationary. Sounds came from a stationary loudspeaker or rotated from loudspeaker to loudspeaker around an azimuth array. When either sounds or listeners rotate the auditory cues used for sound source localization change, but in the everyday world listeners perceive sound rotation only when sounds rotate not when listeners rotate. In the everyday world sound source locations are referenced to positions in the environment (a world-centric reference system). The auditory cues for sound source location indicate locations relative to the head (a head-centric reference system), not locations relative to the world. This paper deals with a general hypothesis that the world-centric location of sound sources requires the auditory system to have information about auditory cues used for sound source location and cues about head position. The use of visual and vestibular information in determining rotating head position in sound rotation perception was investigated. The experiments show that sound rotation perception when sources and listeners rotate was based on acoustic, visual, and, perhaps, vestibular information. The findings are consistent with the general hypotheses and suggest that sound source localization is not based just on acoustics. It is a multisystem process.

  15. On the level-dependent penalty for impulse sound.

    PubMed

    Vos, J

    1990-08-01

    At relatively low A-weighted equivalent levels (Leq), road-traffic sounds are rated to be less annoying than impulse sounds. The differences, however, decrease with increasing Leq of the sounds, which indicates that the penalty for impulse sound seems to be level dependent. It was questioned whether the decrease of the penalty with increasing Leq might, at least partly, have been a consequence of the use of the ten-point rating scale. In experiments 1 and 2, the relevance of the level-dependent correction was therefore studied further by using the method of adjustment. The mean results again showed that, at least for gunfire sounds (small arms), the penalty is level dependent. The drawing of firm conclusions, however, was hampered by a relatively large bias in the adjustments. In addition, the overall size of the penalty was lower than obtained in previous rating experiments. The question about the relevance of the level-dependent penalty was reopened in experiment 3 by applying the method of paired comparison. The results confirm the previous findings obtained with the rating experiments: For gunfire sounds at relatively low indoor Leq values, a penalty of about 10 dB is required, and a penalty lower than 5 dB can be applied only in conditions with rather high sound exposure. The results further showed that especially at indoor Leq values higher than about 45 to 50 dB(A), application of a negative penalty may become relevant for specific sounds such as those produced by the 0.50-in. machine gun. Consequently, acoustic measures from which to predict the value of the penalty are highly needed.

  16. A Weighted Harmonic Means Analysis for the Proportional Unbalanced Design.

    ERIC Educational Resources Information Center

    Bonett, Douglas G.

    1982-01-01

    A weighted harmonic means analysis is presented that incorporates all of the available data, preserves the planned proportionality of the design, and avoids the problems associated with the replacement of missing data with sample estimates. (Author/BW)

  17. Could a Weight-Loss Surgery Lead to Alcohol Abuse?

    MedlinePlus

    ... html Could a Weight-Loss Surgery Lead to Alcohol Abuse? Patients who undergo Roux-en-Y gastric ... weight-loss surgery developed a problem such as alcohol abuse or alcoholism, compared with around 11 percent ...

  18. Critical sound propagation in mixtures

    NASA Astrophysics Data System (ADS)

    Folk, R.; Moser, G.

    1998-01-01

    We calculate critical effects in the sound propagation in mixtures near consolute or plait points within a non-asymptotic renormalization group theory and derive general expressions for the frequency-dependent sound velocity and sound attenuation. The critical non-asymptotic time scale in the sound mode in mixtures is set by an effective order parameter Onsager coefficient containing a dynamical parameter related to the enhancement of the thermal conductivity in the mixture, not considered so far. The differences in the critical behavior near the consolute and plait point are due to the different non-asymptotic behavior of the zero-frequency sound velocity. We compare our predictions for the sound velocity and sound absorption near the plait point in 3He-4He mixtures.

  19. A Flexible 360-Degree Thermal Sound Source Based on Laser Induced Graphene

    PubMed Central

    Tao, Lu-Qi; Liu, Ying; Ju, Zhen-Yi; Tian, He; Xie, Qian-Yi; Yang, Yi; Ren, Tian-Ling

    2016-01-01

    A flexible sound source is essential in a whole flexible system. It’s hard to integrate a conventional sound source based on a piezoelectric part into a whole flexible system. Moreover, the sound pressure from the back side of a sound source is usually weaker than that from the front side. With the help of direct laser writing (DLW) technology, the fabrication of a flexible 360-degree thermal sound source becomes possible. A 650-nm low-power laser was used to reduce the graphene oxide (GO). The stripped laser induced graphene thermal sound source was then attached to the surface of a cylindrical bottle so that it could emit sound in a 360-degree direction. The sound pressure level and directivity of the sound source were tested, and the results were in good agreement with the theoretical results. Because of its 360-degree sound field, high flexibility, high efficiency, low cost, and good reliability, the 360-degree thermal acoustic sound source will be widely applied in consumer electronics, multi-media systems, and ultrasonic detection and imaging.

  20. Responses of free-living coastal pelagic fish to impulsive sounds.

    PubMed

    Hawkins, Anthony D; Roberts, Louise; Cheesman, Samuel

    2014-05-01

    The behavior of wild, pelagic fish in response to sound playback was observed with a sonar/echo sounder. Schools of sprat Sprattus sprattus and mackerel Scomber scombrus were examined at a quiet coastal location. The fish were exposed to a short sequence of repeated impulsive sounds, simulating the strikes from a pile driver, at different sound pressure levels. The incidence of behavioral responses increased with increasing sound level. Sprat schools were more likely to disperse and mackerel schools more likely to change depth. The sound pressure levels to which the fish schools responded on 50% of presentations were 163.2 and 163.3 dB re 1 μPa peak-to-peak, and the single strike sound exposure levels were 135.0 and 142.0 dB re 1 μPa(2) s, for sprat and mackerel, respectively, estimated from dose response curves. For sounds leading to mackerel responses, particle velocity levels were also estimated. The method of observation by means of a sonar/echo sounder proved successful in examining the behavior of unrestrained fish exposed to different sound levels. The technique may allow further testing of the relationship between responsiveness, sound level, and sound characteristics for different types of man-made sound, for a variety of fish species under varied conditions.

  1. USAF bioenvironmental noise data handbook. Volume 166: AF/M32T-1 tester, pressurized cabin leakage, aircraft

    NASA Astrophysics Data System (ADS)

    Rau, T. H.

    1982-07-01

    Measured and extrapolated data define the bioacoustic environments produced by a gasoline engine driven cabin leakage tester operating outdoors on a concrete apron at normal rated conditions. Near field data are presented for 37 locations at a wide variety of physical and psychoacoustic measures: overall and band sound pressure levels, C-weighted and A-weighted sound levels, preferred speech interference level, perceived noise level, and limiting times for total daily exposure of personnel with and without standard Air Force ear protectors. Far-field data measured at 36 locations are normalized to standard meteorological conditions and extrapolated from 10 - 1600 meters to derive sets of equal-value contours for these same seven acoustic measures as functions of angle and distance from the source.

  2. Sound from apollo rockets in space.

    PubMed

    Cotten, D; Donn, W L

    1971-02-12

    Low-frequency sound has been recorded on at least two occasions in Bermuda with the passage of Apollo rocket vehicles 188 kilometers aloft. The signals, which are reminiscent of N-waves from sonic booms, are (i) horizontally coherent; (ii) have extremely high (supersonic) trace velocities across the tripartite arrays; (iii) have nearly identical appearance and frequencies; (iv) have essentially identical arrival times after rocket launch; and (v) are the only coherent signals recorded over many hours. These observations seem to establish that the recorded sound comes from the rockets at high elevation. Despite this high elevation, the values of surface pressure appear to be explainable on the basis of a combination of a kinetic theory approach to shock formation in rarefied atmospheres with established gas-dynamics shock theory.

  3. Popcorn: critical temperature, jump and sound.

    PubMed

    Virot, Emmanuel; Ponomarenko, Alexandre

    2015-03-06

    Popcorn bursts open, jumps and emits a 'pop' sound in some hundredths of a second. The physical origin of these three observations remains unclear in the literature. We show that the critical temperature 180°C at which almost all of popcorn pops is consistent with an elementary pressure vessel scenario. We observe that popcorn jumps with a 'leg' of starch which is compressed on the ground. As a result, popcorn is midway between two categories of moving systems: explosive plants using fracture mechanisms and jumping animals using muscles. By synchronizing video recordings with acoustic recordings, we propose that the familiar 'pop' sound of the popcorn is caused by the release of water vapour.

  4. Sound production on a "coaxial saxophone".

    PubMed

    Doc, J-B; Vergez, C; Guillemain, P; Kergomard, J

    2016-11-01

    Sound production on a "coaxial saxophone" is investigated experimentally. The coaxial saxophone is a variant of the cylindrical saxophone made up of two tubes mounted in parallel, which can be seen as a low-frequency analogy of a truncated conical resonator with a mouthpiece. Initially developed for the purposes of theoretical analysis, an experimental verification of the analogy between conical and cylindrical saxophones has never been reported. The present paper explains why the volume of the cylindrical saxophone mouthpiece limits the achievement of a good playability. To limit the mouthpiece volume, a coaxial alignment of pipes is proposed and a prototype of coaxial saxophone is built. An impedance model of coaxial resonator is proposed and validated by comparison with experimental data. Sound production is also studied through experiments with a blowing machine. The playability of the prototype is then assessed and proven for several values of the blowing pressure, of the embouchure parameter, and of the instrument's geometrical parameters.

  5. Method of fan sound mode structure determination

    NASA Technical Reports Server (NTRS)

    Pickett, G. F.; Sofrin, T. G.; Wells, R. W.

    1977-01-01

    A method for the determination of fan sound mode structure in the Inlet of turbofan engines using in-duct acoustic pressure measurements is presented. The method is based on the simultaneous solution of a set of equations whose unknowns are modal amplitude and phase. A computer program for the solution of the equation set was developed. An additional computer program was developed which calculates microphone locations the use of which results in an equation set that does not give rise to numerical instabilities. In addition to the development of a method for determination of coherent modal structure, experimental and analytical approaches are developed for the determination of the amplitude frequency spectrum of randomly generated sound models for use in narrow annulus ducts. Two approaches are defined: one based on the use of cross-spectral techniques and the other based on the use of an array of microphones.

  6. Effort variation regularization in sound field reproduction.

    PubMed

    Stefanakis, Nick; Jacobsen, Finn; Sarris, John

    2010-08-01

    In this paper, active control is used in order to reproduce a given sound field in an extended spatial region. A method is proposed which minimizes the reproduction error at a number of control positions with the reproduction sources holding a certain relation within their complex strengths. Specifically, it is suggested that the phase differential of the source driving signals should be in agreement with the phase differential of the desired sound pressure field. The performance of the suggested method is compared with that of conventional effort regularization, wave field synthesis (WFS), and adaptive wave field synthesis (AWFS), both under free-field conditions and in reverberant rooms. It is shown that effort variation regularization overcomes the problems associated with small spaces and with a low ratio of direct to reverberant energy, improving thus the reproduction accuracy in the listening room.

  7. Popcorn: critical temperature, jump and sound

    PubMed Central

    Virot, Emmanuel; Ponomarenko, Alexandre

    2015-01-01

    Popcorn bursts open, jumps and emits a ‘pop’ sound in some hundredths of a second. The physical origin of these three observations remains unclear in the literature. We show that the critical temperature 180°C at which almost all of popcorn pops is consistent with an elementary pressure vessel scenario. We observe that popcorn jumps with a ‘leg’ of starch which is compressed on the ground. As a result, popcorn is midway between two categories of moving systems: explosive plants using fracture mechanisms and jumping animals using muscles. By synchronizing video recordings with acoustic recordings, we propose that the familiar ‘pop’ sound of the popcorn is caused by the release of water vapour. PMID:25673298

  8. Mathematical models of sound waves in fluids

    NASA Astrophysics Data System (ADS)

    Birkhoff, Garrett

    1987-08-01

    The research discusses mathematical problems of numerical ocean acoustics. These concern the propagation of sound waves in (generally inhomogeneous) elastic fluids, with special reference ot the consistency of the elastic fluid model with ray theory (Fermat-Huygens), in predicting reflection, refraction, and diffraction. The standard modern explanation in terms of relaxation times, although sixty years old, has not yet been substantiated (especially in liquids) by clear answers to many basic questions. These include the following: To what extent is the absorption of sound per wave length, alpha lambda, in air, CO2, and other dilute gases determined by the absolute temperature, T, and the ratio f/p of the frequency to the pressure. To what extent are contributions to alpha from different causes demonstrably additive, in gases and in liquids.

  9. Sound naming in neurodegenerative disease.

    PubMed

    Chow, Maggie L; Brambati, Simona M; Gorno-Tempini, Maria Luisa; Miller, Bruce L; Johnson, Julene K

    2010-04-01

    Modern cognitive neuroscientific theories and empirical evidence suggest that brain structures involved in movement may be related to action-related semantic knowledge. To test this hypothesis, we examined the naming of environmental sounds in patients with corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP), two neurodegenerative diseases associated with cognitive and motor deficits. Subjects were presented with 56 environmental sounds: 28 sounds were of objects that required manipulation when producing the sound, and 28 sounds were of objects that required no manipulation. Subjects were asked to provide the name of the object that produced the sound and also complete a sound-picture matching condition. Subjects included 33 individuals from four groups: CBD/PSP, Alzheimer disease, frontotemporal dementia, and normal controls. We hypothesized that CBD/PSP patients would exhibit impaired naming performance compared with controls, but the impairment would be most apparent when naming sounds associated with actions. We also explored neural correlates of naming environmental sounds using voxel-based morphometry (VBM) of brain MRI. As expected, CBD/PSP patients scored lower on environmental sounds naming (p<0.007) compared with the controls. In particular, the CBD/PSP patients scored the lowest when naming sounds of manipulable objects (p<0.05), but did not show deficits in naming sounds of non-manipulable objects. VBM analysis across all groups showed that performance in naming sounds of manipulable objects correlated with atrophy in the left pre-motor region, extending from area six to the middle and superior frontal gyrus. These results indicate an association between impairment in the retrieval of action-related names and the motor system, and suggest that difficulty in naming manipulable sounds may be related to atrophy in the pre-motor cortex. Our results support the hypothesis that retrieval of action-related semantic knowledge involves motor

  10. Automated Blood Pressure Measurement

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The Vital-2 unit pictured is a semi-automatic device that permits highly accurate blood pressure measurement, even by untrained personnel. Developed by Meditron Instrument Corporation, Milford, New Hampshire, it is based in part on NASA technology found in a similar system designed for automatic monitoring of astronauts' blood pressure. Vital-2 is an advancement over the familiar arm cuff, dial and bulb apparatus customarily used for blood pressure checks. In that method, the physician squeezes the bulb to inflate the arm cuff, which restricts the flow of blood through the arteries. As he eases the pressure on the arm, he listens, through a stethoscope, to the sounds of resumed blood flow as the arteries expand and contract. Taking dial readings related to sound changes, he gets the systolic (contracting) and diastolic (expanding) blood pressure measurements. The accuracy of the method depends on the physician's skill in interpreting the sounds. Hospitals sometimes employ a more accurate procedure, but it is "invasive," involving insertion of a catheter in the artery.

  11. Evaluation of smartphone sound measurement applicationsa)

    PubMed Central

    Shaw, Peter B.

    2015-01-01

    This study reports on the accuracy of smartphone sound measurement applications (apps) and whether they can be appropriately employed for occupational noise measurements. A representative sample of smartphones and tablets on various platforms were acquired, more than 130 iOS apps were evaluated but only 10 apps met our selection criteria. Only 4 out of 62 Android apps were tested. The results showed two apps with mean differences of 0.07 dB (unweighted) and −0.52 dB (A-weighted) from the reference values. Two other apps had mean differences within ± 2 dB. The study suggests that certain apps may be appropriate for use in occupational noise measurements. PMID:25236152

  12. Sound Levels and Risk Perceptions of Music Students During Classes.

    PubMed

    Rodrigues, Matilde A; Amorim, Marta; Silva, Manuela V; Neves, Paula; Sousa, Aida; Inácio, Octávio

    2015-01-01

    It is well recognized that professional musicians are at risk of hearing damage due to the exposure to high sound pressure levels during music playing. However, it is important to recognize that the musicians' exposure may start early in the course of their training as students in the classroom and at home. Studies regarding sound exposure of music students and their hearing disorders are scarce and do not take into account important influencing variables. Therefore, this study aimed to describe sound level exposures of music students at different music styles, classes, and according to the instrument played. Further, this investigation attempted to analyze the perceptions of students in relation to exposure to loud music and consequent health risks, as well as to characterize preventive behaviors. The results showed that music students are exposed to high sound levels in the course of their academic activity. This exposure is potentiated by practice outside the school and other external activities. Differences were found between music style, instruments, and classes. Tinnitus, hyperacusis, diplacusis, and sound distortion were reported by the students. However, students were not entirely aware of the health risks related to exposure to high sound pressure levels. These findings reflect the importance of starting intervention in relation to noise risk reduction at an early stage, when musicians are commencing their activity as students.

  13. Speed of Sound and Ultrasound Absorption in Ionic Liquids.

    PubMed

    Dzida, Marzena; Zorębski, Edward; Zorębski, Michał; Żarska, Monika; Geppert-Rybczyńska, Monika; Chorążewski, Mirosław; Jacquemin, Johan; Cibulka, Ivan

    2017-03-08

    A complete review of the literature data on the speed of sound and ultrasound absorption in pure ionic liquids (ILs) is presented. Apart of the analysis of data published to date, the significance of the speed of sound in ILs is regarded. An analysis of experimental methods described in the literature to determine the speed of sound in ILs as a function of temperature and pressure is reported, and the relevance of ultrasound absorption in acoustic investigations is discussed. Careful attention was paid to highlight possible artifacts, and side phenomena related to the absorption and relaxation present in such measurements. Then, an overview of existing data is depicted to describe the temperature and pressure dependences on the speed of sound in ILs, as well as the impact of impurities in ILs on this property. A relation between ions structure and speeds of sound is presented by highlighting existing correlation and evaluative methods described in the literature. Importantly, a critical analysis of speeds of sound in ILs vs those in classical molecular solvents is presented to compare these two classes of compounds. The last part presents the importance of acoustic investigations for chemical engineering design and possible industrial applications of ILs.

  14. Sound fields in generally shaped curved ear canals.

    PubMed

    Hudde, H; Schmidt, S

    2009-05-01

    The sound field in the external ear can be subdivided into a distinctly three-dimensional part in front of pinna and concha, a fairly regular part in the core region of ear canals, and a less regular part in the drum coupling region near the tympanic membrane. The different parts of the sound field and their interaction have been studied using finite elements. A "pinna box" enclosing the pinna provides both a realistic coupling of the external space to the ear canal and the generation of sound. The sound field in the core region turns out to be not that regular as mostly assumed: near pressure minima and maxima "one-sided" isosurfaces (surfaces of equal pressure magnitude) occur, which are inconsistent with the notion of a middle axis, in principle. Nevertheless such isosurfaces can be seen as part of a "fundamental sound field," which is governed by the principle of minimum energy. Actually, the sound transformation through narrow ducts is little affected by one-sided isosurfaces in between. As expected, the beginning of the core region depends on frequency. If the full audio range up to 20 kHz is to be covered, a location in the first bend of the ear canal is found.

  15. Comprehensive measures of sound exposures in cinemas using smart phones.

    PubMed

    Huth, Markus E; Popelka, Gerald R; Blevins, Nikolas H

    2014-01-01

    Sensorineural hearing loss from sound overexposure has a considerable prevalence. Identification of sound hazards is crucial, as prevention, due to a lack of definitive therapies, is the sole alternative to hearing aids. One subjectively loud, yet little studied, potential sound hazard is movie theaters. This study uses smart phones to evaluate their applicability as a widely available, validated sound pressure level (SPL) meter. Therefore, this study measures sound levels in movie theaters to determine whether sound levels exceed safe occupational noise exposure limits and whether sound levels in movie theaters differ as a function of movie, movie theater, presentation time, and seat location within the theater. Six smart phones with an SPL meter software application were calibrated with a precision SPL meter and validated as an SPL meter. Additionally, three different smart phone generations were measured in comparison to an integrating SPL meter. Two different movies, an action movie and a children's movie, were measured six times each in 10 different venues (n = 117). To maximize representativeness, movies were selected focusing on large release productions with probable high attendance. Movie theaters were selected in the San Francisco, CA, area based on whether they screened both chosen movies and to represent the largest variety of theater proprietors. Measurements were analyzed in regard to differences between theaters, location within the theater, movie, as well as presentation time and day as indirect indicator of film attendance. The smart phone measurements demonstrated high accuracy and reliability. Overall, sound levels in movie theaters do not exceed safe exposure limits by occupational standards. Sound levels vary significantly across theaters and demonstrated statistically significant higher sound levels and exposures in the action movie compared to the children's movie. Sound levels decrease with distance from the screen. However, no influence on

  16. [Analysing noise levels in dental environment. Air turbine sound response to various physical factors].

    PubMed

    Oka, S

    1989-10-01

    Dental Air Turbine sound depends on the mechanical performance such as rotation and it is impossible to neglect connections of the sound with fluid mechanics and acoustics. Turbine sound must be considered from the standpoint of the sound pressure level and frequency component. In this study, the sound samples was measured and analysed in octave band spectrum. Turbine sound has three resonance bands of the frequency with the range from 0 to 1,600 Hz and the resonance band increased as air pressure increased. The frequency of the second resonance band decreased as the cutting load and cutting point diameter increased. Damping of the second resonance band frequency shifted downward by polishing point.

  17. A Numerical Experiment on the Role of Surface Shear Stress in the Generation of Sound

    NASA Technical Reports Server (NTRS)

    Shariff, Karim; Wang, Meng; Merriam, Marshal (Technical Monitor)

    1996-01-01

    The sound generated due to a localized flow over an infinite flat surface is considered. It is known that the unsteady surface pressure, while appearing in a formal solution to the Lighthill equation, does not constitute a source of sound but rather represents the effect of image quadrupoles. The question of whether a similar surface shear stress term constitutes a true source of dipole sound is less settled. Some have boldly assumed it is a true source while others have argued that, like the surface pressure, it depends on the sound field (via an acoustic boundary layer) and is therefore not a true source. A numerical experiment based on the viscous, compressible Navier-Stokes equations was undertaken to investigate the issue. A small region of a wall was oscillated tangentially. The directly computed sound field was found to to agree with an acoustic analogy based calculation which regards the surface shear as an acoustically compact dipole source of sound.

  18. Interpolated Sounding and Gridded Sounding Value-Added Products

    SciTech Connect

    M. P. Jensen; Toto, T.

    2016-03-01

    Standard Atmospheric Radiation Measurement (ARM) Climate Research Facility sounding files provide atmospheric state data in one dimension of increasing time and height per sonde launch. Many applications require a quick estimate of the atmospheric state at higher time resolution. The INTERPOLATEDSONDE (i.e., Interpolated Sounding) Value-Added Product (VAP) transforms sounding data into continuous daily files on a fixed time-height grid, at 1-minute time resolution, on 332 levels, from the surface up to a limit of approximately 40 km. The grid extends that high so the full height of soundings can be captured; however, most soundings terminate at an altitude between 25 and 30 km, above which no data is provided. Between soundings, the VAP linearly interpolates atmospheric state variables in time for each height level. In addition, INTERPOLATEDSONDE provides relative humidity scaled to microwave radiometer (MWR) observations.

  19. Characteristics of the audio sound generated by ultrasound imaging systems.

    PubMed

    Fatemi, Mostafa; Alizad, Azra; Greenleaf, James F

    2005-03-01

    Medical ultrasound scanners use high-energy pulses to probe the human body. The radiation force resulting from the impact of such pulses on an object can vibrate the object, producing a localized high-intensity sound in the audible range. Here, a theoretical model for the audio sound generated by ultrasound scanners is presented. This model describes the temporal and spectral characteristics of the sound. It has been shown that the sound has rich frequency components at the pulse repetition frequency and its harmonics. Experiments have been conducted in a water tank to measure the sound generated by a clinical ultrasound scanner in various operational modes. Results are in general agreement with the theory. It is shown that a typical ultrasound scanner with a typical spatial-peak pulse-average intensity value at 2 MHz may generate a localized sound-pressure level close to 100 dB relative to 20 microPa in the audible (< 20 kHz) range under laboratory conditions. These findings suggest that fetuses may become exposed to a high-intensity audio sound during maternal ultrasound examinations. Therefore, contrary to common beliefs, ultrasound may not be considered a passive tool in fetal imaging.

  20. Characteristics of the audio sound generated by ultrasound imaging systems

    NASA Astrophysics Data System (ADS)

    Fatemi, Mostafa; Alizad, Azra; Greenleaf, James F.

    2005-03-01

    Medical ultrasound scanners use high-energy pulses to probe the human body. The radiation force resulting from the impact of such pulses on an object can vibrate the object, producing a localized high-intensity sound in the audible range. Here, a theoretical model for the audio sound generated by ultrasound scanners is presented. This model describes the temporal and spectral characteristics of the sound. It has been shown that the sound has rich frequency components at the pulse repetition frequency and its harmonics. Experiments have been conducted in a water tank to measure the sound generated by a clinical ultrasound scanner in various operational modes. Results are in general agreement with the theory. It is shown that a typical ultrasound scanner with a typical spatial-peak pulse-average intensity value at 2 MHz may generate a localized sound-pressure level close to 100 dB relative to 20 μPa in the audible (<20 kHz) range under laboratory conditions. These findings suggest that fetuses may become exposed to a high-intensity audio sound during maternal ultrasound examinations. Therefore, contrary to common beliefs, ultrasound may not be considered a passive tool in fetal imaging..

  1. Design and implementation of an underwater sound recording device

    SciTech Connect

    Martinez, Jayson J.; Myers, Joshua R.; Carlson, Thomas J.; Deng, Zhiqun; Rohrer, John S.; Caviggia, Kurt A.

    2011-09-19

    The purpose of this study was to design and build two versions of an underwater sound recording device. The device designed is referred to as the Underwater Sound Recorder (USR), which can be connected to one or two hydrophones or other underwater sound sensors. The URS contains a 26 dB preamplifier and a user selectable gain that permits additional amplification of input to the system from 26 dB to 46 dB. Signals within the frequency range up to 15 kHz may be recorded using the USR. Examples of USR applications are monitoring underwater processes that have the potential to create large pressure waves that could potentially harm fish or other aquatic life, such as underwater explosions or pile driving. Additional applications are recording sound generated by vessels or the vocalizations of some marine mammals, such as the calls from many species of whales.

  2. Accessory pathway for sound transfer in a neotropical frog.

    PubMed Central

    Narins, P M; Ehret, G; Tautz, J

    1988-01-01

    A portion of the lateral body wall overlying the lung cavity of the arboreal frog, Eleutherodactylus coqui, vibrates in response to free-field sound. Peak displacement amplitude of the body wall in response to a natural call note presented at 73 decibels sound pressure level is 1.70 X 10(-9) m, roughly 8 decibels less than that of the ipsilateral eardrum, as measured by laser Doppler vibrometry. We show that the vibration magnitude varies predictably across the body profile and is posture and frequency dependent. Two routes to the inner ear are described for sounds impinging on the body wall; either of these accessory pathways could modify direct input from the peripheral auditory system and enhance sound localization in these small vertebrates. PMID:3422747

  3. Reliability of sound attenuation in Florida scrub habitat and behavioral implications

    NASA Astrophysics Data System (ADS)

    Nelson, Brian S.

    2003-05-01

    Attenuation over distance in natural habitat is often difficult to predict when measured without respect to sound frequency. The physical-acoustic structure of Florida scrub habitat is described and both attenuation and reliability of attenuation are measured as a function of sound frequency, over several distances, speaker elevations, and microphone elevations. The spatial context of sound propagation in Florida scrub habitat is discussed and a model designed to describe contributions to overall attenuation from individual factors is presented. Sound frequencies below ~3.5 kHz attenuate more reliably than higher sound frequencies, suggesting that animals should pay greatest attention to relatively low sound frequencies when they assess attenuation or estimate sound-pressure level.

  4. Common Sole Larvae Survive High Levels of Pile-Driving Sound in Controlled Exposure Experiments

    PubMed Central

    Bolle, Loes J.; de Jong, Christ A. F.; Bierman, Stijn M.; van Beek, Pieter J. G.; van Keeken, Olvin A.; Wessels, Peter W.; van Damme, Cindy J. G.; Winter, Hendrik V.; de Haan, Dick; Dekeling, René P. A.

    2012-01-01

    In view of the rapid extension of offshore wind farms, there is an urgent need to improve our knowledge on possible adverse effects of underwater sound generated by pile-driving. Mortality and injuries have been observed in fish exposed to loud impulse sounds, but knowledge on the sound levels at which (sub-)lethal effects occur is limited for juvenile and adult fish, and virtually non-existent for fish eggs and larvae. A device was developed in which fish larvae can be exposed to underwater sound. It consists of a rigid-walled cylindrical chamber driven by an electro-dynamical sound projector. Samples of up to 100 larvae can be exposed simultaneously to a homogeneously distributed sound pressure and particle velocity field. Recorded pile-driving sounds could be reproduced accurately in the frequency range between 50 and 1000 Hz, at zero to peak pressure levels up to 210 dB re 1µPa2 (zero to peak pressures up to 32 kPa) and single pulse sound exposure levels up to 186 dB re 1µPa2s. The device was used to examine lethal effects of sound exposure in common sole (Solea solea) larvae. Different developmental stages were exposed to various levels and durations of pile-driving sound. The highest cumulative sound exposure level applied was 206 dB re 1µPa2s, which corresponds to 100 strikes at a distance of 100 m from a typical North Sea pile-driving site. The results showed no statistically significant differences in mortality between exposure and control groups at sound exposure levels which were well above the US interim criteria for non-auditory tissue damage in fish. Although our findings cannot be extrapolated to fish larvae in general, as interspecific differences in vulnerability to sound exposure may occur, they do indicate that previous assumptions and criteria may need to be revised. PMID:22431996

  5. Discovery of Sound in the Sea (DOSITS) Website Development

    DTIC Science & Technology

    2013-03-04

    life affect ocean sound levels? • Science of Sound > Sounds in the Sea > How will ocean acidification affect ocean sound levels? • Science of Sound...Science of Sound > Sounds in the Sea > How does shipping affect ocean sound levels? • Science of Sound > Sounds in the Sea > How does marine

  6. Variations of NICU sound by location and time of day.

    PubMed

    Matook, Sherry A; Sullivan, Mary C; Salisbury, Amy; Miller, Robin J; Lester, Barry M

    The primary aim of this study was to identify time periods of sound levels >45 decibels (dB) in a large Level III NICU. The second aim was to determine whether there were differences in decibel levels across the five bays of the NICU, the four quadrants within each bay, and two 12-hour shifts. A repeated measures design was used. Bay, quadrant, and shift were randomly selected for sampling. Staff and visitors were blinded to the location of the sound meter, which was placed in one of five identical wooden boxes and was preset to record for 12 hours. Sound levels were recorded every 60 seconds over 40 12-hour periods, 20 during the day shift and 20 during the night shift. Total hours measured were 480. Data were collected every other day during a three-month period. Covariates of staffing, infant census, infant acuity, and medical equipment were collected. The main outcome variable was sound levels in decibels, with units of measurement of energy equivalent sound level (Leq), peak instantaneous sound pressure level, and maximum sound pressure level during each interval for a total of 480 hours. All sound levels were >45 dB, with average readings ranging from 49.5 to 89.5 dB. The middle bay had the highest levels, with an Leq of 85.74 dB. Quadrants at the back of a bay were louder than quadrants at the front of a bay. The day shift had higher decibel levels than the night shift. Covariates did not differ across bays or shifts.

  7. Sounds in the Sea

    NASA Astrophysics Data System (ADS)

    Medwin, Herman

    2005-07-01

    Underwater acousticians and acoustical oceanographers use sound as the premier tool to determine the detailed characteristics of physical and biological bodies and processes at sea. Sounds in the Sea is a comprehensive and accessible textbook on ocean acoustics and acoustical oceanography. Chapters 1 9 provide the basic tools of ocean acoustics. The following fifteen chapters are written by many of the world's most successful ocean researchers. These chapters describe modern developments, and are divided into four sections: Studies of the Near Surface Ocean; Bioacoustical Studies; Studies of Ocean Dynamics; Studies of the Ocean Bottom. This is an invaluable textbook for any course in ocean acoustics for the physical and biological ocean sciences, and engineering. It will also serve as a reference for researchers and professionals in ocean acoustics, and an excellent introduction to the topic for scientists from related fields. Will become THE advanced but accessible textbook on all aspects of ocean acoustics for students in oceanography, engineering, and physics, and will also serve as a reference for researchers and professionals Contains fifteen chapters by many of the world's most successful ocean researchers, describing modern research developments Main author Medwin is world-renowned in ocean acoustics

  8. Respiratory sounds compression.

    PubMed

    Yadollahi, Azadeh; Moussavi, Zahra

    2008-04-01

    Recently, with the advances in digital signal processing, compression of biomedical signals has received great attention for telemedicine applications. In this paper, an adaptive transform coding-based method for compression of respiratory and swallowing sounds is proposed. Using special characteristics of respiratory sounds, the recorded signals are divided into stationary and nonstationary portions, and two different bit allocation methods (BAMs) are designed for each portion. The method was applied to the data of 12 subjects and its performance in terms of overall signal-to-noise ratio (SNR) values was calculated at different bit rates. The performance of different quantizers was also considered and the sensitivity of the quantizers to initial conditions has been alleviated. In addition, the fuzzy clustering method was examined for classifying the signal into different numbers of clusters and investigating the performance of the adaptive BAM with increasing the number of classes. Furthermore, the effects of assigning different numbers of bits for encoding stationary and nonstationary portions of the signal were studied. The adaptive BAM with variable number of bits was found to improve the SNR values of the fixed BAM by 5 dB. Last, the possibility of removing the training part for finding the parameters of adaptive BAMs for each individual was investigated. The results indicate that it is possible to use a predefined set of BAMs for all subjects and remove the training part completely. Moreover, the method is fast enough to be implemented for real-time application.

  9. Puget Sound telecommuting demonstration

    SciTech Connect

    Quaid, M.; Heifetz, L.; Farley, M.; Christensen, D.; Ulberg, C.; Gordon, A.; Spain, D.; Whitaker, B.

    1992-04-01

    This report discusses the Puget Sound Telecommuting demonstration project. This is a part-time work and transportation alternative that substitutes the normal work commute with the choice of working at home or at an office close to home. According to Link Resources, a research and consulting firm located in New York, there were 4.6 million part-time home telecommuters in the United States in 1991. This figure, which included only company employees who work at home during normal business hours, is up from 3.4 million in 1990, an increase of 35 percent in one year. Part-time telecommuters average 2.5 days per week at home. (There are also about 876,000 full-time telecommuters in the US.) The study done by Link Resources estimates that 4.5 percent of the civilian work force age 18 or older is telecommuting. The Washington State Energy Office (WSEO) began exploring telecommuting as an alternate route to work for Washington, first through The Governor`s Conference on Telecommuting in June 1989. The conference raised corporate and government awareness of telecommuting, and set the stage for further investigation. In 1990, WSEO launched the Puget Sound Telecommuting Demonstration to explore the environmental, organizational, and personal sides of telecommuting. This report presents the interim research results.

  10. Puget Sound telecommuting demonstration

    SciTech Connect

    Quaid, M.; Heifetz, L.; Farley, M.; Christensen, D. ); Ulberg, C.; Gordon, A.; Spain, D.; Whitaker, B. )

    1992-04-01

    This report discusses the Puget Sound Telecommuting demonstration project. This is a part-time work and transportation alternative that substitutes the normal work commute with the choice of working at home or at an office close to home. According to Link Resources, a research and consulting firm located in New York, there were 4.6 million part-time home telecommuters in the United States in 1991. This figure, which included only company employees who work at home during normal business hours, is up from 3.4 million in 1990, an increase of 35 percent in one year. Part-time telecommuters average 2.5 days per week at home. (There are also about 876,000 full-time telecommuters in the US.) The study done by Link Resources estimates that 4.5 percent of the civilian work force age 18 or older is telecommuting. The Washington State Energy Office (WSEO) began exploring telecommuting as an alternate route to work for Washington, first through The Governor's Conference on Telecommuting in June 1989. The conference raised corporate and government awareness of telecommuting, and set the stage for further investigation. In 1990, WSEO launched the Puget Sound Telecommuting Demonstration to explore the environmental, organizational, and personal sides of telecommuting. This report presents the interim research results.

  11. Sound Localization in Multisource Environments

    DTIC Science & Technology

    2009-03-01

    D. (1997). Factors affecting the relative salience of sound localization cues. In Gilkey, R. and Anderson, T., editors, Binaural and Spatial Hearing...AFRL-RH-WP-TR-2009-0032 Sound Localization in Multisource Environments Nandini Iyer Douglas S. Brungart Brian D. Simpson Warfighter...From - To) October 2004 – September 2008 4. TITLE AND SUBTITLE Sound Localization in Multisource Environments 5a. CONTRACT NUMBER In-House 5b

  12. Analysis of environmental sounds

    NASA Astrophysics Data System (ADS)

    Lee, Keansub

    Environmental sound archives - casual recordings of people's daily life - are easily collected by MPS players or camcorders with low cost and high reliability, and shared in the web-sites. There are two kinds of user generated recordings we would like to be able to handle in this thesis: Continuous long-duration personal audio and Soundtracks of short consumer video clips. These environmental recordings contain a lot of useful information (semantic concepts) related with activity, location, occasion and content. As a consequence, the environment archives present many new opportunities for the automatic extraction of information that can be used in intelligent browsing systems. This thesis proposes systems for detecting these interesting concepts on a collection of these real-world recordings. The first system is to segment and label personal audio archives - continuous recordings of an individual's everyday experiences - into 'episodes' (relatively consistent acoustic situations lasting a few minutes or more) using the Bayesian Information Criterion and spectral clustering. The second system is for identifying regions of speech or music in the kinds of energetic and highly-variable noise present in this real-world sound. Motivated by psychoacoustic evidence that pitch is crucial in the perception and organization of sound, we develop a noise-robust pitch detection algorithm to locate speech or music-like regions. To avoid false alarms resulting from background noise with strong periodic components (such as air-conditioning), a new scheme is added in order to suppress these noises in the domain of autocorrelogram. In addition, the third system is to automatically detect a large set of interesting semantic concepts; which we chose for being both informative and useful to users, as well as being technically feasible. These 25 concepts are associated with people's activities, locations, occasions, objects, scenes and sounds, and are based on a large collection of

  13. Sounds like Team Spirit

    NASA Technical Reports Server (NTRS)

    Hoffman, Edward

    2002-01-01

    I recently accompanied my son Dan to one of his guitar lessons. As I sat in a separate room, I focused on the music he was playing and the beautiful, robust sound that comes from a well-played guitar. Later that night, I woke up around 3 am. I tend to have my best thoughts at this hour. The trouble is I usually roll over and fall back asleep. This time I was still awake an hour later, so I got up and jotted some notes down in my study. I was thinking about the pure, honest sound of a well-played instrument. From there my mind wandered into the realm of high-performance teams and successful projects. (I know this sounds weird, but this is the sort of thing I think about at 3 am. Maybe you have your own weird thoughts around that time.) Consider a team in relation to music. It seems to me that a crack team can achieve a beautiful, perfect unity in the same way that a band of brilliant musicians can when they're in harmony with one another. With more than a little satisfaction I have to admit, I started to think about the great work performed for you by the Knowledge Sharing team, including this magazine you are reading. Over the past two years I personally have received some of my greatest pleasures as the APPL Director from the Knowledge Sharing activities - the Masters Forums, NASA Center visits, ASK Magazine. The Knowledge Sharing team expresses such passion for their work, just like great musicians convey their passion in the music they play. In the case of Knowledge Sharing, there are many factors that have made this so enjoyable (and hopefully worthwhile for NASA). Three ingredients come to mind -- ingredients that have produced a signature sound. First, through the crazy, passionate playing of Alex Laufer, Michelle Collins, Denise Lee, and Todd Post, I always know that something startling and original is going to come out of their activities. This team has consistently done things that are unique and innovative. For me, best of all is that they are always

  14. Sound waves in multifractional liquids with bubbles

    NASA Astrophysics Data System (ADS)

    Gubaidullin, D. A.; Gafiyatov, R. N.

    2017-01-01

    The propagation of sound waves in multifractional mixtures of liquid with vapor–gas and gas bubbles of different sizes and different compositions with phase transitions is studied. The dispersed phase consists of N+M fractions having various gases in bubbles and different in the bubbles radii. Phase transitions accounted for N fractions. The total bubble volume concentration is small (less than 1%). The dispersion relation is derived and dispersion curves is built. The evolution of the weak pulsed perturbations of the pressure in this mixture was calculated numerically.

  15. Diffraction of sound by nearly rigid barriers

    NASA Technical Reports Server (NTRS)

    Hadden, W. J., Jr.; Pierce, A. D.

    1976-01-01

    The diffraction of sound by barriers with surfaces of large, but finite, acoustic impedance was analyzed. Idealized source-barrier-receiver configurations in which the barriers may be considered as semi-infinite wedges are discussed. Particular attention is given to situations in which the source and receiver are at large distances from the tip of the wedge. The expression for the acoustic pressure in this limiting case is compared with the results of Pierce's analysis of diffraction by a rigid wedge. An expression for the insertion loss of a finite impedance barrier is compared with insertion loss formulas which are used extensively in selecting or designing barriers for noise control.

  16. Sound generation by a stenosis in a pipe

    NASA Technical Reports Server (NTRS)

    Hardin, J. C.; Pope, D. S.

    1990-01-01

    This paper presents a computational aeroacoustics study of sound generated by low Mach number flow through a closure (stenosis) in a circular pipe. The time-dependent incompressible flowfield in the pipe is first computed utilizing a vorticity/stream function formulation. The known velocity field is then utilized to determine the incompressible fluctuating pressure in the pipe. This hydrodynamic pressure field is then utilized to compute a hydrodynamic density perturbation to the constant incompressible density through the equation of state. Knowledge of this complete hydrodynamic field is then employed as the source of the resulting sound radiation. This tripartite technique allows separation of the compressible fluctuations from the purely hydrodynamic fluctuations. Results of the analysis are compared with experimental measurements of sound radiated by such a flow.

  17. Source and listener directivity for interactive wave-based sound propagation.

    PubMed

    Mehra, Ravish; Antani, Lakulish; Kim, Sujeong; Manocha, Dinesh

    2014-04-01

    We present an approach to model dynamic, data-driven source and listener directivity for interactive wave-based sound propagation in virtual environments and computer games. Our directional source representation is expressed as a linear combination of elementary spherical harmonic (SH) sources. In the preprocessing stage, we precompute and encode the propagated sound fields due to each SH source. At runtime, we perform the SH decomposition of the varying source directivity interactively and compute the total sound field at the listener position as a weighted sum of precomputed SH sound fields. We propose a novel plane-wave decomposition approach based on higher-order derivatives of the sound field that enables dynamic HRTF-based listener directivity at runtime. We provide a generic framework to incorporate our source and listener directivity in any offline or online frequency-domain wave-based sound propagation algorithm. We have integrated our sound propagation system in Valve's Source game engine and use it to demonstrate realistic acoustic effects such as sound amplification, diffraction low-passing, scattering, localization, externalization, and spatial sound, generated by wave-based propagation of directional sources and listener in complex scenarios. We also present results from our preliminary user study.

  18. Bilateral sound propagation characteristics in electronic TMJ sound recording.

    PubMed

    Yang, K P; Koh, K H; Williams, W J; Widmalm, S E; Djurdjanovic, D

    1999-01-01

    Temporomandibular Joint (TMJ) sounds, clicking and crepitation, are important signs of possible TM disorder or dysfunction (TMD). The sound are usually recorded and observed by stethoscope auscultation or palpation. Sound from one TMJ may propagate through head tissues and be recorded on the contra lateral side misleading the examiner to classify both joints as non-silent. Errors in localization of sound source may lead to an erroneous diagnosis. Widmalm et al. (1997) suggested a mathematical model for estimation of the sound propagation characteristics through the head tissues. A modified model applying the auto-spectral density and cross-spectral density of the signal was used to estimate the bilateral sound propagation characteristics of temporomandibular joint sounds from two subjects. The result indicates that the head tissues act as a bandpass filter causing strong attenuation in some frequency areas with little attenuation in others. The phase response of the transfer function provides a good mean to estimate the latency in time between sounds.

  19. Interpolated Sounding and Gridded Sounding Value-Added Products

    SciTech Connect

    Toto, T.; Jensen, M.

    2016-03-01

    Standard Atmospheric Radiation Measurement (ARM) Climate Research Facility sounding files provide atmospheric state data in one dimension of increasing time and height per sonde launch. Many applications require a quick estimate of the atmospheric state at higher time resolution. The INTERPOLATEDSONDE (i.e., Interpolated Sounding) Value-Added Product (VAP) transforms sounding data into continuous daily files on a fixed time-height grid, at 1-minute time resolution, on 332 levels, from the surface up to a limit of approximately 40 km. The grid extends that high so the full height of soundings can be captured; however, most soundings terminate at an altitude between 25 and 30 km, above which no data is provided. Between soundings, the VAP linearly interpolates atmospheric state variables in time for each height level. In addition, INTERPOLATEDSONDE provides relative humidity scaled to microwave radiometer (MWR) observations.The INTERPOLATEDSONDE VAP, a continuous time-height grid of relative humidity-corrected sounding data, is intended to provide input to higher-order products, such as the Merged Soundings (MERGESONDE; Troyan 2012) VAP, which extends INTERPOLATEDSONDE by incorporating model data. The INTERPOLATEDSONDE VAP also is used to correct gaseous attenuation of radar reflectivity in products such as the KAZRCOR VAP.

  20. Nonlinear behavior of the tarka flute's distinctive sounds

    NASA Astrophysics Data System (ADS)

    Gérard, Arnaud; Yapu-Quispe, Luis; Sakuma, Sachiko; Ghezzi, Flavio; Ramírez-Ávila, Gonzalo Marcelo

    2016-09-01

    The Andean tarka flute generates multiphonic sounds. Using spectral techniques, we verify two distinctive musical behaviors and the nonlinear nature of the tarka. Through nonlinear time series analysis, we determine chaotic and hyperchaotic behavior. Experimentally, we observe that by increasing the blow pressure on different fingerings, peculiar changes from linear to nonlinear patterns are produced, leading ultimately to quenching.