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Sample records for intracochlear sound pressure

  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. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. [Comparison of differental intracochlear pressures between round window stimulation and ear canal stimulation].

    PubMed

    Wang, Xuelin

    2012-12-01

    Stimulation of the round window (RW) for coupling an implantable hearing system to the cochlea has gained increasing clinical importance. To compare the vibration transfer to the cochlear fluids and partition in response to normal acoustic stimulation and to mechanical stimulation of the RW, we carried out an acoustic-structure coupled finite element analysis using a recently developed finite element (FE) model in our laboratory, which consisted of external ear canal, middle ear and cochlea. Intracochlear pressures were derived during normal forward sound stimulation as well as reverse RW stimulation. A model was utilized to calculate the force required of an actuator at the RW to produce a differential intracochlear pressure that is equivalent to a stimulus produced in normal ear by a given external ear-canal pressure. The current results provided further information to support the optimization of the actuators and adapt existing prostheses for RW stimulation in order to insure sufficient acoustic output.

  8. Postinsertional Cable Movements of Cochlear Implant Electrodes and Their Effects on Intracochlear Pressure

    PubMed Central

    Karimi, D.; Luger, J.; Ernst, A.

    2016-01-01

    Introduction. To achieve a functional atraumatic cochlear implantation, intracochlear pressure changes during the procedure should be minimized. Postinsertional cable movements are assumed to induce intracochlear pressure changes. The aim of this study was to observe intracochlear pressure changes due to postinsertional cable movements. Materials and Methods. Intracochlear pressure changes were recorded in a cochlear model with a micro-pressure sensor positioned in the apical region of the cochlea model to follow the maximum amplitude and pressure gain velocity in intracochlear pressure. A temporal bone mastoid cavity was attached to the model to simulate cable positioning. The compared conditions were (1) touching the unsealed electrode, (2) touching the sealed electrode, (3) cable storage with an unfixed cable, and (4) cable storage with a fixed cable. Results. We found statistically significant differences in the occurrence of maximum amplitude and pressure gain velocity in intracochlear pressure changes under the compared conditions. Comparing the cable storage conditions, a cable fixed mode offers significantly lower maximum pressure amplitude and pressure gain velocity than the nonfixed mode. Conclusion. Postinsertional cable movement led to a significant pressure transfer into the cochlea. Before positioning the electrode cable in the mastoid cavity, fixation of the cable is recommended. PMID:27900329

  9. Postinsertional Cable Movements of Cochlear Implant Electrodes and Their Effects on Intracochlear Pressure.

    PubMed

    Todt, I; Karimi, D; Luger, J; Ernst, A; Mittmann, P

    2016-01-01

    Introduction. To achieve a functional atraumatic cochlear implantation, intracochlear pressure changes during the procedure should be minimized. Postinsertional cable movements are assumed to induce intracochlear pressure changes. The aim of this study was to observe intracochlear pressure changes due to postinsertional cable movements. Materials and Methods. Intracochlear pressure changes were recorded in a cochlear model with a micro-pressure sensor positioned in the apical region of the cochlea model to follow the maximum amplitude and pressure gain velocity in intracochlear pressure. A temporal bone mastoid cavity was attached to the model to simulate cable positioning. The compared conditions were (1) touching the unsealed electrode, (2) touching the sealed electrode, (3) cable storage with an unfixed cable, and (4) cable storage with a fixed cable. Results. We found statistically significant differences in the occurrence of maximum amplitude and pressure gain velocity in intracochlear pressure changes under the compared conditions. Comparing the cable storage conditions, a cable fixed mode offers significantly lower maximum pressure amplitude and pressure gain velocity than the nonfixed mode. Conclusion. Postinsertional cable movement led to a significant pressure transfer into the cochlea. Before positioning the electrode cable in the mastoid cavity, fixation of the cable is recommended.

  10. Simultaneous Measurements of Ossicular Velocity and Intracochlear Pressure Leading to the Cochlear Input Impedance in Gerbil

    PubMed Central

    Decraemer, W. F.; Khanna, S. M.; Olson, E. S.

    2008-01-01

    Recent measurements of three-dimensional stapes motion in gerbil indicated that the piston component of stapes motion was the primary contributor to intracochlear pressure. In order to make a detailed correlation between stapes piston motion and intracochlear pressure behind the stapes, simultaneous pressure and motion measurements were undertaken. We found that the scala vestibuli pressure followed the piston component of the stapes velocity with high fidelity, reinforcing our previous finding that the piston motion of the stapes was the main stimulus to the cochlea. The present data allowed us to calculate cochlear input impedance and power flow into the cochlea. Both the amplitude and phase of the impedance were quite flat with frequency from 3 kHz to at least 30 kHz, with a phase that was primarily resistive. With constant stimulus pressure in the ear canal the intracochlear pressure at the stapes has been previously shown to be approximately flat with frequency through a wide range, and coupling that result with the present findings indicates that the power that flows into the cochlea is quite flat from about 3 to 30 kHz. The observed wide-band intracochlear pressure and power flow are consistent with the wide-band audiogram of the gerbil. PMID:18459001

  11. Intracochlear Scala Media Pressure Measurement: Implications for Models of Cochlear Mechanics

    PubMed Central

    Kale, Sushrut S.; Olson, Elizabeth S.

    2015-01-01

    Models of the active cochlea build upon the underlying passive mechanics. Passive cochlear mechanics is based on physical and geometrical properties of the cochlea and the fluid-tissue interaction between the cochlear partition and the surrounding fluid. Although the fluid-tissue interaction between the basilar membrane and the fluid in scala tympani (ST) has been explored in both active and passive cochleae, there was no experimental data on the fluid-tissue interaction on the scala media (SM) side of the partition. To this aim, we measured sound-evoked intracochlear pressure in SM close to the partition using micropressure sensors. All the SM pressure data are from passive cochleae, likely because the SM cochleostomy led to loss of endocochlear potential. Thus, these experiments are studies of passive cochlear mechanics. SM pressure close to the tissue showed a pattern of peaks and notches, which could be explained as an interaction between fast and slow (i.e., traveling wave) pressure modes. In several animals SM and ST pressure were measured in the same cochlea. Similar to previous studies, ST-pressure was dominated by a slow, traveling wave mode at stimulus frequencies in the vicinity of the best frequency of the measurement location, and by a fast mode above best frequency. Antisymmetric pressure between SM and ST supported the classic single-partition cochlear models, or a dual-partition model with tight coupling between partitions. From the SM and ST pressure we calculated slow and fast modes, and from active ST pressure we extrapolated the passive findings to the active case. The passive slow mode estimated from SM and ST data was low-pass in nature, as predicted by cochlear models. PMID:26682824

  12. Intracochlear Scala Media Pressure Measurement: Implications for Models of Cochlear Mechanics.

    PubMed

    Kale, Sushrut S; Olson, Elizabeth S

    2015-12-15

    Models of the active cochlea build upon the underlying passive mechanics. Passive cochlear mechanics is based on physical and geometrical properties of the cochlea and the fluid-tissue interaction between the cochlear partition and the surrounding fluid. Although the fluid-tissue interaction between the basilar membrane and the fluid in scala tympani (ST) has been explored in both active and passive cochleae, there was no experimental data on the fluid-tissue interaction on the scala media (SM) side of the partition. To this aim, we measured sound-evoked intracochlear pressure in SM close to the partition using micropressure sensors. All the SM pressure data are from passive cochleae, likely because the SM cochleostomy led to loss of endocochlear potential. Thus, these experiments are studies of passive cochlear mechanics. SM pressure close to the tissue showed a pattern of peaks and notches, which could be explained as an interaction between fast and slow (i.e., traveling wave) pressure modes. In several animals SM and ST pressure were measured in the same cochlea. Similar to previous studies, ST-pressure was dominated by a slow, traveling wave mode at stimulus frequencies in the vicinity of the best frequency of the measurement location, and by a fast mode above best frequency. Antisymmetric pressure between SM and ST supported the classic single-partition cochlear models, or a dual-partition model with tight coupling between partitions. From the SM and ST pressure we calculated slow and fast modes, and from active ST pressure we extrapolated the passive findings to the active case. The passive slow mode estimated from SM and ST data was low-pass in nature, as predicted by cochlear models.

  13. Simultaneous Intracochlear Pressure Measurements from Two Cochlear Locations: Propagation of Distortion Products in Gerbil.

    PubMed

    Dong, Wei

    2016-12-01

    Sound energy propagates in the cochlea through a forward-traveling or slow wave supported by the cochlear partition and fluid inertia. Additionally, cochlear models support traveling wave propagation in the reverse direction as the expected mechanism for conveying otoacoustic emissions out of the cochlea. Recently, however, this hypothesis has been questioned, casting doubt on the process by which otoacoustic emissions travel back out through the cochlea. The proposed alternative reverse travel path for emissions is directly through the fluids of the cochlea as a compression pressure in the form of a fast wave. In the present study, a custom-made micro-pressure sensor was used in vivo in the gerbil cochlea to map two-tone-evoked pressure responses at distinct longitudinal and vertical locations in both the scala tympani and scala vestibuli. Analyses of the magnitude and phase of intracochlear pressure responses at the primary tone and distortion product frequencies were used to distinguish between fast and slow waves in both the forward- and reverse-propagation directions. Results demonstrated that distortion products may travel in both forward and reverse directions post-generation and the existence of both traveling and compression waves. The forward-traveling component appeared to duplicate the process of any external tone, tuned to the local characteristic-frequency place, as it increased compressively and nonlinearly with primary-tone levels. A compression wave was evidenced at frequencies above the cutoff of the recording site. In the opposite direction, a reverse-traveling wave played the major role in driving the stapes reversely and contributed to the distortion product otoacoustic emission. The compression wave may also play a role in reverse propagation when distortion products are generated at a region close to the stapes.

  14. A family of fiber-optic based pressure sensors for intracochlear measurements

    NASA Astrophysics Data System (ADS)

    Olson, Elizabeth S.; Nakajima, Hideko H.

    2015-02-01

    Fiber-optic pressure sensors have been developed for measurements of intracochlear pressure. The present family of transducers includes an 81 μm diameter sensor employing a SLED light source and single-mode optic fiber, and LED/multi-mode sensors with 126 and 202 μm diameter. The 126 μm diameter pressure sensor also has been constructed with an electrode adhered to its side, for coincident pressure and voltage measurements. These sensors have been used for quantifying cochlear mechanical impedances, informing our understanding of conductive hearing loss and its remediation, and probing the operation of the cochlear amplifier.

  15. Optimisation of the round window opening in cochlear implant surgery in wet and dry conditions: impact on intracochlear pressure changes.

    PubMed

    Mittmann, Philipp; Ernst, A; Mittmann, M; Todt, I

    2016-11-01

    To preserve residual hearing in cochlear implant candidates, the atraumatic insertion of the cochlea electrode has become a focus of cochlea implant research. In a previous study, intracochlear pressure changes during the opening of the round window membrane were investigated. In the current study, intracochlear pressure changes during opening of the round window membrane under dry and transfluid conditions were investigated. Round window openings were performed in an artificial cochlear model. Intracochlear pressure changes were measured using a micro-optical pressure sensor, which was placed in the apex. Openings of the round window membrane were performed under dry and wet conditions using a cannula and a diode laser. Statistically significant differences in the intracochlear pressure changes were seen between the different methods used for opening of the round window membrane. Lower pressure changes were seen by opening the round window membrane with the diode laser than with the cannula. A significant difference was seen between the dry and wet conditions. The atraumatic approach to the cochlea is assumed to be essential for the preservation of residual hearing. Opening of the round window under wet conditions produce a significant advantage on intracochlear pressure changes in comparison to dry conditions by limiting negative outward pressure.

  16. [Pressure relations between endocranial and intracochlear fluid spaces in patients with inner ear diseases].

    PubMed

    Gosepath, K; Maurer, J; Pelster, H; Thews, O; Mann, W

    1995-03-01

    Intracranial pressure is transmitted to the perilymph of the cochlea via the cochlear aquaeduct and via Reissner's membrane to the endolymph. The "Tympanic Membrane Displacement Analyser (TDA)" is a new device that may be a useful non-invasive method to show intracranial and intracochlear pressure changes indirectly measured by tympanic membrane displacement during stapedial reflex contraction. The TDA was utilised in 20 normal persons and in 29 patients with unilateral diseases of the inner ear. No significant differences in the tympanic membrane displacement were found between patients with sensorineural hearing loss, patients with Ménière's disease, and normal persons.

  17. Intracochlear pressure measurements in scala media inform models of cochlear mechanics

    NASA Astrophysics Data System (ADS)

    Kale, Sushrut; Olson, Elizabeth S.

    2015-12-01

    In the classic view of cochlear mechanics, the cochlea is comprised of two identical fluid chambers separated by the cochlear partition (CP). In this view the traveling wave pressures in the two chambers mirror each other; they are equal in magnitude and opposite in phase. A fast pressure mode adds approximately uniformly. More recent models of cochlear mechanics take into account the structural complexity of the CP and the resulting additional mechanical modes would lead to distinct (non-symmetric) patterns of pressure and motion on the two sides of the CP. However, there was little to no physiological data that explored these predictions. To this aim, we measured intracochlear fluid pressure in scala media (SM), including measurements close to the sensory tissue, using miniaturized pressure sensors (˜ 80 μm outer diameter). Measurements were made in-vivo from the basal cochlear turn in gerbils. SM pressure was measured at two longitudinal locations in different preparations. In a subset of the experiments SM and ST (scala tympani) pressures were measured at the same longitudinal location. Traveling wave pressures were observed in both SM and ST, and showed the relative phase predicted by the classical theory. In addition, SM pressure showed spatial variations that had not been observed in ST, which points to a relatively complex CP motion on the SM side. These data both underscore the first-order validity of the classic cochlear traveling wave model, and open a new view to CP mechanics.

  18. Monopolar intracochlear pulse trains selectively activate the inferior colliculus.

    PubMed

    Schoenecker, Matthew C; Bonham, Ben H; Stakhovskaya, Olga A; Snyder, Russell L; Leake, Patricia A

    2012-10-01

    Previous cochlear implant studies using isolated electrical stimulus pulses in animal models have reported that intracochlear monopolar stimulus configurations elicit broad extents of neuronal activation within the central auditory system-much broader than the activation patterns produced by bipolar electrode pairs or acoustic tones. However, psychophysical and speech reception studies that use sustained pulse trains do not show clear performance differences for monopolar versus bipolar configurations. To test whether monopolar intracochlear stimulation can produce selective activation of the inferior colliculus, we measured activation widths along the tonotopic axis of the inferior colliculus for acoustic tones and 1,000-pulse/s electrical pulse trains in guinea pigs and cats. Electrical pulse trains were presented using an array of 6-12 stimulating electrodes distributed longitudinally on a space-filling silicone carrier positioned in the scala tympani of the cochlea. We found that for monopolar, bipolar, and acoustic stimuli, activation widths were significantly narrower for sustained responses than for the transient response to the stimulus onset. Furthermore, monopolar and bipolar stimuli elicited similar activation widths when compared at stimulus levels that produced similar peak spike rates. Surprisingly, we found that in guinea pigs, monopolar and bipolar stimuli produced narrower sustained activation than 60 dB sound pressure level acoustic tones when compared at stimulus levels that produced similar peak spike rates. Therefore, we conclude that intracochlear electrical stimulation using monopolar pulse trains can produce activation patterns that are at least as selective as bipolar or acoustic stimulation.

  19. 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.

  20. 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.

  1. 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.

  2. Sound pressure level in a municipal preschool

    PubMed Central

    Kemp, Adriana Aparecida Tahara; Delecrode, Camila Ribas; Guida, Heraldo Lorena; Ribeiro, André Knap; Cardoso, Ana Claúdia Vieira

    2013-01-01

    Summary Aim: To evaluate the sound pressure level to which preschool students are exposed. Method: This was a prospective, quantitative, nonexperimental, and descriptive study. To achieve the aim of the study we used an audio dosimeter. The sound pressure level (SPL) measurements were obtained for 2 age based classrooms. Preschool I and II. The measurements were obtained over 4 days in 8-hour sessions, totaling 1920 minutes. Results: Compared with established standards, the SPL measured ranged from 40.6 dB (A) to 105.8 dB (A). The frequency spectrum of the SPL was concentrated in the frequency range between 500 Hz and 4000 Hz. The older children produced higher SPLs than the younger ones, and the levels varied according to the activity performed. Painting and writing were the quietest activities, while free activities period and games were the noisiest. Conclusion: The SPLs measured at the preschool were higher and exceeded the maximum permitted level according to the reference standards. Therefore, the implementation of actions that aim to minimize the negative impact of noise in this environment is essential. PMID:25992013

  3. 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.

  4. Intracochlear schwannoma: diagnosis and management.

    PubMed

    Bittencourt, Aline Gomes; Alves, Ricardo Dourado; Ikari, Liliane Satomi; Burke, Patrick Rademaker; Gebrim, Eloisa Maria Santiago; Bento, Ricardo Ferreira

    2014-07-01

    Introduction Schwannomas of the eighth cranial nerve are benign tumors that usually occur in the internal auditory canal or the cerebellopontine angle cistern. Rarely, these tumors may originate from the neural elements within the vestibule, cochlea, or semicircular canals and are called intralabyrinthine schwannomas. Intracochlear schwannomas (ICSs) represent a small percentage of these tumors, and their diagnosis is based on high-resolution magnetic resonance imaging (MRI). Objectives To report the clinical and radiologic features and audiometric testing results of an ICS in a 48-year-old man after a 22-month follow-up period. Resumed Report A patient with an 8-year history of persistent tinnitus in his right ear, combined with ipsilateral progressive hearing loss and aural fullness. Audiometry revealed normal hearing in the left ear and a moderate to severe sensorineural hearing loss in the right ear, with decreased speech reception threshold and word recognition score, compared with the exam performed 5 years previously. MRI showed a small intracochlear nodular lesion in the modiolus, isointense on T1 with a high contrast enhancement on T1 postgadolinium images. During the follow-up period, there were no radiologic changes on imaging studies. Thus, a wait-and-scan policy was chosen as the lesion remained stable with no considerable growth and the patient still presents with residual hearing. Conclusions Once diagnosed, not all ICS patients require surgery. Treatment options for ICS include stereotactic radiotherapy and rescanning policy, depending on the tumor's size, evidence of the tumor's growth, degree of hearing loss, intractable vestibular symptoms, concern about the pathologic diagnosis, and the patient's other medical conditions.

  5. Implantable micropump technologies for murine intracochlear infusions.

    PubMed

    Johnson, D G; Waldron, M J; Frisina, R D; Borkholder, D A

    2010-01-01

    Due to the very small size of the mouse inner ear, 600 nL volume, developing effective, controlled infusion systems is quite challenging. Key technologies have been created to minimize both size and power for an implantable pump for murine intracochlear infusions. A method for coupling fine capillary tubing to microfluidic channels is presented which provides low volume, biocompatible interconnects withstanding pressures as high as 827 kPa (120 psi) and consuming less than 20 nL of volume exiting in-plane with the pump. Surface micromachined resistive bridges integrated into the flow channel for anemometry based flow rate measurement have been optimized for low power operation in the ultra-low flow rate regime. A process for creation of deformable diaphragms over pump chambers with simultaneous coating of the microfluidic channels has been developed allowing integration of a biocompatible fluid flow path. These advances represent enabling capabilities for a drug delivery system suitable for space constrained applications such as subcutaneous implantation in mice.

  6. Implantable Micropump Technologies for Murine Intracochlear Infusions

    PubMed Central

    Johnson, D. G.; Waldron, M. J.; Frisina, R. D.; Borkholder, D. A.

    2011-01-01

    Due to the very small size of the mouse inner ear, 600 nL volume, developing effective, controlled infusion systems is quite challenging. Key technologies have been created to minimize both size and power for an implantable pump for murine intracochlear infusions. A method for coupling fine capillary tubing to microfluidic channels is presented which provides low volume, biocompatible interconnects withstanding pressures as high as 827 kPa (120 psi) and consuming less than 20 nL of volume exiting in-plane with the pump. Surface micromachined resistive bridges integrated into the flow channel for anemometry based flow rate measurement have been optimized for low power operation in the ultra-low flow rate regime. A process for creation of deformable diaphragms over pump chambers with simultaneous coating of the microfluidic channels has been developed allowing integration of a biocompatible fluid flow path. These advances represent enabling capabilities for a drug delivery system suitable for space constrained applications such as subcutaneous implantation in mice. PMID:21096713

  7. Automatic segmentation of intra-cochlear anatomy in post-implantation CT

    NASA Astrophysics Data System (ADS)

    Reda, Fitsum A.; Dawant, Benoit M.; McRackan, Theodore R.; Labadie, Robert F.; Noble, Jack H.

    2013-03-01

    A cochlear implant (CI) is a neural prosthetic device that restores hearing by directly stimulating the auditory nerve with an electrode array. In CI surgery, the surgeon threads the electrode array into the cochlea, blind to internal structures. We have recently developed algorithms for determining the position of CI electrodes relative to intra-cochlear anatomy using pre- and post-implantation CT. We are currently using this approach to develop a CI programming assistance system that uses knowledge of electrode position to determine a patient-customized CI sound processing strategy. However, this approach cannot be used for the majority of CI users because the cochlea is obscured by image artifacts produced by CI electrodes and acquisition of pre-implantation CT is not universal. In this study we propose an approach that extends our techniques so that intra-cochlear anatomy can be segmented for CI users for which pre-implantation CT was not acquired. The approach achieves automatic segmentation of intra-cochlear anatomy in post-implantation CT by exploiting intra-subject symmetry in cochlear anatomy across ears. We validated our approach on a dataset of 10 ears in which both pre- and post-implantation CTs were available. Our approach results in mean and maximum segmentation errors of 0.27 and 0.62 mm, respectively. This result suggests that our automatic segmentation approach is accurate enough for developing customized CI sound processing strategies for unilateral CI patients based solely on postimplantation CT scans.

  8. Tinnitus Suppression by Intracochlear Electrical Stimulation in Single Sided Deafness – A Prospective Clinical Trial: Follow-Up

    PubMed Central

    Arts, Remo A. G. J.; George, Erwin L. J.; Janssen, Miranda; Griessner, Andreas; Zierhofer, Clemens; Stokroos, Robert J.

    2016-01-01

    Introduction Earlier studies show that a Cochlear Implant (CI), capable of providing intracochlear electrical stimulation independent of environmental sounds, appears to suppress tinnitus at least for minutes. The current main objective is to compare the long-term suppressive effects of looped (i.e. repeated) electrical stimulation (without environmental sound perception) with the standard stimulation pattern of a CI (with environmental sound perception). This could open new possibilities for the development of a “Tinnitus Implant” (TI), an intracochlear pulse generator for the suppression of tinnitus. Materials and Methods Ten patients with single sided deafness suffering from unilateral tinnitus in the deaf ear are fitted with a CI (MED-EL Corporation, Innsbruck, Austria). Stimulation patterns are optimized for each individual patient, after which they are compared using a randomized crossover design, with a follow-up of six months, followed by a 3 month period using the modality of patient’s choice. Results Results show that tinnitus can be suppressed with intracochlear electrical stimulation independent of environmental sounds, even long term. No significant difference in tinnitus suppression was found between the standard clinical CI and the TI. Conclusion It can be concluded that coding of environmental sounds is no requirement for tinnitus suppression with intracochlear electrical stimulation. It is therefore plausible that tinnitus suppression by CI is not solely caused by an attention shift from the tinnitus to environmental sounds. Both the standard clinical CI and the experimental TI are potential treatment options for tinnitus. These findings offer perspectives for a successful clinical application of the TI, possibly even in patients with significant residual hearing. Trial Registration TrialRegister.nl NTR3374 PMID:27111333

  9. 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…

  10. 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.

  11. Microflora of Retained Intracochlear Electrodes from Infected Cochlear Implants.

    PubMed

    Varadarajan, Varun V; Dirain, Carolyn O; Antonelli, Patrick J

    2017-02-01

    Objectives Cochlear implant infections may be refractory to medical management and require device removal with subsequent reimplantation. During device removal, the intracochlear electrode array is commonly left in place to prevent obliteration of the cochlear lumen. If the electrode is colonized with pathogens, this risks contaminating the replacement implant. In this study, we compare the microorganisms detected on infected cochlear implants against those on the retained electrode using culture and microbial gene-sequencing techniques. Study Design Prospective single-cohort study. Setting Tertiary medical center. Subjects and Methods Six patients with refractory cochlear implant infections had the receiver-stimulator and extracochlear electrode removed to facilitate treatment of the infection. The intracochlear electrode was removed at (delayed) reimplantation. Implant specimens were analyzed by microbial culture and 16S DNA gene sequencing. Results Staphylococcus aureus was the organism most commonly identified. None of the 6 patients' intracochlear electrodes yielded microbes by culture. Two intracochlear electrodes revealed bacterial species, and 1 revealed fungal species by gene sequencing. There was no correlation between the microbes on the infected extracochlear implants and the retained intracochlear electrodes. All subjects underwent reimplantation after resolution of their infections. One of 6 subjects developed a second infection after reimplantation, with S aureus in the primary and secondary infections. Conclusions The intracochlear electrodes of infected cochlear implants carry a low microbial burden. Preserving intracochlear electrodes upon removal of infected cochlear implants appears to carry a low risk of contaminating a replacement cochlear implant.

  12. 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.

  13. Intracochlear drug injections through the round window membrane: Measures to improve drug retention

    PubMed Central

    Plontke, Stefan K.; Hartsock, Jared J.; Gill, Ruth M.; Salt, Alec N.

    2016-01-01

    The goal of this study was to develop appropriate methodology to apply drugs quantitatively to perilymph of the ear. Intratympanic applications of drugs to the inner ear often result in variable drug levels in perilymph and can only be used for molecules that readily permeate the round window (RW) membrane. Direct intracochlear and intralabyrinthine application procedures for drugs, genes or cell-based therapies by-pass the tight boundaries at the round window, oval window, otic capsule and the blood-labyrinth barrier. However, perforations can release inner ear pressure, allowing cerebrospinal fluid to enter through the cochlear aqueduct, displacing the injected drug solution into the middle ear. Two markers, fluorescein or fluorescein isothiocyanate (FITC)-labeled dextran, were used to quantify how much of an injected substance was retained in cochlear perilymph following an intracochlear injection. We evaluated whether procedures to mitigate fluid leaks improved marker retention in perilymph. Almost all procedures to reduce volume efflux, including the use of gel for internal sealing and glue for external sealing of the injection site, resulted in improved retention of the marker in perilymph. Adhesive on the RW membrane effectively prevented leaks but also influenced fluid exchange between CSF and perilymph. We conclude that drugs can be delivered to the ear in a consistent, quantitative manner using intracochlear injections if care is taken to control the fluid leaks that result from cochlear perforation. PMID:26905306

  14. 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... ENFORCEMENT REGULATIONS § 1500.47 Method for determining the sound pressure level produced by toy caps. (a... of the explosive. Measure the peak sound pressure level at each of the six designated orientations...

  15. 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

  16. 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.

  17. Intracochlear and extracochlear ECAPs suggest antidromic action potentials.

    PubMed

    Miller, Charles A; Abbas, Paul J; Hay-McCutcheon, Marcia J; Robinson, Barbara K; Nourski, Kirill V; Jeng, Fuh-Cherng

    2004-12-01

    With experimental animals, the electrically evoked compound action potential (ECAP) can be recorded from multiple sites (e.g., round window, intracranial and intracochlear sites). However, human ECAPs are typically recorded from intracochlear electrodes of the implanted array. To bridge this difference, we obtained ECAPs from cats using both intracochlear and nerve-trunk recording sites. We also sought to determine how recording the site influences the acquired evoked potential and how those differences may provide insight into basic excitation properties. In the main experiment, ECAPs were recorded from four acutely deafened cats after implanting a Nucleus-style banded electrode array. Potentials were recorded from an electrode positioned on the nerve trunk and an intracochlear electrode. We manipulated stimulus level, electrode configuration (monopolar vs bipolar) and stimulus polarity, variables that influence the site of excitation. Intracochlear ECAPs were found to be an order of magnitude greater than those obtained with the nerve-trunk electrode. Also, compared with the nerve-trunk potentials, the intracochlear ECAPs more closely resembled those obtained from humans in that latencies were shorter and the waveform morphology was typically biphasic (a negative peak followed by a positive peak). With anodic monophasic stimuli, the ECAP had a unique positive-to-negative morphology which we attributed to antidromic action potentials resulting from a relatively central site of excitation. We also collected intracochlear ECAPs from twenty Nucleus 24 implant users. Compared with the feline ECAPs, the human potentials had smaller amplitudes and longer latencies. It is not clear what underlies these differences, although several factors are considered.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. Modeling of sound transmission from ear canal to cochlea.

    PubMed

    Gan, Rong Z; Reeves, Brian P; Wang, Xuelin

    2007-12-01

    A 3-D finite element (FE) model of the human ear consisting of the external ear canal, middle ear, and cochlea is reported in this paper. The acoustic-structure-fluid coupled FE analysis was conducted on the model which included the air in the ear canal and middle ear cavity, the fluid in the cochlea, and the middle ear and cochlea structures (i.e., bones and soft tissues). The middle ear transfer function such as the movements of tympanic membrane, stapes footplate, and round window, the sound pressure gain across the middle ear, and the cochlear input impedance in response to sound stimulus applied in the ear canal were derived and compared with the published experimental measurements in human temporal bones. The frequency sensitivity of the basilar membrane motion and intracochlear pressure induced by sound pressure in the ear canal was predicted along the length of the basilar membrane from the basal turn to the apex. The satisfactory agreements between the model and experimental data in the literature indicate that the middle ear function was well simulated by the model and the simplified cochlea was able to correlate sound stimulus in the ear canal with vibration of the basilar membrane and pressure variation of the cochlear fluid. This study is the first step toward the development of a comprehensive FE model of the entire human ear for acoustic-mechanical analysis.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Highly Flexible Silicone Coated Neural Array for Intracochlear Electrical Stimulation

    PubMed Central

    Bhatti, P.; Van Beek-King, J.; Sharpe, A.; Crawford, J.; Tridandapani, S.; McKinnon, B.; Blake, D.

    2015-01-01

    We present an effective method for tailoring the flexibility of a commercial thin-film polymer electrode array for intracochlear electrical stimulation. Using a pneumatically driven dispensing system, an average 232 ± 64 μm (mean ± SD) thickness layer of silicone adhesive coating was applied to stiffen the underside of polyimide multisite arrays. Additional silicone was applied to the tip to protect neural tissue during insertion and along the array to improve surgical handling. Each array supported 20 platinum sites (180 μm dia., 250 μm pitch), spanning nearly 28 mm in length and 400 μm in width. We report an average intracochlear stimulating current threshold of 170 ± 93 μA to evoke an auditory brainstem response in 7 acutely deafened felines. A total of 10 arrays were each inserted through a round window approach into the cochlea's basal turn of eight felines with one delamination occurring upon insertion (preliminary results of the in vivo data presented at the 48th Annual Meeting American Neurotology Society, Orlando, FL, April 2013, and reported in Van Beek-King 2014). Using microcomputed tomography imaging (50 μm resolution), distances ranging from 100 to 565 μm from the cochlea's central modiolus were measured. Our method combines the utility of readily available commercial devices with a straightforward postprocessing step on the order of 24 hours. PMID:26236714

  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. 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.

  4. Pressures in the human cochlea during bone conduction

    NASA Astrophysics Data System (ADS)

    Stieger, Christof; Farahmand, Rosemary B.; Page, Brent F.; Roushan, Kourosh; Merchant, Julie P.; Abur, Defne; Rosowski, John J.; Nakajima, Hideko Heidi

    2015-12-01

    The mechanisms of bone conduction (BC) hearing, which is important in diagnosis and treatment of hearing loss, are poorly understood, thus limiting use of BC. Recently, information gained by intracochlear pressure measurements has revealed that the mechanisms of sound transmission that drive pressure differences across the cochlear partition are different for air conduction (AC) than for round-window stimulation. Presently we are utilizing these pressure measurement techniques in fresh human cadaveric preparations to improve our understanding of sound transmission during BC. We have modified our technique of intracochlear pressure measurements for the special requirements of studying BC, as bone vibration poses challenges for making these measurements. Fiberoptic pressure sensors were inserted through cochleostomies in both scalae at the base of the cochlea. The cochleostomies were then tightly sealed with the sensors in place to prevent air and fluid leaks, and the sensors were firmly secured to ensure uniform vibrations of the sensors and surrounding bone of the cochlea. The velocity of the stapes, round window and cochlear promontory were each measured with laser Doppler vibrometry simultaneous to the intracochlear pressure measurements. To understand the contribution of middle-ear inertia, the incudo-stapedial joint was severed. Subsequently, the stapes footplate was fixed (similar to the consequence of otosclerosis) to determine the effect of removing the mobility of the oval window. BC stimulation resulted in pressure in scala vestibuli that was significantly higher than in scala tympani, such that the differential pressure across the partition - the cochlear drive input - was similar to scala vestibuli pressure (and overall, similar to the relationship found during AC but different than during round-window stimulation). After removing the inertial mass of the middle ear, with only the stapes attached to the flexible oval window, all pressures dropped

  5. 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.

  6. 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.

  7. 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.

  8. Comparing Distortion Product Otoacoustic Emissions to Intracochlear Distortion Products Inferred from a Noninvasive Assay.

    PubMed

    Martin, Glen K; Stagner, Barden B; Dong, Wei; Lonsbury-Martin, Brenda L

    2016-08-01

    The behavior of intracochlear distortion products (iDPs) was inferred by interacting a probe tone (f3) with the iDP of interest to produce a "secondary" distortion product otoacoustic emission termed DPOAE(2ry). Measures of the DPOAE(2ry) were then used to deduce the properties of the iDP. This approach was used in alert rabbits and anesthetized gerbils to compare ear-canal 2f1-f2 and 2f2-f1 DPOAE f2/f1 ratio functions, level/phase (L/P) maps, and interference-response areas (IRAs) to their simultaneously collected DPOAE(2ry) counterparts. These same measures were also collected in a human volunteer to demonstrate similarities with their laboratory animal counterparts and their potential applicability to humans. Results showed that DPOAEs and inferred iDPs evidenced distinct behaviors and properties. That is, DPOAE ratio functions elicited by low-level primaries peaked around an f2/f1 = 1.21 or 1.25, depending on species, while the corresponding inferred iDP ratio functions peaked at f2/f1 ratios of ~1. Additionally, L/P maps showed rapid phase variation with DPOAE frequency (fdp) for the narrow-ratio 2f1-f2 and all 2f2-f1 DPOAEs, while the corresponding DPOAE(2ry) measures evidenced relatively constant phases. Common features of narrow-ratio DPOAE IRAs, such as large enhancements for interference tones (ITs) presented above f2, were not present in DPOAE(2ry) IRAs. Finally, based on prior experiments in gerbils, the behavior of the iDP directly measured in intracochlear pressure was compared to the iDP inferred from the DPOAE(2ry) and found to be similar. Together, these findings are consistent with the notion that under certain conditions, ear-canal DPOAEs provide poor representations of iDPs and thus support a "beamforming" hypothesis. According to this concept, distributed emission components directed toward the ear canal from the f2 and basal to f2 regions can be of differing phases and thus cancel, while these same components directed toward fdp add in

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Minimally Invasive Surgery for Intracochlear Schwannoma Removal and Simultaneous Cochlear Implantation

    PubMed Central

    Bento, Ricardo Ferreira; Gebrim, Eloisa Maria Mello Santiago; Magalhães, Ana Tereza de Matos; Pereira, Larissa Vilela; Fonseca, Anna Carolina de Oliveira

    2016-01-01

    Introduction  Hearing preservation has not yet been reported in patients undergoing resection of intracochlear schwannomas. This study describes a minimally invasive procedure for intracochlear schwannoma resection with simultaneous cochlear implantation that resulted in good hearing. Objective  This study aims to describe a minimally invasive procedure for intracochlear schwannoma resection with simultaneous cochlear implantation. Data Synthesis  The technique described in this study was developed for a 55-year-old male with a 20-year history of bilateral progressive hearing loss and tinnitus that had a mass in the left apical turn of the cochlea measuring 0.3 cm. Surgery accessed the apical turn of the cochlea. We performed mastoidectomy and posterior tympanotomy and removed incus and tensor tympani muscle to expose the cochlear apex. The tumor was identified and completely resected. After the cochlea was anatomically preserved, it was implanted with a straight electrode via round window insertion. The histopathological examination confirmed intracochlear schwannoma. Speech perception test revealed 100% speech recognition with closed sentences and the average audiometric threshold (500 to 2000 Hz) was 23 dB. Conclusion  Our technique led to rehabilitation of the patient and improved hearing without damaging the intracochlear structure, making it possible to perform CI in the same procedure with good results. PMID:27413411

  19. Intracochlear drug delivery in combination with cochlear implants : Current aspects.

    PubMed

    Plontke, S K; Götze, G; Rahne, T; Liebau, A

    2017-01-01

    Local drug application to the inner ear offers a number of advantages over systemic delivery. Local drug therapy currently encompasses extracochlear administration (i. e., through intratympanic injection), intracochlear administration (particularly for gene and stem cell therapy), as well as various combinations with auditory neurosensory prostheses, either evaluated in preclinical or clinical studies, or off-label. To improve rehabilitation with cochlear implants (CI), one focus is the development of drug-releasing electrode carriers, e. g., for delivery of glucocorticosteroids, antiapoptotic substances, or neurotrophins to the inner ear. The performance of cochlear implants may thus be improved by protecting neuronal structures from insertion trauma, reducing fibrosis in the inner ear, and by stimulating growth of neuronal structures in the direction of the electrodes. Controlled drug release after extracochlear or intracochlear application in conjunction with a CI can also be achieved by use of a biocompatible, resorbable controlled-release drug-delivery system. Two case reports for intracochlear controlled release drug delivery in combination with cochlear implants are presented. In order to treat progressive reduction in speech discrimination and increased impedance, two cochlear implant patients successfully underwent intracochlear placement of a biocompatible, resorbable drug-delivery system for controlled release of dexamethasone. The drug levels reached in inner ear fluids after different types of local drug application strategies can be calculated using a computer model. The intracochlear drug concentrations calculated in this way were compared for different dexamethasone application strategies.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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…

  7. Comparison of forward (ear-canal) and reverse (round-window) sound stimulation of the cochlea

    PubMed Central

    Stieger, Christof; Rosowski, John J.; Nakajima, Hideko Heidi

    2012-01-01

    The cochlea is normally driven with “forward” stimulation, in which sound is introduced to the ear canal. Alternatively, the cochlea can be stimulated at the round window (RW) using an actuator. During RW “reverse” stimulation, the acoustic flow starting at the RW does not necessarily take the same path as during forward stimulation. To understand the differences between forward and reverse stimulation, we measured ear-canal pressure, stapes velocity, RW velocity, and intracochlear pressures in scala vestibuli (SV) and scala tympani (ST) of fresh human temporal bones. During forward stimulation, the cochlear drive (differential pressure across the partition) results from the large difference in magnitude between the pressures of SV and ST, which occurs due to the high compliance of the RW. During reverse stimulation, the relatively high impedance of the middle ear causes the pressures of SV and ST to have similar magnitudes, and the differential pressure results primarily from the difference in phase of the pressures. Furthermore, the sound path differs between forward and reverse stimulation, such that motion through a third window is more significant during reverse stimulation. Additionally, we determined that although stapes velocity is a good estimate of cochlear drive during forward stimulation, it is not a good measure during reverse stimulation. PMID:23159918

  8. Comparison of forward (ear-canal) and reverse (round-window) sound stimulation of the cochlea.

    PubMed

    Stieger, Christof; Rosowski, John J; Nakajima, Hideko Heidi

    2013-07-01

    The cochlea is normally driven with "forward" stimulation, in which sound is introduced to the ear canal. Alternatively, the cochlea can be stimulated at the round window (RW) using an actuator. During RW "reverse" stimulation, the acoustic flow starting at the RW does not necessarily take the same path as during forward stimulation. To understand the differences between forward and reverse stimulation, we measured ear-canal pressure, stapes velocity, RW velocity, and intracochlear pressures in scala vestibuli (SV) and scala tympani (ST) of fresh human temporal bones. During forward stimulation, the cochlear drive (differential pressure across the partition) results from the large difference in magnitude between the pressures of SV and ST, which occurs due to the high compliance of the RW. During reverse stimulation, the relatively high impedance of the middle ear causes the pressures of SV and ST to have similar magnitudes, and the differential pressure results primarily from the difference in phase of the pressures. Furthermore, the sound path differs between forward and reverse stimulation, such that motion through a third window is more significant during reverse stimulation. Additionally, we determined that although stapes velocity is a good estimate of cochlear drive during forward stimulation, it is not a good measure during reverse stimulation. This article is part of a special issue entitled "MEMRO 2012".

  9. Direct Intracochlear Acoustic Stimulation Using a PZT Microactuator.

    PubMed

    Luo, Chuan; Omelchenko, Irina; Manson, Robert; Robbins, Carol; Oesterle, Elizabeth C; Cao, Guo Zhong; Shen, I Y; Hume, Clifford R

    2015-12-01

    Combined electric and acoustic stimulation has proven to be an effective strategy to improve hearing in some cochlear implant users. We describe an acoustic microactuator to directly deliver stimuli to the perilymph in the scala tympani. The 800 µm by 800 µm actuator has a silicon diaphragm driven by a piezoelectric thin film (e.g., lead-zirconium-titanium oxide or PZT). This device could also be used as a component of a bimodal acoustic-electric electrode array. In the current study, we established a guinea pig model to test the actuator for its ability to deliver auditory signals to the cochlea in vivo. The actuator was placed through the round window of the cochlea. Auditory brainstem response (ABR) thresholds, peak latencies, and amplitude growth were calculated for an ear canal speaker versus the intracochlear actuator for tone burst stimuli at 4, 8, 16, and 24 kHz. An ABR was obtained after removal of the probe to assess loss of hearing related to the procedure. In some animals, the temporal bone was harvested for histologic analysis of cochlear damage. We show that the device is capable of stimulating ABRs in vivo with latencies and growth functions comparable to stimulation in the ear canal. Further experiments will be necessary to evaluate the efficiency and safety of this modality in long-term auditory stimulation and its ability to be integrated with conventional cochlear implant arrays.

  10. Direct Intracochlear Acoustic Stimulation Using a PZT Microactuator

    PubMed Central

    Luo, Chuan; Omelchenko, Irina; Manson, Robert; Robbins, Carol; Oesterle, Elizabeth C.; Cao, Guo Zhong; Hume, Clifford R.

    2015-01-01

    Combined electric and acoustic stimulation has proven to be an effective strategy to improve hearing in some cochlear implant users. We describe an acoustic microactuator to directly deliver stimuli to the perilymph in the scala tympani. The 800 µm by 800 µm actuator has a silicon diaphragm driven by a piezoelectric thin film (e.g., lead-zirconium-titanium oxide or PZT). This device could also be used as a component of a bimodal acoustic-electric electrode array. In the current study, we established a guinea pig model to test the actuator for its ability to deliver auditory signals to the cochlea in vivo. The actuator was placed through the round window of the cochlea. Auditory brainstem response (ABR) thresholds, peak latencies, and amplitude growth were calculated for an ear canal speaker versus the intracochlear actuator for tone burst stimuli at 4, 8, 16, and 24 kHz. An ABR was obtained after removal of the probe to assess loss of hearing related to the procedure. In some animals, the temporal bone was harvested for histologic analysis of cochlear damage. We show that the device is capable of stimulating ABRs in vivo with latencies and growth functions comparable to stimulation in the ear canal. Further experiments will be necessary to evaluate the efficiency and safety of this modality in long-term auditory stimulation and its ability to be integrated with conventional cochlear implant arrays. PMID:26631107

  11. 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

  12. 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.

  13. 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.

  14. Acoustic schwannoma with intracochlear extension and primary intracochlear schwannoma: removal through translabyrinthine approach with facial bridge cochleostomy and transcanal approach.

    PubMed

    Mazzoni, A; Zanoletti, E; Faccioli, C; Martini, A

    2017-02-27

    Intracochlear schwannomas can occur either as an extension of a larger tumor from the internal auditory canal, or as a solitary labyrinthine tumor. They are currently removed via a translabyrinthine approach extended to the basal turn, adding a transotic approach for tumors lying beyond the basal turn. Facial bridge cochleostomy may be associated with the translabyrinthine approach to enable the whole cochlea to be approached without sacrificing the external auditory canal and tympanum. We describe seven cases, five of which underwent cochlear schwannoma resection with facial bridge cochleostomy, one case with the same procedure for a suspect tumor and one, previously subjected to radical tympanomastoidectomy, who underwent schwannoma resection via a transotic approach. Facial bridge cochleostomy involved removing the bone between the labyrinthine and tympanic portions of the fallopian canal, and exposing the cochlea from the basal to the apical turn. Patients' recovery was uneventful, and long-term magnetic resonance imaging showed no residual tumor. Facial bridge cochleostomy can be a flexible extension of the translabyrinthine approach for tumors extending from the internal auditory canal to the cochlea. The transcanal approach is suitable for the primary exclusive intralabyrinthine tumor. The indications for the different approaches are discussed.

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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%.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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…

  16. 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…

  17. Effects of sound pressure level and visual perceptual load on the auditory mismatch negativity.

    PubMed

    Szychowska, Malina; Eklund, Rasmus; Nilsson, Mats E; Wiens, Stefan

    2017-02-15

    Auditory change detection has been studied extensively with mismatch negativity (MMN), an event-related potential. Because it is unresolved if the duration MMN depends on sound pressure level (SPL), we studied effects of different SPLs (56, 66, and 76dB) on the duration MMN. Further, previous research suggests that the MMN is reduced by a concurrent visual task. Because a recent behavioral study found that high visual perceptual load strongly reduced detection sensitivity to irrelevant sounds, we studied if the duration MMN is reduced by load, and if this reduction is stronger at low SPLs. Although a duration MMN was observed for all SPLs, the MMN was apparently not moderated strongly by SPL, perceptual load, or their interaction, because all 95% CIs overlapped zero. In a contrast analysis of the MMN (across loads) between the 56-dB and 76-dB groups, evidence (BF=0.31) favored the null hypothesis that duration MMN is unaffected by a 20-dB increase in SPL. Similarly, evidence (BF=0.19) favored the null hypothesis that effects of perceptual load on the duration MMN do not change with a 20-dB increase in SPL. However, evidence (BF=3.12) favored the alternative hypothesis that the effect of perceptual load in the present study resembled the overall effect in a recent meta-analysis. When the present findings were combined with the meta-analysis, the effect of load (low minus high) was -0.43μV, 95% CI [-0.64, -0.22] suggesting that the duration MMN decreases with load. These findings provide support for a sensitive monitoring system of the auditory environment.

  18. Modeling and segmentation of intra-cochlear anatomy in conventional CT

    NASA Astrophysics Data System (ADS)

    Noble, Jack H.; Rutherford, Robert B.; Labadie, Robert F.; Majdani, Omid; Dawant, Benoit M.

    2010-03-01

    Cochlear implant surgery is a procedure performed to treat profound hearing loss. Since the cochlea is not visible in surgery, the physician uses anatomical landmarks to estimate the pose of the cochlea. Research has indicated that implanting the electrode in a particular cavity of the cochlea, the scala tympani, results in better hearing restoration. The success of the scala tympani implantation is largely dependent on the point of entry and angle of electrode insertion. Errors can occur due to the imprecise nature of landmark-based, manual navigation as well as inter-patient variations between scala tympani and the anatomical landmarks. In this work, we use point distribution models of the intra-cochlear anatomy to study the inter-patient variations between the cochlea and the typical anatomic landmarks, and we implement an active shape model technique to automatically localize intra-cochlear anatomy in conventional CT images, where intra-cochlear structures are not visible. This fully automatic segmentation could aid the surgeon to choose the point of entry and angle of approach to maximize the likelihood of scala tympani insertion, resulting in more substantial hearing restoration.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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).

  4. 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

  5. Behavioral responses of deafened guinea pigs to intracochlear electrical stimulation: a new rapid psychophysical procedure.

    PubMed

    Agterberg, Martijn J H; Versnel, Huib

    2014-07-01

    In auditory research the guinea pig is often preferred above rats and mice because of the easily accessible cochlea and because the frequency range of its hearing is more comparable to that of humans. Studies of the guinea-pig auditory system primarily apply histological and electrophysiological measures. Behavioral animal paradigms, in particular in combination with these histological and electrophysiological methods, are necessary in the development of new therapeutic interventions. However, the guinea pig is not considered an attractive animal for behavioral experiments. Therefore, the purpose of this study was to develop a behavioral task suitable for guinea pigs, that can be utilized in cochlear-implant related research. Guinea pigs were trained in a modified shuttle-box in which a stream of air was used as unconditioned stimulus (UCS). A stream of air was preferred over conventionally used methods as electric foot-shocks since it produces less stress, which is a confounding factor in behavioral experiments. Hearing guinea pigs were trained to respond to acoustic stimuli. They responded correctly within only five sessions of ten minutes. The animals maintained their performance four weeks after the right cochlea was implanted with an electrode array. After systemic deafening, the animals responded in the first session immediately to intracochlear electrical stimulation. These responses were not affected by daily chronic electrical stimulation (CES). In conclusion, the present study demonstrates that guinea pigs can be trained relatively fast to respond to acoustic stimuli, and that the training has a lasting effect, which generalizes to intracochlear electrical stimulation after deafening. Furthermore, it demonstrates that bilaterally deafened guinea pigs with substantial (∼50%) loss of spiral ganglion cells (SGCs), detect intracochlear electrical stimulation.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  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. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. [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.

  18. 16 CFR 1500.47 - Method for determining the sound pressure level produced by toy caps.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... used at normal or at grazing incidence, whichever gives the most uniform free-field response. The... accurate to within ±1 decibel. If the calibration is of the pressure type or of the piston-phone plus electrostatic actuator type, it shall be corrected to free-field conditions in accordance with the...

  19. 16 CFR 1500.47 - Method for determining the sound pressure level produced by toy caps.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... used at normal or at grazing incidence, whichever gives the most uniform free-field response. The... accurate to within ±1 decibel. If the calibration is of the pressure type or of the piston-phone plus electrostatic actuator type, it shall be corrected to free-field conditions in accordance with the...

  20. 16 CFR 1500.47 - Method for determining the sound pressure level produced by toy caps.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... used at normal or at grazing incidence, whichever gives the most uniform free-field response. The... accurate to within ±1 decibel. If the calibration is of the pressure type or of the piston-phone plus electrostatic actuator type, it shall be corrected to free-field conditions in accordance with the...

  1. 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…

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Intracochlear Drug Delivery through the Oval Window in Fresh Cadaveric Human Temporal Bones

    PubMed Central

    Kang, Woo Seok; Nguyen, Kim; McKenna, Charles E.; Sewell, William F.; McKenna, Michael J.; Jung, David H.

    2015-01-01

    Hypothesis Drug delivered to the oval window can diffuse to the apex of the human cochlea. Background We have previously demonstrated that zoledronate, a nitrogen-containing bisphosphonate, can arrest the sensorineural hearing loss in cochlear otosclerosis. We have also shown that, in animals, delivery of bisphosphonate into the cochlea can dramatically increase delivery efficiency. Intracochlear drug delivery has the potential to increase local concentration of drug while decreasing the risk of systemic toxicity. In the present study, a fluorescently labeled bisphosphonate compound (6-FAM-ZOL) was introduced into the human cochlea through the oval window and its distribution within the temporal bone was quantified. Methods In three fresh human temporal bones, we introduced 6-FAM-ZOL via the oval window. We compared these specimens to control specimens treated with artificial perilymph alone. Specimens were then processed, embedded into methyl methacrylate, and ground to the mid-modiolar axis. We quantified the fluorescence in confocal images. Results We found 6-FAM-ZOL to be distributed up to the apical cochlear turn. In specimens treated with 6-FAM-ZOL, we identified a strong baso-apical gradient of fluorescent signal along the lateral cochlear wall and the modiolus both in the scala vestibuli and in the scala tympani. Conclusions Bisphosphonate introduced via the oval window in the human cochlea can be delivered up to the apical cochlear turn. Inter-scalar communication is likely to play an important role in determining patterns of drug delivery in the inner ear. PMID:26859540

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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%.

  19. 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%.

  20. 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

  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. Auditory detection and discrimination in deaf cats: psychophysical and neural thresholds for intracochlear electrical signals.

    PubMed

    Vollmer, M; Beitel, R E; Snyder, R L

    2001-11-01

    More than 30,000 hearing-impaired human subjects have learned to use cochlear implants for speech perception and speech discrimination. To understand the basic mechanisms underlying the successful application of contemporary speech processing strategies, it is important to investigate how complex electrical stimuli delivered to the cochlea are processed and represented in the central auditory system. A deaf animal model has been developed that allows direct comparison of psychophysical thresholds with central auditory neuronal thresholds to temporally modulated intracochlear electrical signals in the same animals. Behavioral detection thresholds were estimated in neonatally deafened cats for unmodulated pulse trains (e.g., 30 pulses/s or pps) and sinusoidal amplitude-modulated (SAM) pulse trains (e.g., 300 pps, SAM at 30 Hz; 300/30 AM). Animals were trained subsequently in a discrimination task to respond to changes in the modulation frequency of successive SAM signals (e.g., 300/8 AM vs. 300/30 AM). During acute physiological experiments, neural thresholds to pulse trains were estimated in the inferior colliculus (IC) and the primary auditory cortex (A1) of the anesthetized animals. Psychophysical detection thresholds for unmodulated and SAM pulse trains were virtually identical. Single IC neuron thresholds for SAM pulse trains showed a small but significant increase in threshold (0.4 dB or 15.5 microA) when compared with thresholds for unmodulated pulse trains. The mean difference between psychophysical and minimum neural thresholds within animals was not significant (mean = 0.3 dB). Importantly, cats also successfully discriminated changes in the modulation frequencies of the SAM signals. Performance on the discrimination task was not affected by carrier rate (100, 300, 500, 1,000, or 1,500 pps). These findings indicate that 1) behavioral and neural response thresholds are based on detection of the peak pulse amplitudes of the modulated and unmodulated signals

  3. Correlation Between Histologic and Radiographic Reconstruction of Intracochlear Electrode Position in Human Temporal Bones

    PubMed Central

    O’Malley, Jennifer T.; Burgess, Barbara J.; Zhu, MengYu; Curtin, Hugh D.; Nadol, Joseph B.

    2014-01-01

    In our laboratory, human temporal bone specimens from patients who in life have undergone cochlear implantation are routinely processed with the implant in situ, embedded in araldite, sectioned at 20 μm and serially photographed during cutting, stained with toluidine blue and mounted on glass slides. From the images, 2D and 3D reconstructions can be made and a very accurate implant insertion depth can be calculated from the 3D reconstructions. However, this method precludes subsequent special stains and further molecular investigations of the tissue including proteomics and immunostaining which is now possible with celloidin embedded tissue. In this study, we correlated measurement of the implant array insertion depth calculated from histologic 3D reconstruction with that measured from 3D radiologic multiplanar reconstruction. Four human temporal bones with cochlear implants underwent post-fixation pre-processing CT imaging with a Siemens Somatom Sensation Scanner. The CT scans from these four bones were downloaded into the Voxar software application, reformatted using the multiplanar reconstruction tool, viewed in three dimensions and measurements of intracochlear insertion lengths of the implants were obtained. The bones were processed routinely for in situ araldite embedding, serial images were made of the block during sectioning, post-processed using PV-Wave® software, aligned with Amira® software, and used to create histologic 3D reconstructions. From these 3D reconstructions, the insertion depth of the electrode array was mathematically calculated. The range of insertion depths was 15.9 mm (case #1) to 26.6 mm (case #4). The two methods, radiographic multiplanar reconstruction and 3D reconstruction, differed by 0.4 – 0.9%. This provides confidence that important localization information about the electrode in situ can be gleaned from CT scans, thereby allowing us to extract the implants prior to processing for celloidin embedment and allow further

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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…

  13. 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

  14. Signal and response properties indicate an optoacoustic effect underlying the intra-cochlear laser-optical stimulation

    NASA Astrophysics Data System (ADS)

    Kallweit, Nicole; Baumhoff, Peter; Krueger, Alexander; Tinne, Nadine; Heisterkamp, Alexander; Kral, Andrej; Maier, Hannes; Ripken, Tammo

    2016-02-01

    Optical cochlea stimulation is under investigation as a potential alternative to conventional electric cochlea implants in treatment of sensorineural hearing loss. If direct optical stimulation of spiral ganglion neurons (SGNs) would be feasible, a smaller stimulation volume and, therefore, an improved frequency resolution could be achieved. However, it is unclear whether the mechanism of optical stimulation is based on direct neuronal stimulation or on optoacoustics. Animal studies on hearing vs. deafened guinea pigs already identified the optoacoustic effect as potential mechanism for intra-cochlear optical stimulation. In order to characterize the optoacoustic stimulus more thoroughly the acoustic signal along the beam path of a pulsed laser in water was quantified and compared to the neuronal response properties of hearing guinea pigs stimulated with the same laser parameters. Two pulsed laser systems were used for analyzing the influence of variable pulse duration, pulse energy, pulse peak power and absorption coefficient. Preliminary results of the experiments in water and in vivo suggesta similar dependency of response signals on the applied laser parameters: Both datasets show an onset and offset signal at the beginning and the end of the laser pulse. Further, the resulting signal amplitude depends on the pulse peak power as well as the temporal development of the applied laser pulse. The data indicates the maximum of the first derivative of power as the decisive factor. In conclusion our findings strengthen the hypothesis of optoacoustics as the underlying mechanism for optical stimulation of the cochlea.

  15. Possibility of differentiation of cochlear electrodes in radiological measurements of the intracochlear and chorda-facial angle position.

    PubMed

    Diogo, I; Walliczeck, U; Taube, J; Franke, N; Teymoortash, A; Werner, J; Güldner, C

    2016-08-01

    Due to an increasing number of cochlear implantations, quality control has become more important. In addition to intraoperative biophysical measurements, radiological imaging is another possibility. An upcoming technique regarding this is Cone Beam CT (CBCT). Sixty-five data sets (35 Nucleus Contour Advance-Cochlear; 30 Flex Soft-MedEl) of postoperative imaging by CBCT (Accu-I-tomo F17, Morita, Kyoto, Japan) underwent further evaluation. Insertion angle, height of the cochlea, distance of the electrode to the medial or lateral wall, angle between chorda tympani and facial nerve and the precise position of the electrode cable in the facial-chordal angle were determined. The typical difference between the perimodiolar and lateral course of the electrodes could also be shown in radiological measurements. This demonstrates the accuracy and advantage of CBCT in visualisation of small structures with fewer metal artifacts. Furthermore, in 75% of patients, the angle of the chorda and facial nerve could be visualised. Significant differences in dependence of the electrode type for the relation of them to the facial nerve could be seen. In conclusion, CBCT achieves reliable visualisation and detailed imaging-based measurements of the intracochlear position of different cochlea electrodes. Additionally, clinically known differences can be reproduced. Even visualisation of the position of the electrode in the chorda-facial angle is possible. Therefore, CBCT is a useful tool in intra- and postoperative control of cochlear implants.

  16. 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.

  17. 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.

  18. 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 ...

  19. Correlation between word recognition score and intracochlear new bone and fibrous tissue after cochlear implantation in the human.

    PubMed

    Kamakura, Takefumi; Nadol, Joseph B

    2016-09-01

    Cochlear implantation is an effective, established procedure for patients with profound deafness. Although implant electrodes have been considered as biocompatible prostheses, surgical insertion of the electrode induces various changes within the cochlea. Immediate changes include insertional trauma to the cochlea. Delayed changes include a tissue response consisting of inflammation, fibrosis and neo-osteogenesis induced by trauma and an immunologic reaction to a foreign body. The goal of this study was to evaluate the effect of these delayed changes on the word recognition scores achieved post-operatively. Seventeen temporal bones from patients who in life had undergone cochlear implantation were prepared for light microscopy. We digitally calculated the volume of fibrous tissue and new bone within the cochlea using Amira(®) three-dimensional reconstruction software and assessed the correlations of various clinical and histologic factors. The postoperative CNC word score was positively correlated with total spiral ganglion cell count. Fibrous tissue and new bone were found within the cochlea of all seventeen specimens. The postoperative CNC word score was negatively correlated with the % volume of new bone within the scala tympani, scala media/vestibuli and the cochlea, but not with the % volume of fibrous tissue. The % volume of new bone in the scala media/vestibuli was positively correlated with the degree of intracochlear insertional trauma, especially trauma to the basilar membrane. Our results revealed that the % volume of new bone as well as residual total spiral ganglion cell count are important factors influencing post-implant hearing performance. New bone formation may be reduced by limiting insertional trauma and increasing the biocompatibility of the electrodes.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  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. 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.

  7. Breath sounds

    MedlinePlus

    ... are believed to occur when air opens closed air spaces. Rales can be further described as moist, dry, fine, and coarse. Rhonchi. Sounds that resemble snoring. They occur when air is blocked or air flow becomes rough through ...

  8. 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)

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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…

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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…

  12. 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…

  13. 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.

  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. 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

  16. 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.

  17. 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.

  18. 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 ...

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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…

  12. 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.

  13. 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)

  14. 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…

  15. 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.

  16. 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…

  17. 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…

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Spatial Statistics of Deep-Water Ambient Noise; Dispersion Relations for Sound Waves and Shear Waves

    DTIC Science & Technology

    2015-09-30

    Environmental and system data will also be depth-profiled, including temperature , salinity, pressure and (directly measured) sound speed, along...configurations, and an environmental sensor package [Conductivity- Temperature - Depth sensor (CTD) plus sound speed sensor (SVX)]. The system is untethered...Dispersion Relations for Sound Waves and Shear Waves Michael J. Buckingham Marine Physical Laboratory, Scripps Institution of Oceanography University

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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)

  11. 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)

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  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. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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…

  7. 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)

  8. 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…

  9. 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,…

  10. 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.

  11. 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.

  12. 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.

  13. 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].

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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'…

  20. 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…

  1. 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…

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. Cochlear Implant Electrode Effect on Sound Energy Transfer within the Cochlea during Acoustic Stimulation

    PubMed Central

    Greene, Nathaniel T.; Mattingly, Jameson K.; Jenkins, Herman A.; Tollin, Daniel J.; Easter, James R.; Cass, Stephen P.

    2015-01-01

    Hypothesis Cochlear implants (CI) designed for hearing preservation will not alter mechanical properties of the middle and inner ear as measured by intracochlear pressure (PIC) and stapes velocity (Vstap). Background CIs designed to provide combined electrical and acoustic stimulation (EAS) are now available. To maintain functional acoustic hearing, it is important to know if a CI electrode can alter middle or inner ear mechanics, as any alteration could contribute to elevated low-frequency thresholds in EAS patients. Methods Seven human cadaveric temporal bones were prepared, and pure-tone stimuli from 120Hz–10kHz were presented at a range of intensities up to 110 dB SPL. PIC in the scala vestibuli (PSV) and tympani (PST) were measured with fiber-optic pressure sensors concurrently with VStap using laser Doppler vibrometry. Five CI electrodes from two different manufacturers, with varying dimensions were inserted via a round window approach at six different depths (16–25 mm). Results The responses of PIC and VStap to acoustic stimulation were assessed as a function of stimulus frequency, normalized to SPL in the external auditory canal (EAC), in baseline and electrode inserted conditions. Responses measured with electrodes inserted were generally within ~5 dB of baseline, indicating little effect of cochlear implant electrode insertion on PIC and VStap. Overall, mean differences across conditions were small for all responses, and no substantial differences were consistently visible across electrode types. Conclusions Results suggest that the influence of a CI electrode on middle and inner ear mechanics is minimal, despite variation in electrode lengths and configurations. PMID:26333018

  16. 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.

  17. Prediction of the characteristics of two types of pressure waves in the cochlea: Theoretical considerations

    NASA Astrophysics Data System (ADS)

    Andoh, Masayoshi; Wada, Hiroshi

    2004-07-01

    The aim of this study was to predict the characteristics of two types of cochlear pressure waves, so-called fast and slow waves. A two-dimensional finite-element model of the organ of Corti (OC), including fluid-structure interaction with the surrounding lymph fluid, was constructed. The geometry of the OC at the basal turn was determined from morphological measurements of others in the gerbil hemicochlea. As far as mechanical properties of the materials within the OC are concerned, previously determined mechanical properties of portions within the OC were adopted, and unknown mechanical features were determined from the published measurements of static stiffness. Time advance of the fluid-structure scheme was achieved by a staggered approach. Using the model, the magnitude and phase of the fast and slow waves were predicted so as to fit the numerically obtained pressure distribution in the scala tympani with what is known about intracochlear pressure measurement. When the predicted pressure waves were applied to the model, the numerical result of the velocity of the basilar membrane showed good agreement with the experimentally obtained velocity of the basilar membrane documented by others. Thus, the predicted pressure waves appeared to be reliable. Moreover, it was found that the fluid-structure interaction considerably influences the dynamic behavior of the OC at frequencies near the characteristic frequency.

  18. 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.

  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. 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.

  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 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

  4. 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.

  5. 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.

  6. 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

  7. 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

    2017-02-08

    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.

  8. 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.

  9. [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.

  10. 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.

  11. 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..

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. Auditory Perception of Complex Sounds.

    DTIC Science & Technology

    1987-10-30

    processes that underlie several aspects of complex pattern recog- nition -- whether of speech, of music , or of environmental sounds. These patterns differ...quality or timbre can play similar grouping roles in auditory steams. Most of the experimental work has concerned timing of successive sounds in sequences...auditory perceptual processes that underlie several aspects of complex pattern recognition - whether of speech, of music , or of environmental sounds

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Nonlinear behavior of the tarka flute's distinctive sounds.

    PubMed

    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.

  8. 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.

  9. Advanced Systems for Monitoring Underwater Sounds

    NASA Technical Reports Server (NTRS)

    Lane, Michael; Van Meter, Steven; Gilmore, Richard Grant; Sommer, Keith

    2007-01-01

    data acquired by instrumentation systems other than PAMS. A PAMS is packaged as a battery-powered unit, mated with external sensors, that can operate in the ocean at any depth from 2 m to 1 km. A PAMS includes a pressure housing, a deep-sea battery, a hydrophone (which is one of the mating external sensors), and an external monitor and keyboard box. In addition to acoustic transducers, external sensors can include temperature probes and, potentially, underwater cameras. The pressure housing contains a computer that includes a hard drive, DC-to- DC power converters, a post-amplifier board, a sound card, and a universal serial bus (USB) 4-port hub.

  10. Insect sound production: transduction mechanisms and impedance matching.

    PubMed

    Bennet-Clark, H C

    1995-01-01

    The chain of sound production in insects can be summarised as: (1) muscle power-->(2) mechanical vibration of the sound-producing structure-->(3) acoustic loading of this source-->(4) sound radiation. At each link (-->) optimal impedance matching is desirable but, to meet other acoustic requirements, each stage has special properties. The properties of sound waves are discussed in the context of impedance matching between sources of different sizes or configurations and the surrounding fluid medium. Muscles produce high pressures over small areas, but sound sources produce low pressures over large areas. Link 1-->2 requires a change in the force: area ratio between the muscle and the sound source. Because the source size is necessarily small, sounds tend to be produced at a higher frequency than that of the driving muscle contraction, so link 1-->2 may involve a frequency multiplication mechanism. This can also be regarded as a mechanism of impedance matching between the aqueous muscle and the structure from which the insect produces sound. Stage 2 typically involves a resonant structure that determines the song frequency and is excited by link 1-->2. If link 2-->3 provides good impedance matching, the mechanical resonance is likely to be damped, with loss of song purity. So it is desirable for the stage 2 resonance to be sustained by coherent excitation and for the acoustic loading (link 2-->3) to maintain the dominant frequency between stages 2 and 4. Examples where this occurs are cricket wings and cicadas. At stage 3, the source size or configuration should allow impedance matching between the sound source (3) and its load (4). A variety of acoustic devices are exploited, leading to loud, efficient sound production. Examples that use resonant loads, tuned to the insects' song frequency, are the burrows of mole crickets and the abdomens of cicadas. Overall, the mechanisms of sound production of many insects are capable of producing songs of high species

  11. Deep-sea soundings

    NASA Astrophysics Data System (ADS)

    Brooks, David A.

    Bathymetric charts for many areas of the ocean are cheap and accurate, and we usually take their availability for granted. In these times of abundant information, it is easy to forget the wonder and excitement of the last century, when mechanical sounding machines revealed for the first time the major features of the ocean depths. Who would not be awed by the graceful sweep of the Blake Plateau or the plunging depths of the Puerto Rico Trench, and who could remain unimpressed by undersea mountain ranges more majestic than any in view? In his 1888 book, entitled Three Cruises of the Blake, Alexander Agassiz has this to say about the spectacular Caribbean bottom topography: “Compared to such panoramas the finest views of the range of the Alps sink into insignificance; it is only when we get a view of portions of the Andes from the sea-coast…that we get anything approximating to it in grandeur.”

  12. The Sounds of Earth

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Flying board Voyagers 1 and 2 are identical 'golden' records, carrying the story of Earth far into deep space. The 12 inch gold-plated copper discs contain greetings in 60 languages, samples of music from different cultures and eras, and natural and man-made sounds from Earth. They also contain electronic information that an advanced technological civilization could convert into diagrams and photographs. The cover of each gold plated aluminum jacket, designed to protect the record from micrometeorite bombardment, also serves a double purpose in providing the finder a key to playing the record. The explanatory diagram appears on both the inner and outer surfaces of the cover, as the outer diagram will be eroded in time. Currently, both Voyager probes are sailing adrift in the black sea of interplanetary space, having left our solar system years ago.

  13. Sounds Clear Enough

    NASA Technical Reports Server (NTRS)

    Zak, Alan

    2004-01-01

    I'm a vice president at Line6, where we produce electronics for musical instruments. My company recently developed a guitar that can be programmed to sound like twenty-five different classic guitars - everything from a 1928 National 'Tricone' to a 1970 Martin. It is quite an amazing piece of technology. The guitar started as a research project because we needed to know if the technology was going to be viable and if the guitar design was going to be practical. I've been in this business for about twenty years now, and I still enjoy starting up projects whenever the opportunity presents itself. During the research phase, I headed up the project myself. Once we completed our preliminary research and made the decision to move into development, that's when I handed the project off - and that's where this story really begins.

  14. Sounding out science

    SciTech Connect

    Holloway, M.

    1996-10-01

    The Exxon Valdez catastrophe, which soiled Alaska`s Prince William Sound in 1989, was the most studied oil spill in history. But because of how they framed their inquiries, investigators have learned less than they could about how nature heals itself. The studies of Exxon and the state of Alaska - including the departments of Fish and Game and of Environmental Conservation - conducted to prove their respective points, were kept largely secret untill legal settlements were reached. This secrecy reduced most of the pillars of science to rubble: out went scientific dialog, data sharing, and for some parties, peer view. Millions of dollars were shelled out in duplicate studies that reached opposite conclusions. Beyond the quality of science lies the public interpretation of science. Even though NOAA has shown that cleaning up can do more harm than good, demands to clean up persist. 7 figs.

  15. The monster sound pipe

    NASA Astrophysics Data System (ADS)

    Ruiz, Michael J.; Perkins, James

    2017-03-01

    Producing a deep bass tone by striking a large 3 m (10 ft) flexible corrugated drainage pipe immediately grabs student attention. The fundamental pitch of the corrugated tube is found to be a semitone lower than a non-corrugated smooth pipe of the same length. A video (https://youtu.be/FU7a9d7N60Y) of the demonstration is included, which illustrates how an Internet keyboard can be used to estimate the fundamental pitches of each pipe. Since both pipes have similar end corrections, the pitch discrepancy between the smooth pipe and drainage tube is due to the corrugations, which lower the speed of sound inside the flexible tube, dropping its pitch a semitone.

  16. Acoustical and perceptual assessment of water sounds and their use over road traffic noise.

    PubMed

    Galbrun, Laurent; Ali, Tahrir T

    2013-01-01

    This paper examines physical and perceptual properties of water sounds generated by small to medium sized water features that have applications for road traffic noise masking. A large variety of water sounds were produced in the laboratory by varying design parameters. Analysis showed that estimations can be made on how these parameters affect sound pressure levels, frequency content, and psychoacoustic properties. Comparisons with road traffic noise showed that there is a mismatch between the frequency responses of traffic noise and water sounds, with the exception of waterfalls with high flow rates, which can generate large low frequency levels comparable to traffic noise. Perceptual assessments were carried out in the context of peacefulness and relaxation, where both water sounds and noise from dense road traffic were audible. Results showed that water sounds should be similar or not less than 3 dB below the road traffic noise level (confirming previous research), and that stream sounds tend to be preferred to fountain sounds, which are in turn preferred to waterfall sounds. Analysis made on groups of sounds also indicated that low sharpness and large temporal variations were preferred on average, although no acoustical or psychoacoustical parameter correlated well with the individual sound preferences.

  17. Hearing thresholds of two harbor seals (Phoca vitulina) for playbacks of multiple pile driving strike sounds.

    PubMed

    Kastelein, Ronald A; Hoek, Lean; Gransier, Robin; Jennings, Nancy

    2013-09-01

    Pile driving, which creates high amplitude sounds with potentially negative impacts on the marine environment, is used to attach wind turbines to the sea bed. To quantify the distance at which pile driving sounds can be detected by harbor seals, unmasked hearing thresholds were obtained for series of five pile driving sounds recorded at 100 and 800 m from a pile driving location. The played back spectra resembled the spectra of sounds recorded under certain conditions 10-50 km from an offshore pile driving site. The lower the received level, the later within the series of sounds the harbor seals responded. The mean 50% detection threshold sound exposure levels for any sound in the series were: 40 (seal 01, 100 m), 39 (seal 01, 800 m), 43 (seal 02, 100 m), and 43 (seal 02, 800 m) dB re 1 μPa(2)s (add 9 dB for sound pressure level, dB re 1 μPa). The mean 50% detection thresholds based on detection of only the first sound of the series were ca. 5 dB higher. Detection at sea depends on the actual propagation conditions and on the degree of masking of the sounds by ambient noise, but the present study suggests that pile driving sounds are audible to harbor seals up to hundreds of kilometers from pile driving sites.

  18. Static behavior of a graphene-based sound-emitting device.

    PubMed

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

    2012-06-07

    Due to the extremely high thermal conductivity and low heat capacity per unit area of graphene, it is possible to fabricate an efficient sound-emitting device based on the thermoacoustic effect with no mechanical vibration. In this paper, the fundamental performance of this new graphene sound-emitting device (G-SED) is investigated in terms of its static behavior. The sound amplitude mapping shows that the G-SED has good sound performance under 0.01 W. The sound frequency spectra measured at different distances and angles show that the G-SED has good sound directivity. It is possible to realize sound wave manipulation by using an array of G-SEDs. The relationship between the temperature of graphene and the sound frequency was investigated by a thermal imaging instrument. The fast transient sound response in real time was recorded by applying 60 μs short time multi-pulses and single-pulse. The stable sound emission at a constant sound pressure amplitude with low noise was observed for continuous operation under a fixed frequency over several hours. Such significant performances in this G-SED indicate broad applications, and shed light on the use of graphene in the field of acoustics.

  19. Applications of Sound Spectrum Analysis

    ERIC Educational Resources Information Center

    Moran, Timothy

    2007-01-01

    The physics of sound is often studied in introductory physics class experiments involving a tube of resonating air. In typical setups, pistons control the length of a cylindrical space or a microphone is moved within a tube. While these activities are useful and can be made very quantitative, they don't directly demonstrate the sounds that are…

  20. Letter Recognition and Sound Identification.

    ERIC Educational Resources Information Center

    Prior, Jennifer

    This lesson, which is most appropriate for kindergartners, reviews letter names and their sounds through a group letter recognition activity, a picture book activity, and alphabet practice with several online activities. During three 30-minute sessions, students will: identify the letters of the alphabet; identify the sounds of letters; identify…

  1. Designing a Sound Reducing Wall

    ERIC Educational Resources Information Center

    Erk, Kendra; Lumkes, John; Shambach, Jill; Braile, Larry; Brickler, Anne; Matthys, Anna

    2015-01-01

    Acoustical engineers use their knowledge of sound to design quiet environments (e.g., classrooms and libraries) as well as to design environments that are supposed to be loud (e.g., concert halls and football stadiums). They also design sound barriers, such as the walls along busy roadways that decrease the traffic noise heard by people in…

  2. Dynamic Pressure Microphones

    NASA Astrophysics Data System (ADS)

    Werner, E.

    In 1876, Alexander Graham Bell described his first telephone with a microphone using magnetic induction to convert the voice input into an electric output signal. The basic principle led to a variety of designs optimized for different needs, from hearing impaired users to singers or broadcast announcers. From the various sound pressure versions, only the moving coil design is still in mass production for speech and music application.

  3. Airborne sound propagation over sea during offshore wind farm piling.

    PubMed

    Van Renterghem, T; Botteldooren, D; Dekoninck, L

    2014-02-01

    Offshore piling for wind farm construction has attracted a lot of attention in recent years due to the extremely high noise emission levels associated with such operations. While underwater noise levels were shown to be harmful for the marine biology, the propagation of airborne piling noise over sea has not been studied in detail before. In this study, detailed numerical calculations have been performed with the Green's Function Parabolic Equation (GFPE) method to estimate noise levels up to a distance of 10 km. Measured noise emission levels during piling of pinpiles for a jacket-foundation wind turbine were assessed and used together with combinations of the sea surface state and idealized vertical sound speed profiles (downwind sound propagation). Effective impedances were found and used to represent non-flat sea surfaces at low-wind sea states 2, 3, and 4. Calculations show that scattering by a rough sea surface, which decreases sound pressure levels, exceeds refractive effects, which increase sound pressure levels under downwind conditions. This suggests that the presence of wind, even when blowing downwind to potential receivers, is beneficial to increase the attenuation of piling sound over the sea. A fully flat sea surface therefore represents a worst-case scenario.

  4. Perfect sound insulation property of reclaimed waste tire rubber

    NASA Astrophysics Data System (ADS)

    Ubaidillah, Harjana, Yahya, Iwan; Kristiani, Restu; Muqowi, Eki; Mazlan, Saiful Amri

    2016-03-01

    This article reports an experimental investigation of sound insulation and absorption performance of a materials made of reclaimed ground tire rubber which is known as un-recyclable thermoset. The bulk waste tire is processed using single step recycling methods namely high-pressure high-temperature sintering (HPHTS). The bulk waste tire is simply placed into a mold and then a pressure load of 3 tons and a heating temperature of 200°C are applied to the mold. The HPHTS conducted for an hour and then it is cooled in room temperature. The resulted product is then evaluated the acoustical properties namely sound transmission loss (STL) and sound absorption coefficient using B&K Tube Kit Type 4206-T based on ISO 10534-2, ASTM E1050 and ASTM E2611. The sound absorption coefficient is found about 0.04 until 0.08 while STL value ranges between 50 to 60 dB. The sound absorption values are found to be very low (<0.1), while the average STL is higher than other elastomeric matrix found in previous work. The reclaimed tire rubber through HPHTS technique gives good soundproof characteristic.

  5. 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.

  6. Heart sound and lung sound separation algorithms: a review.

    PubMed

    Nersisson, Ruban; Noel, Mathew M

    2017-01-01

    Breath and cardiac sounds are two major bio sound signals. In this, heart sounds are produced by movement of some body parts such as heart valve, leaflets and the blood flow through the vessels, whereas lung sounds generates due to the air in and out flow through airways during breathing cycle. These two signals are recorded from chest region. These two signals have very high clinical importance for the patient who is critically ill. The lung functions and the cardiac cycles are continuously monitored for such patients with the help of the bio sound signal captured using suitable sensing mechanism or with auscultation techniques. But these two signals mostly superimpose with each other, so the separation of these heart sound signals (HSS) and the lung sound signals (LSS) is of great research interest. There are so many different techniques proposed for this purpose. In this paper, a study is carried out on different algorithms used for the separation of HSS from LSS, and also the results of major four separation algorithms are compared.

  7. A new concept in underwater high fidelity low frequency sound generation

    NASA Astrophysics Data System (ADS)

    Fonseca, Paulo J.; Alves, J. Maia

    2012-05-01

    This article reports on a new type of system for high fidelity underwater sound generation (patent pending PT105474). The system includes an underwater sound actuator and the corresponding electronic driver. The sound is generated by a rigid plate that is actuated (both for positioning/dumping and excitation) using purely electromagnetic forces, thus, avoiding the use of any elastic membrane. Since there is no compressible air inside the device, which is flooded by water, the operation of this device is independent from depth, broadening its applications to any water pressure. Characterization of the frequency response, the radiation characteristics, and the dynamic range of this new device for underwater sound generation is presented.

  8. A new concept in underwater high fidelity low frequency sound generation.

    PubMed

    Fonseca, Paulo J; Alves, J Maia

    2012-05-01

    This article reports on a new type of system for high fidelity underwater sound generation (patent pending PT105474). The system includes an underwater sound actuator and the corresponding electronic driver. The sound is generated by a rigid plate that is actuated (both for positioning/dumping and excitation) using purely electromagnetic forces, thus, avoiding the use of any elastic membrane. Since there is no compressible air inside the device, which is flooded by water, the operation of this device is independent from depth, broadening its applications to any water pressure. Characterization of the frequency response, the radiation characteristics, and the dynamic range of this new device for underwater sound generation is presented.

  9. Nonlinear interactions in superfluid dynamics: Nonstationary heat transfer due to second sound shock waves

    NASA Technical Reports Server (NTRS)

    Liepmann, H. W.; Torczynski, J. R.

    1983-01-01

    Second sound techniques were used to study superfluid helium. Second sound shock waves produced relative velocities in the bulk fluid. Maximum counterflow velocities produced in this way are found to follow the Langer-Fischer prediction for the fundamental critical velocity in its functional dependence on temperature and pressure. Comparison of successive shock and rotating experiments provides strong evidence that breakdown results in vorticity production in the flow behind the shock. Schlieren pictures have verified the planar nature of second sound shocks even after multiple reflections. The nonlinear theory of second sound was repeatedly verified in its prediction of double shocks and other nonlinear phenomena.

  10. Relations among pure-tone sound stimuli, neural activity, and the loudness sensation

    NASA Technical Reports Server (NTRS)

    Howes, W. L.

    1972-01-01

    Both the physiological and psychological responses to pure-tone sound stimuli are used to derive formulas which: (1) relate the loudness, loudness level, and sound-pressure level of pure tones; (2) apply continuously over most of the acoustic regime, including the loudness threshold; and (3) contain no undetermined coefficients. Some of the formulas are fundamental for calculating the loudness of any sound. Power-law formulas relating the pure-tone sound stimulus, neural activity, and loudness are derived from published data.

  11. MEMS directional acoustic sensor for locating sound sources

    NASA Astrophysics Data System (ADS)

    Karunasiri, Gamani; Alves, Fabio; Swan, William

    2016-02-01

    The conventional directional sound sensing systems employ an array of spatially separated microphones to achieve directional sensing. However, there are insects such as Ormia ochracea fly that can determine the direction of sound using a miniature hearing organ much smaller than the wavelength of sound it detects. The MEMS based sensors mimicking the fly's hearing system was fabricated using SOI substrate with 25 micrometer device layer. The sensor was designed to operate around 1.7 kHz, consists of two 1.2 mm × 1.2 mm wings connected in the middle by a 3 mm × 30 micrometer bridge. The entire structure is connected to the substrate by two torsional legs at the center. The sensor operates at its bending resonance frequency and has cosine directional characteristics similar to that of a pressure gradient microphone. For unambiguously determining the direction of sound, two sensors were assembled with a canted angle and outputs of the two sensors were processed to uniquely locate the bearing. At the bending resonant frequency (1.7 kHz) an output voltage of about 25 V/Pa was measured. The uncertainty of the bearing of sound ranged from less than 0.3 degrees close to the normal axis (0 degree) to 3 degrees at the limits of coverage (+/- 60 degrees) based on the 30 degree canted angle used. These findings indicate the potential use of a dual MEMS direction finding sensor assembly to locate sound sources with high accuracy.

  12. The isolation of low frequency impact sounds in hotel construction

    NASA Astrophysics Data System (ADS)

    LoVerde, John J.; Dong, David W.

    2002-11-01

    One of the design challenges in the acoustical design of hotels is reducing low frequency sounds from footfalls occurring on both carpeted and hard-surfaced floors. Research on low frequency impact noise [W. Blazier and R. DuPree, J. Acoust. Soc. Am. 96, 1521-1532 (1994)] resulted in a conclusion that in wood construction low frequency impact sounds were clearly audible and that feasible control methods were not available. The results of numerous FIIC (Field Impact Insulation Class) measurements performed in accordance with ASTM E1007 indicate the lack of correlation between FIIC ratings and the reaction of occupants in the room below. The measurements presented include FIIC ratings and sound pressure level measurements below the ASTM E1007 low frequency limit of 100 Hertz, and reveal that excessive sound levels in the frequency range of 63 to 100 Hertz correlate with occupant complaints. Based upon this history, a tentative criterion for maximum impact sound level in the low frequency range is presented. The results presented of modifying existing constructions to reduce the transmission of impact sounds at low frequencies indicate that there may be practical solutions to this longstanding problem.

  13. On the sound radiation of a rolling tyre

    NASA Astrophysics Data System (ADS)

    Kropp, Wolfgang; Sabiniarz, Patrick; Brick, Haike; Beckenbauer, Thomas

    2012-04-01

    The sound radiation from rolling tyres is still not very well understood. Although details such as horn effect or directivity during rolling have been investigated, it is not clear which vibrational modes of the tyre structure are responsible for the radiated sound power. In this work an advanced tyre model based on Wave Guide Finite Elements is used in connection with a contact model validated in previous work. With these tools the tyre vibrations during rolling on an ISO surface are simulated. Starting from the calculated contact forces in time the amplitudes of the modes excited during rolling are determined as function of frequency. A boundary element model also validated in previous work is applied to predict the sound pressure level on a reference surface around a tyre placed on rigid ground as function of the modal composition of the tyre vibrations. Taking into account different modes when calculating the vibrational field as input into the boundary element calculations, it is possible to identify individual modes or groups of modes of special relevance for the radiated sound power. The results show that mainly low-order modes with relative low amplitudes but high radiation efficiency in the frequency range around 1 kHz are responsible for the radiated sound power at these frequencies, while those modes which are most strongly excited in that frequency range during rolling are irrelevant for the radiated sound power. This fact is very essential when focusing on the design of quieter tyres.

  14. Sound attenuation apparatus

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P. (Inventor); Grosveld, Ferdinand M. W. A. (Inventor)

    1991-01-01

    An apparatus is disclosed for reducing acoustic transmission from mechanical or acoustic sources by means of a double wall partition, within which an acoustic pressure field is generated by at least one secondary acoustic source. The secondary acoustic source is advantageously placed within the partition, around its edges, or it may be an integral part of a wall of the partition.

  15. Meteorological Sounding Systems

    DTIC Science & Technology

    1969-12-15

    are then reduced to meaningful data by the ground operator. More sophisticated systems include use of rockets to carry a radio- sonde to a specific...Voltmeter e. Spectrum analyzer f. Signal generator g. Temperature, humidity, and pressure chamber h. Theodolite or surveyors transit i. Dummy load j

  16. Acoustic transistor: Amplification and switch of sound by sound

    NASA Astrophysics Data System (ADS)

    Liang, Bin; Kan, Wei-wei; Zou, Xin-ye; Yin, Lei-lei; Cheng, Jian-chun

    2014-08-01

    We designed an acoustic transistor to manipulate sound in a manner similar to the manipulation of electric current by its electrical counterpart. The acoustic transistor is a three-terminal device with the essential ability to use a small monochromatic acoustic signal to control a much larger output signal within a broad frequency range. The output and controlling signals have the same frequency, suggesting the possibility of cascading the structure to amplify an acoustic signal. Capable of amplifying and switching sound by sound, acoustic transistors have various potential applications and may open the way to the design of conceptual devices such as acoustic logic gates.

  17. Speech Sound Disorders: Articulation and Phonological Processes

    MedlinePlus

    ... Speech, Language and Swallowing / Disorders and Diseases Speech Sound Disorders: Articulation and Phonological Processes What are speech ... individuals with speech sound disorders ? What are speech sound disorders? Most children make some mistakes as they ...

  18. The influence of crowd density on the sound environment of commercial pedestrian streets.

    PubMed

    Meng, Qi; Kang, Jian

    2015-04-01

    Commercial pedestrian streets are very common in China and Europe, with many situated in historic or cultural centres. The environments of these streets are important, including their sound environments. The objective of this study is to explore the relationships between the crowd density and the sound environments of commercial pedestrian streets. On-site measurements were performed at the case study site in Harbin, China, and a questionnaire was administered. The sound pressure measurements showed that the crowd density has an insignificant effect on sound pressure below 0.05 persons/m2, whereas when the crowd density is greater than 0.05 persons/m2, the sound pressure increases with crowd density. The sound sources were analysed, showing that several typical sound sources, such as traffic noise, can be masked by the sounds resulting from dense crowds. The acoustic analysis showed that crowd densities outside the range of 0.10 to 0.25 persons/m2 exhibited lower acoustic comfort evaluation scores. In terms of audiovisual characteristics, the subjective loudness increases with greater crowd density, while the acoustic comfort decreases. The results for an indoor underground shopping street are also presented for comparison.

  19. Pitch features of environmental sounds

    NASA Astrophysics Data System (ADS)

    Yang, Ming; Kang, Jian

    2016-07-01

    A number of soundscape studies have suggested the need for suitable parameters for soundscape measurement, in addition to the conventional acoustic parameters. This paper explores the applicability of pitch features that are often used in music analysis and their algorithms to environmental sounds. Based on the existing alternative pitch algorithms for simulating the perception of the auditory system and simplified algorithms for practical applications in the areas of music and speech, the applicable algorithms have been determined, considering common types of sound in everyday soundscapes. Considering a number of pitch parameters, including pitch value, pitch strength, and percentage of audible pitches over time, different pitch characteristics of various environmental sounds have been shown. Among the four sound categories, i.e. water, wind, birdsongs, and urban sounds, generally speaking, both water and wind sounds have low pitch values and pitch strengths; birdsongs have high pitch values and pitch strengths; and urban sounds have low pitch values and a relatively wide range of pitch strengths.

  20. Time frequency analysis of sound from a maneuvering rotorcraft

    NASA Astrophysics Data System (ADS)

    Stephenson, James H.; Tinney, Charles E.; Greenwood, Eric; Watts, Michael E.

    2014-10-01

    The acoustic signatures produced by a full-scale, Bell 430 helicopter during steady-level-flight and transient roll-right maneuvers are analyzed by way of time-frequency analysis. The roll-right maneuvers comprise both a medium and a fast roll rate. Data are acquired using a single ground based microphone that are analyzed by way of the Morlet wavelet transform to extract the spectral properties and sound pressure levels as functions of time. The findings show that during maneuvering operations of the helicopter, both the overall sound pressure level and the blade-vortex interaction sound pressure level are greatest when the roll rate of the vehicle is at its maximum. The reduced inflow in the region of the rotor disk where blade-vortex interaction noise originates is determined to be the cause of the increase in noise. A local decrease in inflow reduces the miss distance of the tip vortex and thereby increases the BVI noise signature. Blade loading and advance ratios are also investigated as possible mechanisms for increased sound production, but are shown to be fairly constant throughout the maneuvers.

  1. 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%).

  2. Experimental study of the speed of sound in liquid and gaseous refrigerant R-407C

    NASA Astrophysics Data System (ADS)

    Komarov, S. G.; Stankus, S. V.

    2016-01-01

    The speed of sound in liquid and gaseous refrigerant R-407C was measured by the method of ultrasonic interferometer in the temperature range from 293 to 373 K and pressure from 0.05 to 0.5 to 3.7 MPa. The experimental uncertainties of the temperature, pressure, and speed of sound measurements were estimated to be within ±20 mK, ±4 kPa, and ±(0.1-0.3) %, respectively. The obtained results are compared with the calculated speed of sound from the fundamental state equation for the Helmholtz free energy.

  3. Air-borne sound generated by sea waves.

    PubMed

    Bolin, Karl; Åbom, Mats

    2010-05-01

    This paper describes a semi-empiric model and measurements of air-borne sound generated by breaking sea waves. Measurements have been performed at the Baltic Sea. Shores with different slopes and sediment types have been investigated. Results showed that the sound pressure level increased from 60 dB at 0.4 m wave height to 78 dB at 2.0 m wave height. The 1/3 octave spectrum was dependent on the surf type. A scaling model based on the dissipated wave power and a surf similarity parameter is proposed and compared to measurements. The predictions show satisfactory agreement to the measurements.

  4. EUVS Sounding Rocket Payload

    NASA Technical Reports Server (NTRS)

    Stern, Alan S.

    1996-01-01

    During the first half of this year (CY 1996), the EUVS project began preparations of the EUVS payload for the upcoming NASA sounding rocket flight 36.148CL, slated for launch on July 26, 1996 to observe and record a high-resolution (approx. 2 A FWHM) EUV spectrum of the planet Venus. These preparations were designed to improve the spectral resolution and sensitivity performance of the EUVS payload as well as prepare the payload for this upcoming mission. The following is a list of the EUVS project activities that have taken place since the beginning of this CY: (1) Applied a fresh, new SiC optical coating to our existing 2400 groove/mm grating to boost its reflectivity; (2) modified the Ranicon science detector to boost its detective quantum efficiency with the addition of a repeller grid; (3) constructed a new entrance slit plane to achieve 2 A FWHM spectral resolution; (4) prepared and held the Payload Initiation Conference (PIC) with the assigned NASA support team from Wallops Island for the upcoming 36.148CL flight (PIC held on March 8, 1996; see Attachment A); (5) began wavelength calibration activities of EUVS in the laboratory; (6) made arrangements for travel to WSMR to begin integration activities in preparation for the July 1996 launch; (7) paper detailing our previous EUVS Venus mission (NASA flight 36.117CL) published in Icarus (see Attachment B); and (8) continued data analysis of the previous EUVS mission 36.137CL (Spica occultation flight).

  5. Sound symbolism: the role of word sound in meaning.

    PubMed

    Svantesson, Jan-Olof

    2017-03-22

    The question whether there is a natural connection between sound and meaning or if they are related only by convention has been debated since antiquity. In linguistics, it is usually taken for granted that 'the linguistic sign is arbitrary,' and exceptions like onomatopoeia have been regarded as marginal phenomena. However, it is becoming more and more clear that motivated relations between sound and meaning are more common and important than has been thought. There is now a large and rapidly growing literature on subjects as ideophones (or expressives), words that describe how a speaker perceives a situation with the senses, and phonaesthemes, units like English gl-, which occur in many words that share a meaning component (in this case 'light': gleam, glitter, etc.). Furthermore, psychological experiments have shown that sound symbolism in one language can be understood by speakers of other languages, suggesting that some kinds of sound symbolism are universal. For further resources related to this article, please visit the WIREs website.

  6. Coupled Modeling of Hydrodynamics and Sound in Coastal Ocean for Renewable Ocean Energy Development

    SciTech Connect

    Long, Wen; Jung, Ki Won; Yang, Zhaoqing; Copping, Andrea; Deng, Z. Daniel

    2016-03-01

    An underwater sound model was developed to simulate sound propagation from marine and hydrokinetic energy (MHK) devices or offshore wind (OSW) energy platforms. Finite difference methods were developed to solve the 3D Helmholtz equation for sound propagation in the coastal environment. A 3D sparse matrix solver with complex coefficients was formed for solving the resulting acoustic pressure field. The Complex Shifted Laplacian Preconditioner (CSLP) method was applied to solve the matrix system iteratively with MPI parallelization using a high performance cluster. The sound model was then coupled with the Finite Volume Community Ocean Model (FVCOM) for simulating sound propagation generated by human activities, such as construction of OSW turbines or tidal stream turbine operations, in a range-dependent setting. As a proof of concept, initial validation of the solver is presented for two coastal wedge problems. This sound model can be useful for evaluating impacts on marine mammals due to deployment of MHK devices and OSW energy platforms.

  7. Sound Wave Energy Resulting from the Impact of Water Drops on the Soil Surface.

    PubMed

    Ryżak, Magdalena; Bieganowski, Andrzej; Korbiel, Tomasz

    2016-01-01

    The splashing of water drops on a soil surface is the first step of water erosion. There have been many investigations into splashing-most are based on recording and analysing images taken with high-speed cameras, or measuring the mass of the soil moved by splashing. Here, we present a new aspect of the splash phenomenon's characterization the measurement of the sound pressure level and the sound energy of the wave that propagates in the air. The measurements were carried out for 10 consecutive water drop impacts on the soil surface. Three soils were tested (Endogleyic Umbrisol, Fluvic Endogleyic Cambisol and Haplic Chernozem) with four initial moisture levels (pressure heads: 0.1 kPa, 1 kPa, 3.16 kPa and 16 kPa). We found that the values of the sound pressure and sound wave energy were dependent on the particle size distribution of the soil, less dependent on the initial pressure head, and practically the same for subsequent water drops (from the first to the tenth drop). The highest sound pressure level (and the greatest variability) was for Endogleyic Umbrisol, which had the highest sand fraction content. The sound pressure for this soil increased from 29 dB to 42 dB with the next incidence of drops falling on the sample The smallest (and the lowest variability) was for Fluvic Endogleyic Cambisol which had the highest clay fraction. For all experiments the sound pressure level ranged from ~27 to ~42 dB and the energy emitted in the form of sound waves was within the range of 0.14 μJ to 5.26 μJ. This was from 0.03 to 1.07% of the energy of the incident drops.

  8. Sound Wave Energy Resulting from the Impact of Water Drops on the Soil Surface

    PubMed Central

    Ryżak, Magdalena; Bieganowski, Andrzej; Korbiel, Tomasz

    2016-01-01

    The splashing of water drops on a soil surface is the first step of water erosion. There have been many investigations into splashing–most are based on recording and analysing images taken with high-speed cameras, or measuring the mass of the soil moved by splashing. Here, we present a new aspect of the splash phenomenon’s characterization the measurement of the sound pressure level and the sound energy of the wave that propagates in the air. The measurements were carried out for 10 consecutive water drop impacts on the soil surface. Three soils were tested (Endogleyic Umbrisol, Fluvic Endogleyic Cambisol and Haplic Chernozem) with four initial moisture levels (pressure heads: 0.1 kPa, 1 kPa, 3.16 kPa and 16 kPa). We found that the values of the sound pressure and sound wave energy were dependent on the particle size distribution of the soil, less dependent on the initial pressure head, and practically the same for subsequent water drops (from the first to the tenth drop). The highest sound pressure level (and the greatest variability) was for Endogleyic Umbrisol, which had the highest sand fraction content. The sound pressure for this soil increased from 29 dB to 42 dB with the next incidence of drops falling on the sample The smallest (and the lowest variability) was for Fluvic Endogleyic Cambisol which had the highest clay fraction. For all experiments the sound pressure level ranged from ~27 to ~42 dB and the energy emitted in the form of sound waves was within the range of 0.14 μJ to 5.26 μJ. This was from 0.03 to 1.07% of the energy of the incident drops. PMID:27388276

  9. Energetics of the Ocean's Infrasonic Sound Field.

    NASA Astrophysics Data System (ADS)

    D'Spain, Gerald Lynden

    1990-01-01

    Simultaneous measurements of infrasonic (0.5-20 Hz) particle velocity and pressure made by the Marine Physical Laboratory's freely drifting, independent, and neutrally buoyant Swallow floats are analyzed in terms of the energetics of acoustic fields. The theory of acoustic field energetics is presented and compared to standard data analysis techniques. The properties of the potential and kinetic energy density spectra, and the active and reactive intensity spectra from two deep ocean deployments are discussed. Results indicate that for most of the background sound field data in the midwater column above 1.7 Hz, the potential and kinetic energy density spectra are approximately equal. In one experiment, this is a consequence of the fact that, away from the ocean boundaries, the sound field is locally spatially homogeneous. Spatial homogeneity also implies that the particle velocity cross spectral density matrix is purely real. Near the ocean bottom, the vertical spatial inhomogeneity is statistically significant between 0.6 Hz to 1.4 Hz and 7 Hz to 20 Hz. In the lower band, the pressure autospectrum decreases with increasing distance from the ocean bottom, whereas in the upper band, it increases due to the deep sound channel's ability to trap acoustic energy at the higher infrasonic frequencies. For ship signals, the signal-to-noise ratio in the active intensity magnitude spectrum is 3 to 6 dB greater than in either of the two energy density spectra due to the vector nature of acoustic intensity. Although smaller than the net horizontal flux density above a few hertz, a statistically significant net vertical flux density of energy occurs across the whole frequency band, from the ocean surface into the bottom. The net horizontal flux density for various discrete sources, e.g., a magnitude 4.1 earthquake, a blue whale, and ship -generated harmonic line sets, is discussed. The net horizontal flux density of the background sound field between 5 and 12 Hz may have been

  10. Virtual sound for virtual reality

    SciTech Connect

    Blattner, M.M. ||; Papp, A.L. III |

    1993-02-01

    The computational limitations of real-time interactive computing do not meet our requirements for producing realistic images for virtual reality in a convincing manner. Regardless of the real-time restrictions on virtual reality interfaces, the representations can be no better than the graphics. Computer graphics is still limited in its ability to generate complex objects such as landscapes and humans. Nevertheless, useful and convincing visualizations are made through a variety of techniques. The central theme of this article is that a similar situation is true with sound for virtual reality. It is beyond our abilityto create interactive soundscapes that create a faithful reproduction of real world sounds, however, by choosing one`s application carefully and using sound to enhance a display rather than only mimic real-world scenes, a very effective use of sound can be made.

  11. Virtual sound for virtual reality

    SciTech Connect

    Blattner, M.M. Cancer Center, Houston, TX . Dept. of Biomathematics Lawrence Livermore National Lab., CA California Univ., Davis, CA ); Papp, A.L. III Lawrence Livermore National Lab., CA )

    1993-02-01

    The computational limitations of real-time interactive computing do not meet our requirements for producing realistic images for virtual reality in a convincing manner. Regardless of the real-time restrictions on virtual reality interfaces, the representations can be no better than the graphics. Computer graphics is still limited in its ability to generate complex objects such as landscapes and humans. Nevertheless, useful and convincing visualizations are made through a variety of techniques. The central theme of this article is that a similar situation is true with sound for virtual reality. It is beyond our abilityto create interactive soundscapes that create a faithful reproduction of real world sounds, however, by choosing one's application carefully and using sound to enhance a display rather than only mimic real-world scenes, a very effective use of sound can be made.

  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. Acoustics: Motion controlled by sound

    NASA Astrophysics Data System (ADS)

    Neild, Adrian

    2016-09-01

    A simple technique has been developed that produces holograms made of sound waves. These acoustic landscapes are used to manipulate microscale objects, and offer great potential in medical imaging and selective heating. See Letter p.518

  14. Flow field and near and far sound field of a subsonic jet

    NASA Technical Reports Server (NTRS)

    Zaman, K. B. M. Q.

    1986-01-01

    Flow and sound field data are presented for a 2.54 cm diameter air jet at a Mach number of 0.50 and a Reynolds number of 300,000. Distributions of mean velocity, turbulence intensities, Reynolds stress, spectral components of turbulence as well as of the near field pressure, together with essential characteristics of the far field sound are reported. This detailed set of data for one particular flow, erstwhile unavailable in the literature, is expected to help promoote and calibrate subsonic jet noise theories. 'Source locations' in terms of the turbulence maxima, coupling between the entrainment dynamics and the near pressure field, the sound radiation paths, and the balance in mass, momentum and sound energy fluxes are discussed. The results suggest that the large scale coherent structures of the jet govern the 'source locations' by controlling the turbulence and also strongly influence the near field pressure fluctuations.

  15. Fleet Logistics Center, Puget Sound

    DTIC Science & Technology

    2012-08-01

    ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Supply Systems Command,Fleet Logistics Center, Puget Sound,467 W Street , Bremerton ,WA,98314-5100 8... Bremerton , WA Established: October 1967 Name Changes: Naval Supply Center Puget Sound, Fleet and Industrial Supply Center Puget...or Sasebo) deployed Ships in the Western Pacific (WestPac) Naval Base Kitsap at Bremerton and Bangor (NBK at Bremerton or Bangor) Navy Region

  16. Controlling sound with acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Cummer, Steven A.; Christensen, Johan; Alù, Andrea

    2016-03-01

    Acoustic metamaterials can manipulate and control sound waves in ways that are not possible in conventional materials. Metamaterials with zero, or even negative, refractive index for sound offer new possibilities for acoustic imaging and for the control of sound at subwavelength scales. The combination of transformation acoustics theory and highly anisotropic acoustic metamaterials enables precise control over the deformation of sound fields, which can be used, for example, to hide or cloak objects from incident acoustic energy. Active acoustic metamaterials use external control to create effective material properties that are not possible with passive structures and have led to the development of dynamically reconfigurable, loss-compensating and parity-time-symmetric materials for sound manipulation. Challenges remain, including the development of efficient techniques for fabricating large-scale metamaterial structures and converting laboratory experiments into useful devices. In this Review, we outline the designs and properties of materials with unusual acoustic parameters (for example, negative refractive index), discuss examples of extreme manipulation of sound and, finally, provide an overview of future directions in the field.

  17. Neural correlates of sound externalization.

    PubMed

    Callan, Akiko; Callan, Daniel E; Ando, Hiroshi

    2013-02-01

    When we listen to sounds through headphones without utilizing special transforms, sound sources seem to be located inside our heads. The sound sources are said to be lateralized to one side or the other to varying degree. This internal lateralization is different than sound source localization in the natural environment in which the sound is localized distal to the head. We used fMRI to investigate difference in neural responses between lateralization and localization. Individualized binaural recordings were used as externalized auditory stimuli and stereo recordings were used as internalized auditory stimuli. Brain activity was measured while 14 participants performed an active auditory localization task and while 12 participants performed a stimulus type identification task. Irrespective of the task condition, we observed enhanced activity in the bilateral posterior temporal gyri (pSTG) for the externalized stimuli relative to the internalized stimuli. Region of interest analysis indicated that both left and right pSTG were more sensitive to sound sources in contra- than ipsilateral hemifields. Moreover, greater back than front activity was also found in the left pSTG. Compared to impoverished spatial auditory stimuli, realistic spatial auditory stimuli enhance neural responses in the pSTG. This may be why we could observe contralateral hemifield preference in bilateral pSTG that many previous studies have failed to observe. Overall, the results indicate the importance of using ecologically valid stimuli for investigating neural processes in human cortex.

  18. Time dependent wave envelope finite difference analysis of sound propagation

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.

    1984-01-01

    A transient finite difference wave envelope formulation is presented for sound propagation, without steady flow. Before the finite difference equations are formulated, the governing wave equation is first transformed to a form whose solution tends not to oscillate along the propagation direction. This transformation reduces the required number of grid points by an order of magnitude. Physically, the transformed pressure represents the amplitude of the conventional sound wave. The derivation for the wave envelope transient wave equation and appropriate boundary conditions are presented as well as the difference equations and stability requirements. To illustrate the method, example solutions are presented for sound propagation in a straight hard wall duct and in a two dimensional straight soft wall duct. The numerical results are in good agreement with exact analytical results.

  19. Sound speed measurements in liquid oxygen-liquid nitrogen mixtures

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.; Mazel, D. S.

    1985-01-01

    The sound speed in liquid oxygen (LOX), liquid nitrogen (LN2), and five LOX-LN2 mixtures was measured by an ultrasonic pulse-echo technique at temperatures in the vicinity of -195.8C, the boiling point of N2 at a pressure of I atm. Under these conditions, the measurements yield the following relationship between sound speed in meters per second and LN2 content M in mole percent: c = 1009.05-1.8275M+0.0026507 M squared. The second speeds of 1009.05 m/sec plus or minus 0.25 percent for pure LOX and 852.8 m/sec plus or minus 0.32 percent for pure LN2 are compared with those reported by past investigators. Measurement of sound speed should prove an effective means for monitoring the contamination of LOX by Ln2.

  20. Sound Symbolism Facilitates Early Verb Learning

    ERIC Educational Resources Information Center

    Imai, Mutsumi; Kita, Sotaro; Nagumo, Miho; Okada, Hiroyuki

    2008-01-01

    Some words are sound-symbolic in that they involve a non-arbitrary relationship between sound and meaning. Here, we report that 25-month-old children are sensitive to cross-linguistically valid sound-symbolic matches in the domain of action and that this sound symbolism facilitates verb learning in young children. We constructed a set of novel…

  1. Sound Symbolic Word Learning in Written Context

    ERIC Educational Resources Information Center

    Parault, Susan J.

    2006-01-01

    Sound symbolism is the notion that the relation between word sounds and word meaning is not arbitrary for all words, but rather there is a subset of words in the world's languages for which sounds and their symbols have some degree of correspondence. This research investigates sound symbolism as a possible means of gaining semantic knowledge of…

  2. 46 CFR 298.14 - Economic soundness.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Economic soundness. 298.14 Section 298.14 Shipping... Eligibility § 298.14 Economic soundness. (a) Economic Evaluation. We shall not issue a Letter Commitment for... you seek Title XI financing or refinancing, will be economically sound. The economic soundness...

  3. 46 CFR 298.14 - Economic soundness.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 false Economic soundness. 298.14 Section 298.14 Shipping... Eligibility § 298.14 Economic soundness. (a) Economic Evaluation. We shall not issue a Letter Commitment for... you seek Title XI financing or refinancing, will be economically sound. The economic soundness...

  4. 27 CFR 9.151 - Puget Sound.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Puget Sound. 9.151 Section... Sound. (a) Name. The name of the viticultural area described in this section is “Puget Sound.” (b) Approved maps. The appropriate maps for determining the boundary of the Puget Sound viticultural area...

  5. 27 CFR 9.151 - Puget Sound.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Puget Sound. 9.151 Section... Sound. (a) Name. The name of the viticultural area described in this section is “Puget Sound.” (b) Approved maps. The appropriate maps for determining the boundary of the Puget Sound viticultural area...

  6. 27 CFR 9.151 - Puget Sound.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Puget Sound. 9.151 Section... Sound. (a) Name. The name of the viticultural area described in this section is “Puget Sound.” (b) Approved maps. The appropriate maps for determining the boundary of the Puget Sound viticultural area...

  7. 27 CFR 9.151 - Puget Sound.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Puget Sound. 9.151 Section... Sound. (a) Name. The name of the viticultural area described in this section is “Puget Sound.” (b) Approved maps. The appropriate maps for determining the boundary of the Puget Sound viticultural area...

  8. 27 CFR 9.151 - Puget Sound.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Puget Sound. 9.151 Section... Sound. (a) Name. The name of the viticultural area described in this section is “Puget Sound.” (b) Approved maps. The appropriate maps for determining the boundary of the Puget Sound viticultural area...

  9. Experimental difficulties in measuring the scattering of sound by sound

    SciTech Connect

    TenCate, J.A. )

    1994-11-01

    The question of whether one sound beam can interact with another at nonzero angle and scatter nonlinearly generated sound outside the mutual interaction region has been debated since the 1950s. Experimental work on this problem has left the question unresolved. This presentation describes experimental difficulties associated with measuring scattered sound produced by real diffracting primary beams. Optimal conditions for observing scattered sound, as outlined by Berntsen [ital et] [ital al]. [J. Acoust. Soc. Am. [bold 86], 1968 (1989)] and by Darvennes and Hamilton [J. Acoust. Soc. Am. [bold 87], 1955 (1990)], are reviewed in relation to the design of our own experiments. Our experiments were performed with either two uniform circular sources in water (megahertz frequencies), or with one circular source and the other a shaded source with lower sidelobes. A variety of primary frequency ratios, interaction angles, and other parameters were considered. Comparison of the primary beam patterns with measured sum and difference frequency field patterns reveals the difficulty in identifying which components of the latter correspond to scattered'' sound. It is concluded that two Gaussian-type sources with exceedingly good sidelobe suppression are needed to perform a reasonable experiment. [Work supported by the Packard Foundation and ONR.] [sup a]Present address: Earth and Environmental Sciences Division, Mail Stop D443, Los Alamos National Laboratory, Los Alamos, NM 87545.

  10. Can joint sound assess soft and hard endpoints of the Lachman test?: A preliminary study.

    PubMed

    Hattori, Koji; Ogawa, Munehiro; Tanaka, Kazunori; Matsuya, Ayako; Uematsu, Kota; Tanaka, Yasuhito

    2016-05-12

    The Lachman test is considered to be a reliable physical examination for anterior cruciate ligament (ACL) injury. Patients with a damaged ACL demonstrate a soft endpoint feeling. However, examiners judge the soft and hard endpoints subjectively. The purpose of our study was to confirm objective performance of the Lachman test using joint auscultation. Human and porcine knee joints were examined. Knee joint sound during the Lachman test (Lachman sound) was analyzed by fast Fourier transformation. As quantitative indices of Lachman sound, the peak sound as the maximum relative amplitude (acoustic pressure) and its frequency were used. The mean Lachman peak sound for healthy volunteer knees was 86.9 ± 12.9 Hz in frequency and -40 ± 2.5 dB in acoustic pressure. The mean Lachman peak sound for intact porcine knees was 84.1 ± 9.4 Hz and -40.5 ± 1.7 dB. Porcine knees with ACL deficiency had a soft endpoint feeling during the Lachman test. The Lachman peak sounds of porcine knees with ACL deficiency were dispersed into four distinct groups, with center frequencies of around 40, 160, 450, and 1600. The Lachman peak sound was capable of assessing soft and hard endpoints of the Lachman test objectively.

  11. Tracheal Sounds Acquisition Using Smartphones

    PubMed Central

    Reyes, Bersain A.; Reljin, Natasa; Chon, Ki H.

    2014-01-01

    Tracheal sounds have received a lot of attention for estimating ventilation parameters in a non-invasive way. The aim of this work was to examine the feasibility of extracting accurate airflow, and automating the detection of breath-phase onset and respiratory rates all directly from tracheal sounds acquired from an acoustic microphone connected to a smartphone. We employed the Samsung Galaxy S4 and iPhone 4s smartphones to acquire tracheal sounds from N = 9 healthy volunteers at airflows ranging from 0.5 to 2.5 L/s. We found that the amplitude of the smartphone-acquired sounds was highly correlated with the airflow from a spirometer, and similar to previously-published studies, we found that the increasing tracheal sounds' amplitude as flow increases follows a power law relationship. Acquired tracheal sounds were used for breath-phase onset detection and their onsets differed by only 52 ± 51 ms (mean ± SD) for Galaxy S4, and 51 ± 48 ms for iPhone 4s, when compared to those detected from the reference signal via the spirometer. Moreover, it was found that accurate respiratory rates (RR) can be obtained from tracheal sounds. The correlation index, bias and limits of agreement were r2 = 0.9693, 0.11 (−1.41 to 1.63) breaths-per-minute (bpm) for Galaxy S4, and r2 = 0.9672, 0.097 (–1.38 to 1.57) bpm for iPhone 4s, when compared to RR estimated from spirometry. Both smartphone devices performed similarly, as no statistically-significant differences were found. PMID:25196108

  12. Sound propagation from a ridge wind turbine across a valley.

    PubMed

    Van Renterghem, Timothy

    2017-04-13

    Sound propagation outdoors can be strongly affected by ground topography. The existence of hills and valleys between a source and receiver can lead to the shielding or focusing of sound waves. Such effects can result in significant variations in received sound levels. In addition, wind speed and air temperature gradients in the atmospheric boundary layer also play an important role. All of the foregoing factors can become especially important for the case of wind turbines located on a ridge overlooking a valley. Ridges are often selected for wind turbines in order to increase their energy capture potential through the wind speed-up effects often experienced in such locations. In this paper, a hybrid calculation method is presented to model such a case, relying on an analytical solution for sound diffraction around an impedance cylinder and the conformal mapping (CM) Green's function parabolic equation (GFPE) technique. The various aspects of the model have been successfully validated against alternative prediction methods. Example calculations with this hybrid analytical-CM-GFPE model show the complex sound pressure level distribution across the valley and the effect of valley ground type. The proposed method has the potential to include the effect of refraction through the inclusion of complex wind and temperature fields, although this aspect has been highly simplified in the current simulations.This article is part of the themed issue 'Wind energy in complex terrains'.

  13. Interaction of Sound from Supersonic Jets with Nearby Structures

    NASA Technical Reports Server (NTRS)

    Fenno, C. C., Jr.; Bayliss, A.; Maestrello, L.

    1997-01-01

    A model of sound generated in an ideally expanded supersonic (Mach 2) jet is solved numerically. Two configurations are considered: (1) a free jet and (2) an installed jet with a nearby array of flexible aircraft type panels. In the later case the panels vibrate in response to loading by sound from the jet and the full coupling between the panels and the jet is considered, accounting for panel response and radiation. The long time behavior of the jet is considered. Results for near field and far field disturbance, the far field pressure and the vibration of and radiation from the panels are presented. Panel response crucially depends on the location of the panels. Panels located upstream of the Mach cone are subject to a low level, nearly continuous spectral excitation and consequently exhibit a low level, relatively continuous spectral response. In contrast, panels located within the Mach cone are subject to a significant loading due to the intense Mach wave radiation of sound and exhibit a large, relatively peaked spectral response centered around the peak frequency of sound radiation. The panels radiate in a similar fashion to the sound in the jet, in particular exhibiting a relatively peaked spectral response at approximately the Mach angle from the bounding wall.

  14. Sound speed criterion for two-phase critical flow

    NASA Astrophysics Data System (ADS)

    Chung, M.-S.; Park, S.-B.; Lee, H.-K.

    2004-09-01

    Critical flow simulation for non-homogeneous, non-equilibrium two-phase flows is improved by applying a new sound speed model which is derived from the characteristic analysis of hyperbolic two-fluid model. The hyperbolicity of two-fluid model was based on the concept of surface tension for the interfacial pressure jump terms in the momentum equations. Real eigenvalues obtained as the closed-form solution of characteristic polynomial represent the sound speeds in the bubbly flow regime that agree well with the existing experimental data. The analytic sound speed is consistent with that obtained by the earlier study of Nguyen et al. though there is a difference between them especially in the limiting condition. The present sound speed shows more reasonable result in that condition than Nguyen et al.'s does. The present critical flow criterion derived by the present sound speed is employed in the MARS code and is assessed by treating several nozzle flow tests. The assessment results, without any adjustment made by some discharge coefficients, demonstrate more accurate predictions of critical flow rate than those of the earlier critical flow calculations in the bubbly flow regime.

  15. Production of Two Nasal Sounds by Speakers With Cleft Palate.

    PubMed

    Bressmann, Tim; Radovanovic, Bojana; Harper, Susan; Klaiman, Paula; Fisher, David; Kulkarni, Gajanan V

    2016-12-29

    Manyspeakers with cleft palate develop atypical consonant productions, especially for pressure consonants such as plosives, fricatives, and affricates. The present study investigated the nature of nasal sound errors. The participants were eight female and three male speakers with cleft palate between the ages of 6 to 20. Speakers were audio-recorded, and midsagittal tongue movement was captured with ultrasound. The speakers repeated vowel-consonant-vowel with the vowels /α/, /i/, and /u/ and the alveolar and velar nasal consonants /n/ and //. The productions were reviewed by three listeners. The participants showed a variety of different placement errors and insertions of plosives, as well as liquid productions. There was considerable error variability between and within speakers, often related to the different vowel contexts. Three speakers co-produced click sounds. The study demonstrated the wide variety of sound errors that some speakers with cleft palate may demonstrate for nasal sounds. Nasal sounds, ideally in different vowel contexts, should be included in articulation screenings for speakers with cleft palate, perhaps more than is currently the case.

  16. Robust Feedback Control of Flow Induced Structural Radiation of Sound

    NASA Technical Reports Server (NTRS)

    Heatwole, Craig M.; Bernhard, Robert J.; Franchek, Matthew A.

    1997-01-01

    A significant component of the interior noise of aircraft and automobiles is a result of turbulent boundary layer excitation of the vehicular structure. In this work, active robust feedback control of the noise due to this non-predictable excitation is investigated. Both an analytical model and experimental investigations are used to determine the characteristics of the flow induced structural sound radiation problem. The problem is shown to be broadband in nature with large system uncertainties associated with the various operating conditions. Furthermore the delay associated with sound propagation is shown to restrict the use of microphone feedback. The state of the art control methodologies, IL synthesis and adaptive feedback control, are evaluated and shown to have limited success for solving this problem. A robust frequency domain controller design methodology is developed for the problem of sound radiated from turbulent flow driven plates. The control design methodology uses frequency domain sequential loop shaping techniques. System uncertainty, sound pressure level reduction performance, and actuator constraints are included in the design process. Using this design method, phase lag was added using non-minimum phase zeros such that the beneficial plant dynamics could be used. This general control approach has application to lightly damped vibration and sound radiation problems where there are high bandwidth control objectives requiring a low controller DC gain and controller order.

  17. Environmental quality of Long Island Sound: Assessment and management issues

    SciTech Connect

    Wolfe, D.A.; Farrow, D.R.G.; Robertson, A. ); Monahan, R. ); Stacey, P.E. )

    1991-09-01

    Estimated pollutant loadings to Long Island Sound (LIS) are presented and discussed in the context of current information on population trends and land-use characteristics within the drainage basin of the sound. For the conventional pollutants (BOD, N, and P) and for most of the metals examined, the fluxes to LIS from wastewater treatment plants approach or exceed the fluxes from riverine sources. Urban runoff is a significant source for only a few contaminants, such as lead and petroleum hydrocarbons. Atmospheric flux estimates made for other areas are extrapolated to LIS, and this source appears to be significant for lead, zinc, and polynuclear aromatic hydrocarbons, and chlorinated pesticides. Continued population growth is projected through 2010, both in the urban centers of the western sound and in the coastal counties surrounding the central and eastern portions of LIS. This growth will place increased pollution pressure on the sound and increased demands on already scarce coastal and estuarine land-use categories. Close interaction between environmental planners, managers, and scientists is required to identify effective control strategies for reducing existing pollutant stress to the sound and for minimizing the effects of future development.

  18. Sound field measurement in a double layer cavitation cluster by rugged miniature needle hydrophones.

    PubMed

    Koch, Christian

    2016-03-01

    During multi-bubble cavitation the bubbles tend to organize themselves into clusters and thus the understanding of properties and dynamics of clustering is essential for controlling technical applications of cavitation. Sound field measurements are a potential technique to provide valuable experimental information about the status of cavitation clouds. Using purpose-made, rugged, wide band, and small-sized needle hydrophones, sound field measurements in bubble clusters were performed and time-dependent sound pressure waveforms were acquired and analyzed in the frequency domain up to 20 MHz. The cavitation clusters were synchronously observed by an electron multiplying charge-coupled device (EMCCD) camera and the relation between the sound field measurements and cluster behaviour was investigated. Depending on the driving power, three ranges could be identified and characteristic properties were assigned. At low power settings no transient and no or very low stable cavitation activity can be observed. The medium range is characterized by strong pressure peaks and various bubble cluster forms. At high power a stable double layer was observed which grew with further increasing power and became quite dynamic. The sound field was irregular and the fundamental at driving frequency decreased. Between the bubble clouds completely different sound field properties were found in comparison to those in the cloud where the cavitation activity is high. In between the sound field pressure amplitude was quite small and no collapses were detected.

  19. Controlled sound field with a dual layer loudspeaker array

    NASA Astrophysics Data System (ADS)

    Shin, Mincheol; Fazi, Filippo M.; Nelson, Philip A.; Hirono, Fabio C.

    2014-08-01

    Controlled sound interference has been extensively investigated using a prototype dual layer loudspeaker array comprised of 16 loudspeakers. Results are presented for measures of array performance such as input signal power, directivity of sound radiation and accuracy of sound reproduction resulting from the application of conventional control methods such as minimization of error in mean squared pressure, maximization of energy difference and minimization of weighted pressure error and energy. Procedures for selecting the tuning parameters have also been introduced. With these conventional concepts aimed at the production of acoustically bright and dark zones, all the control methods used require a trade-off between radiation directivity and reproduction accuracy in the bright zone. An alternative solution is proposed which can achieve better performance based on the measures presented simultaneously by inserting a low priority zone named as the “gray” zone. This involves the weighted minimization of mean-squared errors in both bright and dark zones together with the gray zone in which the minimization error is given less importance. This results in the production of directional bright zone in which the accuracy of sound reproduction is maintained with less required input power. The results of simulations and experiments are shown to be in excellent agreement.

  20. Sound Transmission Validation and Sensitivity Studies in Numerical Models.

    PubMed

    Oberrecht, Steve P; Krysl, Petr; Cranford, Ted W

    2016-01-01

    In 1974, Norris and Harvey published an experimental study of sound transmission into the head of the bottlenose dolphin. We used this rare source of data to validate our Vibroacoustic Toolkit, an array of numerical modeling simulation tools. Norris and Harvey provided measurements of received sound pressure in various locations within the dolphin's head from a sound source that was moved around the outside of the head. Our toolkit was used to predict the curves of pressure with the best-guess input data (material properties, transducer and hydrophone locations, and geometry of the animal's head). In addition, we performed a series of sensitivity analyses (SAs). SA is concerned with understanding how input changes to the model influence the outputs. SA can enhance understanding of a complex model by finding and analyzing unexpected model behavior, discriminating which inputs have a dominant effect on particular outputs, exploring how inputs combine to affect outputs, and gaining insight as to what additional information improves the model's ability to predict. Even when a computational model does not adequately reproduce the behavior of a physical system, its sensitivities may be useful for developing inferences about key features of the physical system. Our findings may become a valuable source of information for modeling the interactions between sound and anatomy.

  1. Characterizing and Classifying Acoustical Ambient Sound Profiles

    DTIC Science & Technology

    2015-03-26

    of sound . The value for the speed of sound varies depending on the medium which the sound wave travels through as well as the temperature and...Characterizing and Classifying Acoustical Ambient Sound Profiles THESIS MARCH 2015 Paul T. Gaski, Second Lieutenant, USAF AFIT-ENS-MS-15-M-122... SOUND PROFILES THESIS Presented to the Faculty Department of Operational Sciences Graduate School of Engineering and Management Air Force Institute of

  2. Sounds of silence: How to animate virtual worlds with sound

    NASA Technical Reports Server (NTRS)

    Astheimer, Peter

    1993-01-01

    Sounds are an integral and sometimes annoying part of our daily life. Virtual worlds which imitate natural environments gain a lot of authenticity from fast, high quality visualization combined with sound effects. Sounds help to increase the degree of immersion for human dwellers in imaginary worlds significantly. The virtual reality toolkit of IGD (Institute for Computer Graphics) features a broad range of standard visual and advanced real-time audio components which interpret an object-oriented definition of the scene. The virtual reality system 'Virtual Design' realized with the toolkit enables the designer of virtual worlds to create a true audiovisual environment. Several examples on video demonstrate the usage of the audio features in Virtual Design.

  3. Sounds of a Star

    NASA Astrophysics Data System (ADS)

    2001-06-01

    Acoustic Oscillations in Solar-Twin "Alpha Cen A" Observed from La Silla by Swiss Team Summary Sound waves running through a star can help astronomers reveal its inner properties. This particular branch of modern astrophysics is known as "asteroseismology" . In the case of our Sun, the brightest star in the sky, such waves have been observed since some time, and have greatly improved our knowledge about what is going on inside. However, because they are much fainter, it has turned out to be very difficult to detect similar waves in other stars. Nevertheless, tiny oscillations in a solar-twin star have now been unambiguously detected by Swiss astronomers François Bouchy and Fabien Carrier from the Geneva Observatory, using the CORALIE spectrometer on the Swiss 1.2-m Leonard Euler telescope at the ESO La Silla Observatory. This telescope is mostly used for discovering exoplanets (see ESO PR 07/01 ). The star Alpha Centauri A is the nearest star visible to the naked eye, at a distance of a little more than 4 light-years. The new measurements show that it pulsates with a 7-minute cycle, very similar to what is observed in the Sun . Asteroseismology for Sun-like stars is likely to become an important probe of stellar theory in the near future. The state-of-the-art HARPS spectrograph , to be mounted on the ESO 3.6-m telescope at La Silla, will be able to search for oscillations in stars that are 100 times fainter than those for which such demanding observations are possible with CORALIE. PR Photo 23a/01 : Oscillations in a solar-like star (schematic picture). PR Photo 23b/01 : Acoustic spectrum of Alpha Centauri A , as observed with CORALIE. Asteroseismology: listening to the stars ESO PR Photo 23a/01 ESO PR Photo 23a/01 [Preview - JPEG: 357 x 400 pix - 96k] [Normal - JPEG: 713 x 800 pix - 256k] [HiRes - JPEG: 2673 x 3000 pix - 2.1Mb Caption : PR Photo 23a/01 is a graphical representation of resonating acoustic waves in the interior of a solar-like star. Red and blue

  4. Influence of sound source width on human sound localization.

    PubMed

    Greene, Nathaniel T; Paige, Gary D

    2012-01-01

    Free-field sound localization experiments generally assume that a loudspeaker can be approximated by a point-source; however, a large loudspeaker may extend beyond the width that two sources can be discriminated. Humans can accurately discriminate sound source locations within a few degrees, thus one might expect localization precision to decrease as a function of sound source diameter, much as precision is lower for localizing the center of a wide, blurry light source. In order to test the degree to which humans differentially localize small and large sound sources, auditory targets were presented using a single 25.4 cm by 10.2 cm elliptical loudspeaker with the primary axis oriented both horizontally and vertically in different sessions. Subjects were seated with their heads fixed by a bite bar in a darkened, echo-attenuating room facing a cylindrical, acoustically transparent screen at a distance of 2 meters. Auditory targets consisted of repeating bursts (5 Hz) of low frequency band-pass noise (0.2 - 1 kHz, 75 dB SPL). Subjects were instructed to quickly and accurately guide a laser pointer mounted on a cylindrical joystick towards targets, presented randomly within a field ± 40° in azimuth by ± 10° in elevation, with oversampled points located every ten degrees along the primary meridians. Localization accuracy and precision (mean and standard deviation of localization error at oversampled locations) were not significantly different between speaker orientations, and were comparable to baseline measurements recorded using a 7.6 cm circular speaker. We conclude that low frequency sound localization performance is not dependent upon the size of the sound source as predicted theoretically, and is well approximated by a point source.

  5. A fluidic sounding rocket motor ignition system.

    NASA Technical Reports Server (NTRS)

    Marchese, V. P.; Rakowsky, E. L.; Bement, L. J.

    1972-01-01

    Fluidic sounding rocket motor ignition has been found to be feasible using a system without stored energy and with the complete absence of electrical energy and wiring. The fluidic ignitor is based on a two component aerodynamic resonance heating device called the pneumatic match. Temperatures in excess of 600 C were generated in closed resonance tubes which were excited by a free air jet from a simple convergent nozzle. Using nitrocellulose interface material, ignition of boron potassium nitrate was accomplished with air supply pressures as low as 45 psi. This paper describes an analytical and experimental program which established a fluidic rocket motor ignition system concept incorporating a pneumatic match with a simple hand pump as the only energy source.

  6. Acoustic pathways revealed: simulated sound transmission and reception in Cuvier's beaked whale (Ziphius cavirostris).

    PubMed

    Cranford, Ted W; Krysl, Petr; Hildebrand, John A

    2008-03-01

    The finite element modeling (FEM) space reported here contains the head of a simulated whale based on CT data sets as well as physical measurements of sound-propagation characteristics of actual tissue samples. Simulated sound sources placed inside and outside of an adult male Cuvier's beaked whale (Ziphius cavirostris) reveal likely sound propagation pathways into and out of the head. Two separate virtual sound sources that were located at the left and right phonic lips produced beams that converged just outside the head. This result supports the notion that dual sound sources can interfere constructively to form a biologically useful and, in fact, excellent sonar beam in front of the animal. The most intriguing FEM results concern pathways by which sounds reach the ears. The simulations reveal a previously undescribed 'gular pathway' for sound reception in Ziphius. Propagated sound pressure waves enter the head from below and between the lower jaws, pass through an opening created by the absence of the medial bony wall of the posterior mandibles, and continue toward the bony ear complexes through the internal mandibular fat bodies. This new pathway has implications for understanding the evolution of underwater hearing in odontocetes. Our model also provides evidence for receive beam directionality, off-axis acoustic shadowing and a plausible mechanism for the long-standing orthodox sound reception pathway in odontocetes. The techniques developed for this study can be used to study acoustic perturbation in a wide variety of marine organisms.

  7. Velocity controlled sound field reproduction by non-uniformly spaced loudspeakers

    NASA Astrophysics Data System (ADS)

    Shin, Mincheol; Nelson, Philip A.; Fazi, Filippo M.; Seo, Jeongil

    2016-05-01

    One approach to the reproduction of a sound field is to ensure the reproduction of the acoustic pressure on the surface bounding the volume within which reproduction is sought. However, this approach suffers from technical limitations when the loudspeakers used for the reproduction of the surface acoustic pressures are unevenly spaced. It is shown in this paper that sound field reproduction with a spatially non-uniform loudspeaker arrangement can be considerably improved by changing the physical quantity to be controlled on the bounding surface from pressure to particle velocity. One of the main advantages of the velocity control method is the simplicity with which the inverse problem can be regularized, irrespective of the direction of arrival of the sound to be reproduced. In addition, the velocity controlled sound field shows better reproduction of the time averaged intensity flow in the reproduction region which in turn appears to be closely linked with better human perception of sound localization. Furthermore, the proposed method results in smoother "panning functions" that describe the variation of the source outputs as a function of the angle of incidence of the sound to be reproduced. The performance of the velocity matching method has been evaluated by comparison to the conventional pressure matching method and through simulations with several non-uniform loudspeaker layouts. The simulated results were also verified with experiments and subjective tests.

  8. Effects of sounds generated by a dental turbine and a stream on regional cerebral blood flow and cardiovascular responses.

    PubMed

    Mishima, Riho; Kudo, Takumu; Tsunetsugu, Yuko; Miyazaki, Yoshifumi; Yamamura, Chie; Yamada, Yoshiaki

    2004-09-01

    Effects of sound generated by a dental turbine and a small stream (murmur) and the effects of no sound (null, control) on heart rate, systolic and diastolic blood pressure, and hemodynamic changes (oxygenated, deoxygenated, and total hemoglobin concentrations) in the frontal cortex were measured in 18 young volunteers. Questionnaires completed by the volunteers were also evaluated. Near-infrared spectroscopy and the Finapres technique were employed to measure hemodynamic and vascular responses, respectively. The subjects assessed the murmur, null, and turbine sounds as "pleasant," "natural," and "unpleasant," respectively. Blood pressures changed in response to the murmur, null, and turbine sound stimuli as expected: lower than the control level, unchanged, and higher than the control level, respectively. Mean blood pressure values tended to increase gradually over the recording time even during the null sound stimulation, possibly because of the recording environment. Oxygenated hemoglobin concentrations decreased drastically in response to the dental turbine sound, while deoxygenated hemoglobin concentrations remained unchanged and thus total hemoglobin concentrations decreased (due to the decreased oxygenated hemoglobin concentrations). Hemodynamic responses to the murmuring sound and the null sound were slight or unchanged, respectively. Surprisingly, heart rate measurements remained fairly stable in response to the stimulatory noises. In conclusion, we demonstrate here that sound generated by a dental turbine may affect cerebral blood flow and metabolism as well as autonomic responses.

  9. Thermodynamic properties of nitrogen gas from sound velocity measurements

    NASA Technical Reports Server (NTRS)

    Younglove, B. A.

    1979-01-01

    Thermodynamic properties of nitrogen gas have been calculated from 80 K to 350 K and at pressures to 10 bar from sound velocity measurements and existing P-V-T data using multiproperty fitting techniques. These new data are intended to improve existing predictive capability of the equation of state in the low density region needed for use with the NASA-Langley National Transonics Facility.

  10. Enhancement of Far Field Sound Levels by Refractive Focusing

    NASA Technical Reports Server (NTRS)

    Thomson, D. W.; Roth, S. D.

    1981-01-01

    The enhancement of sound pressure levels resulting from refractive focusing was calculated for meteorological conditions representative of those observed at the MOD-1 site near Boone, N.C. The results show that 10 to 20dB enhancements can occur over ranges of several hundred meters. Localized enhancements in excess of 20dB can occur but will probably be of limited duration as a consequence of normal temporally varying meteorological conditions.

  11. Acoustic metamaterials for sound mitigation

    NASA Astrophysics Data System (ADS)

    Assouar, Badreddine; Oudich, Mourad; Zhou, Xiaoming

    2016-05-01

    We provide theoretical and numerical analyses of the behavior of a plate-type acoustic metamaterial considered in an air-borne sound environment in view of sound mitigation application. Two configurations of plate are studied, a spring-mass one and a pillar system-based one. The acoustic performances of the considered systems are investigated with different approaches and show that a high sound transmission loss (STL) up to 82 dB is reached with a metamaterial plate with a thickness of 0.5 mm. The physical understanding of the acoustic behavior of the metamaterial partition is discussed based on both air-borne and structure-borne approaches. Confrontation between the STL, the band structure, the displacement fields and the effective mass density of the plate metamaterial is made to have a complete physical understanding of the different mechanisms involved.

  12. Sound propagation in choked ducts

    NASA Technical Reports Server (NTRS)

    Hersh, A. S.; Liu, C. Y.

    1976-01-01

    The linearized equations describing the propagation of sound in variable area ducts containing flow are shown to be singular when the duct mean flow is sonic. The singularity is removed when previously ignored nonlinear terms are retained. The results of a numerical study, for the case of plane waves propagating in a one-dimensional converging-diverging duct, show that the sound field is adequately described by the linearized equations only when the axial mean flow Mach number at the duct throat M sub th 0.6. For M sub th 0.6, the numerical results showed that acoustic energy flux was not conserved. An attempt was made to extend the study to include the nonlinear behavior of the sound field. Meaningful results were not obtained due, primarily, to numerical difficulties.

  13. Review of sound card photogates

    NASA Astrophysics Data System (ADS)

    Gingl, Zoltán; Mingesz, Róbert; Makra, Péter; Mellár, János

    2011-07-01

    Photogates are probably the most commonly used electronic instruments to aid experiments in the field of mechanics. Although they are offered by many manufacturers, they can be too expensive to be widely used in all classrooms, in multiple experiments or even at home experimentation. Today all computers have a sound card--an interface for analogue signals. It is possible to make very simple yet highly accurate photogates for cents, while much more sophisticated solutions are also available at a still very low cost. In our paper we show several experimentally tested ways of implementing sound card photogates in detail, and we also provide full-featured, free, open-source photogate software as a much more efficient experimentation tool than the usually used sound recording programs. Further information is provided on a dedicated web page, www.noise.physx.u-szeged.hu/edudev.

  14. Atmospheric Physics and Sound Propagation

    DTIC Science & Technology

    1950-09-01

    exposures of ’ssh.ite mica, various insects and bacteria to the intense, sound field» %£te " mice are killed in osae minute» The killing lias been...tensity sound on a species of sporeforming bacteria » It is possible to obtain very high intensities in water in a flask.;Suspend’ed over the siren...hinges and closure are standard refrigerator~type units» There i3 a double sponge rubber seal around the doors« Electrical connection to

  15. Save Our Sounds: America's Recorded Sound Heritage Project.

    ERIC Educational Resources Information Center

    Marian, Beth Ann, Ed.; Rosenberg, Jessica, Ed.

    2002-01-01

    The Fall 2002 Idea Book contains suggestions for enriched learning. "Save Our History; Save Our Sounds,""Eureka!" and "Lindbergh Flies Again" involve two or more disciplines of study and would work well for team-teaching projects . Lesson materials from the Arts and Entertainment Network teacher's guide are:…

  16. The Multisensory Sound Lab: Sounds You Can See and Feel.

    ERIC Educational Resources Information Center

    Lederman, Norman; Hendricks, Paula

    1994-01-01

    A multisensory sound lab has been developed at the Model Secondary School for the Deaf (District of Columbia). A special floor allows vibrations to be felt, and a spectrum analyzer displays frequencies and harmonics visually. The lab is used for science education, auditory training, speech therapy, music and dance instruction, and relaxation…

  17. Parameterizing Sound: Design Considerations for an Environmental Sound Database

    DTIC Science & Technology

    2015-04-01

    source categorization, acoustics , psychophysics 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 28 19a...multifaceted problem. To move from conceptualization to implementation, experts in psychology, acoustics , linguistics, software engineering, and user...collection of individual descriptive acoustic features but are defined by the listener in the context of the event that produced the sound they are

  18. Sound preferences in urban open public spaces

    NASA Astrophysics Data System (ADS)

    Kang, Jian; Yang, Wei

    2003-10-01

    This paper studies people's perception of sound, based on an intensive questionnaire survey in fourteen urban open public spaces of five European countries. The questionnaire includes identification of recognized sounds, classification of sound preference, and indication of wanted and unwanted sounds. The results indicate three facets to people's sound preferences. First, people generally prefer natural and culture-related sounds rather than artificial sounds. Vehicle sounds and construction sounds are regarded as the most unpopular, whereas sounds from human activities are normally rated as neutral. Second, cultural background and long-term environmental experience play an important role in people's judgment of sound preference. People from a similar environment may show a similar tendency on their sound preferences, which can be defined as macro-preference. Third, personal differences, such as age and gender, further influence people's sound preference, which can be defined as micro-preference. For example, with increasing age, a higher percentage of people are favorable to, or tolerate, sounds relating to nature, culture or human activities. Male and female exhibit only slight differences. [Work supported by the European Commission.

  19. Congruent sound can modulate odor pleasantness.

    PubMed

    Seo, Han-Seok; Lohse, Franziska; Luckett, Curtis R; Hummel, Thomas

    2014-03-01

    This study aimed to determine 1) whether certain background sounds can be matched with specific odors and 2) whether the background sounds can increase pleasantness for their congruent odors. In Experiment 1, congruent sounds increased odor pleasantness, but not odor intensity, significantly more than incongruent sounds. Experiment 2 demonstrated that certain background sounds can be paired with specific odors. For example, cinnamon, clove, and orange odors were rated significantly more congruent with a Christmas carol compared with the sound of brushing teeth and/or the beach sound. The congruent sounds increased odor pleasantness significantly more than incongruent sounds. Similarly, the congruent sound-induced odor pleasantness was observed in Experiment 3. As participants judged the pair of odor and sound to be more congruent, they rated the odor significantly more pleasant. Congruent sound assisted participants in identifying and in being familiar with the odor, thereby leading to an increase in odor pleasantness. However, the congruent sound-induced odor pleasantness was not obtained in all odors. In conclusion, this study provides new empirical evidence that pleasantness ratings for odors can increase in the presence of their congruent sounds.

  20. Optical remote sensing of sound in the ocean

    NASA Astrophysics Data System (ADS)

    Churnside, James H.; Naugolnykh, Konstantin; Marchbanks, Richard D.

    2014-05-01

    We are proposing a novel remote sensing technique to measure sound in the upper ocean. The objective is a system that can be flown on an aircraft. Conventional acoustic sensors are ineffective in this application, because almost none (~ 0.1 %) of the sound in the ocean is transmitted through the water/air interface. The technique is based on the acoustic modulation of bubbles near the sea surface. It is clear from the ideal gas law that the volume of a bubble will decrease if the pressure is increased, as long as the number of gas molecules and temperature remain constant. The pressure variations associated with the acoustic field will therefore induce proportional volume fluctuations of the insonified bubbles. The lidar return from a collection of bubbles has been shown to be proportional to the total void fraction, independent of the bubble size distribution. This implies that the lidar return from a collection of insonified bubbles will be modulated at the acoustic frequencies, independent of the bubble size distribution. Moreover, that modulation is linearly related to the sound pressure. The basic principles have been demonstrated in the laboratory, and these results will be presented. Estimates of signal-to-noise ratio suggest that the technique should work in the open ocean. Design considerations and signal-to-noise ratios will also be presented.

  1. Vocal Imitations of Non-Vocal Sounds

    PubMed Central

    Houix, Olivier; Voisin, Frédéric; Misdariis, Nicolas; Susini, Patrick

    2016-01-01

    Imitative behaviors are widespread in humans, in particular whenever two persons communicate and interact. Several tokens of spoken languages (onomatopoeias, ideophones, and phonesthemes) also display different degrees of iconicity between the sound of a word and what it refers to. Thus, it probably comes at no surprise that human speakers use a lot of imitative vocalizations and gestures when they communicate about sounds, as sounds are notably difficult to describe. What is more surprising is that vocal imitations of non-vocal everyday sounds (e.g. the sound of a car passing by) are in practice very effective: listeners identify sounds better with vocal imitations than with verbal descriptions, despite the fact that vocal imitations are inaccurate reproductions of a sound created by a particular mechanical system (e.g. a car driving by) through a different system (the voice apparatus). The present study investigated the semantic representations evoked by vocal imitations of sounds by experimentally quantifying how well listeners could match sounds to category labels. The experiment used three different types of sounds: recordings of easily identifiable sounds (sounds of human actions and manufactured products), human vocal imitations, and computational “auditory sketches” (created by algorithmic computations). The results show that performance with the best vocal imitations was similar to the best auditory sketches for most categories of sounds, and even to the referent sounds themselves in some cases. More detailed analyses showed that the acoustic distance between a vocal imitation and a referent sound is not sufficient to account for such performance. Analyses suggested that instead of trying to reproduce the referent sound as accurately as vocally possible, vocal imitations focus on a few important features, which depend on each particular sound category. These results offer perspectives for understanding how human listeners store and access long

  2. ECN Pressure Test

    SciTech Connect

    Dixon, K.; /Fermilab

    1991-07-18

    This note describes: the rationale for the test pressure of the inner ECN cryostat vessel, the equipment to be used in this test, the test procedure, the status of the vessel prior to the test, the actual test results, and a schematic diagram of the testing set up and the pressure testing permit. The test, performed in the evening of July 17, 1991, was a major success. Based on a neglible pressure drop indicated on the pressure gages (1/4 psi), the vessel appeared to be structurally sound throughout the duration of the test (approx. 1.5 hrs.). No pressure increases were observed on the indicators looking at the beam tube bellows volumes. There was no indication of bubbles form the soap test on the welds and most of the fittings that were checked. There were some slight deviations in the actual procedure used. The UO filter was removed after the vessel had bled down to about 18 psig in order to speed up that aspect of the test. The rationale was that the higher velocity gas had already passed through at the higher pressures and there was no visible traces of the black uo particles. The rate of 4 psi/10 minutes seemed incredibly slow and often that time was reduced to just over half that rate. The testing personnel was allowed to stay in the pit throughout the duration of the test; this was a slight relaxation of the rules.

  3. Ambient noise interferes with auscultatory blood pressure measurement during exercise.

    PubMed

    Lightfoot, J T; Tuller, B; Williams, D F

    1996-04-01

    This study was designed to investigate whether the acoustical characteristics of the Korotkoff sounds (K-sounds) were altered during exercise and/or masked by the ambient noise. After signing informed consent, 11 subjects (8 females, 3 males; 27 +/- 2 yr; 166.2 +/- 3.2 cm; 62 +/- 5 kg; means +/- SD) underwent a cycle ergometer exercise test that increased in workload by 30 W every 3 min until volitional fatigue. Heart rate, auscultatory systolic (SBP) and diastolic blood pressure (DBP), and oxygen consumption were monitored 1 and 2 min into each work stage. The auscultatory K-sounds were recorded with a microphone mounted in a stethoscope tube for later frequency (Hz) and sound pressure level (dB SPL) analysis. Frequency and SPL of ambient noise (99 +/- 13 Hz and 64 +/- 1 db at maximum, respectively) increased during the exercise test to magnitudes similar to the SBP and DBP K-sounds (166 Hz, 66 db; and 128 Hz, 69 db, respectively). Additionally, the ambient noise was responsible for a significant damping of the frequency and SPL of the measured blood pressure K-sounds and a rise in the measured frequency of the SBP K-sounds. Furthermore, we observed "inaudible" K-sounds at lower frequencies than adjoining audible K-sounds (100 Hz vs 126 Hz), supporting the known underestimation of SBP by auscultation. The increase in ambient noise during exercise testing dampens and may mask the auscultatory K-sounds, thus making detection of the proper K-sounds during exercise difficult at best. Furthermore, the presence of inaudible K-sounds may further explain the published discrepancies between auscultatory and intraarterial blood pressure measurements during exercise.

  4. Baseline meteorological soundings for parametric environmental investigations at Kennedy Space Center and Vandenberg Air Force Base

    NASA Technical Reports Server (NTRS)

    Susko, M.; Stephens, J. B.

    1976-01-01

    Meteorological soundings representative of the atmospheric environment at the Kennedy Space Center, Florida and Vandenberg Air Force Base, California, are presented. Synthetic meteorological soundings at Kennedy Space Center, including fall, spring, and a sea breeze, and at Vandenberg Air Force Base (sea breeze with low and high level inversion and stationary upper level troughs) are shown. Soundings of frontal passages are listed. The Titan launch soundings at Kennedy Space Center present a wide range of meteorological conditions, both seasonal and time of day variations. The meteorological data input of altitude, wind speed, wind direction, temperature, and pressure may be used as meteorological inputs for the NASA/MSFC Multilayer Diffusion Model or other models to obtain quantitative estimates of effluent concentrations associated with the potential emission of major combustion products in the lower atmosphere to simulate actual launches of space vehicles. The Titan launch soundings are also of value in terms of rocket effluent measurements for analysis purposes.

  5. Sound source localization inspired by the ears of the Ormia ochracea

    NASA Astrophysics Data System (ADS)

    Kuntzman, Michael L.; Hall, Neal A.

    2014-07-01

    The parasitoid fly Ormia ochracea has the remarkable ability to locate crickets using audible sound. This ability is, in fact, remarkable as the fly's hearing mechanism spans only 1.5 mm which is 50× smaller than the wavelength of sound emitted by the cricket. The hearing mechanism is, for all practical purposes, a point in space with no significant interaural time or level differences to draw from. It has been discovered that evolution has empowered the fly with a hearing mechanism that utilizes multiple vibration modes to amplify interaural time and level differences. Here, we present a fully integrated, man-made mimic of the Ormia's hearing mechanism capable of replicating the remarkable sound localization ability of the special fly. A silicon-micromachined prototype is presented which uses multiple piezoelectric sensing ports to simultaneously transduce two orthogonal vibration modes of the sensing structure, thereby enabling simultaneous measurement of sound pressure and pressure gradient.

  6. Numerical model for the weakly nonlinear propagation of sound through turbulence

    NASA Technical Reports Server (NTRS)

    Lipkens, Bart; Blanc-Benon, Philippe

    1994-01-01

    When finite amplitude (or intense) sound, such as a sonic boom, propagates through a turbulent atmosphere, the propagation is strongly affected by the turbulence. The interaction between sound and turbulence has mostly been studied as a linear phenomenon, i.e., the nonlinear behavior of the intense sound has been neglected. It has been shown that turbulence has an effect on the perceived loudness of sonic booms, mainly by changing its peak pressure and rise time. Peak pressure and rise time are important factors that determine the loudness of the sonic boom when heard outdoors. However, the interaction between turbulence and nonlinear effects has mostly not been included in propagation studies of sonic booms. It is therefore important to investigate the influence of acoustical nonlinearity on the interaction of intense sound with turbulence.

  7. Sound velocity of tantalum under shock compression in the 18–142 GPa range

    SciTech Connect

    Xi, Feng Jin, Ke; Cai, Lingcang Geng, Huayun; Tan, Ye; Li, Jun

    2015-05-14

    Dynamic compression experiments of tantalum (Ta) within a shock pressure range from 18–142 GPa were conducted driven by explosive, a two-stage light gas gun, and a powder gun, respectively. The time-resolved Ta/LiF (lithium fluoride) interface velocity profiles were recorded with a displacement interferometer system for any reflector. Sound velocities of Ta were obtained from the peak state time duration measurements with the step-sample technique and the direct-reverse impact technique. The uncertainty of measured sound velocities were analyzed carefully, which suggests that the symmetrical impact method with step-samples is more accurate for sound velocity measurement, and the most important parameter in this type experiment is the accurate sample/window particle velocity profile, especially the accurate peak state time duration. From these carefully analyzed sound velocity data, no evidence of a phase transition was found up to the shock melting pressure of Ta.

  8. Rocket ozone sounding network data

    NASA Technical Reports Server (NTRS)

    Wright, D. U.; Krueger, A. J.; Foster, G. M.

    1978-01-01

    During the period December 1976 through February 1977, three regular monthly ozone profiles were measured at Wallops Flight Center, two special soundings were taken at Antigua, West Indies, and at the Churchill Research Range, monthly activities were initiated to establish stratospheric ozone climatology. This report presents the data results and flight profiles for the period covered.

  9. Demonstrating Sound Impulses in Pipes.

    ERIC Educational Resources Information Center

    Raymer, M. G.; Micklavzina, Stan

    1995-01-01

    Describes a simple, direct method to demonstrate the effects of the boundary conditions on sound impulse reflections in pipes. A graphical display of the results can be made using a pipe, cork, small hammer, microphone, and fast recording electronics. Explains the principles involved. (LZ)

  10. Sound, Noise, and Vibration Control.

    ERIC Educational Resources Information Center

    Yerges, Lyle F.

    This working guide on the principles and techniques of controlling acoustical environment is discussed in the light of human, environmental and building needs. The nature of sound and its variables are defined. The acoustical environment and its many materials, spaces and functional requirements are described, with specific methods for planning,…

  11. Review of Sound Card Photogates

    ERIC Educational Resources Information Center

    Gingl, Zoltan; Mingesz, Robert; Makra, Peter; Mellar, Janos

    2011-01-01

    Photogates are probably the most commonly used electronic instruments to aid experiments in the field of mechanics. Although they are offered by many manufacturers, they can be too expensive to be widely used in all classrooms, in multiple experiments or even at home experimentation. Today all computers have a sound card--an interface for analogue…

  12. Sound Stories for General Music

    ERIC Educational Resources Information Center

    Cardany, Audrey Berger

    2013-01-01

    Language and music literacy share a similar process of understanding that progresses from sensory experience to symbolic representation. The author identifies Bruner’s modes of understanding as they relate to using narrative in the music classroom to enhance music reading at iconic and symbolic levels. Two sound stories are included for…

  13. Sound Naming in Neurodegenerative Disease

    ERIC Educational Resources Information Center

    Chow, Maggie L.; Brambati, Simona M.; Gorno-Tempini, Maria Luisa; Miller, Bruce L.; Johnson, Julene K.

    2010-01-01

    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…

  14. Newborn Infants Orient to Sounds.

    ERIC Educational Resources Information Center

    Muir, Darwin; Field, Jeffrey

    1979-01-01

    In two experiments, the majority of 21 newborn infants who were maintained in an alert state consistently turned their heads toward a continuous sound source presented 90 degrees from midline. For most infants, this orientation response was rather slow, taking median latencies of 2.5 seconds to begin and 5.5 seconds to end. (JMB)

  15. Uncovering Spatial Variation in Acoustic Environments Using Sound Mapping

    PubMed Central

    Job, Jacob R.; Myers, Kyle; Naghshineh, Koorosh; Gill, Sharon A.

    2016-01-01

    Animals select and use habitats based on environmental features relevant to their ecology and behavior. For animals that use acoustic communication, the sound environment itself may be a critical feature, yet acoustic characteristics are not commonly measured when describing habitats and as a result, how habitats vary acoustically over space and time is poorly known. Such considerations are timely, given worldwide increases in anthropogenic noise combined with rapidly accumulating evidence that noise hampers the ability of animals to detect and interpret natural sounds. Here, we used microphone arrays to record the sound environment in three terrestrial habitats (forest, prairie, and urban) under ambient conditions and during experimental noise introductions. We mapped sound pressure levels (SPLs) over spatial scales relevant to diverse taxa to explore spatial variation in acoustic habitats and to evaluate the number of microphones needed within arrays to capture this variation under both ambient and noisy conditions. Even at small spatial scales and over relatively short time spans, SPLs varied considerably, especially in forest and urban habitats, suggesting that quantifying and mapping acoustic features could improve habitat descriptions. Subset maps based on input from 4, 8, 12 and 16 microphones differed slightly (< 2 dBA/pixel) from those based on full arrays of 24 microphones under ambient conditions across habitats. Map differences were more pronounced with noise introductions, particularly in forests; maps made from only 4-microphones differed more (> 4 dBA/pixel) from full maps than the remaining subset maps, but maps with input from eight microphones resulted in smaller differences. Thus, acoustic environments varied over small spatial scales and variation could be mapped with input from 4–8 microphones. Mapping sound in different environments will improve understanding of acoustic environments and allow us to explore the influence of spatial variation

  16. Geometric Constraints on Human Speech Sound Inventories.

    PubMed

    Dunbar, Ewan; Dupoux, Emmanuel

    2016-01-01

    We investigate the idea that the languages of the world have developed coherent sound systems in which having one sound increases or decreases the chances of having certain other sounds, depending on shared properties of those sounds. We investigate the geometries of sound systems that are defined by the inherent properties of sounds. We document three typological tendencies in sound system geometries: economy, a tendency for the differences between sounds in a system to be definable on a relatively small number of independent dimensions; local symmetry, a tendency for sound systems to have relatively large numbers of pairs of sounds that differ only on one dimension; and global symmetry, a tendency for sound systems to be relatively balanced. The finding of economy corroborates previous results; the two symmetry properties have not been previously documented. We also investigate the relation between the typology of inventory geometries and the typology of individual sounds, showing that the frequency distribution with which individual sounds occur across languages works in favor of both local and global symmetry.

  17. Calibration of sound velocimeter in pure water

    NASA Astrophysics Data System (ADS)

    Li, Zhiwei; Zhang, Baofeng; Li, Tao; Zhu, Junchao; Xie, Ziming

    2016-01-01

    Accurate measurement of sound speed is important to calibrate a sound velocity profiler which provides real-time sound velocity to the sonar equipment in oceanographic survey. The sound velocity profiler calculates the sound speed by measuring the time-of-flight of a 1 MHz single acoustic pulse to travel over about 300 mm path. A standard sound velocimeter instrument was invited to calibrate the sound velocity profiler in pure water at temperatures of 278,283, 288, 293, 298, 303 and 308K in a thermostatic vessel at one atmosphere. The sound velocity profiler was deployed in the thermostatic vessel alongside the standard sound velocimeter instrument and two platinum resistance thermometers (PRT) which were calibrated to 0.002k by comparison with a standard PRT. Time of flight circuit board was used to measure the time-of-flight to 22 picosecond precision. The sound speed which was measured by the sound velocity profiler was compared to the standard sound speed calculated by UNESCO to give the laboratory calibration coefficients and was demonstrated agreement with CTD-derived sound speed using Del Grosso's seawater equation after removing a bias.

  18. Geometric Constraints on Human Speech Sound Inventories

    PubMed Central

    Dunbar, Ewan; Dupoux, Emmanuel

    2016-01-01

    We investigate the idea that the languages of the world have developed coherent sound systems in which having one sound increases or decreases the chances of having certain other sounds, depending on shared properties of those sounds. We investigate the geometries of sound systems that are defined by the inherent properties of sounds. We document three typological tendencies in sound system geometries: economy, a tendency for the differences between sounds in a system to be definable on a relatively small number of independent dimensions; local symmetry, a tendency for sound systems to have relatively large numbers of pairs of sounds that differ only on one dimension; and global symmetry, a tendency for sound systems to be relatively balanced. The finding of economy corroborates previous results; the two symmetry properties have not been previously documented. We also investigate the relation between the typology of inventory geometries and the typology of individual sounds, showing that the frequency distribution with which individual sounds occur across languages works in favor of both local and global symmetry. PMID:27462296

  19. Peer Pressure

    MedlinePlus

    ... Surgery? A Week of Healthy Breakfasts Shyness Peer Pressure KidsHealth > For Teens > Peer Pressure A A A ... for the school play. previous continue When the Pressure's On Sometimes, though, the stresses in your life ...

  20. Blood pressure

    MedlinePlus Videos and Cool Tools

    Normal blood pressure is important for proper blood flow to the body's organs and tissues. The force of the blood on the walls of the arteries is called blood pressure. Blood pressure is measured both as the heart ...

  1. Phase encoding in the Mauthner system: implications in left-right sound source discrimination

    PubMed Central

    Weiss, Shennan A.; Preuss, Thomas; Faber, Donald S.

    2009-01-01

    The paired Teleost Mauthner (M-) cells and their associated network serve as an excellent system to study the biophysical basis of decision making. In teleosts, an abrupt sound evokes a M-spike, triggering a C-start escape that is usually directed away from a sound source. The response latency is minimized by electrical synapses between auditory afferents and the M-cell lateral dendrite. Here, we demonstrate that the electrical synapses also mediate phase encoding. Ramped sound pressure waves (150-250 Hz) evoked electrotonic postsynaptic potentials in the M-cell locked to two diametrically opposed phase angles that were frequency dependent but intensity independent. Phase encoding was also evident at the behavioral level underwater, as the stimuli evoked directional C-starts with an onset that was phase locked to the sound wave. In interneurons inhibitory to the M-cell these same stimuli also evoked phase locked electrotonic postsynaptic potentials and action potentials. The resulting chemical and electrical, i.e field effect, inhibitions functioned tonically and phasically respectively. Phase encoding could be important in underwater sound source localization, which is thought to require a neural computation involving a phase comparison between the pressure and the directional particle motion components of sound. This computation may be implemented by an inter-play between phase dependent afferent excitation and feedforward inhibition that activates the appropriate M-cell and directs the C-start away from the sound source. PMID:19295149

  2. Sound shielding by a piezoelectric membrane and a negative capacitor with feedback control.

    PubMed

    Sluka, Tomás; Kodama, Hidekazu; Fukada, Eiichi; Mokrý, Pavel

    2008-08-01

    The design and realization of an adaptive sound-shielding system based on a method to control the effective elastic stiffness of piezoelectric materials are presented in this paper. In this system, the sound-shielding effect is achieved by a sound reflection from the piezoelectric curved membrane fixed in rigid frame and connected to an active analog circuit that behaves as a negative capacitor. The acoustic transmission loss through the curved membrane was measured for the incident sound of frequency 1.6 kHz and of acoustic pressure level 80 dB. When the negative capacitor in the system was properly adjusted, the acoustic pressure level of the transmitted sound was reduced from the initial 60 dB to 15 dB by the action of the negative capacitor. Then the system was exposed to naturally changing operational conditions, and their effect on sound-shielding efficiency was studied. It is shown that the acoustic transmission loss of the system dropped by 35 dB within 30 min from the moment of negative capacitor adjustment. Therefore, a self-adjustment of the system has been implemented by appending an additional digital control circuit to the negative capacitor. It is shown that the aforementioned deteriorating effect has been eliminated by the adjusting action of the control circuit. The long-time sustainable value of 60 dB in the acoustic transmission loss of the adaptive sound shielding system has been achieved.

  3. Computational fluid dynamics simulation of sound propagation through a blade row.

    PubMed

    Zhao, Lei; Qiao, Weiyang; Ji, Liang

    2012-10-01

    The propagation of sound waves through a blade row is investigated numerically. A wave splitting method in a two-dimensional duct with arbitrary mean flow is presented, based on which pressure amplitude of different wave mode can be extracted at an axial plane. The propagation of sound wave through a flat plate blade row has been simulated by solving the unsteady Reynolds average Navier-Stokes equations (URANS). The transmission and reflection coefficients obtained by Computational Fluid Dynamics (CFD) are compared with semi-analytical results. It indicates that the low order URANS scheme will cause large errors if the sound pressure level is lower than -100 dB (with as reference pressure the product of density, main flow velocity, and speed of sound). The CFD code has sufficient precision when solving the interaction of sound wave and blade row providing the boundary reflections have no substantial influence. Finally, the effects of flow Mach number, blade thickness, and blade turning angle on sound propagation are studied.

  4. 7 CFR 29.3056 - Sound.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Sound. 29.3056 Section 29.3056 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Sound. Free of damage....

  5. 7 CFR 29.3056 - Sound.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Sound. 29.3056 Section 29.3056 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Sound. Free of damage....

  6. 7 CFR 29.3056 - Sound.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Sound. 29.3056 Section 29.3056 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Sound. Free of damage....

  7. Dredged Material Management in Long Island Sound

    EPA Pesticide Factsheets

    Information on Western and Central Long Island Sound Dredged Material Disposal Sites including the Dredged Material Management Plan and Regional Dredging Team. Information regarding the Eastern Long Island Sound Selected Site including public meetings.

  8. A study of sound absorption by street canyon boundaries and asphalt rubber concrete pavement

    NASA Astrophysics Data System (ADS)

    Drysdale, Graeme Robert

    A sound field model, based on a classical diffusion equation, is extended to account for sound absorption in a diffusion parameter used to model sound energy in a narrow street canyon. The model accounts for a single sound absorption coefficient, separate accommodation coefficients and a combination of separate absorption and accommodation coefficients from parallel canyon walls. The new expressions are compared to the original formula through numerical simulations to reveal the effect of absorption on sound diffusion. The newly established analytical formulae demonstrate satisfactory agreement with their predecessor under perfect reflection. As well, the influence of the extended diffusion parameter on normalized sound pressure levels in a narrow street canyon is in agreement with experimental data. The diffusion parameters are used to model sound energy density in a street canyon as a function of the sound absorption coefficient of the street canyon walls. The acoustic and material properties of conventional and asphalt rubber concrete (ARC) pavement are also studied to assess how the crumb rubber content influences sound absorption in street canyons. The porosity and absolute permeability of compacted specimens of asphalt rubber concrete are measured and compared to their normal and random incidence sound absorption coefficients as a function of crumb rubber content in the modified binder. Nonlinear trends are found between the sound absorption coefficients, porosity and absolute permeability of the compacted specimens and the percentage of crumb rubber in the modified binders. The cross-sectional areas of the air voids on the surfaces of the compacted specimens are measured using digital image processing techniques and a linear relationship is obtained between the average void area and crumb rubber content. The measured material properties are used to construct an empirical formula relating the average porosity, normal incidence noise reduction coefficients and

  9. Dispersion of Sound in Marine Sediments

    DTIC Science & Technology

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Dispersion of Sound in Marine Sediments N. Ross...our understanding of the interaction of sound with the ocean bottom is the frequency dependence of sound speed and attenuation in marine sediments...The long term goals of this research project are related to the investigation of dispersion of sound speed and attenuation at low frequencies (< 2

  10. Sound quality indicators for urban places in Paris cross-validated by Milan data.

    PubMed

    Ricciardi, Paola; Delaitre, Pauline; Lavandier, Catherine; Torchia, Francesca; Aumond, Pierre

    2015-10-01

    A specific smartphone application was developed to collect perceptive and acoustic data in Paris. About 3400 questionnaires were analyzed, regarding the global sound environment characterization, the perceived loudness of some emergent sources and the presence time ratio of sources that do not emerge from the background. Sound pressure level was recorded each second from the mobile phone's microphone during a 10-min period. The aim of this study is to propose indicators of urban sound quality based on linear regressions with perceptive variables. A cross validation of the quality models extracted from Paris data was carried out by conducting the same survey in Milan. The proposed sound quality general model is correlated with the real perceived sound quality (72%). Another model without visual amenity and familiarity is 58% correlated with perceived sound quality. In order to improve the sound quality indicator, a site classification was performed by Kohonen's Artificial Neural Network algorithm, and seven specific class models were developed. These specific models attribute more importance on source events and are slightly closer to the individual data than the global model. In general, the Parisian models underestimate the sound quality of Milan environments assessed by Italian people.

  11. Proper orthogonal decomposition and cluster weighted modeling for sensitivity analysis of sound propagation in the atmospheric surface layer.

    PubMed

    Pettit, Chris L; Wilson, D Keith

    2007-09-01

    Outdoor sound propagation predictions are compromised by uncertainty and error in the atmosphere and terrain representations, and sometimes also by simplified or incorrect physics. A model's predictive power, i.e., its accurate representation of the sound propagation, cannot be assessed without first quantifying the ensemble sound pressure variability and sensitivity to uncertainties in the model's governing parameters. This paper describes fundamental steps toward this goal for a single-frequency point source. The atmospheric surface layer is represented through Monin-Obukhov similarity theory and the acoustic ground properties with a relaxation model. Sound propagation is predicted with the parabolic equation method. Governing parameters are modeled as independent random variables across physically reasonable ranges. Latin hypercube sampling and proper orthogonal decomposition (POD) are employed in conjunction with cluster-weighted models to develop compact representations of the sound pressure random field. Full-field sensitivity of the sound pressure field is computed via the sensitivities of the POD mode coefficients to the system parameters. Ensemble statistics of the full-field sensitivities are computed to illustrate their relative importance at every down range location. The central role of sensitivity analysis in uncertainty quantification of outdoor sound propagation is discussed and pitfalls of sampling-based sensitivity analysis for outdoor sound propagation are described.

  12. Aerodynamic sound of flow past an airfoil

    NASA Technical Reports Server (NTRS)

    Wang, Meng

    1995-01-01

    Reynolds number of 104. The far-field noise is computed using Curle's extension to the Lighthill analogy (Curle 1955). An effective method for separating the physical noise source from spurious boundary contributions is developed. This allows an accurate evaluation of the Reynolds stress volume quadrupoles, in addition to the more readily computable surface dipoles due to the unsteady lift and drag. The effect of noncompact source distribution on the far-field sound is assessed using an efficient integration scheme for the Curle integral, with full account of retarded-time variations. The numerical results confirm in quantitative terms that the far-field sound is dominated by the surface pressure dipoles at low Mach number. The techniques developed are applicable to a wide range of flows, including jets and mixing layers, where the Reynolds stress quadrupoles play a prominent or even dominant role in the overall sound generation.

  13. MegaSound: Sound in Irish megalithic buildings

    NASA Astrophysics Data System (ADS)

    Reijs, Victor

    2002-11-01

    Stimulated by the studies done by Paul Deveraux and Robert Jahn, research has been conducted on the sound properties of two megalithic chambers is Ireland: Dowth South and Fourknocks I. As reference measurements two normal rooms (bed- and bathroom) have been studied. The following aspects will be covered in the presentation: some theoretical background on acoustical modes (within a passage, a chamber, and a combination of them: Helmholtz resonator); tips for doing sound experiments inside megalithic chambers (like: equipment, measurement software, power provisioning and calibrating); frequency response measurements (between 20 and 200 Hz) for the surveyed chambers/rooms; comparison of the results with other researchers' results; background on the pitch of the human (male, female, and child) voices in neolithic times and recommendations for future research. The presentation also provides insight in the aeralization (simulation) of sound in a megalithic chamber, covering: software that can do these simulations; issues in finding the basic information, e.g., acoustic absorption coefficients and provide examples of the results. I would like to thank all the people who have provided constructive feedback on my work (http://www.iol.ie/approxgeniet/eng/megasound.htm).

  14. Unified modeling of turbulence effects on sound propagation.

    PubMed

    Cheinet, Sylvain; Ehrhardt, Loic; Juvé, Daniel; Blanc-Benon, Philippe

    2012-10-01

    Many aspects of outdoor sound propagation depend on the scattering effects induced by atmospheric turbulence. Standard analytical and numerical assessments of these effects make an a priori distinction between the scattering effects at large versus small angles. The present study evaluates the ability of a numerical model in overcoming this distinction. The model solves a set of two coupled equations for the sound pressure and vector acoustic velocity, with the finite-difference time domain approach. It is first introduced and evaluated. The numerical predictions are compared to well-known analytical solutions in the case of two-dimensional plane wave propagation through turbulence. They are found to agree in the investigated scenarios. Hence, the finite-difference, time domain solution of the two coupled equations provides a unified, versatile numerical approach to investigating the effects of atmospheric turbulence on sound propagation. The comparison also provides original insights on the applicability and limitations of various methods used to investigate sound propagation through turbulence.

  15. Evaluation of sound field systems in elementary school classrooms

    NASA Astrophysics Data System (ADS)

    Vigeant, Michelle C.; Kruger, Kelly

    2003-10-01

    Our primary purpose in this study was to determine the relevant ergonomic issues associated with daily use of sound field systems in elementary school classrooms, in order to develop a purchasing guideline and technical specification. The secondary purpose was to evaluate these systems to identify if one or more acoustical parameters could be used to determine the quality and effectiveness of a system. Six sound field systems, with varying numbers and types of speakers, were chosen as a cross-section of available systems on the market. Six representative classrooms, currently in use, were selected based on a range of reverberation times and background noise levels. All systems were installed for two weeks in each classroom. Student speech intelligibility (SI) tests using phonetically balanced word lists were conducted, as well as teacher interviews. The acoustical parameters measured were clarity ratios C50 and C80, speech transmission indices STI and R(rapid)STI, sound pressure level (SPL) uniformity and frequency response. An improvement in SI was found for all systems. Only SPL uniformity and frequency response were found to be useful distinguishing performance parameters between systems. Ergonomic design aspects of sound field systems had a significant influence on the acceptance and usage in the classroom.

  16. New acoustical technology of sound absorption based on reverse horn

    NASA Astrophysics Data System (ADS)

    Zhang, Yong Yan; Wu, Jiu Hui; Cao, Song Hua; Cao, Pei; Zhao, Zi Ting

    2016-12-01

    In this paper, a novel reverse horn’s sound-absorption mechanism and acoustic energy focusing mechanism for low-frequency broadband are presented. Due to the alternation of the reverse horn’s thickness, the amplitude of the acoustic pressure propagated in the structure changes, which results in growing energy focused in the edge and in the reverse horn’s tip when the characteristic length is equal to or less than a wavelength and the incident wave is compressed. There are two kinds of methods adopted to realize energy dissipation. On the one hand, sound-absorbing materials are added in incident direction in order to overcome the badness of the reverse horn’s absorption in high frequency and improve the overall high-frequency and low-frequency sound-absorption coefficients; on the other hand, adding mass and film in its tip could result in mechanical energy converting into heat energy due to the coupled vibration of mass and the film. Thus, the reverse horn with film in the tip could realize better sound absorption for low-frequency broadband. These excellent properties could have potential applications in the one-dimensional absorption wedge and for the control of acoustic wave.

  17. Impact of low-frequency sound on historic structures

    NASA Astrophysics Data System (ADS)

    Sutherland, Louis C.; Horonjeff, Richard D.

    2005-09-01

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

  18. Visualization of Heart Sounds and Motion Using Multichannel Sensor

    NASA Astrophysics Data System (ADS)

    Nogata, Fumio; Yokota, Yasunari; Kawamura, Yoko

    2010-06-01

    As there are various difficulties associated with auscultation techniques, we have devised a technique for visualizing heart motion in order to assist in the understanding of heartbeat for both doctors and patients. Auscultatory sounds were first visualized using FFT and Wavelet analysis to visualize heart sounds. Next, to show global and simultaneous heart motions, a new technique for visualization was established. The visualization system consists of a 64-channel unit (63 acceleration sensors and one ECG sensor) and a signal/image analysis unit. The acceleration sensors were arranged in a square array (8×8) with a 20-mm pitch interval, which was adhered to the chest surface. The heart motion of one cycle was visualized at a sampling frequency of 3 kHz and quantization of 12 bits. The visualized results showed a typical waveform motion of the strong pressure shock due to closing tricuspid valve and mitral valve of the cardiac apex (first sound), and the closing aortic and pulmonic valve (second sound) in sequence. To overcome difficulties in auscultation, the system can be applied to the detection of heart disease and to the digital database management of the auscultation examination in medical areas.

  19. BOREAS AFM-03-NCAR Electra 1994 Aircraft Sounding Data

    NASA Technical Reports Server (NTRS)

    Lenschow, Donald H.; Oncley, Steven P.; Hall, Forrest G. (Editor); Knapp, David E. (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The Boreal Ecosystem-Atmosphere Study (BOREAS) Airborne Fluxes and Meteorology (AFM)-3 team used the National Center for Atmospheric Research's (NCAR) Electra aircraft to make sounding measurements to study the planetary boundary layer using in situ and remote-sensing measurements. Measurements were made of wind speed and direction, air pressure and temperature, potential temperature, dewpoint, mixing ratio of H, O, CO, concentration, and ozone concentration. Twenty-five research missions were flown over the Northern Study Area (NSA), Southern Study Area (SSA), and the transect during BOREAS Intensive Field Campaigns (IFCs) 1, 2, and 3 during 1994. All missions had from four to ten soundings through the top of the planetary boundary layer. This sounding data set contains all of the in situ vertical profiles through the boundary layer top that were made (with the exception of 'porpoise' maneuvers). Data were recorded in one-second time intervals. These data are stored in tabular ASCII files. The NCAR Electra 1994 aircraft sounding data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

  20. Sound absorption by subwavelength membrane structures: A geometric perspective

    NASA Astrophysics Data System (ADS)

    Yang, Min; Li, Yong; Meng, Chong; Fu, Caixing; Mei, Jun; Yang, Zhiyu; Sheng, Ping

    2015-12-01

    Decorated membranes comprising a thin layer of elastic film with small rigid platelets fixed on top have been found to be efficient absorbers of low-frequency sound. In this work we consider the problem of sound absorption from a perspective aimed at deriving upper bounds under different scenarios, i.e., whether the sound is incident from one side only or from both sides, and whether there is a reflecting surface on the back side of the membrane. By considering the negligible thickness of the membrane, usually on the order of a fraction of one millimeter, we derive a relation showing that the sum of the incoming sound waves' (complex) pressure amplitudes, averaged over the area of the membrane, must be equal to that of the outgoing waves. By using this relation, and without going to any details of the wave solutions, it is shown that the maximum absorption achievable from one-sided incidence is 50%, while the maximum absorption with a back-reflecting surface can reach 100%. The latter was attained by the hybridized resonances. All the results are shown to be in excellent agreement with the experiments. This generalized perspective, when used together with the Green function's formalism, can be useful in gaining insights into the constraints on what are achievable in scatterings and absorption by thin film structures and delineating them.

  1. Sound localization by echolocating bats

    NASA Astrophysics Data System (ADS)

    Aytekin, Murat

    Echolocating bats emit ultrasonic vocalizations and listen to echoes reflected back from objects in the path of the sound beam to build a spatial representation of their surroundings. Important to understanding the representation of space through echolocation are detailed studies of the cues used for localization, the sonar emission patterns and how this information is assembled. This thesis includes three studies, one on the directional properties of the sonar receiver, one on the directional properties of the sonar transmitter, and a model that demonstrates the role of action in building a representation of auditory space. The general importance of this work to a broader understanding of spatial localization is discussed. Investigations of the directional properties of the sonar receiver reveal that interaural level difference and monaural spectral notch cues are both dependent on sound source azimuth and elevation. This redundancy allows flexibility that an echolocating bat may need when coping with complex computational demands for sound localization. Using a novel method to measure bat sonar emission patterns from freely behaving bats, I show that the sonar beam shape varies between vocalizations. Consequently, the auditory system of a bat may need to adapt its computations to accurately localize objects using changing acoustic inputs. Extra-auditory signals that carry information about pinna position and beam shape are required for auditory localization of sound sources. The auditory system must learn associations between extra-auditory signals and acoustic spatial cues. Furthermore, the auditory system must adapt to changes in acoustic input that occur with changes in pinna position and vocalization parameters. These demands on the nervous system suggest that sound localization is achieved through the interaction of behavioral control and acoustic inputs. A sensorimotor model demonstrates how an organism can learn space through auditory-motor contingencies

  2. Newborns' Head Orientation toward Sounds Within Hemifields.

    ERIC Educational Resources Information Center

    Fenwick, Kimberley; And Others

    This experiment examined the accuracy with which newborn infants orient their heads toward a sound positioned off midline within hemifields. The study also evaluated newborns' ability to update the angle of their head turn to match a change in localization of an ongoing sound. Alert newborns were held in a supine position and presented a sound at…

  3. Bubbles That Change the Speed of Sound

    ERIC Educational Resources Information Center

    Planinsic, Gorazd; Etkina, Eugenia

    2012-01-01

    The influence of bubbles on sound has long attracted the attention of physicists. In his 1920 book Sir William Bragg described sound absorption caused by foam in a glass of beer tapped by a spoon. Frank S. Crawford described and analyzed the change in the pitch of sound in a similar experiment and named the phenomenon the "hot chocolate effect."…

  4. Third Sound Amplification and Detailed Balance

    SciTech Connect

    Eddinger, J. D.; Ellis, F. M.

    2006-09-07

    Condensation of atoms from the vapor into a third sound resonance is expected to be capable of acoustic amplification. This results from normal to superfluid conversion that coherently accommodates atoms into the third sound velocity field. Consideration of third sound in light of the equilibrium detailed balance between vapor particles and the superfluid film provides further evidence that acoustic amplification is attainable.

  5. Auditory Icons: Using Sound in Computer Interfaces.

    ERIC Educational Resources Information Center

    Gaver, W. W.

    1987-01-01

    An appoach to the use of sound in computer interfaces, proposed in this article, emphasizes the role of sound in conveying information about the world to the listener. This approach argues that auditory icons, i.e., caricatures of naturally occurring sounds, provide a natural way to represent dimensional data as well as conceptual objects in a…

  6. 75 FR 76079 - Sound Incentive Compensation Guidance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-07

    ... Office of Thrift Supervision Sound Incentive Compensation Guidance AGENCY: Office of Thrift Supervision... collection. Title of Proposal: Sound Incentive Compensation Guidance. OMB Number: 1550-0129. Form Number: N/A... principles and the guidance are consistent with the Principles for Sound Compensation Practices adopted...

  7. 75 FR 22679 - Sound Incentive Compensation Guidance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-29

    ... Office of Thrift Supervision Sound Incentive Compensation Guidance AGENCY: Office of Thrift Supervision... collection. Title of Proposal: Sound Incentive Compensation Guidance. OMB Number: 1550-0NEW. Form Number: N/A... principles and the guidance are consistent with the Principles for Sound Compensation Practices adopted...

  8. 47 CFR 74.603 - Sound channels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Sound channels. 74.603 Section 74.603... Stations § 74.603 Sound channels. (a) The frequencies listed in § 74.602(a) may be used for the simultaneous transmission of the picture and sound portions of TV broadcast programs and for cue and...

  9. 47 CFR 74.603 - Sound channels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Sound channels. 74.603 Section 74.603... Stations § 74.603 Sound channels. (a) The frequencies listed in § 74.602(a) may be used for the simultaneous transmission of the picture and sound portions of TV broadcast programs and for cue and...

  10. A Lexical Analysis of Environmental Sound Categories

    ERIC Educational Resources Information Center

    Houix, Olivier; Lemaitre, Guillaume; Misdariis, Nicolas; Susini, Patrick; Urdapilleta, Isabel

    2012-01-01

    In this article we report on listener categorization of meaningful environmental sounds. A starting point for this study was the phenomenological taxonomy proposed by Gaver (1993b). In the first experimental study, 15 participants classified 60 environmental sounds and indicated the properties shared by the sounds in each class. In a second…

  11. 47 CFR 74.603 - Sound channels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Sound channels. 74.603 Section 74.603... Stations § 74.603 Sound channels. (a) The frequencies listed in § 74.602(a) may be used for the simultaneous transmission of the picture and sound portions of TV broadcast programs and for cue and...

  12. 47 CFR 74.603 - Sound channels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Sound channels. 74.603 Section 74.603... Stations § 74.603 Sound channels. (a) The frequencies listed in § 74.602(a) may be used for the simultaneous transmission of the picture and sound portions of TV broadcast programs and for cue and...

  13. The Early Years: Becoming Attuned to Sound

    ERIC Educational Resources Information Center

    Ashbrook, Peggy

    2014-01-01

    Exploration of making and changing sounds is part of the first-grade performance expectation 1-PS4-1, "Plan and conduct investigations to provide evidence that vibrating materials can make sound and that sound can make materials vibrate" (NGSS Lead States 2013, p. 10; see Internet Resource). Early learning experiences build toward…

  14. 75 FR 53023 - Sound Incentive Compensation Guidance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-30

    ... Office of Thrift Supervision Sound Incentive Compensation Guidance AGENCY: Office of Thrift Supervision... collection. Title of Proposal: Sound Incentive Compensation Guidance. OMB Number: 1550-0129. Form Number: N/A... principles and the guidance are consistent with the Principles for Sound Compensation Practices adopted...

  15. 47 CFR 74.603 - Sound channels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Sound channels. 74.603 Section 74.603... Stations § 74.603 Sound channels. (a) The frequencies listed in § 74.602(a) may be used for the simultaneous transmission of the picture and sound portions of TV broadcast programs and for cue and...

  16. Sound-Symbolism Boosts Novel Word Learning

    ERIC Educational Resources Information Center

    Lockwood, Gwilym; Dingemanse, Mark; Hagoort, Peter

    2016-01-01

    The existence of sound-symbolism (or a non-arbitrary link between form and meaning) is well-attested. However, sound-symbolism has mostly been investigated with nonwords in forced choice tasks, neither of which are representative of natural language. This study uses ideophones, which are naturally occurring sound-symbolic words that depict sensory…

  17. The United States sounding rocket program

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The United States sounding rocket program is discussed. The program is concerned with the fields of solar physics, galactic astronomy, fields and particles, ionospheric physics, aeronomy, and meteorology. Sounding rockets are described with respect to propulsion systems, gross weight, and capabilities. Instruments used to conduct ionospheric probing missions are examined. Results of previously conducted sounding rocket missions are included.

  18. 33 CFR 167.1702 - In Prince William Sound: Prince William Sound Traffic Separation Scheme.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false In Prince William Sound: Prince William Sound Traffic Separation Scheme. 167.1702 Section 167.1702 Navigation and Navigable Waters COAST....1702 In Prince William Sound: Prince William Sound Traffic Separation Scheme. The Prince William...

  19. 33 CFR 167.1702 - In Prince William Sound: Prince William Sound Traffic Separation Scheme.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false In Prince William Sound: Prince William Sound Traffic Separation Scheme. 167.1702 Section 167.1702 Navigation and Navigable Waters COAST....1702 In Prince William Sound: Prince William Sound Traffic Separation Scheme. The Prince William...

  20. 33 CFR 167.1702 - In Prince William Sound: Prince William Sound Traffic Separation Scheme.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false In Prince William Sound: Prince William Sound Traffic Separation Scheme. 167.1702 Section 167.1702 Navigation and Navigable Waters COAST....1702 In Prince William Sound: Prince William Sound Traffic Separation Scheme. The Prince William...

  1. 33 CFR 167.1702 - In Prince William Sound: Prince William Sound Traffic Separation Scheme.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false In Prince William Sound: Prince William Sound Traffic Separation Scheme. 167.1702 Section 167.1702 Navigation and Navigable Waters COAST....1702 In Prince William Sound: Prince William Sound Traffic Separation Scheme. The Prince William...

  2. Listener Expertise and Sound Identification Influence the Categorization of Environmental Sounds

    ERIC Educational Resources Information Center

    Lemaitre, Guillaume; Houix, Olivier; Misdariis, Nicolas; Susini, Patrick

    2010-01-01

    The influence of listener's expertise and sound identification on the categorization of environmental sounds is reported in three studies. In Study 1, the causal uncertainty of 96 sounds was measured by counting the different causes described by 29 participants. In Study 2, 15 experts and 15 nonexperts classified a selection of 60 sounds and…

  3. 33 CFR 167.1702 - In Prince William Sound: Prince William Sound Traffic Separation Scheme.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false In Prince William Sound: Prince William Sound Traffic Separation Scheme. 167.1702 Section 167.1702 Navigation and Navigable Waters COAST....1702 In Prince William Sound: Prince William Sound Traffic Separation Scheme. The Prince William...

  4. Size and scale effects as constraints in insect sound communication

    PubMed Central

    Bennet-Clark, H. C.

    1998-01-01

    For optimal transfer of power to the surrounding medium, a sound source should have a radius of 1/6 to 1/4 of the sound wavelength. Sound-waves propagate from the source as compressions and rarefactions of the fluid medium, which decay by spreading and viscous losses. Higher frequencies are more easily refracted and reflected by objects in the environment, causing degradation of signal structure. In open air or water, the sound spreads spherically and decays by the inverse square law. If the sound is restricted to two dimensions rather than three, it decays as the inverse of range, whereas waves within a rod decay largely due to viscous losses; such calls are usually rather simple pulses and rely on the initial time of arrival because of multiple pathlengths or different propagation velocities in the environment. Because of the relationship between calling success and reproductive success, singing insects are under selective pressure to optimize the range, and to maintain the specificity, of their calls. Smaller insects have less muscle power; because of their small sound sources, higher frequencies will be radiated more efficiently than lower frequencies, but in order to produce brief loud pulses from a long-duration muscle contraction they may use both a frequency multiplier mechanism and a mechanical power amplifier. Airborne insect sounds in the range from 1 to 5 kHz tend to have sustained puretone components and a specific pattern of pulses which propagate accurately. Where the song frequency is higher, the pulses tend to become briefer, with a rapid initial build-up that gives a reliable time of onset through obstructed transmission pathways. These scale effects may be related both to the sound-producing mechanism and the auditory system of the receiver. Tiny insects have the special acoustic problem of communicating with only a small amount of available power. Some, such as fruit flies, communicate at low frequencies, at close range, by generating air

  5. Sediment transport in Norton Sound, Alaska

    USGS Publications Warehouse

    Drake, D.E.; Cacchione, D.A.; Muench, R.D.; Nelson, C.H.

    1980-01-01

    The Yukon River, the largest single source of Bering Sea sediment, delivers >95% of its sediment load at the southwest corner of Norton Sound during the ice-free months of late May through October. During this period, surface winds in the northern Bering Sea area are generally light from the south and southwest, and surface waves are not significant. Although wind stress may cause some transport of low-density turbid surface water into the head of Norton Sound, the most significant transport of Yukon River suspended matter occurs within advective currents flowing north across the outer part of the sound. The thickest accumulations of modern Yukon silt and very fine sand occur beneath this persistent current. We monitored temporal variations in bottom currents, pressure, and suspended-matter concentrations within this major transport pathway for 80 days in the summer of 1977 using a Geological Processes Bottom Environmental (GEOPROBE) tripod system. The record reveals two distinctive periods of bottom flow and sediment transport: an initial 59 days (July 8-September 5) of fair-weather conditions, characterized by tidally dominated currents and relatively low, stable suspended-matter concentrations; and a 21-day period (September 5-September 26) during which several storms traversed the northern Bering Sea, mean suspended-matter concentrations near the bottom increased by a factor of five, and the earlier tidal dominance was overshadowed by wind-driven and oscillatory wave-generated currents. Friction velocities (u*) at the GEOPROBE site were generally subcritical during the initial fair-weather period. In contrast, the 21-day stormy period was characterized by u* values that exceeded the critical level of 1.3 cm/s more than 60% of the time. The GEPROBE data suggest that the very fine sand constituting about 50% of the sediment on the outer part of the Yukon prodelta is transported during a few late-summer and fall storms each year. A conservative estimate shows that

  6. Effects of sound level fluctuations on annoyance caused by aircraft-flyover noise

    NASA Technical Reports Server (NTRS)

    Mccurdy, D. A.

    1979-01-01

    A laboratory experiment was conducted to determine the effects of variations in the rate and magnitude of sound level fluctuations on the annoyance caused by aircraft-flyover noise. The effects of tonal content, noise duration, and sound pressure level on annoyance were also studied. An aircraft-noise synthesis system was used to synthesize 32 aircraft-flyover noise stimuli representing the factorial combinations of 2 tone conditions, 2 noise durations, 2 sound pressure levels, 2 level fluctuation rates, and 2 level fluctuation magnitudes. Thirty-two test subjects made annoyance judgements on a total of 64 stimuli in a subjective listening test facility simulating an outdoor acoustic environment. Variations in the rate and magnitude of level fluctuations were found to have little, if any, effect on annoyance. Tonal content, noise duration, sound pressure level, and the interaction of tonal content with sound pressure level were found to affect the judged annoyance significantly. The addition of tone corrections and/or duration corrections significantly improved the annoyance prediction ability of noise rating scales.

  7. Design and implementation of an underwater sound recording device.

    PubMed

    Martinez, Jayson J; Myers, Josh R; Carlson, Thomas J; Deng, Z Daniel; Rohrer, John S; Caviggia, Kurt A; Woodley, Christa M; Weiland, Mark A

    2011-01-01

    To monitor the underwater sound and pressure waves generated by anthropogenic activities such as underwater blasting and pile driving, an autonomous system was designed to record underwater acoustic signals. The underwater sound recording device (USR) allows for connections of two hydrophones or other dynamic pressure sensors, filters high frequency noise out of the collected signals, has a gain that can be independently set for each sensor, and allows for 2 h of data collection. Two versions of the USR were created: a submersible model deployable to a maximum depth of 300 m, and a watertight but not fully submersible model. Tests were performed on the USR in the laboratory using a data acquisition system to send single-frequency sinusoidal voltages directly to each component. These tests verified that the device operates as designed and performs as well as larger commercially available data acquisition systems, which are not suited for field use. On average, the designed gain values differed from the actual measured gain values by about 0.35 dB. A prototype of the device was used in a case study to measure blast pressures while investigating the effect of underwater rock blasting on juvenile Chinook salmon and rainbow trout. In the case study, maximum positive pressure from the blast was found to be significantly correlated with frequency of injury for individual fish. The case study also demonstrated that the device withstood operation in harsh environments, making it a valuable tool for collecting field measurements.

  8. Design and Implementation of an Underwater Sound Recording Device

    PubMed Central

    Martinez, Jayson J.; Myers, Josh R.; Carlson, Thomas J.; Deng, Z. Daniel; Rohrer, John S.; Caviggia, Kurt A.; Woodley, Christa M.; Weiland, Mark A.

    2011-01-01

    To monitor the underwater sound and pressure waves generated by anthropogenic activities such as underwater blasting and pile driving, an autonomous system was designed to record underwater acoustic signals. The underwater sound recording device (USR) allows for connections of two hydrophones or other dynamic pressure sensors, filters high frequency noise out of the collected signals, has a gain that can be independently set for each sensor, and allows for 2 h of data collection. Two versions of the USR were created: a submersible model deployable to a maximum depth of 300 m, and a watertight but not fully submersible model. Tests were performed on the USR in the laboratory using a data acquisition system to send single-frequency sinusoidal voltages directly to each component. These tests verified that the device operates as designed and performs as well as larger commercially available data acquisition systems, which are not suited for field use. On average, the designed gain values differed from the actual measured gain values by about 0.35 dB. A prototype of the device was used in a case study to measure blast pressures while investigating the effect of underwater rock blasting on juvenile Chinook salmon and rainbow trout. In the case study, maximum positive pressure from the blast was found to be significantly correlated with frequency of injury for individual fish. The case study also demonstrated that the device withstood operation in harsh environments, making it a valuable tool for collecting field measurements. PMID:22164089

  9. Sounding rockets explore the ionosphere

    SciTech Connect

    Mendillo, M. )

    1990-08-01

    It is suggested that small, expendable, solid-fuel rockets used to explore ionospheric plasma can offer insight into all the processes and complexities common to space plasma. NASA's sounding rocket program for ionospheric research focuses on the flight of instruments to measure parameters governing the natural state of the ionosphere. Parameters include input functions, such as photons, particles, and composition of the neutral atmosphere; resultant structures, such as electron and ion densities, temperatures and drifts; and emerging signals such as photons and electric and magnetic fields. Systematic study of the aurora is also conducted by these rockets, allowing sampling at relatively high spatial and temporal rates as well as investigation of parameters, such as energetic particle fluxes, not accessible to ground based systems. Recent active experiments in the ionosphere are discussed, and future sounding rocket missions are cited.

  10. Mississippi Sound remote sensing study

    NASA Technical Reports Server (NTRS)

    Atwell, B. H.; Thomann, G. C.

    1972-01-01

    Remote sensing techniques are being developed to study near shore marine waters in the Mississippi Sound. Specific elements of the investigation include: (1) evaluation of existing techniques and instrument capabilities for remote measurement of parameters which characterize near shore water; (2) integration of these parameters into a system which will make possible the definition of circulation characteristics; (3) conduct of applications experiments; and (4) definition of hardware development requirements and/or system specifications. Efforts have emphasized: (1) development of a satisfactory system of gathering ground truth over the entire area of Mississippi Sound to aid in evaluating remotely sensed data; (2) conduct of two data acquisition experiments; (3) analysis of individual sensor data from completed flights; and (4) pursuit of methods which will allow interrelations between data from individual sensors in order to add another dimension to the study.

  11. Sound Localization in Multisource Environments

    DTIC Science & Technology

    2009-03-01

    Stimuli The auditory stimuli employed in this experiment were 50 phonetically balanced (PB) monosyllabic words drawn from a single list of the PB50 word...2kHz - 16kHz), and were level normalized. They were also processed with the Pitch Synchronous Overlap and Add (PSOLA) algorithm in PRAAT to change...see Figure 1). 3.2.3 Stimuli Environmental sounds (e.g., telephone, tire screech, applause, etc.) and speech tokens (50 words from the phonetically

  12. Speedy sound and cosmic structure.

    PubMed

    Magueijo, João

    2008-06-13

    If the speed of sound were vastly larger in the early Universe, a near scale-invariant spectrum of density fluctuations could have been produced even if the Universe did not submit to conventional solutions to the horizon problem. We examine how the mechanism works, presenting full mathematical solutions and their heuristics. We then discuss several concrete models based on scalar fields and hydrodynamical matter that realize this mechanism, but stress that the proposed mechanism is more fundamental and general.

  13. Category 5: Sound Generation In Viscous Problems. Problem 2: Sound Generation By Flow Over a Cavity

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda S.

    2004-01-01

    The discrete frequency sound produced by the flow of air at low subsonic speeds over a deep cavity was investigated. A long aspect ratio rectangular cavity with a leading edge overhang that cut off of the cavity opening was placed flush with the top surface of a wind tunnel. The approach flow velocity was maintained at 50 m/s for the benchmark problem although results are also presented for other conditions. Boundary layer measurements conducted with a single element hotwire anemometer indicated that the boundary layer thickness just upstream of the cavity was equal to 17 mm. Sound pressure level measurements were made at three locations in the cavity: the center of the leading edge wall, the center of the cavity floor, and the center of the trailing edge wall. Three discrete tones were measured at all three locations with corresponding Strouhal numbers (based on cavity opening length and approach flow velocity) equal to 0.24, 0.26, and 0.41. The amplitudes of each tone were approximately equal at each measurement location in the cavity. Measurements made at other approach flow conditions indicated that the approach flow velocity and the boundary layer thickness affected the frequency characteristics of the discrete tones.

  14. Sound Propagation in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Attenborough, Keith

    Propagation of sound close to the ground outdoors involves geometric spreading, air absorption, interaction with the ground, barriers, vegetation and refraction associated with wind and temperature gradients. After a brief survey of historical aspects of the study of outdoor sound and its applications, this chapter details the physical principles associated with various propagation effects, reviews data that demonstrate them and methods for predicting them. The discussion is concerned primarily with the relatively short ranges and spectra of interest when predicting and assessing community noise rather than the frequencies and long ranges of concern, for example, in infrasonic global monitoring or used for remote sensing of the atmosphere. Specific phenomena that are discussed include spreading losses, atmospheric absorption, diffraction by barriers and buildings, interaction of sound with the ground (ground waves, surface waves, ground impedance associated with porosity and roughness, and elasticity effects), propagation through crops, shrubs and trees, wind and temperature gradient effects, shadow zones and incoherence due to atmospheric turbulence. The chapter concludes by suggesting a few areas that require further research.

  15. Sound radiation from railway sleepers

    NASA Astrophysics Data System (ADS)

    Zhang, Xianying; Thompson, David J.; Squicciarini, Giacomo

    2016-05-01

    The sleepers supporting the rails of a railway track are an important source of noise at low frequencies. The sound radiation from the sleepers has been calculated using a three-dimensional boundary element model including the effect of both reflective and partially absorptive ground. When the sleeper flexibility and support stiffness are taken into account, it is found that the radiation ratio of the sleeper can be approximated by that of a rigid half-sleeper. When multiple sleepers are excited through the rail, their sound radiation is increased. This effect has been calculated for cases where the sleeper is embedded in a rigid or partially absorptive ground. It is shown that it is sufficient to consider only three sleepers in determining their radiation ratio when installed in track. At low frequencies the vibration of the track is localised to the three sleepers nearest the excitation point whereas at higher frequencies the distance between the sleepers is large enough for them to be treated independently. Consequently the sound radiation increases by up to 5 dB below 100 Hz compared with the result for a single sleeper whereas above 300 Hz the result can be approximated by that for a single sleeper. Measurements on a 1/5 scale model railway track are used to verify the numerical predictions with good agreement being found for all configurations.

  16. Underwater Sound Propagation from Marine Pile Driving.

    PubMed

    Reyff, James A

    2016-01-01

    Pile driving occurs in a variety of nearshore environments that typically have very shallow-water depths. The propagation of pile-driving sound in water is complex, where sound is directly radiated from the pile as well as through the ground substrate. Piles driven in the ground near water bodies can produce considerable underwater sound energy. This paper presents examples of sound propagation through shallow-water environments. Some of these examples illustrate the substantial variation in sound amplitude over time that can be critical to understand when computing an acoustic-based safety zone for aquatic species.

  17. Sound symbolism facilitates early verb learning.

    PubMed

    Imai, Mutsumi; Kita, Sotaro; Nagumo, Miho; Okada, Hiroyuki

    2008-10-01

    Some words are sound-symbolic in that they involve a non-arbitrary relationship between sound and meaning. Here, we report that 25-month-old children are sensitive to cross-linguistically valid sound-symbolic matches in the domain of action and that this sound symbolism facilitates verb learning in young children. We constructed a set of novel sound-symbolic verbs whose sounds were judged to match certain actions better than others, as confirmed by adult Japanese- as well as English speakers, and by 2- and 3-year-old Japanese-speaking children. These sound-symbolic verbs, together with other novel non-sound-symbolic verbs, were used in a verb learning task with 3-year-old Japanese children. In line with the previous literature, 3-year-olds could not generalize the meaning of novel non-sound-symbolic verbs on the basis of the sameness of action. However, 3-year-olds could correctly generalize the meaning of novel sound-symbolic verbs. These results suggest that iconic scaffolding by means of sound symbolism plays an important role in early verb learning.

  18. Prediction of sound fields in acoustical cavities using the boundary element method. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Kipp, C. R.; Bernhard, R. J.

    1985-01-01

    A method was developed to predict sound fields in acoustical cavities. The method is based on the indirect boundary element method. An isoparametric quadratic boundary element is incorporated. Pressure, velocity and/or impedance boundary conditions may be applied to a cavity by using this method. The capability to include acoustic point sources within the cavity is implemented. The method is applied to the prediction of sound fields in spherical and rectangular cavities. All three boundary condition types are verified. Cases with a point source within the cavity domain are also studied. Numerically determined cavity pressure distributions and responses are presented. The numerical results correlate well with available analytical results.

  19. Monitoring high-shear granulation using sound and vibration measurements.

    PubMed

    Briens, L; Daniher, D; Tallevi, A

    2007-02-22

    Sound and vibration measurements were investigated as monitoring methods for high-shear granulation. Five microphones and one accelerometer were placed at different locations on a 10 and a 25 l granulator and compared to find the optimum location and the effect of scale. The granulation process could be monitored using the mean frequency and root mean square sound pressure levels from acoustic emissions measured using a microphone in the filtered air exhaust of the granulators. These acoustic monitoring methods were successful for both the 10 and the 25 l granulation scales. The granulation phases, however, were more clearly defined for the larger scale granulation. The root mean square acceleration level from vibration measurements was also able to monitor the granulation, but only for the larger 25 l granulator.

  20. Passively minimizing structural sound radiation using shunted piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Bulent Ozer, M.; Royston, Thomas J.

    2003-10-01

    Two methods are presented to determine optimal inductance and resistance values of the shunt circuit across a piezoceramic material, which is bonded to a simply supported plate in order to minimize sound radiation from the plate. The first method (DH) makes use of den Hartog's damped vibration absorber principle. The second method (SM) uses the Sherman Morrison matrix inversion theorem. The effectiveness of each method is compared with regard to minimizing total acoustic sound-power radiation and acoustic pressure at a point. Optimization algorithms and case studies are presented using a linearized model for the piezoceramic and using a nonlinear model for the piezoceramic that accounts for the inherent dielectric hysteresis. Case studies demonstrate that the second method (SM) results in superior performance, under both linear and nonlinear system assumptions. Studies also illustrate that, if the nonlinearity in the system is significant, it must be incorporated in the optimization process.