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Sample records for accurate sound speed

  1. A new equation for the accurate calculation of sound speed in all oceans.

    PubMed

    Leroy, Claude C; Robinson, Stephen P; Goldsmith, Mike J

    2008-11-01

    A new equation is proposed for the calculation of sound speed in seawater as a function of temperature, salinity, depth, and latitude in all oceans and open seas, including the Baltic and the Black Sea. The proposed equation agrees to better than +/-0.2 m/s with two reference complex equations, each fitting the best available data corresponding to existing waters of different salinities. The only exceptions are isolated hot brine spots that may be found at the bottom of some seas. The equation is of polynomial form, with 14 terms and coefficients of between one and three significant figures. This is a substantial reduction in complexity compared to the more complex equations using pressure that need to be calculated according to depth and location. The equation uses the 1990 universal temperature scale (an elementary transformation is given for data based on the 1968 temperature scale). It is hoped that the equation will be useful to those who need to calculate sound speed in applications of marine acoustics.

  2. 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.

  3. Characterization of condenser microphones under different environmental conditions for accurate speed of sound measurements with acoustic resonators.

    PubMed

    Guianvarc'h, Cécile; Gavioso, Roberto M; Benedetto, Giuliana; Pitre, Laurent; Bruneau, Michel

    2009-07-01

    Condenser microphones are more commonly used and have been extensively modeled and characterized in air at ambient temperature and static pressure. However, several applications of interest for metrology and physical acoustics require to use these transducers in significantly different environmental conditions. Particularly, the extremely accurate determination of the speed of sound in monoatomic gases, which is pursued for a determination of the Boltzmann constant k by an acoustic method, entails the use of condenser microphones mounted within a spherical cavity, over a wide range of static pressures, at the temperature of the triple point of water (273.16 K). To further increase the accuracy achievable in this application, the microphone frequency response and its acoustic input impedance need to be precisely determined over the same static pressure and temperature range. Few previous works examined the influence of static pressure, temperature, and gas composition on the microphone's sensitivity. In this work, the results of relative calibrations of 1/4 in. condenser microphones obtained using an electrostatic actuator technique are presented. The calibrations are performed in pure helium and argon gas at temperatures near 273 K and in the pressure range between 10 and 600 kPa. These experimental results are compared with the predictions of a realistic model available in the literature, finding a remarkable good agreement. The model provides an estimate of the acoustic impedance of 1/4 in. condenser microphones as a function of frequency and static pressure and is used to calculate the corresponding frequency perturbations induced on the normal modes of a spherical cavity when this is filled with helium or argon gas.

  4. Characterization of condenser microphones under different environmental conditions for accurate speed of sound measurements with acoustic resonators

    SciTech Connect

    Guianvarc'h, Cecile; Pitre, Laurent; Bruneau, Michel

    2009-07-15

    Condenser microphones are more commonly used and have been extensively modeled and characterized in air at ambient temperature and static pressure. However, several applications of interest for metrology and physical acoustics require to use these transducers in significantly different environmental conditions. Particularly, the extremely accurate determination of the speed of sound in monoatomic gases, which is pursued for a determination of the Boltzmann constant k by an acoustic method, entails the use of condenser microphones mounted within a spherical cavity, over a wide range of static pressures, at the temperature of the triple point of water (273.16 K). To further increase the accuracy achievable in this application, the microphone frequency response and its acoustic input impedance need to be precisely determined over the same static pressure and temperature range. Few previous works examined the influence of static pressure, temperature, and gas composition on the microphone's sensitivity. In this work, the results of relative calibrations of 1/4 in. condenser microphones obtained using an electrostatic actuator technique are presented. The calibrations are performed in pure helium and argon gas at temperatures near 273 K and in the pressure range between 10 and 600 kPa. These experimental results are compared with the predictions of a realistic model available in the literature, finding a remarkable good agreement. The model provides an estimate of the acoustic impedance of 1/4 in. condenser microphones as a function of frequency and static pressure and is used to calculate the corresponding frequency perturbations induced on the normal modes of a spherical cavity when this is filled with helium or argon gas.

  5. The speed of sound in periodic ducts

    NASA Astrophysics Data System (ADS)

    Russo, Serena; Fabre, David; Giannetti, Flavio; Luchini, Paolo

    2016-01-01

    The flow through corrugated pipes is known to lead to strong whistling tones which may be harmful in many industrial appliances. The mechanism is known to originate from a coupling between vortex shedding at the edges of the cavities forming the wall of the tube and the acoustical modes of the pipe. The latter depend upon the effective velocity of sound ceff within the corrugated pipe. The purpose of this paper is to compute accurately this effective velocity of sound through an asymptotic calculation valid in the long-wave limit. Results are given for a number of geometries used in previous works, and compared with a simple model in which the effective speed of sound is function of the geometry of the pipe. The latter is found to work best for short cavities but significant disagreement is found for longer cavities. The case of 2D channels with a corrugated wall is also considered.

  6. Double difference tomography for breast ultrasound sound speed imaging

    NASA Astrophysics Data System (ADS)

    Li, Cuiping; Duric, Neb; Rama, Olsi; Burger, Angelika; Polin, Lisa; Nechiporchik, Nicole

    2011-03-01

    Breast ultrasound tomography is a rapidly developing imaging modality that has the potential to impact breast cancer screening and diagnosis. Double difference (DD) tomography utilizes more accurate differential time-of-flight (ToF) data to reconstruct the sound speed structure of the breast. It can produce more precise and better resolution sound speed images than standard tomography that uses absolute ToF data. We apply DD tomography to phantom data and excised mouse mammary glands data. DD tomograms demonstrate sharper sound speed contrast than the standard tomograms.

  7. NASA Now: The Speed of Sound

    NASA Video Gallery

    Learn about sonic booms and the speed of sound from aerospace engineer George Hatcher. Hatcher shares the excitement of physics in his description of the space shuttle re-entering Earth’s atmosph...

  8. NASA Now Minute: The Speed of Sound

    NASA Video Gallery

    Learn about sonic booms and the speed of sound from aerospace engineerGeorge Hatcher as he shares the excitement of physics in hisdescription of how the space shuttles reentered Earth’s atmosph...

  9. Time of flight measurement of speed of sound in air with a computer sound card

    NASA Astrophysics Data System (ADS)

    Aljalal, Abdulaziz

    2014-11-01

    A computer sound card and freely available audio editing software are used to measure accurately the speed of sound in air using the time-of-flight method. In addition to speed of sound measurement, inversion behaviour upon reflection from an open and closed end of a pipe is demonstrated. Also, it is demonstrated that the reflection at an open end of a pipe occurs slightly outside the pipe. The equipment needed is readily available to any student with access to a microphone, loudspeaker and computer.

  10. Measuring the Speed of Sound in Water

    ERIC Educational Resources Information Center

    Ward, Richard J.

    2015-01-01

    This paper begins with an early measurement of the speed of sound in water. A historical overview of the consequent development of SONAR and medical imaging is given. A method of measuring the speed suitable for demonstration to year 10 students is described in detail, and an explanation of its systematic error examined.

  11. Numerical Speed of Sound and its Application to Schemes for all Speeds

    NASA Technical Reports Server (NTRS)

    Liou, Meng-Sing; Edwards, Jack R.

    1999-01-01

    The concept of "numerical speed of sound" is proposed in the construction of numerical flux. It is shown that this variable is responsible for the accurate resolution of' discontinuities, such as contacts and shocks. Moreover, this concept can he readily extended to deal with low speed and multiphase flows. As a results, the numerical dissipation for low speed flows is scaled with the local fluid speed, rather than the sound speed. Hence, the accuracy is enhanced the correct solution recovered, and the convergence rate improved. We also emphasize the role of mass flux and analyze the behavior of this flux. Study of mass flux is important because the numerical diffusivity introduced in it can be identified. In addition, it is the term common to all conservation equations. We show calculated results for a wide variety of flows to validate the effectiveness of using the numerical speed of sound concept in constructing the numerical flux. We especially aim at achieving these two goals: (1) improving accuracy and (2) gaining convergence rates for all speed ranges. We find that while the performance at high speed range is maintained, the flux now has the capability of performing well even with the low: speed flows. Thanks to the new numerical speed of sound, the convergence is even enhanced for the flows outside of the low speed range. To realize the usefulness of the proposed method in engineering problems, we have also performed calculations for complex 3D turbulent flows and the results are in excellent agreement with data.

  12. 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.

  13. [An adaptive ultrasound sound speed optimization based on image contrast analysis].

    PubMed

    Li, Xiaoying; Liu, Dongquan

    2011-12-01

    In order to get real time ultrasound images with clear structure and improved contrast, an adaptive ultrasound sound speed optimization method based on image contrast analysis was investigated. It firstly introduced the dynamic beamforming of ultrasound system, as well as the definition of assumed system's sound speed and the true sound speed propagated in tissues the degrade image quality due to their mismatch was also discussed. After given the pixel gray level value based ultrasound image contrast ratio, the basic idea to precisely estimate the true sound speed for real time system sound speed was proposed. Algorithms have been verified both in tissue-mimicking phantoms with known sound speeds and in vivo ultrasound images, compared with other existing method. The testing results showed that this new method not only produced accurate sound speed for ultrasound image optimization, but also finely met the critical computation requirement for real time applications.

  14. An Inexpensive and Versatile Version of Kundt's Tube for Measuring the Speed of Sound in Air

    NASA Astrophysics Data System (ADS)

    Papacosta, Pangratios; Linscheid, Nathan

    2016-01-01

    Experiments that measure the speed of sound in air are common in high schools and colleges. In the Kundt's tube experiment, a horizontal air column is adjusted until a resonance mode is achieved for a specific frequency of sound. When this happens, the cork dust in the tube is disturbed at the displacement antinode regions. The location of the displacement antinodes enables the measurement of the wavelength of the sound that is being used. This paper describes a design that uses a speaker instead of the traditional aluminum rod as the sound source. This allows the use of multiple sound frequencies that yield a much more accurate speed of sound in air.

  15. Direct Measurement of the Speed of Sound Using a Microphone and a Speaker

    ERIC Educational Resources Information Center

    Gómez-Tejedor, José A.; Castro-Palacio, Juan C.; Monsoriu, Juan A.

    2014-01-01

    We present a simple and accurate experiment to obtain the speed of sound in air using a conventional speaker and a microphone connected to a computer. A free open source digital audio editor and recording computer software application allows determination of the time-of-flight of the wave for different distances, from which the speed of sound is…

  16. Accurate Sound Velocity Measurement in Ocean Near-Surface Layer

    NASA Astrophysics Data System (ADS)

    Lizarralde, D.; Xu, B. L.

    2015-12-01

    Accurate sound velocity measurement is essential in oceanography because sound is the only wave that can propagate in sea water. Due to its measuring difficulties, sound velocity is often not measured directly but instead calculated from water temperature, salinity, and depth, which are much easier to obtain. This research develops a new method to directly measure the sound velocity in the ocean's near-surface layer using multi-channel seismic (MCS) hydrophones. This system consists of a device to make a sound pulse and a long cable with hundreds of hydrophones to record the sound. The distance between the source and each receiver is the offset. The time it takes the pulse to arrive to each receiver is the travel time.The errors of measuring offset and travel time will affect the accuracy of sound velocity if we calculated with just one offset and one travel time. However, by analyzing the direct arrival signal from hundreds of receivers, the velocity can be determined as the slope of a straight line in the travel time-offset graph. The errors in distance and time measurement result in only an up or down shift of the line and do not affect the slope. This research uses MCS data of survey MGL1408 obtained from the Marine Geoscience Data System and processed with Seismic Unix. The sound velocity can be directly measured to an accuracy of less than 1m/s. The included graph shows the directly measured velocity verses the calculated velocity along 100km across the Mid-Atlantic continental margin. The directly measured velocity shows a good coherence to the velocity computed from temperature and salinity. In addition, the fine variations in the sound velocity can be observed, which is hardly seen from the calculated velocity. Using this methodology, both large area acquisition and fine resolution can be achieved. This directly measured sound velocity will be a new and powerful tool in oceanography.

  17. Aerodynamics of sounding rockets at supersonic speeds

    NASA Astrophysics Data System (ADS)

    Vira, N. R.

    This dissertation presents a practical and low cost method of computing the aerodynamic characteristics of vehicles such as sounding rockets, high speed bombs, projectiles and guided missiles in supersonic flight. The vehicle configuration consists of a slender axisymmetric body with a conical or ogive noise, cylinders, shoulders and boattails, if any, and have sets of two, three or four fins. Geometry of the fin cross section can be single wedge, double wedge, modified single wedge or modified double wedge. First the aerodynamics of the fins and the body are analyzed separately; then fin body and fore and aft fin interferences are accounted for when they are combined to form the total vehicle. Results and formulas documented in this work are the basis of the supersonic portion of the Theoretical Aerodynamic Derivatives (TAD) computer program operating at the NASA Goddard Space Flight Center.

  18. Processing data, for improved, accuracy, from device for measuring speed of sound in a gas

    DOEpatents

    Owen, Thomas E.

    2006-09-19

    A method, used in connection with a pulse-echo type sensor for determining the speed of sound in a gas, for improving the accuracy of speed of sound measurements. The sensor operates on the principle that speed of sound can be derived from the difference between the two-way travel time of signals reflected from two different target faces of the sensor. This time difference is derived by computing the cross correlation between the two reflections. The cross correlation function may be fitted to a parabola whose vertex represents the optimum time coordinate of the coherence peak, thereby providing an accurate measure of the two-way time diffference.

  19. Effect of the acoustic environment on adjoint sound speed inversions

    NASA Astrophysics Data System (ADS)

    Richards, Edward

    The recent prevalence of low cost robotic platforms such as oceanographic gliders has increased the availability of long-term measurements of the ocean environment. Gliders can take direct measurements of the ocean sound speed environment, which is of interest in many ocean acoustic problems, including source localization and tomography. These measurements, however, have a low spatial-temporal resolution that makes them difficult to use directly. These measurements have the potential to provide an accurate environmental parameterization for acoustic inversions, which could in turn be used to measure the sound speed field at a much higher spatial-temporal resolution. This study uses glider measurements to provide the environmental parameterization used in the adjoint inversion method. The adjoint method calculates the gradient of a cost function describing the mismatch between observed data and acoustic model predictions with respect to the ocean sound speed. This gradient is a measure of how changing the sound speed at any point in the acoustic environment would affect this misfit. This cost function and its gradient information is then used as inputs to a numerical optimization routine, which efficiently finds a local minimum. There are two challenges of this method addressed in this study; the first is restricting the search space of this inversion. Proper parameterization of the inversion will ensure that the local minimum found in the numerical optimization routine is the correct result of the inversion. This parameterization allows for the combination of the relative strengths of both methods of measuring the sound speed field, the robust direct measurement of the glider and the near instantaneous result of an acoustic inversion. A covariance matrix is created from glider measurements of the range dependent sound speed field, which is then decomposed into an empirical orthogonal function (EOF) base. The mean profile and the significant EOF bases then form the

  20. Speed of sound in muscle for use in sonomicrometry.

    PubMed

    Marsh, Richard L

    2016-12-08

    Converting ultrasound transit time into a measure of distance when using sonomicrometry requires that the speed of sound be known. A number of different values for the speed of sound in muscle have been assumed in studies of skeletal and cardiac muscle, and in some cases the effect of temperature has been ignored. The speed of ultrasound with frequencies greater than 1MHz in skeletal and cardiac muscle is briefly reviewed, including the effects of temperature and contractile state. A simplified equation for the speed of sound in pure water is presented for the temperature range from 0-50°C. This equation can be used when calibrating sonomicrometer transducers in water. The data available indicate that the speed of sound in both cardiac and skeletal muscle can be approximated by multiplying the speed of sound in pure water at the measurement temperature by 1.045. Differences in the speed of sound in the longitudinal and transverse directions and changes with contractile state appear to be small and in most cases can probably be safely ignored. The normal variation in muscle composition does not greatly affect the speed of ultrasound in muscle, but investigators placing sonomicrometer transducers near tendons should be conscious of the much greater speed of sound in tendon and variation with loading.

  1. Measurement of the speed of sound in ice

    NASA Technical Reports Server (NTRS)

    Smith, A. C.; Kishoni, D.

    1986-01-01

    The data presented demonstrate the gathering of sound speed measurements in refrigerated ice, using both compressional and shear waves, on the basis of ice thickness and sound wave time-of-travel parameters. Clear and sharp echo reflections were obtained for both compressional and shear waves at the aluminum/ice and ice/aluminum interfaces for ice at -26 C; ice formed at various conditions can have different sound speeds, depending on the density and elastic constants.

  2. 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."…

  3. Sound Speed and Attenuation in Multiphase Media

    DTIC Science & Technology

    2012-03-15

    factor for bottom loss models. Originally this research concerned the description of the low frequency, LF, radiation and scattering of sound from...observations. The quandary was: why do investigators find exponents n between 1.6 and 1.87 less than 2? Numerical studies have shown obvious factors ...Nantucket Sound Experiment sound transmission experiment [17] where roughness and internal waves are not a factor required a power exponent of n = 1.87

  4. Accurate torque-speed performance prediction for brushless dc motors

    NASA Astrophysics Data System (ADS)

    Gipper, Patrick D.

    Desirable characteristics of the brushless dc motor (BLDCM) have resulted in their application for electrohydrostatic (EH) and electromechanical (EM) actuation systems. But to effectively apply the BLDCM requires accurate prediction of performance. The minimum necessary performance characteristics are motor torque versus speed, peak and average supply current and efficiency. BLDCM nonlinear simulation software specifically adapted for torque-speed prediction is presented. The capability of the software to quickly and accurately predict performance has been verified on fractional to integral HP motor sizes, and is presented. Additionally, the capability of torque-speed prediction with commutation angle advance is demonstrated.

  5. A Visual Measurement of the Speed of Sound.

    ERIC Educational Resources Information Center

    Winters, Loren M.

    1993-01-01

    Describes a method of measuring the speed of sound that can be done in front of a class on a lab table in 15 minutes, be understood by junior high school students, and be engaging and instructive for students at high school and college levels as well. Provides schematic for sound trigger. (MVL)

  6. Determining the Speed of Sound Using the Doppler Effect.

    ERIC Educational Resources Information Center

    Gagne, Richard.

    1996-01-01

    Presents a simple but effective experiment that uses ultrasonic transducers and some basic electronics to study the speed of sound using the Doppler effect. Eliminates the noise problems associated with most sound experiments. Discusses the theory, and describes the apparatus and procedure. (JRH)

  7. Adaptive sound speed correction for abdominal ultrasonography: preliminary results

    NASA Astrophysics Data System (ADS)

    Jin, Sungmin; Kang, Jeeun; Song, Tai-Kyung; Yoo, Yangmo

    2013-03-01

    Ultrasonography has been conducting a critical role in assessing abdominal disorders due to its noninvasive, real-time, low cost, and deep penetrating capabilities. However, for imaging obese patients with a thick fat layer, it is challenging to achieve appropriate image quality with a conventional beamforming (CON) method due to phase aberration caused by the difference between sound speeds (e.g., 1580 and 1450m/s for liver and fat, respectively). For this, various sound speed correction (SSC) methods that estimate the accumulated sound speed for a region-of interest (ROI) have been previously proposed. However, with the SSC methods, the improvement in image quality was limited only for a specific depth of ROI. In this paper, we present the adaptive sound speed correction (ASSC) method, which can enhance the image quality for whole depths by using estimated sound speeds from two different depths in the lower layer. Since these accumulated sound speeds contain the respective contributions of layers, an optimal sound speed for each depth can be estimated by solving contribution equations. To evaluate the proposed method, the phantom study was conducted with pre-beamformed radio-frequency (RF) data acquired with a SonixTouch research package (Ultrasonix Corp., Canada) with linear and convex probes from the gel pad-stacked tissue mimicking phantom (Parker Lab. Inc., USA and Model539, ATS, USA) whose sound speeds are 1610 and 1450m/s, respectively. From the study, compared to the CON and SSC methods, the ASSC method showed the improved spatial resolution and information entropy contrast (IEC) for convex and linear array transducers, respectively. These results indicate that the ASSC method can be applied for enhancing image quality when imaging obese patients in abdominal ultrasonography.

  8. 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.

  9. Bubbles that Change the Speed of Sound

    NASA Astrophysics Data System (ADS)

    Planinšič, Gorazd; Etkina, Eugenia

    2012-11-01

    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."2 In this paper we describe a simple and robust experiment that allows an easy audio and visual demonstration of the same effect (unfortunately without the chocolate) and offers several possibilities for student investigations. In addition to the demonstration of the above effect, the experiments described below provide an excellent opportunity for students to devise and test explanations with simple equipment.

  10. Measuring the Speed of Sound through Gases Using Nitrocellulose

    ERIC Educational Resources Information Center

    Molek, Karen Sinclair; Reyes, Karl A.; Burnette, Brandon A.; Stepherson, Jacob R.

    2015-01-01

    Measuring the heat capacity ratios, ?, of gases either through adiabatic expansion or sound velocity is a well established physical chemistry experiment. The most accurate experiments depend on an exact determination of sound origin, which necessitates the use of lasers or a wave generator, where time zero is based on an electrical trigger. Other…

  11. Sound Affects the Speed of Visual Processing

    ERIC Educational Resources Information Center

    Keetels, Mirjam; Vroomen, Jean

    2011-01-01

    The authors examined the effects of a task-irrelevant sound on visual processing. Participants were presented with revolving clocks at or around central fixation and reported the hand position of a target clock at the time an exogenous cue (1 clock turning red) or an endogenous cue (a line pointing toward 1 of the clocks) was presented. A…

  12. In vivo breast sound-speed imaging with ultrasound tomography

    SciTech Connect

    Huang, Lianjie; Li, Cuiping; Duric, Neb; Littrup, Peter

    2009-01-01

    We discuss a bent-ray ultrasound tomography algorithm with total-variation (TV) regularization. We have applied this algorithm to 61 in vivo breast datasets collected with our in-house clinical prototype for imaging sound-speed distributions in the breast. Our analysis showed that TV regularization could preserve sharper lesion edges than the classic Tikhonov regularization. Furthermore, the image quality of our TV bent-ray sound-speed tomograms was superior to that of the straight-ray counterparts for all types of breasts within BI-RADS density categories 1-4. For all four breast types from fatty to dense, the improvements for average sharpness (in the unit of (m{center_dot} s) {sup -1}) of lesion edges in our TV bent-ray tomograms are between 2.1 to 3.4 fold compared to the straight ray tomograms. Reconstructed sound-speed tomograms illustrated that our algorithm could successfully image fatty and glandular tissues within the breast. We calculated the mean sound-speed values for fatty tissue and breast parenchyma as 1422 {+-} 9 mls (mean{+-} SD) and1487 {+-} 21 mls, respectively. Based on 32 lesions in a cohort of 61 patients, we also found that the mean sound-speed for malignant breast lesions (1548{+-}17 mls) was higher, on average, than that of benign ones (1513{+-}27 mls) (one-sided psound-speed tomograms can be used to assess breast density (, and therefore, breast cancer risk), as well as detect and help differentiate breast lesions. Finally, our sound-speed tomograms may also be a useful tool to monitor clinical response of breast cancer patients to neo-adjuvant chemotherapy.

  13. 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.

  14. Using a High-Speed Camera to Measure the Speed of Sound

    ERIC Educational Resources Information Center

    Hack, William Nathan; Baird, William H.

    2012-01-01

    The speed of sound is a physical property that can be measured easily in the lab. However, finding an inexpensive and intuitive way for students to determine this speed has been more involved. The introduction of affordable consumer-grade high-speed cameras (such as the Exilim EX-FC100) makes conceptually simple experiments feasible. Since the…

  15. The impact of sound speed errors on medical ultrasound imaging.

    PubMed

    Anderson, M E; McKeag, M S; Trahey, G E

    2000-06-01

    The results of a quantitative study of the impact of sound speed errors on the spatial resolution and amplitude sensitivity of a commercial medical ultrasound scanner are presented in the context of their clinical significance. The beamforming parameters of the scanner were manipulated to produce sound speed errors ranging over +/-8% while imaging a wire target and an attenuating, speckle-generating phantom. For the wire target, these errors produced increases in lateral beam width of up to 320% and reductions in peak echo amplitude of up to 10.5 dB. In the speckle-generating phantom, these errors produced increases in speckle intensity correlation cell area of up to 92% and reductions in mean speckle brightness of up to 5.6 dB. These results are applied in statistical analyses of two detection tasks of clinical relevance. The first is of low contrast lesion detectability, predicting the changes in the correct decision probability as a function of lesion size, contrast, and sound speed error. The second is of point target detectability, predicting the changes in the correct decision probability as function of point target reflectivity and sound speed error. Representative results of these analyses are presented and their implications for clinical imaging are discussed. In general, sound speed errors have a more significant impact on point target detectability over lesion detectability by these analyses, producing up to a 22% reduction in correct decisions for a typical error.

  16. A new process to estimate the speed of sound using three-sensor method

    NASA Astrophysics Data System (ADS)

    Simon, Alexandre; Martinez-Molina, John-Jairo; Fortes-Patella, Regiane

    2016-01-01

    As a part of complex works aiming at the evaluation of the pump's dynamic transfer matrix, this paper presents an estimation method of the speed of sound in water and water/air flows using three pressure transducer measurements. The experimental study was carried out at the CREMHyG acoustic test rig, for a void ratio varying from 0 to 1 % and for amplitudes of speed of sound from 100 to 1400 m/s. To estimate the speed of sound in this large range of amplitude, a new post-treatment approach was developed, based on the least mean squares method. Experimental results obtained were compared with existing theoretical models, and a very good agreement was observed. The post-processing appeared fast, robust and accurate for all the mono- and diphasic flows analyzed. The results presented in this paper can be applied, for instance, in acoustic characterization of the hydraulic systems, mainly in the case of space rocket turbopump applications.

  17. A method for direct localized sound speed estimates using registered virtual detectors.

    PubMed

    Byram, Brett C; Trahey, Gregg E; Jensen, Jørgen A

    2012-07-01

    Accurate sound speed estimates are desirable in a number of fields. In an effort to increase the spatial resolution of sound speed estimates, a new method is proposed for direct measurement of sound speed between arbitrary spatial locations. The method uses the sound speed estimator developed by Anderson and Trahey. Their least squares fit of the received waveform's curvature provides an estimate of the wave's point of origin. The point of origin and the delay profile calculated from the fit are used to arrive at a spatially registered virtual detector. Between a pair of registered virtual detectors, a spherical wave is propagated. By beamforming the data, the time-of-flight between the two virtual sources can be calculated. From this information, the local sound speed can be estimated. Validation of the estimator is made using phantom and simulation data. The set of test phantoms consisted of both homogeneous and inhomogeneous media. Several different inhomogeneous phantom configurations were used for the physical validation. The simulation validation focused on the limits of target depth and signal-to-noise ratio on virtual detector registration. The simulations also compare the impact of two- and three-layer inhomogeneous media. The phantom results varied based on signal-to-noise ratio and geometry. The results for all cases were generally less than 1% mean error and standard deviation. The simulation results varied somewhat with depth and F/#, but primarily, they varied with signal-to-noise ratio and geometry. With two-layer geometries, the algorithm has a worst-case spatial registration bias of 0.02%. With three-layer geometries, the axial registration error gets worse with a bias magnitude up to 2.1% but is otherwise relatively stable over depth. The stability over depth of the bias in a given medium still allows for accurate sound speed estimates with a mean relative error less than 0.2%.

  18. A speed of sound based feed water temperature sensor

    NASA Astrophysics Data System (ADS)

    Klason, P.; Holmsten, M.; Andersson, A.; Lau, P.; Kok, G. J. P.

    2013-09-01

    Controlling thermal power in the feed water line of a power plant presupposes both accurate flow and temperature measurement. In this application the temperature measurement is usually a single Pt-100. This results in a measurement error of several kelvin. In this study we have investigated two different sensors based on the speed of sound (SoS) in the flowing medium for measuring the average temperature across a flow pipe cross-section. This is a task within the on-going European research project called ENG-06. The two SoS-based temperature measuring sensors were investigated under laboratory conditions. Investigations were done using both homogenous and non-homogenous temperature distributions with temperature differences up to 25 K. In addition the influence of pressure (50-200 kPa) and flow rates (0.5-2 m/s) on the SoS devices were also investigated. Our results show that the SoS-based temperature principle is working. Furthermore, depending on the measurement conditions a SoS temperature measurement device significantly can reduce the deviation to the reference sensor compared with a single Pt-100 sensor. Relative reductions in the deviation to the reference of 20-85 % were possible to achieve. This opens for the possibility of increasing the energy efficiency in power plants as aimed for in the ENG-06 project.

  19. Metastable sound speed in gas-liquid mixtures

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    A new method of calculating speed of sound for two-phase flow is presented. The new equation assumes no phase change during the propagation of an acoustic disturbance and assumes that only the total entropy of the mixture remains constant during the process. The new equation predicts single-phase values for the speed of sound in the limit of all gas or all liquid and agrees with available two-phase, air-water sound speed data. Other expressions used in the two-phase flow literature for calculating two-phase, metastable sound speed are reviewed and discussed. Comparisons are made between the new expression and several of the previous expressions -- most notably a triply isentropic equation as used, a triply isentropic equation as used, among others, by Karplus and by Wallis. Appropriate differences are pointed out and a thermodynamic criterion is derived which must be satisfied in order for the triply isentropic expression to be thermodynamically consistent. This criterion is not satisfied for the cases examined, which included two-phase nitrogen, air-water, two-phase parahydrogen, and steam-water. Consequently, the new equation derived is found to be superior to the other equations reviewed.

  20. NEW APPROACHES: Speed of sound in tuning fork metal

    NASA Astrophysics Data System (ADS)

    Narayanan, V. Anantha; Narayanan, Radha

    1996-11-01

    A procedure to find the speed of sound in tuning fork metal is described. The formula needed is extracted from the literature and explained. Since the equipment needed for this project is readily available in most high school and introductory level college science laboratories, this exercise can be done without any additional cost.

  1. Experimenting with End-Correction and the Speed of Sound

    ERIC Educational Resources Information Center

    LoPresto, Michael C.

    2011-01-01

    What follows is an alternative to the standard tuning fork and quarter-wave tube speed of sound experiment. Rather than adjusting the water level in a glass or plastic tube to vary the length of an air column, a set of resonance tubes of different lengths is used. The experiment still demonstrates the principles of standing waves in air columns…

  2. B modes and the sound speed of primordial fluctuations

    NASA Astrophysics Data System (ADS)

    Palma, Gonzalo A.; Soto, Alex

    2015-03-01

    It was recently shown that a large value of the tensor to scalar ratio r implies a constraint on the minimum value of the sound speed cs of primordial curvature perturbations during inflation that is stronger than current bounds coming from non-Gaussianity measurements. Here we consider additional aspects related to the measurement of B modes that may provide additional leverage to constrain the sound speed parametrizing noncanonical models of inflation. We find that a confirmation of the consistency relation r =-8 nt between the tensor to scalar ratio r and the tensor spectral index nt is not enough to rule out noncanonical models of inflation with a sound speed cs different from unity. To determine whether inflation was canonical or not, one requires knowledge of additional parameters, such as the running of the spectral index of scalar perturbations α . We also study how other parameters related to the ultraviolet completion of inflation modify the dependence of r on cs. For instance, we find that heavy degrees of freedom interacting with curvature fluctuations generically tend to make the constraint on the sound speed stronger. Our results, combined with future observations of primordial B modes, may help to constrain the background evolution of noncanonical models of inflation.

  3. First-arrival traveltime sound speed inversion with a priori information

    PubMed Central

    Hooi, Fong Ming; Carson, Paul L.

    2014-01-01

    Purpose: A first-arrival travel-time sound speed algorithm presented byTarantola [Inverse Problem Theory and Methods for Model Parameter Estimation (SIAM, Philadelphia, PA, 2005)] is adapted to the medical ultrasonics setting. Through specification of a covariance matrix for the object model, the algorithm allows for natural inclusion of physical a priori information of the object. The algorithm's ability to accurately and robustly reconstruct a complex sound speed distribution is demonstrated on simulation and experimental data using a limited aperture. Methods: The algorithm is first demonstrated generally in simulation with a numerical breast phantom imaged in different geometries. As this work is motivated by the authors' limited aperture dual sided ultrasound breast imaging system, experimental data are acquired with a Verasonics system with dual, 128 element, linear L7-4 arrays. The transducers are automatically calibrated for usage in the eikonal forward model.A priori information such as knowledge of correlated regions within the object is obtained via segmentation of B-mode images generated from synthetic aperture imaging. Results: As one illustration of the algorithm's facility for inclusion ofa priori information, physically grounded regularization is demonstrated in simulation. The algorithm's practicality is then demonstrated through experimental realization in limited aperture cases. Reconstructions of sound speed distributions of various complexity are improved through inclusion of a priori information. The sound speed maps are generally reconstructed with accuracy within a few m/s. Conclusions: This paper demonstrates the ability to form sound speed images using two opposed commercial linear arrays to mimic ultrasound image acquisition in the compressed mammographic geometry. The ability to create reasonably good speed of sound images in the compressed mammographic geometry allows images to be readily coregistered to tomosynthesis image volumes for

  4. Non-contact sound speed measurement by optical probing of beam deflection due to sound wave.

    PubMed

    Jung, Sung Soo; Kim, Yong Tae; Pu, Yu Cheon; Kim, Min Gon; Kim, Ho Chul

    2006-01-01

    We report a non-contact and non-invasive method of sound speed measurement by optical probing of deflected laser beam due to normally incident degenerated shock wave. In this study the shock wave from an exploding wire was degenerated to an ordinary sound wave at the distance exceeding 0.23 m. Temporal resolution of the deflected beam signal was improved by passing through an adequate electronic high-pass filter, as a result we obtained a better temporal resolution than that of the acoustic pressure detection by PZT transducer in terms of rising time. The spatial resolution was improved by passing the refracted beam signal into the edge of focusing lens to make a larger deflection angle. Sound speed was calculated by monitoring the time of flight of transient deflected signal at the predetermined position. Sound speed has been measured in air, distilled water and acryl, agreed well with the published values. The sound speed measured in the solution of glycerin, magnesium sulfate (MgSO4), and dimethylformamide with various mole fractions also agrees within 3% of relative error with those measured in the present work by ultrasonic pulse echo method. The results suggest that the method proposed is to be reliable and reproducible.

  5. Effects of small variations of speed of sound in optoacoustic tomographic imaging

    SciTech Connect

    Deán-Ben, X. Luís; Ntziachristos, Vasilis; Razansky, Daniel

    2014-07-15

    Purpose: Speed of sound difference in the imaged object and surrounding coupling medium may reduce the resolution and overall quality of optoacoustic tomographic reconstructions obtained by assuming a uniform acoustic medium. In this work, the authors investigate the effects of acoustic heterogeneities and discuss potential benefits of accounting for those during the reconstruction procedure. Methods: The time shift of optoacoustic signals in an acoustically heterogeneous medium is studied theoretically by comparing different continuous and discrete wave propagation models. A modification of filtered back-projection reconstruction is subsequently implemented by considering a straight acoustic rays model for ultrasound propagation. The results obtained with this reconstruction procedure are compared numerically and experimentally to those obtained assuming a heuristically fitted uniform speed of sound in both full-view and limited-view optoacoustic tomography scenarios. Results: The theoretical analysis showcases that the errors in the time-of-flight of the signals predicted by considering the straight acoustic rays model tend to be generally small. When using this model for reconstructing simulated data, the resulting images accurately represent the theoretical ones. On the other hand, significant deviations in the location of the absorbing structures are found when using a uniform speed of sound assumption. The experimental results obtained with tissue-mimicking phantoms and a mouse postmortem are found to be consistent with the numerical simulations. Conclusions: Accurate analysis of effects of small speed of sound variations demonstrates that accounting for differences in the speed of sound allows improving optoacoustic reconstruction results in realistic imaging scenarios involving acoustic heterogeneities in tissues and surrounding media.

  6. Speed of sound in bubble-free ice.

    PubMed

    Vogt, Christian; Laihem, Karim; Wiebusch, Christopher

    2008-12-01

    The speed of sound in a large volume of bubble-free ice was measured with high accuracy using a linear array of six piezoceramic lead zirconium titanate (PZT) receivers. This array was deployed in an approximately 3 m(3) water tank, which was cooled down to -20 degrees C. The freezing process was performed inside a cooling container. Bubble-free ice was obtained using a freeze control unit, which filters and degases the water during the freezing process. A dedicated geometry was used to position PZT receivers and an emitter such that systematic errors were minimized. With this setup the longitudinal and the transverse components of the speed of sound were measured at temperatures between 17 and 0 degrees C in water and between 0 and -20 degrees C in ice with an uncertainty of approximately 0.3%.

  7. Speed of sound in nuclear matter and Skyrme effective interactions

    SciTech Connect

    Su, R.K.; Kuo, T.T.S.

    1987-02-01

    Using a nuclear equation of state derived from a finite-temperature Green's function method and the Skyrme effective interactions SkI, SkIII and SkM*, the authors have calculated the speed of sound in symmetric nuclear matter. For certain densities and temperatures, this speed is found to become super-luminous. Causal boundaries in the density-temperature plane are determined, and they indicate that SkM* is a more desirable effective interaction than SkI and SkIII. Comparison with a similar calculation by Osnes and Strottman is made.

  8. Speed of Sound in Metal Pipes: An Inexpensive Lab

    ERIC Educational Resources Information Center

    Huggins, Elisha

    2008-01-01

    Our favorite demonstration for sound waves is to set up a compressional pulse on a horizontally stretched Slinky[TM]. One can easily watch the pulse move back and forth at a speed of the order of one meter per second. Watching this demonstration, it occurred to us that the same thing might happen in a steel pipe if you hit the end of the pipe with…

  9. Sound sources in a low speed ducted rotor

    NASA Astrophysics Data System (ADS)

    Stephens, David Bruce

    The objective of this research was to improve the understanding of the sound source mechanisms in a low speed ducted fan through experimental and analytical efforts. To this end, a new experimental model with carefully controlled boundary conditions was developed. A new method for quantifying the net acoustic transfer function between the rotor and an observer was found. This transfer function caused by the duct can significantly affect the spectral character of the radiated sound. Quantifying this function enables the study of the rotor sound source, without need of other methods for considering duct effects. A new formulation for predicting the noise generated by a ducted rotor interacting with a casing boundary layer has been developed. The method accounts for the streamwise-elongated turbulent structures that have been recently observed in flat-plate boundary layers. An approximation for the duct boundary layer two-point correlation function allows the net sound source to be estimated. Finally, the self-noise generated by a ducted rotor was studied. The flow rate through the rotor was varied independently from the rotor rotation rate in order change the mean lift on the blades. Measurements of the flow field around the rotor were found to provide insight to the mechanisms of sound that depend on mean loading conditions.

  10. SOUND-SPEED TOMOGRAPHY USING FIRST-ARRIVAL TRANSMISSION ULTRASOUND FOR A RING ARRAY

    SciTech Connect

    HUANG, LIANJIE; QUAN, YOULI

    2007-01-31

    Sound-speed tomography images can be used for cancer detection and diagnosis. Tumors have generally higher sound speeds than the surrounding tissue. Quality and resolution of tomography images are primarily determined by the insonification/illumination aperture of ultrasound and the capability of the tomography method for accurately handling heterogeneous nature of the breast. We investigate the capability of an efficient time-of-flight tomography method using transmission ultrasound from a ring array for reconstructing sound-speed images of the breast. The method uses first arrival times of transmitted ultrasonic signals emerging from non-beamforming ultrasound transducers located around a ring. It properly accounts for ray bending within the breast by solving the eikonal equation using a finite-difference scheme. We test and validate the time-of-flight transmission tomography method using synthetic data for numerical breast phantoms containing various objects. In our simulation, the objects are immersed in water within a ring array. Two-dimensional synthetic data are generated using a finite-difference scheme to solve acoustic-wave equation in heterogeneous media. We study the reconstruction accuracy of the tomography method for objects with different sizes and shapes as well as different perturbations from the surrounding medium. In addition, we also address some specific data processing issues related to the tomography. Our tomography results demonstrate that the first-arrival transmission tomography method can accurately reconstruct objects larger than approximately five wavelengths of the incident ultrasound using a ring array.

  11. Sound-speed tomography using first-arrival transmission ultrasound for a ring array

    NASA Astrophysics Data System (ADS)

    Quan, Youli; Huang, Lianjie

    2007-03-01

    Sound-speed tomography images can be used for cancer detection and diagnosis. Tumors have generally higher sound speeds than the surrounding tissue. Quality and resolution of tomography images are primarily determined by the insonification/illumination aperture of ultrasound and the capability of the tomography method for accurately handling heterogeneous nature of the breast. We investigate the capability of an efficient time-of-flight tomography method using transmission ultrasound from a ring array for reconstructing sound-speed images of the breast. The method uses first-arrival times of transmitted ultrasonic signals emerging from non-beamforming ultrasound transducers located around a ring. It properly accounts for ray bending within the breast by solving the eikonal equation using a finite-difference scheme. We test and validate the time-of-flight transmission tomography method using synthetic data for numerical breast phantoms containing various objects. In our simulation, the objects are immersed in water within a ring array. Two-dimensional synthetic data are generated using a finite-difference scheme to solve acoustic-wave equation in heterogeneous media. We study the reconstruction accuracy of the tomography method for objects with different sizes and shapes as well as different perturbations from the surrounding medium. In addition, we also address some specific data processing issues related to the tomography. Our tomography results demonstrate that the first-arrival transmission tomography method can accurately reconstruct objects larger than approximately five wavelengths of the incident ultrasound using a ring array.

  12. Fault diagnosis of motor bearing with speed fluctuation via angular resampling of transient sound signals

    NASA Astrophysics Data System (ADS)

    Lu, Siliang; Wang, Xiaoxian; He, Qingbo; Liu, Fang; Liu, Yongbin

    2016-12-01

    Transient signal analysis (TSA) has been proven an effective tool for motor bearing fault diagnosis, but has yet to be applied in processing bearing fault signals with variable rotating speed. In this study, a new TSA-based angular resampling (TSAAR) method is proposed for fault diagnosis under speed fluctuation condition via sound signal analysis. By applying the TSAAR method, the frequency smearing phenomenon is eliminated and the fault characteristic frequency is exposed in the envelope spectrum for bearing fault recognition. The TSAAR method can accurately estimate the phase information of the fault-induced impulses using neither complicated time-frequency analysis techniques nor external speed sensors, and hence it provides a simple, flexible, and data-driven approach that realizes variable-speed motor bearing fault diagnosis. The effectiveness and efficiency of the proposed TSAAR method are verified through a series of simulated and experimental case studies.

  13. On the estimation of sound speed in two-dimensional Yukawa fluids

    SciTech Connect

    Semenov, I. L. Thomas, H. M.; Khrapak, S. A.

    2015-11-15

    The longitudinal sound speed in two-dimensional Yukawa fluids is estimated using the conventional hydrodynamic expression supplemented by appropriate thermodynamic functions proposed recently by Khrapak et al. [Phys. Plasmas 22, 083706 (2015)]. In contrast to the existing approaches, such as quasi-localized charge approximation (QLCA) and molecular dynamics simulations, our model provides a relatively simple estimate for the sound speed over a wide range of parameters of interest. At strong coupling, our results are shown to be in good agreement with the results obtained using the QLCA approach and those derived from the phonon spectrum for the triangular lattice. On the other hand, our model is also expected to remain accurate at moderate values of the coupling strength. In addition, the obtained results are used to discuss the influence of the strong coupling effects on the adiabatic index of two-dimensional Yukawa fluids.

  14. Determination of equivalent sound speed profiles for ray tracing in near-ground sound propagation.

    PubMed

    Prospathopoulos, John M; Voutsinas, Spyros G

    2007-09-01

    The determination of appropriate sound speed profiles in the modeling of near-ground propagation using a ray tracing method is investigated using a ray tracing model which is capable of performing axisymmetric calculations of the sound field around an isolated source. Eigenrays are traced using an iterative procedure which integrates the trajectory equations for each ray launched from the source at a specific direction. The calculation of sound energy losses is made by introducing appropriate coefficients to the equations representing the effect of ground and atmospheric absorption and the interaction with the atmospheric turbulence. The model is validated against analytical and numerical predictions of other methodologies for simple cases, as well as against measurements for nonrefractive atmospheric environments. A systematic investigation for near-ground propagation in downward and upward refractive atmosphere is made using experimental data. Guidelines for the suitable simulation of the wind velocity profile are derived by correlating predictions with measurements.

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

    ERIC Educational Resources Information Center

    Amrani, D.

    2013-01-01

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

  16. Accurate measurement of streamwise vortices in low speed aerodynamic flows

    NASA Astrophysics Data System (ADS)

    Waldman, Rye M.; Kudo, Jun; Breuer, Kenneth S.

    2010-11-01

    Low Reynolds number experiments with flapping animals (such as bats and small birds) are of current interest in understanding biological flight mechanics, and due to their application to Micro Air Vehicles (MAVs) which operate in a similar parameter space. Previous PIV wake measurements have described the structures left by bats and birds, and provided insight to the time history of their aerodynamic force generation; however, these studies have faced difficulty drawing quantitative conclusions due to significant experimental challenges associated with the highly three-dimensional and unsteady nature of the flows, and the low wake velocities associated with lifting bodies that only weigh a few grams. This requires the high-speed resolution of small flow features in a large field of view using limited laser energy and finite camera resolution. Cross-stream measurements are further complicated by the high out-of-plane flow which requires thick laser sheets and short interframe times. To quantify and address these challenges we present data from a model study on the wake behind a fixed wing at conditions comparable to those found in biological flight. We present a detailed analysis of the PIV wake measurements, discuss the criteria necessary for accurate measurements, and present a new dual-plane PIV configuration to resolve these issues.

  17. Sound transmission loss of windows on high speed trains

    NASA Astrophysics Data System (ADS)

    Zhang, Yumei; Xiao, Xinbiao; Thompson, David; Squicciarini, Giacomo; Wen, Zefeng; Li, Zhihui; Wu, Yue

    2016-09-01

    The window is one of the main components of the high speed train car body structure through which noise can be transmitted. To study the windows’ acoustic properties, the vibration of one window of a high speed train has been measured for a running speed of 250 km/h. The corresponding interior noise and the noise in the wheel-rail area have been measured simultaneously. The experimental results show that the window vibration velocity has a similar spectral shape to the interior noise. Interior noise source identification further indicates that the window makes a contribution to the interior noise. Improvement of the window's Sound Transmission Loss (STL) can reduce the interior noise from this transmission path. An STL model of the window is built based on wave propagation and modal superposition methods. From the theoretical results, the window's STL property is studied and several factors affecting it are investigated, which provide indications for future low noise design of high speed train windows.

  18. Ultrasonic attenuation and speed of sound of cornstarch suspensions.

    PubMed

    Johnson, Benjamin L; Holland, Mark R; Miller, James G; Katz, Jonathan I

    2013-03-01

    The goal of this study is to contribute to the physics underlying the material properties of suspensions that exhibit shear thickening through the ultrasonic characterization of suspensions of cornstarch in a density-matched solution. Ultrasonic measurements at frequencies in the range of 4 to 8 MHz of the speed of sound and the frequency-dependent attenuation properties are reported for concentrations of cornstarch in a density-matched aqueous (cesium chloride brine) suspension, ranging up to 40% cornstarch. The speed of sound is found to range from 1483 ± 10 m/s in pure brine to 1765 ± 9 m/s in the 40% cornstarch suspension. The bulk modulus of a granule of cornstarch is inferred to be 1.2(± 0.1) × 10(10) Pa. The attenuation coefficient at 5 MHz increases from essentially zero in brine to 12.0 ± 1.2 dB/cm at 40% cornstarch.

  19. Adaptation to audiovisual asynchrony modulates the speeded detection of sound

    PubMed Central

    Navarra, Jordi; Hartcher-O'Brien, Jessica; Piazza, Elise; Spence, Charles

    2009-01-01

    The brain adapts to asynchronous audiovisual signals by reducing the subjective temporal lag between them. However, it is currently unclear which sensory signal (visual or auditory) shifts toward the other. According to the idea that the auditory system codes temporal information more precisely than the visual system, one should expect to find some temporal shift of vision toward audition (as in the temporal ventriloquism effect) as a result of adaptation to asynchronous audiovisual signals. Given that visual information gives a more exact estimate of the time of occurrence of distal events than auditory information (due to the fact that the time of arrival of visual information regarding an external event is always closer to the time at which this event occurred), the opposite result could also be expected. Here, we demonstrate that participants' speeded reaction times (RTs) to auditory (but, critically, not visual) stimuli are altered following adaptation to asynchronous audiovisual stimuli. After receiving “baseline” exposure to synchrony, participants were exposed either to auditory-lagging asynchrony (VA group) or to auditory-leading asynchrony (AV group). The results revealed that RTs to sounds became progressively faster (in the VA group) or slower (in the AV group) as participants' exposure to asynchrony increased, thus providing empirical evidence that speeded responses to sounds are influenced by exposure to audiovisual asynchrony. PMID:19458252

  20. 40 CFR 205.54-1 - Low speed sound emission test procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Low speed sound emission test....54-1 Low speed sound emission test procedures. (a) Instrumentation. The following instrumentation shall be used, where applicable. (1) A sound level meter which meets the Type 1 requirements of ANSI...

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Low speed sound emission test....54-1 Low speed sound emission test procedures. (a) Instrumentation. The following instrumentation shall be used, where applicable. (1) A sound level meter which meets the Type 1 requirements of ANSI...

  2. 40 CFR 205.54-1 - Low speed sound emission test procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Low speed sound emission test....54-1 Low speed sound emission test procedures. (a) Instrumentation. The following instrumentation shall be used, where applicable. (1) A sound level meter which meets the Type 1 requirements of ANSI...

  3. 40 CFR 205.54-1 - Low speed sound emission test procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Low speed sound emission test....54-1 Low speed sound emission test procedures. (a) Instrumentation. The following instrumentation shall be used, where applicable. (1) A sound level meter which meets the Type 1 requirements of ANSI...

  4. 40 CFR 205.54-1 - Low speed sound emission test procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Low speed sound emission test....54-1 Low speed sound emission test procedures. (a) Instrumentation. The following instrumentation shall be used, where applicable. (1) A sound level meter which meets the Type 1 requirements of ANSI...

  5. Sound speed estimation and source localization with linearization and particle filtering.

    PubMed

    Lin, Tao; Michalopoulou, Zoi-Heleni

    2014-03-01

    A method is developed for the estimation of source location and sound speed in the water column relying on linearization. The Jacobian matrix, necessary for the proposed linearization approach, includes derivatives with respect to empirical orthogonal function coefficients instead of sound speed directly. First, the inversion technique is tested on synthetic arrival times, using Gaussian distributions for the errors in the considered arrival times. The approach is efficient, requiring a few iterations, and produces accurate results. Probability densities of the estimates are calculated for different levels of noise in the arrival times. Subsequently, particle filtering is employed for the estimation of arrival times from signals recorded during the Shallow Water 06 experiment. It has been shown in the past that particle filtering can be employed for the successful estimation of multipath arrival times from short-range data and, consequently, in geometry, bathymetry, and sound speed inversion. Here probability density functions of arrival times computed via particle filtering are propagated backward through the proposed inversion process. Inversion estimates are consistent with values reported in the literature for the same quantities. Last it is shown that results are consistent with estimates resulting from fast simulated annealing applied to the same data.

  6. Approach to accurately measuring the speed of optical precursors

    SciTech Connect

    Li Chuanfeng; Zhou Zongquan; Guo Guangcan; Jeong, Heejeong

    2011-10-15

    Precursors can serve as a bound on the speed of information with dispersive medium. We propose a method to identify the speed of optical wave fronts using polarization-based interference in a solid-state device, which can bound the accuracy of the speed of wave fronts to less than 10{sup -4} with conventional experimental conditions. Our proposal may have important implications for optical communications and fast information processing.

  7. Speed of sound estimation with active PZT element for thermal monitoring during ablation therapy: feasibility study

    NASA Astrophysics Data System (ADS)

    Kim, Younsu; Guo, Xiaoyu; Cheng, Alexis; Boctor, Emad M.

    2016-04-01

    Controlling the thermal dose during ablation therapy is instrumental to successfully removing the tumor while preserving the surrounding healthy tissue. In the practical scenario, surgeons must be able to determine the ablation completeness in the tumor region. Various methods have been proposed to monitor it, one of which uses ultrasound since it is a common intraoperative imaging modality due to its non-invasive, cost-effective, and convenient natures. In our approach, we propose to use time of flight (ToF) information to estimate speed of sound changes. Accurate speed of sound estimation is crucial because it is directly correlated with temperature change and subsequent determination of ablation completeness. We divide the region of interest in a circular fashion with a variable radius from the ablator tip. We introduce the concept of effective speed of sound in each of the sub-regions. Our active PZT element control system facilitates this unique approach by allowing us to acquire one-way ToF information between the PZT element and each of the ultrasound elements. We performed a simulation and an experiment to verify feasibility of this method. The simulation result showed that we could compute the effective speed of sound within 0.02m/s error in our discrete model. We also perform a sensitivity analysis for this model. Most of the experimental results had less than 1% error. Simulation using a Gaussian continuous model with multiple PZT elements is also demonstrated. We simulate the effect of the element location one the optimization result.

  8. 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.

  9. Method and apparatus for ultrasonic doppler velocimetry using speed of sound and reflection mode pulsed wideband doppler

    DOEpatents

    Shekarriz, Alireza; Sheen, David M.

    2000-01-01

    According to the present invention, a method and apparatus rely upon tomographic measurement of the speed of sound and fluid velocity in a pipe. The invention provides a more accurate profile of velocity within flow fields where the speed of sound varies within the cross-section of the pipe. This profile is obtained by reconstruction of the velocity profile from the local speed of sound measurement simultaneously with the flow velocity. The method of the present invention is real-time tomographic ultrasonic Doppler velocimetry utilizing a to plurality of ultrasonic transmission and reflection measurements along two orthogonal sets of parallel acoustic lines-of-sight. The fluid velocity profile and the acoustic velocity profile are determined by iteration between determining a fluid velocity profile and measuring local acoustic velocity until convergence is reached.

  10. Bound on the speed of sound from holography

    SciTech Connect

    Cherman, Aleksey; Cohen, Thomas D.; Nellore, Abhinav

    2009-09-15

    We show that the squared speed of sound v{sub s}{sup 2} is bounded from above at high temperatures by the conformal value of 1/3 in a class of strongly coupled four-dimensional field theories, given some mild technical assumptions. This class consists of field theories that have gravity duals sourced by a single-scalar field. There are no known examples to date of field theories with gravity duals for which v{sub s}{sup 2} exceeds 1/3 in energetically favored configurations. We conjecture that v{sub s}{sup 2}=1/3 represents an upper bound for a broad class of four-dimensional theories.

  11. Speed of sound and temperature in the ocean by Brillouin scattering

    NASA Technical Reports Server (NTRS)

    Hirschberg, J. G.; Byrne, J. D.; Wouters, A. W.; Boynton, G. C.

    1984-01-01

    A method is described to measure the speed of sound and the temperature in the sea as functions of depth. Backscattered laser light is analyzed with an interferometric spectrometer. The speed of sound at very short acoustic wavelengths is obtained directly from the wavelength shift of the Brillouin scattered light, and the temperature is deduced from the speed of sound together with auxiliary information on depth and salinity. Experiments are described.

  12. Numerical assessment of accurate measurements of laminar flame speed

    NASA Astrophysics Data System (ADS)

    Goulier, Joules; Bizon, Katarzyna; Chaumeix, Nabiha; Meynet, Nicolas; Continillo, Gaetano

    2016-12-01

    In combustion, the laminar flame speed constitutes an important parameter that reflects the chemistry of oxidation for a given fuel, along with its transport and thermal properties. Laminar flame speeds are used (i) in turbulent models used in CFD codes, and (ii) to validate detailed or reduced mechanisms, often derived from studies using ideal reactors and in diluted conditions as in jet stirred reactors and in shock tubes. End-users of such mechanisms need to have an assessment of their capability to predict the correct heat released by combustion in realistic conditions. In this view, the laminar flame speed constitutes a very convenient parameter, and it is then very important to have a good knowledge of the experimental errors involved with its determination. Stationary configurations (Bunsen burners, counter-flow flames, heat flux burners) or moving flames (tubes, spherical vessel, soap bubble) can be used. The spherical expanding flame configuration has recently become popular, since it can be used at high pressures and temperatures. With this method, the flame speed is not measured directly, but derived through the recording of the flame radius. The method used to process the radius history will have an impact on the estimated flame speed. Aim of this work is to propose a way to derive the laminar flame speed from experimental recording of expanding flames, and to assess the error magnitude.

  13. Soft porous silicone rubbers with ultra-low sound speeds in acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Ba, Abdoulaye; Kovalenko, Artem; Aristégui, Christophe; Mondain-Monval, Olivier; Brunet, Thomas

    2017-01-01

    Soft porous silicone rubbers are demonstrated to exhibit extremely low sound speeds of tens of m/s for these dense materials, even for low porosities of the order of a few percent. Our ultrasonic experiments show a sudden drop of the longitudinal sound speed with the porosity, while the transverse sound speed remains constant. For such porous elastomeric materials, we propose simple analytical expressions for these two sound speeds, derived in the framework of Kuster and Toksöz, revealing an excellent agreement between the theoretical predictions and the experimental results for both longitudinal and shear waves. Acoustic attenuation measurements also complete the characterization of these soft porous materials.

  14. Soft porous silicone rubbers with ultra-low sound speeds in acoustic metamaterials

    PubMed Central

    Ba, Abdoulaye; Kovalenko, Artem; Aristégui, Christophe; Mondain-Monval, Olivier; Brunet, Thomas

    2017-01-01

    Soft porous silicone rubbers are demonstrated to exhibit extremely low sound speeds of tens of m/s for these dense materials, even for low porosities of the order of a few percent. Our ultrasonic experiments show a sudden drop of the longitudinal sound speed with the porosity, while the transverse sound speed remains constant. For such porous elastomeric materials, we propose simple analytical expressions for these two sound speeds, derived in the framework of Kuster and Toksöz, revealing an excellent agreement between the theoretical predictions and the experimental results for both longitudinal and shear waves. Acoustic attenuation measurements also complete the characterization of these soft porous materials. PMID:28054661

  15. Photoacoustically Measured Speeds of Sound of Liquid HBO2: On Unlocking the Fuel Potential of Boron

    SciTech Connect

    Bastea, S; Crowhurst, J; Armstrong, M; ., N T

    2010-03-24

    Elucidation of geodynamic, geochemical, and shock induced processes is often limited by challenges to accurately determine molecular fluid equations of state (EOS). High pressure liquid state reactions of carbon species underlie physiochemical mechanisms such as differentiation of planetary interiors, deep carbon sequestration, propellant deflagration, and shock chemistry. Here we introduce a versatile photoacoustic technique developed to measure accurate and precise speeds of sound (SoS) of high pressure molecular fluids and fluid mixtures. SoS of an intermediate boron oxide, HBO{sub 2} are measured up to 0.5 GPa along the 277 C isotherm. A polarized Exponential-6 interatomic potential form, parameterized using our SoS data, enables EOS determinations and corresponding semi-empirical evaluations of > 2000 C thermodynamic states including energy release from bororganic formulations. Our thermochemical model propitiously predicts boronated hydrocarbon shock Hugoniot results.

  16. A Time-of-Flight Method to Measure the Speed of Sound Using a Stereo Sound Card

    ERIC Educational Resources Information Center

    Carvalho, Carlos C.; dos Santos, J. M. B. Lopes; Marques, M. B.

    2008-01-01

    Most homes in developed countries have a sophisticated data acquisition board, namely the PC sound board. Designed to be able to reproduce CD-quality stereo sound, it must have a sampling rate of at least 44 kHz and have very accurate timing between the two stereo channels. With a very simple adaptation of a pair of regular PC microphones, a…

  17. Variation of ultrasound image lateral spectrum with assumed speed of sound and true scatterer density.

    PubMed

    Gyöngy, Miklós; Kollár, Sára

    2015-02-01

    One method of estimating sound speed in diagnostic ultrasound imaging consists of choosing the speed of sound that generates the sharpest image, as evaluated by the lateral frequency spectrum of the squared B-mode image. In the current work, simulated and experimental data on a typical (47 mm aperture, 3.3-10.0 MHz response) linear array transducer are used to investigate the accuracy of this method. A range of candidate speeds of sound (1240-1740 m/s) was used, with a true speed of sound of 1490 m/s in simulations and 1488 m/s in experiments. Simulations of single point scatterers and two interfering point scatterers at various locations with respect to each other gave estimate errors of 0.0-2.0%. Simulations and experiments of scatterer distributions with a mean scatterer spacing of at least 0.5 mm gave estimate errors of 0.1-4.0%. In the case of lower scatterer spacing, the speed of sound estimates become unreliable due to a decrease in contrast of the sharpness measure between different candidate speeds of sound. This suggests that in estimating speed of sound in tissue, the region of interest should be dominated by a few, sparsely spaced scatterers. Conversely, the decreasing sensitivity of the sharpness measure to speed of sound errors for higher scatterer concentrations suggests a potential method for estimating mean scatterer spacing.

  18. Causal field theory with an infinite speed of sound

    NASA Astrophysics Data System (ADS)

    Afshordi, Niayesh; Chung, Daniel J. H.; Geshnizjani, Ghazal

    2007-04-01

    We introduce a model of scalar field dark energy, Cuscuton, which can be realized as the incompressible (or infinite speed of sound) limit of a scalar field theory with a noncanonical kinetic term (or k-essence). Even though perturbations of Cuscuton propagate superluminally, we show that they have a locally degenerate phase space volume (or zero entropy), implying that they cannot carry any microscopic information, and thus the theory is causal. Even coupling to ordinary scalar fields cannot lead to superluminal signal propagation. Furthermore, we show that the family of constant field hypersurfaces is the family of constant mean curvature hypersurfaces, which are the analogs of soap films (or soap bubbles) in Euclidian space. This enables us to find the most general solution in 1+1 dimensions, whose properties motivate conjectures for global degeneracy of the phase space in higher dimensions. Finally, we show that the Cuscuton action can model the continuum limit of the evolution of a field with discrete degrees of freedom and argue why it is protected against quantum corrections at low energies. While this paper mainly focuses on interesting features of Cuscuton in a Minkowski space-time, a companion paper examines cosmology with Cuscuton dark energy.

  19. SOLAR CYCLE VARIATION OF SOUND SPEED INSIDE THE SUN

    SciTech Connect

    Mullan, D. J.; MacDonald, J.; Rabello-Soares, M. C.

    2012-08-10

    Empirical radial profiles of the changes in sound speed inside the Sun between solar minimum and solar maximum have been extracted from Michelson Doppler Imager data by Baldner and Basu and Rabello-Soares. Here, we compare these results with the theoretical radial profiles predicted by a model of magnetic inhibition of convective onset: In the model, the degree of magnetic inhibition is characterized by a parameter {delta}, which is essentially the ratio of magnetic pressure to gas pressure. We find that the theoretical profiles overlap significantly with the empirical results in the outer half of the convection zone. But differences in the deeper layers indicate that the model needs to be modified there. The main result that emerges in the present comparison is that the value of {delta} must be larger near the surface than at great depth. A secondary result is that, in the course of the solar cycle, the magnetic field magnitude at the base of the convection zone may be out of phase with the field near the surface.

  20. Spherical collapse in quintessence models with zero speed of sound

    SciTech Connect

    Creminelli, Paolo; D'Amico, Guido; Noreña, Jorge; Senatore, Leonardo; Vernizzi, Filippo E-mail: norena@sissa.it E-mail: senatore@ias.edu

    2010-03-01

    We study the spherical collapse model in the presence of quintessence with negligible speed of sound. This case is particularly motivated for w < −1 as it is required by stability. As pressure gradients are negligible, quintessence follows dark matter during the collapse. The spherical overdensity behaves as a separate closed FLRW universe, so that its evolution can be studied exactly. We derive the critical overdensity for collapse and we use the extended Press-Schechter theory to study how the clustering of quintessence affects the dark matter mass function. The effect is dominated by the modification of the linear dark matter growth function. A larger effect occurs on the total mass function, which includes the quintessence overdensities. Indeed, here quintessence constitutes a third component of virialized objects, together with baryons and dark matter, and contributes to the total halo mass by a fraction ∼ (1+w)Ω{sub Q}/Ω{sub m}. This gives a distinctive modification of the total mass function at low redshift.

  1. Causal field theory with an infinite speed of sound

    SciTech Connect

    Afshordi, Niayesh; Chung, Daniel J. H.; Geshnizjani, Ghazal

    2007-04-15

    We introduce a model of scalar field dark energy, Cuscuton, which can be realized as the incompressible (or infinite speed of sound) limit of a scalar field theory with a noncanonical kinetic term (or k-essence). Even though perturbations of Cuscuton propagate superluminally, we show that they have a locally degenerate phase space volume (or zero entropy), implying that they cannot carry any microscopic information, and thus the theory is causal. Even coupling to ordinary scalar fields cannot lead to superluminal signal propagation. Furthermore, we show that the family of constant field hypersurfaces is the family of constant mean curvature hypersurfaces, which are the analogs of soap films (or soap bubbles) in Euclidian space. This enables us to find the most general solution in 1+1 dimensions, whose properties motivate conjectures for global degeneracy of the phase space in higher dimensions. Finally, we show that the Cuscuton action can model the continuum limit of the evolution of a field with discrete degrees of freedom and argue why it is protected against quantum corrections at low energies. While this paper mainly focuses on interesting features of Cuscuton in a Minkowski space-time, a companion paper examines cosmology with Cuscuton dark energy.

  2. An approach to get thermodynamic properties from speed of sound

    NASA Astrophysics Data System (ADS)

    Núñez, M. A.; Medina, L. A.

    2017-01-01

    An approach for estimating thermodynamic properties of gases from the speed of sound u, is proposed. The square u2, the compression factor Z and the molar heat capacity at constant volume C V are connected by two coupled nonlinear partial differential equations. Previous approaches to solving this system differ in the conditions used on the range of temperature values [Tmin,Tmax]. In this work we propose the use of Dirichlet boundary conditions at Tmin, Tmax. The virial series of the compression factor Z = 1+Bρ+Cρ2+… and other properties leads the problem to the solution of a recursive set of linear ordinary differential equations for the B, C. Analytic solutions of the B equation for Argon are used to study the stability of our approach and previous ones under perturbation errors of the input data. The results show that the approach yields B with a relative error bounded basically by that of the boundary values and the error of other approaches can be some orders of magnitude lager.

  3. Determination of volume fractions in two-phase flows from sound speed measurement

    SciTech Connect

    Chaudhuri, Anirban; Sinha, Dipen N.; Osterhoudt, Curtis F.

    2012-08-15

    Accurate measurement of the composition of oil-water emulsions within the process environment is a challenging problem in the oil industry. Ultrasonic techniques are promising because they are non-invasive and can penetrate optically opaque mixtures. This paper presents a method of determining the volume fractions of two immiscible fluids in a homogenized two-phase flow by measuring the speed of sound through the composite fluid along with the instantaneous temperature. Two separate algorithms are developed by representing the composite density as (i) a linear combination of the two densities, and (ii) a non-linear fractional formulation. Both methods lead to a quadratic equation with temperature dependent coefficients, the root of which yields the volume fraction. The densities and sound speeds are calibrated at various temperatures for each fluid component, and the fitted polynomial is used in the final algorithm. We present results when the new algorithm is applied to mixtures of crude oil and process water from two different oil fields, and a comparison of our results with a Coriolis meter; the difference between mean values is less than 1%. Analytical and numerical studies of sensitivity of the calculated volume fraction to temperature changes and calibration errors are also presented.

  4. Comparison of sound speed measurements on two different ultrasound tomography devices

    NASA Astrophysics Data System (ADS)

    Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Sherman, Mark; Gierach, Gretchen; Malyarenko, Antonina

    2014-03-01

    Ultrasound tomography (UST) employs sound waves to produce three-dimensional images of breast tissue and precisely measures the attenuation of sound speed secondary to breast tissue composition. High breast density is a strong breast cancer risk factor and sound speed is directly proportional to breast density. UST provides a quantitative measure of breast density based on three-dimensional imaging without compression, thereby overcoming the shortcomings of many other imaging modalities. The quantitative nature of the UST breast density measures are tied to an external standard, so sound speed measurement in breast tissue should be independent of specific hardware. The work presented here compares breast sound speed measurement obtained with two different UST devices. The Computerized Ultrasound Risk Evaluation (CURE) system located at the Karmanos Cancer Institute in Detroit, Michigan was recently replaced with the SoftVue ultrasound tomographic device. Ongoing clinical trials have used images generated from both sets of hardware, so maintaining consistency in sound speed measurements is important. During an overlap period when both systems were in the same exam room, a total of 12 patients had one or both of their breasts imaged on both systems on the same day. There were 22 sound speed scans analyzed from each system and the average breast sound speeds were compared. Images were either reconstructed using saved raw data (for both CURE and SoftVue) or were created during the image acquisition (saved in DICOM format for SoftVue scans only). The sound speed measurements from each system were strongly and positively correlated with each other. The average difference in sound speed between the two sets of data was on the order of 1-2 m/s and this result was not statistically significant. The only sets of images that showed a statistical difference were the DICOM images created during the SoftVue scan compared to the SoftVue images reconstructed from the raw data

  5. Comparison of sound speed measurements on two different ultrasound tomography devices.

    PubMed

    Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Sherman, Mark; Gierach, Gretchen; Malyarenko, Antonina

    2014-03-20

    Ultrasound tomography (UST) employs sound waves to produce three-dimensional images of breast tissue and precisely measures the sound speed of breast tissue composition. High breast density is a strong breast cancer risk factor and sound speed is directly proportional to breast density. UST provides a quantitative measure of breast density based on three-dimensional imaging without compression, thereby overcoming the shortcomings of many other imaging modalities. The quantitative nature of the UST breast density measures are tied to an external standard, so sound speed measurement in breast tissue should be independent of specific hardware. The work presented here compares breast sound speed measurement obtained with two different UST devices. The Computerized Ultrasound Risk Evaluation (CURE) system located at the Karmanos Cancer Institute in Detroit, Michigan was recently replaced with the SoftVue ultrasound tomographic device. Ongoing clinical trials have used images generated from both sets of hardware, so maintaining consistency in sound speed measurements is important. During an overlap period when both systems were in the same exam room, a total of 12 patients had one or both of their breasts imaged on both systems on the same day. There were 22 sound speed scans analyzed from each system and the average breast sound speeds were compared. Images were either reconstructed using saved raw data (for both CURE and SoftVue) or were created during the image acquisition (saved in DICOM format for SoftVue scans only). The sound speed measurements from each system were strongly and positively correlated with each other. The average difference in sound speed between the two sets of data was on the order of 1-2 m/s and this result was not statistically significant. The only sets of images that showed a statistical difference were the DICOM images created during the SoftVue scan compared to the SoftVue images reconstructed from the raw data. However, the discrepancy

  6. Comparison of sound speed measurements on two different ultrasound tomography devices

    PubMed Central

    Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Sherman, Mark; Gierach, Gretchen; Malyarenko, Antonina

    2014-01-01

    Ultrasound tomography (UST) employs sound waves to produce three-dimensional images of breast tissue and precisely measures the sound speed of breast tissue composition. High breast density is a strong breast cancer risk factor and sound speed is directly proportional to breast density. UST provides a quantitative measure of breast density based on three-dimensional imaging without compression, thereby overcoming the shortcomings of many other imaging modalities. The quantitative nature of the UST breast density measures are tied to an external standard, so sound speed measurement in breast tissue should be independent of specific hardware. The work presented here compares breast sound speed measurement obtained with two different UST devices. The Computerized Ultrasound Risk Evaluation (CURE) system located at the Karmanos Cancer Institute in Detroit, Michigan was recently replaced with the SoftVue ultrasound tomographic device. Ongoing clinical trials have used images generated from both sets of hardware, so maintaining consistency in sound speed measurements is important. During an overlap period when both systems were in the same exam room, a total of 12 patients had one or both of their breasts imaged on both systems on the same day. There were 22 sound speed scans analyzed from each system and the average breast sound speeds were compared. Images were either reconstructed using saved raw data (for both CURE and SoftVue) or were created during the image acquisition (saved in DICOM format for SoftVue scans only). The sound speed measurements from each system were strongly and positively correlated with each other. The average difference in sound speed between the two sets of data was on the order of 1-2 m/s and this result was not statistically significant. The only sets of images that showed a statistical difference were the DICOM images created during the SoftVue scan compared to the SoftVue images reconstructed from the raw data. However, the discrepancy

  7. Sound speed as a proxy variable to temperature in Fram Strait.

    PubMed

    Dushaw, Brian D; Sagen, Hanne; Beszczynska-Möller, Agnieszka

    2016-07-01

    The application of ocean acoustic tomography in Fram Strait requires a careful assessment of the accuracy to which estimates of sound speed from tomography can be converted to estimates of temperature. The Fram Strait environment is turbulent, with warm, salty, northward-flowing North Atlantic water interacting with cold, fresh, southward-flowing Arctic water. The nature of this environment suggests that salinity could play an important role with respect to sound speed. The properties of sound speed with respect to temperature and salinity in this environment were examined using climatological and in situ glider data. In cold water, a factor of about 4.5 m s(-1) °C(-1) can be used to scale between sound speed and temperature. In situ data obtained by gliders were used to determine the ambiguities between temperature, salinity, and sound speed. Tomography provides a depth-averaging measurement. While errors in the sound speed-temperature conversion at particular depths may be 0.2 °C or larger, particularly within 50 m of the surface, such errors are suppressed when the depth is averaged. Using a simple scale factor to compute temperature from sound speed introduced an error of about 20 m °C for depth-averaged temperature, a value less than formal uncertainties estimated from acoustic tomography.

  8. 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.

  9. Speed of sound as a function of temperature for ultrasonic propagation in soybean oil

    NASA Astrophysics Data System (ADS)

    Oliveira, P. A.; Silva, R. M. B.; Morais, G. C.; Alvarenga, A. V.; Costa-Félix, R. P. B.

    2016-07-01

    Ultrasound has been used for characterization of liquid in several productive sectors and research. This work presents the studied about the behavior of the speed of sound in soybean oil with increasing temperature. The pulse echo technique allowed observing that the speed of sound decreases linearly with increasing temperature in the range 20 to 50 °C at 1 MHz. As result, a characteristic function capable to reproduce the speed of sound behavior in soybean oil, as a function of temperature was established, with the respective measurement uncertainty.

  10. Compact sound-speed sensor for quartz enhanced photoacoustic spectroscopy based applications

    NASA Astrophysics Data System (ADS)

    Liu, Kun; Dong, Lei; Tittel, Frank K.

    2015-04-01

    A compact sound-speed sensor based on a phase difference method was developed. The sensor employs a U-shaped stainless steel tube with two holes located on its front and back ends, which serves as a sound wave guide. The phase difference between the two holes was measured using two mini-microphones by means of a phase-sensitive detection technique. This method offers the advantage of eliminating the influence of signal fluctuations. The frequency of a sound source offered by a loudspeaker can be scanned between 1 kHz and 50 kHz. The slope of the phase difference as a function of frequency was obtained by scanning the frequency of the sound source. The speed of sound was retrieved from the rate of change of the phase difference. The performance of the sensor was evaluated over a wide range of speeds of sound from 260 m/s to 1010 m/s in different gas mixtures. The measured speed of sound was found to be in good agreement with the theoretical value for the sound-speed sensor.

  11. Laryngeal High-Speed Videoendoscopy: Rationale and Recommendation for Accurate and Consistent Terminology

    ERIC Educational Resources Information Center

    Deliyski, Dimitar D.; Hillman, Robert E.; Mehta, Daryush D.

    2015-01-01

    Purpose: The authors discuss the rationale behind the term "laryngeal high-speed videoendoscopy" to describe the application of high-speed endoscopic imaging techniques to the visualization of vocal fold vibration. Method: Commentary on the advantages of using accurate and consistent terminology in the field of voice research is…

  12. Analysis of a method for computing the speed of sound in a medium with inclusions

    NASA Astrophysics Data System (ADS)

    Ivanov, V. P.

    2016-08-01

    A method for computing the speed of sound in a medium with inclusions with the help of the theory of multiple scattering of a plane wave on a doubly periodic multilayered lattice of transparent particles is proposed.

  13. An Inexpensive and Versatile Version of Kundt's Tube for Measuring the Speed of Sound in Air

    ERIC Educational Resources Information Center

    Papacosta, Pangratios; Linscheid, Nathan

    2016-01-01

    Experiments that measure the speed of sound in air are common in high schools and colleges. In the Kundt's tube experiment, a horizontal air column is adjusted until a resonance mode is achieved for a specific frequency of sound. When this happens, the cork dust in the tube is disturbed at the displacement antinode regions. The location of the…

  14. Speed of sound in hadronic matter using non-extensive Tsallis statistics

    NASA Astrophysics Data System (ADS)

    Khuntia, Arvind; Sahoo, Pragati; Garg, Prakhar; Sahoo, Raghunath; Cleymans, Jean

    2016-09-01

    The speed of sound ( cs) is studied to understand the hydrodynamical evolution of the matter created in heavy-ion collisions. The quark-gluon plasma (QGP) formed in heavy-ion collisions evolves from an initial QGP to the hadronic phase via a possible mixed phase. Due to the system expansion in a first-order phase transition scenario, the speed of sound reduces to zero as the specific heat diverges. We study the speed of sound for systems which deviate from a thermalized Boltzmann distribution using non-extensive Tsallis statistics. In the present work, we calculate the speed of sound as a function of temperature for different q-values for a hadron resonance gas. We observe a similar mass cut-off behaviour in the non-extensive case for c2s by including heavier particles, as is observed in the case of a hadron resonance gas following equilibrium statistics. Also, we explicitly show that the temperature where the mass cut-off starts varies with the q-parameter which hints at a relation between the degree of non-equilibrium and the limiting temperature of the system. It is shown that for values of q above approximately 1.13 all criticality disappears in the speed of sound, i.e. the decrease in the value of the speed of sound, observed at lower values of q, disappears completely.

  15. Measuring the Speed of Sound Using Only a Computer

    ERIC Educational Resources Information Center

    Bin, Mo

    2013-01-01

    corresponding time to cover that distance. But sound travels rapidly, covering about one meter in three milliseconds. This challenge can be met by using only a computer and an external microphone. A fixed frequency (1000 Hz) is fed into the computer's speaker and the…

  16. Evaluation of eye tissue elasticity by means of sound propagation speed measuring in vivo

    NASA Astrophysics Data System (ADS)

    Crispim, Joao; Bogar, Adriano; Allemann, Norma; Neto, Jarbas C. C.; Chamon, Wallace

    2015-06-01

    Introduction: To date, it has never been demonstrated the propagation sound speed in human corneas and lens in vivo. With the advent of Optical Coherence Tomography (OCT), it became possible to determine the dimensions of the ocular tissues without the interference of sound propagation speed and to use this information to define the real propagation sound speed for each patient and individualized structure. Aim: To determine the sound propagation speed in the cornea and lens from patients that theoretically exhibits differences in tissue elasticity (normal corneas and keratoconus, corneas of young and elderly patients, in addition to clear crystalline lens from young and elderly patients with cataract). Then, relate the determined velocity in each group with the expected tissue elasticity of the cornea and lens. Methods: We studied 100 eyes from 50 patients: 50 with keratoconus and no cataract and 50 with cataract and no corneal changes. All patients measured corneal and lens thickness by ultrasound methods (Ultrasonic Biomicroscopy - UBM and Ultrasonic Pachymetry - USP) and by OCT (RTVue®, Lenstar® and Visante®), then were divided into 2 groups: Group 1 (Cornea) analyzed the central corneal thickness (UBM, USP, RTVue®, Visante®, Lenstar®); Group 2 (Lens) analyzed the axial thickness of the lens (UBM and Lenstar®). Based on standard ultrasonic speed from USP (1640 m/s) and UBM (1548 m/s), we calculated the real sound propagation speed in each tissue. Results: Based on USP, the corneal sound speed on control group (1616 m/s) was faster than on keratoconus group (1547 m/s) (P < 0.0001). Based on UBM, the lens sound speed on cataract group (1664 m/s) was faster that on control group (1605 m/s) (P < 0.0001). Discussion: It is known that sound propagates faster in materials with lower elasticity. We found that the sound speed on keratoconic corneas (high elasticity) was slower and on cataract lens (lower elasticity) was faster than normal corneas and lens in vivo.

  17. Detecting Temporal Change in Dynamic Sounds: On the Role of Stimulus Duration, Speed, and Emotion

    PubMed Central

    Schirmer, Annett; Escoffier, Nicolas; Cheng, Xiaoqin; Feng, Yenju; Penney, Trevor B.

    2016-01-01

    For dynamic sounds, such as vocal expressions, duration often varies alongside speed. Compared to longer sounds, shorter sounds unfold more quickly. Here, we asked whether listeners implicitly use this confound when representing temporal regularities in their environment. In addition, we explored the role of emotions in this process. Using a mismatch negativity (MMN) paradigm, we asked participants to watch a silent movie while passively listening to a stream of task-irrelevant sounds. In Experiment 1, one surprised and one neutral vocalization were compressed and stretched to create stimuli of 378 and 600 ms duration. Stimuli were presented in four blocks, two of which used surprised and two of which used neutral expressions. In one surprised and one neutral block, short and long stimuli served as standards and deviants, respectively. In the other two blocks, the assignment of standards and deviants was reversed. We observed a climbing MMN-like negativity shortly after deviant onset, which suggests that listeners implicitly track sound speed and detect speed changes. Additionally, this MMN-like effect emerged earlier and was larger for long than short deviants, suggesting greater sensitivity to duration increments or slowing down than to decrements or speeding up. Last, deviance detection was facilitated in surprised relative to neutral blocks, indicating that emotion enhances temporal processing. Experiment 2 was comparable to Experiment 1 with the exception that sounds were spectrally rotated to remove vocal emotional content. This abolished the emotional processing benefit, but preserved the other effects. Together, these results provide insights into listener sensitivity to sound speed and raise the possibility that speed biases duration judgements implicitly in a feed-forward manner. Moreover, this bias may be amplified for duration increments relative to decrements and within an emotional relative to a neutral stimulus context. PMID:26793161

  18. Laryngeal High-Speed Videoendoscopy: Rationale and Recommendation for Accurate and Consistent Terminology

    PubMed Central

    Deliyski, Dimitar D.; Hillman, Robert E.

    2015-01-01

    Purpose The authors discuss the rationale behind the term laryngeal high-speed videoendoscopy to describe the application of high-speed endoscopic imaging techniques to the visualization of vocal fold vibration. Method Commentary on the advantages of using accurate and consistent terminology in the field of voice research is provided. Specific justification is described for each component of the term high-speed videoendoscopy, which is compared and contrasted with alternative terminologies in the literature. Results In addition to the ubiquitous high-speed descriptor, the term endoscopy is necessary to specify the appropriate imaging technology and distinguish among modalities such as ultrasound, magnetic resonance imaging, and nonendoscopic optical imaging. Furthermore, the term video critically indicates the electronic recording of a sequence of optical still images representing scenes in motion, in contrast to strobed images using high-speed photography and non-optical high-speed magnetic resonance imaging. High-speed videoendoscopy thus concisely describes the technology and can be appended by the desired anatomical nomenclature such as laryngeal. Conclusions Laryngeal high-speed videoendoscopy strikes a balance between conciseness and specificity when referring to the typical high-speed imaging method performed on human participants. Guidance for the creation of future terminology provides clarity and context for current and future experiments and the dissemination of results among researchers. PMID:26375398

  19. Fast calibration of speed-of-sound using temperature prior in whole-body small animal optoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Mandal, Subhamoy; Nasonova, Elena; Deán-Ben, X. L.; Razansky, Daniel

    2015-03-01

    The speed of sound (SoS) in the imaged sample and in the coupling medium is an important parameter in optoacoustic tomography that must be specified in order to accurately restore maps of local optical absorbance. In this work, several hybrid focusing functions are described that successfully determine the most suitable SoS based on post-reconstruction images. The SoS in the coupling medium (water) can be determined from temperature readings. Thereby, this value is suggested to be used as an initial guess for faster SoS calibration in the reconstruction of tissues having a different SoS than water.

  20. A time-accurate implicit method for chemical non-equilibrium flows at all speeds

    NASA Technical Reports Server (NTRS)

    Shuen, Jian-Shun

    1992-01-01

    A new time accurate coupled solution procedure for solving the chemical non-equilibrium Navier-Stokes equations over a wide range of Mach numbers is described. The scheme is shown to be very efficient and robust for flows with velocities ranging from M less than or equal to 10(exp -10) to supersonic speeds.

  1. SOUND-SPEED INVERSION OF THE SUN USING A NONLOCAL STATISTICAL CONVECTION THEORY

    SciTech Connect

    Zhang Chunguang; Deng Licai; Xiong Darun; Christensen-Dalsgaard, Jorgen

    2012-11-01

    Helioseismic inversions reveal a major discrepancy in sound speed between the Sun and the standard solar model just below the base of the solar convection zone. We demonstrate that this discrepancy is caused by the inherent shortcomings of the local mixing-length theory adopted in the standard solar model. Using a self-consistent nonlocal convection theory, we construct an envelope model of the Sun for sound-speed inversion. Our solar model has a very smooth transition from the convective envelope to the radiative interior, and the convective energy flux changes sign crossing the boundaries of the convection zone. It shows evident improvement over the standard solar model, with a significant reduction in the discrepancy in sound speed between the Sun and local convection models.

  2. Effect of Disorder on Bulk Sound Wave Speed : A Multiscale Spectral Analysis.

    NASA Astrophysics Data System (ADS)

    Shrivastava, Rohit; Luding, Stefan

    2016-04-01

    Disorder in the form of size (polydispersity) and mass of discrete elements/particles in a disordered media (a granular matter like soil) have numerous effects on it's sound propagation characteristics [1,2]. The influence of disorder on the sound wave speed and it's frequency filtering characteristics is the subject of investigation. The study will assist in understanding the connection between particle-scale dynamics and system-scale behavior of wave propagation which can be further used for modeling during non-destructive testing, seismic exploration of buried objects (oil, mineral, etc.) or to study the internal structure of the Earth. Studying the wave propagation characteristics through Discrete Element Models with varying polydispersity and mass of discrete elements in real-time, frequency space as well as through dispersion curves (ω (frequency) v/s k (wavenumber)) can shed light on this aspect by providing better microscopic understanding. To isolate the P-wave from shear and rotational modes, a one-dimensional system of elements/particles is used to study the effect of mass disorder on bulk sound wave speed through ensemble averaging of signals. Increasing polydispersity/disorder decreases the sound wave speed because of decrease in the number of contacts between particles [2] but, in contrast, increasing mass disorder increases the sound wave speed (in 1 D chains). Thus we conclude that a competition exists between these two kinds of disorder for their influence on the bulk sound wave speed. References [1] Brian P. Lawney and Stefan Luding. Frequency filtering in disordered granular chains. Acta Mechanica, 225(8):2385-2407, 2014. [2] O. Mouraille and S. Luding. Sound wave propagation in weakly polydisperse granular materials. Ultrasonics, 48(6-7):498 - 505, 2008. Selected Papers from ICU 2007.

  3. Real-time sound speed correction using golden section search to enhance ultrasound imaging quality

    NASA Astrophysics Data System (ADS)

    Yoon, Chong Ook; Yoon, Changhan; Yoo, Yangmo; Song, Tai-Kyong; Chang, Jin Ho

    2013-03-01

    In medical ultrasound imaging, high-performance beamforming is important to enhance spatial and contrast resolutions. A modern receive dynamic beamfomer uses a constant sound speed that is typically assumed to 1540 m/s in generating receive focusing delays [1], [2]. However, this assumption leads to degradation of spatial and contrast resolutions particularly when imaging obese patients or breast since the sound speed is significantly lower than the assumed sound speed [3]; the true sound speed in the fatty tissue is around 1450 m/s. In our previous study, it was demonstrated that the modified nonlinear anisotropic diffusion is capable of determining an optimal sound speed and the proposed method is a useful tool to improve ultrasound image quality [4], [5]. In the previous study, however, we utilized at least 21 iterations to find an optimal sound speed, which may not be viable for real-time applications. In this paper, we demonstrates that the number of iterations can be dramatically reduced using the GSS(golden section search) method with a minimal error. To evaluate performances of the proposed method, in vitro experiments were conducted with a tissue mimicking phantom. To emulate a heterogeneous medium, the phantom was immersed in the water. From the experiments, the number of iterations was reduced from 21 to 7 with GSS method and the maximum error of the lateral resolution between direct and GSS was less than 1%. These results indicate that the proposed method can be implemented in real time to improve the image quality in the medical ultrasound imaging.

  4. Transcranial ultrasound imaging with speed of sound-based phase correction: a numerical study.

    PubMed

    Wang, Tianren; Jing, Yun

    2013-10-07

    This paper presents a numerical study for ultrasound transcranial imaging. To correct for the phase aberration from the skull, two critical steps are needed prior to brain imaging. In the first step, the skull shape and speed of sound are acquired by either CT scans or ultrasound scans. In the ultrasound scan approach, phased array and double focusing technique are utilized, which are able to estimate the thickness of the skull with a maximum error of around 10% and the average speed of sound in the skull is underestimated by less than 2%. In the second step, the fast marching method is used to compute the phase delay based on the known skull shape and sound speed from the first step, and the computation can be completed in seconds for 2D problems. The computed phase delays are then used in combination with the conventional delay-and-sum algorithm for generating B-mode images. Images of wire phantoms with CT or ultrasound scan-based phase correction are shown to have much less artifact than the ones without correction. Errors of deducing speed of sound from CT scans are also discussed regarding its effect on the transcranial ultrasound images. Assuming the speed of sound grows linearly with the density, this study shows that, the CT-based phase correction approach can provide clear images of wire phantoms even if the speed of sound is overestimated by 400 m s(-1), or the linear coefficient is overestimated by 40%. While in this study, ultrasound scan-based phase correction performs almost equally well with the CT-based approach, potential problems are identified and discussed.

  5. Range-Depth Tracking of Sounds from a Single-Point Deployment by Exploiting the Deep-Water Sound Speed Minimum

    DTIC Science & Technology

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Range-Depth Tracking of Sounds from a Single-Point...Deployment by Exploiting the Deep-Water Sound Speed Minimum Aaron Thode Scripps Institution of Oceanography University of California San Diego phone...mammal sounds in range and depth from a single mooring or platform (e.g. glider), by exploiting the propagation effects of the deep-water sound

  6. Temperature rule for the speed of sound in water: a chemical kinetics model

    PubMed

    Okazaki

    2000-09-15

    Water forms three-dimensional polymeric structures due to the influence of hydrogen bonds and is fundamentally different from other substances. One of the simplest ways to analyze the structure of water in any system, such as hydration, is to measure the degree of compressibility, which can be determined from the speed of sound, by making use of the physical laws established by Newton and later perfected by Laplace. Although the speed of sound is strongly dependent on the temperature of a liquid, Laplace's equation does not refer to temperature in any of its terms. It is necessary, therefore, to determine the degree of temperature dependency. However, only approximate expressions of a fifth-order polynomial have been reported so far in the literature. In this paper, a universal method for describing the speed of sound from the perspective of physicochemical reaction kinetics is presented. It is shown that the speed of sound U [ms(-1)] changes with temperature T [K] according to a thermodynamically-derived formula given as U= exp(-A/T-BlnT+C) and that the motion and propagation phenomena of sound energy can also be regarded as chemical reactions.

  7. Sound from a Two-Blade Propeller at Supersonic Tip Speeds

    NASA Technical Reports Server (NTRS)

    Hubbard, Harvey H; Lassiter, Leslie W

    1952-01-01

    Report presents the results of sound measurements at static conditions made for a two-blade 47-inch-diameter propeller in the tip Mach number range 0.75 to 1.30. For comparison, spectrums have been obtained at both subsonic and supersonic tip speeds. In addition, the measured data are compared with calculations by the theory of Gutin which has previously been found adequate for predicting the sound at subsonic tip speeds. Curves are presented from which the maximum over-all noise levels in free space may be estimated if the power, tip Mach number, and distance are known.

  8. Stochastic Estimation Applied to the Land Speed of Sound Record Attempt by a Rocket Car.

    DTIC Science & Technology

    1983-12-01

    STOCHASTIC ESTIMATION APPLIED TO THE LAND SPEED OF SOUND RECORD ATTEMPT BY A ROCKET CAR THESIS David A. Reinholz Captain, USAF 0.-- AFIT/GAE/AA/83DZ24 I...ESTIMATION APPLIED TO THE LAND SPEED OF SOUND RECORD ATTEMPT BY A ROCKET CAR THESIS Presented to the Faculty of the School of Engineering of the Air Force...first to interest me in the Budweiser Rocket Car and helped provide guidance throughout my work. The person with the most "corporate knowledge" about

  9. Preliminary mapping of void fractions and sound speeds in gassy marine sediments from subbottom profiles.

    PubMed

    Leighton, T G; Robb, G B N

    2008-11-01

    Bubbles of gas (usually methane) in marine sediments affect the load-bearing properties of the seabed and act as a natural reservoir of "greenhouse" gas. This paper describes a simple method which can be applied to historical and future subbottom profiles to infer bubble void fractions and map the vertical and horizontal distributions of gassy sediments, and the associated sound speed perturbations, even with single-frequency insonification. It operates by identifying horizontal features in the geology and interpreting any perceived change of depth in these as a bubble-mediated change in sound speed.

  10. The low-frequency sound speed of fluid-like gas-bearing sediments.

    PubMed

    Wilson, Preston S; Reed, Allen H; Wood, Warren T; Roy, Ronald A

    2008-04-01

    The low-frequency sound speed in a fluid-like kaolinite sediment containing air bubbles was measured using an acoustic resonator technique and found to be 114 ms with negligible dispersion between 100 and 400 Hz. The sediment's void fraction and bubble size distribution was determined from volumetric images obtained from x-ray computed tomography scans. A simplified version of Wood's effective medium model, which is dependent only upon the ambient pressure, the void fraction, the sediment's bulk mass density, and the assumption that all the bubbles are smaller than resonance size at the highest frequency of interest, described the measured sound speed.

  11. Site dependence of thickness and speed of sound in articular cartilage of bovine patella.

    PubMed

    Patil, S G; Zheng, Y P; Chen, Xin

    2010-08-01

    Researchers have made efforts to quantify thickness of articular cartilage as well as its acoustic and mechanical properties using various ultrasound (US) techniques during the last decades, because they are important indicators of articular cartilage degeneration. However, the variation of the thickness and speed of sound of articular cartilage at different anatomical sites would result in the uncertainty of US assessment of degeneration. In this paper, the site dependences of speed of sound and thickness of bovine patellar articular cartilage (n = 10) were investigated using a custom-made US measurement system. The thickness and speed of sound of articular cartilage at different locations of the bovine patella were measured on excised specimens ex situ using a noncontact US approach. A total of 10 patellae were tested. The results showed the overall mean value of the speed of sound in the articular cartilage at the 25 measured sites was 1626 +/- 86 m/s (range, 1507 to 1834 m/s). No statistically significant difference in the speed of sound was observed among the 25 locations or among the four quadrants of the patella. The highest speed of sound (1834 +/- 74 m/s) was obtained at the medial-upper quadrant and the lowest value (1507 +/- 74 m/s) at the medial-lower quadrant. Further grouping of the data revealed that the speed of sound in the central region (1633 +/- 21 m/s) was significantly (p < 0.01) larger than that for the surrounding region (1621 +/- 22 m/s). The overall mean thickness of the patellar articular cartilage was 1.34 +/- 0.34 mm. No significant difference was obtained in the thickness among the 25 locations and also among the four quadrants. However, when the thickness values were divided diagonally, a significant difference (p < 0.01) was observed between the upper region (1.27 +/- 0.11 mm) and the lower region (1.31 +/- 0.41 mm) of the patellae. Although no significant differences in the thickness and speed of sound among the tested sites were

  12. Device for precision measurement of speed of sound in a gas

    DOEpatents

    Kelner, Eric; Minachi, Ali; Owen, Thomas E.; Burzynski, Jr., Marion; Petullo, Steven P.

    2004-11-30

    A sensor for measuring the speed of sound in a gas. The sensor has a helical coil, through which the gas flows before entering an inner chamber. Flow through the coil brings the gas into thermal equilibrium with the test chamber body. After the gas enters the chamber, a transducer produces an ultrasonic pulse, which is reflected from each of two faces of a target. The time difference between the two reflected signals is used to determine the speed of sound in the gas.

  13. Inference of optimal speed for sound centrifugal casting of Al-12Si alloys

    NASA Astrophysics Data System (ADS)

    Agari, Shailesh Rao; Mukunda, P. G.; Rao, Shrikantha S.; Sudhakar, K. G.

    2011-05-01

    True centrifugal casting is a standard casting technique for the manufacture of hollow, intricate and sound castings without the use of cores. The molten metal or alloy poured into the rotating mold forms a hollow casting as the centrifugal forces lift the liquid along the mold inner surface. When a mold is rotated at low and very high speeds defects are found in the final castings. Obtaining the critical speed for sound castings should not be a matter of guess or based on experience. The defects in the casting are mainly due to the behavior of the molten metal during the teeming and solidification process. Motion of molten metal at various speeds and its effect during casting are addressed in this paper. Eutectic Al-12Si alloy is taken as an experiment fluid and its performance during various rotational speeds is discussed.

  14. A model for the vertical sound speed and absorption profiles in Titan's atmosphere based on Cassini-Huygens data.

    PubMed

    Petculescu, Andi; Achi, Peter

    2012-05-01

    Measurements of thermodynamic quantities in Titan's atmosphere during the descent of Huygens in 2005 are used to predict the vertical profiles for the speed and intrinsic attenuation (or absorption) of sound. The calculations are done using one author's previous model modified to accommodate non-ideal equations of state. The vertical temperature profile places the tropopause about 40 km above the surface. In the model, a binary nitrogen-methane composition is assumed for Titan's atmosphere, quantified by the methane fraction measured by the gas chromatograph/mass spectrometer (GCMS) onboard Huygens. To more accurately constrain the acoustic wave number, the variation of thermophysical properties (specific heats, viscosity, and thermal conductivity) with altitude is included via data extracted from the NIST Chemistry WebBook [URL webbook.nist.gov, National Institute of Standards and Technology Chemistry WebBook (Last accessed 10/20/2011)]. The predicted speed of sound profile fits well inside the spread of the data recorded by Huygens' active acoustic sensor. In the N(2)-dominated atmosphere, the sound waves have negligible relaxational dispersion and mostly classical (thermo-viscous) absorption. The cold and dense environment of Titan can sustain acoustic waves over large distances with relatively small transmission losses, as evidenced by the small absorption. A ray-tracing program is used to assess the bounds imposed by the zonal wind-measured by the Doppler Wind Experiment on Huygens-on long-range propagation.

  15. The influence of sea ice, wind speed and marine mammals on Southern Ocean ambient sound.

    PubMed

    Menze, Sebastian; Zitterbart, Daniel P; van Opzeeland, Ilse; Boebel, Olaf

    2017-01-01

    This paper describes the natural variability of ambient sound in the Southern Ocean, an acoustically pristine marine mammal habitat. Over a 3-year period, two autonomous recorders were moored along the Greenwich meridian to collect underwater passive acoustic data. Ambient sound levels were strongly affected by the annual variation of the sea-ice cover, which decouples local wind speed and sound levels during austral winter. With increasing sea-ice concentration, area and thickness, sound levels decreased while the contribution of distant sources increased. Marine mammal sounds formed a substantial part of the overall acoustic environment, comprising calls produced by Antarctic blue whales (Balaenoptera musculus intermedia), fin whales (Balaenoptera physalus), Antarctic minke whales (Balaenoptera bonaerensis) and leopard seals (Hydrurga leptonyx). The combined sound energy of a group or population vocalizing during extended periods contributed species-specific peaks to the ambient sound spectra. The temporal and spatial variation in the contribution of marine mammals to ambient sound suggests annual patterns in migration and behaviour. The Antarctic blue and fin whale contributions were loudest in austral autumn, whereas the Antarctic minke whale contribution was loudest during austral winter and repeatedly showed a diel pattern that coincided with the diel vertical migration of zooplankton.

  16. The influence of sea ice, wind speed and marine mammals on Southern Ocean ambient sound

    PubMed Central

    van Opzeeland, Ilse; Boebel, Olaf

    2017-01-01

    This paper describes the natural variability of ambient sound in the Southern Ocean, an acoustically pristine marine mammal habitat. Over a 3-year period, two autonomous recorders were moored along the Greenwich meridian to collect underwater passive acoustic data. Ambient sound levels were strongly affected by the annual variation of the sea-ice cover, which decouples local wind speed and sound levels during austral winter. With increasing sea-ice concentration, area and thickness, sound levels decreased while the contribution of distant sources increased. Marine mammal sounds formed a substantial part of the overall acoustic environment, comprising calls produced by Antarctic blue whales (Balaenoptera musculus intermedia), fin whales (Balaenoptera physalus), Antarctic minke whales (Balaenoptera bonaerensis) and leopard seals (Hydrurga leptonyx). The combined sound energy of a group or population vocalizing during extended periods contributed species-specific peaks to the ambient sound spectra. The temporal and spatial variation in the contribution of marine mammals to ambient sound suggests annual patterns in migration and behaviour. The Antarctic blue and fin whale contributions were loudest in austral autumn, whereas the Antarctic minke whale contribution was loudest during austral winter and repeatedly showed a diel pattern that coincided with the diel vertical migration of zooplankton. PMID:28280544

  17. The influence of sea ice, wind speed and marine mammals on Southern Ocean ambient sound

    NASA Astrophysics Data System (ADS)

    Menze, Sebastian; Zitterbart, Daniel P.; van Opzeeland, Ilse; Boebel, Olaf

    2017-01-01

    This paper describes the natural variability of ambient sound in the Southern Ocean, an acoustically pristine marine mammal habitat. Over a 3-year period, two autonomous recorders were moored along the Greenwich meridian to collect underwater passive acoustic data. Ambient sound levels were strongly affected by the annual variation of the sea-ice cover, which decouples local wind speed and sound levels during austral winter. With increasing sea-ice concentration, area and thickness, sound levels decreased while the contribution of distant sources increased. Marine mammal sounds formed a substantial part of the overall acoustic environment, comprising calls produced by Antarctic blue whales (Balaenoptera musculus intermedia), fin whales (Balaenoptera physalus), Antarctic minke whales (Balaenoptera bonaerensis) and leopard seals (Hydrurga leptonyx). The combined sound energy of a group or population vocalizing during extended periods contributed species-specific peaks to the ambient sound spectra. The temporal and spatial variation in the contribution of marine mammals to ambient sound suggests annual patterns in migration and behaviour. The Antarctic blue and fin whale contributions were loudest in austral autumn, whereas the Antarctic minke whale contribution was loudest during austral winter and repeatedly showed a diel pattern that coincided with the diel vertical migration of zooplankton.

  18. Can the speed of sound be used for detecting critical states of fluid mixtures?

    PubMed

    Reis, João Carlos R; Ribeiro, Nuno; Aguiar-Ricardo, Ana

    2006-01-12

    The phenomenology of sound speeds in fluid mixtures is examined near and across critical lines. Using literature data for binary and ternary mixtures, it is shown that the ultrasound speed along an isotherm-isopleth passes through a minimum value in the form of an angular (or V-shaped) point at critical states. The relation between critical and pseudo-critical coordinates is discussed. For nonazeotropic fixed-composition fluid mixtures, pseudo-critical temperatures and pressures are found to be lower than the corresponding critical temperatures and pressures. The analysis shows that unstable pseudo-critical states cannot be detected using acoustic methods. The thermodynamic link between sound speeds and isochoric heat capacities is formulated and discussed in terms of p-Vm-T derivatives capable of being calculated using cubic equations of state. Based on the Griffiths-Wheeler theory of critical phenomena, a new specific link between critical sound speeds and critical isochoric heat capacities is deduced in terms of the rate of change of critical pressures and critical temperatures along the p-T projection of the critical locus of binary fluid mixtures. It is shown that the latter link can be used to obtain estimates of critical isochoric heat capacities from the experimental determination of critical speeds of sound. The applicability domain of the new link does not include binary systems at compositions along the critical line for which the rate of change in pressure with temperature changes sign. The new equation is combined with thermodynamic data to provide approximate numerical estimates for the speed of sound in two mixtures of carbon dioxide and ethane at different temperatures along their critical isochores. A clear decrease in the sound speed is found at critical points. A similar behavior is suggested by available critical heat capacity data for several binary fluid mixtures. Using an acoustic technique, the critical temperature and pressure were

  19. Multi-frequency characterization of speed of sound for longitudinal transmission on freshly excised human skulls

    NASA Astrophysics Data System (ADS)

    Pichardo, Samuel; Hynynen, Kullervo

    2010-03-01

    The results of measurements of longitudinal speed of sound are presented for seven specimens of human calvaria. The study was done for frequencies between 0.27 and 2.525 MHz. Specimens were obtained from fresh cadavers through a protocol with the Division of Anatomy of the University of Toronto. The specimens were mounted in polycarbonate frames that were marked for stereoscopic positioning. CT scans of the skulls mounted on their frames were performed and a three-dimensional reconstruction of the skull surface was done. A positioning system ensured normal sound incidence of an acoustic signal produced by a focused device with a diameter of 5 cm and a focal length of 10 cm. Speed of sound estimation was done with measurements of time-of-flight using a needle hydrophone (diameter of 0.5 mm) and a sound propagation model through layers that takes into account change of speed of sound in function of density. For six of seven specimens, measurements were done on five locations on the calvaria and for the other specimen three measurements were done. In total, measurements were done on thirty-three locations. Results showed that the average (±s.d.) of the speed of sound was 2265(±202), 2360(±207), 2317(±283), 2309(±248) and 2080(±148) mṡs-1 for frequencies of 0.27, 0.836, 1.402, 1.965 and 2.525 MHz, respectively. Dispersion effects were observed at individual basis per specimen, which were detected for the six of specimens as in increase in the speed sound when frequency went from 0.27 to 0.836 MHz. However, this increase was only statistically significant (p-value⩽0.05) for two specimens, with a maximal increase of +152 mṡs-1. A decrease in the speed of sound was also observed for four specimens when the frequency reached the highest values but it was statistically significant only for one of them (p = 0.03), with a decrease of -229 mṡs-1.

  20. Time-angle sensitivity kernels for sound-speed perturbations in a shallow ocean.

    PubMed

    Aulanier, Florian; Nicolas, Barbara; Roux, Philippe; Mars, Jérôme I

    2013-07-01

    Acoustic waves traveling in a shallow-water waveguide produce a set of multiple paths that can be characterized as a geometric approximation by their travel time (TT), direction of arrival (DOA), and direction of departure (DOD). This study introduces the use of the DOA and DOD as additional observables that can be combined to the classical TT to track sound-speed perturbations in an oceanic waveguide. To model the TT, DOA, and DOD variations induced by sound-speed perturbations, the three following steps are used: (1) In the first-order Born approximation, the Fréchet kernel provides a linear link between the signal fluctuations and the sound-speed perturbations; (2) a double-beamforming algorithm is used to transform the signal fluctuations received on two source-receiver arrays in the time, receiver-depth, and source-depth domain into the eigenray equivalent measured in the time, reception-angle and launch angle domain; and finally (3) the TT, DOA, and DOD variations are extracted from the double-beamformed signal variations through a first-order Taylor development. As a result, time-angle sensitivity kernels are defined and used to build a linear relationship between the observable variations and the sound-speed perturbations. This approach is validated with parabolic-equation simulations in a shallow-water ocean context.

  1. Smartphone-aided measurements of the speed of sound in different gaseous mixtures

    NASA Astrophysics Data System (ADS)

    Parolin, Sara Orsola; Pezzi, Giovanni

    2013-11-01

    Here we describe classroom-based procedures aiming at the estimation of the speed of sound in different gas mixtures with the help of a plastic drain pipe and two iPhones or iPod touches. The procedures were conceived to be performed with simple and readily available tools.

  2. Comments on "Speed of Sound in Metal Pipes: An Inexpensive Lab"

    ERIC Educational Resources Information Center

    Blodgett, Earl D.

    2009-01-01

    In a recent article Huggins outlines a very simple method of measuring the speed of sound in metal pipes by striking one end with a hammer and recording the transit time as the resultant pulse echoes back and forth. We immediately adapted this for use in an introductory laboratory where we are familiarizing students with the measurement of…

  3. An Undergraduate Experiment for the Measurement of the Speed of Sound in Air: Phenomena and Discussion

    ERIC Educational Resources Information Center

    Yang, Hujiang; Zhao, Xiaohong; Wang, Xin; Xiao, Jinghua

    2012-01-01

    In this paper, we present and discuss some phenomena in an undergraduate experiment for the measurement of the speed of sound in air. A square wave distorts when connected to a piezoelectric transducer. Moreover, the amplitude of the receiving signal varies with the driving frequency. Comparing with the Gibbs phenomenon, these phenomena can be…

  4. Smartphone-Aided Measurements of the Speed of Sound in Different Gaseous Mixtures

    ERIC Educational Resources Information Center

    Parolin, Sara Orsola; Pezzi, Giovanni

    2013-01-01

    Here we describe classroom-based procedures aiming at the estimation of the speed of sound in different gas mixtures with the help of a plastic drain pipe and two iPhones or iPod touches. The procedures were conceived to be performed with simple and readily available tools.

  5. How speed-of-sound measurements could bring constraints on the composition of Titan's seas

    NASA Astrophysics Data System (ADS)

    Cordier, D.

    2016-06-01

    The hydrocarbon seas of Titan, discovered by the Cassini/Huygens mission are among the most mysterious and interesting features of this moon. In the future, a possible dedicated planetary probe will certainly measure the speed of sound in this cryogenic liquid, as was planned in the case of Huygens landing in a sea. Previous theoretical studies of such acoustic measurements were based on simple models, leading in some cases to unphysical situations. Employed in a vast body of chemical engineering works, the state-of-the-art perturbed-chain statistical associating fluid theory (PC-SAFT) model has been recently introduced in studies aimed at Titan. Here, I revisit the issue of the speed of sound in Titan's liquids, in light of this theory. I describe, in detail, the derivation of the speed of sound from the chosen equation of state and the potential limitations of the approach. To make estimations of the composition of a ternary liquid mixture N2:CH4:C2H6 from speed-of-sound measurements an original inversion algorithm is proposed. It is shown that 50 measures between 90 and 100 K are enough to ensure an accuracy of the derived compositions of better than 10 per cent. The influence of the possible presence of propane is also investigated.

  6. The Equation of State and The Speed of Sound On Lake Baikal

    NASA Astrophysics Data System (ADS)

    Sherstyankin, P. P.; Ivanov, V. G.; Ras, V. V. Blinov Lin Sb

    Usually as an equation for Baikal water state is used in the form (Chen, Millero 1986), which correlates with important effects connected with the temperature of maximal density (Sherstyankin, Kuimova, Potemkin 2000). However any experimental proofs of applicability of such equation of a status of the Baikal waters was not. It became possible at comparison of values of speed of a sound designed for the Baikal waters at use of the equation of a state in the form Chen-Millero, with values of speed of a sound determined experimentally Chenskii et al. (1998) and which the equations of a state of water are caused real, but unknown. The speeds of a sound with applica- tion of the equation of a state in the form Chen-Millero were designed by two ways: under the formula in the form Chen, Millero (1986) and on adiabatic and isothermal compressibilities (Sherstyankin et al. 2002, in press). The values of speed of a sound designed by both ways, have appeared little bit more (circa 0.2 m/s) experimental val- ues (absolute mistake +/- 0.2 m/s, Chenskii at al. 1986). The equation of a state for Baikal waters, taken in the form (Chen, Millero 1986), a little bit differs from real and can be used for practical purposes. The work is supported by the grants RFBR No.01-05-65097 and No.01-05-97229.

  7. Observations of sound-speed fluctuations in the western Philippine Sea in the spring of 2009.

    PubMed

    Colosi, John A; Van Uffelen, Lora J; Cornuelle, Bruce D; Dzieciuch, Matthew A; Worcester, Peter F; Dushaw, Brian D; Ramp, Steven R

    2013-10-01

    As an aid to understanding long-range acoustic propagation in the Philippine Sea, statistical and phenomenological descriptions of sound-speed variations were developed. Two moorings of oceanographic sensors located in the western Philippine Sea in the spring of 2009 were used to track constant potential-density surfaces (isopycnals) and constant potential-temperature surfaces (isotherms) in the depth range 120-2000 m. The vertical displacements of these surfaces are used to estimate sound-speed fluctuations from internal waves, while temperature/salinity variability along isopycnals are used to estimate sound-speed fluctuations from intrusive structure often termed spice. Frequency spectra and vertical covariance functions are used to describe the space-time scales of the displacements and spiciness. Internal-wave contributions from diurnal and semi-diurnal internal tides and the diffuse internal-wave field [related to the Garrett-Munk (GM) spectrum] are found to dominate the sound-speed variability. Spice fluctuations are weak in comparison. The internal wave and spice frequency spectra have similar form in the upper ocean but are markedly different below 170-m depth. Diffuse internal-wave mode spectra show a form similar to the GM model, while internal-tide mode spectra scale as mode number to the minus two power. Spice decorrelates rapidly with depth, with a typical correlation scale of tens of meters.

  8. Time-of-Flight Measurement of the Speed of Sound in a Metal Bar

    ERIC Educational Resources Information Center

    Ganci, Salvatore

    2016-01-01

    A simple setup was designed for a "time-of-flight" measurement of the sound speed in a metal bar. The experiment requires low cost components and is very simple to understand by students. A good use of it is as a demonstration experiment.

  9. Time-of-Flight Measurement of the Speed of Sound in Water

    ERIC Educational Resources Information Center

    Ganci, Salvatore

    2016-01-01

    A simple setup is designed to investigate a "time-of-flight" measurement of the speed of sound in water. This experiment only requires low cost components and is also very simple to understand by students. It could be easily used as a demonstration experiment.

  10. Detecting interferences with iOS applications to measure speed of sound

    NASA Astrophysics Data System (ADS)

    Yavuz, Ahmet; Kağan Temiz, Burak

    2016-01-01

    Traditional experiments measuring the speed of sound consist of studying harmonics by changing the length of a glass tube closed at one end. In these experiments, the sound source and observer are outside of the tube. In this paper, we propose the modification of this old experiment by studying destructive interference in a pipe using a headset, iPhone and iPad. The iPhone is used as an emitter with signal generator application and the iPad is used as the receiver with a spectrogram application. Two experiments are carried out for measures: the emitter inside of the tube with the receiver outside, and vice versa. We conclude that it is even possible to adequately and easily measure the speed of sound using a cup or a can of coke with the method described in this paper.

  11. Photoacoustically Measured Speeds of Sound and the Equation of State of HBO2: On Understanding Detonation with Boron Fuel

    SciTech Connect

    Zaug, J M; Bastea, S; Crowhurst, J; Armstrong, M; Fried, L; Teslich, N

    2010-03-09

    Elucidation of geodynamic, geochemical, and shock induced processes is limited by challenges to accurately determine molecular fluid equations of state (EOS). High pressure liquid state reactions of carbon species underlie physiochemical mechanisms such as differentiation of planetary interiors, deep carbon sequestration, propellant deflagration, and shock chemistry. In this proceedings paper we introduce a versatile photoacoustic technique developed to measure accurate and precise speeds of sound (SoS) of high pressure molecular fluids and fluid mixtures. SoS of an intermediate boron oxide, HBO{sub 2} are measured up to 0.5 GPa along the 277 C isotherm. A polarized exponential-6 interatomic potential form, parameterized using our SoS data, enables EOS determinations and corresponding semi-empirical evaluations of >2000 C thermodynamic states including energy release from bororganic formulations. Our thermochemical model propitiously predicts boronated hydrocarbon shock Hugoniot results.

  12. Statistical inference of seabed sound-speed structure in the Gulf of Oman Basin.

    PubMed

    Sagers, Jason D; Knobles, David P

    2014-06-01

    Addressed is the statistical inference of the sound-speed depth profile of a thick soft seabed from broadband sound propagation data recorded in the Gulf of Oman Basin in 1977. The acoustic data are in the form of time series signals recorded on a sparse vertical line array and generated by explosive sources deployed along a 280 km track. The acoustic data offer a unique opportunity to study a deep-water bottom-limited thickly sedimented environment because of the large number of time series measurements, very low seabed attenuation, and auxiliary measurements. A maximum entropy method is employed to obtain a conditional posterior probability distribution (PPD) for the sound-speed ratio and the near-surface sound-speed gradient. The multiple data samples allow for a determination of the average error constraint value required to uniquely specify the PPD for each data sample. Two complicating features of the statistical inference study are addressed: (1) the need to develop an error function that can both utilize the measured multipath arrival structure and mitigate the effects of data errors and (2) the effect of small bathymetric slopes on the structure of the bottom interacting arrivals.

  13. Monitoring of variations in the speed of sound in contracting and relaxing muscle

    NASA Astrophysics Data System (ADS)

    Hossain, M. Zakir; Voigt, Horst; Grill, Wolfgang

    2009-03-01

    Beside of changes in the shape of contracting and relaxing muscle, which can be monitored with ultrasound, also changes in the velocity of ultrasound are expected. To observe such changes with high resolution for the gastrocnemius muscle of athletes a novel detection scheme has been developed. As already introduced for the detection of sideways expansion of the muscle, ultrasonic transducers are mounted sideways on opposing positions of the skin. To detect variations of the speed of sound, the expansion of the muscle is suppressed by mechanical clamping. Under this condition, any variation in the time-of-flight of ultrasonic signals can only be introduced by a variation of the speed of sound along the path of the ultrasound transit signal. The observed rather small variations of the speed of sound are compared to the signals obtained by ultrasound monitoring for the extension and contraction observed for free sideways motion (unclamped muscle). Opposite to the general behavior of a free muscle the clamped muscle shows a diminishing time-of-flight under contraction relating to an increase in the sound velocity. Since clamping also reduces effects of inertia, the influence of inertia on muscle dynamics can be illustrated by comparison of measurements on clamped and free muscle.

  14. Determinants of the reliability of ultrasound tomography sound speed estimates as a surrogate for volumetric breast density

    SciTech Connect

    Khodr, Zeina G.; Pfeiffer, Ruth M.; Gierach, Gretchen L.; Sak, Mark A.; Bey-Knight, Lisa; Duric, Nebojsa; Littrup, Peter; Ali, Haythem; Vallieres, Patricia; Sherman, Mark E.

    2015-10-15

    Purpose: High breast density, as measured by mammography, is associated with increased breast cancer risk, but standard methods of assessment have limitations including 2D representation of breast tissue, distortion due to breast compression, and use of ionizing radiation. Ultrasound tomography (UST) is a novel imaging method that averts these limitations and uses sound speed measures rather than x-ray imaging to estimate breast density. The authors evaluated the reproducibility of measures of speed of sound and changes in this parameter using UST. Methods: One experienced and five newly trained raters measured sound speed in serial UST scans for 22 women (two scans per person) to assess inter-rater reliability. Intrarater reliability was assessed for four raters. A random effects model was used to calculate the percent variation in sound speed and change in sound speed attributable to subject, scan, rater, and repeat reads. The authors estimated the intraclass correlation coefficients (ICCs) for these measures based on data from the authors’ experienced rater. Results: Median (range) time between baseline and follow-up UST scans was five (1–13) months. Contributions of factors to sound speed variance were differences between subjects (86.0%), baseline versus follow-up scans (7.5%), inter-rater evaluations (1.1%), and intrarater reproducibility (∼0%). When evaluating change in sound speed between scans, 2.7% and ∼0% of variation were attributed to inter- and intrarater variation, respectively. For the experienced rater’s repeat reads, agreement for sound speed was excellent (ICC = 93.4%) and for change in sound speed substantial (ICC = 70.4%), indicating very good reproducibility of these measures. Conclusions: UST provided highly reproducible sound speed measurements, which reflect breast density, suggesting that UST has utility in sensitively assessing change in density.

  15. Determinants of the reliability of ultrasound tomography sound speed estimates as a surrogate for volumetric breast density

    PubMed Central

    Khodr, Zeina G.; Sak, Mark A.; Pfeiffer, Ruth M.; Duric, Nebojsa; Littrup, Peter; Bey-Knight, Lisa; Ali, Haythem; Vallieres, Patricia; Sherman, Mark E.; Gierach, Gretchen L.

    2015-01-01

    Purpose: High breast density, as measured by mammography, is associated with increased breast cancer risk, but standard methods of assessment have limitations including 2D representation of breast tissue, distortion due to breast compression, and use of ionizing radiation. Ultrasound tomography (UST) is a novel imaging method that averts these limitations and uses sound speed measures rather than x-ray imaging to estimate breast density. The authors evaluated the reproducibility of measures of speed of sound and changes in this parameter using UST. Methods: One experienced and five newly trained raters measured sound speed in serial UST scans for 22 women (two scans per person) to assess inter-rater reliability. Intrarater reliability was assessed for four raters. A random effects model was used to calculate the percent variation in sound speed and change in sound speed attributable to subject, scan, rater, and repeat reads. The authors estimated the intraclass correlation coefficients (ICCs) for these measures based on data from the authors’ experienced rater. Results: Median (range) time between baseline and follow-up UST scans was five (1–13) months. Contributions of factors to sound speed variance were differences between subjects (86.0%), baseline versus follow-up scans (7.5%), inter-rater evaluations (1.1%), and intrarater reproducibility (∼0%). When evaluating change in sound speed between scans, 2.7% and ∼0% of variation were attributed to inter- and intrarater variation, respectively. For the experienced rater’s repeat reads, agreement for sound speed was excellent (ICC = 93.4%) and for change in sound speed substantial (ICC = 70.4%), indicating very good reproducibility of these measures. Conclusions: UST provided highly reproducible sound speed measurements, which reflect breast density, suggesting that UST has utility in sensitively assessing change in density. PMID:26429241

  16. Rapid and Accurate Calculation of a Speed Dependent Spectral Line Shape

    NASA Astrophysics Data System (ADS)

    Beverstock, D. Reed; Weaver, Kendra Letchworth; Benner, D. Chris

    2014-06-01

    Use of the Voigt profile with the Lorentz width allowed to vary with the speed of collision has been hampered by the lack of fast accurate algorithms. Such an algorithm has been written assuming a quadratic dependence of the Lorentz width upon the speed of collision that is accurate to one part in 10 000 and is generally only a factor of four or so slower than the equivalent Voigt calculation with the Letchworth and Benner algorithm. The only exception to the accuracy is far from line center near the Doppler limit when the speed dependent parameter is quite large. At this point the spectral line has fallen by at least 17 orders of magnitude from the line center and is generally insignificant. Gauss-Hermite quadrature of third to seventeenth order, Taylor series expansion about precomputed points and spline interpolation are used in the computation of both the real and imaginary parts for various regions. Kendra L. Letchworth and D. Chris Benner, JQSRT 107 (2007) 173-192. This work was funded by the Jet Propulsion Laboratory and National Science Foundation.

  17. Model intermolecular potentials and virial coefficients determined from the speed of sound

    NASA Astrophysics Data System (ADS)

    Trusler, J. P. M.; Wakeham, W. A.; Zarari, M. P.

    A simple procedure is given for determining model two- and three-body intermolecular potential energy functions from precise measurements of the speed of sound in the gas phase. The method is applied to the pure gases argon, methane and nitrogen and results are considered for propane and the mixture (methane + propane) obtained recently by similar methods. For the pair potential, the four-parameter model proposed by Maitland and Smith is used while the consequences of three-body forces were generally assumed to be represented adequately by the triple-dipole dispersion potential of Axilrod and Teller. The effect of including additional dispersion and exchange terms in the three-body potential was investigated for argon; each of these terms is significant but their effect on the third virial coefficient may be absorbed accurately in an effective triple-dipole potential. Three or, in some cases, all four of the parameters in the pair potential were optimized, together with the triple-dipole dispersion coefficient, in fits to the acoustic data. Ordinary second and third virial coefficients have been calculated from the model potential and the former are shown to be in excellent agreement with directly measured values. In the case of the third virial coefficient, some small discrepancies are noted; the resolution of these differences could have important implications for our understanding of many-body forces. The values of the dilute-gas viscosity predicted by the model pair potentials are examined also and, in the case of argon, found to be in good agreement with experimental values; for the other systems differences of several per cent were noted.

  18. Planck-scale-induced speed of sound in a trapped Bose-Einstein condensate

    NASA Astrophysics Data System (ADS)

    Castellanos, E.; Rivas, J. I.; Dominguez-Rocha, V.

    2014-06-01

    In the present work, we analyze the corrections caused by an anomalous dispersion relation, suggested in several quantum gravity models, upon the speed of sound in a weakly interacting Bose-Einstein condensate, trapped in a potential of the form V(r)\\sim r^{2} . We show that the corresponding ground-state energy and consequently, the associated speed of sound, present corrections with respect to the usual case, which may be used to explore the sensitivity to Planck-scale effects on these relevant properties associated with the condensate. Indeed, we stress that this type of macroscopic bodies may be more sensitive, under certain conditions, to Planck-scale manifestations than its constituents. In addition, we prove that the inclusion of a trapping potential, together with many-body contributions, improves the sensitivity to Planck-scale signals, compared to the homogeneous system.

  19. High precision, fast ultrasonic thermometer based on measurement of the speed of sound in air

    NASA Astrophysics Data System (ADS)

    Huang, K. N.; Huang, C. F.; Li, Y. C.; Young, M. S.

    2002-11-01

    This study presents a microcomputer-based ultrasonic system which measures air temperature by detecting variations in the speed of sound in the air. Changes in the speed of sound are detected by phase shift variations of a 40 kHz continuous ultrasonic wave. In a test embodiment, two 40 kHz ultrasonic transducers are set face to face at a constant distance. Phase angle differences between transmitted and received signals are determined by a FPGA digital phase detector and then analyzed in an 89C51 single-chip microcomputer. Temperature is calculated and then sent to a LCD display and, optionally, to a PC. Accuracy of measurement is within 0.05 degC at an inter-transducer distance of 10 cm. Temperature variations are displayed within 10 ms. The main advantages of the proposed system are high resolution, rapid temperature measurement, noncontact measurement and easy implementation.

  20. Vibrational behavior of a soundbox in an atmosphere with a variable speed of sound.

    PubMed

    Chen, Mo; Kotlicki, Andrzej; Waltham, Chris; Wolfe, Nathan; Yu, Jing Fei; Zhu, Chenchong

    2012-03-01

    This paper describes a semi-quantitative method, suitable for a student laboratory exercise that shows that the acoustic properties of the soundbox of a musical instrument depend on the sound speed of the atmosphere surrounding and filling the instrument. A gas tent was constructed and used to enclose instruments in helium, carbon dioxide and mixtures thereof, allowing the sound speed to be varied from 250 to 1000 m/s. Soundboard admittance data were taken using a guitar and a violin as examples. The data, expressed as contour plots, show clearly the qualitative relationship between air and wood modes, and the guitar data are compared with a simple mechanical model. Experimental details of the construction and operation of gas tent are given, with attention paid to safety issues.

  1. 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.

  2. Adiabatic and entropy decomposition in P (ϕI, XI J) theories with multiple sound speeds

    NASA Astrophysics Data System (ADS)

    Longden, Chris

    2017-01-01

    We consider P (ϕI,XI J) theories of multifield inflation and ask the question of how to define the adiabatic and entropy perturbations, widely used in calculating the curvature and isocurvature power spectra, in this general context. It is found that when the field perturbations propagate with different speeds, these adiabatic and entropy modes are not generally the fundamental (most natural to canonically quantize) degrees of freedom that propagate with a single speed. The alternative fields which do propagate with a single speed are found to be a rotation in field space of the adiabatic and entropy perturbations. We show how this affects the form of the horizon-crossing power spectrum, when there is not a single "adiabatic sound speed" sourcing the curvature perturbation. Special cases of our results are discussed, including P (X ) theories where the adiabatic and entropy perturbations are fundamental. We finally look at physical motivations for considering multispeed models of inflation, particularly showing that disformal couplings can naturally lead to the kind of kinetic interactions which cause fields to have different sound speeds.

  3. Adaptive wall technology for three-dimensional models at high subsonic speeds and aerofoil testing through the speed of sound

    NASA Technical Reports Server (NTRS)

    Lewis, M. C.; Taylor, N. J.; Goodyer, M. J.

    1992-01-01

    Adaptive wall research at the University of Southampton has been directed towards the development of testing techniques for use in nonporous test sections where two flexible walls are profiled in single curvature. This paper highlights the recent advances that have been made in the testing of 2D airfoils through the speed of sound and the testing of 3D models at high subsonic speeds. Techniques have been developed to accommodate the variety of flow regimes encountered in near sonic airfoil tests. The experimental evidence to date suggests that the new techniques coupled with established procedures allow airfoil data, free from top and bottom wall interference, to be gathered from adaptive flexible walled test sections throughout the entire subsonic, transonic and supersonic speed ranges. Techniques applicable to the testing of 3D models have evolved primarily from experience gained by testing sidewall mounted half-wings. Emphasis has been placed upon models with planforms similar to those of current transport wings. Techniques for high subsonic speeds have now been developed to the point where the residual levels of interference are low.

  4. Gas Nonideality at One Atmosphere Revealed through Speed of Sound Measurements and Heat Capacity Determinations

    ERIC Educational Resources Information Center

    Halpern, Arthur M.; Liu, Allen

    2008-01-01

    Using an easy-to-make cylindrical resonator, students can measure the speed of sound in a gas, u, with sufficiently high precision (by locating standing-wave Lissajous patterns on an oscilloscope) to observe real gas properties at one atmosphere and 300 K. For CO[subscript 2] and SF[subscript 6], u is found to be 268.83 and 135.25 m s[superscript…

  5. Speed of Sound versus Temperature Using PVC Pipes Open at Both Ends

    ERIC Educational Resources Information Center

    Bacon, Michael E.

    2012-01-01

    In this paper we investigate the speed of sound in air as a function of temperature using a simple and inexpensive apparatus. For this experiment it is essential that the appropriate end corrections be taken into account. In a recent paper the end corrections for 2-in i.d. (5.04-cm) PVC pipes open at both ends were investigated. The air column…

  6. Thermodynamic properties of nitrogen gas derived from measurements of sound speed. [for cryogenic wind tunnels

    NASA Technical Reports Server (NTRS)

    Younglove, B.; Mccarty, R. D.

    1979-01-01

    A virial equation of state for nitrogen was determined by use of newly measured speed-of-sound data and existing pressure-density-temperature data in a multiproperty-fitting technique. The experimental data taken were chosen to optimize the equation of state for a pressure range of 0 to 10 atm and for a temperature range of 60 to 350 K. Comparisons are made for thermodynamic properties calculated both from the new equation and from existing equations of state.

  7. Simultaneous imaging of ultrasound attenuation, speed of sound, and optical absorption in a photoacoustic setup

    NASA Astrophysics Data System (ADS)

    Willemink, Rene G. H.; Manohar, Srirang; Jose, Jithin; Slump, Kees; van der Heijden, Ferdi; van Leeuwen, Ton G.

    2009-02-01

    Photoacoustic imaging is a relatively new medical imaging modality. In principle it can be used to image the optical absorption distribution of an object by measurements of optically induced acoustic signals. Recently we have developed a modified photoacoustic measurement system which can be used to simultaneously image the ultrasound propagation parameters as well. By proper placement of a passive element we obtain isolated measurements of the object's ultrasound propagation parameters, independent of the optical absorption inside the object. This passive element acts as a photoacoustic source and measurements are obtained by allowing the generated ultrasound signal to propagate through the object. Images of the ultrasound propagation parameters, being the attenuation and speed of sound, can then be reconstructed by inversion of a measurement model. This measurement model relates the projections non-linearly to the unknown images, due to ray refraction effects. After estimating the speed of sound and attenuation distribution, the optical absorption distribution is reconstructed. In this reconstruction problem we take into account the previously estimated speed of sound distribution. So far, the reconstruction algorithms have been tested using computer simulations. The method has been compared with existing algorithms and good results have been obtained.

  8. Measuring the Speed of Sound in a 1D Fermi Gas

    NASA Astrophysics Data System (ADS)

    Fry, Jacob; Revelle, Melissa; Hulet, Randall

    2016-05-01

    We report measurements of the speed of sound in a two-spin component, 1D gas of fermionic lithium. The 1D system is an array of one-dimensional tubes created by a 2D optical lattice. By increasing the lattice depth, the tunneling between tubes is sufficiently small to make each an independent 1D system. To measure the speed of sound, we create a density notch at the center of the atom cloud using a sheet of light tuned far from resonance. The dipole force felt by both spin states will be equivalent, so this notch can be thought of as a charge excitation. Once this beam is turned off, the notch propagates to the edge of the atomic cloud with a velocity that depends on the strength of interatomic interactions. We control interactions using a magnetically tuned Feshbach resonance, allowing us to measure the speed of sound over a wide range of interaction. This method may be used to extract the Luttinger parameter vs. interaction strength. Supported by an ARO MURI Grant, NSF, and The Welch Foundation.

  9. Evaluation Experiment of Ultrasound Computed Tomography for the Abdominal Sound Speed Imaging

    NASA Astrophysics Data System (ADS)

    Nogami, Keisuke; Yamada, Akira

    2007-07-01

    Abdominal sound speed tomographic imaging using through-transmission travel time data on the body surface was investigated. To this end, a hundred kHz range low-frequency wave was used to reduce the wave attenuation within an inner body medium. A method was investigated for the reconstruction of the image with the smallest possible number of path data around the abdominal surface. Specifically, the data from a strong scattering spinal cord should be avoided. To fulfill the requirement, the smoothed path algebraic reconstruction technique was introduced. The validity of this method was examined both on the numerically synthesized data and the experimentally measured data for the phantom specimen and actual human subject. It was shown that an abdominal tomographic sound speed image could be successfully obtained by preparing only 32 transducer locations at the circumference around the abdominal surface and their combination of less than 100 number of observation path data as well as by avoiding the data intersecting the spinal cord. In addition, fat regions were extracted having a sound speed lower than the threshold value to demonstrate the possibility of this method for metabolic syndrome diagnosis.

  10. Verification of the helioseismology travel-time measurement technique and the inversion procedure for sound speed using artificial data

    SciTech Connect

    Parchevsky, K. V.; Zhao, J.; Hartlep, T.; Kosovichev, A. G.

    2014-04-10

    We performed three-dimensional numerical simulations of the solar surface acoustic wave field for the quiet Sun and for three models with different localized sound-speed perturbations in the interior with deep, shallow, and two-layer structures. We used the simulated data generated by two solar acoustics codes that employ the same standard solar model as a background model, but utilize different integration techniques and different models of stochastic wave excitation. Acoustic travel times were measured using a time-distance helioseismology technique, and compared with predictions from ray theory frequently used for helioseismic travel-time inversions. It is found that the measured travel-time shifts agree well with the helioseismic theory for sound-speed perturbations, and for the measurement procedure with and without phase-speed filtering of the oscillation signals. This testing verifies the whole measuring-filtering-inversion procedure for static sound-speed anomalies with small amplitude inside the Sun outside regions of strong magnetic field. It is shown that the phase-speed filtering, frequently used to extract specific wave packets and improve the signal-to-noise ratio, does not introduce significant systematic errors. Results of the sound-speed inversion procedure show good agreement with the perturbation models in all cases. Due to its smoothing nature, the inversion procedure may overestimate sound-speed variations in regions with sharp gradients of the sound-speed profile.

  11. Phenomenology of D-brane inflation with general speed of sound

    SciTech Connect

    Peiris, Hiranya; Baumann, Daniel; Friedman, Brett; Cooray, Asantha

    2007-11-15

    A characteristic of D-brane inflation is that fluctuations in the inflaton field can propagate at a speed significantly less than the speed of light. This yields observable effects that are distinct from those of single-field slow-roll inflation, such as a modification of the inflationary consistency relation and a potentially large level of non-Gaussianities. We present a numerical algorithm that extends the inflationary flow formalism to models with general speed of sound. For an ensemble of D-brane-inflation models parametrized by the Hubble parameter and the speed of sound as polynomial functions of the inflaton field, we give qualitative predictions for the key inflationary observables. We discuss various consistency relations for D-brane inflation, and compare the qualitative shapes of the warp factors we derive from the numerical models with analytical warp factors considered in the literature. Finally, we derive and apply a generalized microphysical bound on the inflaton field variation during brane inflation. While a large number of models are consistent with current cosmological constraints, almost all of these models violate the compactification constraint on the field range in four-dimensional Planck units. If the field range bound is to hold, then models with a detectable level of non-Gaussianity predict a blue scalar spectral index, and a tensor component that is far below the detection limit of any future experiment.

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

    SciTech Connect

    IceCube Collaboration; Klein, Spencer

    2009-06-04

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

  13. GORRAM: Introducing accurate operational-speed radiative transfer Monte Carlo solvers

    NASA Astrophysics Data System (ADS)

    Buras-Schnell, Robert; Schnell, Franziska; Buras, Allan

    2016-06-01

    We present a new approach for solving the radiative transfer equation in horizontally homogeneous atmospheres. The motivation was to develop a fast yet accurate radiative transfer solver to be used in operational retrieval algorithms for next generation meteorological satellites. The core component is the program GORRAM (Generator Of Really Rapid Accurate Monte-Carlo) which generates solvers individually optimized for the intended task. These solvers consist of a Monte Carlo model capable of path recycling and a representative set of photon paths. Latter is generated using the simulated annealing technique. GORRAM automatically takes advantage of limitations on the variability of the atmosphere. Due to this optimization the number of photon paths necessary for accurate results can be reduced by several orders of magnitude. For the shown example of a forward model intended for an aerosol satellite retrieval, comparison with an exact yet slow solver shows that a precision of better than 1% can be achieved with only 36 photons. The computational time is at least an order of magnitude faster than any other type of radiative transfer solver. Merely the lookup table approach often used in satellite retrieval is faster, but on the other hand suffers from limited accuracy. This makes GORRAM-generated solvers an eligible candidate as forward model in operational-speed retrieval algorithms and data assimilation applications. GORRAM also has the potential to create fast solvers of other integrable equations.

  14. Optical Measurement of the Speed of Sound in Air Over the Temperature Range 300-650 K

    NASA Technical Reports Server (NTRS)

    Hart, Roger C.; Balla, R. Jeffrey; Herring, G. C.

    2000-01-01

    Using laser-induced thermal acoustics (LITA), the speed of sound in room air (1 atm) is measured over the temperature range 300-650 K. Since the LITA apparatus maintains a fixed sound wavelength as temperature is varied, this temperature range simultaneously corresponds to a sound frequency range of 10-15 MHz. The data are compared to a published model and typically agree within 0.1%-0.4% at each of 21 temperatures.

  15. Intensive sound speed monitoring in ocean and its impact on the GPS/acoustic seafloor geodetic measurement

    NASA Astrophysics Data System (ADS)

    Kido, Motoyuki

    2016-04-01

    GPS/acoustic (GPS/A) technique, based on GPS positioning and acoustic ranging, is now getting a popular tool to measure seafloor crustal movement. Several groups in the world have been intensively conducted campaign surveys in the region of scientifically interest. As the technology of measurement has been matured and plenty of data are accumulated, researchers are now aware of the limit of its precision mainly due to unexpected undulation of sound speed in ocean, which significantly degrades acoustic ranging. If sound speed structure keeps its figure during survey period, e.g., more than a couple of hours, it can be estimated by a moving survey to get sufficient paths from various directions to illustrate the structure. However the sound speed structure often varies quickly with in a hour due to internal gravitational wave excited by interaction of tidal current and seafloor topography. In this case one cannot separate temporal and spatial variations. We revisited our numerous sound speed profile data derived from numbers of XBT measurements, which were concurrently carried out with GPS/A survey along the Nankai Trough and Japan Trench. Among the measurements, we found notably short-period variation in sound speed profile through intensive XBT survey repeatedly cast every 6 minutes for one hour, which also appeared in residuals in traveltime of acoustic ranging. The same feature is also found in more moderate rate for semidiurnal undulation, in which vertical oscillation of the middle of the profile can be clearly seen rather than variation of absolute sound speed. This also reflects traveltime residuals in the GPS/A measurement. These typical frequencies represent dominant wavelengths of spatial sound speed variation. In the latter, local horizontal variation can be negligible in the vicinity of a point survey area and the traditional analysis can be applicable that assumes time-varying stratified sound speed structure. In the former case, on the contrary, local

  16. Properties of low-aspect-ratio pointed wings at speeds below and above the speed of sound

    NASA Technical Reports Server (NTRS)

    Jones, R. T.

    1976-01-01

    Low aspect ratio wings having pointed planforms are treated on the assumption that the flow potentials in planes at right angles of the long axis of the airfoils are similar to the corresponding two dimensional potentials. For the limiting case of small angles of attack and low aspect ratios the theory brings out the following significant properties: (1) the lift of a slender pointed airfoil moving in the direction of its long axis depends on the increase in width of the sections in a downstream direction; (2) spanwise loading of such an airfoil is independent of planform and approaches the distribution giving a minimum induced drag; and (3) lift distribution of a pointed airfoil traveling point-foremost is relatively unaffected by the compressibility of the air below or above the speed of sound.

  17. Measurement and analysis of radiated sound from a low speed fan with a large tip gap.

    PubMed

    Bilka, M J; Anthoine, J; Schram, C

    2014-05-01

    The wake flow field and radiated sound from a low speed axial fan is studied experimentally. The fan geometry uses controlled diffusion blades and is designed with a low aspect ratio (0.9). The fan is installed with a large tip gap, approximately 10% of the blade span. The radiated sound field is analyzed using a known trailing edge noise formulation. First, the model is compared to an experiment of a single airfoil in a wind tunnel to assess the predictive capabilities. Second, measurements of the fan are made at two different blade loading conditions. Hot wire measurements are made in the near wake of the fan to assess the extent of the tip leakage flow for each condition. The radiated sound fields are compared with the trailing edge noise theory. Use is made of the wake measurements as an input to a surface pressure model. When the fan is operated with the optimal blade loading, the influence of the tip leakage flow is found to be of secondary acoustic impact. When the fan is operated at a high loading condition for the blades, a more significant leakage flow develops and is found to be responsible for the dominant radiated sound.

  18. A time-accurate algorithm for chemical non-equilibrium viscous flows at all speeds

    NASA Technical Reports Server (NTRS)

    Shuen, J.-S.; Chen, K.-H.; Choi, Y.

    1992-01-01

    A time-accurate, coupled solution procedure is described for the chemical nonequilibrium Navier-Stokes equations over a wide range of Mach numbers. This method employs the strong conservation form of the governing equations, but uses primitive variables as unknowns. Real gas properties and equilibrium chemistry are considered. Numerical tests include steady convergent-divergent nozzle flows with air dissociation/recombination chemistry, dump combustor flows with n-pentane-air chemistry, nonreacting flow in a model double annular combustor, and nonreacting unsteady driven cavity flows. Numerical results for both the steady and unsteady flows demonstrate the efficiency and robustness of the present algorithm for Mach numbers ranging from the incompressible limit to supersonic speeds.

  19. Effect of rotatory instrument speed on its capacity to remove demineralized and sound dentin

    PubMed Central

    Cortes, Mariana; Pecorari, Vanessa Galego Arias; Basting, Roberta Tarkany; França, Fabiana Mantovani Gomes; Turssi, Cecília Pedroso; do Amaral, Flávia Lucisano Botelho

    2013-01-01

    Objectives: The aim of this study was to evaluate the capacity of two rotatory instruments (controlled speed electric motor [CSEM] – 300 rpm; conventional slow handpiece [CSHP] – 18,000 rpm) to remove sound and demineralized dentin, by examining prepared cavity walls using the scanning electron microscopy (SEM) and assessing loss of mass. Materials and Methods: A total of 40 blocks of human occlusal dentin, measuring 5 mm × 5 mm × 4 mm (L × W × H), were divided into two groups according to the substrate type in which the cavity preparation was performed: D - demineralized dentin; and S - sound dentin (control group). The groups were subdivided according to the rotatory instrument used for cavity preparation (n = 10): CSEM (300 rpm); and CSHP (18,000 rpm). In half of the dentin blocks, caries lesion induction was performed for 6 weeks. The preparation of the cavities was performed on a standardizing machine, using a cylindrical tungsten carbide burr. Before and after the preparation, specimens were dehydrated in an incubator at 60°C for 30 min. The initial and final mass (in mg) of each dentin block was measured 3 times using the digital precision balance to obtain the mean weight Following cavity preparation, all specimens were hemisected and SEM was used to blindly assess each half so that the lateral walls of the prepared cavity were measured in μm, accepting the average of two measurements as the total depth of the preparation. Non-parametric Mann-Whitney analysis was performed with a 5% of significance level. Results: Regarding the weight difference (mg), no significance was detected between the groups. Regarding depth (μm), a significant difference was found between the groups, so that the CSRM showed lower cavity depth when compared with CSHP, both in sound and demineralized dentin. Conclusions: Controlled speed rotatory instruments were found to be more conservative in removing both sound and demineralized dentin, in terms of preparation and depth

  20. SOUND-SPEED AND ATTENUATION IMAGING OF BREAST TISSUE USING WAVEFORM TOMOGRAPHY OF TRANSMISSION ULTRASOUND DATA

    SciTech Connect

    HUANG, LIANJIE; PRATT, R. GERHARD; DURIC, NEB; LITTRUP, PETER

    2007-01-25

    Waveform tomography results are presented from 800 kHz ultrasound transmission scans of a breast phantom, and from an in vivo ultrasound breast scan: significant improvements are demonstrated in resolution over time-of-flight reconstructions. Quantitative reconstructions of both sound-speed and inelastic attenuation are recovered. The data were acquired in the Computed Ultrasound Risk Evaluation (CURE) system, comprising a 20 cm diameter solid-state ultrasound ring array with 256 active, non-beamforming transducers. Waveform tomography is capable of resolving variations in acoustic properties at sub-wavelength scales. This was verified through comparison of the breast phantom reconstructions with x-ray CT results: the final images resolve variations in sound speed with a spatial resolution close to 2 mm. Waveform tomography overcomes the resolution limit of time-of-flight methods caused by finite frequency (diffraction) effects. The method is a combination of time-of-flight tomography, and 2-D acoustic waveform inversion of the transmission arrivals in ultrasonic data. For selected frequency components of the waveforms, a finite-difference simulation of the visco-acoustic wave equation is used to compute synthetic data in the current model, and the data residuals are formed by subtraction. The residuals are used in an iterative, gradient-based scheme to update the sound-speed and attenuation model to produce a reduced misfit to the data. Computational efficiency is achieved through the use of time-reversal of the data residuals to construct the model updates. Lower frequencies are used first, to establish the long wavelength components of the image, and higher frequencies are introduced later to provide increased resolution.

  1. Sound-speed and attenuation imaging of breast tissue using waveform tomography of transmission ultrasound data

    NASA Astrophysics Data System (ADS)

    Pratt, R. Gerhard; Huang, Lianjie; Duric, Neb; Littrup, Peter

    2007-03-01

    Waveform tomography results are presented from 800 kHz ultrasound transmission scans of a breast phantom, and from an in vivo ultrasound breast scan: significant improvements are demonstrated in resolution over time-of-flight reconstructions. Quantitative reconstructions of both sound-speed and inelastic attenuation are recovered. The data were acquired in the Computed Ultrasound Risk Evaluation (CURE) system, comprising a 20 cm diameter solid-state ultrasound ring array with 256 active, non-beamforming transducers. Waveform tomography is capable of resolving variations in acoustic properties at sub-wavelength scales. This was verified through comparison of the breast phantom reconstructions with x-ray CT results: the final images resolve variations in sound speed with a spatial resolution close to 2 mm. Waveform tomography overcomes the resolution limit of time-of-flight methods caused by finite frequency (diffraction) effects. The method is a combination of time-of-flight tomography, and 2-D acoustic waveform inversion of the transmission arrivals in ultrasonic data. For selected frequency components of the waveforms, a finite-difference simulation of the visco-acoustic wave equation is used to compute synthetic data in the current model, and the data residuals are formed by subtraction. The residuals are used in an iterative, gradient-based scheme to update the sound-speed and attenuation model to produce a reduced misfit to the data. Computational efficiency is achieved through the use of time-reversal of the data residuals to construct the model updates. Lower frequencies are used first, to establish the long wavelength components of the image, and higher frequencies are introduced later to provide increased resolution.

  2. Anomalous temperature dependence of speed of sound of bulk poly(N-isopropylacrylamide) hydrogels near the phase transition.

    PubMed

    Walker, Ezekiel; Reyes, Delfino; Krokhin, Arkadii; Neogi, Arup

    2014-07-01

    Bulk Poly(N-isopropylacrylamide) (PNIPAm) hydrogels are thermally responsive polymers that undergo a sharp volumetric phase transition around its lower critical solution temperature of 33 °C. The physical characteristics of bulk, micro-, and nano-form PNIPAm hydrogel have been well-studied, and have applications ranging from biomedical devices to mechanical actuators. An important physical characteristics which reveals lack of available information is speed of sound. Prior studies have utilized Brillouin scattering, multi-echo reflection ultrasound spectroscopy, the sing-around method, and others in measuring the speed of sound. We use a planar resonant cavity with bulk PNIPAm hydrogel in aqueous solution to determine the temperature dependent speed of sound around the lower critical solution temperature. The results show sharp nonmonotonic behavior of the sound velocity in vicinity of the phase transition.

  3. Oral and Hand Movement Speeds Are Associated with Expressive Language Ability in Children with Speech Sound Disorder

    ERIC Educational Resources Information Center

    Peter, Beate

    2012-01-01

    This study tested the hypothesis that children with speech sound disorder have generalized slowed motor speeds. It evaluated associations among oral and hand motor speeds and measures of speech (articulation and phonology) and language (receptive vocabulary, sentence comprehension, sentence imitation), in 11 children with moderate to severe SSD…

  4. Sound Sources Identified in High-Speed Jets by Correlating Flow Density Fluctuations With Far-Field Noise

    NASA Technical Reports Server (NTRS)

    Panda, Jayanta; Seasholtz, Richard G.

    2003-01-01

    Noise sources in high-speed jets were identified by directly correlating flow density fluctuation (cause) to far-field sound pressure fluctuation (effect). The experimental study was performed in a nozzle facility at the NASA Glenn Research Center in support of NASA s initiative to reduce the noise emitted by commercial airplanes. Previous efforts to use this correlation method have failed because the tools for measuring jet turbulence were intrusive. In the present experiment, a molecular Rayleigh-scattering technique was used that depended on laser light scattering by gas molecules in air. The technique allowed accurate measurement of air density fluctuations from different points in the plume. The study was conducted in shock-free, unheated jets of Mach numbers 0.95, 1.4, and 1.8. The turbulent motion, as evident from density fluctuation spectra was remarkably similar in all three jets, whereas the noise sources were significantly different. The correlation study was conducted by keeping a microphone at a fixed location (at the peak noise emission angle of 30 to the jet axis and 50 nozzle diameters away) while moving the laser probe volume from point to point in the flow. The following figure shows maps of the nondimensional coherence value measured at different Strouhal frequencies ([frequency diameter]/jet speed) in the supersonic Mach 1.8 and subsonic Mach 0.95 jets. The higher the coherence, the stronger the source was.

  5. Vortex/Body Interaction and Sound Generation in Low-Speed Flow

    NASA Technical Reports Server (NTRS)

    Kao, Hsiao C.

    1998-01-01

    The problem of sound generation by vortices interacting with an arbitrary body in a low-speed flow has been investigated by the method of matched asymptotic expansions. For the purpose of this report, it is convenient to divide the problem into three parts. In the first part the mechanism of the vortex/body interaction, which is essentially the inner solution in the inner region, is examined. The trajectories for a system of vortices rotating about their centroid are found to undergo enormous changes after interaction; from this, some interesting properties emerged. In the second part, the problem is formulated, the outer solution is found, matching is implemented, and solutions for acoustic pressure are obtained. In the third part, Fourier integrals are evaluated and predicated results presented. An examination of these results reveals the following: (a) the background noise can be either augmented or attenuated by a body after interaction, (b) sound generated by vortex/body interaction obeys a scaling factor, (C) sound intensity can be reduced substantially by positioning the vortex system in the "favorable" side of the body instead of the "unfavorable" side, and (d) acoustic radiation from vortex/bluff-body interaction is less than that from vortex/airfoil interaction under most circumstances.

  6. Experimental findings on the underwater measurements uncertainty of speed of sound and the alignment system

    NASA Astrophysics Data System (ADS)

    Santos, T. Q.; Alvarenga, A. V.; Oliveira, D. P.; Mayworm, R. C.; Souza, R. M.; Costa-Félix, R. P. B.

    2016-07-01

    Speed of sound is an important quantity to characterize reference materials for ultrasonic applications, for instance. The alignment between the transducer and the test body is an key activity in order to perform reliable and consistent measurement. The aim of this work is to evaluate the influence of the alignment system to the expanded uncertainty of such measurement. A stainless steel cylinder was previously calibrated on an out of water system typically used for calibration of non-destructive blocks. Afterwards, the cylinder was calibrated underwater with two distinct alignment system: fixed and mobile. The values were statistically compared to the out-of-water measurement, considered the golden standard for such application. For both alignment systems, the normalized error was less than 0.8, leading to conclude that the both measurement system (under and out-of-water) do not diverge significantly. The gold standard uncertainty was 2.7 m-s-1, whilst the fixed underwater system resulted in 13 m-s-1, and the mobile alignment system achieved 6.6 m-s-1. After the validation of the underwater system for speed of sound measurement, it will be applied to certify Encapsulated Tissue Mimicking Material as a reference material for biotechnology application.

  7. Ranging in an underwater medium with multiple isogradient sound speed profile layers.

    PubMed

    Ramezani, Hamid; Leus, Geert

    2012-01-01

    In this paper, we analyze the problem of acoustic ranging between sensor nodes in an underwater environment. The underwater medium is assumed to be composed of multiple isogradient sound speed profile (SSP) layers where in each layer the sound speed is linearly related to the depth. Furthermore, each sensor node is able to measure its depth and can exchange this information with other nodes. Under these assumptions, we first show how the problem of underwater localization can be converted to the traditional range-based terrestrial localization problem when the depth information of the nodes is known a priori. Second, we relate the pair-wise time of flight (ToF) measurements between the nodes to their positions. Next, based on this relation, we propose a novel ranging algorithm for an underwater medium. The proposed ranging algorithm considers reflections from the seabed and sea surface. We will show that even without any reflections, the transmitted signal may travel through more than one path between two given nodes. The proposed algorithm analyzes them and selects the fastest one (first arrival path) based on the measured ToF and the nodes' depth measurements. Finally, in order to evaluate the performance of the proposed algorithm we run several simulations and compare the results with other existing algorithms.

  8. Global Effects of Local Sound-Speed Perturbations in the Sun: A Theoretical Study

    NASA Astrophysics Data System (ADS)

    Hanasoge, S. M.; Larson, T. P.

    2008-09-01

    We study the effect of localized sound-speed perturbations on global mode frequencies by applying techniques of global helioseismology to numerical simulations of the solar acoustic wave field. Extending the method of realization-noise subtraction ( e.g., Hanasoge, Duvall, and Couvidat, Astrophys. J. 664, 1234, 2007) to global modes and exploiting the luxury of full spherical coverage, we are able to achieve very highly resolved frequency differences that are then used to study sensitivities and the signatures of the thermal asphericities. We find that i) global modes are almost twice as sensitive to sound-speed perturbations at the bottom of the convection zone in comparison to anomalies well inside the radiative interior ( r≲0.55 R ⊙), ii) the m degeneracy is lifted ever so slightly, as seen in the a coefficients, and iii) modes that propagate in the vicinity of the perturbations show small amplitude shifts. Through comparisons with error estimates obtained from Michelson Doppler Imager (MDI; Scherrer et al., Solar Phys. 162, 129, 1995) observations, we find that the frequency differences are detectable with a sufficiently long time series (70 642 days).

  9. Sound speed and oscillation frequencies for solar models evolved with Los Alamos ATOMIC opacities

    NASA Astrophysics Data System (ADS)

    Guzik, Joyce A.; Fontes, C. J.; Walczak, P.; Wood, S. R.; Mussack, K.; Farag, E.

    Los Alamos National Laboratory has calculated a new generation of radiative opacities (OPLIB data using the ATOMIC code) for elements with atomic number Z = 1-30 with improved physics input, updated atomic data, and finer temperature grid to replace the Los Alamos LEDCOP opacities released in the year 2000. We calculate the evolution of standard solar models including these new opacities, and compare with models evolved using the Lawrence Livermore National Laboratory OPAL opacities (Iglesias & Rogers 1996). We use the solar abundance mixture of Asplund et al. 2009. The Los Alamos ATOMIC opacities (Colgan et al. 2013a, 2013b, 2015) have steeper opacity derivatives than those of OPAL for temperatures and densities of the solar interior radiative zone. We compare the calculated nonadiabatic solar oscillation frequencies and solar interior sound speed to observed frequencies and helioseismic inferences. The calculated sound-speed profiles are similar for models evolved using either the updated Iben evolution code (see Guzik & Mussack 2010), or the MESA evolution code (Paxton et al. 2015). The LANL ATOMIC opacities partially mitigate the `solar abundance problem'.

  10. Efficient Approximation of Head-Related Transfer Functions in Subbands for Accurate Sound Localization

    PubMed Central

    Marelli, Damián; Baumgartner, Robert; Majdak, Piotr

    2015-01-01

    Head-related transfer functions (HRTFs) describe the acoustic filtering of incoming sounds by the human morphology and are essential for listeners to localize sound sources in virtual auditory displays. Since rendering complex virtual scenes is computationally demanding, we propose four algorithms for efficiently representing HRTFs in subbands, i.e., as an analysis filterbank (FB) followed by a transfer matrix and a synthesis FB. All four algorithms use sparse approximation procedures to minimize the computational complexity while maintaining perceptually relevant HRTF properties. The first two algorithms separately optimize the complexity of the transfer matrix associated to each HRTF for fixed FBs. The other two algorithms jointly optimize the FBs and transfer matrices for complete HRTF sets by two variants. The first variant aims at minimizing the complexity of the transfer matrices, while the second one does it for the FBs. Numerical experiments investigate the latency-complexity trade-off and show that the proposed methods offer significant computational savings when compared with other available approaches. Psychoacoustic localization experiments were modeled and conducted to find a reasonable approximation tolerance so that no significant localization performance degradation was introduced by the subband representation. PMID:26681930

  11. Properties of low-aspect-ratio pointed wings at speeds below and above the speed of sound

    NASA Technical Reports Server (NTRS)

    Jones, Robert T

    1946-01-01

    Low-aspect-ratio wings having pointed plan forms are treated on the assumption that the flow potentials in planes at right angles to the long axis of the airfoils are similar to the corresponding two-dimensional potentials. For the limiting case of small angles of attack and low aspect ratios the theory brings out the following significant properties: (1) The lift of a slender, pointed airfoil moving in the direction of its long axis depends on the increase in width of the sections in a downstream direction. Sections behind the section of maximum width develop no lift. (2) The spanwise loading of such an airfoil is independent of the plan form and approaches the distribution giving a minimum induced drag. (3) The lift distribution of a pointed airfoil travelling point-foremost is relatively unaffected by the compressibility of the air below or above the speed of sound. A best of a triangular airfoil at a Mach number of 1.75 verified the theoretical values of lift and center of pressure.

  12. Carotid atherosclerotic plaque characterisation by measurement of ultrasound sound speed in vitro at high frequency, 20 MHz.

    PubMed

    Brewin, M P; Srodon, P D; Greenwald, S E; Birch, M J

    2014-02-01

    This study aimed to utilise a tissue mimicking material (TMM) in order to embed in vitro carotid plaque tissue so that its acoustic properties could be assessed. Here, an International Electrotechnical Commission (IEC) agar-based TMM was adapted to a clear gel by removal of the particulates. This clear TMM was measured with sound speed at 1540 ms(-1) and an attenuation coefficient of 0.15 dB cm(-1)MHz(-1). Composite sound speed was then measured through the embedded material using a scanning acoustic microscope (SAM). Both broadband reflection and transmission techniques were performed on each plaque specimen in order to ensure the consistency of the measurement of sound speed, both at 21 °C and 37 °C. The plaque was measured at two temperatures to investigate any effect on the lipid content of the plaque. The contour maps from its associated attenuation plots were used to match the speed data to the photographic mask of the plaque outline. This physical matching was then used to derive the sound speed from the percentage composition seen in the histological data by solution of simultaneous equations. Individual speed values for five plaque components were derived; TMM, elastin, fibrous/collagen, calcification and lipid. The results for derived sound speed in the TMM were consistently close to the expected value of soft tissue, 1540 ms(-1). The fibrous tissue showed a mean value of 1584 ms(-1) at 37 °C. The derived sound speeds for elastic and lipid exhibited large inter-quartile ranges. The calcification had higher sound speed than the other plaque components at 1760-2000 ms(-1). The limitations here lay in the difficulties in the matching process caused by the inhomogeneity of the plaque material and shrinkage during the histological process. Future work may concentrate on more homogeneous material in order to derive sound speed data for separate components. Nevertheless, this study increases the known data ranges of the individual components within a plaque

  13. High-speed helicopter rotor noise - Shock waves as a potent source of sound

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Lee, Yung-Jang; Tadghighi, H.; Holz, R.

    1991-01-01

    In this paper we discuss the problem of high speed rotor noise prediction. In particular, we propose that from the point of view of the acoustic analogy, shocks around rotating blades are sources of sound. We show that, although for a wing at uniform steady rectilinear motion with shocks the volume quadrupole and shock sources cancel in the far field to the order of 1/r, this cannot happen for rotating blades. In this case, some cancellation between volume quadrupoles and shock sources occurs, yet the remaining shock noise contribution is still potent. A formula for shock noise prediction is presented based on mapping the deformable shock surface to a time independent region. The resulting equation is similar to Formulation 1A of Langley. Shock noise prediction for a hovering model rotor for which experimental noise data exist is presented. The comparison of measured and predicted acoustic data shows good agreement.

  14. Speed of Sound Versus Temperature Using PVC Pipes Open at Both Ends

    NASA Astrophysics Data System (ADS)

    Bacon, Michael E.

    2012-09-01

    In this paper we investigate the speed of sound in air as a function of temperature using a simple and inexpensive apparatus. For this experiment it is essential that the appropriate end corrections be taken into account. In a recent paper the end corrections for 2-in i.d. (5.04-cm) PVC pipes open at both ends were investigated. The air column resonance was excited using a paddle as in Blue Man Group® pipes.2 The "open end" end correction is given by 0.6133r in accordance with recent experiments3 and detailed theoretical calculations.4 This correction amounted to 1.56 cm for the 2-in PVC pipe used. However, the paddle end correction was found to be influenced by the transient position of the paddle during the excitation process. The paddle end correction was found to be 1.94 cm.

  15. Non-Gaussianity in multi-sound-speed disformally coupled inflation

    NASA Astrophysics Data System (ADS)

    van de Bruck, Carsten; Koivisto, Tomi; Longden, Chris

    2017-02-01

    Most, if not all, scalar-tensor theories are equivalent to General Relativity with a disformally coupled matter sector. In extra-dimensional theories such a coupling can be understood as a result of induction of the metric on a brane that matter is confined to. This article presents a first look at the non-Gaussianities in disformally coupled inflation, a simple two-field model that features a novel kinetic interaction. Cases with both canonical and Dirac-Born-Infeld (DBI) kinetic terms are taken into account, the latter motivated by the possible extra-dimensional origin of the disformality. The computations are carried out for the equilateral configuration in the slow-roll regime, wherein it is found that the non-Gaussianity is typically rather small and negative. This is despite the fact that the new kinetic interaction causes the perturbation modes to propagate with different sounds speeds, which may both significantly deviate from unity during inflation.

  16. Hadronic equation of state and speed of sound in thermal and dense medium

    NASA Astrophysics Data System (ADS)

    Nasser Tawfik, Abdel; Magdy, Hend

    2014-10-01

    The equation of state p(ɛ) and speed of sound squared cs2 are studied in grand canonical ensemble of all hadron resonances having masses ≤2 GeV. This large ensemble is divided into strange and non-strange hadron resonances and furthermore to pionic, bosonic and fermionic sectors. It is found that the pions represent the main contributors to cs2 and other thermodynamic quantities including the equation of state p(ɛ) at low temperatures. At high temperatures, the main contributions are added in by the massive hadron resonances. The speed of sound squared can be calculated from the derivative of pressure with respect to the energy density, ∂p/∂ɛ, or from the entropy-specific heat ratio, s/cv. It is concluded that the physics of these two expressions is not necessarily identical. They are distinguishable below and above the critical temperature Tc. This behavior is observed at vanishing and finite chemical potential. At high temperatures, both expressions get very close to each other and both of them approach the asymptotic value, 1/3. In the hadron resonance gas (HRG) results, which are only valid below Tc, the difference decreases with increasing the temperature and almost vanishes near Tc. It is concluded that the HRG model can very well reproduce the results of the lattice quantum chromodynamics (QCD) of ∂p/∂ɛ and s/cv, especially at finite chemical potential. In light of this, energy fluctuations and other collective phenomena associated with the specific heat might be present in the HRG model. At fixed temperatures, it is found that cs2 is not sensitive to the chemical potential.

  17. Using speed of sound measurements to constrain the Huygens probe descent profile

    NASA Astrophysics Data System (ADS)

    Svedhem, Håkan; Lebreton, Jean-Pierre; Zarnecki, John; Hathi, Brijen

    2004-02-01

    The Acoustic Properties Investigation (API) is a set of sensors for acoustic measurements in gases or liquids, making a part of the Surface Science Package (SSP) on the Huygens probe. It consists of two units, API-V (Velocity of sound) and API-S (Sounding). The API-V has two ultrasonic transducers sending and receiving acoustic pulses over an unobstructed path of 15 cm. An accurate timing circuit is measuring the time it takes to propagate over the distance. Measurements are made in both directions to eliminate the effect of a constant drift of the medium. The transducers have been optimised to operate at low pressure (high altitude) and will operate from about 60 km down to the surface. They will also perform well in case of landing in a liquid. The API-S unit is an acoustic sounder, sending short pulses at 15 kHz every second and listening for echoes in between. It will detect droplets in the atmosphere and for the last 100 m it will characterise the acoustic scattering properties of the surface below. It will also give an accurate value for the descend velocity during the last 100 m. In case of landing in a (liquid) lake/ocean it will measure the depth of the late-ocean down to a maximum of about 1000 m. Accurate measurements of the velocity of sound will, together with knowledge on the temperature, enable the mean molecular weight to be calculated along the descent trajectory. The temperature will be measured by complementary sensors inside the SSP Top Hat, near the API-V, and to a high accuracy by the HASI instrument at the periphery of the Huygens probe. The API units and associated electronics has been designed and build at the Research and Scientific Support Department at ESTEC, where also the testing and initial calibration has been done. Detailed calibration has been performed with different gas mixtures and at different temperatures in the Titan simulation chamber at the University of Kent, Canterbury, UK. Further supporting studies are planned in the

  18. Phase aberration correction by multi-stencils fast marching method using sound speed image in ultrasound computed tomography

    NASA Astrophysics Data System (ADS)

    Qu, Xiaolei; Azuma, Takashi; Lin, Hongxiang; Imoto, Haruka; Tamano, Satoshi; Takagi, Shu; Umemura, Shin-Ichiro; Sakuma, Ichiro; Matsumoto, Yoichiro

    2016-04-01

    Reflection image from ultrasound computed tomography (USCT) system can be obtained by synthetic aperture technique, however its quality is decreased by phase aberration caused by inhomogeneous media. Therefore, phase aberration correction is important to improve image quality. In this study, multi-stencils fast marching method (MSFMM) is employed for phase correction. The MSFMM is an accurate and fast solution of Eikonal equation which considers the refraction. The proposed method includes two steps. First, the MSFMM is used to compute sound propagation time from each element to each image gird point using sound speed image of USCT. Second, synthetic aperture technique is employed to obtain reflection image using the computed propagation time. To evaluate the proposed method, both numerical simulation and phantom experiment were conducted. With regard to numerical simulation, both quantitative and qualitative comparisons between reflection images with and without phase aberration correction were given. In the quantitative comparison, the diameters of point spread function (PSF) in reflection images of a two layer structure were presented. In the qualitative comparison, reflection images of simple circle and complex breast modes with phase aberration correction show higher quality than that without the correction. In respect to phantom experiment, a piece of breast phantom with artificial glandular structure inside was scanned by a USCT prototype, and the artificial glandular structure is able to be visible more clearly in the reflection image with phase aberration correction than in that without the correction. In this study, a phase aberration correction method by the MSFMM are proposed for reflection image of the USCT.

  19. Sound speed and thermal property measurements of inert materials: laser spectroscopy and the diamond-anvil cell

    SciTech Connect

    Zaug, J.M.

    1997-07-01

    An indispensable companion to dynamical physics experimentation, static high-pressure diamond-anvil cell research continues to evolve, with laser diagnostic, as an accurate and versatile experimental deep planetary properties have bootstrapped each other in a process that has produced even higher pressures; consistently improved calibrations of temperature and pressure under static and dynamic conditions; and unprecedented data and understanding of materials, their elasticity, equations of state (EOS), and transport properties under extreme conditions. A collection of recent pressure and/or temperature dependent acoustic and thermal measurements and deduced mechanical properties and EOS data are summarized for a wide range of materials including H2, H2O, H2S, D2S, CO2, CH4, N2O, CH3OH,, SiO2, synthetic lubricants, PMMA, single crystal silicates, and ceramic superconductors. Room P&T sound speed measurements are presented for the first time on single crystals of beta-HMX. New high-pressure and temperature diamond cell designed and pressure calibrant materials are reviewed.

  20. Scale-dependent CMB power asymmetry from primordial speed of sound and a generalized δ N formalism

    SciTech Connect

    Wang, Dong-Gang; Cai, Yi-Fu; Zhao, Wen; Zhang, Yang E-mail: yifucai@ustc.edu.cn E-mail: yzh@ustc.edu.cn

    2016-02-01

    We explore a plausible mechanism that the hemispherical power asymmetry in the CMB is produced by the spatial variation of the primordial sound speed parameter. We suggest that in a generalized approach of the δ N formalism the local e-folding number may depend on some other primordial parameters besides the initial values of inflaton. Here the δ N formalism is extended by considering the effects of a spatially varying sound speed parameter caused by a super-Hubble perturbation of a light field. Using this generalized δ N formalism, we systematically calculate the asymmetric primordial spectrum in the model of multi-speed inflation by taking into account the constraints of primordial non-Gaussianities. We further discuss specific model constraints, and the corresponding asymmetry amplitudes are found to be scale-dependent, which can accommodate current observations of the power asymmetry at different length scales.

  1. High-speed system for FBG-based measurements of vibration and sound

    NASA Astrophysics Data System (ADS)

    Karabacak, Devrez M.; Ibrahim, Selwan K.; Koumans, Yorick; Meulblok, Bastiaan; Knoppers, Rik

    2016-05-01

    Fiber Bragg Gratings (FBGs) allow for optical detection of localized physical effects without the need to couple the light out and back into a fiber, enabling robust and multiplexed sensor systems. The need of combining wide bandwidth and high resolution for dynamic sensing applications, like acoustics and vibrations, has presented significant challenges for FBG-based solutions. Here, we present a novel FBG-based measurement system enabled by using high-speed and highprecision tunable laser-based optical interrogation scheme. Multiple levels of integrated wavelength referencing coupled with low-noise high-speed electronics allow for spectral feature tracking at a resolution of <20 fm at kHz-frequencies. In combination with fiber accelerometers that employ unique force transmission mechanisms, amplifying strain on the Bragg grating and increasing the resonance frequency of the transducer, resolutions <10 μg (150 Hz bandwidth) to submg resolution in kHz-frequencies is achieved. Similarly, compact wavelength-multiplexed hydrophones with wide range linearity and dynamic range, sub-Pa resolution and flat-sensitivity down to static pressures are demonstrated. The sensors are demonstrated to be customizable to application-specific requirements, and designed to be scalable to large quantity reproducible manufacturing. In contrast to interferometry-based solutions, the tunable swept-laser detection scheme in combination with strain-based FBG sensors provides a cost-effective system that allows for easy scaling of sensor counts per fiber with multiple fibers being simultaneously recorded. Finally, the integrated high accuracy triggering and hybrid measurement capabilities present the potential to monitor sounds and vibrations in a wide range of applications from seismic surveys to machine and structural monitoring applications in harsh environments.

  2. Waveform inversion with source encoding for breast sound speed reconstruction in ultrasound computed tomography.

    PubMed

    Wang, Kun; Matthews, Thomas; Anis, Fatima; Li, Cuiping; Duric, Neb; Anastasio, Mark A

    2015-03-01

    Ultrasound computed tomography (USCT) holds great promise for improving the detection and management of breast cancer. Because they are based on the acoustic wave equation, waveform inversion-based reconstruction methods can produce images that possess improved spatial resolution properties over those produced by ray-based methods. However, waveform inversion methods are computationally demanding and have not been applied widely in USCT breast imaging. In this work, source encoding concepts are employed to develop an accelerated USCT reconstruction method that circumvents the large computational burden of conventional waveform inversion methods. This method, referred to as the waveform inversion with source encoding (WISE) method, encodes the measurement data using a random encoding vector and determines an estimate of the sound speed distribution by solving a stochastic optimization problem by use of a stochastic gradient descent algorithm. Both computer simulation and experimental phantom studies are conducted to demonstrate the use of the WISE method. The results suggest that the WISE method maintains the high spatial resolution of waveform inversion methods while significantly reducing the computational burden.

  3. Experimental evaluation of bone quality using speed of sound measurement in cadaver mandibles

    NASA Astrophysics Data System (ADS)

    Al Haffar, Iyad; Padilla, Frederic; Laugier, Pascal; Nefussi, Raphael; Kolta, Sami; Foucart, Jean-Michel

    2004-10-01

    This study is the first attempt to use speed of sound (SOS) as a new ultrasonic diagnostic tool for bone quality assessment before oral implant treatment. The objective is to demonstrate the in vitro feasibility of local SOS measurement at the mandible, and to investigate the relationships between mandibular SOS and local bone mineral density (BMD) and the ratio between the trabecular and cortical thickness (Tb.Th/Cort.Th). Fourteen excised human mandible were measured in transmission with a pair of flat 1.6-MHz central frequency transducers. Three regions of interest (ROIs) were selected in the specimens: incisor, premolar and molar regions. Ten measurements with repositioning were performed on each ROI to determine the short-term precision. Dual x-ray absorptiometry scans were performed on the samples for local BMD measurements. Computed tomography (CT) was used to determine mandibular cross-sectional morphological measurements. SOS measurements at different sites were significantly different, reflecting the heterogeneity between the different sites. A strong linear relationship was found between SOS and BMD (r2=0.68, p<0,0001) while a nonlinear relationship was found between SOS and Tb.Th/Cort.Th (r2=0.48, p<0,0001). This study demonstrates in vitro the feasibility of SOS measurement at the mandible. In vitro mandibular SOS reflects local BMD and Tb.Th/Cort.Th before implant.

  4. 101-SY waste sample speed of sound/rheology testing for sonic probe program

    SciTech Connect

    Cannon, N.S.

    1994-07-25

    One problem faced in the clean-up operation at Hanford is that a number of radioactive waste storage tanks are experiencing a periodic buildup and release of potentially explosive gases. The best known example is Tank 241-SY-101 (commonly referred to as 101-SY) in which hydrogen gas periodically built up within the waste to the point that increased buoyancy caused a roll-over event, in which the gas was suddenly released in potentially explosive concentrations (if an ignition source were present). The sonic probe concept is to generate acoustic vibrations in the 101-SY tank waste at nominally 100 Hz, with sufficient amplitude to cause the controlled release of hydrogen bubbles trapped in the waste. The sonic probe may provide a potentially cost-effective alternative to large mixer pumps now used for hydrogen mitigation purposes. Two important parameters needed to determine sonic probe effectiveness and design are the speed of sound and yield stress of the tank waste. Tests to determine these parameters in a 240 ml sample of 101-SY waste (obtained near the tank bottom) were performed, and the results are reported.

  5. Characteristics of distal radius speed of sound data in Chinese mainland men and women.

    PubMed

    Huang, Ligang; Pan, Jiafei; Jin, Hongting; Xiao, Luwei; Tao, Jing; Tong, Peijian

    2015-01-01

    Quantitative ultrasound (QUS) assessment of bone health status, as a reliable method, is rapidly gaining popularity. Speed of sound (SOS) is one parameter of skeletal status provided by QUS assessment. The objective of the present study was first to determine the normative distal radius SOS data on healthy Chinese mainland men and women and second to investigate the effects of sex, age, and body size on this parameter. A study cohort consisting of 19,980 healthy Chinese women and 8722 men aged 20-89 yr participated in this investigation. They answered a detailed questionnaire on their healthy condition, and their anthropometric measurements were taken. Their distal radius SOS values were evaluated using the Sunlight ultrasound systems. The distal radius SOS values exhibited a characteristic rise-then-fall pattern with increasing age in both sexes. The peak SOS value occurred at the age of 40-49 both in males and females. Age-related differences were both pronounced among males and females. Pearson correlation and regression analysis showed that age was a major determinant of SOS in both sexes. In females, SOS values had a much stronger correlation with age than male subjects. Body weight was also correlated with SOS but not as well as age. The SOS values of distal radius at present study may be used as normal reference data for Chinese mainland population and will be useful for comparing the results of individual studies and determining diagnostic criteria of osteoporosis by QUS.

  6. Waveform Inversion with Source Encoding for Breast Sound Speed Reconstruction in Ultrasound Computed Tomography

    PubMed Central

    Wang, Kun; Matthews, Thomas; Anis, Fatima; Li, Cuiping; Duric, Neb; Anastasio, Mark A.

    2016-01-01

    Ultrasound computed tomography (USCT) holds great promise for improving the detection and management of breast cancer. Because they are based on the acoustic wave equation, waveform inversion-based reconstruction methods can produce images that possess improved spatial resolution properties over those produced by ray-based methods. However, waveform inversion methods are computationally demanding and have not been applied widely in USCT breast imaging. In this work, source encoding concepts are employed to develop an accelerated USCT reconstruction method that circumvents the large computational burden of conventional waveform inversion methods. This method, referred to as the waveform inversion with source encoding (WISE) method, encodes the measurement data using a random encoding vector and determines an estimate of the sound speed distribution by solving a stochastic optimization problem by use of a stochastic gradient descent algorithm. Both computer-simulation and experimental phantom studies are conducted to demonstrate the use of the WISE method. The results suggest that the WISE method maintains the high spatial resolution of waveform inversion methods while significantly reducing the computational burden. PMID:25768816

  7. Searching for Minimum in Dependence of Squared Speed-of-Sound on Collision Energy

    DOE PAGES

    Liu, Fu-Hu; Gao, Li-Na; Lacey, Roy A.

    2016-01-01

    Experimore » mental results of the rapidity distributions of negatively charged pions produced in proton-proton ( p - p ) and beryllium-beryllium (Be-Be) collisions at different beam momentums, measured by the NA61/SHINE Collaboration at the super proton synchrotron (SPS), are described by a revised (three-source) Landau hydrodynamic model. The squared speed-of-sound parameter c s 2 is then extracted from the width of rapidity distribution. There is a local minimum (knee point) which indicates a softest point in the equation of state (EoS) appearing at about 40 A  GeV/ c (or 8.8 GeV) in c s 2 excitation function (the dependence of c s 2 on incident beam momentum (or center-of-mass energy)). This knee point should be related to the searching for the onset of quark deconfinement and the critical point of quark-gluon plasma (QGP) phase transition.« less

  8. Direct measurement of speed of sound in cartilage in situ using ultrasound and magnetic resonance images.

    PubMed

    Nitta, N; Aoki, T; Hyodo, K; Misawa, M; Homma, K

    2013-01-01

    This study verified the accuracy of the speed of sound (SOS) measured by the combination method, which calculates the ratio between the thickness values of cartilage measured by using the magnetic resonance imaging (MRI) and the ultrasonic pulse-echo imaging, and investigated in vivo application of this method. SOS specific to an ultrasound imaging device was used as a reference value to calculate the actual SOS from the ratio of cartilage thicknesses obtained from MR and ultrasound images. The accuracy of the thickness measurement was verified by comparing results obtained using MRI and a non-contact laser, and the accuracy of the calculated SOS was confirmed by comparing results of the pulse-echo and transmission methods in vitro. The difference between laser and MRI measurements was 0.05 ± 0.22 mm. SOS values in a human knee measured by the combination method in the medial and lateral femoral condyles were 1650 ± 79 and 1642 ± 78 m/s, respectively (p < 0.05). The results revealed the feasibility of in situ SOS measurement using the combination method.

  9. Optimising speed and energy expenditure in accurate visually directed upper limb movements.

    PubMed

    Elliott, Digby; Hansen, Steve; Grierson, Lawrence E M

    2009-04-01

    Traditional models of speed-accuracy relations and limb control are steady-state models that fail to consider the learning history and strategic approach of the performer. Work from this laboratory indicates that a performer adjusts his/her behaviour from trial-to-trial to optimise not only the speed and accuracy of performance, but also energy expenditure. Because some errors have greater temporal and energy costs than others, most performers execute movements that are prepared such that potential errors are of minimal expense. The trajectories and subsequent endpoint distributions of rapid aiming movements depend on advance knowledge about the availability of afferent information for online control, as well as the costs associated with undershooting or overshooting the target position with the initial impulse. With practice, a performer is able to reduce the trial-to-trial variability associated with goal-directed movement through more consistent movement planning processes and more rapid online control. Part of the optimisation process is related to the development of an internal model of performance against which early afferent feedback can be evaluated. This framework for examining speed, accuracy and energy expenditure in goal-directed reaching can be used to help understand the breakdown of efficient limb control due to fatigue, ageing and pathology.

  10. Full correction for spatially distributed speed-of-sound in echo ultrasound based on measuring aberration delays via transmit beam steering

    NASA Astrophysics Data System (ADS)

    Jaeger, Michael; Robinson, Elise; Günhan Akarçay, H.; Frenz, Martin

    2015-06-01

    Aberrations of the acoustic wave front, caused by spatial variations of the speed-of-sound, are a main limiting factor to the diagnostic power of medical ultrasound imaging. If not accounted for, aberrations result in low resolution and increased side lobe level, over all reducing contrast in deep tissue imaging. Various techniques have been proposed for quantifying aberrations by analysing the arrival time of coherent echoes from so-called guide stars or beacons. In situations where a guide star is missing, aperture-based techniques may give ambiguous results. Moreover, they are conceptually focused on aberrators that can be approximated as a phase screen in front of the probe. We propose a novel technique, where the effect of aberration is detected in the reconstructed image as opposed to the aperture data. The varying local echo phase when changing the transmit beam steering angle directly reflects the varying arrival time of the transmit wave front. This allows sensing the angle-dependent aberration delay in a spatially resolved way, and thus aberration correction for a spatially distributed volume aberrator. In phantoms containing a cylindrical aberrator, we achieved location-independent diffraction-limited resolution as well as accurate display of echo location based on reconstructing the speed-of-sound spatially resolved. First successful volunteer results confirm the clinical potential of the proposed technique.

  11. Postnatal Changes in Tibial Bone Speed of Sound of Preterm and Term Infants during Infancy.

    PubMed

    Chen, Hsiu-Lin; Lee, Wei-Te; Lee, Pei-Lun; Liu, Po-Len; Yang, Rei-Cheng

    2016-01-01

    This study aimed to evaluate changes in tibial bone speed of sound (SOS) over time, in preterm and term infants during infancy, in addition to identifying factors influencing the development of tibial SOS during infancy. Preterm (n = 155) and term (n = 65) infants were enrolled in this study. Tibial bone SOS was measured using quantitative ultrasonography (QUS) on the left tibia of newborn infants after birth (within 7 days), at 1 month old, and then every 2 months until subjects were approximately 12-15 months old. Follow-up checks included anthropometric measurements and tibial bone SOS. Mean tibial bone SOS at birth was significantly higher in term infants (mean ± SD, 2968.5 ± 99.7 m/s) than in preterm infants (2912.2 ± 122.6 m/s). Values of follow-up tibial bone SOS declined for the first 4 months, and then increased gradually until 12-15 months old. This increasing trend was greater in preterm infants after 2 months of corrected age than in term infants. There were no significant differences by 12-15 months of age between preterm and term infants. A longitudinal mixed-effect model controlling for internal correlations and other covariates in the two groups showed that age and the SOS value at birth were important factors affecting the tibial bone SOS in both preterm and term newborn infants during infancy. There are significant differences in the pattern of change in tibial bone SOS values between preterm and term infants during the first 12-15 months of life. Age and SOS value at birth were important factors affecting the pattern of tibial bone SOS change in both preterm and term newborn infants during infancy.

  12. Sound speed and oscillation frequencies for a solar model evolved with Los Alamos ATOMIC opacities

    NASA Astrophysics Data System (ADS)

    Guzik, Joyce Ann; Fontes, Christopher; Walczak, Przemyslaw; Wood, Suzannah R.; Mussack, Katie

    2015-08-01

    Los Alamos has calculated a new generation of radiative opacities for elements with atomic number Z=1-30 with improved physics input, updated atomic data, and finer temperature grid to replace the Los Alamos LEDCOP opacities released in the year 2000. We calculate the evolution of a standard solar model including these new opacities, and compare with a model evolved using the Lawrence Livermore National Laboratory OPAL opacities released about 1996. We use the solar abundance mixture of Asplund, Grevesse, Sauval, and Scott (2009), including 2015 updates. The Los Alamos ATOMIC opacities (Colgan et al. 2013a,b) are somewhat higher than those of OPAL for temperatures and densities near the base of the solar convection zone. We compare the calculated nonadiabatic solar oscillation frequencies and solar interior sound speed to observed frequencies and helioseismic inferences. We discuss the potential for increased opacities to partially mitigate the ‘solar abundance problem’.References:J. Colgan, D.P. Kilcrease, N.H. Magee, Jr., G.S.J. Armstrong, J. Abdallah, Jr., M.E. Sherrill, C.J. Fontes, H.L. Zhang and P. Hakel, Eighth International Conference on Atomic and Molecular Data and their Applications: ICAMDATA, Gaithersburg, MD 2012, AIP Conf. Proc. No. 1545, (AIP, New York, 2013a), pp. 17-26.J. Colgan, D.P. Kilcrease, N.H. Magee, Jr, G.S.J. Armstrong, J. Abdallah, Jr., M.E. Sherrill, C.J. Fontes, H.L. Zhang and P. Hakel, High Energy Density Physics 9, 369 (2013b).

  13. In situ acoustic and laboratory ultrasonic sound speed and attenuation measured in heterogeneous soft seabed sediments: Eel River shelf, California

    USGS Publications Warehouse

    Gorgas, T.J.; Wilkens, R.H.; Fu, S.S.; Neil, Frazer L.; Richardson, M.D.; Briggs, K.B.; Lee, H.

    2002-01-01

    We compared in situ and laboratory velocity and attenuation values measured in seafloor sediments from the shallow water delta of the Eel River, California. This region receives a substantial volume of fluvial sediment that is discharged annually onto the shelf. Additionally, a high input of fluvial sediments during storms generates flood deposits that are characterized by thin beds of variable grain-sizes between the 40- and 90-m isobaths. The main objectives of this study were (1) to investigate signatures of seafloor processes on geoacoustic and physical properties, and (2) to evaluate differences between geoacoustic parameters measured in situ at acoustic (7.5 kHz) and in the laboratory at ultrasonic (400 kHz) frequencies. The in situ acoustic measurements were conducted between 60 and 100 m of water depth. Wet-bulk density and porosity profiles were obtained to 1.15 m below seafloor (m bsf) using gravity cores of the mostly cohesive fine-grained sediments across- and along-shelf. Physical and geoacoustic properties from six selected sites obtained on the Eel margin revealed the following. (1) Sound speed and wet-bulk density strongly correlated in most cases. (2) Sediment compaction with depth generally led to increased sound speed and density, while porosity and in situ attenuation values decreased. (3) Sound speed was higher in coarser- than in finer-grained sediments, on a maximum average by 80 m s-1. (4) In coarse-grained sediments sound speed was higher in the laboratory (1560 m s-1) than in situ (1520 m s-1). In contrast, average ultrasonic and in situ sound speed in fine-grained sediments showed only little differences (both approximately 1480 m s-1). (5) Greater attenuation was commonly measured in the laboratory (0.4 and 0.8 dB m-1 kHz-1) than in situ (0.02 and 0.65 dB m-1 kHz-1), and remained almost constant below 0.4 m bsf. We attributed discrepancies between laboratory ultrasonic and in situ acoustic measurements to a frequency dependence of

  14. Measurement of the speed of sound by observation of the Mach cones in a complex plasma under microgravity conditions

    NASA Astrophysics Data System (ADS)

    Zhukhovitskii, D. I.; Fortov, V. E.; Molotkov, V. I.; Lipaev, A. M.; Naumkin, V. N.; Thomas, H. M.; Ivlev, A. V.; Schwabe, M.; Morfill, G. E.

    2015-02-01

    We report the first observation of the Mach cones excited by a larger microparticle (projectile) moving through a cloud of smaller microparticles (dust) in a complex plasma with neon as a buffer gas under microgravity conditions. A collective motion of the dust particles occurs as propagation of the contact discontinuity. The corresponding speed of sound was measured by a special method of the Mach cone visualization. The measurement results are incompatible with the theory of ion acoustic waves. The estimate for the pressure in a strongly coupled Coulomb system and a scaling law for the complex plasma make it possible to derive an evaluation for the speed of sound, which is in a reasonable agreement with the experiments in complex plasmas.

  15. Measurement of the speed of sound by observation of the Mach cones in a complex plasma under microgravity conditions

    SciTech Connect

    Zhukhovitskii, D. I. Fortov, V. E.; Molotkov, V. I.; Lipaev, A. M.; Naumkin, V. N.; Thomas, H. M.; Ivlev, A. V.; Morfill, G. E.; Schwabe, M.

    2015-02-15

    We report the first observation of the Mach cones excited by a larger microparticle (projectile) moving through a cloud of smaller microparticles (dust) in a complex plasma with neon as a buffer gas under microgravity conditions. A collective motion of the dust particles occurs as propagation of the contact discontinuity. The corresponding speed of sound was measured by a special method of the Mach cone visualization. The measurement results are incompatible with the theory of ion acoustic waves. The estimate for the pressure in a strongly coupled Coulomb system and a scaling law for the complex plasma make it possible to derive an evaluation for the speed of sound, which is in a reasonable agreement with the experiments in complex plasmas.

  16. 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.

  17. Low-frequency sound speed and attenuation in sandy seabottom from long-range broadband acoustic measurements.

    PubMed

    Wan, Lin; Zhou, Ji-Xun; Rogers, Peter H

    2010-08-01

    A joint China-U.S. underwater acoustics experiment was conducted in the Yellow Sea with a very flat bottom and a strong and sharp thermocline. Broadband explosive sources were deployed both above and below the thermocline along two radial lines up to 57.2 km and a quarter circle with a radius of 34 km. Two inversion schemes are used to obtain the seabottom sound speed. One is based on extracting normal mode depth functions from the cross-spectral density matrix. The other is based on the best match between the calculated and measured modal arrival times for different frequencies. The inverted seabottom sound speed is used as a constraint condition to extract the seabottom sound attenuation by three methods. The first method involves measuring the attenuation coefficients of normal modes. In the second method, the seabottom sound attenuation is estimated by minimizing the difference between the theoretical and measured modal amplitude ratios. The third method is based on finding the best match between the measured and modeled transmission losses (TLs). The resultant seabottom attenuation, averaged over three independent methods, can be expressed as alpha=(0.33+/-0.02)f(1.86+/-0.04)(dB/m kHz) over a frequency range of 80-1000 Hz.

  18. Techniques for determining propulsion system forces for accurate high speed vehicle drag measurements in flight

    NASA Technical Reports Server (NTRS)

    Arnaiz, H. H.

    1975-01-01

    As part of a NASA program to evaluate current methods of predicting the performance of large, supersonic airplanes, the drag of the XB-70 airplane was measured accurately in flight at Mach numbers from 0.75 to 2.5. This paper describes the techniques used to determine engine net thrust and the drag forces charged to the propulsion system that were required for the in-flight drag measurements. The accuracy of the measurements and the application of the measurement techniques to aircraft with different propulsion systems are discussed. Examples of results obtained for the XB-70 airplane are presented.

  19. Laser Measurement of the Speed of Sound in Gases: A Novel Approach to Determining Heat Capacity Ratios and Gas Composition

    ERIC Educational Resources Information Center

    Baum, J. Clayton; Compton, R. N.; Feigerle, Charles S.

    2008-01-01

    The speed of sound is measured in several gases using a pulsed laser to create a micro-spark on a carbon rod and a microphone connected to a digital oscilloscope to measure the time-of-flight of the resulting shockwave over a known distance. These data are used to calculate the heat capacity ratios (C[subscript p]/C[subscript V]) of the gases and…

  20. Probing dark energy perturbations: The dark energy equation of state and speed of sound as measured by WMAP

    NASA Astrophysics Data System (ADS)

    Bean, Rachel; Doré, Olivier

    2004-04-01

    We review the implications of having a nontrivial matter component in the Universe and the potential for detecting such a component through the matter power spectrum and integrated Sachs-Wolfe effect. We adopt a phenomenological approach and consider the mysterious dark energy to be a cosmic fluid. It is thus fully characterized, up to linear order, by its equation of state and its speed of sound. Whereas the equation of state has been widely studied in the literature, less interest has been devoted to the speed of sound. Its observational consequences come predominantly from very large scale modes of dark matter perturbations (k<0.01h Mpc-1). Since these modes have hardly been probed so far by large scale galaxy surveys, we investigate whether joint constraints can be placed on those two quantities using the recent cosmic microwave background (CMB) fluctuations measurements by the Wilkinson Microwave Anisotropy Probe as well as the recently measured CMB large scale structure cross correlation. We find only a tentative 1 sigma detection of the speed of sound, from CMB alone, c2s<0.04 at this low significance level. Furthermore, the current uncertainties in bias in the matter power spectrum preclude any constraints being placed using the cross correlation of CMB with the NRAO VLA Sky Survey radio survey.

  1. Density and sound speed of two gelatinous zooplankton: ctenophore (Mnemiopsis leidyi) and lion's mane jellyfish (Cyanea capillata).

    PubMed

    Warren, Joseph D; Smith, Joy N

    2007-07-01

    The density and sound speed of two coastal, gelatinous zooplankton, Mnemiopsis leidyi (a ctenophore) and Cyanea capillata (lion's mane jellyfish), were measured. These parameters are important inputs to acoustic scattering models. Two different methods were used to measure the density of individual animals: one used a balance and graduated cylinder to determine the mass and displacement volume of the animal, the other varied the density of the solution the animal was immersed in. When the same animal was measured using both methods, density values were within 1% of each other. A travel-time difference method was used to measure the sound speed within the animals. The densities of both zooplankton slightly decreased as the animals increased in length, mass, and volume. The ratio of animal density and sound speed to the surrounding seawater (g and h, respectively) are reported for both animals. For Mnemiopsis leidyi ranging in length from 1 to 5 cm, the mean value (+/-standard deviation) of g and h were 1.009 (+/-0.004) and 1.007 (+/-0.001). For Cyanea capillata ranging in bell diameter from 2 to 11 cm, the mean value (+/-standard deviation) of g and single value of h were 1.009 (+/-0.004) and 1.0004.

  2. Multi-frequency characterization of the speed of sound and attenuation coefficient for longitudinal transmission of freshly excised human skulls.

    PubMed

    Pichardo, Samuel; Sin, Vivian W; Hynynen, Kullervo

    2011-01-07

    For medical applications of ultrasound inside the brain, it is necessary to understand the relationship between the apparent density of skull bone and its corresponding speed of sound and attenuation coefficient. Although there have been previous studies exploring this phenomenon, there is still a need to extend the measurements to cover more of the clinically relevant frequency range. The results of measurements of the longitudinal speed of sound and attenuation coefficient are presented for specimens of human calvaria. The study was performed for the frequencies of 0.27, 0.836, 1.402, 1.965 and 2.525 MHz. Specimens were obtained from fresh cadavers through a protocol with the Division of Anatomy of the University of Toronto. The protocol was approved by the Research Ethics Board of Sunnybrook Health Sciences Centre. The specimens were mounted in polycarbonate supports that were marked for stereoscopic positioning. Computer tomography (CT) scans of the skulls mounted on their supports were performed, and a three-dimensional skull surface was reconstructed. This surface was used to guide a positioning system to ensure the normal sound incidence of an acoustic signal. This signal was produced by a focused device with a diameter of 5 cm and a focal length of 10 cm. Measurements of delay in time of flight were carried out using a needle hydrophone. Measurements of effective transmitted energy were carried out using a radiation force method with a 10 µg resolution scale. Preliminary functions of speed of sound and attenuation coefficient, both of which are related to apparent density, were established using a multi-layer propagation model that takes into account speed of sound, density and thickness of the layer. An optimization process was executed from a large set of random functions and the best functions were chosen for those ones that closest reproduced the experimental observations. The final functions were obtained after a second pass of the optimization

  3. Multi-frequency characterization of the speed of sound and attenuation coefficient for longitudinal transmission of freshly excised human skulls

    NASA Astrophysics Data System (ADS)

    Pichardo, Samuel; Sin, Vivian W.; Hynynen, Kullervo

    2011-01-01

    For medical applications of ultrasound inside the brain, it is necessary to understand the relationship between the apparent density of skull bone and its corresponding speed of sound and attenuation coefficient. Although there have been previous studies exploring this phenomenon, there is still a need to extend the measurements to cover more of the clinically relevant frequency range. The results of measurements of the longitudinal speed of sound and attenuation coefficient are presented for specimens of human calvaria. The study was performed for the frequencies of 0.27, 0.836, 1.402, 1.965 and 2.525 MHz. Specimens were obtained from fresh cadavers through a protocol with the Division of Anatomy of the University of Toronto. The protocol was approved by the Research Ethics Board of Sunnybrook Health Sciences Centre. The specimens were mounted in polycarbonate supports that were marked for stereoscopic positioning. Computer tomography (CT) scans of the skulls mounted on their supports were performed, and a three-dimensional skull surface was reconstructed. This surface was used to guide a positioning system to ensure the normal sound incidence of an acoustic signal. This signal was produced by a focused device with a diameter of 5 cm and a focal length of 10 cm. Measurements of delay in time of flight were carried out using a needle hydrophone. Measurements of effective transmitted energy were carried out using a radiation force method with a 10 µg resolution scale. Preliminary functions of speed of sound and attenuation coefficient, both of which are related to apparent density, were established using a multi-layer propagation model that takes into account speed of sound, density and thickness of the layer. An optimization process was executed from a large set of random functions and the best functions were chosen for those ones that closest reproduced the experimental observations. The final functions were obtained after a second pass of the optimization

  4. A Polymer Visualization System with Accurate Heating and Cooling Control and High-Speed Imaging

    PubMed Central

    Wong, Anson; Guo, Yanting; Park, Chul B.; Zhou, Nan Q.

    2015-01-01

    A visualization system to observe crystal and bubble formation in polymers under high temperature and pressure has been developed. Using this system, polymer can be subjected to a programmable thermal treatment to simulate the process in high pressure differential scanning calorimetry (HPDSC). With a high-temperature/high-pressure view-cell unit, this system enables in situ observation of crystal formation in semi-crystalline polymers to complement thermal analyses with HPDSC. The high-speed recording capability of the camera not only allows detailed recording of crystal formation, it also enables in situ capture of plastic foaming processes with a high temporal resolution. To demonstrate the system’s capability, crystal formation and foaming processes of polypropylene/carbon dioxide systems were examined. It was observed that crystals nucleated and grew into spherulites, and they grew at faster rates as temperature decreased. This observation agrees with the crystallinity measurement obtained with the HPDSC. Cell nucleation first occurred at crystals’ boundaries due to CO2 exclusion from crystal growth fronts. Subsequently, cells were nucleated around the existing ones due to tensile stresses generated in the constrained amorphous regions between networks of crystals. PMID:25915031

  5. Radiated Sound of a High-Speed Water-Jet-Propelled Transportation Vessel.

    PubMed

    Rudd, Alexis B; Richlen, Michael F; Stimpert, Alison K; Au, Whitlow W L

    2016-01-01

    The radiated noise from a high-speed water-jet-propelled catamaran was measured for catamaran speeds of 12, 24, and 37 kn. The radiated noise increased with catamaran speed, although the shape of the noise spectrum was similar for all speeds and measuring hydrophone depth. The spectra peaked at ~200 Hz and dropped off continuously at higher frequencies. The radiated noise was 10-20 dB lower than noise from propeller-driven ships at comparable speeds. The combination of low radiated noise and high speed could be a factor in the detection and avoidance of water-jet-propelled ships by baleen whales.

  6. 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.

  7. Comparison of International Reference Values for Bone Speed of Sound in Pediatric Populations: Meta-analysis.

    PubMed

    Rivas-Ruiz, R; Méndez-Sánchez, L; Castelán-Martínez, O D; Clark, P; Tamayo, J; Talavera, J O; Huitrón, G; Salmerón-Castro, J

    2016-01-01

    The aim of this study was to compare international reference values (RV) for tibial and radial speed of sound (SoS) assessed by quantitative ultrasound (QUS) in pediatric populations. These values were compared by age and country of origin in a systematic review with meta-analysis from studies published on QUS (Sunlight Omnisense). A search was carried out in electronic databases. Nine studies with 6963 patients were included in the meta-analysis. For the newborn populations, 3 studies (from Italy, Portugal, and Israel) were used. These studies included subjects with 27-42 wk gestational age. The mean difference (Portugal-Israel) was found to be 23.62 m/s [95% confidence interval [CI] 6.29, 40.95]. Additionally, no difference was found between Italy-Portugal (p = 0.69), or Italy-Israel (p = 0.28). In pediatric populations, we compared 8 studies from Canada, Mexico, Israel, Greece, Portugal, and Turkey. No significant differences found for SoS RV between Israel-Turkey, Israel-Greece, or Israel-Canada (p > 0.05). Significant differences were found in Mexico-Israel -105.29 m/s (95% CI -140.05, -70.54) (p < 0.001); Mexico-Portugal -115.14 m/s (95% CI -164.86, -65.42) (p < 0.001); Mexico-Greece: -239.14 m/s (95% CI -267.67, -210.62) (p < 0.001); Mexico-Turkey: -115.14 m/s (95% CI -164.86, -65.42) (p < 0.001); Mexico-Canada: -113.51 m/s (95% CI -140.25, -86.77) (p < 0.001).This study demonstrates that there are differences in SoS-RV obtained by tibial and radial QUS in pediatric populations between Mexico and other countries (Israel, Portugal, Greece, Turkey, and Canada).

  8. Study on sound-speed dispersion in a sandy sediment at frequency ranges of 0.5-3 kHz and 90-170 kHz

    NASA Astrophysics Data System (ADS)

    Yu, Sheng-qi; Liu, Bao-hua; Yu, Kai-ben; Kan, Guang-ming; Yang, Zhi-guo

    2017-03-01

    In order to study the properties of sound-speed dispersion in a sandy sediment, the sound speed was measured both at high frequency (90-170 kHz) and low frequency (0.5-3 kHz) in laboratory environments. At high frequency, a sampling measurement was conducted with boiled and uncooked sand samples collected from the bottom of a large water tank. The sound speed was directly obtained through transmission measurement using single source and single hydrophone. At low frequency, an in situ measurement was conducted in the water tank, where the sandy sediment had been homogeneously paved at the bottom for a long time. The sound speed was indirectly inverted according to the traveling time of signals received by three buried hydrophones in the sandy sediment and the geometry in experiment. The results show that the mean sound speed is approximate 1710-1713 m/s with a weak positive gradient in the sand sample after being boiled (as a method to eliminate bubbles as much as possible) at high frequency, which agrees well with the predictions of Biot theory, the effective density fluid model (EDFM) and Buckingham's theory. However, the sound speed in the uncooked sandy sediment obviously decreases (about 80%) both at high frequency and low frequency due to plenty of bubbles in existence. And the sound-speed dispersion performs a weak negative gradient at high frequency. Finally, a water-unsaturated Biot model is presented for trying to explain the decrease of sound speed in the sandy sediment with plenty of bubbles.

  9. On the significance of density-induced speed of sound variations on US-guided radiotherapy

    SciTech Connect

    Fontanarosa, Davide; Meer, Skadi van der; Verhaegen, Frank

    2012-10-15

    Purpose: To show the effect of speed of sound (SOS) aberration on ultrasound guided radiotherapy (US-gRT) as a function of implemented workflow. US systems assume that SOS is constant in human soft tissues (at a value of 1540 m/s), while its actual nonuniform distribution produces small but systematic errors of up to a few millimeters in the positions of scanned structures. When a coregistered computerized tomography (CT) scan is available, the US image can be corrected for SOS aberration. Typically, image guided radiotherapy workflows implementing US systems only provide a CT scan at the simulation (SIM) stage. If changes occur in geometry or density distribution between SIM and treatment (TX) stage, SOS aberration can change accordingly, with a final impact on the measured position of structures which is dependent on the workflow adopted. Methods: Four basic scenarios were considered of possible changes between SIM and TX: (1) No changes, (2) only patient position changes (rigid rotation-translation), (3) only US transducer position changes (constrained on patient's surface), and (4) patient tissues thickness changes. Different SOS aberrations may arise from the different scenarios, according to the specific US-gRT workflow used: intermodality (INTER) where TX US scans are compared to SIM CT scans; intramodality (INTRA) where TX US scans are compared to SIM US scans; and INTERc and INTRAc where all US images are corrected for SOS aberration (using density information provided by SIM CT). For an experimental proof of principle, the effect of tissues thickness change was simulated in the different workflows: a dual layered phantom was filled with layers of sunflower oil (SOS 1478 m/s), water (SOS 1482 m/s), and 20% saline solution (SOS 1700 m/s). The phantom was US scanned, the layer thicknesses were increased and the US scans were repeated. The errors resulting from the different workflows were compared. Results: Theoretical considerations show that workflows

  10. Bone speed of sound and physical activity levels of overweight and normal-weight girls and adolescents.

    PubMed

    Yao, Mathew; Ludwa, Izabella; Corbett, Lauren; Klentrou, Panagiota; Bonsu, Peter; Gammage, Kimberley; Falk, Bareket

    2011-02-01

    Bone properties, reflected by speed of sound (SOS), and physical activity levels were examined in overweight (OW) girls (n = 19) and adolescents (n = 22), in comparison with normal-weight (NW) girls (n = 21) and adolescents (n = 13). Moderate-to-vigorous physical activity (MVPA) was higher in NW than in OW in both age groups. Tibial SOS was lower in OW compared with NW in both age groups. MVPA correlated with tibial SOS, once age was partialed out. The results suggest that overweight girls and adolescents are characterized by low tibial SOS, which may be partially attributed to lower physical activity levels.

  11. 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

  12. A pilot study of measurement of the frequency of sounds emitted by high-speed dental air turbines.

    PubMed

    Altinöz, H C; Gökbudak, R; Bayraktar, A; Belli, S

    2001-09-01

    Since the development and use of the high-speed dental air turbine some 45 years ago, concern has been expressed in the literature about a possible cause and effect relationship between use of the drill and hearing loss in dentists. The hearing threshold in humans varies with the frequency of sound. It is well known that dentists experience gradual hearing loss during their working life. The aim of this study was to measure the frequency of sounds emitted by high-speed dental air turbines under different working conditions. Five high-speed dental air turbines were used (2 x Trend TC-80 BC W&H Dentalwerk, Austria, 2 x Black Pearl Eco Bien-air, Switzerland, 1 x Trend TC-80 BC W&H Dentalwerk, Austria. Each turbine was tested under 8 different working conditions: under free working conditions the turbines were tested without burs, with fissure burs, with flare burs, with round burs and with inverted cone burs; under operation they were tested with fissure burs by application to a 3 x 3 x 10 mm amalgam block surface, a 3 x 3 x 10 mm composite block surface, and the occlusal surface of an extracted molar tooth. Forty sound recordings were made in total using a computer with a microphone (Shure 16 LC) located 30 cm away from the samples, at 10-s intervals using a mixer. Frequency analysis was done by a Cool Edit Pro 1.2 computer program. Data were analyzed by multi-variate analysis with the S.P.S.S 9.05 software program. The average measurement was 6860 Hz. According to the statistical analysis there was no significant difference in the frequencies recorded under different working conditions. There was also no significant difference among the different high-speed dental air turbines at alpha = 0,05, P > alpha /2 levels. These results indicate that under any working conditions, high-speed dental air turbines emit frequencies which can cause hearing loss.

  13. Image reconstruction and system optimization for three-dimensional speed of sound tomography using laser-induced ultrasound

    NASA Astrophysics Data System (ADS)

    Anis, Fatima; Su, Richard; Nadvoretsky, Vyacheslav V.; Conjusteau, André; Ermilov, Sergey A.; Oraevsky, Alexander A.; Anastasio, Mark A.

    2013-03-01

    We developed the first prototype of dual-modality imager combining optoacoustic tomography (OAT) and laser ultrasound tomography (UST) using computer models followed by experimental validation. The system designed for preclinical biomedical research can concurrently yield images depicting both the absorbed optical energy density and acoustic properties (speed of sound) of an object. In our design of the UST imager, we seek to replace conventional electrical generation of ultrasound waves by laser-induced ultrasound (LU). While earlier studies yielded encouraging results [Manohar, et al., Appl. Phys. Lett, 131911, 2007], they were limited to two-dimensional (2D) geometries. In this work, we conduct computer-simulation studies to investigate different designs for the 3D LU UST imager. The number and location of the laser ultrasound emitters, which are constrained to reside on the cylindrical surface opposite to the arc of detectors, are optimized. In addition to the system parameters, an iterative image reconstruction algorithm was optimized. We demonstrate that high quality volumetric maps of the speed of sound can be reconstructed when only 32 emitters and 128 receiving transducers are employed to record time-of-flight data at 360 tomographic view angles. The implications of the proposed system for small animal and breast-cancer imaging are discussed.

  14. Observations of sound-speed fluctuations on the New Jersey continental shelf in the summer of 2006.

    PubMed

    Colosi, John A; Duda, Timothy F; Lin, Ying-Tsong; Lynch, James F; Newhall, Arthur E; Cornuelle, Bruce D

    2012-02-01

    Environmental sensors moored on the New Jersey continental shelf tracked constant density surfaces (isopycnals) for 35 days in the summer of 2006. Sound-speed fluctuations from internal-wave vertical isopycnal displacements and from temperature/salinity variability along isopycnals (spiciness) are analyzed using frequency spectra and vertical covariance functions. Three varieties of internal waves are studied: Diffuse broadband internal waves (akin to waves fitting the deep water Garrett/Munk spectrum), internal tides, and, to a lesser extent, nonlinear internal waves. These internal-wave contributions are approximately distinct in the frequency domain. It is found that in the main thermocline spicy thermohaline structure dominates the root mean square sound-speed variability, with smaller contributions coming from (in order) nonlinear internal waves, diffuse internal waves, and internal tides. The frequency spectra of internal-wave displacements and of spiciness have similar form, likely due to the advection of variable-spiciness water masses by horizontal internal-wave currents, although there are technical limitations to the observations at high frequency. In the low-frequency, internal-wave band the internal-wave spectrum follows frequency to the -1.81 power, whereas the spice spectrum shows a -1.73 power. Mode spectra estimated via covariance methods show that the diffuse internal-wave spectrum has a smaller mode bandwidth than Garrett/Munk and that the internal tide has significant energy in modes one through three.

  15. Sound Speed Structure of the Northeast Atlantic Ocean in Summer 1973 during the SQUARE DEAL Exercise

    DTIC Science & Technology

    1980-03-01

    from the CHUIJRCH GABBRO the similar periodicity in the spectral Exercise (Fenner and Bucca, 1973) and ambient noise intensity observed at the NORLANT...Permanent International pour Fenner, D.F. and P.J. Bucca (1973). I’Exploration de Ia Mer,.v. 157, July, CHURCH GABBRO Sound Velocity Analysis p. 173-183...target. MIW: MediterrAnfian Intermediate WaLer QCIRCH GABBRO - A LRAPP acoustic/envi- (high salinity). ronmental exercise in the Cayman Trough and

  16. What Makes Speech Sound Fluent? The Contributions of Pauses, Speed and Repairs

    ERIC Educational Resources Information Center

    Bosker, Hans Rutger; Pinget, Anne-France; Quene, Hugo; Sanders, Ted; de Jong, Nivja H.

    2013-01-01

    The oral fluency level of an L2 speaker is often used as a measure in assessing language proficiency. The present study reports on four experiments investigating the contributions of three fluency aspects (pauses, speed and repairs) to perceived fluency. In Experiment 1 untrained raters evaluated the oral fluency of L2 Dutch speakers. Using…

  17. Imaging hair cell transduction at the speed of sound: dynamic behavior of mammalian stereocilia.

    PubMed

    Fridberger, Anders; Tomo, Igor; Ulfendahl, Mats; Boutet de Monvel, Jacques

    2006-02-07

    The cochlea contains two types of sensory cells, the inner and outer hair cells. Sound-evoked deflection of outer hair cell stereocilia leads to fast force production that will enhance auditory sensitivity up to 1,000-fold. In contrast, inner hair cells are thought to have a purely receptive function. Deflection of their stereocilia produces receptor potentials, transmitter release, and action potentials in the auditory nerve. Here, we describe a method for rapid confocal imaging. The method was used to image stereocilia during simultaneous sound stimulation in an in vitro preparation of the guinea pig cochlea. We show that inner hair cell stereocilia move because they interact with the fluid surrounding the hair bundles, but stereocilia deflection occurs at a different phase of the stimulus than is generally expected. In outer hair cells, stereocilia deflections were approximately 1/3 of the reticular lamina displacement. Smaller deflections were found in inner hair cells. The ratio between stereocilia deflection and reticular lamina displacement is important for auditory function, because it determines the stimulus applied to transduction channels. The low ratio measured here suggests that amplification of hair-bundle movements may be necessary in vivo to preserve transduction fidelity at low stimulus levels. In the case of the inner hair cells, this finding would represent a departure from traditional views on their function.

  18. Protons at the speed of sound: Predicting specific biological signaling from physics

    PubMed Central

    Fichtl, Bernhard; Shrivastava, Shamit; Schneider, Matthias F.

    2016-01-01

    Local changes in pH are known to significantly alter the state and activity of proteins and enzymes. pH variations induced by pulses propagating along soft interfaces (e.g. membranes) would therefore constitute an important pillar towards a physical mechanism of biological signaling. Here we investigate the pH-induced physical perturbation of a lipid interface and the physicochemical nature of the subsequent acoustic propagation. Pulses are stimulated by local acidification and propagate – in analogy to sound – at velocities controlled by the interface’s compressibility. With transient local pH changes of 0.6 directly observed at the interface and velocities up to 1.4 m/s this represents hitherto the fastest protonic communication observed. Furthermore simultaneously propagating mechanical and electrical changes in the lipid interface are detected, exposing the thermodynamic nature of these pulses. Finally, these pulses are excitable only beyond a threshold for protonation, determined by the pKa of the lipid head groups. This protonation-transition plus the existence of an enzymatic pH-optimum offer a physical basis for intra- and intercellular signaling via sound waves at interfaces, where not molecular structure and mechano-enyzmatic couplings, but interface thermodynamics and thermodynamic transitions are the origin of the observations. PMID:27216038

  19. Protons at the speed of sound: Predicting specific biological signaling from physics

    NASA Astrophysics Data System (ADS)

    Fichtl, Bernhard; Shrivastava, Shamit; Schneider, Matthias F.

    2016-05-01

    Local changes in pH are known to significantly alter the state and activity of proteins and enzymes. pH variations induced by pulses propagating along soft interfaces (e.g. membranes) would therefore constitute an important pillar towards a physical mechanism of biological signaling. Here we investigate the pH-induced physical perturbation of a lipid interface and the physicochemical nature of the subsequent acoustic propagation. Pulses are stimulated by local acidification and propagate – in analogy to sound – at velocities controlled by the interface’s compressibility. With transient local pH changes of 0.6 directly observed at the interface and velocities up to 1.4 m/s this represents hitherto the fastest protonic communication observed. Furthermore simultaneously propagating mechanical and electrical changes in the lipid interface are detected, exposing the thermodynamic nature of these pulses. Finally, these pulses are excitable only beyond a threshold for protonation, determined by the pKa of the lipid head groups. This protonation-transition plus the existence of an enzymatic pH-optimum offer a physical basis for intra- and intercellular signaling via sound waves at interfaces, where not molecular structure and mechano-enyzmatic couplings, but interface thermodynamics and thermodynamic transitions are the origin of the observations.

  20. Imaging hair cell transduction at the speed of sound: Dynamic behavior of mammalian stereocilia

    PubMed Central

    Fridberger, Anders; Tomo, Igor; Ulfendahl, Mats; Boutet de Monvel, Jacques

    2006-01-01

    The cochlea contains two types of sensory cells, the inner and outer hair cells. Sound-evoked deflection of outer hair cell stereocilia leads to fast force production that will enhance auditory sensitivity up to 1, 000-fold. In contrast, inner hair cells are thought to have a purely receptive function. Deflection of their stereocilia produces receptor potentials, transmitter release, and action potentials in the auditory nerve. Here, we describe a method for rapid confocal imaging. The method was used to image stereocilia during simultaneous sound stimulation in an in vitro preparation of the guinea pig cochlea. We show that inner hair cell stereocilia move because they interact with the fluid surrounding the hair bundles, but stereocilia deflection occurs at a different phase of the stimulus than is generally expected. In outer hair cells, stereocilia deflections were ≈1/3 of the reticular lamina displacement. Smaller deflections were found in inner hair cells. The ratio between stereocilia deflection and reticular lamina displacement is important for auditory function, because it determines the stimulus applied to transduction channels. The low ratio measured here suggests that amplification of hair-bundle movements may be necessary in vivo to preserve transduction fidelity at low stimulus levels. In the case of the inner hair cells, this finding would represent a departure from traditional views on their function. PMID:16446441

  1. Protons at the speed of sound: Predicting specific biological signaling from physics.

    PubMed

    Fichtl, Bernhard; Shrivastava, Shamit; Schneider, Matthias F

    2016-05-24

    Local changes in pH are known to significantly alter the state and activity of proteins and enzymes. pH variations induced by pulses propagating along soft interfaces (e.g. membranes) would therefore constitute an important pillar towards a physical mechanism of biological signaling. Here we investigate the pH-induced physical perturbation of a lipid interface and the physicochemical nature of the subsequent acoustic propagation. Pulses are stimulated by local acidification and propagate - in analogy to sound - at velocities controlled by the interface's compressibility. With transient local pH changes of 0.6 directly observed at the interface and velocities up to 1.4 m/s this represents hitherto the fastest protonic communication observed. Furthermore simultaneously propagating mechanical and electrical changes in the lipid interface are detected, exposing the thermodynamic nature of these pulses. Finally, these pulses are excitable only beyond a threshold for protonation, determined by the pKa of the lipid head groups. This protonation-transition plus the existence of an enzymatic pH-optimum offer a physical basis for intra- and intercellular signaling via sound waves at interfaces, where not molecular structure and mechano-enyzmatic couplings, but interface thermodynamics and thermodynamic transitions are the origin of the observations.

  2. Modeling unsteady sound refraction by coherent structures in a high-speed jet

    NASA Astrophysics Data System (ADS)

    Kan, Pinqing; Lewalle, Jacques

    2011-11-01

    We construct a visual model for the unsteady refraction of sound waves from point sources in a Ma = 0.6 jet. The mass and inviscid momentum equations give an equation governing acoustic fluctuations, including anisotropic propagation, attenuation and sources; differences with Lighthill's equation will be discussed. On this basis, the theory of characteristics gives canonical equations for the acoustic paths from any source into the far field. We model a steady mean flow in the near-jet region including the potential core and the mixing region downstream of its collapse, and model the convection of coherent structures as traveling wave perturbations of this mean flow. For a regular distribution of point sources in this region, we present a visual rendition of fluctuating distortion, lensing and deaf spots from the viewpoint of a far-field observer. Supported in part by AFOSR Grant FA-9550-10-1-0536 and by a Syracuse University Graduate Fellowship.

  3. Measurement of the speed of sound in trabecular bone by using a time reversal acoustics focusing system

    NASA Astrophysics Data System (ADS)

    Lee, Kang Il; Choi, Bok Kyoung

    2014-10-01

    A new method for measuring the speed of sound (SOS) in trabecular bone by using a time reversal acoustics (TRA) focusing system was proposed and validated with measurements obtained by using the conventional pulse-transmission technique. The SOS measured in 14 bovine femoral trabecular bone samples by using the two methods was highly correlated each other, although the SOS measured by using the TRA focusing system was slightly lower by an average of 2.2 m/s. The SOS measured by using the two methods showed high correlation coefficients of r = 0.92 with the apparent bone density, consistent with the behavior in human trabecular bone in vitro. These results prove the efficacy of the new method based on the principle of TRA to measure the SOS in trabecular bone.

  4. Target-depth estimation in active sonar: Cramer-Rao bounds for a bilinear sound-speed profile.

    PubMed

    Mours, Alexis; Ioana, Cornel; Mars, Jérôme I; Josso, Nicolas F; Doisy, Yves

    2016-09-01

    This paper develops a localization method to estimate the depth of a target in the context of active sonar, at long ranges. The target depth is tactical information for both strategy and classification purposes. The Cramer-Rao lower bounds for the target position as range and depth are derived for a bilinear profile. The influence of sonar parameters on the standard deviations of the target range and depth are studied. A localization method based on ray back-propagation with a probabilistic approach is then investigated. Monte-Carlo simulations applied to a summer Mediterranean sound-speed profile are performed to evaluate the efficiency of the estimator. This method is finally validated on data in an experimental tank.

  5. Indirect Measurement Of Nitrogen In A Multi-Component Gas By Measuring The Speed Of Sound At Two States Of The Gas.

    DOEpatents

    Morrow, Thomas B.; Behring, II, Kendricks A.

    2004-10-12

    A methods of indirectly measuring the nitrogen concentration in a gas mixture. The molecular weight of the gas is modeled as a function of the speed of sound in the gas, the diluent concentrations in the gas, and constant values, resulting in a model equation. Regression analysis is used to calculate the constant values, which can then be substituted into the model equation. If the speed of sound in the gas is measured at two states and diluent concentrations other than nitrogen (typically carbon dioxide) are known, two equations for molecular weight can be equated and solved for the nitrogen concentration in the gas mixture.

  6. Speed of sound in solid molecular hydrogen-deuterium: Quantum Molecular Dynamics Approximation

    NASA Astrophysics Data System (ADS)

    Guerrero, Carlo Luis; Perlado, Jose Manuel

    2016-05-01

    Uniformity of the solid layer is one of the critical points for an efficient ignition of the Deuterium-Tritium (DT) target. During the compression process this layer, perturbations grow as the Rayleigh-Taylor instability. Knowing the mechanical properties of this layer and its thermo-mechanical limits is necessary if we want to control or to minimize these instabilities. In this work we have used a simplified approach, replacing the DT ice system with a mixture of hydrogen-deuterium (HD) because beta decay of tritium complicates the analysis in the former case. Through simulation with ab initio methods we have calculated the elastic constants, the bulk modulus and sound velocity for hydrogen isotopes in solid molecular state. In this work we present the results for hydrogen-deuterium mixtures 50%-50%, at 15 K and with a compression which covers the range of 1 to 15 GPa. This system is interesting for study the early stages of the dynamic compression and provides conditions that are close to the manufacture of DT target in inertial confinement fusion. Discontinuities in the curve that have been observed on pure hydrogen, which are associated with phase transitions and the phase hysteresis.

  7. Deep ocean sound speed characteristics passively derived from the ambient acoustic noise field

    NASA Astrophysics Data System (ADS)

    Evers, L. G.; Wapenaar, K.; Heaney, K. D.; Snellen, M.

    2017-02-01

    The propagation of acoustic waves in the ocean strongly depends on the temperature. Low frequency acoustic waves can penetrate the ocean down to depths where few in-situ measurements are available. It is therefore attractive to obtain a measure of the deep ocean temperature from acoustic waves. The latter is especially true if the ambient acoustic noise field can be used instead of deterministic transient signals. In this study the acoustic velocity, and hence the temperature, is derived in an interferometric approach from hydrophone array recordings. The arrays were separated by over 125 km, near Ascension Island in the Atlantic Ocean, at a depth of 850m. Furthermore, the dispersive characteristics of the deep ocean sound channel are resolved based on the retrieved lag times for different modes. In addition, it is shown how the resolution of the interferometric approach can be increased by cross correlating array beams rather than recordings from single-sensor pairs. The observed acoustic lag times between the arrays corresponds well to modeled values, based on full-wave modeling through best-known oceanic models.

  8. Use of a new high-speed digital data acquisition system in airborne ice-sounding

    USGS Publications Warehouse

    Wright, David L.; Bradley, Jerry A.; Hodge, Steven M.

    1989-01-01

    A high-speed digital data acquisition and signal averaging system for borehole, surface, and airborne radio-frequency geophysical measurements was designed and built by the US Geological Survey. The system permits signal averaging at rates high enough to achieve significant signal-to-noise enhancement in profiling, even in airborne applications. The first field use of the system took place in Greenland in 1987 for recording data on a 150 by 150-km grid centered on the summit of the Greenland ice sheet. About 6000-line km were flown and recorded using the new system. The data can be used to aid in siting a proposed scientific corehole through the ice sheet.

  9. Substituting an Inexpensive Function Generator for the Pulsed Laser in the Experiment "Laser Measurement of the Speed of Sound in Gases"

    ERIC Educational Resources Information Center

    Epstein, Mark G.; Laszlo, Matthew W.; Mayer, Steven G.

    2010-01-01

    We present an adaptation to an experiment previously published in this "Journal". The experiment was designed to determine the heat capacity ratios of gases by measuring the speed of sound using a modified Kundt's tube. The experiment yielded excellent results for all of the gases and gas mixtures measured. Although elegant in its simplicity, it…

  10. 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.

  11. 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.

  12. Magnitude of speed of sound aberration corrections for ultrasound image guided radiotherapy for prostate and other anatomical sites

    SciTech Connect

    Fontanarosa, Davide; Meer, Skadi van der; Bloemen-van Gurp, Esther; Stroian, Gabriela; Verhaegen, Frank

    2012-08-15

    Purpose: The purpose of this work is to assess the magnitude of speed of sound (SOS) aberrations in three-dimensional ultrasound (US) imaging systems in image guided radiotherapy. The discrepancy between the fixed SOS value of 1540 m/s assumed by US systems in human soft tissues and its actual nonhomogeneous distribution in patients produces small but systematic errors of up to a few millimeters in the positions of scanned structures. Methods: A correction, provided by a previously published density-based algorithm, was applied to a set of five prostate, five liver, and five breast cancer patients. The shifts of the centroids of target structures and the change in shape were evaluated. Results: After the correction the prostate cases showed shifts up to 3.6 mm toward the US probe, which may explain largely the reported positioning discrepancies in the literature on US systems versus other imaging modalities. Liver cases showed the largest changes in volume of the organ, up to almost 9%, and shifts of the centroids up to more than 6 mm either away or toward the US probe. Breast images showed systematic small shifts of the centroids toward the US probe with a maximum magnitude of 1.3 mm. Conclusions: The applied correction in prostate and liver cancer patients shows positioning errors of several mm due to SOS aberration; the errors are smaller in breast cancer cases, but possibly becoming more important when breast tissue thickness increases.

  13. The derivative of a waveguide acoustic field with respect to a three-dimensional sound speed perturbation

    NASA Astrophysics Data System (ADS)

    Thode, Aaron

    2004-06-01

    Semianalytic expressions are derived for the first-order derivative of a pressure field in a laterally homogeneous 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 Green's functions, weighted by an environmental parameter basis function, with the Green's 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 an arbitrary sound-speed perturbation. To illustrate the formulas, a simple sensitivity study is presented that explores under what circumstances three-dimensional plane-wave and cylindrical perturbations produce non-negligible horizontal refraction effects, for a fixed source/receiver geometry. Other potential applications of these formulas include benchmarking three-dimensional propagation codes, and computing Cramer-Rao bounds for three-dimensional environmental parameter estimates, including internal wave components.

  14. Gene-dietary fat interaction, bone mineral density and bone speed of sound in Children: a twin study in China

    PubMed Central

    Huang, Tao; Liu, Huijuan; Zhao, Wei; Li, Ji; Wang, Youfa

    2015-01-01

    Scope Dietary fat correlates with bone mineral density (BMD). We tested the association between fat intake and BMD, and tested if fat intake modified the degree of genetic influence on BMD and bone speed of sound (SOS). Methods and results We included 622 twins aged 7–15 y from South China. Data on anthropometry, dietary intake, BMD, and SOS were collected. Quantitative genetic analyses of structural equation models were fit using the Mx statistical package. The within-pair intra-class correlations (ICC) for BMD in DZ twins were nearly half of that for MZ twins (ICC=0.39 vs 0.70). The heritability of BMD and SOS were 71% and 79%. Phenotypic correlation between fat intake and SOS was significant (r=−0.19, p=0.04). SOS was negatively correlated with fat intake in boys (r=−0.11, p=0.05), but not in girls. Full Cholesky decomposition models showed SOS has a strong genetic correlation with fat intake (rA =−0.88, 95% CI=−0.94, 0.01); the environmental correlation between fat intake and SOS was weak (rE =−0.04, 95% CI=−0.20, 0.13). Fat intake modified the additive genetic effects on BMD. Conclusion Genetic factors explained 71% and 79% of individual variance in BMD and SOS, respectively. Low fat intake counteracts genetic predisposition to low BMD. PMID:25546604

  15. Women's age and embryo developmental speed accurately predict clinical pregnancy after single vitrified-warmed blastocyst transfer.

    PubMed

    Kato, Keiichi; Ueno, Satoshi; Yabuuchi, Akiko; Uchiyama, Kazuo; Okuno, Takashi; Kobayashi, Tamotsu; Segawa, Tomoya; Teramoto, Shokichi

    2014-10-01

    The aim of this study was to establish a simple, objective blastocyst grading system using women's age and embryo developmental speed to predict clinical pregnancy after single vitrified-warmed blastocyst transfer. A 6-year retrospective cohort study was conducted in a private infertility centre. A total of 7341 single vitrified-armed blastocyst transfer cycles were included, divided into those carried out between 2006 and 2011 (6046 cycles) and 2012 (1295 cycles). Clinical pregnancy rate, ongoing pregnancy rate and delivery rates were stratified by women's age (<35, 35-37, 38-39, 40-41, 42-45 years) and time to blastocyst expansion (<120, 120-129, 130-139, 140-149, >149 h) as embryo developmental speed. In all the age groups, clinical pregnancy rate, ongoing pregnancy rate and delivery rates decreased as the embryo developmental speed decreased (P < 0.0001). A simple five-grade score based on women's age and embryo developmental speed was determined by actual clinical pregnancy rates observed in the 2006-2011 cohort. Subsequently, the novel grading score was validated in the 2012 cohort (1295 cycles), finding an excellent association. In conclusion, we established a novel blastocyst grading system using women's age and embryo developmental speed as objective parameters.

  16. 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.

  17. Repeatable, accurate, and high speed multi-level programming of memristor 1T1R arrays for power efficient analog computing applications

    NASA Astrophysics Data System (ADS)

    Merced-Grafals, Emmanuelle J.; Dávila, Noraica; Ge, Ning; Williams, R. Stanley; Strachan, John Paul

    2016-09-01

    Beyond use as high density non-volatile memories, memristors have potential as synaptic components of neuromorphic systems. We investigated the suitability of tantalum oxide (TaOx) transistor-memristor (1T1R) arrays for such applications, particularly the ability to accurately, repeatedly, and rapidly reach arbitrary conductance states. Programming is performed by applying an adaptive pulsed algorithm that utilizes the transistor gate voltage to control the SET switching operation and increase programming speed of the 1T1R cells. We show the capability of programming 64 conductance levels with <0.5% average accuracy using 100 ns pulses and studied the trade-offs between programming speed and programming error. The algorithm is also utilized to program 16 conductance levels on a population of cells in the 1T1R array showing robustness to cell-to-cell variability. In general, the proposed algorithm results in approximately 10× improvement in programming speed over standard algorithms that do not use the transistor gate to control memristor switching. In addition, after only two programming pulses (an initialization pulse followed by a programming pulse), the resulting conductance values are within 12% of the target values in all cases. Finally, endurance of more than 106 cycles is shown through open-loop (single pulses) programming across multiple conductance levels using the optimized gate voltage of the transistor. These results are relevant for applications that require high speed, accurate, and repeatable programming of the cells such as in neural networks and analog data processing.

  18. A speed of sound aberration correction algorithm for curvilinear ultrasound transducers in ultrasound-based image-guided radiotherapy.

    PubMed

    Fontanarosa, Davide; Pesente, Silvia; Pascoli, Francesco; Ermacora, Denis; Rumeileh, Imad Abu; Verhaegen, Frank

    2013-03-07

    Conventional ultrasound (US) devices use the time of flight (TOF) of reflected US pulses to calculate distances inside the scanned tissues and thus create images. The speed of sound (SOS) is assumed to be constant in all human soft tissues at a generally accepted average value of 1540 m s(-1). This assumption is a source of systematic errors up to several millimeters and of image distortion in quantitative US imaging. In this work, an extension of a method recently published by Fontanarosa et al (2011 Med. Phys. 38 2665-73) is presented: the aim is to correct SOS aberrations in three-dimensional (3D) US images in those cases where a spatially co-registered computerized tomography (CT) scan is also available; the algorithm is then applicable to a more general case where the lines of view (LOV) of the US device are not necessarily parallel and coplanar, thus allowing correction also for US transducers other than linear. The algorithm was applied on a multi-modality pelvic US phantom, scanned through three different liquid layers on top of the phantom with different SOS values; the results show that the correction restores a better match between the CT and the US images, reducing the differences to sub-millimeter agreement. Fifteen clinical cases of prostate cancer patients were also investigated: the SOS corrections of prostate centroids were on average +3.1 mm (max + 4.9 mm-min + 1.3 mm). This is in excellent agreement with reports in the literature on differences between measured prostate positions by US and other techniques, where often the discrepancy was attributed to other causes.

  19. A speed of sound aberration correction algorithm for curvilinear ultrasound transducers in ultrasound-based image-guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Fontanarosa, Davide; Pesente, Silvia; Pascoli, Francesco; Ermacora, Denis; Abu Rumeileh, Imad; Verhaegen, Frank

    2013-03-01

    Conventional ultrasound (US) devices use the time of flight (TOF) of reflected US pulses to calculate distances inside the scanned tissues and thus create images. The speed of sound (SOS) is assumed to be constant in all human soft tissues at a generally accepted average value of 1540 m s-1. This assumption is a source of systematic errors up to several millimeters and of image distortion in quantitative US imaging. In this work, an extension of a method recently published by Fontanarosa et al (2011 Med. Phys. 38 2665-73) is presented: the aim is to correct SOS aberrations in three-dimensional (3D) US images in those cases where a spatially co-registered computerized tomography (CT) scan is also available; the algorithm is then applicable to a more general case where the lines of view (LOV) of the US device are not necessarily parallel and coplanar, thus allowing correction also for US transducers other than linear. The algorithm was applied on a multi-modality pelvic US phantom, scanned through three different liquid layers on top of the phantom with different SOS values; the results show that the correction restores a better match between the CT and the US images, reducing the differences to sub-millimeter agreement. Fifteen clinical cases of prostate cancer patients were also investigated: the SOS corrections of prostate centroids were on average +3.1 mm (max + 4.9 mm-min + 1.3 mm). This is in excellent agreement with reports in the literature on differences between measured prostate positions by US and other techniques, where often the discrepancy was attributed to other causes.

  20. Seafloor sound-speed profile characterization with non-parallel layering by the image source method: Application to CLUTTER'09 campaign data.

    PubMed

    Pinson, Samuel; Holland, Charles W

    2016-08-01

    The image source method was originally developed to estimate sediment sound speed as a function of depth assuming plane-layered sediments. Recently, the technique was extended to treat dipping, i.e., non-parallel layers and was tested using synthetic data. Here, the technique is applied to measured reflection data with dipping layers and mud volcanoes. The data were collected with an autonomous underwater vehicle towing a source (1600-3500 Hz) and a horizontal array of hydrophones. Data were collected every 3 m criss-crossing an area about 1 km(2). The results provide a combination of two-dimensional sections of the sediment sound-speeds plotted in a three-dimensional picture.

  1. Measurement of the Frequency Dependence of the Sound Speed and Attenuation of Seafloor Sands From 1 to 400 kHz

    DTIC Science & Technology

    2010-07-01

    Seismic Exploration Synthesis ( OASES ) mod- eling package [10] to reduce the interference from multipath signals on sound-speed and attenuation...location using the OASES model as a forward model. The deconvolution analysis was performed by deconvolving each data trace with a source wavelet...based analysis was applied to a simulated data set generated by a full waveform model ( OASES ) for a setting similar to that in which the actual data

  2. 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.

  3. Dynamics of High Sound-Speed Metal Confiners Driven By Non-Ideal High-Explosive Detonation

    DOE PAGES

    Short, Mark; Jackson, Scott I.

    2015-01-23

    Here, the results of 14 tests examining the behavior of aluminum (Al) conifners driven by non-ideal ANFO detonation in a cylinder test configuration are presented. In each test, the measured detonation phase velocity is slower than the aluminum sound speed. Thus, in the detonation reference frame, the ow in the Al is both shockless and subsonic. The tests involve: 3-inch inner diameter (ID) cylinders with Al wall thicknesses of 1/4, 3/8, 1/2, 1 and 2 inches; a 4-inch ID cylinder with a 1/2-inch Al wall thickness; and 6-inch ID cylinders with Al wall thicknesses of 1/2, 1 and 2 inches.more » The ANFO detonation velocity is seen to increase with increasing wall thickness for both the 3- and 6-inch ID tests, with no limiting velocity reached for the wall thicknesses used. The motion of the outer Al wall due to precursor elastic waves in the Al running ahead of the detonation is also measured at various axial locations along the cylinders. It is found that the magnitude of the outer wall motion due to the precursor elastic waves is small, while the associated wall motion is unsteady and decays in amplitude as the elastic disturbances move further ahead of the detonation front. The variations in the expansion history of the main outer wall motion of the cylinders are presented for increasing wall thickness at fixed ID, and for increasing cylinder inner diameter at a fixed wall thickness. Finally, we also explore the existence of a geometric similarity scaling of the wall expansion history for three geometrically scaled tests (3- and 6-inch ID cylinders with 1/4- and 1/2-inch walls respectively, 3- and 6-inch ID cylinders with 1/2- and 1-inch walls and 3- and 6-inch ID cylinders with 1- and 2-inch walls respectively). We find that the wall velocity histories for each of the three scaled tests, when plotted directly against time relative to start of main motion of the wall, are similar over a certain range of wall velocities without any geometric based rescaling in time

  4. Dynamics of High Sound-Speed Metal Confiners Driven By Non-Ideal High-Explosive Detonation

    SciTech Connect

    Short, Mark; Jackson, Scott I.

    2015-01-23

    Here, the results of 14 tests examining the behavior of aluminum (Al) conifners driven by non-ideal ANFO detonation in a cylinder test configuration are presented. In each test, the measured detonation phase velocity is slower than the aluminum sound speed. Thus, in the detonation reference frame, the ow in the Al is both shockless and subsonic. The tests involve: 3-inch inner diameter (ID) cylinders with Al wall thicknesses of 1/4, 3/8, 1/2, 1 and 2 inches; a 4-inch ID cylinder with a 1/2-inch Al wall thickness; and 6-inch ID cylinders with Al wall thicknesses of 1/2, 1 and 2 inches. The ANFO detonation velocity is seen to increase with increasing wall thickness for both the 3- and 6-inch ID tests, with no limiting velocity reached for the wall thicknesses used. The motion of the outer Al wall due to precursor elastic waves in the Al running ahead of the detonation is also measured at various axial locations along the cylinders. It is found that the magnitude of the outer wall motion due to the precursor elastic waves is small, while the associated wall motion is unsteady and decays in amplitude as the elastic disturbances move further ahead of the detonation front. The variations in the expansion history of the main outer wall motion of the cylinders are presented for increasing wall thickness at fixed ID, and for increasing cylinder inner diameter at a fixed wall thickness. Finally, we also explore the existence of a geometric similarity scaling of the wall expansion history for three geometrically scaled tests (3- and 6-inch ID cylinders with 1/4- and 1/2-inch walls respectively, 3- and 6-inch ID cylinders with 1/2- and 1-inch walls and 3- and 6-inch ID cylinders with 1- and 2-inch walls respectively). We find that the wall velocity histories for each of the three scaled tests, when plotted directly against time relative to start of main motion of the wall, are similar over a certain range of wall velocities without any geometric based rescaling in time. The

  5. Repeatable, accurate, and high speed multi-level programming of memristor 1T1R arrays for power efficient analog computing applications.

    PubMed

    Merced-Grafals, Emmanuelle J; Dávila, Noraica; Ge, Ning; Williams, R Stanley; Strachan, John Paul

    2016-09-09

    Beyond use as high density non-volatile memories, memristors have potential as synaptic components of neuromorphic systems. We investigated the suitability of tantalum oxide (TaOx) transistor-memristor (1T1R) arrays for such applications, particularly the ability to accurately, repeatedly, and rapidly reach arbitrary conductance states. Programming is performed by applying an adaptive pulsed algorithm that utilizes the transistor gate voltage to control the SET switching operation and increase programming speed of the 1T1R cells. We show the capability of programming 64 conductance levels with <0.5% average accuracy using 100 ns pulses and studied the trade-offs between programming speed and programming error. The algorithm is also utilized to program 16 conductance levels on a population of cells in the 1T1R array showing robustness to cell-to-cell variability. In general, the proposed algorithm results in approximately 10× improvement in programming speed over standard algorithms that do not use the transistor gate to control memristor switching. In addition, after only two programming pulses (an initialization pulse followed by a programming pulse), the resulting conductance values are within 12% of the target values in all cases. Finally, endurance of more than 10(6) cycles is shown through open-loop (single pulses) programming across multiple conductance levels using the optimized gate voltage of the transistor. These results are relevant for applications that require high speed, accurate, and repeatable programming of the cells such as in neural networks and analog data processing.

  6. Speed of sound measurements and mixing characterization of underexpanded fuel jets with supercritical reservoir condition using laser-induced thermal acoustics

    NASA Astrophysics Data System (ADS)

    Baab, S.; Förster, F. J.; Lamanna, G.; Weigand, B.

    2016-11-01

    The four-wave mixing technique laser-induced thermal acoustics was used to measure the local speed of sound in the farfield zone of extremely underexpanded jets. N-hexane at supercritical injection temperature and pressure (supercritical reservoir condition) was injected into quiescent subcritical nitrogen (with respect to the injectant). The technique's capability to quantify the nonisothermal, turbulent mixing zone of small-scale jets is demonstrated for the first time. Consistent radially resolved speed of sound profiles are presented for different axial positions and varying injection temperatures. Furthermore, an adiabatic mixing model based on nonideal thermodynamic properties is presented to extract mixture composition and temperature from the experimental speed of sound data. High fuel mass fractions of up to 94 % are found for the centerline at an axial distance of 55 diameters from the nozzle followed by a rapid decay in axial direction. This is attributed to a supercritical fuel state at the nozzle exit resulting in the injection of a high-density fluid. The obtained concentration data are complemented by existing measurements and collapsed in a similarity law. It allows for mixture prediction of underexpanded jets with supercritical reservoir condition provided that nonideal thermodynamic behavior is considered for the nozzle flow. Specifically, it is shown that the fuel concentration in the farfield zone is very sensitive to the thermodynamic state at the nozzle exit. Here, a transition from supercritical fluid to subcritical vapor state results in strongly varying fuel concentrations, which implies high impact on the mixture formation and, consequently, on the combustion characteristics.

  7. Analytical and numerical prediction of harmonic sound power in the inlet of aero-engines with emphasis on transonic rotation speeds

    NASA Astrophysics Data System (ADS)

    Lewy, Serge; Polacsek, Cyril; Barrier, Raphael

    2014-12-01

    Tone noise radiated through the inlet of a turbofan is mainly due to rotor-stator interactions at subsonic regimes (approach flight), and to the shock waves attached to each blade at supersonic helical tip speeds (takeoff). The axial compressor of a helicopter turboshaft engine is transonic as well and can be studied like turbofans at takeoff. The objective of the paper is to predict the sound power at the inlet radiating into the free field, with a focus on transonic conditions because sound levels are much higher. Direct numerical computation of tone acoustic power is based on a RANS (Reynolds averaged Navier-Stokes) solver followed by an integration of acoustic intensity over specified inlet cross-sections, derived from Cantrell and Hart equations (valid in irrotational flows). In transonic regimes, sound power decreases along the intake because of nonlinear propagation, which must be discriminated from numerical dissipation. This is one of the reasons why an analytical approach is also suggested. It is based on three steps: (i) appraisal of the initial pressure jump of the shock waves; (ii) 2D nonlinear propagation model of Morfey and Fisher; (iii) calculation of the sound power of the 3D ducted acoustic field. In this model, all the blades are assumed to be identical such that only the blade passing frequency and its harmonics are predicted (like in the present numerical simulations). However, transfer from blade passing frequency to multiple pure tones can be evaluated in a fourth step through a statistical analysis of irregularities between blades. Interest of the analytical method is to provide a good estimate of nonlinear acoustic propagation in the upstream duct while being easy and fast to compute. The various methods are applied to two turbofan models, respectively in approach (subsonic) and takeoff (transonic) conditions, and to a Turbomeca turboshaft engine (transonic case). The analytical method in transonic appears to be quite reliable by comparison

  8. Optical and thermodynamic properties of MgO from radiative shock temperature and sound speed measurements on samples preheated to 2300 K

    NASA Astrophysics Data System (ADS)

    Fatýanov, O. V.; Asimow, P. D.

    2013-12-01

    Thermodynamic properties of MgO, one of the major end-members of deep planetary interiors, play a significant role in the processes inside the Earth's lower mantle. Of particular importance in geophysics and geochemistry is the MgO melting behavior at high pressure. Despite considerable theoretical and experimental efforts over decades, it remains essentially unknown. The melting temperature predictions for MgO at 135 GPa, the Earth's core-mantle boundary pressure, range from 5 to 9 kK. In a continuous effort to resolve this inconsistency and to probe the P-T region previously unexplored, we developed a technique for radiative shock temperature measurements in single-crystal MgO preheated to 2300 K. Large ventilated Mo capsules were employed to hold ~20 mm long MgO crystals with controlled longitudinal thermal gradients. These hot targets were impacted by 0.8 mm thick Ta flyers launched at 6.5 to 7.5 km/s on the Caltech two-stage light-gas gun. Six spectral radiance histories from MgO shock front were recorded in every shot with 3 ns time resolution over 440-750 nm or 500-830 nm spectral range. The majority of our experiments showed smooth pressure dependence of MgO shock temperature and sound speed consistent with the solid phase at 197-243 GPa. Although most observed temperatures are ~700 K lower and sound speeds ~1 km/s higher than the model predictions, the pressure slopes for both parameters are in close agreement with those calculated for the solid phase. Unconfirmed data from a single experiment at 239 GPa and 8.3 kK showed correlated temperature and sound speed anomalies (both values lower than expected) that may be explained by partial melting. Our past and recent data on shock-compressed preheated MgO suggest its melting curve above 200 GPa is higher than the extrapolation of the experiments of Zerr & Boehler or the theoretical calculation by Strachan et. al. These results, features of shock experiments with 2300 K pre-heat temperatures, data analysis

  9. 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.

  10. Analyzing sound speed fluctuations in shallow water from group-velocity versus phase-velocity data representation.

    PubMed

    Roux, Philippe; Kuperman, W A; Cornuelle, Bruce D; Aulanier, Florian; Hodgkiss, W S; Song, Hee Chun

    2013-04-01

    Data collected over more than eight consecutive hours between two source-receiver arrays in a shallow water environment are analyzed through the physics of the waveguide invariant. In particular, the use of vertical arrays on both the source and receiver sides provides source and receiver angles in addition to travel-times associated with a set of eigenray paths in the waveguide. From the travel-times and the source-receiver angles, the eigenrays are projected into a group-velocity versus phase-velocity (Vg-Vp) plot for each acquisition. The time evolution of the Vg-Vp representation over the 8.5-h long experiment is discussed. Group speed fluctuations observed for a set of eigenrays with turning points at different depths in the water column are compared to the Brunt-Väisälä frequency.

  11. Gene-set based genome-wide association analysis for the speed of sound in two skeletal sites of Korean women

    PubMed Central

    Kwon, Ji-Sun; Kim, Sangsoo

    2014-01-01

    The speed of sound (SOS) value is an indicator of bone mineral density (BMD). Previous genome-wide association (GWA) studies have identified a number of genes, whose variations may affect BMD levels. However, their biological implications have been elusive. We re-analyzed the GWA study dataset for the SOS values in skeletal sites of 4,659 Korean women, using a gene-set analysis software, GSA-SNP. We identified 10 common representative GO terms, and 17 candidate genes between these two traits (PGS < 0.05). Implication of these GO terms and genes in the bone mechanism is well supported by the literature survey. Interestingly, the significance levels of some member genes were inversely related, in several gene-sets that were shared between two skeletal sites. This implies that biological process, rather than SNP or gene, is the substantial unit of genetic association for SOS in bone. In conclusion, our findings may provide new insights into the biological mechanisms for BMD. [BMB Reports 2014; 47(6): 348-353] PMID:24286325

  12. Speed of sound in diseased liver observed by scanning acoustic microscopy with 80 MHz and 250 MHz.

    PubMed

    Irie, So; Inoue, Kenta; Yoshida, Kenji; Mamou, Jonathan; Kobayashi, Kazuto; Maruyama, Hitoshi; Yamaguchi, Tadashi

    2016-01-01

    In this study, the speed of sound (SOS) of two types of rat livers (eight normal livers, four cirrhotic livers) was measured with a scanning acoustic microscope using two transducers, one of which had an 80-MHz and the other a 250-MHz center frequency. The 250-MHz transducer had a better spatial resolution adapted to studying fiber or hepatic parenchymal cells. In normal livers, averages of the SOS values were from 1598 to 1677 m/s at 80-MHz and from 1568 to 1668 m/s at 250-MHz. In the fiber tissue of cirrhotic livers, averages of the SOS values were from 1645 to 1658 m/s at 80-MHz and from 1610 to 1695 m/s at 250-MHz, while the SOS values in the other tissue of cirrhotic livers ranged from 1644 to 1709 m/s at 80-MHz and from 1641 to 1715 m/s at 250-MHz. In one liver, SOS in fiber tissue was larger than that of tissues without fiber while in others it was lower. The resulting two-dimensional SOS maps provide a unique quantitative insight of liver acoustic microstructures in a healthy liver and in a cirrhotic ones. This study would be helpful to understand the complex relationship between acoustic properties and liver disease including fiber tissue.

  13. Measurement properties of radial and tibial speed of sound for screening bone fragility in 10- to 12-year-old boys and girls.

    PubMed

    Rebocho, Lurdes M; Cardadeiro, Graça; Zymbal, Vera; Gonçalves, Ezequiel M; Sardinha, Luís B; Baptista, Fátima

    2014-01-01

    The objective of this study was to analyze measurement properties of the radial and tibial speed of sound (SoS) evaluated by quantitative ultrasound (QUS) for screening bone fragility. Bone fragility was defined as low whole body less head bone mineral density (WBLH BMD) measured by DXA (first tertile, 95% CI -1.1 to -0.9) and as past fractures evaluated by questionnaire. The sample included 319 nonobese boys and girls, ages 10-12 yr. All bone variables were standardized. The results revealed concordance coefficient correlations between WBLH BMD and radial and tibial SoS of 0.129 and 0.038, respectively. The regression lines between DXA and QUS variables were different from the identity lines. Cross-classification analysis by Kappa statistic showed that only 34% and 36% of the 113 participants categorized in the first tertile of WBLH BMD were also categorized in the first tertile of tibial and radial SoS, correspondingly. Logistic regression with gender and maturity adjustments demonstrates that radial SoS was the single significant variable in predicting OR for identifying participants with past fractures. In conclusion, the radial QUS revealed itself to be a valuable tool for screening bone fragility in youth of 10-12 yr, despite the absence of agreement with DXA WBLH BMD.

  14. The speed of sound and attenuation of an IEC agar-based tissue-mimicking material for high frequency ultrasound applications.

    PubMed

    Sun, Chao; Pye, Stephen D; Browne, Jacinta E; Janeczko, Anna; Ellis, Bill; Butler, Mairead B; Sboros, Vassilis; Thomson, Adrian J W; Brewin, Mark P; Earnshaw, Charles H; Moran, Carmel M

    2012-07-01

    This study characterized the acoustic properties of an International Electromechanical Commission (IEC) agar-based tissue mimicking material (TMM) at ultrasound frequencies in the range 10-47 MHz. A broadband reflection substitution technique was employed using two independent systems at 21°C ± 1°C. Using a commercially available preclinical ultrasound scanner and a scanning acoustic macroscope, the measured speeds of sound were 1547.4 ± 1.4 m∙s(-1) and 1548.0 ± 6.1 m∙s(-1), respectively, and were approximately constant over the frequency range. The measured attenuation (dB∙cm(-1)) was found to vary with frequency f (MHz) as 0.40f + 0.0076f(2). Using this polynomial equation and extrapolating to lower frequencies give values comparable to those published at lower frequencies and can estimate the attenuation of this TMM in the frequency range up to 47 MHz. This characterisation enhances understanding in the use of this TMM as a tissue equivalent material for high frequency ultrasound applications.

  15. Local modification of speed of sound in lithium alumino-silicate glass/ceramic material by pulsed laser irradiation and thermal processing.

    PubMed

    Kim, Y; Helvajian, H

    2013-11-21

    Glass and glass/ceramics are now used in modern devices with increasing frequency. A list of the notable material properties commonly will not include a capability to guide ultrasonic waves. The photosensitive glass ceramics (PSGCs), an old invention with recent technological rebirth, may enable this capability. The speed of sound (SoS) has been measured at an ultrasonic frequency (75 MHz) in a commercially available PSGC material. The measurements are made using a pulse echo time-of-flight (TOF) technique as a function of UV laser exposure and thermal processing. The measured increase in the SoS correlates with the density of crystalline matter present, which can be metered by controlling the exposure dose. For the Li2SiO3 crystalline phase, the results show the shear (transverse) wave mode velocity can be increased by 4.8% relative to an unexposed area where no crystalline matter exists. The maximum change in velocity for the longitudinal (compressional) wave mode is only 2%. However, by altering the thermal processing protocols to grow the high temperature Li2Si2O5 crystalline phase, the measured change in the SoS increases to 11% and 9%, respectively. These results permit the volumetric patterning of delay lines by laser direct write techniques for generating complex profile ultrasonic wave patterns. Moreover, by patterned 3D shaping (i.e., photostructuring), ultrasound energy can be harnessed and utilized to advantage.

  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. High-resolution Calculation of the Solar Global Convection with the Reduced Speed of Sound Technique. II. Near Surface Shear Layer with the Rotation

    NASA Astrophysics Data System (ADS)

    Hotta, H.; Rempel, M.; Yokoyama, T.

    2015-01-01

    We present a high-resolution, highly stratified numerical simulation of rotating thermal convection in a spherical shell. Our aim is to study in detail the processes that can maintain a near surface shear layer (NSSL) as inferred from helioseismology. Using the reduced speed of sound technique, we can extend our global convection simulation to 0.99 R ⊙ and include, near the top of our domain, small-scale convection with short timescales that is only weakly influenced by rotation. We find the formation of an NSSL preferentially in high latitudes in the depth range of r = 0.95-0.975 R ⊙. The maintenance mechanisms are summarized as follows. Convection under the weak influence of rotation leads to Reynolds stresses that transport angular momentum radially inward in all latitudes. This leads to the formation of a strong poleward-directed meridional flow and an NSSL, which is balanced in the meridional plane by forces resulting from the < v\\prime r v\\prime _θ > correlation of turbulent velocities. The origin of the required correlations depends to some degree on latitude. In high latitudes, a positive correlation < v\\prime _rv\\prime _θ > is induced in the NSSL by the poleward meridional flow whose amplitude increases with the radius, while a negative correlation is generated by the Coriolis force in bulk of the convection zone. In low latitudes, a positive correlation < v\\prime _rv\\prime _θ > results from rotationally aligned convection cells ("banana cells"). The force caused by these Reynolds stresses is in balance with the Coriolis force in the NSSL.

  18. Experimental observations of detonation in ammonium-nitrate-fuel-oil (ANFO) surrounded by a high-sound speed, shockless, aluminum confiner

    SciTech Connect

    Jackson, Scott I; Klyanda, Charles B; Short, Mark

    2010-01-01

    Detonations in explosive mixtures of ammonium-nitrate-fuel-oil (ANFO) confined by aluminum allow for transport of detonation energy ahead of the detonation front due to the aluminum sound speed exceeding the detonation velocity. The net effect of this energy transport on the detonation is unclear. It could enhance the detonation by precompressing the explosive near the wall. Alternatively, it could desensitize the explosive by crushing porosity required for shock initiation or destroying confinement ahead of the detonation. As these phenomena are not well understood, most numerical explosive models are unable to account for them. But with slowly detonating, non-ideal high explosive (NIHE) systems becoming increasing prevalent, proper understanding and prediction of the performance of these metal-confined NIHE systems is desirable. Experiments are discussed that measured the effect of this ANFO detonation energy transported upstream of the front by an aluminum confining tube. Detonation velocity, detonation front curvature, and aluminum response are recorded as a function of confiner wall thickness and length. Front curvature profiles display detonation acceleration near the confining surface, which is attributed to energy transported upstream modifying the flow. Average detonation velocities were seen to increase with increasing confiner thickness due to the additional inertial confinement of the reaction zone flow. Significant radial sidewall tube motion was observed immediately ahead of the detonation. Axial motion was also detected which interfered with the front curvature measurements in some cases. It was concluded that the confiner was able to transport energy ahead of the detonation and that this transport has a definite effect on the detonation.

  19. HIGH-RESOLUTION CALCULATION OF THE SOLAR GLOBAL CONVECTION WITH THE REDUCED SPEED OF SOUND TECHNIQUE. II. NEAR SURFACE SHEAR LAYER WITH THE ROTATION

    SciTech Connect

    Hotta, H.; Rempel, M.; Yokoyama, T.

    2015-01-01

    We present a high-resolution, highly stratified numerical simulation of rotating thermal convection in a spherical shell. Our aim is to study in detail the processes that can maintain a near surface shear layer (NSSL) as inferred from helioseismology. Using the reduced speed of sound technique, we can extend our global convection simulation to 0.99 R {sub ☉} and include, near the top of our domain, small-scale convection with short timescales that is only weakly influenced by rotation. We find the formation of an NSSL preferentially in high latitudes in the depth range of r = 0.95-0.975 R {sub ☉}. The maintenance mechanisms are summarized as follows. Convection under the weak influence of rotation leads to Reynolds stresses that transport angular momentum radially inward in all latitudes. This leads to the formation of a strong poleward-directed meridional flow and an NSSL, which is balanced in the meridional plane by forces resulting from the 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 correlation of turbulent velocities. The origin of the required correlations depends to some degree on latitude. In high latitudes, a positive correlation 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 is induced in the NSSL by the poleward meridional flow whose amplitude increases with the radius, while a negative correlation is generated by the Coriolis force in bulk of the convection zone. In low latitudes, a positive correlation 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 results from rotationally aligned convection cells ({sup b}anana cells{sup )}. The force caused by these Reynolds stresses is in balance with the Coriolis force in the NSSL.

  20. Reference characterisation of sound speed and attenuation of the IEC agar-based tissue-mimicking material up to a frequency of 60 MHz.

    PubMed

    Rajagopal, Srinath; Sadhoo, Neelaksh; Zeqiri, Bajram

    2015-01-01

    To support the development of clinical applications of high-frequency ultrasound, appropriate tissue-mimicking materials (TMMs) are required whose acoustic properties have been measured using validated techniques. This paper describes the characterisation of the sound speed (phase velocity) and attenuation coefficient of the International Electrotechnical Commission (IEC) agar-based TMM over the frequency range 1 to 60 MHz. Measurements implemented a broadband through-transmission substitution immersion technique over two overlapping frequency ranges, with co-axially aligned 50 MHz centre-frequency transducers employed for characterisation above 15 MHz. In keeping with usual practice employed within the technical literature, thin acoustic windows (membranes) made of 12-μm-thick Mylar protected the TMM from water damage. Various important sources of uncertainty that could compromise measurement accuracy have been identified and evaluated through a combination of experimental studies and modelling. These include TMM sample thickness, measured both manually and acoustically, and the influence of interfacial losses that, even for thin protective membranes, are significant at the frequencies of interest. In agreement with previous reports, the attenuation coefficient of the IEC TMM exhibited non-linear frequency dependence, particularly above 20 MHz, yielding a value of 0.93 ± 0.04 dB cm(-1) MHz(-1) at 60 MHz, derived at 21 ± 0.5°C. For the first time, phase velocity, measured with an estimated uncertainty of ±3.1 m s(-1), has been found to be dispersive over this extended frequency range, increasing from 1541 m s(-1) at 1 MHz to 1547 m s(-1) at 60 MHz. This work will help standardise acoustic property measurements, and establishes a reference measurement capability for TMMs underpinning clinical applications at elevated frequencies.

  1. Isentropic phase changes in dissociating gases and the method of sound dispersion for the investigation of homogeneous gas reactions with very high speed : Conclusion

    NASA Technical Reports Server (NTRS)

    Damkohler, Gerhard

    1950-01-01

    The analytical results of Part I are also applied to sound dispersion by friction and heat conduction, An irreversible change of momentum, energy, and type of particle corresponding to friction, heat conduction, and diffusion effects can appear both in the direction of the sound field and traverse to it. Longitudinal damping, the coupling of longitudinal damping and that due to chemical and physical changes, and coupling of diffusion and compositional changes are treated for a plane sound wave of infinite extent. The same principles are also applied to sound effects in cylindrical tubes. The limitations of the method are discussed in some detail.

  2. Using the Sound Card as a Timer

    NASA Astrophysics Data System (ADS)

    Aguiar, C. E.; Pereira, M. M.

    2011-01-01

    Experiments in mechanics often involve measuring time intervals much smaller than one second, a task that is hard to perform with handheld stopwatches. This is one of the reasons why photogate timers are so popular in school labs. There is an interesting alternative to stopwatches and photogates, easily available if one has access to a personal computer with sound-recording capability. The idea is simple: a computer sound card can record audio frequencies up to several kilohertz, which means it has a time resolution of a fraction of a millisecond, comparable to that of photogate timers. Many experiments in mechanics can be timed by the sound they produce, and in these situations a direct audio recording may provide accurate measurements of the time intervals of interest. This idea has already been explored in a few cases,1-5 and here we apply it to an experiment that our students found very enjoyable: measuring the speed of soccer balls they kicked.

  3. Sound propagation in the inhomogeneous ocean

    NASA Astrophysics Data System (ADS)

    Devany, Daniel L.

    1991-06-01

    By using a linear systems theory approach, an ocean medium transfer function based on the WKB approximation can be developed. The phase computations for the transfer function are made by evaluating the WKB phase integral. Two applications of ray acoustics theory are investigated as accurate, efficient alternatives to direct numerical integration of the WKB phase integral. Both applications base phase computations on signal travel time. The difference is their treatment of the sound-speed versus depth data pairs. One forms a sound-speed profile by using the piecewise linear approximation method while the other uses an Akima cubic spline fit to the data. Each method can identify source-to-receiver eigenrays and provide ray trace plots.

  4. Sound resonance in pipes with discrete Fourier transform

    NASA Astrophysics Data System (ADS)

    Aljalal, Abdulaziz M.

    2015-09-01

    Sound resonance in pipes is investigated using a readily available setup consisting of a pipe, loudspeaker, microphone, and laptop. Discrete Fourier transform is used to extract the amplitude and phase spectra from the recorded sound enabling determination of locations and shapes of resonance peaks accurately. Either white noise signal or sharp pulse signal is used as an excited input sound signal. Both have broad frequency spectra and the difference between them is explored. The shapes of the amplitude and phase spectra are found to be well fitted to the predicted shapes. The pipe is either closed at both ends, closed at only one end, or open at both ends. The speed of sound and the effective location of reflection at the open end are in excellent agreement with theory.

  5. Thermal Conductivity and Speed of Sound Measurements of Liquid Hydrazine (N2H4) at 293.15K and 0.101 MPa to 2.068 MPa

    DTIC Science & Technology

    2008-04-25

    8-98) Prescribed by ANSI Std. 239.18 Nomenclature X = thermal conductivity, Wm -1OC -I NA = Avogadro constant , 6.02214 x 10 - 23 mol- V = molar...volume, m3 mol-I k = Boltzmann constant , 1.38066 x 10 - 23 j K - CN = Speed of sound, m s -I MMH = monomethyl hydrazine UDMH = unsymmetric dimethyl...hydrazine T = temperature, K 1, = constant current, A Vf = voltage, V Af = liquid resonance frequency difference, Hz L = pathlength, m R = resistance, Q A,B

  6. High-Frequency CTD Measurements for Accurate GPS/acoustic Sea-floor Crustal Deformation Measurement System

    NASA Astrophysics Data System (ADS)

    Tadokoro, K.; Yasuda, K.; Taniguchi, S.; Uemura, Y.; Matsuhiro, K.

    2015-12-01

    The GPS/acoustic sea-floor crustal deformation measurement system has developed as a useful tool to observe tectonic deformation especially at subduction zones. One of the factors preventing accurate GPS/acoustic sea-floor crustal deformation measurement is horizontal heterogeneity of sound speed in the ocean. It is therefore necessary to measure the gradient directly from sound speed structure. We report results of high-frequency CTD measurements using Underway CTD (UCTD) in the Kuroshio region. We perform the UCTD measurements on May 2nd, 2015 at two stations (TCA and TOA) above the sea-floor benchmarks installed across the Nankai Trough, off the south-east of Kii Peninsula, middle Japan. The number of measurement points is six at each station along circles with a diameter of 1.8 nautical miles around the sea-floor benchmark. The stations TCA and TOA are located on the edge and the interior of the Kuroshio current, respectively, judging from difference in sea water density measured at the two stations, as well as a satellite image of sea-surface temperature distribution. We detect a sound speed gradient of high speeds in the southern part and low speeds in the northern part at the two stations. At the TCA station, the gradient is noticeable down to 300 m in depth; the maximum difference in sound speed is +/- 5 m/s. The sound speed difference is as small as +/- 1.3 m/s at depths below 300 m, which causes seafloor benchmark positioning error as large as 1 m. At the TOA station, the gradient is extremely small down to 100 m in depth. The maximum difference in sound speed is less than +/- 0.3 m/s that is negligible small for seafloor benchmark positioning error. Clear gradient of high speed is observed to the depths; the maximum difference in sound speed is +/- 0.8-0.9 m/s, causing seafloor benchmark positioning error of several tens centimeters. The UCTD measurement is effective tool to detect sound speed gradient. We establish a method for accurate sea

  7. 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

  8. 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…

  9. 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].

  10. 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

  11. 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.

  12. 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 ...

  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. Development of a practical ultrasonic approach for simultaneous measurement of the thickness and the sound speed in human skull bones: a laboratory phantom study.

    PubMed

    Wydra, A; Malyarenko, E; Shapoori, K; Maev, R Gr

    2013-02-21

    The availability of a non-invasive express method for the in vivo measurement of both sound velocity and thickness of the human skull bone would be of great benefit to various transcranial ultrasonic imaging and treatment applications. This paper investigates two ultrasonic methods that measure both parameters and are based on the variable focus technique. All the experiments described in this paper were conducted on specially prepared custom skull bone phantoms, including flat and deformed samples, designed and developed in our laboratory. The first method uses a single immersion 2.25 MHz ultrasonic transducer consecutively focused on the front and back surfaces of the sample. The accuracy and precision of this method are demonstrated via single point measurements on flat samples with and without porosity. The measurement results from a specimen with the randomly curved back surface show the possibility of obtaining the inner profile of the skull bone. The second presented method is a practical modification of the variable focus technique for the linear phased array case. The method was tested on flat and curved skull bone phantoms with and without inner porosity showing higher measurement accuracy and simpler practical realization than its scanning counterpart.

  15. 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.

  16. The compressibility of K2CO3-Na2CO3-Li2CO3-CaCO3 liquids derived from sound speed measurements: implications for the fusion curve of CaCO3

    NASA Astrophysics Data System (ADS)

    O'Leary, M. C.; Lange, R. A.; Ai, Y.

    2009-12-01

    Carbonate in the mantle is an important reservoir of carbon, which is released to the atmosphere as CO2 through volcanism. Therefore, it is of considerable interest to extend thermodynamic models of partial melting in the mantle at elevated pressures to carbonate-bearing lithologies. In order to achieve this, thermodynamic data on carbonate liquids are needed, including their density, thermal expansion and compressibility. In order to obtain information on the CaCO3 and MgCO3 liquid components, which are the most important carbonate components in the mantle, we’ve employed a strategy where the alkaline earth carbonates are mixed with the alkali carbonates in order to lower the liquidus temperatures of various sample liquids to values below the decomposition of carbonate liquids at one bar (~1300 K). This permits thermodynamic property measurements of the multi-component liquids to be made at one bar. If it can be shown that the volumetric properties of carbonate liquids mix ideally with respect to composition, then the partial molar volumetric properties of the CaCO3 and MgCO3 liquid components can be derived. In a previous study (Liu et al., 2003), the volume and thermal expansion of mixed K2CO3-Na2CO3-Li2CO3-CaCO3 liquids were reported and shown to behave ideally with respect to composition. In this study, sound speed measurements on mixed K2CO3-Na2CO3-Li2CO3-CaCO3 liquids at one bar, under a CO2 atmosphere from 725 to 1242 K (over 500 degrees) will be reported. Measurements are made with a frequency-sweep acoustic interferometer, where the liquids are held in Pt crucible, and the upper buffer rod is made of alumina. Our sound speed measurements on the pure end-member alkali carbonate liquids (e.g., Na2CO3-) are in excellent agreement with previous sound speed measurements on carbonate liquids reported in the literature (Zhu et al., 1991). The two data sets match within 0.4%, on average, which is within experimental error. The goal of this study is to test

  17. Density and sound speed measurements on model basalt (An-Di-Hd) liquids at one bar: New constraints on the partial molar volume and compressibility of the FeO component

    NASA Astrophysics Data System (ADS)

    Guo, Xuan; Lange, Rebecca A.; Ai, Yuhui

    2014-02-01

    Density and sound speed measurements were obtained over a wide range of temperature for three model basalt liquids in the An-Di-Hd (CaAl2Si2O8-CaMgSi2O6-CaFeSi2O6) system. High-temperature (1585-1838 K) double-bob density measurements were combined with low-temperature (943-930 K) measurements at the limiting fictive temperature for each sample to provide liquid volume data over a temperature interval of ∼900 K. In addition, relaxed sound speeds were obtained with a frequency sweep acoustic interferometer from 1665-1876 K. An ideal mixing model for molar volume, thermal expansivity, and isothermal compressibility recovers the new data from this study and leads to the following fitted values (±2σ) at 1723 K for VbarFeO (12.86±0.32 cm/mol), ∂VbarFeO/∂T((3.69±1.16)×10-3 cm/mol-K) and βbarT,FeO((4.72±0.46)×10-2 GPa). These volumetric properties for the FeO component are estimated to reflect Fe2+ in an average coordination of 5.7 (±0.2), based on the relationship between VbarFeO and Fe2+ coordination derived by a comparison to mineral molar volumes (Guo et al., 2013). Application of these volumetric data to a calculation of the pressure dependence of the Fe-Mg exchange reaction between orthopyroxene and basaltic liquid results in a small decrease in Fe-MgKD with pressure. In contrast, partial melting experiments of peridotite show a small increase in Fe-MgKD(opx-liq) with pressure (e.g., Walter, 1998). This difference in the pressure dependence is proposed to reflect the role of alkalis in reducing the average coordination number of Fe2+ toward five compared to the alkali-free model basalt compositions in this study, thus changing the volume and compressibility of the FeO liquid component. The results from this study may be most appropriately applied to lunar basalts, which are impoverished in alkalis.

  18. Improved methods for fan sound field determination

    NASA Technical Reports Server (NTRS)

    Cicon, D. E.; Sofrin, T. G.; Mathews, D. C.

    1981-01-01

    Several methods for determining acoustic mode structure in aircraft turbofan engines using wall microphone data were studied. A method for reducing data was devised and implemented which makes the definition of discrete coherent sound fields measured in the presence of engine speed fluctuation more accurate. For the analytical methods, algorithms were developed to define the dominant circumferential modes from full and partial circumferential arrays of microphones. Axial arrays were explored to define mode structure as a function of cutoff ratio, and the use of data taken at several constant speeds was also evaluated in an attempt to reduce instrumentation requirements. Sensitivities of the various methods to microphone density, array size and measurement error were evaluated and results of these studies showed these new methods to be impractical. The data reduction method used to reduce the effects of engine speed variation consisted of an electronic circuit which windowed the data so that signal enhancement could occur only when the speed was within a narrow range.

  19. Fast recognition of musical sounds based on timbre.

    PubMed

    Agus, Trevor R; Suied, Clara; Thorpe, Simon J; Pressnitzer, Daniel

    2012-05-01

    Human listeners seem to have an impressive ability to recognize a wide variety of natural sounds. However, there is surprisingly little quantitative evidence to characterize this fundamental ability. Here the speed and accuracy of musical-sound recognition were measured psychophysically with a rich but acoustically balanced stimulus set. The set comprised recordings of notes from musical instruments and sung vowels. In a first experiment, reaction times were collected for three target categories: voice, percussion, and strings. In a go/no-go task, listeners reacted as quickly as possible to members of a target category while withholding responses to distractors (a diverse set of musical instruments). Results showed near-perfect accuracy and fast reaction times, particularly for voices. In a second experiment, voices were recognized among strings and vice-versa. Again, reaction times to voices were faster. In a third experiment, auditory chimeras were created to retain only spectral or temporal features of the voice. Chimeras were recognized accurately, but not as quickly as natural voices. Altogether, the data suggest rapid and accurate neural mechanisms for musical-sound recognition based on selectivity to complex spectro-temporal signatures of sound sources.

  20. 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.

  1. 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 ...

  2. 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)

  3. Quantifying Hurricane Wind Speed with Undersea Sound

    DTIC Science & Technology

    2006-06-01

    138]. These second order non-linear or perturbation-based theories should not be con- fused with the linear theories proposed by Banerji [5] and Bowen...October 2001. Technical report, National Hurricane Center, 2001. [5] S. K. Banerji . Microseisms associated with disturbed weather in the indian seas...Phil. Trans. Roy. Soc. Lon. Ser. A., 229:287-328, 1930. [6] S. K. Banerji . Theory of microseisms. Proc. Indian Acad. Sci., 1:727-753, 1935. [7] R. L

  4. Sound Speed and Attenuation in Multiphase Media

    DTIC Science & Technology

    2009-01-01

    characteristics of muddy sediments." POMA 5 070002 (2009) [15] A. D. Pierce and W. M. Carey, "Card-house theory of mud sediments containing kaolinite and...W. M. Carey, "Card-house theory of mud sediments containing kaolinite and its acoustical implications," POMA 5, (2008). 5 6 [8] W. M. Carey and

  5. 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.

  6. Speed of sound and acoustic attenuation of compounds affected during optoacoustic monitoring of thermal therapies measured in the temperature range from 5°C to 60°C

    NASA Astrophysics Data System (ADS)

    Oruganti, Tanmayi; Petrova, Elena; Oraevsky, Alexander A.; Ermilov, Sergey A.

    2015-03-01

    Optoacoustic (photoacoustic) imaging is being adopted for monitoring tissue temperature during hypothermic and hyperthermic cancer treatments. The technique's accuracy benefits from the knowledge of speed of sound (SoS) and acoustic coefficient of attenuation (AcA) as they change with temperature in biological tissues, blood, and acoustic lens of an ultrasound probe. In these studies we measured SoS and AcA of different ex vivo tissues and blood components (plasma and erythrocyte concentrates) in the temperature range from 5°C to 60°C. We used the technique based on measurements of time-delay and spectral amplitude of pressure pulses generated by wideband planar acoustic waves propagating through the interrogated medium. Water was used as a reference medium with known acoustic properties. In order to validate our experimental technique, we measured the temperature dependence of SoS and AcA for aqueous NaCl solution of known concentration and obtained the results in agreement with published data. Similar to NaCl solution and pure water, SoS in blood and plasma was monotonously increasing with temperature. However, SoS of erythrocyte concentrates displayed abnormalities at temperatures above 45°C, suggesting potential effects from hemoglobin denaturation and/or hemolysis of erythrocytes. On the contrary to aqueous solutions, the SoS in polyvinyl-chloride (plastisol) - a material frequently used for mimicking optical and acoustic properties of tissues - decreased with temperature. We also measured SoS and AcA in silicon material of an acoustic lens and did not observe temperature-related changes of SoS.

  7. Tactile/kinesthetic stimulation (TKS) increases tibial speed of sound and urinary osteocalcin (U-MidOC and unOC) in premature infants (29-32 wks PMA)

    PubMed Central

    Haley, S; Beachy, J; Ivaska, KK; Slater, H; Smith, S; Moyer-Mileur, LJ

    2012-01-01

    Preterm delivery (<37 wks post-menstrual age) is associated with suboptimal bone mass. We hypothesized that tactile/kinesthetic stimulation (TKS), a form of infant massage that incorporates kinesthetic movement, would increase bone strength and markers of bone accretion in preterm infants. Preterm, AGA infants (29-32 wks) were randomly assigned to TKS (N=20) or Control (N=20). Twice daily TKS was provided six days per week for two weeks. Control infants received the same care without TKS treatment. Treatment was masked to parents, health care providers, and study personnel. Baseline and week two measures were collected for tibial speed of sound (tSOS, m/sec), a surrogate for bone strength, by quantitative ultrasound (Sunlight8000) and urine markers of bone metabolism, pyridinium crosslinks and osteocalcin (U-MidOC and unOC). Infant characteristics at birth and study entry as well as energy/nutrient intake were similar between TKS and Control. TKS intervention attenuated the decrease in tSOS observed in Control infants (p<0.05). Urinary pyridinium crosslinks decreased over time in both TKS and CTL (p<0.005). TKS infants experienced greater increases in urinary osteocalcin (U-MidOC, p<0.001 and unOC, p<0.05). We conclude that TKS improves bone strength in premature infants by attenuating the decrease that normally follows preterm birth. Further, biomarkers of bone metabolism suggest a modification in bone turnover in TKS infants in favor of bone accretion. Taken together, we speculate that TKS improves bone mineralization. PMID:22846674

  8. High-resolution calculations of the solar global convection with the reduced speed of sound technique. I. The structure of the convection and the magnetic field without the rotation

    SciTech Connect

    Hotta, H.; Yokoyama, T.; Rempel, M.

    2014-05-01

    We carry out non-rotating high-resolution calculations of the solar global convection, which resolve convective scales of less than 10 Mm. To cope with the low Mach number conditions in the lower convection zone, we use the reduced speed of sound technique (RSST), which is simple to implement and requires only local communication in the parallel computation. In addition, the RSST allows us to expand the computational domain upward to about 0.99 R {sub ☉}, as it can also handle compressible flows. Using this approach, we study the solar convection zone on the global scale, including small-scale near-surface convection. In particular, we investigate the influence of the top boundary condition on the convective structure throughout the convection zone as well as on small-scale dynamo action. Our main conclusions are as follows. (1) The small-scale downflows generated in the near-surface layer penetrate into deeper layers to some extent and excite small-scale turbulence in the region >0.9 R {sub ☉}, where R {sub ☉} is the solar radius. (2) In the deeper convection zone (<0.9 R {sub ☉}), the convection is not influenced by the location of the upper boundary. (3) Using a large eddy simulation approach, we can achieve small-scale dynamo action and maintain a field of about 0.15B {sub eq}-0.25B {sub eq} throughout the convection zone, where B {sub eq} is the equipartition magnetic field to the kinetic energy. (4) The overall dynamo efficiency varies significantly in the convection zone as a consequence of the downward directed Poynting flux and the depth variation of the intrinsic convective scales.

  9. 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.

  10. 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

  11. 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.

  12. 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

  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. 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

  15. 49 CFR 230.68 - Speed indicators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Speed indicators. 230.68 Section 230.68... Tenders Speed Indicators § 230.68 Speed indicators. Steam locomotives that operate at speeds in excess of... indicators. Where equipped, speed indicators shall be maintained to ensure accurate functioning. Ash Pans...

  16. 49 CFR 230.68 - Speed indicators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Speed indicators. 230.68 Section 230.68... Tenders Speed Indicators § 230.68 Speed indicators. Steam locomotives that operate at speeds in excess of... indicators. Where equipped, speed indicators shall be maintained to ensure accurate functioning. Ash Pans...

  17. Tuning, Validation, and Uncertainty Estimates for a Sound Exposure Model

    DTIC Science & Technology

    2011-09-01

    3 1. Bathymetry and Sea Surface...............................................................3 2. Sound Speed Profiles...EXECUTION A. ENVIRONMENTAL MODEL 1. Bathymetry and Sea Surface Bathymetry data was added to the NSPE model from the 3 arc-second U.S. Coastal...Other model inputs included bathymetry from the U.S. Coastal Relief Model, and sound speed profiles from Expendable Bathythermographs (XBT) and

  18. Anomalous Cherenkov spin-orbit sound

    SciTech Connect

    Smirnov, Sergey

    2011-02-15

    The Cherenkov effect is a well-known phenomenon in the electrodynamics of fast charged particles passing through transparent media. If the particle is faster than the light in a given medium, the medium emits a forward light cone. This beautiful phenomenon has an acoustic counterpart where the role of photons is played by phonons and the role of the speed of light is played by the sound velocity. In this case the medium emits a forward sound cone. Here, we show that in a system with spin-orbit interactions in addition to this normal Cherenkov sound there appears an anomalous Cherenkov sound with forward and backward sound propagation. Furthermore, we demonstrate that the transition from the normal to anomalous Cherenkov sound happens in a singular way at the Cherenkov cone angle. The detection of this acoustic singularity therefore represents an alternative experimental tool for the measurement of the spin-orbit coupling strength.

  19. 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

  20. 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

  1. 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.

  2. Wind speed measurement by paper anemometer

    NASA Astrophysics Data System (ADS)

    Zhong, Juhua; Cheng, Zhongqi; Guan, Wenchuan

    2011-09-01

    A simple wind speed measurement device, a paper anemometer, is fabricated based on the theory of standing waves. In providing the working profile of the paper anemometer, an experimental device is established, which consists of an anemometer sensor, a sound sensor, a microphone, paper strips, a paper cup, and sonic acquisition software. It shows that the sound wave detected in the paper cup has a larger amplitude and the noise is depressed, though the frequency of the sound is twice that detected directly from the strip. From the experiments, we find that the frequency of the sonic wave does not change with wind speed; however, its amplitude increases with wind speed. To predict the wind speed, a correlation is established from the sound wave amplitude.

  3. 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.

  4. SoundCompass: A Distributed MEMS Microphone Array-Based Sensor for Sound Source Localization

    PubMed Central

    Tiete, Jelmer; Domínguez, Federico; da Silva, Bruno; Segers, Laurent; Steenhaut, Kris; Touhafi, Abdellah

    2014-01-01

    Sound source localization is a well-researched subject with applications ranging from localizing sniper fire in urban battlefields to cataloging wildlife in rural areas. One critical application is the localization of noise pollution sources in urban environments, due to an increasing body of evidence linking noise pollution to adverse effects on human health. Current noise mapping techniques often fail to accurately identify noise pollution sources, because they rely on the interpolation of a limited number of scattered sound sensors. Aiming to produce accurate noise pollution maps, we developed the SoundCompass, a low-cost sound sensor capable of measuring local noise levels and sound field directionality. Our first prototype is composed of a sensor array of 52 Microelectromechanical systems (MEMS) microphones, an inertial measuring unit and a low-power field-programmable gate array (FPGA). This article presents the SoundCompass’s hardware and firmware design together with a data fusion technique that exploits the sensing capabilities of the SoundCompass in a wireless sensor network to localize noise pollution sources. Live tests produced a sound source localization accuracy of a few centimeters in a 25-m2 anechoic chamber, while simulation results accurately located up to five broadband sound sources in a 10,000-m2 open field. PMID:24463431

  5. SoundCompass: a distributed MEMS microphone array-based sensor for sound source localization.

    PubMed

    Tiete, Jelmer; Domínguez, Federico; da Silva, Bruno; Segers, Laurent; Steenhaut, Kris; Touhafi, Abdellah

    2014-01-23

    Sound source localization is a well-researched subject with applications ranging from localizing sniper fire in urban battlefields to cataloging wildlife in rural areas. One critical application is the localization of noise pollution sources in urban environments, due to an increasing body of evidence linking noise pollution to adverse effects on human health. Current noise mapping techniques often fail to accurately identify noise pollution sources, because they rely on the interpolation of a limited number of scattered sound sensors. Aiming to produce accurate noise pollution maps, we developed the SoundCompass, a low-cost sound sensor capable of measuring local noise levels and sound field directionality. Our first prototype is composed of a sensor array of 52 Microelectromechanical systems (MEMS) microphones, an inertial measuring unit and a low-power field-programmable gate array (FPGA). This article presents the SoundCompass's hardware and firmware design together with a data fusion technique that exploits the sensing capabilities of the SoundCompass in a wireless sensor network to localize noise pollution sources. Live tests produced a sound source localization accuracy of a few centimeters in a 25-m2 anechoic chamber, while simulation results accurately located up to five broadband sound sources in a 10,000-m2 open field.

  6. 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.

  7. 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.

  8. 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.

  9. Breaking the sound barrier in holography

    NASA Astrophysics Data System (ADS)

    Hoyos, Carlos; Jokela, Niko; Rodríguez Fernández, David; Vuorinen, Aleksi

    2016-11-01

    It has been conjectured that the speed of sound in holographic models with UV fixed points has an upper bound set by the value of the quantity in conformal field theory. If true, this would set stringent constraints for the presence of strongly coupled quark matter in the cores of physical neutron stars, as the existence of two-solar-mass stars appears to demand a very stiff equation of state. In this article, we present a family of counterexamples to the speed of sound conjecture, consisting of strongly coupled theories at finite density. The theories we consider include N =4 super Yang-Mills at finite R -charge density and nonzero gaugino masses, while the holographic duals are Einstein-Maxwell theories with a minimally coupled scalar in a charged black hole geometry. We show that for a small breaking of conformal invariance, the speed of sound approaches the conformal value from above at large chemical potentials.

  10. Sounds of a Star

    NASA Astrophysics Data System (ADS)

    2001-06-01

    colours show element displacements in opposite directions. Geologists monitor how seismic waves generated by earthquakes propagate through the Earth, and thus learn about the inner structure of our planet. The same technique works for stars. The Sun, our nearest star and a typical middle-age member of its class, has been investigated in this way since the 1960's. With "solar seismology" , astronomers have been able to learn much about the inner parts of the star, and not only the outer layers normally visible to the telescopes. In the Sun, heat is bubbling up from the central regions where enormous amount of energy is created by nuclear reactions . In the so-called convective zone , the gas is virtually boiling, and hot gas-bubbles are rising with a speed that is close to that of sound. Much like you can hear when water starts to boil, the turbulent convection in the Sun creates noise . These sound waves then propagate through the solar interior and are reflected on the surface, making it oscillate. This "ringing" is well observed in the Sun, where the amplitude and frequency of the oscillations provide astronomers with plenty of information about the physical conditions in the solar interior. From the Sun to the stars There is every reason to believe that our Sun is a quite normal star of its type. Other stars that are similar to the Sun are therefore likely to pulsate in much the same way as the Sun. The search for such oscillations in other solar-like stars has, however, been a long and difficult one. The problem is simply that the pulsations are tiny, so very great precision is needed in the measurements. However, the last few years have seen considerable progress in asteroseismology, and François Bouchy and Fabien Carrier from the Geneva Observatory have now been able to detect unambiguous acoustic oscillations in the Solar-twin star, Alpha Centauri A. The bright and nearby star Alpha Centauri Alpha Centauri (Alpha Cen) [1] is the brightest star in the constellation

  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. 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.

  13. 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…

  14. 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…

  15. 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…

  16. Modeling Aerodynamically Generated Sound of Helicopter Rotors

    NASA Technical Reports Server (NTRS)

    Brentner, Kenneth S.; Farassat, F.

    2002-01-01

    A great deal of progress has been made in the modeling of aerodynamically generated sound of rotors over the past decade. Although the modeling effort has focused on helicopter main rotors, the theory is generally valid for a wide range of rotor configurations. The Ffowcs Williams Hawkings (FW-H) equation has been the foundation for much of the development. The monopole and dipole source terms of the FW-H equation account for the thickness and loading noise, respectively. Bladevortex-interaction noise and broadband noise are important types of loading noise, hence much research has been directed toward the accurate modeling of these noise mechanisms. Both subsonic and supersonic quadrupole noise formulations have been developed for the prediction of high-speed impulsive noise. In an effort to eliminate the need to compute the quadrupole contribution, the FW-H equation has also been utilized on permeable surfaces surrounding all physical noise sources. Comparisons of the Kirchhoff formulation for moving surfaces with the FW-H equation have shown that the Kirchhoff formulation for moving surfaces can give erroneous results for aeroacoustic problems. Finally, significant progress has been made incorporating the rotor noise models into full vehicle noise prediction tools.

  17. 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.

  18. The mechanical forces in katydid sound production

    NASA Astrophysics Data System (ADS)

    Xiao, Huaping; Chiu, Cheng-Wei; Zhou, Yan; He, Xingliang; Epstein, Ben; Liang, Hong

    2013-10-01

    Katydids and crickets generate their characteristic calling sound by rubbing their wings together. The mechanisms of the rubbing force, however, have not been extensively studied. The change of mechanical force with external parameters (speed and applied load) in the stridulation process has not been reported. Our current study aims to investigate the mechanical forces of katydid stridulation. Four pairs of files and plectrums from a katydid, which are responsible for the katydid's sound production, were examined with a specially designed experimental configuration. Due to the asymmetric nature of the wing motion in their opening and closing, the contact between the plectrum and file resembles that of a ratchet. Multiple frequencies were generated during experimental wing rubbing so that a calling-like sound was produced. Results showed that the morphology of the plectrum/file contact has significant effects on mechanical forces induced on the wings and resulting sound production. The roles of the mechanical forces include sound generation, tone modification, and energy consumption. The findings in this work reveal the variation trend of mechanical force with sliding speed and applied load. The frequency and amplitude of the sound wave produced in tribo-test are close to those in natural condition. By mimicking the microstructure of the plectrum and file teeth, acoustic instruments with high mechanical energy conversion rate can be developed. Our results provide new approaches in the design and improvement of micro-machines for acoustic applications, as well as in hybrid robotic systems.

  19. Subtyping Children with Speech Sound Disorders by Endophenotypes

    ERIC Educational Resources Information Center

    Lewis, Barbara A.; Avrich, Allison A.; Freebairn, Lisa A.; Taylor, H. Gerry; Iyengar, Sudha K.; Stein, Catherine M.

    2011-01-01

    Purpose: The present study examined associations of 5 endophenotypes (i.e., measurable skills that are closely associated with speech sound disorders and are useful in detecting genetic influences on speech sound production), oral motor skills, phonological memory, phonological awareness, vocabulary, and speeded naming, with 3 clinical criteria…

  20. Aerodynamics of Sounding-Rocket Geometries

    NASA Technical Reports Server (NTRS)

    Barrowman, J.

    1982-01-01

    Theoretical aerodynamics program TAD predicts aerodynamic characteristics of vehicles with sounding-rocket configurations. These slender, Axisymmetric finned vehicles have a wide range of aeronautical applications from rockets to high-speed armament. TAD calculates characteristics of separate portions of vehicle, calculates interference between portions, and combines results to form total vehicle solution.

  1. 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.

  2. 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 ...

  3. Use of natural sounds and metaphors for data perceptualization

    NASA Astrophysics Data System (ADS)

    Lodha, Suresh K.; Venable, Ellen; Marsh, David; Meads, Doanna; Manh, Nguyet; Robinson, Casey; Roskin, Krishna

    2001-05-01

    We describe three systems that use natural or event-based sounds as means of data delivery. In these systems we have mapped data to natural sounds using metaphors. In the first system we evaluate the use of sounds of air, horn, and train to convey ordered numeric values between 1 to 6. An example of the metaphor used here is the association of speed values to the sound of a moving train at different speeds. In the second system, we use sounds of ocean waves to convey whether the exposure in a protein structural alignment is buried, partially exposed or fully exposed. The metaphor used here is the association of sound with how exposed the user is with respect to the ocean. In the third system, we map animal sounds such as the sound of a roaring lion or a chirping bird to certain stocks based on user preferences. The behavior of the stocks are then sounded by the use of whistles and car crash to signify the movement in process of the stocks. An up whistling sound can be clearly associated with an uptrend. We present and discuss the results of user evaluation studies for all the three systems.

  4. Decadal trends in Indian Ocean ambient sound.

    PubMed

    Miksis-Olds, Jennifer L; Bradley, David L; Niu, Xiaoyue Maggie

    2013-11-01

    The increase of ocean noise documented in the North Pacific has sparked concern on whether the observed increases are a global or regional phenomenon. This work provides evidence of low frequency sound increases in the Indian Ocean. A decade (2002-2012) of recordings made off the island of Diego Garcia, UK in the Indian Ocean was parsed into time series according to frequency band and sound level. Quarterly sound level comparisons between the first and last years were also performed. The combination of time series and temporal comparison analyses over multiple measurement parameters produced results beyond those obtainable from a single parameter analysis. The ocean sound floor has increased over the past decade in the Indian Ocean. Increases were most prominent in recordings made south of Diego Garcia in the 85-105 Hz band. The highest sound level trends differed between the two sides of the island; the highest sound levels decreased in the north and increased in the south. Rate, direction, and magnitude of changes among the multiple parameters supported interpretation of source functions driving the trends. The observed sound floor increases are consistent with concurrent increases in shipping, wind speed, wave height, and blue whale abundance in the Indian Ocean.

  5. Category 5: Sound Generation in Viscous Problems

    NASA Technical Reports Server (NTRS)

    Lee, Soogab; Henderson, Brenda

    2004-01-01

    Two problems are considered. Problem 1: Aeolian tones, sound generation by flow over cylinders, are relevant to airframe and power plant noise (heat exchanger, power transmission lines and chimneys). The purpose of this problem is to test the ability of a CFD/CAA code to accurately predict sound generation by viscous flows and sound propagation through interactions between acoustic wave & solid wall and between acoustic waves & shear layers. Problem 2: Sound generation by flow over a cavity.Air flows over the cavity shown below with a mean approach flow velocity of 50 m/s. The boundary layer that develops over the flat plate is turbulent with a thickness of 14 mm at the entrance to the cavity. Calculate the power spectra at the center of each cavit wall and the center of the cavity floor. Experimental data will be available for comparison.

  6. Heart sounds: are you listening? Part 1.

    PubMed

    Reimer-Kent, Jocelyn

    2013-01-01

    All nurses should have an understanding of heart sounds and be proficient in cardiac auscultation. Unfortunately, this skill is not part of many nursing school curricula, nor is it necessarily a required skillfor employment. Yet, being able to listen and accurately describe heart sounds has tangible benefits to the patient, as it is an integral part of a complete cardiac assessment. In this two-part article, I will review the fundamentals of cardiac auscultation, how cardiac anatomy and physiology relate to heart sounds, and describe the various heart sounds. Whether you are a beginner or a seasoned nurse, it is never too early or too late to add this important diagnostic skill to your assessment tool kit.

  7. 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.

  8. Effects of Sound on the Marine Environment

    DTIC Science & Technology

    2012-09-30

    includes acoustic sources, propagation and the interaction of sound with animal behavior models. Determining the necessary environmental information...between human intuition and detailed propagation models. The development of a model combining simple predictions of transmission loss could provide a... human intuition and more rigorous computer models; making marine mammal exposure calculations faster and more accurate. Since these models are

  9. Effects of Sound on the Marine Environment

    DTIC Science & Technology

    2011-09-30

    includes acoustic sources, propagation and the interaction of sound with animal behavior models. Determining the necessary environmental information...to bridge the gap between human intuition and detailed propagation models. The development of a model combining simple predictions of transmission...model would fill a gap between human intuition and more rigorous computer models; making marine mammal exposure calculations faster and more accurate

  10. 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

  11. More sound of church bells: Authors' correction

    NASA Astrophysics Data System (ADS)

    Vogt, Patrik; Kasper, Lutz; Burde, Jan-Philipp

    2016-01-01

    In the recently published article "The Sound of Church Bells: Tracking Down the Secret of a Traditional Arts and Crafts Trade," the bell frequencies have been erroneously oversimplified. The problem affects Eqs. (2) and (3), which were derived from the elementary "coffee mug model" and in which we used the speed of sound in air. However, this does not make sense from a physical point of view, since air only acts as a sound carrier, not as a sound source in the case of bells. Due to the excellent fit of the theoretical model with the empirical data, we unfortunately failed to notice this error before publication. However, all other equations, e.g., the introduction of the correction factor in Eq. (4) and the estimation of the mass in Eqs. (5) and (6) are not affected by this error, since they represent empirical models. However, it is unfortunate to introduce the speed of sound in air as a constant in Eqs. (4) and (6). Instead, we suggest the following simple rule of thumb for relating the radius of a church bell R to its humming frequency fhum:

  12. Accurate Finite Difference Algorithms

    NASA Technical Reports Server (NTRS)

    Goodrich, John W.

    1996-01-01

    Two families of finite difference algorithms for computational aeroacoustics are presented and compared. All of the algorithms are single step explicit methods, they have the same order of accuracy in both space and time, with examples up to eleventh order, and they have multidimensional extensions. One of the algorithm families has spectral like high resolution. Propagation with high order and high resolution algorithms can produce accurate results after O(10(exp 6)) periods of propagation with eight grid points per wavelength.

  13. Accurate monotone cubic interpolation

    NASA Technical Reports Server (NTRS)

    Huynh, Hung T.

    1991-01-01

    Monotone piecewise cubic interpolants are simple and effective. They are generally third-order accurate, except near strict local extrema where accuracy degenerates to second-order due to the monotonicity constraint. Algorithms for piecewise cubic interpolants, which preserve monotonicity as well as uniform third and fourth-order accuracy are presented. The gain of accuracy is obtained by relaxing the monotonicity constraint in a geometric framework in which the median function plays a crucial role.

  14. Detection of patients considering observation frequency of continuous and discontinuous adventitious sounds in lung sounds.

    PubMed

    Nakamura, Naoki; Yamashita, Masaru; Matsunaga, Shoichi

    2016-08-01

    We propose an improved approach for distinguishing between healthy subjects and patients with pulmonary emphysema by the use of one stochastic acoustic model for continuous adventitious sounds and another for discontinuous adventitious sounds. These models are able to represent the spectral features of the adventitious sounds for the detection of abnormal respiration. However, abnormal respiratory sounds with unclassifiable spectral features are present among the continuous and discontinuous adventitious sounds and mixing noises. These sounds cause difficulties in achieving a highly accurate classification. In this study, the difference in occurrence frequencies between two types of adventitious sounds for each considered auscultation point and inspiration/expiration was considered. This difference, in combination with the confusion tendency of the classifier, was formulated as the validity score of each respiratory sound. The conventional spectral likelihood and the newly formulated validity score were combined to perform detection of abnormal respiration and patients. In the classification of healthy subjects and patients, the proposed approach achieved a higher classification rate (87.7%) than the conventional method (85.2%), demonstrating the statistical superiority (5% level) of the former.

  15. 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.

  16. 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

  17. Propeller speed and phase sensor

    NASA Technical Reports Server (NTRS)

    Collopy, Paul D. (Inventor); Bennett, George W. (Inventor)

    1992-01-01

    A speed and phase sensor counterrotates aircraft propellers. A toothed wheel is attached to each propeller, and the teeth trigger a sensor as they pass, producing a sequence of signals. From the sequence of signals, rotational speed of each propeller is computer based on time intervals between successive signals. The speed can be computed several times during one revolution, thus giving speed information which is highly up-to-date. Given that spacing between teeth may not be uniform, the signals produced may be nonuniform in time. Error coefficients are derived to correct for nonuniformities in the resulting signals, thus allowing accurate speed to be computed despite the spacing nonuniformities. Phase can be viewed as the relative rotational position of one propeller with respect to the other, but measured at a fixed time. Phase is computed from the signals.

  18. The role of spectral composition of sounds on the localization of sound sources by cats.

    PubMed

    Tollin, Daniel J; Ruhland, Janet L; Yin, Tom C T

    2013-03-01

    Sound localization along the azimuthal dimension depends on interaural time and level disparities, whereas localization in elevation depends on broadband power spectra resulting from the filtering properties of the head and pinnae. We trained cats with their heads unrestrained, using operant conditioning to indicate the apparent locations of sounds via gaze shift. Targets consisted of broadband (BB), high-pass (HP), or low-pass (LP) noise, tones from 0.5 to 14 kHz, and 1/6 octave narrow-band (NB) noise with center frequencies ranging from 6 to 16 kHz. For each sound type, localization performance was summarized by the slope of the regression relating actual gaze shift to desired gaze shift. Overall localization accuracy for BB noise was comparable in azimuth and in elevation but was markedly better in azimuth than in elevation for sounds with limited spectra. Gaze shifts to targets in azimuth were most accurate to BB, less accurate for HP, LP, and NB sounds, and considerably less accurate for tones. In elevation, cats were most accurate in localizing BB, somewhat less accurate to HP, and less yet to LP noise (although still with slopes ∼0.60), but they localized NB noise much worse and were unable to localize tones. Deterioration of localization as bandwidth narrows is consistent with the hypothesis that spectral information is critical for sound localization in elevation. For NB noise or tones in elevation, unlike humans, most cats did not have unique responses at different frequencies, and some appeared to respond with a "default" location at all frequencies.

  19. Propagation of sound through a sheared flow

    NASA Technical Reports Server (NTRS)

    Woolley, J. P.; Smith, C. A.; Karamcheti, K.

    1978-01-01

    Sound generated in a moving fluid must propagate through a shear layer in order to be measured by a fixed instrument. These propagation effects were evaluated for noise sources typically associated with single and co-flowing subsonic jets and for subcritical flow over airfoils in such jets. The techniques for describing acoustic propagation fall into two categories: geometric acoustics and wave acoustics. Geometric acoustics is most convenient and accurate for high frequency sound. In the frequency range of interest to the present study (greater than 150 Hz), the geometric acoustics approach was determined to be most useful and practical.

  20. Radiation of sound from unflanged cylindrical ducts

    NASA Technical Reports Server (NTRS)

    Hartharan, S. L.; Bayliss, A.

    1983-01-01

    Calculations of sound radiated from unflanged cylindrical ducts are presented. The numerical simulation models the problem of an aero-engine inlet. The time dependent linearized Euler equations are solved from a state of rest until a harmonic solution is attained. A fourth order accurate finite difference scheme is used and solutions are obtained from a fully vectorized Cyber-203 computer program. Cases of both plane waves and spin modes are treated. Spin modes model the sound generated by a turbofan engine. Boundary conditions for both plane waves and spin modes are treated. Solutions obtained are compared with experiments conducted at NASA Langley Research Center.

  1. Bending sound in graphene: Origin and manifestation

    NASA Astrophysics Data System (ADS)

    Adamyan, V. M.; Bondarev, V. N.; Zavalniuk, V. V.

    2016-11-01

    It is proved that the acoustic-type dispersion of bending mode in graphene is generated by the fluctuation interaction between in-plane and out-of-plane terms in the free energy arising with account of non-linear components in the graphene strain tensor. In doing so we use an original adiabatic approximation based on the alleged (confirmed a posteriori) significant difference of sound speeds for in-plane and bending modes. The explicit expression for the bending sound speed depending only on the graphene mass density, in-plane elastic constants and temperature is deduced as well as the characteristics of the microscopic corrugations of graphene. The obtained results are in good quantitative agreement with the data of real experiments and computer simulations.

  2. 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)

  3. 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…

  4. 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.

  5. 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…

  6. 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…

  7. Dynamic binaural sound localization based on variations of interaural time delays and system rotations.

    PubMed

    Baumann, Claude; Rogers, Chris; Massen, Francis

    2015-08-01

    This work develops the mathematical model for a steerable binaural system that determines the instantaneous direction of a sound source in space. The model combines system angular speed and interaural time delays (ITDs) in a differential equation, which allows monitoring the change of source position in the binaural reference frame and therefore resolves the confusion about azimuth and elevation. The work includes the analysis of error propagation and presents results from a real-time application that was performed on a digital signal processing device. Theory and experiments demonstrate that the azimuthal angle to the sound source is accurately yielded in the case of horizontal rotations, whereas the elevation angle is estimated with large uncertainty. This paper also proves the equivalence of the ITD derivative and the Doppler shift appearing between the binaurally captured audio signals. The equation of this Doppler shift is applicable for any kind of motion. It shows that weak binaural pitch differences may represent an additional cue in localization of sound. Finally, the paper develops practical applications from this relationship, such as the synthesizing of binaural images of pure and complex tones emitted by a moving source, and the generation of multiple frequency images for binaural beat experiments.

  8. Laboratory measurements of the effect of internal waves on sound propagation

    NASA Astrophysics Data System (ADS)

    Zhang, Likun; Swinney, Harry L.; Lin, Ying-Tsong

    2016-11-01

    The fidelity of acoustic signals used in communication and imaging in the oceans is limited by density fluctuations arising from many sources, particularly from internal waves. We present results from laboratory experiments on sound propagation through an internal wave field produced by a wave generator consisting of multiple oscillating plates. The fluid density as a function of height is measured and used to determine the sound speed as a function of the height. Sound pulses from a transducer propagate through the fluctuating stratified density field and are detected to determine sound refraction, pulse arrival time, and sound signal distortion. The results are compared with sound ray model and numerical models of underwater sound propagation. The laboratory experiments can explore the parameter dependence by varying the fluid density profile, the sound pulse signal, and the internal wave amplitude and frequency. The results lead to a better understanding of sound propagation through and scattered by internal waves.

  9. Visualization of sound generation: special imaging techniques

    NASA Astrophysics Data System (ADS)

    Hahlweg, Cornelius F.; Skaloud, Daniel C.; Gutzmann, Holger L.; Kutz, Sascha; Rothe, Hendrik

    2013-09-01

    The present paper is dedicated to the Optics and Music session of the Novel Systems Design and Optimization XVI Conference. It is intended as an informative paper for the music enthusiasts. Included are some examples of visualization of sound generation and vibration modes of musically relevant objects and processes - record playback, an electric guitar and a wine glass - using high speed video, borescopic view and cross polarization techniques.

  10. Accurate quantum chemical calculations

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

    1989-01-01

    An important goal of quantum chemical calculations is to provide an understanding of chemical bonding and molecular electronic structure. A second goal, the prediction of energy differences to chemical accuracy, has been much harder to attain. First, the computational resources required to achieve such accuracy are very large, and second, it is not straightforward to demonstrate that an apparently accurate result, in terms of agreement with experiment, does not result from a cancellation of errors. Recent advances in electronic structure methodology, coupled with the power of vector supercomputers, have made it possible to solve a number of electronic structure problems exactly using the full configuration interaction (FCI) method within a subspace of the complete Hilbert space. These exact results can be used to benchmark approximate techniques that are applicable to a wider range of chemical and physical problems. The methodology of many-electron quantum chemistry is reviewed. Methods are considered in detail for performing FCI calculations. The application of FCI methods to several three-electron problems in molecular physics are discussed. A number of benchmark applications of FCI wave functions are described. Atomic basis sets and the development of improved methods for handling very large basis sets are discussed: these are then applied to a number of chemical and spectroscopic problems; to transition metals; and to problems involving potential energy surfaces. Although the experiences described give considerable grounds for optimism about the general ability to perform accurate calculations, there are several problems that have proved less tractable, at least with current computer resources, and these and possible solutions are discussed.

  11. Wind Speed Measurement by Paper Anemometer

    ERIC Educational Resources Information Center

    Zhong, Juhua; Cheng, Zhongqi; Guan, Wenchuan

    2011-01-01

    A simple wind speed measurement device, a paper anemometer, is fabricated based on the theory of standing waves. In providing the working profile of the paper anemometer, an experimental device is established, which consists of an anemometer sensor, a sound sensor, a microphone, paper strips, a paper cup, and sonic acquisition software. It shows…

  12. Role of spectral detail in sound-source localization.

    PubMed

    Kulkarni, A; Colburn, H S

    Sounds heard over headphones are typically perceived inside the head (internalized), unlike real sound sources which are perceived outside the head (externalized). If the acoustical waveforms from a real sound source are reproduced precisely using headphones, auditory images are appropriately externalized and localized. The filtering (relative boosting, attenuation and delaying of component frequencies) of a sound by the head and outer ear provides information about the location of a sound source by means of the differences in the frequency spectra between the ears as well as the overall spectral shape. This location-dependent filtering is explicitly described by the head-related transfer function (HRTF) from sound source to ear canal. Here we present sounds to subjects through open-canal tube-phones and investigate how accurately the HRTFs must be reproduced to achieve true three-dimensional perception of auditory signals in anechoic space. Listeners attempted to discriminate between 'real' sounds presented from a loudspeaker and 'virtual' sounds presented over tube-phones. Our results show that the HRTFs can be smoothed significantly in frequency without affecting the perceived location of a sound. Listeners cannot distinguish real from virtual sources until the HRTF has lost most of its detailed variation in frequency, at which time the perceived elevation of the image is the reported cue.

  13. 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

  14. Properties of sound attenuation around a two-dimensional underwater vehicle with a large cavitation number

    NASA Astrophysics Data System (ADS)

    Ye, Peng-Cheng; Pan, Guang

    2015-06-01

    Due to the high speed of underwater vehicles, cavitation is generated inevitably along with the sound attenuation when the sound signal traverses through the cavity region around the underwater vehicle. The linear wave propagation is studied to obtain the influence of bubbly liquid on the acoustic wave propagation in the cavity region. The sound attenuation coefficient and the sound speed formula of the bubbly liquid are presented. Based on the sound attenuation coefficients with various vapor volume fractions, the attenuation of sound intensity is calculated under large cavitation number conditions. The result shows that the sound intensity attenuation is fairly small in a certain condition. Consequently, the intensity attenuation can be neglected in engineering. Project supported by the National Natural Science Foundation of China (Grant Nos. 51279165 and 51479170) and the National Defense Basic Scientific Research Program of China (Grant No. B2720133014).

  15. Video indexing based on image and sound

    NASA Astrophysics Data System (ADS)

    Faudemay, Pascal; Montacie, Claude; Caraty, Marie-Jose

    1997-10-01

    Video indexing is a major challenge for both scientific and economic reasons. Information extraction can sometimes be easier from sound channel than from image channel. We first present a multi-channel and multi-modal query interface, to query sound, image and script through 'pull' and 'push' queries. We then summarize the segmentation phase, which needs information from the image channel. Detection of critical segments is proposed. It should speed-up both automatic and manual indexing. We then present an overview of the information extraction phase. Information can be extracted from the sound channel, through speaker recognition, vocal dictation with unconstrained vocabularies, and script alignment with speech. We present experiment results for these various techniques. Speaker recognition methods were tested on the TIMIT and NTIMIT database. Vocal dictation as experimented on newspaper sentences spoken by several speakers. Script alignment was tested on part of a carton movie, 'Ivanhoe'. For good quality sound segments, error rates are low enough for use in indexing applications. Major issues are the processing of sound segments with noise or music, and performance improvement through the use of appropriate, low-cost architectures or networks of workstations.

  16. BIOACCESSIBILITY TESTS ACCURATELY ESTIMATE ...

    EPA Pesticide Factsheets

    Hazards of soil-borne Pb to wild birds may be more accurately quantified if the bioavailability of that Pb is known. To better understand the bioavailability of Pb to birds, we measured blood Pb concentrations in Japanese quail (Coturnix japonica) fed diets containing Pb-contaminated soils. Relative bioavailabilities were expressed by comparison with blood Pb concentrations in quail fed a Pb acetate reference diet. Diets containing soil from five Pb-contaminated Superfund sites had relative bioavailabilities from 33%-63%, with a mean of about 50%. Treatment of two of the soils with P significantly reduced the bioavailability of Pb. The bioaccessibility of the Pb in the test soils was then measured in six in vitro tests and regressed on bioavailability. They were: the “Relative Bioavailability Leaching Procedure” (RBALP) at pH 1.5, the same test conducted at pH 2.5, the “Ohio State University In vitro Gastrointestinal” method (OSU IVG), the “Urban Soil Bioaccessible Lead Test”, the modified “Physiologically Based Extraction Test” and the “Waterfowl Physiologically Based Extraction Test.” All regressions had positive slopes. Based on criteria of slope and coefficient of determination, the RBALP pH 2.5 and OSU IVG tests performed very well. Speciation by X-ray absorption spectroscopy demonstrated that, on average, most of the Pb in the sampled soils was sorbed to minerals (30%), bound to organic matter 24%, or present as Pb sulfate 18%. Ad

  17. 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

  18. 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.

  19. 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

  20. 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

  1. Photoacoustic computed tomography without accurate ultrasonic transducer responses

    NASA Astrophysics Data System (ADS)

    Sheng, Qiwei; Wang, Kun; Xia, Jun; Zhu, Liren; Wang, Lihong V.; Anastasio, Mark A.

    2015-03-01

    Conventional photoacoustic computed tomography (PACT) image reconstruction methods assume that the object and surrounding medium are described by a constant speed-of-sound (SOS) value. In order to accurately recover fine structures, SOS heterogeneities should be quantified and compensated for during PACT reconstruction. To address this problem, several groups have proposed hybrid systems that combine PACT with ultrasound computed tomography (USCT). In such systems, a SOS map is reconstructed first via USCT. Consequently, this SOS map is employed to inform the PACT reconstruction method. Additionally, the SOS map can provide structural information regarding tissue, which is complementary to the functional information from the PACT image. We propose a paradigm shift in the way that images are reconstructed in hybrid PACT-USCT imaging. Inspired by our observation that information about the SOS distribution is encoded in PACT measurements, we propose to jointly reconstruct the absorbed optical energy density and SOS distributions from a combined set of USCT and PACT measurements, thereby reducing the two reconstruction problems into one. This innovative approach has several advantages over conventional approaches in which PACT and USCT images are reconstructed independently: (1) Variations in the SOS will automatically be accounted for, optimizing PACT image quality; (2) The reconstructed PACT and USCT images will possess minimal systematic artifacts because errors in the imaging models will be optimally balanced during the joint reconstruction; (3) Due to the exploitation of information regarding the SOS distribution in the full-view PACT data, our approach will permit high-resolution reconstruction of the SOS distribution from sparse array data.

  2. Genetic optimisation of a plane array geometry for beamforming. Application to source localisation in a high speed train

    NASA Astrophysics Data System (ADS)

    Le Courtois, Florent; Thomas, Jean-Hugh; Poisson, Franck; Pascal, Jean-Claude

    2016-06-01

    Thanks to its easy implementation and robust performance, beamforming is applied for source localisation in several fields. Its effectiveness depends greatly on the array sensor configuration. This paper introduces a criterion to improve the array beampattern and increase the accuracy of sound source localisation. The beamwidth and the maximum sidelobe level are used to quantify the spatial variation of the beampattern through a new criterion. This criterion is shown to be useful, especially for the localisation of moving sources. A genetic algorithm is proposed for the optimisation of microphone placement. Statistical analysis of the optimised arrays provides original results on the algorithm performance and on the optimal microphone placement. An optimised array is tested to localise the sound sources of a high speed train. The results show an accurate separation.

  3. 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

  4. Characterizing, synthesizing, and/or canceling out acoustic signals from sound sources

    DOEpatents

    Holzrichter, John F.; Ng, Lawrence C.

    2007-03-13

    A system for characterizing, synthesizing, and/or canceling out acoustic signals from inanimate and animate sound sources. Electromagnetic sensors monitor excitation sources in sound producing systems, such as animate sound sources such as the human voice, or from machines, musical instruments, and various other structures. Acoustical output from these sound producing systems is also monitored. From such information, a transfer function characterizing the sound producing system is generated. From the transfer function, acoustical output from the sound producing system may be synthesized or canceled. The systems disclosed enable accurate calculation of transfer functions relating specific excitations to specific acoustical outputs. Knowledge of such signals and functions can be used to effect various sound replication, sound source identification, and sound cancellation applications.

  5. Pectoral sound generation in the blue catfish Ictalurus furcatus.

    PubMed

    Mohajer, Yasha; Ghahramani, Zachary; Fine, Michael L

    2015-03-01

    Catfishes produce pectoral stridulatory sounds by "jerk" movements that rub ridges on the dorsal process against the cleithrum. We recorded sound synchronized with high-speed video to investigate the hypothesis that blue catfish Ictalurus furcatus produce sounds by a slip-stick mechanism, previously described only in invertebrates. Blue catfish produce a variably paced series of sound pulses during abduction sweeps (pulsers) although some individuals (sliders) form longer duration sound units (slides) interspersed with pulses. Typical pulser sounds are evoked by short 1-2 ms movements with a rotation of 2°-3°. Jerks excite sounds that increase in amplitude after motion stops, suggesting constructive interference, which decays before the next jerk. Longer contact of the ridges produces a more steady-state sound in slides. Pulse pattern during stridulation is determined by pauses without movement: the spine moves during about 14 % of the abduction sweep in pulsers (~45 % in sliders) although movement appears continuous to the human eye. Spine rotation parameters do not predict pulse amplitude, but amplitude correlates with pause duration suggesting that force between the dorsal process and cleithrum increases with longer pauses. Sound production, stimulated by a series of rapid movements that set the pectoral girdle into resonance, is caused by a slip-stick mechanism.

  6. Accurate spectral color measurements

    NASA Astrophysics Data System (ADS)

    Hiltunen, Jouni; Jaeaeskelaeinen, Timo; Parkkinen, Jussi P. S.

    1999-08-01

    Surface color measurement is of importance in a very wide range of industrial applications including paint, paper, printing, photography, textiles, plastics and so on. For a demanding color measurements spectral approach is often needed. One can measure a color spectrum with a spectrophotometer using calibrated standard samples as a reference. Because it is impossible to define absolute color values of a sample, we always work with approximations. The human eye can perceive color difference as small as 0.5 CIELAB units and thus distinguish millions of colors. This 0.5 unit difference should be a goal for the precise color measurements. This limit is not a problem if we only want to measure the color difference of two samples, but if we want to know in a same time exact color coordinate values accuracy problems arise. The values of two instruments can be astonishingly different. The accuracy of the instrument used in color measurement may depend on various errors such as photometric non-linearity, wavelength error, integrating sphere dark level error, integrating sphere error in both specular included and specular excluded modes. Thus the correction formulas should be used to get more accurate results. Another question is how many channels i.e. wavelengths we are using to measure a spectrum. It is obvious that the sampling interval should be short to get more precise results. Furthermore, the result we get is always compromise of measuring time, conditions and cost. Sometimes we have to use portable syste or the shape and the size of samples makes it impossible to use sensitive equipment. In this study a small set of calibrated color tiles measured with the Perkin Elmer Lamda 18 and the Minolta CM-2002 spectrophotometers are compared. In the paper we explain the typical error sources of spectral color measurements, and show which are the accuracy demands a good colorimeter should have.

  7. Detection of Sound Image Movement During Horizontal Head Rotation

    PubMed Central

    Ohba, Kagesho; Iwaya, Yukio; Suzuki, Yôiti

    2016-01-01

    Movement detection for a virtual sound source was measured during the listener’s horizontal head rotation. Listeners were instructed to do head rotation at a given speed. A trial consisted of two intervals. During an interval, a virtual sound source was presented 60° to the right or left of the listener, who was instructed to rotate the head to face the sound image position. Then in one of a pair of intervals, the sound position was moved slightly in the middle of the rotation. Listeners were asked to judge the interval in a trial during which the sound stimuli moved. Results suggest that detection thresholds are higher when listeners do head rotation. Moreover, this effect was found to be independent of the rotation velocity. PMID:27698993

  8. Sound-symbolism boosts novel word learning.

    PubMed

    Lockwood, Gwilym; Dingemanse, Mark; Hagoort, Peter

    2016-08-01

    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 information, to investigate how sensitive Dutch speakers are to sound-symbolism in Japanese in a learning task. Participants were taught 2 sets of Japanese ideophones; 1 set with the ideophones' real meanings in Dutch, the other set with their opposite meanings. In Experiment 1, participants learned the ideophones and their real meanings much better than the ideophones with their opposite meanings. Moreover, despite the learning rounds, participants were still able to guess the real meanings of the ideophones in a 2-alternative forced-choice test after they were informed of the manipulation. This shows that natural language sound-symbolism is robust beyond 2-alternative forced-choice paradigms and affects broader language processes such as word learning. In Experiment 2, participants learned regular Japanese adjectives with the same manipulation, and there was no difference between real and opposite conditions. This shows that natural language sound-symbolism is especially strong in ideophones, and that people learn words better when form and meaning match. The highlights of this study are as follows: (a) Dutch speakers learn real meanings of Japanese ideophones better than opposite meanings, (b) Dutch speakers accurately guess meanings of Japanese ideophones, (c) this sensitivity happens despite learning some opposite pairings, (d) no such learning effect exists for regular Japanese adjectives, and (e) this shows the importance of sound-symbolism in scaffolding language learning. (PsycINFO Database Record

  9. 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)

  10. 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)

  11. 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

  12. 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.

  13. Sound Speed Structure of the Western South Atlantic Ocean.

    DTIC Science & Technology

    1982-07-01

    through and in the environs of the Vema Channel is discussed in detail by Johnson, McDowell, Sullivan, and Biscayne (1976). The presence of AABW would also...71), August, 185 p. Johnson, D. A., S. E, McDowell, L. G. Sullivan, and P. E. Biscayne (1976). Abyssal Hydrography, Nephelometry, Currents, and Benthic...TAEAS) (1) 540 Ocean Measurements (1) 550 Mapping, Charting & Geodesy Program (1) ONRDET Director, ONR Science & Technology Detachment, Bay St. Louis

  14. CHORDS: A New Temperature or Sound Speed Profile Thinning Algorithm.

    DTIC Science & Technology

    1984-05-01

    applications while reducing the number of profile points by a factor of 10. A zero value of the tolerance limit will force the subroutine to halt the...subroutine, a zero value will be returned for the number of output points (NR). 11LANK 11. DETAILED FUNCTIONAL DESCRIPTION In the following...REAL INTERP 0043 DIMENSION DIFF(MPNTS),NUM(MPNTS) 0044 DATA DIFFLT/-999V9./ 0045 NOLINuMPNTS-1 0046 C 0047 C ZERO ARRAYS 0048 C 0049 DO 9999 J=.,MPNTS

  15. Bearing Stake Exercise: Sound Speed and other Environmental Variability

    DTIC Science & Technology

    1978-09-01

    xwas sex eral meters-pcr- econd higher than that for other exercise sites, cansed by hinh salinit) PGI\\M aur RSIW in a ielatixely unmixed form. The...NAVAL OCEAN SYSTEMS CENTER IV SAN DIEGO, CALIF~ORNIA 92152 k; [ ¶ NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY NST L Station, Mississippi 39529...9 -- ’Ž CO~NFD TAL CONFID[NTIAL FOREWORD (C) The BEARING STAKE Exercise was. conducted by the Naval Ocean Systems Center (NOSC) under the

  16. Time-of-Flight Measurement of Sound Speed in Air

    ERIC Educational Resources Information Center

    Ganci, Salvatore

    2011-01-01

    This paper describes a set of simple experiments with a very low cost using a notebook as a measuring instrument without external hardware. The major purpose is to provide demonstration experiments for schools with very low budgets. (Contains 6 figures.)

  17. 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

  18. 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.

  19. Sound localization and auditory response capabilities in round goby (Neogobius melanostomus)

    NASA Astrophysics Data System (ADS)

    Rollo, Audrey K.; Higgs, Dennis M.

    2005-04-01

    A fundamental role in vertebrate auditory systems is determining the direction of a sound source. While fish show directional responses to sound, sound localization remains in dispute. The species used in the current study, Neogobius melanostomus (round goby) uses sound in reproductive contexts, with both male and female gobies showing directed movement towards a calling male. The two-choice laboratory experiment was used (active versus quiet speaker) to analyze behavior of gobies in response to sound stimuli. When conspecific male spawning sounds were played, gobies moved in a direct path to the active speaker, suggesting true localization to sound. Of the animals that responded to conspecific sounds, 85% of the females and 66% of the males moved directly to the sound source. Auditory playback of natural and synthetic sounds showed differential behavioral specificity. Of gobies that responded, 89% were attracted to the speaker playing Padogobius martensii sounds, 87% to 100 Hz tone, 62% to white noise, and 56% to Gobius niger sounds. Swimming speed, as well as mean path angle to the speaker, will be presented during the presentation. Results suggest a strong localization of the round goby to a sound source, with some differential sound specificity.

  20. 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.

  1. Amplitude modulation of sound from wind turbines under various meteorological conditions.

    PubMed

    Larsson, Conny; Öhlund, Olof

    2014-01-01

    Wind turbine (WT) sound annoys some people even though the sound levels are relatively low. This could be because of the amplitude modulated "swishing" characteristic of the turbine sound, which is not taken into account by standard procedures for measuring average sound levels. Studies of sound immission from WTs were conducted continually between 19 August 2011 and 19 August 2012 at two sites in Sweden. A method for quantifying the degree and strength of amplitude modulation (AM) is introduced here. The method reveals that AM at the immission points occur under specific meteorological conditions. For WT sound immission, the wind direction and sound speed gradient are crucial for the occurrence of AM. Interference between two or more WTs could probably enhance AM. The mechanisms by which WT sound is amplitude modulated are not fully understood.

  2. Opponent Coding of Sound Location (Azimuth) in Planum Temporale is Robust to Sound-Level Variations.

    PubMed

    Derey, Kiki; Valente, Giancarlo; de Gelder, Beatrice; Formisano, Elia

    2016-01-01

    Coding of sound location in auditory cortex (AC) is only partially understood. Recent electrophysiological research suggests that neurons in mammalian auditory cortex are characterized by broad spatial tuning and a preference for the contralateral hemifield, that is, a nonuniform sampling of sound azimuth. Additionally, spatial selectivity decreases with increasing sound intensity. To accommodate these findings, it has been proposed that sound location is encoded by the integrated activity of neuronal populations with opposite hemifield tuning ("opponent channel model"). In this study, we investigated the validity of such a model in human AC with functional magnetic resonance imaging (fMRI) and a phase-encoding paradigm employing binaural stimuli recorded individually for each participant. In all subjects, we observed preferential fMRI responses to contralateral azimuth positions. Additionally, in most AC locations, spatial tuning was broad and not level invariant. We derived an opponent channel model of the fMRI responses by subtracting the activity of contralaterally tuned regions in bilateral planum temporale. This resulted in accurate decoding of sound azimuth location, which was unaffected by changes in sound level. Our data thus support opponent channel coding as a neural mechanism for representing acoustic azimuth in human AC.

  3. Measuring the speed of dark: Detecting dark energy perturbations

    SciTech Connect

    Putter, Roland de; Huterer, Dragan; Linder, Eric V.

    2010-05-15

    The nature of dark energy can be probed not only through its equation of state but also through its microphysics, characterized by the sound speed of perturbations to the dark energy density and pressure. As the sound speed drops below the speed of light, dark energy inhomogeneities increase, affecting both cosmic microwave background and matter power spectra. We show that current data can put no significant constraints on the value of the sound speed when dark energy is purely a recent phenomenon, but can begin to show more interesting results for early dark energy models. For example, the best fit model for current data has a slight preference for dynamics [w(a){ne}-1], degrees of freedom distinct from quintessence (c{sub s{ne}}1), and early presence of dark energy [{Omega}{sub de}(a<<1){ne}0]. Future data may open a new window on dark energy by measuring its spatial as well as time variation.

  4. Sound-burst Generator for Measuring Coal Properties

    NASA Technical Reports Server (NTRS)

    Hadden, W. J. J.; Mills, J. M.; Pierce, A. D.

    1982-01-01

    Acoustical properties of coal can be measured accurately and with relative ease with aid of digital two-channel sine-wave sound generator. Generator is expected to provide information for development of acoustic devices for measuring thickness of coal in longwall mining. In echo-cancellation measurements, sound bursts are sent to coal sample from opposite directions. Transmitted and reflected amplitudes and phases are measured by transducers to determine coal properties.

  5. The Avian Head Induces Cues for Sound Localization in Elevation

    PubMed Central

    Schnyder, Hans A.; Vanderelst, Dieter; Bartenstein, Sophia; Firzlaff, Uwe; Luksch, Harald

    2014-01-01

    Accurate sound source localization in three-dimensional space is essential for an animal’s orientation and survival. While the horizontal position can be determined by interaural time and intensity differences, localization in elevation was thought to require external structures that modify sound before it reaches the tympanum. Here we show that in birds even without external structures like pinnae or feather ruffs, the simple shape of their head induces sound modifications that depend on the elevation of the source. Based on a model of localization errors, we show that these cues are sufficient to locate sounds in the vertical plane. These results suggest that the head of all birds induces acoustic cues for sound localization in the vertical plane, even in the absence of external ears. PMID:25390036

  6. Deterministic prediction of surface wind speed variations

    NASA Astrophysics Data System (ADS)

    Drisya, G. V.; Kiplangat, D. C.; Asokan, K.; Satheesh Kumar, K.

    2014-11-01

    Accurate prediction of wind speed is an important aspect of various tasks related to wind energy management such as wind turbine predictive control and wind power scheduling. The most typical characteristic of wind speed data is its persistent temporal variations. Most of the techniques reported in the literature for prediction of wind speed and power are based on statistical methods or probabilistic distribution of wind speed data. In this paper we demonstrate that deterministic forecasting methods can make accurate short-term predictions of wind speed using past data, at locations where the wind dynamics exhibit chaotic behaviour. The predictions are remarkably accurate up to 1 h with a normalised RMSE (root mean square error) of less than 0.02 and reasonably accurate up to 3 h with an error of less than 0.06. Repeated application of these methods at 234 different geographical locations for predicting wind speeds at 30-day intervals for 3 years reveals that the accuracy of prediction is more or less the same across all locations and time periods. Comparison of the results with f-ARIMA model predictions shows that the deterministic models with suitable parameters are capable of returning improved prediction accuracy and capturing the dynamical variations of the actual time series more faithfully. These methods are simple and computationally efficient and require only records of past data for making short-term wind speed forecasts within practically tolerable margin of errors.

  7. 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.

  8. Pervasive Sound Sensing: A Weakly Supervised Training Approach.

    PubMed

    Kelly, Daniel; Caulfield, Brian

    2016-01-01

    Modern smartphones present an ideal device for pervasive sensing of human behavior. Microphones have the potential to reveal key information about a person's behavior. However, they have been utilized to a significantly lesser extent than other smartphone sensors in the context of human behavior sensing. We postulate that, in order for microphones to be useful in behavior sensing applications, the analysis techniques must be flexible and allow easy modification of the types of sounds to be sensed. A simplification of the training data collection process could allow a more flexible sound classification framework. We hypothesize that detailed training, a prerequisite for the majority of sound sensing techniques, is not necessary and that a significantly less detailed and time consuming data collection process can be carried out, allowing even a nonexpert to conduct the collection, labeling, and training process. To test this hypothesis, we implement a diverse density-based multiple instance learning framework, to identify a target sound, and a bag trimming algorithm, which, using the target sound, automatically segments weakly labeled sound clips to construct an accurate training set. Experiments reveal that our hypothesis is a valid one and results show that classifiers, trained using the automatically segmented training sets, were able to accurately classify unseen sound samples with accuracies comparable to supervised classifiers, achieving an average F -measure of 0.969 and 0.87 for two weakly supervised datasets.

  9. Annoyance caused by the sounds of a magnetic levitation train.

    PubMed

    Vos, Joos

    2004-04-01

    In a laboratory study, the annoyance caused by the passby sounds from a magnetic levitation (maglev) train was investigated. The listeners were presented with various sound fragments. The task of the listeners was to respond after each presentation to the question: "How annoying would you find the sound in the preceding period if you were exposed to it at home on a regular basis?" The independent variables were (a) the driving speed of the maglev train (varying from 100 to 400 km/h), (b) the outdoor A-weighted sound exposure level (ASEL) of the passbys (varying from 65 to 90 dB), and (c) the simulated outdoor-to-indoor reduction in sound level (windows open or windows closed). As references to the passby sounds from the maglev train (type Transrapid 08), sounds from road traffic (passenger cars and trucks) and more conventional railway (intercity trains) were included for rating also. Four important results were obtained. Provided that the outdoor ASELs were the same, (1) the annoyance was independent of the driving speed of the maglev train, (2) the annoyance caused by the maglev train was considerably higher than that caused by the intercity train, (3) the annoyance caused by the maglev train was hardly different from that caused by road traffic, and (4) the results (1)-(3) held true both for open or closed windows. On the basis of the present results, it might be expected that the sounds are equally annoying if the ASELs of the maglev-train passbys are at least 5 dB lower than those of the intercity train passbys. Consequently, the results of the present experiment do not support application of a railway bonus to the maglev-train sounds.

  10. High speed packet switching

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This document constitutes the final report prepared by Proteon, Inc. of Westborough, Massachusetts under contract NAS 5-30629 entitled High-Speed Packet Switching (SBIR 87-1, Phase 2) prepared for NASA-Greenbelt, Maryland. The primary goal of this research project is to use the results of the SBIR Phase 1 effort to develop a sound, expandable hardware and software router architecture capable of forwarding 25,000 packets per second through the router and passing 300 megabits per second on the router's internal busses. The work being delivered under this contract received its funding from three different sources: the SNIPE/RIG contract (Contract Number F30602-89-C-0014, CDRL Sequence Number A002), the SBIR contract, and Proteon. The SNIPE/RIG and SBIR contracts had many overlapping requirements, which allowed the research done under SNIPE/RIG to be applied to SBIR. Proteon funded all of the work to develop new router interfaces other than FDDI, in addition to funding the productization of the router itself. The router being delivered under SBIR will be a fully product-quality machine. The work done during this contract produced many significant findings and results, summarized here and explained in detail in later sections of this report. The SNIPE/RIG contract was completed. That contract had many overlapping requirements with the SBIR contract, and resulted in the successful demonstration and delivery of a high speed router. The development that took place during the SNIPE/RIG contract produced findings that included the choice of processor and an understanding of the issues surrounding inter processor communications in a multiprocessor environment. Many significant speed enhancements to the router software were made during that time. Under the SBIR contract (and with help from Proteon-funded work), it was found that a single processor router achieved a throughput significantly higher than originally anticipated. For this reason, a single processor router was

  11. Atmospheric sound propagation

    NASA Technical Reports Server (NTRS)

    Cook, R. K.

    1969-01-01

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

  12. Acoustic model of micro-pressure wave emission from a high-speed train tunnel

    NASA Astrophysics Data System (ADS)

    Miyachi, T.

    2017-03-01

    The micro-pressure wave (MPW) radiated from a tunnel portal can, if audible, cause serious problems around tunnel portals in high-speed railways. This has created a need to develop an acoustic model that considers the topography around a radiation portal in order to predict MPWs more accurately and allow for higher speed railways in the future. An acoustic model of MPWs based on linear acoustic theory is developed in this study. First, the directivity of sound sources and the acoustical effect of topography are investigated using a train launcher facility around a portal on infinitely flat ground and with an infinite vertical baffle plate. The validity of linear acoustic theory is then discussed through a comparison of numerical results obtained using the finite difference method (FDM) and experimental results. Finally, an acoustic model is derived that considers sound sources up to the second order and Green's function to represent the directivity and effect of topography, respectively. The results predicted by this acoustic model are shown to be in good agreement with both numerical and experimental results.

  13. 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.

  14. Perception of speech sounds in school-age children with speech sound disorders

    PubMed Central

    Preston, Jonathan L.; Irwin, Julia R.; Turcios, Jacqueline

    2015-01-01

    Children with speech sound disorders may perceive speech differently than children with typical speech development. The nature of these speech differences is reviewed with an emphasis on assessing phoneme-specific perception for speech sounds that are produced in error. Category goodness judgment, or the ability to judge accurate and inaccurate tokens of speech sounds, plays an important role in phonological development. The software Speech Assessment and Interactive Learning System (Rvachew, 1994), which has been effectively used to assess preschoolers’ ability to perform goodness judgments, is explored for school-age children with residual speech errors (RSE). However, data suggest that this particular task may not be sensitive to perceptual differences in school-age children. The need for the development of clinical tools for assessment of speech perception in school-age children with RSE is highlighted, and clinical suggestions are provided. PMID:26458198

  15. Perception of Speech Sounds in School-Aged Children with Speech Sound Disorders.

    PubMed

    Preston, Jonathan L; Irwin, Julia R; Turcios, Jacqueline

    2015-11-01

    Children with speech sound disorders may perceive speech differently than children with typical speech development. The nature of these speech differences is reviewed with an emphasis on assessing phoneme-specific perception for speech sounds that are produced in error. Category goodness judgment, or the ability to judge accurate and inaccurate tokens of speech sounds, plays an important role in phonological development. The software Speech Assessment and Interactive Learning System, which has been effectively used to assess preschoolers' ability to perform goodness judgments, is explored for school-aged children with residual speech errors (RSEs). However, data suggest that this particular task may not be sensitive to perceptual differences in school-aged children. The need for the development of clinical tools for assessment of speech perception in school-aged children with RSE is highlighted, and clinical suggestions are provided.

  16. Transient Sound Intensity Measurements for Evaluating the Spatial Information of Sound Fields in Reverberant Enclosures.

    NASA Astrophysics Data System (ADS)

    Abdov, Adel Abdel-Moneim

    Over the last twenty years, new subjectively relevant objective room-acoustic indicators for evaluating the acoustical quality of an enclosure have been introduced. While these indicators give new insight into the acoustical "Goodness" of a listener position, in order to design halls, assess or to correct an acoustical defect in an existing enclosure, there is a need to understand to what extent they are influenced by the physical design features of the enclosure. To meet such a need, information about the directional characteristics of sound is required. The spatial distribution of sound energy is usually not considered due to lack of an efficient, accurate and easy to perform measurement method. The main objectives of the present study are, first; to review known and speculative room-acoustic indicators for use in assessing reverberant spaces such as concert halls, opera houses, multi-purpose halls and churches. Second, to introduce an easy to perform measurement method for directional sensing in sound fields. Third, to develop a simple and inexpensive PC-based instrument primarily for the measurement of sound fields directional characteristics as well as contemporary room-acoustic indicators. Fourth, to propose new room-acoustic indicators which have relevance to directional information. This study introduces a three-dimensional sound intensity measurement technique for obtaining spatial information of sound fields in an enclosure. The technique has been validated and its accuracy investigated. The method gives results that provide valuable information regarding the directional behaviour of sound in enclosures. Subsequently both the system and the measurement method were applied to known spaces as example applications in order to assess sound quality, to detect the effect of the surrounding interior features of the space, and to assess potential diagnostic capability with respect to interior physical changes. The study has validated the measurement procedure as

  17. 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.

  18. The Audible Human Project: Modeling Sound Transmission in the Lungs and Torso

    NASA Astrophysics Data System (ADS)

    Dai, Zoujun

    Auscultation has been used qualitatively by physicians for hundreds of years to aid in the monitoring and diagnosis of pulmonary diseases. Alterations in the structure and function of the pulmonary system that occur in disease or injury often give rise to measurable changes in lung sound production and transmission. Numerous acoustic measurements have revealed the differences of breath sounds and transmitted sounds in the lung under normal and pathological conditions. Compared to the extensive cataloging of lung sound measurements, the mechanism of sound transmission in the pulmonary system and how it changes with alterations of lung structural and material properties has received less attention. A better understanding of sound transmission and how it is altered by injury and disease might improve interpretation of lung sound measurements, including new lung imaging modalities that are based on an array measurement of the acoustic field on the torso surface via contact sensors or are based on a 3-dimensional measurement of the acoustic field throughout the lungs and torso using magnetic resonance elastography. A long-term goal of the Audible Human Project (AHP ) is to develop a computational acoustic model that would accurately simulate generation, transmission and noninvasive measurement of sound and vibration within the pulmonary system and torso caused by both internal (e.g. respiratory function) and external (e.g. palpation) sources. The goals of this dissertation research, fitting within the scope of the AHP, are to develop specific improved theoretical understandings, computational algorithms and experimental methods aimed at transmission and measurement. The research objectives undertaken in this dissertation are as follows. (1) Improve theoretical modeling and experimental identification of viscoelasticity in soft biological tissues. (2) Develop a poroviscoelastic model for lung tissue vibroacoustics. (3) Improve lung airway acoustics modeling and its

  19. Sound. Physical Science in Action[TM]. Schlessinger Science Library. [Videotape].

    ERIC Educational Resources Information Center

    2000

    A door closes. A horn beeps. A crowd roars. Sound waves travel outward in all directions from the source. They can all be heard, but how? Did they travel directly to the ears? Perhaps they bounced off another object first or traveled through a different medium, changing speed along the way. Students learn how sound waves travel and about their…

  20. Sound Radiated by a Wave-Like Structure in a Compressible Jet

    NASA Technical Reports Server (NTRS)

    Golubev, V. V.; Prieto, A. F.; Mankbadi, R. R.; Dahl, M. D.; Hixon, R.

    2003-01-01

    This paper extends the analysis of acoustic radiation from the source model representing spatially-growing instability waves in a round jet at high speeds. Compared to previous work, a modified approach to the sound source modeling is examined that employs a set of solutions to linearized Euler equations. The sound radiation is then calculated using an integral surface method.

  1. Dispersion of sound in a combustion duct by fuel droplets and soot particles

    NASA Technical Reports Server (NTRS)

    Miles, J. H.; Raftopoulos, D. D.

    1979-01-01

    Dispersion and attenuation of acoustic plane wave disturbances propagating in a ducted combustion system are studied. The dispersion and attenuation are caused by fuel droplet and soot emissions from a jet engine combustor. The attenuation and dispersion are due to heat transfer and mass transfer and viscous drag forces between the emissions and the ambient gas. Theoretical calculations show sound propagation at speeds below the isentropic speed of sound at low frequencies. Experimental results are in good agreement with the theory.

  2. Can anti-speeding messages based on protection motivation theory influence reported speeding intentions?

    PubMed

    Glendon, A Ian; Walker, Britta L

    2013-08-01

    The study investigated the effects of anti-speeding messages based on protection motivation theory (PMT) components: severity, vulnerability, rewards, self-efficacy, response efficacy, and response cost, on reported speeding intentions. Eighty-three participants aged 18-25 years holding a current Australian driver's license completed a questionnaire measuring their reported typical and recent speeding behaviors. Comparisons were made between 18 anti-speeding messages used on Australian roads and 18 new anti-speeding messages developed from the PMT model. Participants reported their reactions to the 36 messages on the perceived effectiveness of the message for themselves and for the general population of drivers, and also the likelihood of themselves and other drivers driving within the speed limit after viewing each message. Overall the PMT model-derived anti-speeding messages were better than jurisdiction-use anti-speeding messages in influencing participants' reported intention to drive within the speed limit. Severity and vulnerability were the most effective PMT components for developing anti-speeding messages. Male participants reported significantly lower intention to drive within the speed limit than did female participants. However, males reported significantly higher intention to drive within the speed limit for PMT-derived messages compared with jurisdiction-based messages. Third-person effects were that males reported anti-speeding messages to be more effective for the general driving population than for themselves. Females reported the opposite effect - that all messages would be more effective for themselves than for the general driving population. Findings provided support for using a sound conceptual basis as an effective foundation for anti-speeding message development as well as for evaluating proposed anti-speeding messages on the target driver population.

  3. Merged Sounding VAP Version 2.0

    SciTech Connect

    Troyan, D.; Jensen, M.; Turner, D.; Miloshevich, L.

    2010-03-15

    The Merged Sounding Value-Added Product (VAP) has been in the ARM and ASR pipeline since 2001. Output data streams have been added to the Evaluation Products section of the ARM website for the past five years. Currently, there are data for all of the ACRF fixed sites and all deployments of the Mobile Facility. Fifty-three years of Merged Sounding data is available as an evaluation product. The process of moving all to the ARM Data Archive has been started and will be completed shortly. A second version of the Merged Sounding VAP was developed to address several concerns: (1) Vaisala radiosondes have inherent problems obtaining an accurate measurement of relative humidity, (2) the profile can be extended from 20 km to 60 km above ground level based upon the height achieved by ECMWF profiles, and (3) ECMWF temperatures require adjustments at high altitude (between 1mb and 100 mb). Solutions to these issues have been incorporated in the new version of this VAP. Along with producing that second version of Merged Sounding, a secondary data stream - Sonde Adjust - was created. This VAP incorporates any humidity corrections to the Vaisala RS-80, RS-90, and RS-92 radiosondes. The algorithms used to perform these corrections are documented by Wang et. al. (2002), Turner et. al. (2003), and Miloshevich et. al. (2004, 2009).

  4. 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…

  5. 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)

  6. 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…

  7. 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,…

  8. 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.

  9. 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.

  10. Underwater sound of rigid-hulled inflatable boats.

    PubMed

    Erbe, Christine; Liong, Syafrin; Koessler, Matthew Walter; Duncan, Alec J; Gourlay, Tim

    2016-06-01

    Underwater sound of rigid-hulled inflatable boats was recorded 142 times in total, over 3 sites: 2 in southern British Columbia, Canada, and 1 off Western Australia. Underwater sound peaked between 70 and 400 Hz, exhibiting strong tones in this frequency range related to engine and propeller rotation. Sound propagation models were applied to compute monopole source levels, with the source assumed 1 m below the sea surface. Broadband source levels (10-48 000 Hz) increased from 134 to 171 dB re 1 μPa @ 1 m with speed from 3 to 16 m/s (10-56 km/h). Source power spectral density percentile levels and 1/3 octave band levels are given for use in predictive modeling of underwater sound of these boats as part of environmental impact assessments.

  11. Sound of a cup with and without instant coffee

    NASA Astrophysics Data System (ADS)

    Morrison, Andrew; Rossing, Thomas D.

    2002-05-01

    An empty coffee cup, like an ancient Chinese two-tone bell, emits two distinctly different tones, depending upon where it is tapped. When it is filled with hot water, and some instant coffee is added, however, a whole new set of sounds is heard when the cup is tapped. The pitch rises an octave or more as the foam clears due to the dramatic change in the speed of sound in the bubble-filled liquid. A similar, but smaller, effect was noted in beer by Bragg [The World of Sound (1968)] and in hot chocolate by Crawford [Am. J. Phys. (1982)]. We describe the modes of vibration in a coffee cup and the sound emitted by a coffee cup as filled with instant coffee as the bubble density changes.

  12. 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.

  13. Unusual sound production mechanism in the triggerfish Rhinecanthus aculeatus (Balistidae).

    PubMed

    Parmentier, Eric; Raick, Xavier; Lecchini, David; Boyle, Kelly; Van Wassenbergh, Sam; Bertucci, Frédéric; Kéver, Loïc

    2017-01-15

    The ability to produce sound has been known for decades in Balistidae. Sounds of many species have been recorded and a variety of sound-producing mechanisms have been proposed, including teeth stridulation, collision of the buccal teeth and movements of the fins. The best-supported hypothesis involves movements of the pectoral fin against the lateral part of the swimbladder, called a drumming membrane. In this study, we describe for the first time the sounds made by the blackbar triggerfish Rhinecanthus aculeatus, which are like short drum rolls with an average duration of 85 ms, 193 Hz dominant frequency and 136 dB SPL level at 3 cm distance. The sounds are a series of pulses that result from alternate sweeping movements of the right and left pectoral fins, which push a system of three scutes that are forced against the swimbladder wall. Pulses from each fin occur in consecutive pairs. High-speed videos indicate that each pulse consists of two cycles. The first part of each cycle corresponds to the inward buckling of the scutes, whereas the second part of the cycle corresponds to an apparent passive recoil of the scutes and swimbladder wall. This novel sound production mechanism is probably found in many members of Balistidae because these peculiar scutes occur in other species in the family. Comparison of sound characteristics from fishes of different sizes shows that dominant frequency decreases with size in juveniles but not in adults.

  14. What the Toadfish Ear Tells the Toadfish Brain About Sound.

    PubMed

    Edds-Walton, Peggy L

    2016-01-01

    Of the three, paired otolithic endorgans in the ear of teleost fishes, the saccule is the one most often demonstrated to have a major role in encoding frequencies of biologically relevant sounds. The toadfish saccule also encodes sound level and sound source direction in the phase-locked activity conveyed via auditory afferents to nuclei of the ipsilateral octaval column in the medulla. Although paired auditory receptors are present in teleost fishes, binaural processes were believed to be unimportant due to the speed of sound in water and the acoustic transparency of the tissues in water. In contrast, there are behavioral and anatomical data that support binaural processing in fishes. Studies in the toadfish combined anatomical tract-tracing and physiological recordings from identified sites along the ascending auditory pathway to document response characteristics at each level. Binaural computations in the medulla and midbrain sharpen the directional information provided by the saccule. Furthermore, physiological studies in the central nervous system indicated that encoding frequency, sound level, temporal pattern, and sound source direction are important components of what the toadfish ear tells the toadfish brain about sound.

  15. 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'…

  16. 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…

  17. 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…

  18. Data sonification and sound visualization.

    SciTech Connect

    Kaper, H. G.; Tipei, S.; Wiebel, E.; Mathematics and Computer Science; Univ. of Illinois

    1999-07-01

    Sound can help us explore and analyze complex data sets in scientific computing. The authors describe a digital instrument for additive sound synthesis (Diass) and a program to visualize sounds in a virtual reality environment (M4Cave). Both are part of a comprehensive music composition environment that includes additional software for computer-assisted composition and automatic music notation.

  19. Environmentally sound manufacturing

    NASA 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. Simulation of sound propagation over porous barriers of arbitrary shapes.

    PubMed

    Ke, Guoyi; Zheng, Z C

    2015-01-01

    A time-domain solver using an immersed boundary method is investigated for simulating sound propagation over porous and rigid barriers of arbitrary shapes. In this study, acoustic propagation in the air from an impulse source over the ground is considered as a model problem. The linearized Euler equations are solved for sound propagation in the air and the Zwikker-Kosten equations for propagation in barriers as well as in the ground. In comparison to the analytical solutions, the numerical scheme is validated for the cases of a single rigid barrier with different shapes and for two rigid triangular barriers. Sound propagations around barriers with different porous materials are then simulated and discussed. The results show that the simulation is able to capture the sound propagation behaviors accurately around both rigid and porous barriers.

  10. Learning and Generalization on Asynchrony and Order Tasks at Sound Offset: Implications for Underlying Neural Circuitry

    ERIC Educational Resources Information Center

    Mossbridge, Julia A.; Scissors, Beth N.; Wright, Beverly A.

    2008-01-01

    Normal auditory perception relies on accurate judgments about the temporal relationships between sounds. Previously, we used a perceptual-learning paradigm to investigate the neural substrates of two such relative-timing judgments made at sound onset: detecting stimulus asynchrony and discriminating stimulus order. Here, we conducted parallel…

  11. Auditory and Cognitive Effects of Aging on Perception of Environmental Sounds in Natural Auditory Scenes

    ERIC Educational Resources Information Center

    Gygi, Brian; Shafiro, Valeriy

    2013-01-01

    Purpose: Previously, Gygi and Shafiro (2011) found that when environmental sounds are semantically incongruent with the background scene (e.g., horse galloping in a restaurant), they can be identified more accurately by young normal-hearing listeners (YNH) than sounds congruent with the scene (e.g., horse galloping at a racetrack). This study…

  12. Accurate Evaluation of Quantum Integrals

    NASA Technical Reports Server (NTRS)

    Galant, D. C.; Goorvitch, D.; Witteborn, Fred C. (Technical Monitor)

    1995-01-01

    Combining an appropriate finite difference method with Richardson's extrapolation results in a simple, highly accurate numerical method for solving a Schrodinger's equation. Important results are that error estimates are provided, and that one can extrapolate expectation values rather than the wavefunctions to obtain highly accurate expectation values. We discuss the eigenvalues, the error growth in repeated Richardson's extrapolation, and show that the expectation values calculated on a crude mesh can be extrapolated to obtain expectation values of high accuracy.

  13. 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.

  14. Topological speed limits to network synchronization.

    PubMed

    Timme, Marc; Wolf, Fred; Geisel, Theo

    2004-02-20

    We study collective synchronization of pulse-coupled oscillators interacting on asymmetric random networks. We demonstrate that random matrix theory can be used to accurately predict the speed of synchronization in such networks in dependence on the dynamical and network parameters. Furthermore, we show that the speed of synchronization is limited by the network connectivity and remains finite, even if the coupling strength becomes infinite. In addition, our results indicate that synchrony is robust under structural perturbations of the network dynamics.

  15. Perceiving and reenacting spatiotemporal characteristics of walking sounds.

    PubMed

    Young, William; Rodger, Matthew; Craig, Cathy M

    2013-04-01

    Many studies have examined the processes involved in recognizing types of human action through sound, but little is known about whether the physical characteristics of an action (such as kinetic and kinematic parameters) can be perceived and imitated from sound. Twelve young healthy adults listened to recordings of footsteps on a gravel path taken from walks of different stride lengths (SL) and cadences. In 1 protocol, participants performed a real-time reenactment of the walking action depicted in a sound sample. Second, participants listened to 2 different sound samples and discriminated differences in SL. In a 2nd experiment, these procedures were repeated using synthesized sounds derived from the kinetic interactions between the foot and walking surface. A 3rd experiment examined the influence of altered cadence on participants' ability to discriminate changes in SL. Participants significantly adapted their own SL and cadence according to those depicted in both real and synthesized sounds (p < .01). However, although participants accurately discriminated between large changes in SL, these perceptions were heavily influenced by temporal factors, that is, when cadence changed between samples. These findings show that spatial attributes of action sounds can be both mimicked and discriminated, even when only basic kinetic interactions present within the action are specified.

  16. Remote temperature profiling in the troposphere and stratosphere by the radio-acoustic sounding technique

    NASA Technical Reports Server (NTRS)

    Matuura, N.; Masuda, Y.; Inuki, H.

    1986-01-01

    Radar application of the radio-acoustic sounding technique uses the Doppler frequency shift of radar echoes returning from the atmospheric wave structure, in association with a traveling acoustic pulse transmitted from the ground, to determine the speed of sound, and hence the atmospheric temperature, as a function of altitude. Temperature measurement in the troposphere and stratosphere were determined using the radio-acoustic sounding technique with the Radio-Acoustic Sounding System (RASS). Successful experiments were performed in March 1985, and in August 1985.

  17. Radiation of Sound Waves Via Soliton Excitation of the Angarmonic Chain of Atoms in a Dislocation Core

    NASA Astrophysics Data System (ADS)

    Gestrin, S. G.; Shchukina, E. V.

    2016-07-01

    It is demonstrated that propagation of the soliton described by the Boussinesq equation along a linear defect of the crystal structure leads to radiation of sound waves (analog of the Vavilov-Cherenkov effect). Radiation that has a continuous spectrum diverges conically from the dislocation line, and the apex angle of the cone is determined by the ratio of the sound speed in the crystal to the soliton speed. With increasing soliton speed, the maximum of the spectral flux density of sound energy is displaced toward higher frequencies. An analytical expression for energy losses is derived.

  18. 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.

  19. Acoustic wavepackets and sound radiation by jets

    NASA Astrophysics Data System (ADS)

    Sasidharan Nair, Unnikrishnan; Gaitonde, Datta

    2016-11-01

    The three-dimensional spatio-temporal evolution of the acoustic mode in a supersonic jet is analyzed using Doak's Momentum Potential Theory on an LES database. The acoustic mode exhibits a well-defined wavepacket nature in the core and convects at sonic speed. Its spatial coherence is significantly higher than the hydrodynamic component, resulting in an efficient sound radiation mechanism dominated by the axisymmetric and the first helical modes. Enthalpy transport by the acoustic mode yields insight into the sound energy flux emitted by the jet. Intrusion and ejection of coherent vortices into the core and ambient outer fluid respectively are found to be major intermittent sources of acoustic radiation. The scalar potential which defines the acoustic mode is found to satisfy the homogenous wave propagation equation in the nearfield which makes it a suitable variable to predict farfield radiation. The propagated acoustic field closely resembles the corresponding nearfield LES result. The acoustic mode thus provides a physically consistent wavepacket model to predict sound radiation from jets. Ongoing efforts on subsonic jets will discern the influence, if any, of the Mach number on the model.

  20. Underwater tunable organ-pipe sound source.

    PubMed

    Morozov, Andrey K; Webb, Douglas C

    2007-08-01

    A highly efficient frequency-controlled sound source based on a tunable high-Q underwater acoustic resonator is described. The required spectrum width was achieved by transmitting a linear frequency-modulated signal and simultaneously tuning the resonance frequency, keeping the sound source in resonance at the instantaneous frequency of the signal transmitted. Such sound sources have applications in ocean-acoustic tomography and deep-penetration seismic tomography. Mathematical analysis and numerical simulation show the Helmholtz resonator's ability for instant resonant frequency switching and quick adjustment of its resonant frequency to the instantaneous frequency signal. The concept of a quick frequency adjustment filter is considered. The discussion includes the simplest lumped resonant source as well as the complicated distributed system of a tunable organ pipe. A numerical model of the tunable organ pipe is shown to have a form similar to a transmission line segment. This provides a general form for the principal results, which can be applied to tunable resonators of a different physical nature. The numerical simulation shows that the "state-switched" concept also works in the high-Q tunable organ pipe, and the speed of frequency sweeping in a high-Q tunable organ pipe is analyzed. The simulation results were applied to a projector design for ocean-acoustic tomography.

  1. Speed, Acceleration, and Velocity: Level II, Unit 9, Lesson 1; Force, Mass, and Distance: Lesson 2; Types of Motion and Rest: Lesson 3; Electricity and Magnetism: Lesson 4; Electrical, Magnetic, and Gravitational Fields: Lesson 5; The Conservation and Conversion of Matter and Energy: Lesson 6; Simple Machines and Work: Lesson 7; Gas Laws: Lesson 8; Principles of Heat Engines: Lesson 9; Sound and Sound Waves: Lesson 10; Light Waves and Particles: Lesson 11; Program. A High.....

    ERIC Educational Resources Information Center

    Manpower Administration (DOL), Washington, DC. Job Corps.

    This self-study program for high-school level contains lessons on: Speed, Acceleration, and Velocity; Force, Mass, and Distance; Types of Motion and Rest; Electricity and Magnetism; Electrical, Magnetic, and Gravitational Fields; The Conservation and Conversion of Matter and Energy; Simple Machines and Work; Gas Laws; Principles of Heat Engines;…

  2. 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'.

  3. A new method for speed estimation of magnetically suspended flywheel in low speed region

    NASA Astrophysics Data System (ADS)

    Liu, Gang; Liu, Jianzhang; Li, Jianke

    2008-10-01

    It is very important to accurately detect rotor position and speed in brushless direct current motor (BLDCM). Aiming at BLDCM which drives the magnetic suspended reaction flywheel (MSRFW), a novel scheme to estimate the low speed of the BLDCM based on Hall sensors and Kalmam fliter is presented. The average speed over the previous sector is achieved according to the outputs of the three hall sensors, then rotor position of the next sector is computed at the sampling time. The electrical angle calculated can be used to estimate the transient speed with Kalman filter equation. Simulation and experiment show that the proposed method is valid.

  4. Coupled-mode sound propagation in a range-dependent, moving fluid

    NASA Astrophysics Data System (ADS)

    Godin, Oleg A.

    2002-05-01

    Full-field acoustic methods for current velocity inversion require accurate and efficient mathematical models of sound propagation in a range-dependent waveguide with flow. In this paper, an exact coupled-mode representation of the acoustic field is derived. To account for the physics of the problem, normal modes in a corresponding range-independent waveguide are chosen as the local basis. In the absence of currents, mode shape functions form a complete orthogonal basis. This property is heavily used in coupled-mode theories of sound propagation in motionless fluid. Unlike in the motionless case, however, vertical dependencies of acoustic pressure in individual normal modes are not orthogonal in the presence of currents. To overcome this difficulty, linearized equations of hydrodynamics are rewritten in terms of a state vector. Its five components are expressed in terms of acoustic pressure and particle displacement due to the wave. Orthogonality of the state vectors corresponding to individual normal modes is established. Coupled differential equations are derived for range-dependent mode amplitudes, leading to a remarkably simple result. The mode-coupling equations have the same form as those known for the motionless case, but of course the values of the mode-coupling coefficients differ as long as the range dependence of the flow velocity contributes to mode coupling in addition to the range dependence of sound speed and fluid density. The mode-coupling formulation is verified against known coupled-mode equations for certain limiting cases and an exact analytic solution of a benchmark problem.

  5. 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

  6. Visualization of the hot chocolate sound effect by spectrograms

    NASA Astrophysics Data System (ADS)

    Trávníček, Z.; Fedorchenko, A. I.; Pavelka, M.; Hrubý, J.

    2012-12-01

    We present an experimental and a theoretical analysis of the hot chocolate effect. The sound effect is evaluated using time-frequency signal processing, resulting in a quantitative visualization by spectrograms. This method allows us to capture the whole phenomenon, namely to quantify the dynamics of the rising pitch. A general form of the time dependence volume fraction of the bubbles is proposed. We show that the effect occurs due to the nonlinear dependence of the speed of sound in the gas/liquid mixture on the volume fraction of the bubbles and the nonlinear time dependence of the volume fraction of the bubbles.

  7. Inexpensive Audio Activities: Earbud-based Sound Experiments

    NASA Astrophysics Data System (ADS)

    Allen, Joshua; Boucher, Alex; Meggison, Dean; Hruby, Kate; Vesenka, James

    2016-11-01

    Inexpensive alternatives to a number of classic introductory physics sound laboratories are presented including interference phenomena, resonance conditions, and frequency shifts. These can be created using earbuds, economical supplies such as Giant Pixie Stix® wrappers, and free software available for PCs and mobile devices. We describe two interference laboratories (beat frequency and two-speaker interference) and two resonance laboratories (quarter- and half-wavelength). Lastly, a Doppler laboratory using rotating earbuds is explained. The audio signal captured by all experiments is analyzed on free spectral analysis software and many of the experiments incorporate the unifying theme of measuring the speed of sound in air.

  8. 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.

  9. Does a pneumotach accurately characterize voice function?

    NASA Astrophysics Data System (ADS)

    Walters, Gage; Krane, Michael

    2016-11-01

    A study is presented which addresses how a pneumotach might adversely affect clinical measurements of voice function. A pneumotach is a device, typically a mask, worn over the mouth, in order to measure time-varying glottal volume flow. By measuring the time-varying difference in pressure across a known aerodynamic resistance element in the mask, the glottal volume flow waveform is estimated. Because it adds aerodynamic resistance to the vocal system, there is some concern that using a pneumotach may not accurately portray the behavior of the voice. To test this hypothesis, experiments were performed in a simplified airway model with the principal dimensions of an adult human upper airway. A compliant constriction, fabricated from silicone rubber, modeled the vocal folds. Variations of transglottal pressure, time-averaged volume flow, model vocal fold vibration amplitude, and radiated sound with subglottal pressure were performed, with and without the pneumotach in place, and differences noted. Acknowledge support of NIH Grant 2R01DC005642-10A1.

  10. Space Shuttle Crawler Transporter Sound Attenuation Study

    NASA Technical Reports Server (NTRS)

    Margasahayam, Ravi N.; MacDonald, Rod; Faszer, Clifford

    2004-01-01

    The crawler transporter (CT) is the world's largest tracked vehicle known, weighing 6 million pounds with a length of 131 feet and a width of 113 feet. The Kennedy Space Center (KSC) has two CTs that were designed and built for the Apollo program in the 1960's, maintained and retrofitted for use in the Space Shuttle program. As a key element of the Space Shuttle ground systems, the crawler transports the entire 12-million-pound stack comprising the orbiter, the mobile launch platform (MLP), the external tank (ET), and the solid rocket boosters (SRB) from the Vehicle Assembly Building (VAB) to the launch pad. This rollout, constituting a 3.5-5.0-mile journey at a top speed of 0.9 miles-per-hour, requires over 8 hours to reach either Launch Complex 39A or B. This activity is only a prelude to the spectacle of sound and fury of the Space Shuttle launch to orbit in less than 10 minutes and traveling at orbital velocities of Mach 24. This paper summarizes preliminary results from the Crawler Transporter Sound Attenuation Study, encompassing test and engineering analysis of significant sound sources to measure and record full frequency spectrum and intensity of the various noise sources and to analyze the conditions of vibration. Additionally, data such as ventilation criteria, plus operational procedures were considered to provide a comprehensive noise suppression design for implementation. To date, sound attenuation study and results on Crawler 2 have shown significant noise reductions ranging from 5 to 24 dBA.

  11. Binaural sound localization using neural networks

    NASA Astrophysics Data System (ADS)

    Craig, Rushby C.

    1991-12-01

    The purpose of this study was to investigate the use of Artificial Neural Networks to localize sound sources from simulated, human binaural signals. Only sound sources originating from a circle on the horizontal plane were considered. Experiments were performed to examine the ability of the networks to localize using three-different feature sets. The feature sets used were: time-samples of the signals, Fast Fourier Transform magnitude and cross correlation data, and auto-correlation and cross correlation data. The two different types of sound source signals considered were tones and gaussian noise. The feature set which yielded the best results in terms of classification accuracy (over 91 percent) for both tones and noise was the auto-correlation and cross-correlation data. These results were achieved using 18 classes (20 per class). The other two feature sets did not produce accuracy results as high or as consistent between the two signal types. When using time-samples of the signals as features, it was observed that in order to accurately classify tones of random-frequency, it was necessary to train with random-frequency tones rather than with tones of one, or a few discrete frequencies.

  12. Real-time control of sound diffusion parameters

    NASA Astrophysics Data System (ADS)

    Leider, Colby

    2003-04-01

    Much electronic and computer music relies extensively on real-time diffusion of electronic sound in surround loudspeaker configurations. The most common method of sound diffusion in practice today is to use standard sound-reinforcement mixers whereby each fader controls the playback volume of a corresponding loudspeaker in a concert hall. Using the mixer this way, however, presents problems when one attempts to create sound trajectories, because complex, precise, and repeatable control of the individual faders is required. To address these interface issues, two different handheld controllers were created for real-time sound diffusion. The first controller is equipped accelerometers, force-sensing resistors, and joysticks and maps using input into diffusion parameters. The second controller mimics the operation of a standard mixer but allows more rapid movement of fader positions by replacing each fader with a bend sensor. To test the validity of each controller, twenty undergraduate music engineering students were asked to repeatedly perform various diffusion tasks (such as moving a monaural sound in a circle around the audience) using a standard mixer and each of the controllers. The accuracy and speed of their performances were tracked. The study concludes with lessons learned from the statistics gathered. [Research supported by the University of Miami.

  13. Aircraft Speed Instruments

    NASA Technical Reports Server (NTRS)

    Beij, K Hilding

    1933-01-01

    This report presents a concise survey of the measurement of air speed and ground speed on board aircraft. Special attention is paid to the pitot-static air-speed meter which is the standard in the United States for airplanes. Air-speed meters of the rotating vane type are also discussed in considerable detail on account of their value as flight test instruments and as service instruments for airships. Methods of ground-speed measurement are treated briefly, with reference to the more important instruments. A bibliography on air-speed measurement concludes the report.

  14. A Simple Experiment to Explore Standing Waves in a Flexible Corrugated Sound Tube

    NASA Astrophysics Data System (ADS)

    Amorim, Maria Eva; Sousa, Teresa Delmira; Carvalho, P. Simeão; Sousa, Adriano Sampaioe

    2011-09-01

    Sound tubes, pipes, and singing rods are used as musical instruments and as toys to perform amusing experiments. In particular, corrugated tubes present unique characteristics with respect to the sounds they can produce; that is why they have been studied so intensively, both at theoretical and experimental levels.1-4 Experimental studies usually involve expensive and sophisticated equipment that is out of reach of school laboratory facilities.3-6 In this paper we show how to investigate quantitatively the sounds produced by a flexible sound tube corrugated on the inside by using educational equipment readily available in school laboratories, such as the oscilloscope, the microphone, the anemometer, and the air pump. We show that it is possible for students to study the discontinuous spectrum of sounds produced by a flexible corrugated tube and go even further, computing the speed of sound in air with a simple experimental procedure.

  15. 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

  16. An experimental device for accurate ultrasounds measurements in liquid foods at high pressure

    NASA Astrophysics Data System (ADS)

    Hidalgo-Baltasar, E.; Taravillo, M.; Baonza, V. G.; Sanz, P. D.; Guignon, B.

    2012-12-01

    The use of high hydrostatic pressure to ensure safe and high-quality product has markedly increased in the food industry during the last decade. Ultrasonic sensors can be employed to control such processes in an equivalent way as they are currently used in processes carried out at room pressure. However, their installation, calibration and use are particularly challenging in the context of a high pressure environment. Besides, data about acoustic properties of food under pressure and even for water are quite scarce in the pressure range of interest for food treatment (namely, above 200 MPa). The objective of this work was to establish a methodology to determine the speed of sound in foods under pressure. An ultrasonic sensor using the multiple reflections method was adapted to a lab-scale HHP equipment to determine the speed of sound in water between 253.15 and 348.15 K, and at pressures up to 700 MPa. The experimental speed-of-sound data were compared to the data calculated from the equation of state of water (IAPWS-95 formulation). From this analysis, the way to calibrate cell path was validated. After this calibration procedure, the speed of sound could be determined in liquid foods by using this sensor with a relative uncertainty between (0.22 and 0.32) % at a confidence level of 95 % over the whole pressure domain.

  17. Economy of flight at supersonic speeds

    NASA Technical Reports Server (NTRS)

    Jones, R. T.

    1976-01-01

    Prandtl's theory is used to determine the airflow over bodies and wings adapted to supersonic flight. By making use of these results, and by incorporating in them an allowance for the probable skin friction, some estimates of expected lift-drag ratios are made for various flight speeds with the best configuration. At each speed a slender body and wings having the best angle of sweepback are considered. For the range of supersonic speeds shown an airplane of normal density and loading would be required to operate at an altitude of the order of 60,000 feet. The limiting value of 1-1/2 times the speed of sound corresponds to a flight speed of 1000 miles per hour. At this speed about 1.5 miles per gallon of fuel are expected. It is interesting to note that this value corresponds to a value of more than 15 miles per gallon when the weight is reduced to correspond to that of an ordinary automobile.

  18. 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.

  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. 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.

  1. 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

  2. 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

  3. 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

  4. High speed flow past wings

    NASA Technical Reports Server (NTRS)

    Norstrud, H.

    1973-01-01

    The analytical solution to the transonic small perturbation equation which describes steady compressible flow past finite wings at subsonic speeds can be expressed as a nonlinear integral equation with the perturbation velocity potential as the unknown function. This known formulation is substituted by a system of nonlinear algebraic equations to which various methods are applicable for its solution. Due to the presence of mathematical discontinuities in the flow solutions, however, a main computational difficulty was to ensure uniqueness of the solutions when local velocities on the wing exceeded the speed of sound. For continuous solutions this was achieved by embedding the algebraic system in an one-parameter operator homotopy in order to apply the method of parametric differentiation. The solution to the initial system of equations appears then as a solution to a Cauchy problem where the initial condition is related to the accompanying incompressible flow solution. In using this technique, however, a continuous dependence of the solution development on the initial data is lost when the solution reaches the minimum bifurcation point. A steepest descent iteration technique was therefore, added to the computational scheme for the calculation of discontinuous flow solutions. Results for purely subsonic flows and supersonic flows with and without compression shocks are given and compared with other available theoretical solutions.

  5. Vehicle speed control device

    SciTech Connect

    Thornton-Trump, W.E.

    1987-03-10

    An apparatus is described for automatically limiting the speed of a vehicle powered by an internal combustion engine having a spark ignition system with an ignition coil, comprising: sensor means for generating a speed signal directly representative of the speed of the vehicle comprising a series of speed signal pulses having a pulse repetition frequency proportional to the speed of the vehicle; control means for converting speed signal pulses into a DC voltage proportional to the vehicle speed; means for comparing the DC voltage to a predetermined DC voltage having substantially zero AC components representative of a predetermined maximum speed and for generating a difference signal in response thereto; and means for generating a pulse-width modulated control signal responsive to the difference signal; power means responsive to the control signal for intermittently interrupting the ignition system.

  6. System and method for characterizing, synthesizing, and/or canceling out acoustic signals from inanimate sound sources

    DOEpatents

    Holzrichter, John F.; Burnett, Greg C.; Ng, Lawrence C.

    2007-10-16

    A system and method for characterizing, synthesizing, and/or canceling out acoustic signals from inanimate sound sources is disclosed. Propagating wave electromagnetic sensors monitor excitation sources in sound producing systems, such as machines, musical instruments, and various other structures. Acoustical output from these sound producing systems is also monitored. From such information, a transfer function characterizing the sound producing system is generated. From the transfer function, acoustical output from the sound producing system may be synthesized or canceled. The methods disclosed enable accurate calculation of matched transfer functions relating specific excitations to specific acoustical outputs. Knowledge of such signals and functions can be used to effect various sound replication, sound source identification, and sound cancellation applications.

  7. System and method for characterizing, synthesizing, and/or canceling out acoustic signals from inanimate sound sources

    SciTech Connect

    Holzrichter, John F; Burnett, Greg C; Ng, Lawrence C

    2013-05-21

    A system and method for characterizing, synthesizing, and/or canceling out acoustic signals from inanimate sound sources is disclosed. Propagating wave electromagnetic sensors monitor excitation sources in sound producing systems, such as machines, musical instruments, and various other structures. Acoustical output from these sound producing systems is also monitored. From such information, a transfer function characterizing the sound producing system is generated. From the transfer function, acoustical output from the sound producing system may be synthesized or canceled. The methods disclosed enable accurate calculation of matched transfer functions relating specific excitations to specific acoustical outputs. Knowledge of such signals and functions can be used to effect various sound replication, sound source identification, and sound cancellation applications.

  8. System and method for characterizing synthesizing and/or canceling out acoustic signals from inanimate sound sources

    DOEpatents

    Holzrichter, John F.; Burnett, Greg C.; Ng, Lawrence C.

    2003-01-01

    A system and method for characterizing, synthesizing, and/or canceling out acoustic signals from inanimate sound sources is disclosed. Propagating wave electromagnetic sensors monitor excitation sources in sound producing systems, such as machines, musical instruments, and various other structures. Acoustical output from these sound producing systems is also monitored. From such information, a transfer function characterizing the sound producing system is generated. From the transfer function, acoustical output from the sound producing system may be synthesized or canceled. The methods disclosed enable accurate calculation of matched transfer functions relating specific excitations to specific acoustical outputs. Knowledge of such signals and functions can be used to effect various sound replication, sound source identification, and sound cancellation applications.

  9. Speed-sensing device aids crane operators

    NASA Technical Reports Server (NTRS)

    1964-01-01

    So that crane operators can judge payload movements accurately, a friction-driven multilobed cam device energizes a buzzer and indicator lamp in the crane cab. The signal frequency of this speed sensor has a sensitivity to hoist movement of 1/8 inch.

  10. Accurate upwind-monotone (nonoscillatory) methods for conservation laws

    NASA Technical Reports Server (NTRS)

    Huynh, Hung T.

    1992-01-01

    The well known MUSCL scheme of Van Leer is constructed using a piecewise linear approximation. The MUSCL scheme is second order accurate at the smooth part of the solution except at extrema where the accuracy degenerates to first order due to the monotonicity constraint. To construct accurate schemes which are free from oscillations, the author introduces the concept of upwind monotonicity. Several classes of schemes, which are upwind monotone and of uniform second or third order accuracy are then presented. Results for advection with constant speed are shown. It is also shown that the new scheme compares favorably with state of the art methods.

  11. Speed limits of aircraft

    NASA Technical Reports Server (NTRS)

    Everling, E

    1923-01-01

    This paper is restricted to the question of attainable speed limits and attacks the problem from different angles. Theoretical limits due to air resistance are presented along with design factors which may affect speed such as wing loads, wing areas, wing section shifting, landing speeds, drag-lift ratios, and power coefficients.

  12. Differentiating speech and nonspeech sounds via amplitude envelope cues

    NASA Astrophysics Data System (ADS)

    Lehnhoff, Robert J.; Strange, Winifred; Long, Glenis

    2001-05-01

    Recent evidence from neuroscience and behavioral speech science suggests that the temporal modulation pattern of the speech signal plays a distinctive role in speech perception. As a first step in exploring the nature of the perceptually relevant information in the temporal pattern of speech, this experiment examined whether speech versus nonspeech environmental sounds could be differentiated on the basis of their amplitude envelopes. Conversational speech was recorded from native speakers of six different languages (French, German, Hebrew, Hindi, Japanese, and Russian) along with samples of their English. Nonspeech sounds included animal vocalizations, water sounds, and other environmental sounds (e.g., thunder). The stimulus set included 30 2-s speech segments and 30 2-s nonspeech events. Frequency information was removed from all stimuli using a technique described by Dorman et al. [J. Acoust. Soc. Am. 102 (1997)]. Nine normal-hearing adult listeners participated in the experiment. Subjects decided whether each sound was (originally) speech or nonspeech and rated their confidence (7-point Likert scale). Overall, subjects differentiated speech from nonspeech very accurately (84% correct). Only 12 stimuli were not correctly categorized at greater than chance levels. Acoustical analysis is underway to determine what parameters of the amplitude envelope differentiate speech from nonspeech sounds.

  13. Differentiating speech and nonspeech sounds via amplitude envelope cues

    NASA Astrophysics Data System (ADS)

    Lehnhoff, Robert J.; Strange, Winifred; Long, Glenis

    2004-05-01

    Recent evidence from neuroscience and behavioral speech science suggests that the temporal modulation pattern of the speech signal plays a distinctive role in speech perception. As a first step in exploring the nature of the perceptually relevant information in the temporal pattern of speech, this experiment examined whether speech versus nonspeech environmental sounds could be differentiated on the basis of their amplitude envelopes. Conversational speech was recorded from native speakers of six different languages (French, German, Hebrew, Hindi, Japanese, and Russian) along with samples of their English. Nonspeech sounds included animal vocalizations, water sounds, and other environmental sounds (e.g., thunder). The stimulus set included 30 2-s speech segments and 30 2-s nonspeech events. Frequency information was removed from all stimuli using a technique described by Dorman et al. [J. Acoust. Soc. Am. 102 (1997)]. Nine normal-hearing adult listeners participated in the experiment. Subjects decided whether each sound was (originally) speech or nonspeech and rated their confidence (7-point Likert scale). Overall, subjects differentiated speech from nonspeech very accurately (84% correct). Only 12 stimuli were not correctly categorized at greater than chance levels. Acoustical analysis is underway to determine what parameters of the amplitude envelope differentiate speech from nonspeech sounds.

  14. The 1980 land cover for the Puget Sound region

    NASA Technical Reports Server (NTRS)

    Shinn, R. D.; Westerlund, F. V.; Eby, J. R.

    1982-01-01

    Both LANDSAT imagery and the video information communications and retrieval software were used to develop a land cover classifiction of the Puget Sound of Washington. Planning agencies within the region were provided with a highly accurate land cover map registered to the 1980 census tracts which could subsequently be incorporated as one data layer in a multi-layer data base. Many historical activities related to previous land cover mapping studies conducted in the Puget Sound region are summarized. Valuable insight into conducting a project with a large community of users and in establishing user confidence in a multi-purpose land cover map derived from LANDSAT is provided.

  15. 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.

  16. The NASA-LeRC wind turbine sound prediction code

    NASA Technical Reports Server (NTRS)

    Viterna, L. A.

    1981-01-01

    Since regular operation of the DOE/NASA MOD-1 wind turbine began in October 1979 about 10 nearby households have complained of noise from the machine. Development of the NASA-LeRC with turbine sound prediction code began in May 1980 as part of an effort to understand and reduce the noise generated by MOD-1. Tone sound levels predicted with this code are in generally good agreement with measured data taken in the vicinity MOD-1 wind turbine (less than 2 rotor diameters). Comparison in the far field indicates that propagation effects due to terrain and atmospheric conditions may be amplifying the actual sound levels by about 6 dB. Parametric analysis using the code has shown that the predominant contributions to MOD-1 rotor noise are: (1) the velocity deficit in the wake of the support tower; (2) the high rotor speed; and (3) off column operation.

  17. The NASA-LeRC wind turbine sound prediction code

    NASA Technical Reports Server (NTRS)

    Viterna, L. A.

    1981-01-01

    Development of the wind turbine sound prediction code began as part of an effort understand and reduce the noise generated by Mod-1. Tone sound levels predicted with this code are in good agreement with measured data taken in the vicinity Mod-1 wind turbine (less than 2 rotor diameters). Comparison in the far field indicates that propagation effects due to terrain and atmospheric conditions may amplify the actual sound levels by 6 dB. Parametric analysis using the code shows that the predominant contributors to Mod-1 rotor noise are (1) the velocity deficit in the wake of the support tower, (2) the high rotor speed, and (3) off-optimum operation.

  18. Sound transmission through a fluctuating ocean: A modal approach

    NASA Astrophysics Data System (ADS)

    Udovydchenkov, Ilya A.

    Sound transmission through a fluctuating deep ocean environment is considered. It is assumed that the environment consists of a range-independent background, on which a small-scale perturbation, due for example to internal waves, is superimposed. The modal description of underwater sound propagation is used extensively. The temporal spread of modal group arrivals in weakly range-dependent deep ocean environments is considered. The phrase "modal group arrival" refers to the contribution to a transient wavefield corresponding to a fixed mode number. It is shown that there are three contributions to modal group time spreads which combine approximately in quadrature. These are the reciprocal bandwidth, a deterministic dispersive contribution, and a scattering-induced contribution. The latter two contributions are shown to be proportional to the waveguide invariant beta, a property of the background sound speed profile. The results presented are based mostly on asymptotic theory. Sonic extensions of the asymptotic modal theory are developed. These theoretical results are shown to agree well with full-wave numerical wavefield simulations and available exact mode theoretical results. Theoretical predictions of modal group time spreads are compared to estimates derived from data that was collected during the 2004 LOAPEX experiment. The effects of deficiencies in the receiving array on estimates of modal group time spreads are discussed. It is shown that in spite of array deficiencies in the LOAPEX measurements it is possible to estimate modal group time spreads for almost all propagating modes and these estimates agree well with results obtained from numerical simulations and the developed theory. The effect of ocean internal waves on sound speed fluctuations is also considered, motivated by the observation that the amount of energy being scattered along the propagation path is sometimes greater in the experimental data than predicted by numerical simulations and theory

  19. 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.

  20. 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.

  1. 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.

  2. 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…

  3. 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…

  4. 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…

  5. Gaseous Absorption and Dispersion of Sound in a Resonant Cylindrical Cavity: AN Acoustic and Photoacoustic Study

    NASA Astrophysics Data System (ADS)

    Beckwith, Clyfe Gordon

    This research investigated the feasibility of accurately measuring Virial coefficients in an acoustically resonant cylindrical cavity. Gases studied were: Argon, Helium, Nitrogen, Carbon Dioxide, and Methane. Parameters considered were: resonant frequencies (f_ {rm r}- also a measure of speed of sound), quality factors (Q), and signal amplitudes. We studied the longitudinal modes smaller than 2000 Hz, at room temperature and at pressures of 200, 500, and 800 mm of Hg. The choice of the longitudinal modes was predetermined by our wish to compare acoustic and photoacoustic resonance techniques of the same mode. The acoustic excitation is limited to the longitudinal modes and is achieved by placing a loudspeaker close to one end of the cavity. Photoacoustically we excite a small concentration of molecular Iodine, mixed in with the buffer gases, by a periodically interrupted Xenon light beam. By increasing the length of the cavity we could decrease the space between the modes of frequency. Our observations focused on the behaviors that (a) f_{rm r} shifted with pressure, (b) the f_{rm r} deviated from the simple laws of harmonics, and (c) the amplitudes for the two techniques varied differently with frequency. Effect (a) is due to the fact that the gases are not "ideal", and due to the presence of boundary layers caused by thermal conduction and viscosity gradients. Effect (b) arises because of the f_{rm r}'s mode dependence, caused by the wave scattering due to imperfect geometrical symmetries. Effect (c) is governed by the coupling factors. All measurements could theoretically be justified to within instrumental error, the only noted discrepancy is the lack of a theoretical mode dependence. We conclude that it is feasible to study the accuracy of Virial coefficients of simple gases provided that the boundary layer loss effects and the mode dependent wave scattering can be quantified; in regions of high pressures and high frequencies the Virial effects dominate the

  6. CFD and transonic helicopter sound

    NASA Technical Reports Server (NTRS)

    Purcell, Timothy W.

    1988-01-01

    A computational method which predicts far-field impulsive noise from a transonic motor blade is demonstrated. This method couples near-field results from a full-potential finite-difference method with a new Kirchhoff integral formulation to extend the finite-difference results into the acoustic far-field. This Kirchhoff formula is written in a blade-fixed coordinate system. It requires initial data from the potential code on a plane at the sonic radius. A recent hovering rotor experiment is described where accurate pressure measurements were recorded on the sonic cylinder and at 2 and 3 radii. The potential code prediction of sonic cylinder pressures is excellent. Acoustic far-field pressure predictions show good agreement with hover experimental data over the range of speeds from 0.85 to 0.92 tip Mach number, the latter of which have delocalized transonic flow. These results are some of the first successful predictions for peak pressure amplitudes using a computational code.

  7. 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.

  8. Sound Level Measurements

    DTIC Science & Technology

    2011-08-01

    2.2.2.2 Transducer Applications. a. For measurements above 40 kPa (186 dB), pointed or disc -shaped piezoelectric or piezoresistive probes with...speed increments from slow to maximum. TOP 01-2-608A 1 August 2011 12 (3) Record dBA, and an octave-band analysis at each microphone...compartment and record the dBA and octave-band analysis for the condition-of-vessel operation that produces the most noise. (4) When cargo

  9. 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.

  10. I Am the Speed of Light "c", You "See"...!

    ERIC Educational Resources Information Center

    Shivalingaswamy, T.; Rashmi, P. E.

    2014-01-01

    The accurate measurement of speed of light is of great importance in understanding various concepts in Physics in particular and science in general. In Physics we come across various concepts and applications in which high degree of accuracy of speed of light becomes important. In this article we discuss the various attempts made to determine the…

  11. 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 ...

  12. Sound propagation and absorption in foam - A distributed parameter model.

    NASA Technical Reports Server (NTRS)

    Manson, L.; Lieberman, S.

    1971-01-01

    Liquid-base foams are highly effective sound absorbers. A better understanding of the mechanisms of sound absorption in foams was sought by exploration of a mathematical model of bubble pulsation and coupling and the development of a distributed-parameter mechanical analog. A solution by electric-circuit analogy was thus obtained and transmission-line theory was used to relate the physical properties of the foams to the characteristic impedance and propagation constants of the analog transmission line. Comparison of measured physical properties of the foam with values obtained from measured acoustic impedance and propagation constants and the transmission-line theory showed good agreement. We may therefore conclude that the sound propagation and absorption mechanisms in foam are accurately described by the resonant response of individual bubbles coupled to neighboring bubbles.

  13. Monaural sound localization based on structure-induced acoustic resonance.

    PubMed

    Kim, Keonwook; Kim, Youngwoong

    2015-02-06

    A physical structure such as a cylindrical pipe controls the propagated sound spectrum in a predictable way that can be used to localize the sound source. This paper designs a monaural sound localization system based on multiple pyramidal horns around a single microphone. The acoustic resonance within the horn provides a periodicity in the spectral domain known as the fundamental frequency which is inversely proportional to the radial horn length. Once the system accurately estimates the fundamental frequency, the horn length and corresponding angle can be derived by the relationship. The modified Cepstrum algorithm is employed to evaluate the fundamental frequency. In an anechoic chamber, localization experiments over azimuthal configuration show that up to 61% of the proper signal is recognized correctly with 30% misfire. With a speculated detection threshold, the system estimates direction 52% in positive-to-positive and 34% in negative-to-positive decision rate, on average.

  14. Wearable Eating Habit Sensing System Using Internal Body Sound

    NASA Astrophysics Data System (ADS)

    Shuzo, Masaki; Komori, Shintaro; Takashima, Tomoko; Lopez, Guillaume; Tatsuta, Seiji; Yanagimoto, Shintaro; Warisawa, Shin'ichi; Delaunay, Jean-Jacques; Yamada, Ichiro

    Continuous monitoring of eating habits could be useful in preventing lifestyle diseases such as metabolic syndrome. Conventional methods consist of self-reporting and calculating mastication frequency based on the myoelectric potential of the masseter muscle. Both these methods are significant burdens for the user. We developed a non-invasive, wearable sensing system that can record eating habits over a long period of time in daily life. Our sensing system is composed of two bone conduction microphones placed in the ears that send internal body sound data to a portable IC recorder. Applying frequency spectrum analysis on the collected sound data, we could not only count the number of mastications during eating, but also accurately differentiate between eating, drinking, and speaking activities. This information can be used to evaluate the regularity of meals. Moreover, we were able to analyze sound features to classify the types of foods eaten by food texture.

  15. 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.

  16. Sound scattering in shallow water in presence of internal solitons

    NASA Astrophysics Data System (ADS)

    Katsnelson, Boris G.; Pereselkov, Serguey A.; Petnikov, Valery G.

    2002-05-01

    Sound scattering by localized inhomogeneity (object) in a shallow-water waveguide is studied. Influence of internal solitons (IS) traveling in the sea, on the scattered field is considered. The problem is analyzed within the framework of theory of the sound scattering in the waveguide developed by the authors, where the scattering matrix is expressed through modal decomposition including the scattering amplitude of the object in free space. The peculiarity of the given work is the taking into account of additional modes conversion due to IS. The waveguide and IS are modeled on the basis of experimental data (sound-speed profile, bottom relief, IS parameters, etc.) collected in the Japan Sea. The inhomogeneity is selected in the form of soft spheroids with dimensions characteristic of gray whales (eschrichtius). Calculations of amplitude fluctuations of the low-frequency sound field at the receiving point are carried out for moving spheroid and different orientations of acoustic track with respect to direction of propagation of IS. It is shown that sound fluctuations have essentially different characteristics for longitudinal and transversal propagation of IS. [Work supported by RFBR, Grant No. 00-05-64752.

  17. STS-57 Earth observation of King Sound in northwest Australia

    NASA Technical Reports Server (NTRS)

    1993-01-01

    STS-57 Earth observation taken aboard Endeavour, Orbiter Vehicle (OV) 105, is of King Sound in northwest Australia. Roebuck Bay with the city of Broom on its northern shore is south of King Sound. Sediment in the sound is deposited by the Fitzroy River, which is the major body draining the Kimberley Plateau about 200 miles to the west. The extent of the tidal flats around the Sound is indicated by the large white areas covered with a salty residue. According to NASA scientists studying the STS-57 Earth photos, northwest wind gusts are ruffling areas of the water's surface at the mouth of King Sound and in neighboring Collier Bay. Therefore the water is less reflective and dark. The higher reflectance on the brightest areas is caused by biological oils floating on the surface and reducing the capillary wave action. The scientists point out that the oils take the forms of the currents and eddies in the picture. These eddies indicate that the water offshore is moving at a different speed

  18. A model problem for sound radiation by an installed jet

    NASA Astrophysics Data System (ADS)

    Nogueira, Petrônio A. S.; Cavalieri, André V. G.; Jordan, Peter

    2017-03-01

    A model for sound generation by a jet in the vicinity of a flat plate, mimicking an exhaust jet installed near an aircraft wing, is presented. An earlier model (Cavalieri et al. J. Sound Vib. 333 (2014) 6516-6531) is further simplified by considering that the sound source is an axially-extended, cylindrical wavepacket concentrated on the jet lipline, and that this source is scattered by the trailing edge of a semi-infinite flat plate; the model is shown to match earlier results and considerably simplifies the analysis. It is used to evaluate how the parameters of the problem influence sound radiation by subsonic jets. We show that the axisymmetric mode of the source is the most acoustically efficient, similarly to what is seen for free jets; but unlike the latter problem, the sound scattered by the trailing edge is only weakly dependent on the details of the wavepacket envelope and on the two-point coherence of the source, the wavepacket phase speed being the salient feature for installed jet noise. We then use the model to evaluate how geometrical parameters of jet-plate configurations modify the radiated sound. The acoustic radiation is particularly sensitive to the jet-plate distance due to the exponential radial decay of near-field disturbances; the relative axial position of jet and trailing edge is shown to play a comparably minor role. Finally, changes in the angle of attack of the plate and in the sweep angle of the trailing edge considerably modify the radiated sound, leading to significant reductions of the acoustic intensity in some directions. The various properties of installed jet noise are further explored by appealing to the wavenumber transform of the tailored Green's function used to compute the scattered field; insight is thus provided on how jet-wing configurations might be designed so as to reduce installation noise.

  19. Comparison of Drop and Wind-Tunnel Experiments on Bomb Drag at High Subsonic Speeds

    NASA Technical Reports Server (NTRS)

    Gothert, B.

    1948-01-01

    The drag coefficients of bombs at high velocities velocity of fall was 97 percent of the speed of sound) (the highest are determined by drop tests and compared with measurements taken in the DVL high-speed closed wind tunnel and the open jet at AVA - Gottingen.

  20. 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.