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Sample records for sound velocity measurement

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

    DEFF Research Database (Denmark)

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

    2012-01-01

    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......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...

  2. Measurement of sound velocity profiles in fluids for process monitoring

    International Nuclear Information System (INIS)

    Wolf, M; Kühnicke, E; Lenz, M; Bock, M

    2012-01-01

    In ultrasonic measurements, the time of flight to the object interface is often the only information that is analysed. Conventionally it is only possible to determine distances or sound velocities if the other value is known. The current paper deals with a novel method to measure the sound propagation path length and the sound velocity in media with moving scattering particles simultaneously. Since the focal position also depends on sound velocity, it can be used as a second parameter. Via calibration curves it is possible to determine the focal position and sound velocity from the measured time of flight to the focus, which is correlated to the maximum of averaged echo signal amplitude. To move focal position along the acoustic axis, an annular array is used. This allows measuring sound velocity locally resolved without any previous knowledge of the acoustic media and without a reference reflector. In previous publications the functional efficiency of this method was shown for media with constant velocities. In this work the accuracy of these measurements is improved. Furthermore first measurements and simulations are introduced for non-homogeneous media. Therefore an experimental set-up was created to generate a linear temperature gradient, which also causes a gradient of sound velocity.

  3. The velocity of sound

    International Nuclear Information System (INIS)

    Beyer, R.T.

    1985-01-01

    The paper reviews the work carried out on the velocity of sound in liquid alkali metals. The experimental methods to determine the velocity measurements are described. Tables are presented of reported data on the velocity of sound in lithium, sodium, potassium, rubidium and caesium. A formula is given for alkali metals, in which the sound velocity is a function of shear viscosity, atomic mass and atomic volume. (U.K.)

  4. Near-field acoustic holography with sound pressure and particle velocity measurements

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren

    of the particle velocity has notable potential in NAH, and furthermore, combined measurement of sound pressure and particle velocity opens a new range of possibilities that are examined in this study. On this basis, sound field separation methods have been studied, and a new measurement principle based on double...... layer measurements of the particle velocity has been proposed. Also, the relation between near-field and far-field radiation from sound sources has been examined using the concept of the supersonic intensity. The calculation of this quantity has been extended to other holographic methods, and studied...

  5. Velocity of sound measurements in gaseous per-fluorocarbons and their custom mixtures

    CERN Document Server

    Vacek, V; Lindsay, S

    2000-01-01

    An inexpensive sonar instrument was prepared for measurements of sound velocity in two fluorocarbon vapors; per-fluoro-n-propane (C3F8), per-fluoro-n-butane (C4F10), and their custom mixtures. The apparatus, measurement principle and instrument software are described. All sound velocity measurements in per-fluorocarbons were made in the low pressure range between 0.01 and 0.4 MPa, and at temperatures between 253 and 303 K. The purity of the C3F8 and C4F10 samples was checked using gas chromatography. Uncertainties in the speed of sound measurements were better than ± 0.1 %. Comparisons were made with theoretical predictions of sound velocity for the two individual components. The instrument was then used for concentration monitoring of custom C3F8/C4F10 mixtures.

  6. Sound Velocity in Soap Foams

    International Nuclear Information System (INIS)

    Wu Gong-Tao; Lü Yong-Jun; Liu Peng-Fei; Li Yi-Ning; Shi Qing-Fan

    2012-01-01

    The velocity of sound in soap foams at high gas volume fractions is experimentally studied by using the time difference method. It is found that the sound velocities increase with increasing bubble diameter, and asymptotically approach to the value in air when the diameter is larger than 12.5 mm. We propose a simple theoretical model for the sound propagation in a disordered foam. In this model, the attenuation of a sound wave due to the scattering of the bubble wall is equivalently described as the effect of an additional length. This simplicity reasonably reproduces the sound velocity in foams and the predicted results are in good agreement with the experiments. Further measurements indicate that the increase of frequency markedly slows down the sound velocity, whereas the latter does not display a strong dependence on the solution concentration

  7. Melting along the Hugoniot and solid phase transition for Sn via sound velocity measurements

    Science.gov (United States)

    Song, Ping; Cai, Ling-cang; Tao, Tian-jiong; Yuan, Shuai; Chen, Hong; Huang, Jin; Zhao, Xin-wen; Wang, Xue-jun

    2016-11-01

    It is very important to determine the phase boundaries for materials with complex crystalline phase structures to construct their corresponding multi-phase equation of state. By measuring the sound velocity of Sn with different porosities, different shock-induced melting pressures along the solid-liquid phase boundary could be obtained. The incipient shock-induced melting of porous Sn samples with two different porosities occurred at a pressure of about 49.1 GPa for a porosity of 1.01 and 45.6 GPa for a porosity of 1.02, based on measurements of the sound velocity. The incipient shock-induced melting pressure of solid Sn was revised to 58.1 GPa using supplemental measurements of the sound velocity. Trivially, pores in Sn decreased the shock-induced melting pressure. Based on the measured longitudinal sound velocity data, a refined solid phase transition and the Hugoniot temperature-pressure curve's trend are discussed. No bcc phase transition occurs along the Hugoniot for porous Sn; further investigation is required to understand the implications of this finding.

  8. Continuous Sound Velocity Measurements along the Shock Hugoniot Curve of Quartz

    Science.gov (United States)

    Li, Mu; Zhang, Shuai; Zhang, Hongping; Zhang, Gongmu; Wang, Feng; Zhao, Jianheng; Sun, Chengwei; Jeanloz, Raymond

    2018-05-01

    We report continuous measurements of the sound velocity along the principal Hugoniot curve of α quartz between 0.25 and 1.45 TPa, as determined from lateral release waves intersecting the shock front as a function of time in decaying-shock experiments. The measured sound velocities are lower than predicted by prior models, based on the properties of stishovite at densities below ˜7 g /cm3 , but agree with density functional theory molecular dynamics calculations and an empirical wide-regime equation of state presented here. The Grüneisen parameter calculated from the sound velocity decreases from γ ˜1 .3 at 0.25 TPa to 0.66 at 1.45 TPa. In combination with evidence for increased (configurational) specific heat and decreased bulk modulus, the values of γ suggest a high thermal expansion coefficient at ˜0. 25 - 0 .65 TPa , where SiO2 is thought to be a bonded liquid. From our measurements, dissociation of the molecular bonds persists to ˜0. 65 - 1 .0 TPa , consistent with estimates by other methods. At higher densities, the sound velocity is close to predictions from previous models, and the Grüneisen parameter approaches the ideal gas value.

  9. Solid phase stability of molybdenum under compression: Sound velocity measurements and first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiulu [Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, P.O. Box 919-102, 621900 Mianyang, Sichuan (China); Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology, 621010 Mianyang, Sichuan (China); Liu, Zhongli [Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, P.O. Box 919-102, 621900 Mianyang, Sichuan (China); College of Physics and Electric Information, Luoyang Normal University, 471022 Luoyang, Henan (China); Jin, Ke; Xi, Feng; Yu, Yuying; Tan, Ye; Dai, Chengda; Cai, Lingcang [Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, P.O. Box 919-102, 621900 Mianyang, Sichuan (China)

    2015-02-07

    The high-pressure solid phase stability of molybdenum (Mo) has been the center of a long-standing controversy on its high-pressure melting. In this work, experimental and theoretical researches have been conducted to check its solid phase stability under compression. First, we performed sound velocity measurements from 38 to 160 GPa using the two-stage light gas gun and explosive loading in backward- and forward-impact geometries, along with the high-precision velocity interferometry. From the sound velocities, we found no solid-solid phase transition in Mo before shock melting, which does not support the previous solid-solid phase transition conclusion inferred from the sharp drops of the longitudinal sound velocity [Hixson et al., Phys. Rev. Lett. 62, 637 (1989)]. Then, we searched its structures globally using the multi-algorithm collaborative crystal structure prediction technique combined with the density functional theory. By comparing the enthalpies of body centered cubic structure with those of the metastable structures, we found that bcc is the most stable structure in the range of 0–300 GPa. The present theoretical results together with previous ones greatly support our experimental conclusions.

  10. Measurement of the velocity of sound in crystals by pulsed neutron diffraction

    International Nuclear Information System (INIS)

    Willis, B.T.M.; Carlile, C.J.; Ward, R.C.; David, W.I.F.; Johnson, M.W.

    1986-03-01

    The diffraction method of observing elementary excitations in crystals has been applied to the study of one-phonon thermal diffuse scattering from pyrolytic graphite on a high resolution pulsed neutron diffractometer. The variation of the phase velocity of sound as a function of direction in the crystal and efficient method of determining sound velocities in crystals under extreme conditions. (author)

  11. Interactions of polyethylene glycols with water studied by measurements of density and sound velocity

    International Nuclear Information System (INIS)

    Ayranci, Erol; Sahin, Melike

    2008-01-01

    Densities and sound velocities of ethylene glycol (EG) and polyethylene glycols (PEGs) of molecular weight 200, 300, 400, 550, 600, 1000, 1450, 3350, 8000, and 10,000 at (288.15, 298.15, and 308.15) K were measured with high precision vibrating tube densimeter and sound velocity measuring device. They were used to evaluate apparent molar volumes, V o , and apparent molar isentropic compressibilities, K ΦS . Infinite dilution values of these parameters, V o 0 , and K ΦS 0 , were obtained from their plot as a function of molality. The variations of V o 0 , and K ΦS 0 , with the number of repeating units in PEGs and with temperature were examined. Comparison of the experimentally obtained data was made with the available literature data and also with some values predicted according to group additivity approach. The results were interpreted in terms of hydration and conformational effects of PEGs in water. A correlation was also examined between V o 0 or K ΦS 0 values of PEGs in water and equilibrium moisture contents of PEGs as well as the water vapor permeabilities (WVP) of edible films containing PEGs

  12. Sound velocity and equation-of-state measurements in high pressure fluid and solid helium

    International Nuclear Information System (INIS)

    Liebenberg, D.H.; Mills, R.L.; Bronson, J.C.

    1979-01-01

    A piston--cylinder apparatus was used to obtain P, V, T, and simultaneous values of longitudinal sound velocity in helium fluid throughout the ranges 75 to 300 0 K and 3 to 20 kbar. Some 670 data sets were obtained for the fluid and used in a double-process least-squares fit to an equation of state of the Benedict type. Additional measurements extended across the melting line into the solid phase at pressures up to 18 kbar. Measurements of the compressibility are compared with those obtained by Stewart along the 4 0 K isotherm up to 20 kbar. We discuss the use of helium as a pressure medium in high-pressure diamond anvil cells. Essentially no data are given

  13. Measurement of sound velocity on metal surfaces by impulsive stimulated Brillouin scattering

    International Nuclear Information System (INIS)

    Shimada, Yukihiro; Murakami, Hiroshi; Nishimura, Akihiko

    2005-01-01

    Impulsive stimulated Brillouin Scattering (ISBS) experiment was performed in order to measure acoustic waves on metal surfaces. The ISBS technique offers robust method of obtaining acoustic velocities without physical contact. The generation and detection mechanism were discussed. (author)

  14. Measurement of sound velocity made easy using harmonic resonant frequencies with everyday mobile technology

    Science.gov (United States)

    Hirth, Michael; Kuhn, Jochen; Müller, Andreas

    2015-02-01

    Recent articles about smartphone experiments have described their applications as experimental tools in different physical contexts.1-4 They have established that smartphones facilitate experimental setups, thanks to the small size and diverse functions of mobile devices, in comparison to setups with computer-based measurements. In the experiment described in this article, the experimental setup is reduced to a minimum. The objective of the experiment is to determine the speed of sound with a high degree of accuracy using everyday tools. An article published recently proposes a time-of-flight method where sound or acoustic pulses are reflected at the ends of an open tube.5 In contrast, the following experiment idea is based on the harmonic resonant frequencies of such a tube, simultaneously triggered by a noise signal.

  15. Nuclear magnetic resonance and sound velocity measurements of chalk saturated with magnesium rich brine

    DEFF Research Database (Denmark)

    Katika, Konstantina; Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    2013-01-01

    The use of low field Nuclear Magnetic Resonance (NMR) to determine petrophysical properties of reservoirs has proved to be a good technique. Together with sonic and electrical resistivity measurements, NMR can contribute to illustrate the changes on chalk elasticity due to different pore water...... solutions of the same ionic strength. Saturation with a solution that contained divalent ions caused a major shift on the distribution of the relaxation time. The changes were probably due to precipitats forming extra internal surface in the sample. Sonic velocities were relatively low in the MgCl2 solution...

  16. Simultaneous sound velocity and thickness measurement by the ultrasonic pitch-catch method for corrosion-layer-forming polymeric materials.

    Science.gov (United States)

    Kusano, Masahiro; Takizawa, Shota; Sakai, Tetsuya; Arao, Yoshihiko; Kubouchi, Masatoshi

    2018-01-01

    Since thermosetting resins have excellent resistance to chemicals, fiber reinforced plastics composed of such resins and reinforcement fibers are widely used as construction materials for equipment in chemical plants. Such equipment is usually used for several decades under severe corrosive conditions so that failure due to degradation may result. One of the degradation behaviors in thermosetting resins under chemical solutions is "corrosion-layer-forming" degradation. In this type of degradation, surface resins in contact with a solution corrode, and some of them remain asa corrosion layer on the pristine part. It is difficult to precisely measure the thickness of the pristine part of such degradation type materials by conventional pulse-echo ultrasonic testing, because the sound velocity depends on the degree of corrosion of the polymeric material. In addition, the ultrasonic reflection interface between the pristine part and the corrosion layer is obscure. Thus, we propose a pitch-catch method using a pair of normal and angle probes to measure four parameters: the thicknesses of the pristine part and the corrosion layer, and their respective sound velocities. The validity of the proposed method was confirmed by measuring a two-layer sample and a sample including corroded parts. The results demonstrate that the pitch-catch method can successfully measure the four parameters and evaluate the residual thickness of the pristine part in the corrosion-layer-forming sample. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Tables of the velocity of sound in sea water

    CERN Document Server

    Bark, L S; Meister, N A

    1964-01-01

    Tables of the Velocity of Sound in Sea Water contains tables of the velocity of sound in sea water computed on a ""Strela-3"" high-speed electronic computer and a T-5 tabulator at the Computational Center of the Academy of Sciences. Knowledge of the precise velocity of sound in sea water is of great importance when investigating sound propagations in the ocean and when solving practical problems involving the use of hydro-acoustic devices. This book demonstrates the computations made for the velocity of sound in sea water, which can be found in two ways: by direct measurement with the aid of s

  18. Thermodynamic measurement of the sound velocity of a Bose gas across the transition to Bose–Einstein condensation

    Science.gov (United States)

    Fritsch, A. R.; Tavares, P. E. S.; Vivanco, F. A. J.; Telles, G. D.; Bagnato, V. S.; Henn, E. A. L.

    2018-05-01

    We present an alternative method for determining the sound velocity in atomic Bose–Einstein condensates, based on thermodynamic global variables. The total number of trapped atoms was as a function of temperature carefully studied across the phase transition, at constant volume. It allowed us to evaluate the sound velocity resulting in consistent values from the quantum to classical regime, in good agreement with previous results found in literature. We also provide some insight about the dominant sound mode (thermal or superfluid) across a wide temperature range.

  19. Measurement of Density, Sound Velocity, Surface Tension, and Viscosity of Freely Suspended Supercooled Liquids

    Science.gov (United States)

    Trinh, E. H.

    1995-01-01

    Non-contact methods have been implemented in conjunction with levitation techniques to carry out the measurement of the macroscopic properties of liquids significantly cooled below their nominal melting point. Free suspension of the sample and remote methods allow the deep excursion into the metastable liquid state and the determination of its thermophysical properties. We used this approach to investigate common substances such as water, o-terphenyl, succinonitrile, as well as higher temperature melts such as molten indium, aluminum and other metals. Although these techniques have thus far involved ultrasonic, electromagnetic, and more recently electrostatic levitation, we restrict our attention to ultrasonic methods in this paper. The resulting magnitude of maximum thermal supercooling achieved have ranged between 10 and 15% of the absolute temperature of the melting point for the materials mentioned above. The physical properties measurement methods have been mostly novel approaches, and the typical accuracy achieved have not yet matched their standard equivalent techniques involving contained samples and invasive probing. They are currently being refined, however, as the levitation techniques become more widespread, and as we gain a better understanding of the physics of levitated liquid samples.

  20. A particle velocity sensor to measure the sound from a structure in the presence of background noise

    NARCIS (Netherlands)

    de Bree, H.E.; Druyvesteyn, W.F.

    2005-01-01

    The performance (or quality) of a product is often checked by measuring the radiated sound (noise) from the vibrating structure. Often this test has to be done in an environment with background noise, which makes the measurement difficult. When using a (pressure) microphone the background noise can

  1. Precise zero-sound velocity measurements in the A and A1 phases of 3He near T/sub c/

    International Nuclear Information System (INIS)

    Berg, R.F.; Ihas, G.G.

    1983-01-01

    The authors have made phase-velocity change measurements for 5 and 15 MHz zero sound within a few microkelvin of the 3 He superfluid transition, T/sub c/, at 31.1 bar. The results show no marked feature at homega = 2Δ(T). However, there is a marked reduction in the slope of dc/dT upon passing from the A-phase into the Al-phase. 2 references

  2. Second sound velocities in superfluid 3He-4He solutions

    International Nuclear Information System (INIS)

    Dikina, L.S.; Kotenev, G.Ya.; Rudavskij, Eh.Ya.

    1978-01-01

    The velocities of the second sound in the superfluid He 3 -He 4 solutions were measured by the pulse method in the range of temperatures from 1.3 K to Tsub(lambda) and for He 3 concentrations up to 13%.The results obtained supplemented by those available before give the complete description of the concentration and temperature dependences of the second sound velocity in superfluid He 3 -He 4 solutions. The comprehensive comparison of the experimental data on the velocity of the second sound with the theoretical calculations for the superfluid solutions with arbitrary content of He 3 is performed. The good agreement is found between experiment and the theory. The experimental data obtained are used for determination of the potential, which determines the properties of the superfluid solutions

  3. Comparative sound velocity measurements between porous rock and fully-dense material under crustal condition: The cases of Darley Dale sandstone and copper block

    Science.gov (United States)

    Kung, J.; Chien, Y. V.; Wu, W.; Dong, J.; Chang, Y.; Tsai, C.; Yang, M.; Wang, K.

    2012-12-01

    Previous studies showed that the voids and their geometry in the sedimentary rocks have great influence on the compressibility of rock, which reflects on its elastic velocities. Some models were developed to discuss the relations among velocity, porosity and void geometry. Therefore, the information of porosity, and void geometry and its distribution in rock is essential for understanding how the elastic properties of porous rocks affected by their poregeometry. In this study, we revisited a well-studied porous rock, Darley Dale sandstone, which has been studied by different groups with different purposes. Most of them are the deformation experiments. Different from previous studies, we measured the sound velocity of Darley dale sandstone under hydrostatic conditions. Also, we employed different techniques to investigate the pore geometry and porosity of Darley Dale sandstone to gain the insight of velocity changing behavior under the crustal conditions. Here, we measured a fully-dense copper block for a comparison. We performed X-ray CT scanning (XCT) to image the pore space of sandstone to construct the 3-D image of pore geometry, distribution and the pore size. The CT image data are allowed us to estimate the porosity of sandstone, too. One the other hand, the porosity of sample was measured using imbibitions method at ambient conditions and helium porosimeter at high pressure (up to 150 MPa). A set of specimens were cored from Darley Dale sandstone block. P and S wave velocities of specimens were measured at ambient conditions. We also performed high pressure velocity measurements on a selected rock specimen and a copper block up to 150 MPa under dry condition. Porosity of a set of rock specimens measured by imbibitions method was spanned from 6% to 15%, largely distributed within a range of 8%-11%. Compared the porosity obtained from three different techniques, imbibitions method, helium porosimeter and XCT, values from those measurements are in good agreement

  4. Sound velocity in potassium hydroxide aqueous solution

    International Nuclear Information System (INIS)

    Tsapuryan, Kh.D.; Aleksandrov, A.A.; Kochetkov, A.I.

    1992-01-01

    Measurements of ultrasonic velocities in potassium hydroxide aqueous solutions are carried out within the frames of studies on improvement of water chemistry in NPP cooling systems. Method of echo pulses superposition with acoustic path length of 41.447 mm is used for measurements. The measurements are performed at 2.6 MHz frequency. Complex temperature dependence of ultrasonic velocity is determined. Ultrasonic velocity dependence on pressure is close to linear one. The formula for calculation of thermodynamic properties of the studied solutions on the basis of experimental data obtained is proposed

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

    Science.gov (United States)

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

    2016-11-01

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

  6. Temperature dependence of sound velocity in yttrium ferrite

    International Nuclear Information System (INIS)

    L'vov, V.A.

    1979-01-01

    The effect of the phonon-magnon and phonon-phonon interoctions on the temperature dependence of the longitudinal sound velocity in yttrium ferrite is considered. It has been shown that at low temperatures four-particle phonon-magnon processes produce the basic contribution to renormalization of the sound velocity. At higher temperatures the temperature dependence of the sound velocity is mainly defined by phonon-phonon processes

  7. The measurement of low air flow velocities

    NARCIS (Netherlands)

    Aghaei, A.; Mao, X.G.; Zanden, van der A.J.J.; Schaik, W.H.J.; Hendriks, N.A.

    2005-01-01

    Air flow velocity is measured with an acoustic sensor, which can be used especially for measuring low air flow velocities as well as the temperature of the air simultaneously. Two opposite transducers send a sound pulse towards each other. From the difference of the transit times, the air flow

  8. Ultrasonic velocity measurements in expanded liquid mercury

    International Nuclear Information System (INIS)

    Suzuki, K.; Inutake, M.; Fujiwaka, S.

    1977-10-01

    In this paper we present the first results of the sound velocity measurements in expanded liquid mercury. The measurements were made at temperatures up to 1600 0 C and pressures up to 1700 kg/cm 2 by means of an ultrasonic pulse transmission/echo technique which was newly developed for such high temperature/pressure condition. When the density is larger than 9 g/cm 3 , the observed sound velocity decreases linearly with decreasing density. At densities smaller than 9 g/cm 3 , the linear dependence on the density is no longer observed. The observed sound velocity approaches a minimum near the liquid-gas critical point (rho sub(cr) asymptotically equals 5.5 g/cm 3 ). The existing theories for sound velocity in liquid metals fail to explain the observed results. (auth.)

  9. Sound field separation with a double layer velocity transducer array (L)

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn

    2011-01-01

    of the array. The technique has been examined and compared with direct velocity based reconstruction, as well as with a technique based on the measurement of the sound pressure and particle velocity. The double layer velocity method circumvents some of the drawbacks of the pressure-velocity based...

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

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Feng, E-mail: xifeng@caep.cn; Jin, Ke; Cai, Lingcang, E-mail: cai-lingcang@aliyun.com; Geng, Huayun; Tan, Ye; Li, Jun [National Key Laboratory of Shock Waves and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102 Mianyang, Sichuan 621999 (China)

    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.

  11. Sound velocity variation as function of polarization state in Lead Zirconate Titanate (PZT) Ceramics

    International Nuclear Information System (INIS)

    Essolaani, W; Farhat, N

    2012-01-01

    There are several ultrasonic techniques to measure the sound velocity, for example, the pulse-echo method. In such method, the size of transducer used to measure the sound velocity must be in the same order of the sample size. If not, the incompatibility of sizes becomes an error source of the sound velocity measurement. In this work, the Laser Induced Pressure Pulse (LIPP) method is used as ultrasonic method. This method has been very useful for studying the spatial distribution of charges and polarization in dielectrics. We take advantage of the fact that the method allows the sound velocity measurement, to study its variation as function of polarization state in (PZT) ceramics. In a sample with a known thickness e, the sound velocity ν is deduced from the measurement of the transit time T. The sound velocity depends on the elastic constants which in turn they depend on poling conditions. Thus, the variation of the sound velocity is related to the direction and the amplitude of the polarization.

  12. Microflown based monopole sound sources for reciprocal measurements

    NARCIS (Netherlands)

    Bree, H.E. de; Basten, T.G.H.

    2008-01-01

    Monopole sound sources (i.e. omni directional sound sources with a known volume velocity) are essential for reciprocal measurements used in vehicle interior panel noise contribution analysis. Until recently, these monopole sound sources use a sound pressure transducer sensor as a reference sensor. A

  13. Microscopic theory of longitudinal sound velocity in charge ordered manganites

    International Nuclear Information System (INIS)

    Rout, G C; Panda, S

    2009-01-01

    A microscopic theory of longitudinal sound velocity in a manganite system is reported here. The manganite system is described by a model Hamiltonian consisting of charge density wave (CDW) interaction in the e g band, an exchange interaction between spins of the itinerant e g band electrons and the core t 2g electrons, and the Heisenberg interaction of the core level spins. The magnetization and the CDW order parameters are considered within mean-field approximations. The phonon Green's function was calculated by Zubarev's technique and hence the longitudinal velocity of sound was finally calculated for the manganite system. The results show that the elastic spring involved in the velocity of sound exhibits strong stiffening in the CDW phase with a decrease in temperature as observed in experiments.

  14. Microscopic theory of longitudinal sound velocity in charge ordered manganites

    Energy Technology Data Exchange (ETDEWEB)

    Rout, G C [Condensed Matter Physics Group, PG Department of Applied Physics and Ballistics, FM University, Balasore 756 019 (India); Panda, S, E-mail: gcr@iopb.res.i [Trident Academy of Technology, F2/A, Chandaka Industrial Estate, Bhubaneswar 751 024 (India)

    2009-10-14

    A microscopic theory of longitudinal sound velocity in a manganite system is reported here. The manganite system is described by a model Hamiltonian consisting of charge density wave (CDW) interaction in the e{sub g} band, an exchange interaction between spins of the itinerant e{sub g} band electrons and the core t{sub 2g} electrons, and the Heisenberg interaction of the core level spins. The magnetization and the CDW order parameters are considered within mean-field approximations. The phonon Green's function was calculated by Zubarev's technique and hence the longitudinal velocity of sound was finally calculated for the manganite system. The results show that the elastic spring involved in the velocity of sound exhibits strong stiffening in the CDW phase with a decrease in temperature as observed in experiments.

  15. Method and Apparatus of Measuring Velocity and Sound Attenuation Coefficient in Bulk Materials Based on the Analysis of the Structure of Sound-Insulation Materials on the Basis of Perlite

    Science.gov (United States)

    Kapranov, B. I.; Mashanov, A. P.

    2017-04-01

    This paper presents the results of research and describes the apparatus for measuring the acoustic characteristics of bulk materials. Ultrasound, it has passed through a layer of bulk material, is further passes through an air gap. The presence of air gap prevents from measuring tract mechanical contacts, but complicates the measurement technology Studies were conducted on the example of measuring the acoustic characteristics of the widely used perlite-based sound-proofing material.

  16. Sound velocity and attenuation in single-crystal YBa2Cu3O/sub 7-//sub δ/

    International Nuclear Information System (INIS)

    Shi, X.D.; Yu, R.C.; Wang, Z.Z.; Ong, N.P.; Chaikin, P.M.

    1989-01-01

    We have used a modified vibrating reed technique to measure the temperature dependence of the sound velocity and attenuation for modes corresponding to the Young's modulus and c/sub 14/ shear modulus of single crystals of YBa 2 Cu 3 O/sub 7-//sub δ/. The Young's sound velocity shows a tremendous softening during the superconducting transition: a smeared discontinuity of as high as 190 ppm. Below the transition, the temperature dependences of both sound velocities harden considerably. The discontinuities of the sound velocities and their temperature derivatives at T/sub c/ are related to the specific-heat jump at the superconducting transition

  17. Erratum to: Elastic and piezoelectric properties, sound velocity and ...

    Indian Academy of Sciences (India)

    Erratum to: Elastic and piezoelectric properties, sound velocity and Debye temperature of (B3) BBi compound under pressure. S DAOUD1,∗, N BIOUD2 and N LEBGAA2. 1Faculté des Sciences et de la Technologie, Université de Bordj Bou Arreridj, 34000, Algeria. 2Laboratoire d'Optoélectronique & Composants, Université ...

  18. The sound velocity in an equilibrium hadron gas

    OpenAIRE

    Prorok, Dariusz; Turko, Ludwik

    2001-01-01

    We calculate the velocity of sound in an ideal gas of massive hadrons with non-vanishing baryon number. The gas is in thermal and chemical equilibrium. Also we show that the temperature dependence $T(\\tau) \\cong T_{0} \\cdot ({\\tau_{0} \\over \\tau})^{c_{s}^{2}}$ is approximately valid, when the gas expands longitudinally according to the Bjorken law.

  19. Acoustic methods for measuring bullet velocity

    OpenAIRE

    Courtney, Michael

    2008-01-01

    This article describes two acoustic methods to measure bullet velocity with an accuracy of 1% or better. In one method, a microphone is placed within 0.1 m of the gun muzzle and a bullet is fired at a steel target 45 m away. The bullet's flight time is the recorded time between the muzzle blast and sound of hitting the target minus the time for the sound to return from the target to the microphone. In the other method, the microphone is placed equidistant from both the gun muzzle and the stee...

  20. Superfluid hydrodynamics of polytropic gases: dimensional reduction and sound velocity

    International Nuclear Information System (INIS)

    Bellomo, N; Mazzarella, G; Salasnich, L

    2014-01-01

    Motivated by the fact that two-component confined fermionic gases in Bardeen–Cooper–Schrieffer–Bose–Einstein condensate (BCS–BEC) crossover can be described through an hydrodynamical approach, we study these systems—both in the cigar-shaped configuration and in the disc-shaped one—by using a polytropic Lagrangian density. We start from the Popov Lagrangian density and obtain, after a dimensional reduction process, the equations that control the dynamics of such systems. By solving these equations we study the sound velocity as a function of the density by analyzing how the dimensionality affects this velocity. (paper)

  1. Zero sound velocity in π, ρ mesons at different temperatures

    International Nuclear Information System (INIS)

    Dey, J.; Dey, M.; Tomio, L.; Araujo, C.F. de Jr.

    1994-07-01

    Sharp transitions are perhaps absent in QCD, so that one looks for physical quantities which may reflect the phase change. One such quantity is the sound velocity which was shown in lattice theory to become zero at the transition point for pure glue. We show that even in a simple bag model the sound velocity goes to zero at temperature T=T ν ≠ 0 and that the numerical value of this T ν depends on the nature of the meson. The average thermal energy of mesons go linearly with T near T ν , with much smaller slope for the pion. The T ν - s can be connected with the Boltzmann temperatures obtained from transverse momentum spectrum of these mesons in heavy ion collision at mid-rapidity. It would be interesting to check the presence of different T ν - s in present day finite T lattice theory. (author). 22 refs, 1 fig., 2 tabs

  2. Patch near field acoustic holography based on particle velocity measurements

    DEFF Research Database (Denmark)

    Zhang, Yong-Bin; Jacobsen, Finn; Bi, Chuan-Xing

    2009-01-01

    Patch near field acoustic holography (PNAH) based on sound pressure measurements makes it possible to reconstruct the source field near a source by measuring the sound pressure at positions on a surface. that is comparable in size to the source region of concern. Particle velocity is an alternative...... examines the use of particle velocity as the input of PNAH. Because the particle velocity decays faster toward the edges of the measurement aperture than the pressure does and because the wave number ratio that enters into the inverse propagator from pressure to velocity amplifies high spatial frequencies...

  3. SOUND VELOCITY and Other Data from USS STUMP DD-978) (NCEI Accession 9400069)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The sound velocity data in this accession were collected from USS STUMP DD-978 by US Navy. The sound velocity in water is analog profiles data that was recorded in...

  4. Ab initio calculation of the sound velocity of dense hydrogen: implications for models of Jupiter

    NARCIS (Netherlands)

    Alavi, A.; Parrinello, M.; Frenkel, D.

    1995-01-01

    First-principles molecular dynamics simulations were used to calculate the sound velocity of dense hydrogen, and the results were compared with extrapolations of experimental data that currently conflict with either astrophysical models or data obtained from recent global oscillation measurements of

  5. Sound intensity and its measurement

    DEFF Research Database (Denmark)

    Jacobsen, Finn

    1997-01-01

    The paper summarises the basic theory of sound intensity and its measurement and gives an overview of the state of the art with particular emphasis on recent developments in the field. Eighty references are given, most of which to literature published in the past two years. The paper describes...

  6. Ultrasonic sound speed of hydrating calcium sulphate hemihydrate; part 2, the correlation of sound velocity to hydration degree

    NARCIS (Netherlands)

    de Korte, A.C.J.; Brouwers, Jos; Fischer, H.B; Matthes, C.; Beuthan, C.

    2011-01-01

    In this article the sound velocity through a mix is correlated to the hydration degree of the mix. Models are presented predicting the sound velocity through fresh slurries and hardened products. These two states correspond to the starting and finishing point of the hydration process. The present

  7. Ultrasonic sound speed of hydrating calcium sulphate hemihydrate; Part 2, The correlation of sound velocity to hydration degree

    NARCIS (Netherlands)

    Korte, de A.C.J.; Brouwers, H.J.H.; Fischer, H.B.; Mattes, Chr.; Beutha, C.

    2011-01-01

    In this article the sound velocity through a mix is correlated to the hydration degree of the mix. Models are presented predicting the sound velocity through fresh slurries and hardened products. These two states correspond to the starting and finishing point of the hydration process. The present

  8. Effects of heat treatment to the sound velocity and microstructural changes of ASTM A516 steels

    International Nuclear Information System (INIS)

    Norasiah Abdul Kasim; Azali Muhammad; Amry Amin Abas; Zaiton Selamat

    2010-01-01

    Full-text: The used of ultrasonic testing as a thickness measurement for structural components (pipeline and pressure vessel) is among the popular inspection tool widely use in the industrial power plant such as at petrochemical and nuclear power plant. Currently, there are cases where the thickness grows and the result will affect the reliability of the test. There are many factors that can affect the reliability of measurement. One of it is the material under test itself. In the Malaysian Nuclear Agency, initial efforts are underway to study the understanding on the effects of heat treatment to the sound velocity and microstructure changes of ASTM A516 steel. Few samples of thin square shaped prepared were heat treated under the following conditions: austenitization at 9800 degree Celsius - 2 hours, quenching; tempering at various temperature 4000, 5000, 6000 and 7000 degree Celsius. The results show that the microstructure changes and samples exhibit different sound velocity at different heat treatment. (author)

  9. Liquid structure and temperature invariance of sound velocity in supercooled Bi melt

    International Nuclear Information System (INIS)

    Emuna, M.; Mayo, M.; Makov, G.; Greenberg, Y.; Caspi, E. N.; Yahel, E.; Beuneu, B.

    2014-01-01

    Structural rearrangement of liquid Bi in the vicinity of the melting point has been proposed due to the unique temperature invariant sound velocity observed above the melting temperature, the low symmetry of Bi in the solid phase and the necessity of overheating to achieve supercooling. The existence of this structural rearrangement is examined by measurements on supercooled Bi. The sound velocity of liquid Bi was measured into the supercooled region to high accuracy and it was found to be invariant over a temperature range of ∼60°, from 35° above the melting point to ∼25° into the supercooled region. The structural origin of this phenomenon was explored by neutron diffraction structural measurements in the supercooled temperature range. These measurements indicate a continuous modification of the short range order in the melt. The structure of the liquid is analyzed within a quasi-crystalline model and is found to evolve continuously, similar to other known liquid pnictide systems. The results are discussed in the context of two competing hypotheses proposed to explain properties of liquid Bi near the melting: (i) liquid bismuth undergoes a structural rearrangement slightly above melting and (ii) liquid Bi exhibits a broad maximum in the sound velocity located incidentally at the melting temperature

  10. Instrument for measuring flow velocities

    International Nuclear Information System (INIS)

    Griffo, J.

    1977-01-01

    The design described here means to produce a 'more satisfying instrument with less cost' than comparable instruments known up to now. Instead of one single turbine rotor, two similar ones but with opposite blade inclination and sense of rotation are to be used. A cylindrical measuring body is carrying in its axis two bearing blocks whose shape is offering little flow resistance. On the shaft, supported by them, the two rotors run in opposite direction a relatively small axial distance apart. The speed of each rotor is picked up as pulse recurrence frequency by a transmitter and fed to an electronic measuring unit. Measuring errors as they are caused for single rotors by turbulent flow, profile distortion of the velocity, or viscous flow are to be eliminated by means of the contrarotating turbines and the subsequently added electronic unit, because in these cases the adulterating increase of the angular velocity of one rotor is compensated by a corresponding deceleration of the other rotor. The mean value then indicated by the electronic unit has high accurancy of measurement. (RW) [de

  11. Measuring probe for measurement of local velocities

    International Nuclear Information System (INIS)

    Casal, V.; Arnold, G.; Kirchner, R.; Kussmaul, H.; Miller, H.

    1988-03-01

    The report describes a method for measurement of local velocities. It bases on the detection of the propagation of a temperature pulse induced into the fluid. The method can also be applied in flowing liquid metals with superimposed magnetic field; in this case common measuring principles fail application. The measuring system discussed consists of, a measuring head, a heating system, amplifiers and a PC. The latter performs process operation, data sampling, and evaluation of velocity. The measuring head itself includes a miniaturized heater (as a pulse marker) heated by the heating system in a short pulse, and a number of thermocouples (sensors) for detection of signals. The design, construction, and examination of a developed measuring device is described. (orig.) [de

  12. Measuring the 'complexity'of sound

    Indian Academy of Sciences (India)

    Sounds in the natural environment form an important class of biologically relevant nonstationary signals. We propose a dynamic spectral measure to characterize the spectral dynamics of such non-stationary sound signals and classify them based on rate of change of spectral dynamics. We categorize sounds with slowly ...

  13. A particle velocity based method for separating all multi incoherent sound sources

    NARCIS (Netherlands)

    Winkel, J.C.; Yntema, Doekle Reinder; Druyvesteyn, W.F.; de Bree, H.E.

    2006-01-01

    In this paper we present a method to separate the contributions of different uncorrelated sound sources to the total sound field. When the contribution of each sound source to the total sound field is known, techniques with array-applications like direct sound field measurements or inverse acoustics

  14. Very low sound velocities in iron-rich (Mg,Fe)O: Implications for the core-mantle boundary region

    International Nuclear Information System (INIS)

    Wicks, J.K.; Jackson, J.M.; Sturhahn, W.

    2010-01-01

    The sound velocities of (Mg .16 Fe .84 )O have been measured to 121 GPa at ambient temperature using nuclear resonant inelastic x-ray scattering. The effect of electronic environment of the iron sites on the sound velocities were tracked in situ using synchrotron Moessbauer spectroscopy. We found the sound velocities of (Mg .16 Fe .84 )O to be much lower than those in other presumed mantle phases at similar conditions, most notably at very high pressures. Conservative estimates of the effect of temperature and dilution on aggregate sound velocities show that only a small amount of iron-rich (Mg,Fe)O can greatly reduce the average sound velocity of an assemblage. We propose that iron-rich (Mg,Fe)O be a source of ultra-low velocity zones. Other properties of this phase, such as enhanced density and dynamic stability, strongly support the presence of iron-rich (Mg,Fe)O in localized patches above the core-mantle boundary.

  15. Microstructure and sound velocity of Ti-N-O synthetic inclusions in Ti-6Al-4V

    International Nuclear Information System (INIS)

    Gigliotti, M.F.X.; Gilmore, R.S.; Perocchi, L.C.

    1994-01-01

    Nitrogen and oxygen stabilize the alpha phase in titanium. Regions within Ti alloy parts containing high local levels of N and O can stabilize a hard-alpha phase. The ultrasonic properties of titanium-nitrogen-oxygen inclusions within Ti-6Al-4V (Ti64) blocks were measured and related to inclusion chemistry. Sound velocities were measured on Ti-N-O alloy samples that had been prepared by powder metallurgy and ingot-melting techniques. The contributions to sound velocity from oxygen and nitrogen contents were determined. Then, Ti64 blocks were hot isostatic pressing (HIP) bonded to contain inclusions of the Ti-N-O alloys. The signal-to-noise ratios of reflections from uncracked inclusions were found to be an increasing function of inclusion interstitial content and were related to changes in sound velocity with inclusion chemistry. Measurements were made of the reflectance of titanium-nitrogen inclusions in titanium and Ti64

  16. Measuring the 'complexity' of sound

    Indian Academy of Sciences (India)

    cate that specialized regions of the brain analyse different types of sounds [1]. Music, ... The left panel of figure 1 shows examples of sound–pressure waveforms from the nat- ... which is shown in the right panels in the spectrographic representation using a 45 Hz .... Plot of SFM(t) vs. time for different environmental sounds.

  17. The universal sound velocity formula for the strongly interacting unitary Fermi gas

    International Nuclear Information System (INIS)

    Liu Ke; Chen Ji-Sheng

    2011-01-01

    Due to the scale invariance, the thermodynamic laws of strongly interacting limit unitary Fermi gas can be similar to those of non-interacting ideal gas. For example, the virial theorem between pressure and energy density of the ideal gas P = 2E/3V is still satisfied by the unitary Fermi gas. This paper analyses the sound velocity of unitary Fermi gases with the quasi-linear approximation. For comparison, the sound velocities for the ideal Boltzmann, Bose and Fermi gas are also given. Quite interestingly, the sound velocity formula for the ideal non-interacting gas is found to be satisfied by the unitary Fermi gas in different temperature regions. (general)

  18. Study on Water Distribution Imaging in the Sand Using Propagation Velocity of Sound with Scanning Laser Doppler Vibrometer

    Science.gov (United States)

    Sugimoto, Tsuneyoshi; Nakagawa, Yutaka; Shirakawa, Takashi; Sano, Motoaki; Ohaba, Motoyoshi; Shibusawa, Sakae

    2013-07-01

    We propose a method for the monitoring and imaging of the water distribution in the rooting zone of plants using sound vibration. In this study, the water distribution measurement in the horizontal and vertical directions in the soil layer was examined to confirm whether a temporal change in the volume water content of the soil could be estimated from a temporal changes in propagation velocity. A scanning laser Doppler vibrometer (SLDV) is used for measurement of the vibration velocity of the soil surface, because the highly precise vibration velocity measurement of several many points can be carried out automatically. Sand with a uniform particle size distribution is used for the soil, as it has high plasticity; that is, the sand can return to a dry state easily even if it is soaked with water. A giant magnetostriction vibrator or a flat speaker is used as a sound source. Also, a soil moisture sensor, which measures the water content of the soil using the electric permittivity, is installed in the sand. From the experimental results of the vibration measurement and soil moisture sensors, we can confirm that the temporal changes of the water distribution in sand using the negative pressure irrigation system in both the horizontal and vertical directions can be estimated using the propagation velocity of sound. Therefore, in the future, we plan to develop an insertion-type sound source and receiver using the acceleration sensors, and we intend to examine whether our method can be applied even in commercial soil with growing plants.

  19. Small scale features of sound velocity structure in the northern Arabian sea during February - May 1974

    Digital Repository Service at National Institute of Oceanography (India)

    Somayajulu, Y.K.; Rao, L.V.G.; Varadachari, V.V.R.

    at intermediate depths (200-400 m), influence the sound velocity structure and cause formation of an upper sound channel in the northern Arabian Sea. The Persian Gulf waters spread as tongues at 1 or 2 more levels (up to a limited extent), besides the prominent...

  20. Microscopic theory of longitudinal sound velocity in CDW and SDW ordered cuprate systems

    Energy Technology Data Exchange (ETDEWEB)

    Rout, G.C., E-mail: gcr@iopb.res.i [Condensed Matter Physics Group, PG Dept. of Applied Physics and Ballistics, FM University, Balasore 756 019 (India); Panda, S.K. [KD Science College, Pochilima, Hinjilicut 761 101, Ganjam, Orissa (India)

    2011-02-15

    Research highlights: {yields} Reported the study of the interplay of the CDW and SDW interactions in the high-Tc cuprates. {yields} The longitudinal velocity of sound is studied in the under-doped region. {yields} The velocity of sound exhibits suppression in both the CDW and SDW phases. {yields} Strong electron-phonon interaction is observed in normal phases. - Abstract: We address here the self-consistent calculation of the spin density wave and the charge density wave gap parameters for high-T{sub c} cuprates on the basis of the Hubbard model. In order to describe the experimental observations for the velocity of sound, we consider the phonon coupling to the conduction band in the harmonic approximation and then the expression for the temperature dependent velocity of sound is calculated from the real part of the phonon Green's function. The effects of the electron-phonon coupling, the frequency of the sound wave, the hole doping concentration, the CDW coupling and the SDW coupling parameters on the sound velocity are investigated in the pure CDW phase as well as in the co-existence phase of the CDW and SDW states. The results are discussed to explain the experimental observations.

  1. Microscopic theory of longitudinal sound velocity in CDW and SDW ordered cuprate systems

    International Nuclear Information System (INIS)

    Rout, G.C.; Panda, S.K.

    2011-01-01

    Research highlights: → Reported the study of the interplay of the CDW and SDW interactions in the high-Tc cuprates. → The longitudinal velocity of sound is studied in the under-doped region. → The velocity of sound exhibits suppression in both the CDW and SDW phases. → Strong electron-phonon interaction is observed in normal phases. - Abstract: We address here the self-consistent calculation of the spin density wave and the charge density wave gap parameters for high-T c cuprates on the basis of the Hubbard model. In order to describe the experimental observations for the velocity of sound, we consider the phonon coupling to the conduction band in the harmonic approximation and then the expression for the temperature dependent velocity of sound is calculated from the real part of the phonon Green's function. The effects of the electron-phonon coupling, the frequency of the sound wave, the hole doping concentration, the CDW coupling and the SDW coupling parameters on the sound velocity are investigated in the pure CDW phase as well as in the co-existence phase of the CDW and SDW states. The results are discussed to explain the experimental observations.

  2. Microscopic theory of longitudinal sound velocity in CDW and SDW ordered cuprate systems

    Energy Technology Data Exchange (ETDEWEB)

    Rout, G.C., E-mail: gcr@iopb.res.i [Condensed Matter Physics Group, PG Dept. of Applied Physics and Ballistics, FM University, Balasore 756 019 (India); Panda, S K [KD Science College, Pochilima, Hinjilicut 761 101, Ganjam, Orissa (India)

    2011-02-15

    Research highlights: {yields} Reported the study of the interplay of the CDW and SDW interactions in the high-Tc cuprates. {yields} The longitudinal velocity of sound is studied in the under-doped region. {yields} The velocity of sound exhibits suppression in both the CDW and SDW phases. {yields} Strong electron-phonon interaction is observed in normal phases. - Abstract: We address here the self-consistent calculation of the spin density wave and the charge density wave gap parameters for high-T{sub c} cuprates on the basis of the Hubbard model. In order to describe the experimental observations for the velocity of sound, we consider the phonon coupling to the conduction band in the harmonic approximation and then the expression for the temperature dependent velocity of sound is calculated from the real part of the phonon Green's function. The effects of the electron-phonon coupling, the frequency of the sound wave, the hole doping concentration, the CDW coupling and the SDW coupling parameters on the sound velocity are investigated in the pure CDW phase as well as in the co-existence phase of the CDW and SDW states. The results are discussed to explain the experimental observations.

  3. Sheep as a large animal ear model: Middle-ear ossicular velocities and intracochlear sound pressure.

    Science.gov (United States)

    Péus, Dominik; Dobrev, Ivo; Prochazka, Lukas; Thoele, Konrad; Dalbert, Adrian; Boss, Andreas; Newcomb, Nicolas; Probst, Rudolf; Röösli, Christof; Sim, Jae Hoon; Huber, Alexander; Pfiffner, Flurin

    2017-08-01

    Animals are frequently used for the development and testing of new hearing devices. Dimensions of the middle ear and cochlea differ significantly between humans and commonly used animals, such as rodents or cats. The sheep cochlea is anatomically more like the human cochlea in size and number of turns. This study investigated the middle-ear ossicular velocities and intracochlear sound pressure (ICSP) in sheep temporal bones, with the aim of characterizing the sheep as an experimental model for implantable hearing devices. Measurements were made on fresh sheep temporal bones. Velocity responses of the middle ear ossicles at the umbo, long process of the incus and stapes footplate were measured in the frequency range of 0.25-8 kHz using a laser Doppler vibrometer system. Results were normalized by the corresponding sound pressure level in the external ear canal (P EC ). Sequentially, ICSPs at the scala vestibuli and tympani were then recorded with custom MEMS-based hydrophones, while presenting identical acoustic stimuli. The sheep middle ear transmitted most effectively around 4.8 kHz, with a maximum stapes velocity of 0.2 mm/s/Pa. At the same frequency, the ICSP measurements in the scala vestibuli and tympani showed the maximum gain relative to the P EC (24 dB and 5 dB, respectively). The greatest pressure difference across the cochlear partition occurred between 4 and 6 kHz. A comparison between the results of this study and human reference data showed middle-ear resonance and best cochlear sensitivity at higher frequencies in sheep. In summary, sheep can be an appropriate large animal model for research and development of implantable hearing devices. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2009-02-01

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

  5. Sound velocity in the coolant of boiling nuclear reactors

    International Nuclear Information System (INIS)

    Proskuryakov, K.N.; Parshin, D.A.; Novikov, K.S.; Galivec, E.Yu.

    2009-01-01

    To prevent resonant interaction between acoustic resonance and natural frequencies of FE, FA and RI oscillations, it is necessary to determine the value of EACPO. Based on results of calculations of EACPO and natural frequencies of FR, FA and RI oscillations values, it would be possible to reveal the dynamical loadings on metal that are dangerous for the initiation of cracking process in the early stage of negative condition appearance. To calculate EACPO it is necessary to know the Speed Velocity in Coolant. Now we do not have any data about real values of such important parameter as pressure pulsations propagation velocity in two phase environments, especially in conditions with variations of steam content along the length of FR, with taking into account the type of local resistances, flow geometry etc. While areas of resonant interaction of the single-phase liquid coolant with equipment and internals vibrations are estimated well enough, similar estimations in the conditions of presence of a gas and steam phase in the liquid coolant are inconvenient till now. Paper presents results of calculation of velocity of pressure pulsations distribution in two-phase flow formed in core of RBMK-1000 reactors. Feature of the developed techniques is that not only thermodynamic factors and effect of a speed difference between water and steam in a two phase flow but also geometrical features of core, local resistance, non heterogeneity in the two phase environment and power level of a reactor are considered. Obtained results evidence noticeable decreasing of velocity propagation of pressure pulsations in the presence of steam actions in the liquids. Such estimations for real RC of boiling nuclear reactors with steam-liquid coolant are obtained for the first time. (author)

  6. Velocity measurement of conductor using electromagnetic induction

    International Nuclear Information System (INIS)

    Kim, Gu Hwa; Kim, Ho Young; Park, Joon Po; Jeong, Hee Tae; Lee, Eui Wan

    2002-01-01

    A basic technology was investigated to measure the speed of conductor by non-contact electromagnetic method. The principle of the velocity sensor was electromagnetic induction. To design electromagnet for velocity sensor, 2D electromagnetic analysis was performed using FEM software. The sensor output was analyzed according to the parameters of velocity sensor, such as the type of magnetizing currents and the lift-off. Output of magnetic sensor was linearly depended on the conductor speed and magnetizing current. To compensate the lift-off changes during measurement of velocity, the other magnetic sensor was put at the pole of electromagnet.

  7. Peculiar velocity measurement in a clumpy universe

    Science.gov (United States)

    Habibi, Farhang; Baghram, Shant; Tavasoli, Saeed

    Aims: In this work, we address the issue of peculiar velocity measurement in a perturbed Friedmann universe using the deviations from measured luminosity distances of standard candles from background FRW universe. We want to show and quantify the statement that in intermediate redshifts (0.5 deviations from the background FRW model are not uniquely governed by peculiar velocities. Luminosity distances are modified by gravitational lensing. We also want to indicate the importance of relativistic calculations for peculiar velocity measurement at all redshifts. Methods: For this task, we discuss the relativistic correction on luminosity distance and redshift measurement and show the contribution of each of the corrections as lensing term, peculiar velocity of the source and Sachs-Wolfe effect. Then, we use the SNe Ia sample of Union 2, to investigate the relativistic effects, we consider. Results: We show that, using the conventional peculiar velocity method, that ignores the lensing effect, will result in an overestimate of the measured peculiar velocities at intermediate redshifts. Here, we quantify this effect. We show that at low redshifts the lensing effect is negligible compare to the effect of peculiar velocity. From the observational point of view, we show that the uncertainties on luminosity of the present SNe Ia data prevent us from precise measuring the peculiar velocities even at low redshifts (z < 0.2).

  8. Sound velocities of the 23 Å phase at high pressure and implications for seismic velocities in subducted slabs

    Science.gov (United States)

    Cai, N.; Chen, T.; Qi, X.; Inoue, T.; Li, B.

    2017-12-01

    Dense hydrous phases are believed to play an important role in transporting water back into the deep interior of the Earth. Recently, a new Al-bearing hydrous Mg-silicate, named the 23 Å phase (ideal composition Mg12Al2Si4O16(OH)14), was reported (Cai et al., 2015), which could be a very important hydrous phase in subducting slabs. Here for the first time we report the measurements of the compressional and shear wave velocities of the 23 Å phase under applied pressures up to 14 GPa and room temperature, using a bulk sample with a grain size of less than 20 μm and density of 2.947 g/cm3. The acoustic measurements were conducted in a 1000-ton uniaxial split-cylinder multi-anvil apparatus using ultrasonic interferometry techniques (Li et al., 1996). The pressures were determined in situ by using an alumina buffer rod as the pressure marker (Wang et al., 2015). A dual-mode piezoelectric transducer enabled us to measure P and S wave travel times simultaneously, which in turn allowed a precise determination of the sound velocities and elastic bulk and shear moduli at high pressures. A fit to the acoustic data using finite strain analysis combined with a Hashin-Shtrikman (HS) bounds calculation yields: Ks0 = 113.3 GPa, G0 = 42.8 GPa, and K' = 3.8, G' = 1.9 for the bulk and shear moduli and their pressure derivatives. The velocities (especially for S wave) of this 23 Å phase (ambient Vp = 7.53 km/s, Vs = 3.72 km/s) are lower than those of phase A, olivine, pyrope, etc., while the Vp/Vs ratio (from 2.02 to 1.94, decreasing with increasing pressure) is quite high. These results suggest that a hydrous assemblage containing 23 Å phase should be distinguishable from a dry one at high pressure and temperature conditions relevant to Al-bearing subducted slabs.

  9. Pressure evolution of the high-frequency sound velocity in liquid water

    International Nuclear Information System (INIS)

    Krisch, M.; Sette, F.; D'Astuto, M.; Lorenzen, M.; Mermet, A.; Monaco, G.; Verbeni, R.; Loubeyre, P.; Le Toullec, R.; Ruocco, G.; Cunsolo, A.

    2002-01-01

    The high-frequency sound velocity v ∞ of liquid water has been determined to densities of 1.37 g/cm 3 by inelastic x-ray scattering. In comparison to the hydrodynamic sound velocity v 0 , the increase of v ∞ with density is substantially less pronounced, indicating that, at high density, the hydrogen-bond network is decreasingly relevant to the physical properties of liquid water. Furthermore, we observe an anomaly in v ∞ at densities around 1.12 g/cm 3 , contrasting the smooth density evolution of v 0

  10. Measurement of sound propagation in glass wool

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1995-01-01

    A new acoustic method for directly measuring the flow resistance, and the compressibility of fibrous materials such as glass wool, is given. Measured results for monochromatic sound in glass wool are presented and compared with theoretically calculated results. The agreement between experimental...

  11. The OPERA neutrino velocity measurement

    Energy Technology Data Exchange (ETDEWEB)

    Wonsak, Bjoern [Universitaet Hamburg (Germany)

    2012-07-01

    OPERA is a long-baseline neutrino oscillation experiment designed to find tau neutrinos appearing in a pure muon neutrino beam. Recently, a measurement of the flight time of the neutrinos between the CNGS at CERN and the OPERA detector at the LNGS has been performed. It was found that the neutrinos arrive at the detector significantly earlier in time than expected if travelling at the speed of light. In this talk, the main aspects of this measurement are presented, including timing and geodesy issues and the analysis procedure. An update concerning results with a fine structured time distribution of the beam is given, as well as latest information on some additional cross checks.

  12. Effect of temperature on density, sound velocity, and their derived properties for the binary systems glycerol with water or alcohols

    International Nuclear Information System (INIS)

    Negadi, Latifa; Feddal-Benabed, Badra; Bahadur, Indra; Saab, Joseph; Zaoui-Djelloul-Daouadji, Manel; Ramjugernath, Deresh; Negadi, Amina

    2017-01-01

    Highlights: • Densities (ρ) and sound velocities (u) for glycerol, +water, +methanol, or +ethanol systems were measured. • The derived properties (excess molar volume, isentropic compressibility and deviation in isentropic compressibility) were calculated. • The Redlich–Kister polynomial was used to fit the experimental results. - Abstract: Densities and sound velocities of three binary systems containing glycerol + (water, methanol, or ethanol) have been measured over the entire composition range at temperatures ranging from (283.15 to 313.15) K in 10 K intervals, at atmospheric pressure. A vibrating u-tube densimeter and sound velocity analyzer (Anton Paar DSA 5000M) was used for the measurements. Thermodynamic properties were derived from the measured data, viz. excess molar volume, isentropic compressibility, and deviation in isentropic compressibility. The property data were correlated with the Redlich-Kister polynomial. In all cases, the excess molar volumes and deviation in isentropic compressibility are negative over the entire composition range for all binary mixtures studied and become increasingly negative with an increase in the temperature. These properties provide important information about different interactions that take place between like-like, like-unlike and unlike-unlike molecules in the mixtures.

  13. Sound field separation with cross measurement surfaces.

    Directory of Open Access Journals (Sweden)

    Jin Mao

    Full Text Available With conventional near-field acoustical holography, it is impossible to identify sound pressure when the coherent sound sources are located on the same side of the array. This paper proposes a solution, using cross measurement surfaces to separate the sources based on the equivalent source method. Each equivalent source surface is built in the center of the corresponding original source with a spherical surface. According to the different transfer matrices between equivalent sources and points on holographic surfaces, the weighting of each equivalent source from coherent sources can be obtained. Numerical and experimental studies have been performed to test the method. For the sound pressure including noise after separation in the experiment, the calculation accuracy can be improved by reconstructing the pressure with Tikhonov regularization and the L-curve method. On the whole, a single source can be effectively separated from coherent sources using cross measurement.

  14. Sound power measurement and certification

    International Nuclear Information System (INIS)

    MacKinnon, A.

    1993-01-01

    It is anticipated that there will be a substantial growth in the exploitation of renewable energy from the wind over the next few years. A major factor in this expected growth is the environmental acceptance or otherwise of wind turbines and in particular their noise characteristics. It is generally accepted within the turbine community that reliable methods of measuring and quantifying a turbine's acoustic signature are essential if this exploitation is to be realised. This paper will seek to review current practice both in the UK and further afield and will describe the development of a practical and reliable test method, which will aid the Wind Turbine Manufacturer, Developer and Planner. (author)

  15. Superhilac real-time velocity measurements

    International Nuclear Information System (INIS)

    Feinberg, B.; Meaney, D.; Thatcher, R.; Timossi, C.

    1987-03-01

    Phase probes have been placed in several external beam lines at the LBL heavy ion linear accelerator (SuperHILAC) to provide non-destructive velocity measurements independent of the ion being accelerated. The existing system has been improved to provide the following features: a display refresh rate better than twice per second, a sensitive pseudo-correlation technique to pick out the signal from the noise, simultaneous measurements of up to four ion velocities when more than one beam is being accelerated, and a touch-screen operator interface. These improvements allow the system to be used as a routine tuning aid and beam velocity monitor

  16. Interferometric phase velocity measurements in the auroral electrojet

    International Nuclear Information System (INIS)

    Labelle, J.; Kinter, P.M.; Kelley, M.C.

    1986-01-01

    A double-probe electric field detector and two spatially separated fixed-bias Langmuir probes were flown on a Taurus-Tomahawk sounding rocket launched from Poker Flat Research Range in March 1982. Interesting wave data have been obtained from about 10 s of the downleg portion of the flight during which the rocket passed through the auroral electrojet. Here the electric field receiver and both density fluctuation (deltan/n) receivers responded to a broad band of turbulence centered at 105 km altitude and at frequencies generally below 4 kHz. Closer examination of the two deltan/n turbulent waveforms reveals that they are correlated, and from the phase difference between the two signals, the phase velocity of the waves in the rocket reference frame is inferred. The magnitude and direction of the observed phase velocity are consistent either with waves which travel at the ion sound speed (Csub(s)) or with waves which travel at the electron drift velocity. The observed phase velocity varies by about 50% over a 5 km altitude range - an effect which probably results from shear in the zonal neutral wind, although unfortunately no simultaneous neutral wind measurements exist to confirm this. (author)

  17. Reconstruction of the forehead acoustic properties in an Indo-Pacific humpback dolphin (Sousa chinensis), with investigation on the responses of soft tissue sound velocity to temperature.

    Science.gov (United States)

    Song, Zhongchang; Zhang, Yu; Berggren, Per; Wei, Chong

    2017-02-01

    Computed tomography (CT) imaging and ultrasound experimental measurements were combined to reconstruct the acoustic properties (density, velocity, and impedance) of the head from a deceased Indo-Pacific humpback dolphin (Sousa chinensis). The authors extracted 42 soft forehead tissue samples to estimate the sound velocity and density properties at room temperature, 25.0  °C. Hounsfield Units (HUs) of the samples were read from CT scans. Linear relationships between the tissues' HUs and velocity, and HUs and density were revealed through regression analyses. The distributions of the head acoustic properties at axial, coronal, and sagittal cross sections were reconstructed, suggesting that the forehead soft tissues were characterized by low-velocity in the melon, high-velocity in the muscle and connective tissues. Further, the sound velocities of melon, muscle, and connective tissue pieces were measured under different temperatures to investigate tissues' velocity response to temperature. The results demonstrated nonlinear relationships between tissues' sound velocity and temperature. This study represents a first attempt to provide general information on acoustic properties of this species. The results could provide meaningful information for understanding the species' bioacoustic characteristics and for further investigation on sound beam formation of the dolphin.

  18. The effect of isotopic mass on the velocity of sound in liquid Li

    International Nuclear Information System (INIS)

    McAlister, S.P.; Crozier, E.D.; Cochran, J.F.

    1976-01-01

    Results are presented for the velocity of ultrasound in liquid 6 Li- 7 Li alloys of composition 4.5, 49.7 and 99.9 at % Li for temperatures up to 700 0 C. At the melting point the ratio of the velocity of sound in 6 Li to that in 7 Li was found within experimental error to equal (M 7 /M 6 )sup(1/2), the result expected for classical liquids which differ only in the isotopic mass M. In the alloy of 49.7 at % 7 Li the sound velocity exceeded by 0.6% the value expected for a thermodynamically ideal alloy. This result is discussed in terms of the theoretical treatment by Parrinello et al, (J. Phys. C.: Solid St. Phys.; 7:2577 (1974)) of collective excitations in binary isotopic fluids. (author)

  19. First- and zero-sound velocity and Fermi liquid parameter F2s in liquid 3He determined by a path length modulation technique

    International Nuclear Information System (INIS)

    Hamot, P.J.; Lee, Y.; Sprague, D.T.

    1995-01-01

    We have measured the velocity of first- and zero-sound in liquid 3 He at 12.6 MHz over the pressure range of 0.6 to 14.5 bar using a path length modulation technique that we have recently developed. From these measurements, the pressure dependent value of the Fermi liquid parameter F 2 s was calculated and found to be larger at low pressure than previously reported. These new values of F 2 s indicate that transverse zero-sound is a propagating mode at all pressures. The new values are important for the interpretation of the frequencies of order parameter collective modes in the superfluid phases. The new acoustic technique permits measurements in regimes of very high attenuation with a sensitivity in phase velocity of about 10 ppm achieved by a feedback arrangement. The sound velocity is thus measured continuously throughout the highly attenuating crossover (ωt ∼ 1) regime, even at the lowest pressures

  20. Temperature dependence of velocity of sound in high-Tc superconductors in normal state

    International Nuclear Information System (INIS)

    Bishoyi, K.C.; Rout, G.C.; Behera, S.N.

    2002-01-01

    A microscopic theoretical calculation of temperature dependence of velocity of sound in high temperature superconductors is addressed in this paper. The influence of model parameters of the system in its normal phase is investigated through numerical calculations. The results at the room temperature as well as low temperatures (∼ 25 K), are discussed. The dimensionless parameters involved in the calculations are the electron-phonon coupling (g), staggered magnetic field (h), hybridization (V), position of the f-level (d), temperature (t) and the conduction band width (ω). The model Hamiltonian contains the antiferromagnetism in conduction electrons of cooper and the electron-phonon interaction through the hybridization between conduction electrons and f-electrons of impurity atoms. The phonon Green's functions are calculated by Zubarev's technique. The velocity of sound is calculated in the long wavelength and finite temperature limit. (author)

  1. Sound velocities of skiagite-iron-majorite solid solution to 56 GPa probed by nuclear inelastic scattering

    Science.gov (United States)

    Vasiukov, D. M.; Ismailova, L.; Kupenko, I.; Cerantola, V.; Sinmyo, R.; Glazyrin, K.; McCammon, C.; Chumakov, A. I.; Dubrovinsky, L.; Dubrovinskaia, N.

    2018-05-01

    High-pressure experimental data on sound velocities of garnets are used for interpretation of seismological data related to the Earth's upper mantle and the mantle transition zone. We have carried out a Nuclear Inelastic Scattering study of iron-silicate garnet with skiagite (77 mol%)-iron-majorite composition in a diamond anvil cell up to 56 GPa at room temperature. The determined sound velocities are considerably lower than sound velocities of a number of silicate garnet end-members, such as grossular, pyrope, Mg-majorite, andradite, and almandine. The obtained sound velocities have the following pressure dependencies: V p [km/s] = 7.43(9) + 0.039(4) × P [GPa] and V s [km/s] = 3.56(12) + 0.012(6) × P [GPa]. We estimated sound velocities of pure skiagite and khoharite, and conclude that the presence of the iron-majorite component in skiagite strongly decreases V s . We analysed the influence of Fe3+ on sound velocities of garnet solid solution relevant to the mantle transition zone and consider that it may reduce sound velocities up to 1% relative to compositions with only Fe2+ in the cubic site.

  2. A note on measurement of sound pressure with intensity probes

    DEFF Research Database (Denmark)

    Juhl, Peter; Jacobsen, Finn

    2004-01-01

    be improved under a variety of realistic sound field conditions by applying a different weighting of the two pressure signals from the probe. The improved intensity probe can measure the sound pressure more accurately at high frequencies than an ordinary sound intensity probe or an ordinary sound level meter......The effect of scattering and diffraction on measurement of sound pressure with "two-microphone" sound intensity probes is examined using an axisymmetric boundary element model of the probe. Whereas it has been shown a few years ago that the sound intensity estimated with a two-microphone probe...... is reliable up to 10 kHz when using 0.5 in. microphones in the usual face-to-face arrangement separated by a 12 mm spacer, the sound pressure measured with the same instrument will typically be underestimated at high frequencies. It is shown in this paper that the estimate of the sound pressure can...

  3. Velocity of sound in, and adiabatic compressibility of, Molten LiF-NaF, LiF-KF, NaF-KF mixtures

    International Nuclear Information System (INIS)

    Minchenko, V.I.; Konovalov, Y.V.; Smirnov, M.V.

    1986-01-01

    The authors measured the velocity of sound as a function of temperature at 1.5 zHM frequency in LiF-NaF, NaF-KF, LiF-KF melts over the entire range of their compositions. The measurements were made by comparison of the phases of a reference pulse signal and a signal reflected from the bottom of the crucible. The specified temperatures were maintained constant within plus or minus 1 degree. The sound conductor consisted of a cylindrical rod of sintered beryllium oxide, which does not interact with test melts. The study shows that the velocity of sound decreases linearly with increase of the temperature. The values of the constants of the empirical equations are presented in a table, with indication of the temperature range. The dependence of the velocity of sound on composition of the melts is shown, where isotherms for 1250 K are given as an example. Variation of the composition by 1-2 mole % leads to increase or decrease of the velocity of sound by 5-10 m

  4. Simple indicator to identify the environmental soundness of growth of consumption and technology: "eco-velocity of consumption".

    Science.gov (United States)

    Nansai, Keisuke; Kagawa, Shigemi; Suh, Sangwon; Inaba, Rokuta; Moriguchi, Yuichi

    2007-02-15

    Today's material welfare has been achieved at the expense of consumption of finite resources and generation of environmental burdens. Over the past few decades the volume of global consumption has grown dramatically, while at the same time technological advances have enabled products with greater efficiencies. These two directions of change, consumption growth and technological advance, are the foci of the present paper. Using quantitative measures for these two factors, we define a new indicator, "eco-velocity of consumption", analogous to velocity in physics. The indicator not only identifies the environmental soundness of consumption growth and technological advance but also indicates whether and to what extent our society is shifting toward sustainable consumption. This study demonstrates the practicability of the indicator through a case study in which we calculate the eco-velocities of Japanese household consumption in 2 years: 1995 and 2000. The rate of technological advance during the periods concerned is quantified in terms of the embodied carbon dioxide emission per yen of product. The results show that the current growth rate of Japanese household consumption is greater than the rate of technological advance to mitigate carbon dioxide emissions. The eco-velocities at the level of individual commodity groups are also examined, and the sources of changes in eco-velocity for each commodity are identified using structural decomposition analysis.

  5. Size and velocity measurements in combustion systems

    International Nuclear Information System (INIS)

    Levy, Y.; Timnat, Y.M.

    1986-01-01

    Two-phase flow measurements for size and velocity determination in combustion systems are discussed: the pedestal technique and phase Doppler anemometry (PDA) are described in detail. The experimental apparatus for the pedestal method includes the optical laser-Doppler anemometry (LDA) package and the electronic data acquisition system. The latter comprises three channels for recording the Doppler frequency, and the pedestal amplitude as well as the validation pulse. Results of measurements performed in a dump combustor, into which kerosene droplets were injected, are presented. The principle of the PDA technique is explained and validation experiments, using latex particles, are reported. Finally the two methods are compared

  6. Sound level measurements using smartphone "apps": Useful or inaccurate?

    Directory of Open Access Journals (Sweden)

    Daniel R Nast

    2014-01-01

    Full Text Available Many recreational activities are accompanied by loud concurrent sounds and decisions regarding the hearing hazards associated with these activities depend on accurate sound measurements. Sound level meters (SLMs are designed for this purpose, but these are technical instruments that are not typically available in recreational settings and require training to use properly. Mobile technology has made such sound level measurements more feasible for even inexperienced users. Here, we assessed the accuracy of sound level measurements made using five mobile phone applications or "apps" on an Apple iPhone 4S, one of the most widely used mobile phones. Accuracy was assessed by comparing application-based measurements to measurements made using a calibrated SLM. Whereas most apps erred by reporting higher sound levels, one application measured levels within 5 dB of a calibrated SLM across all frequencies tested.

  7. The use of the automation for experiments using computers: determination of sound velocity in air

    International Nuclear Information System (INIS)

    Valdes, R.; Valdes, P.; Clavelo, A.

    1998-01-01

    This article shows the use of IBM PCs joysticks in order to measure the speed of sound in the air. Electrical circuits and software are presented and both technical and methodological advantages of the proposed method are discussed. (Author) 19 refs

  8. Sound velocity and compressibility for lunar rocks 17 and 46 and for glass spheres from the lunar soil.

    Science.gov (United States)

    Schreiber, E; Anderson, O L; Sogat, N; Warren, N; Scholz, C

    1970-01-30

    Four experiments on lunar materials are reported: (i) resonance on glass spheres from the soil; (ii) compressibility of rock 10017; (iii) sound velocities of rocks 10046 and 10017; (iv) sound velocity of the lunar fines. The data overlap and are mutually consistent. The glass beads and rock 10017 have mechanical properties which correspond to terrestrial materials. Results of (iv) are consistent with low seismic travel times in the lunar maria. Results of analysis of the microbreccia (10046) agreed with the soil during the first pressure cycle, but after overpressure the rock changed, and it then resembled rock 10017. Three models of the lunar surface were constructed giving density and velocity profiles.

  9. Longitudinal sound velocities, elastic anisotropy, and phase transition of high-pressure cubic H2O ice to 82 GPa

    Science.gov (United States)

    Kuriakose, Maju; Raetz, Samuel; Hu, Qing Miao; Nikitin, Sergey M.; Chigarev, Nikolay; Tournat, Vincent; Bulou, Alain; Lomonosov, Alexey; Djemia, Philippe; Gusev, Vitalyi E.; Zerr, Andreas

    2017-10-01

    Water ice is a molecular solid whose behavior under compression reveals the interplay of covalent bonding in molecules and forces acting between them. This interplay determines high-pressure phase transitions, the elastic and plastic behavior of H2O ice, which are the properties needed for modeling the convection and internal structure of the giant planets and moons of the solar system as well as H2O -rich exoplanets. We investigated experimentally and theoretically elastic properties and phase transitions of cubic H2O ice at room temperature and high pressures between 10 and 82 GPa. The time-domain Brillouin scattering (TDBS) technique was used to measure longitudinal sound velocities (VL) in polycrystalline ice samples compressed in a diamond anvil cell. The high spatial resolution of the TDBS technique revealed variations of VL caused by elastic anisotropy, allowing us to reliably determine the fastest and the slowest sound velocity in a single crystal of cubic H2O ice and thus to evaluate existing equations of state. Pressure dependencies of the single-crystal elastic moduli Ci j(P ) of cubic H2O ice to 82 GPa have been obtained which indicate its hardness and brittleness. These results were compared with ab initio calculations. It is suggested that the transition from molecular ice VII to ionic ice X occurs at much higher pressures than proposed earlier, probably above 80 GPa.

  10. Sound source measurement by using a passive sound insulation and a statistical approach

    Science.gov (United States)

    Dragonetti, Raffaele; Di Filippo, Sabato; Mercogliano, Francesco; Romano, Rosario A.

    2015-10-01

    This paper describes a measurement technique developed by the authors that allows carrying out acoustic measurements inside noisy environments reducing background noise effects. The proposed method is based on the integration of a traditional passive noise insulation system with a statistical approach. The latter is applied to signals picked up by usual sensors (microphones and accelerometers) equipping the passive sound insulation system. The statistical approach allows improving of the sound insulation given only by the passive sound insulation system at low frequency. The developed measurement technique has been validated by means of numerical simulations and measurements carried out inside a real noisy environment. For the case-studies here reported, an average improvement of about 10 dB has been obtained in a frequency range up to about 250 Hz. Considerations on the lower sound pressure level that can be measured by applying the proposed method and the measurement error related to its application are reported as well.

  11. Transport processes and sound velocity in vibrationally non-equilibrium gas of anharmonic oscillators

    Science.gov (United States)

    Rydalevskaya, Maria A.; Voroshilova, Yulia N.

    2018-05-01

    Vibrationally non-equilibrium flows of chemically homogeneous diatomic gases are considered under the conditions that the distribution of the molecules over vibrational levels differs significantly from the Boltzmann distribution. In such flows, molecular collisions can be divided into two groups: the first group corresponds to "rapid" microscopic processes whereas the second one corresponds to "slow" microscopic processes (their rate is comparable to or larger than that of gasdynamic parameters variation). The collisions of the first group form quasi-stationary vibrationally non-equilibrium distribution functions. The model kinetic equations are used to study the transport processes under these conditions. In these equations, the BGK-type approximation is used to model only the collision operators of the first group. It allows us to simplify derivation of the transport fluxes and calculation of the kinetic coefficients. Special attention is given to the connection between the formulae for the bulk viscosity coefficient and the sound velocity square.

  12. Measurement of incident sound power using near field acoustic holography

    DEFF Research Database (Denmark)

    Jacobsen, Finn; Tiana Roig, Elisabet

    2009-01-01

    ; and it has always been regarded as impossible to measure the sound power that is incident on a wall directly. This paper examines a new method of determining this quantity from sound pressure measurements at positions on the wall using ‘statistically optimised near field acoustic holography’ (SONAH...

  13. Crack velocity measurement by induced electromagnetic radiation

    International Nuclear Information System (INIS)

    Frid, V.; Rabinovitch, A.; Bahat, D.

    2006-01-01

    Our model of electromagnetic radiation (EMR) emanated from fracture implies that EMR amplitude is proportional to crack velocity. Soda lime glass samples were tested under uniaxial tension. Comparison of crack velocity observed by Wallner line analysis and the peak amplitude of EMR signals registered during the test, showed very good correlation, validating this proportionality

  14. Crack velocity measurement by induced electromagnetic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Frid, V. [Deichmann Rock Mechanics Laboratory of the Negev, Geological and Environmental Sciences Department, Ben Gurion University of the Negev, Beer Sheva (Israel)]. E-mail: vfrid@bgu.ac.il; Rabinovitch, A. [Deichmann Rock Mechanics Laboratory of the Negev, Physics Department, Ben Gurion University of the Negev, Beer Sheva (Israel); Bahat, D. [Deichmann Rock Mechanics Laboratory of the Negev, Geological and Environmental Sciences Department, Ben Gurion University of the Negev, Beer Sheva (Israel)

    2006-07-31

    Our model of electromagnetic radiation (EMR) emanated from fracture implies that EMR amplitude is proportional to crack velocity. Soda lime glass samples were tested under uniaxial tension. Comparison of crack velocity observed by Wallner line analysis and the peak amplitude of EMR signals registered during the test, showed very good correlation, validating this proportionality.

  15. Analysis of photosynthate translocation velocity and measurement of weighted average velocity in transporting pathway of crops

    International Nuclear Information System (INIS)

    Ge Cailin; Luo Shishi; Gong Jian; Zhang Hao; Ma Fei

    1996-08-01

    The translocation profile pattern of 14 C-photosynthate along the transporting pathway in crops were monitored by pulse-labelling a mature leaf with 14 CO 2 . The progressive spreading of translocation profile pattern along the sheath or stem indicates that the translocation of photosynthate along the sheath or stem proceed with a range of velocities rather than with just a single velocity. The method for measuring the weighted average velocity of photosynthate translocation along the sheath or stem was established in living crops. The weighted average velocity and the maximum velocity of photosynthate translocation along the sheath in rice and maize were measured actually. (4 figs., 3 tabs.)

  16. Measuring the speed of sound in air using smartphone applications

    Science.gov (United States)

    Yavuz, A.

    2015-05-01

    This study presents a revised version of an old experiment available in many textbooks for measuring the speed of sound in air. A signal-generator application in a smartphone is used to produce the desired sound frequency. Nodes of sound waves in a glass pipe, of which one end is immersed in water, are more easily detected, so results can be obtained more quickly than from traditional acoustic experiments using tuning forks.

  17. [A focused sound field measurement system by LabVIEW].

    Science.gov (United States)

    Jiang, Zhan; Bai, Jingfeng; Yu, Ying

    2014-05-01

    In this paper, according to the requirement of the focused sound field measurement, a focused sound field measurement system was established based on the LabVIEW virtual instrument platform. The system can automatically search the focus position of the sound field, and adjust the scanning path according to the size of the focal region. Three-dimensional sound field scanning time reduced from 888 hours in uniform step to 9.25 hours in variable step. The efficiency of the focused sound field measurement was improved. There is a certain deviation between measurement results and theoretical calculation results. Focal plane--6 dB width difference rate was 3.691%, the beam axis--6 dB length differences rate was 12.937%.

  18. Sound exposure measurements using hearing-aid technology

    DEFF Research Database (Denmark)

    Jensen, Simon Boelt; Drastrup, Mads; Morales, Esteban Chávez

    2016-01-01

    scenarios. The purpose of this work is to document the use of a modified behind-the-ear (BTE) hearing-aid as a portable sound pressure level (SPL) meter. In order to obtain sound level measurements with a BTE device comparable to sound field values that can be used with existing risk assessment strategies...... levels of sound exposures are experienced in modern society in many different situations such as attending concerts, sport events and others. This leads to an interest in measurement devices which are discreet and simple to use, in order to assess sound exposures encountered in typical daily life......, differences due to microphone positions and the presence of a person in the measurement must be taken into account. The present study presents measurements carried out to document the characteristics of the BTE device, using the same framework presented in the ISO 11904 standard series. The responses...

  19. Plasma flow velocity measurements using a modulated Michelson interferometer

    International Nuclear Information System (INIS)

    Howard, J.

    1997-01-01

    This paper discusses the possibility of flow velocity reconstruction using passive spectroscopic techniques. We report some preliminary measurements of the toroidal flow velocity of hydrogen atoms in the RTP tokamak using a phase modulated Michelson interferometer. (orig.)

  20. Spindle vibration and sound field measurement using optical vibrometry

    OpenAIRE

    Tatar, Kourosh

    2008-01-01

    Mechanical systems often produce a considerable amount of vibration and noise. To be able to obtain a complete picture of the dynamic behaviour of these systems, vibration and sound measurements are of significant importance. Optical metrology is well-suited for non-intrusive measurements on complex objects. The development and the use of remote non-contact vibration measurement methods for spindles are described and vibration measurements on thin- walled structures and sound field measuremen...

  1. Analysis of acoustic sound signal for ONB measurement

    International Nuclear Information System (INIS)

    Park, S. J.; Kim, H. I.; Han, K. Y.; Chai, H. T.; Park, C.

    2003-01-01

    The onset of nucleate boiling (ONB) was measured in a test fuel bundle composed of several fuel element simulators (FES) by analysing the aquatic sound signals. In order measure ONBs, a hydrophone, a pre-amplifier, and a data acquisition system to acquire/process the aquatic signal was prepared. The acoustic signal generated in the coolant is converted to the current signal through the microphone. When the signal is analyzed in the frequency domain, each sound signal can be identified according to its origin of sound source. As the power is increased to a certain degree, a nucleate boiling is started. The frequent formation and collapse of the void bubbles produce sound signal. By measuring this sound signal one can pinpoint the ONB. Since the signal characteristics is identical for different mass flow rates, this method can be applicable for ascertaining ONB

  2. Pavement sound absorption measurements in the U.S.

    Science.gov (United States)

    2012-08-19

    In the U.S., the topic of pavement sound absorption in regard to tire-pavement noise has shown increased interest and research over the last several years. Four types of pavement sound absorption measurements with various applications are discussed: ...

  3. P--V--T and sound velocity data for fluid n-D2 in the range 75-300 K and 2-20 kbar

    International Nuclear Information System (INIS)

    Liebenberg, D.H.; Mills, R.L.; Bronson, J.C.

    1977-11-01

    Simultaneous static measurements of pressure, volume, temperature, and sound velocity are reported in deuterium fluid in the range 75 less than or equal to T less than or equal to 300K and 2 less than or equal to P less than or equal to 20 kbar [0.2 to 2.0 GPa]. The 1340 sets of data points along the 33 different isotherms are presented so that they may be available for use in equation-of-state development

  4. Comprehensive measures of sound exposures in cinemas using smart phones.

    Science.gov (United States)

    Huth, Markus E; Popelka, Gerald R; Blevins, Nikolas H

    2014-01-01

    Sensorineural hearing loss from sound overexposure has a considerable prevalence. Identification of sound hazards is crucial, as prevention, due to a lack of definitive therapies, is the sole alternative to hearing aids. One subjectively loud, yet little studied, potential sound hazard is movie theaters. This study uses smart phones to evaluate their applicability as a widely available, validated sound pressure level (SPL) meter. Therefore, this study measures sound levels in movie theaters to determine whether sound levels exceed safe occupational noise exposure limits and whether sound levels in movie theaters differ as a function of movie, movie theater, presentation time, and seat location within the theater. Six smart phones with an SPL meter software application were calibrated with a precision SPL meter and validated as an SPL meter. Additionally, three different smart phone generations were measured in comparison to an integrating SPL meter. Two different movies, an action movie and a children's movie, were measured six times each in 10 different venues (n = 117). To maximize representativeness, movies were selected focusing on large release productions with probable high attendance. Movie theaters were selected in the San Francisco, CA, area based on whether they screened both chosen movies and to represent the largest variety of theater proprietors. Measurements were analyzed in regard to differences between theaters, location within the theater, movie, as well as presentation time and day as indirect indicator of film attendance. The smart phone measurements demonstrated high accuracy and reliability. Overall, sound levels in movie theaters do not exceed safe exposure limits by occupational standards. Sound levels vary significantly across theaters and demonstrated statistically significant higher sound levels and exposures in the action movie compared to the children's movie. Sound levels decrease with distance from the screen. However, no influence on

  5. A New Filtering Algorithm Utilizing Radial Velocity Measurement

    Institute of Scientific and Technical Information of China (English)

    LIU Yan-feng; DU Zi-cheng; PAN Quan

    2005-01-01

    Pulse Doppler radar measurements consist of range, azimuth, elevation and radial velocity. Most of the radar tracking algorithms in engineering only utilize position measurement. The extended Kalman filter with radial velocity measureneut is presented, then a new filtering algorithm utilizing radial velocity measurement is proposed to improve tracking results and the theoretical analysis is also given. Simulation results of the new algorithm, converted measurement Kalman filter, extended Kalman filter are compared. The effectiveness of the new algorithm is verified by simulation results.

  6. A new method for measurement of granular velocities

    International Nuclear Information System (INIS)

    Nyborg Andersen, B.

    1984-01-01

    A new, supplementary method to measure granular velocities is presented. The method utilizes the Doppler shift caused by the line of sight component of the solar rotation to cause a wavelength shift through spectral lines as function of heliocentric angle. By measuring the center-to-limb variation of the granular intensity fluctations at different wavelength positions in the lines, the velocities are found. To do this, assumptions regarding the geometrical structure of the velocity and intensity fields have to be made. Preliminary application of the method results in a steep velocity gradient suggesting zero velocity at a hight of 200 km above tau 500 = 1. Possible causes are discussed

  7. Exterior sound level measurements of snowcoaches at Yellowstone National Park

    Science.gov (United States)

    2010-04-01

    Sounds associated with oversnow vehicles, such as snowmobiles and snowcoaches, are an important management concern at Yellowstone and Grand Teton National Parks. The John A. Volpe National Transportation Systems Centers Environmental Measurement a...

  8. Measuring Velocity and Acceleration Using Doppler Shift of a ...

    Indian Academy of Sciences (India)

    to be used to measure its velocity and acceleration. We also apply this method, as an example here, to spectral lines of the blue-shifted jet in micro-quasar SS433 and discuss the intricacies of these measurements. Key words. Doppler effect—measuring velocity and acceleration of the source— jet in SS433. 1. Introduction.

  9. RASS sound speed profile (SSP) measurements for use in outdoor sound propagation models

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, S G [Physics Department, University of Auckland (New Zealand); Huenerbein, S v; Waddington, D [Research Institute for the Built and Human Environment, University of Salford (United Kingdom)], E-mail: s.vonhunerbein@salford.ac.uk

    2008-05-01

    The performance of outdoor sound propagation models depends to a great extent on meteorological input parameters. In an effort to improve speed and accuracy, model output synthetic sound speed profiles (SSP) are commonly used depending on meteorological classification schemes. In order to use SSP measured by RASS in outdoor sound propagation models, the complex profiles need to be simplified. In this paper we extend an investigation on the spatial and temporal characteristics of the meteorological data set required to yield adequate comparisons between models and field measurements, so that the models can be fairly judged. Vertical SSP from RASS, SODAR wind profiles as well as mast wind and temperature data from a flat terrain site and measured over a period of several months are used to evaluate applicability of the logarithmic approximation for a stability classification scheme proposed by the HARMONOISE working group.

  10. RASS sound speed profile (SSP) measurements for use in outdoor sound propagation models

    International Nuclear Information System (INIS)

    Bradley, S G; Huenerbein, S v; Waddington, D

    2008-01-01

    The performance of outdoor sound propagation models depends to a great extent on meteorological input parameters. In an effort to improve speed and accuracy, model output synthetic sound speed profiles (SSP) are commonly used depending on meteorological classification schemes. In order to use SSP measured by RASS in outdoor sound propagation models, the complex profiles need to be simplified. In this paper we extend an investigation on the spatial and temporal characteristics of the meteorological data set required to yield adequate comparisons between models and field measurements, so that the models can be fairly judged. Vertical SSP from RASS, SODAR wind profiles as well as mast wind and temperature data from a flat terrain site and measured over a period of several months are used to evaluate applicability of the logarithmic approximation for a stability classification scheme proposed by the HARMONOISE working group

  11. Dynamics of the standard deviations of three wind velocity components from the data of acoustic sounding

    Science.gov (United States)

    Krasnenko, N. P.; Kapegesheva, O. F.; Shamanaeva, L. G.

    2017-11-01

    Spatiotemporal dynamics of the standard deviations of three wind velocity components measured with a mini-sodar in the atmospheric boundary layer is analyzed. During the day on September 16 and at night on September 12 values of the standard deviation changed for the x- and y-components from 0.5 to 4 m/s, and for the z-component from 0.2 to 1.2 m/s. An analysis of the vertical profiles of the standard deviations of three wind velocity components for a 6-day measurement period has shown that the increase of σx and σy with altitude is well described by a power law dependence with exponent changing from 0.22 to 1.3 depending on the time of day, and σz depends linearly on the altitude. The approximation constants have been found and their errors have been estimated. The established physical regularities and the approximation constants allow the spatiotemporal dynamics of the standard deviation of three wind velocity components in the atmospheric boundary layer to be described and can be recommended for application in ABL models.

  12. Laser vibrometry measurements of vibration and sound fields of a bowed violin

    Science.gov (United States)

    Gren, Per; Tatar, Kourosh; Granström, Jan; Molin, N.-E.; Jansson, Erik V.

    2006-04-01

    Laser vibrometry measurements on a bowed violin are performed. A rotating disc apparatus, acting as a violin bow, is developed. It produces a continuous, long, repeatable, multi-frequency sound from the instrument that imitates the real bow-string interaction for a 'very long bow'. What mainly differs is that the back and forward motion of the real bow is replaced by the rotating motion with constant velocity of the disc and constant bowing force (bowing pressure). This procedure is repeatable. It is long lasting and allows laser vibrometry techniques to be used, which measure forced vibrations by bowing at all excited frequencies simultaneously. A chain of interacting parts of the played violin is studied: the string, the bridge and the plates as well as the emitted sound field. A description of the mechanics and the sound production of the bowed violin is given, i.e. the production chain from the bowed string to the produced tone.

  13. Measuring velocity by differentiation of analog encoder signals

    NARCIS (Netherlands)

    Winarto, R.F.; Steinbuch, M.; Molengraft, van de M.J.G.

    2013-01-01

    In this report a new method for measuring velocities has been introduced. During the research in literature an overview has been made of the existing methods of measuring velocities. From this research, it can be concluded that a lot of existing approaches only work in specific settings. Besides

  14. Measuring Average Angular Velocity with a Smartphone Magnetic Field Sensor

    Science.gov (United States)

    Pili, Unofre; Violanda, Renante

    2018-01-01

    The angular velocity of a spinning object is, by standard, measured using a device called a tachometer. However, by directly using it in a classroom setting, the activity is likely to appear as less instructive and less engaging. Indeed, some alternative classroom-suitable methods for measuring angular velocity have been presented. In this paper,…

  15. Fat mass measured by DXA varies with scan velocity

    DEFF Research Database (Denmark)

    Black, Eva; Petersen, Liselotte; Kreutzer, Martin

    2002-01-01

    To study the influence of scan velocities of DXA on the measured size of fat mass, lean body mass, bone mineral content and density, and total body weight.......To study the influence of scan velocities of DXA on the measured size of fat mass, lean body mass, bone mineral content and density, and total body weight....

  16. Velocity-space sensitivity of neutron spectrometry measurements

    DEFF Research Database (Denmark)

    Jacobsen, Asger Schou; Salewski, Mirko; Eriksson, J.

    2015-01-01

    Neutron emission spectrometry (NES) measures the energies of neutrons produced in fusion reactions. Here we present velocity-space weight functions for NES and neutron yield measurements. Weight functions show the sensitivity as well as the accessible regions in velocity space for a given range...

  17. A comparative study of calculated and measured particle velocities

    International Nuclear Information System (INIS)

    Tariq, S.M.

    2005-01-01

    After an explosive is detonated in a blast hole, seismic waves are generated in the ground surrounding the blast hole. These waves cause the particles of rock to oscillate about its position. As the wave attenuate, the particles come back to their original position. The rapidity with which the particles move is called the particle velocity. The peak or maximum velocity is the value which is of prime concern. This value of peak particle velocity can be estimated by the equations determined by the United States Bureau of Mines and by the DUPONT. A research program was conducted by the author at the 'Beck Materials Quarry' situated near Rolla, Missouri, USA. The purpose was to draw a comparison between the predicted and measured particle velocities. It was generally found that the predicted peak particle velocities were quite high as compared to the velocities measured by the Seismographs. (author)

  18. Sound

    CERN Document Server

    Robertson, William C

    2003-01-01

    Muddled about what makes music? Stuck on the study of harmonics? Dumbfounded by how sound gets around? Now you no longer have to struggle to teach concepts you really don t grasp yourself. Sound takes an intentionally light touch to help out all those adults science teachers, parents wanting to help with homework, home-schoolers seeking necessary scientific background to teach middle school physics with confidence. The book introduces sound waves and uses that model to explain sound-related occurrences. Starting with the basics of what causes sound and how it travels, you'll learn how musical instruments work, how sound waves add and subtract, how the human ear works, and even why you can sound like a Munchkin when you inhale helium. Sound is the fourth book in the award-winning Stop Faking It! Series, published by NSTA Press. Like the other popular volumes, it is written by irreverent educator Bill Robertson, who offers this Sound recommendation: One of the coolest activities is whacking a spinning metal rod...

  19. Simultaneous sensing of light and sound velocities of fluids in a two-dimensional phoXonic crystal with defects

    Energy Technology Data Exchange (ETDEWEB)

    Amoudache, Samira [Institut d' Electronique, de Microélectronique et de Nanotechnologie, Université de Lille 1, 59655 Villeneuve d' Ascq (France); Laboratoire de Physique et Chimie Quantique, Université Mouloud Mammeri, B.P. 17 RP, 15000 Tizi-Ouzou (Algeria); Pennec, Yan, E-mail: yan.pennec@univ-lille1.fr; Djafari Rouhani, Bahram [Institut d' Electronique, de Microélectronique et de Nanotechnologie, Université de Lille 1, 59655 Villeneuve d' Ascq (France); Khater, Antoine [Institut des Molécules et Matériaux du Mans UMR 6283 CNRS, Université du Maine, 72085 Le Mans (France); Lucklum, Ralf [Institute of Micro and Sensor Systems (IMOS), Otto-von-Guericke-University, Magdeburg (Germany); Tigrine, Rachid [Laboratoire de Physique et Chimie Quantique, Université Mouloud Mammeri, B.P. 17 RP, 15000 Tizi-Ouzou (Algeria)

    2014-04-07

    We theoretically investigate the potentiality of dual phononic-photonic (the so-called phoxonic) crystals for liquid sensing applications. We study the transmission through a two-dimensional (2D) crystal made of infinite cylindrical holes in a silicon substrate, where one row of holes oriented perpendicular to the propagation direction is filled with a liquid. The infiltrated holes may have a different radius than the regular holes. We show, in the defect structure, the existence of well-defined features (peaks or dips) in the transmission spectra of acoustic and optical waves and estimate their sensitivity to the sound and light velocity of the analyte. Some of the geometrical requirements behave in opposite directions when searching for an efficient sensing of either sound or light velocities. Hence, a compromise in the choice of the parameters may become necessary in making the phoxonic sensor.

  20. Measuring surface current velocities in the Agulhas region with ASAR

    CSIR Research Space (South Africa)

    Rouault, MJ

    2010-01-01

    Full Text Available is known to perform well. Although radial velocities derived from ASAR are on occasion able to represent the measured flow with incredible accuracy, the overall performance of the ASAR radial velocity product is negatively impacted by a few very large...

  1. Measurement of gas flow velocities by laser-induced gratings

    Energy Technology Data Exchange (ETDEWEB)

    Hemmerling, B; Stampanoni-Panariello, A [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Kozlov, A D.N. [General Physics Institute, Moscow (Russian Federation)

    1999-08-01

    Time resolved light scattering from laser-induced electrostrictive gratings was used for the determination of flow velocities in air at room temperature. By measuring the velocity profile across the width of a slit nozzle we demonstrated the high spatial resolution (about 200 mm) of this novel technique. (author) 3 figs., 1 ref.

  2. Plasma flow velocity measurements using a modulated Michelson interferometer

    NARCIS (Netherlands)

    Howard, J.; Meijer, F. G.

    1997-01-01

    This paper discusses the possibility of flow velocity reconstruction using passive spectroscopic techniques. We report some preliminary measurements of the toroidal flow velocity of hydrogen atoms in the RTP tokamak using a phase modulated Michelson interferometer. (C) 1997 Elsevier Science S.A.

  3. A comparison of two different sound intensity measurement principles

    DEFF Research Database (Denmark)

    Jacobsen, Finn; de Bree, Hans-Elias

    2005-01-01

    , and compares the two measurement principles with particular regard to the sources of error in sound power determination. It is shown that the phase calibration of intensity probes that combine different transducers is very critical below 500 Hz if the measurement surface is very close to the source under test...

  4. Electron drift velocity measurements in liquid krypton-methane mixtures

    CERN Document Server

    Folegani, M; Magri, M; Piemontese, L

    1999-01-01

    Electron drift velocities have been measured in liquid krypton, pure and mixed with methane at different concentrations (1-10% in volume) versus electric field strength, and a possible effect of methane on electron lifetime has been investigated. While no effect on lifetime could be detected, since lifetimes were in all cases longer than what measurable, a very large increase in drift velocity (up to a factor 6) has been measured.

  5. Measurement of unsteady airflow velocity at nozzle outlet

    Science.gov (United States)

    Pyszko, René; Machů, Mário

    2017-09-01

    The paper deals with a method of measuring and evaluating the cooling air flow velocity at the outlet of the flat nozzle for cooling a rolled steel product. The selected properties of the Prandtl and Pitot sensing tubes were measured and compared. A Pitot tube was used for operational measurements of unsteady dynamic pressure of the air flowing from nozzles to abtain the flow velocity. The article also discusses the effects of air temperature, pressure and relative air humidity on air density, as well as the influence of dynamic pressure filtering on the error of averaged velocity.

  6. Measurement of particle velocity using a mutual inductance technique

    International Nuclear Information System (INIS)

    Kerr, Stephen; Kirkpatrick, Douglas; Garden, Steven

    2004-01-01

    Preliminary work on the development of a novel method for the measurement of particle velocity is described. The technique relies on measurement of the mutual inductance between two coaxial coils, one stationary and the other perturbed by the shock wave. The moving coil is the gauge and is deposited on thin film. The method was developed to assist in the study of particle velocities in large samples of porous media surrounding an explosive charge. The technique does not require measurements to be taken in a region of uniform magnetic field and therefore dispenses with the need for Helmholtz coils, the size and cost of which can become prohibitive for large experiments. This has the added advantage of allowing measurements to be taken at points widely dispersed through a sample with relative ease. Measurements of particle velocity in porous media have been compared with those from co-located conventional electromagnetic particle velocity gauges with reasonable agreement

  7. Doppler velocity measurements from large and small arteries of mice

    Science.gov (United States)

    Reddy, Anilkumar K.; Madala, Sridhar; Entman, Mark L.; Michael, Lloyd H.; Taffet, George E.

    2011-01-01

    With the growth of genetic engineering, mice have become increasingly common as models of human diseases, and this has stimulated the development of techniques to assess the murine cardiovascular system. Our group has developed nonimaging and dedicated Doppler techniques for measuring blood velocity in the large and small peripheral arteries of anesthetized mice. We translated technology originally designed for human vessels for use in smaller mouse vessels at higher heart rates by using higher ultrasonic frequencies, smaller transducers, and higher-speed signal processing. With these methods one can measure cardiac filling and ejection velocities, velocity pulse arrival times for determining pulse wave velocity, peripheral blood velocity and vessel wall motion waveforms, jet velocities for the calculation of the pressure drop across stenoses, and left main coronary velocity for the estimation of coronary flow reserve. These noninvasive methods are convenient and easy to apply, but care must be taken in interpreting measurements due to Doppler sample volume size and angle of incidence. Doppler methods have been used to characterize and evaluate numerous cardiovascular phenotypes in mice and have been particularly useful in evaluating the cardiac and vascular remodeling that occur following transverse aortic constriction. Although duplex ultrasonic echo-Doppler instruments are being applied to mice, dedicated Doppler systems are more suitable for some applications. The magnitudes and waveforms of blood velocities from both cardiac and peripheral sites are similar in mice and humans, such that much of what is learned using Doppler technology in mice may be translated back to humans. PMID:21572013

  8. Measuring surface flow velocity with smartphones: potential for citizen observatories

    Science.gov (United States)

    Weijs, Steven V.; Chen, Zichong; Brauchli, Tristan; Huwald, Hendrik

    2014-05-01

    Stream flow velocity is an important variable for discharge estimation and research on sediment dynamics. Given the influence of the latter on rating curves (stage-discharge relations), and the relative scarcity of direct streamflow measurements, surface velocity measurements can offer important information for, e.g., flood warning, hydropower, and hydrological science and engineering in general. With the growing amount of sensing and computing power in the hands of more outdoorsy individuals, and the advances in image processing techniques, there is now a tremendous potential to obtain hydrologically relevant data from motivated citizens. This is the main focus of the interdisciplinary "WeSenseIt" project, a citizen observatory of water. In this subproject, we investigate the feasibility of stream flow surface velocity measurements from movie clips taken by (smartphone-) cameras. First results from movie-clip derived velocity information will be shown and compared to reference measurements.

  9. Radar velocity determination using direction of arrival measurements

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W.; Bickel, Douglas L.; Naething, Richard M.; Horndt, Volker

    2017-12-19

    The various technologies presented herein relate to utilizing direction of arrival (DOA) data to determine various flight parameters for an aircraft A plurality of radar images (e.g., SAR images) can be analyzed to identify a plurality of pixels in the radar images relating to one or more ground targets. In an embodiment, the plurality of pixels can be selected based upon the pixels exceeding a SNR threshold. The DOA data in conjunction with a measurable Doppler frequency for each pixel can be obtained. Multi-aperture technology enables derivation of an independent measure of DOA to each pixel based on interferometric analysis. This independent measure of DOA enables decoupling of the aircraft velocity from the DOA in a range-Doppler map, thereby enabling determination of a radar velocity. The determined aircraft velocity can be utilized to update an onboard INS, and to keep it aligned, without the need for additional velocity-measuring instrumentation.

  10. Worldwide Echo-Sounding Correction Tables to Convert to Standard Velocity Depths

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Echo-sounding tables (3rd Edition) were prepared by D.J.T. Carter of the Marine Information and Advisory Service (United Kingdom) for the conversion of raw...

  11. Continuous measurements of in-bore projectile velocity

    International Nuclear Information System (INIS)

    Asay, J.R.; Konrad, C.H.; Hall, C.A.; Shahinpoor, M.

    1989-01-01

    The application of velocity interferometry to the continuous measurement of in-bore projectile velocity in a small-bore three-stage railgun is described. These measurements are useful for determining projectile acceleration and for evaluating gun performance. The launcher employed in these studies consists of a two-stage light gas gun used to inject projectiles into a railgun for additional acceleration. Results obtained for projectile velocities to 7.4 km/s with the two-stage injector are reported and potential improvements for railgun applications are discussed

  12. Method for measuring violin sound radiation based on bowed glissandi and its application to sound synthesis.

    Science.gov (United States)

    Perez Carrillo, Alfonso; Bonada, Jordi; Patynen, Jukka; Valimaki, Vesa

    2011-08-01

    This work presents a method for measuring and computing violin-body directional frequency responses, which are used for violin sound synthesis. The approach is based on a frame-weighted deconvolution of excitation and response signals. The excitation, consisting of bowed glissandi, is measured with piezoelectric transducers built into the bridge. Radiation responses are recorded in an anechoic chamber with multiple microphones placed at different angles around the violin. The proposed deconvolution algorithm computes impulse responses that, when convolved with any source signal (captured with the same transducer), produce a highly realistic violin sound very similar to that of a microphone recording. The use of motion sensors allows for tracking violin movements. Combining this information with the directional responses and using a dynamic convolution algorithm, helps to improve the listening experience by incorporating the violinist motion effect in stereo.

  13. Measurement of Poloidal Velocity on the National Spherical Torus Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ronald E. Bell and Russell Feder

    2010-06-04

    A diagnostic suite has been developed to measure impurity poloidal flow using charge exchange recombination spectroscopy on the National Spherical Torus Experiment. Toroidal and poloidal viewing systems measure all quantities required to determine the radial electric field. Two sets of up/down symmetric poloidal views are used to measure both active emission in the plane of the neutral heating beams and background emission in a radial plane away from the neutral beams. Differential velocity measurements isolate the line-integrated poloidal velocity from apparent flows due to the energy-dependent chargeexchange cross section. Six f/1.8 spectrometers measure 276 spectra to obtain 75 active and 63 background channels every 10 ms. Local measurements from a similar midplane toroidal viewing system are mapped into two dimensions to allow the inversion of poloidal line-integrated measurements to obtain local poloidal velocity profiles. Radial resolution after inversion is 0.6-1.8 cm from the plasma edge to the center.

  14. Measurement of Poloidal Velocity on the National Spherical Torus Experiment

    International Nuclear Information System (INIS)

    Bell, Ronald E.; Feder, Russell

    2010-01-01

    A diagnostic suite has been developed to measure impurity poloidal flow using charge exchange recombination spectroscopy on the National Spherical Torus Experiment. Toroidal and poloidal viewing systems measure all quantities required to determine the radial electric field. Two sets of up/down symmetric poloidal views are used to measure both active emission in the plane of the neutral heating beams and background emission in a radial plane away from the neutral beams. Differential velocity measurements isolate the line-integrated poloidal velocity from apparent flows due to the energy-dependent chargeexchange cross section. Six f/1.8 spectrometers measure 276 spectra to obtain 75 active and 63 background channels every 10 ms. Local measurements from a similar midplane toroidal viewing system are mapped into two dimensions to allow the inversion of poloidal line-integrated measurements to obtain local poloidal velocity profiles. Radial resolution after inversion is 0.6-1.8 cm from the plasma edge to the center.

  15. Cerenkov detector for heavy-ion velocity measurements

    International Nuclear Information System (INIS)

    Olson, D.L.; Baumgartner, M.; Dufour, J.P.; Girard, J.G.; Greiner, D.E.; Lindstrom, P.J.; Symons, T.J.M.; Crawford, H.J.

    1984-08-01

    We have developed a highly sensitive velocity measuring detector using total-internal-reflection Cerenkov counters of a type mentioned by Jelly in 1958. If the velocity of the particle is above the threshold for total-internal-reflection these counters have a charge resolution of sigma = 0.18e for a 3mm thick glass radiator. For the velocity measurement we use a fused silica radiator so that the velocity of the particles are near the threshold for total-internal reflection. For momentum-analyzed projectile fragments of 1.6 GeV/nucleon 40 Ar, we have measured a mass resolution of sigma = 0.1u for isotope identification

  16. Ice sheet anisotropy measured with polarimetric ice sounding radar

    DEFF Research Database (Denmark)

    Dall, Jørgen

    2010-01-01

    For polar ice sheets, valuable stress and strain information can be deduced from crystal orientation fabrics (COF) and their prevailing c-axis alignment. Polarimetric radio echo sounding is a promising technique to measure the anisotropic electromagnetic propagation and reflection properties asso...

  17. Indoor measurements of sound at low frequencies

    DEFF Research Database (Denmark)

    Pedersen, Steffen; Møller, Henrik; Persson-Waye, Kerstin

    2006-01-01

    Due to standing waves, the sound pressure level within a room may vary as much as 20-30 dB with low-frequency tonal noise, somewhat less with noise bands. For assessment of annoyance from low-frequency noise it is relevant to measure a level close to the highest level of the room, rather than a r...

  18. SOUND VELOCITY and Other Data from FIXED PLATFORM and Other Platforms From NE Atlantic (limit-40 W) and Others from 19860512 to 19891112 (NODC Accession 9000121)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The sound velocity and other data in this accession has been processed by NODC from a tape submitted by the originator containing Inverted Echo Sounder data from the...

  19. Salinity, sound velocity, and other data from CTD, XBT, XSV, AXBT, and XCTD casts from 20 May 1978 to 01 September 2000 (NODC Accession 0000383)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Salinity, sound velocity, depth, and temperature data were collected using CTD, XBT, XSV, AXBT, and XCTD casts from May 20, 1978 to September 1, 2000. Data were...

  20. Sound velocity profiles collected by NOAA's Navigation Response Team No. 4 in the Great Lakes, July 5 - September 25, 2007 (NODC Accession 0020370)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical oceanographic data were collected from NOAA Navigation Response Team-4 in the Great Lakes from 05 July 2007 to 25 September 2007. Sound velocity profiles...

  1. Burning velocity measurements of nitrogen-containing compounds.

    Science.gov (United States)

    Takizawa, Kenji; Takahashi, Akifumi; Tokuhashi, Kazuaki; Kondo, Shigeo; Sekiya, Akira

    2008-06-30

    Burning velocity measurements of nitrogen-containing compounds, i.e., ammonia (NH3), methylamine (CH3NH2), ethylamine (C2H5NH2), and propylamine (C3H7NH2), were carried out to assess the flammability of potential natural refrigerants. The spherical-vessel (SV) method was used to measure the burning velocity over a wide range of sample and air concentrations. In addition, flame propagation was directly observed by the schlieren photography method, which showed that the spherical flame model was applicable to flames with a burning velocity higher than approximately 5 cm s(-1). For CH3NH2, the nozzle burner method was also used to confirm the validity of the results obtained by closed vessel methods. We obtained maximum burning velocities (Su0,max) of 7.2, 24.7, 26.9, and 28.3 cm s(-1) for NH3, CH3NH2, C2H5NH2, and C3H7NH2, respectively. It was noted that the burning velocities of NH3 and CH3NH2 were as high as those of the typical hydrofluorocarbon refrigerants difluoromethane (HFC-32, Su0,max=6.7 cm s(-1)) and 1,1-difluoroethane (HFC-152a, Su0,max=23.6 cm s(-1)), respectively. The burning velocities were compared with those of the parent alkanes, and it was found that introducing an NH2 group into hydrocarbon molecules decreases their burning velocity.

  2. Time-dependent coolant velocity measurements in an operating BWR

    International Nuclear Information System (INIS)

    Luebbesmeyer, D.; Crowe, R.D.

    1980-01-01

    A method to measure time-dependent fluid velocities in BWR-bundle elements by noise analysis of the incore-neutron-detector signals is shown. Two application examples of the new method are given. The time behaviour of the fluid velocity in the bundle element during a scheduled power excursion of the plant. The change of power was performed by changing the coolant flow through the core The apparent change of the fluid velocity due to thermal elongation of the helix-drive of the TIP-system. A simplified mathematical model was derived for this elongation to use as a reference to check the validity of the new method. (author)

  3. A Method of Initial Velocity Measurement for Rocket Projectile

    Directory of Open Access Journals (Sweden)

    Zhang Jiancheng

    2017-01-01

    Full Text Available In this paper, a novel method is proposed to measure the initial velocity of the rocket based on STFT (the short-time Fourier transform and the WT (wavelet transform. The radar echo signal processing procedure involves the following steps: sampling process, overlapping windows, wavelet decomposition and reconstruction, computing FFT (Fast Fourier Transform and spectrum analysis, power spectrum peak detection. Then, according to the peak of the detection power spectrum, the corresponding Doppler frequency is obtained. Finally, on the basis of the relationship between Doppler frequency and instantaneous velocity, the V-T curve is drawn in MATLAB to obtain the initial velocity of the rocket muzzle.

  4. A mixing method for traceable air velocity measurements

    International Nuclear Information System (INIS)

    Sillanpää, S; Heinonen, M

    2008-01-01

    A novel and quite simple method to establish a traceability link between air velocity and the national standards of mass and time is presented in this paper. The method is based on the humidification of flowing air before the blower of a wind tunnel with a known mass flow of water. Then air velocity can be calculated as a function of humidification water flow. The method is compared against a Pitot-tube-based velocity measurement in a wind tunnel at the MIKES. The results of these two different methods agreed well, with a maximum difference of 0.7%

  5. Measurement bias of fluid velocity in molecular simulations

    International Nuclear Information System (INIS)

    Tysanner, Martin W.; Garcia, Alejandro L.

    2004-01-01

    In molecular simulations of fluid flow, the measurement of mean fluid velocity is considered to be a straightforward computation, yet there is some ambiguity in its definition. We show that in systems far from equilibrium, such as those with large temperature or velocity gradients, two commonly used definitions give slightly different results. Specifically, a bias can arise when computing the mean fluid velocity by measuring the mean particle velocity in a cell and averaging this mean over samples. We show that this bias comes from the correlation of momentum and density fluctuations in non-equilibrium fluids, obtain an analytical expression for predicting it, and discuss what system characteristics (e.g., number of particles per cell, temperature gradients) reduce or magnify the error. The bias has a physical origin so although we demonstrate it by direct simulation Monte Carlo (DSMC) computations, the same effect will be observed with other particle-based simulation methods, such as molecular dynamics and lattice gases

  6. Measurements of electron drift velocity in pure isobutane

    Energy Technology Data Exchange (ETDEWEB)

    Vivaldini, Tulio C.; Lima, Iara B.; Goncalves, Josemary A.C.; Botelho, Suzana; Tobias, Carmen C.B., E-mail: ccbueno@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ridenti, Marco A.; Pascholati, Paulo R. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Fisica. Lab. do Acelerador Linear; Fonte, Paulo; Mangiarotti, Alessio [Universidade de Coimbra (Portugal). Dept de Fisica. Lab. de Instrumentacao e Fisica Experimental de Particulas

    2009-07-01

    In this work we report on preliminary results related to the dependence of the electron drift velocity for pure isobutane as a function of reduced electric field (E/N) in the range from 100 Td up to 216 Td. The measurements of electron drift velocity were based on the Pulsed Townsend technique. In order to validate the technique and analyzing non-uniformity effects, results for nitrogen are also presented and compared with a numerical simulation of the Bolsig+ code. (author)

  7. Measurements of electron drift velocity in pure isobutane

    International Nuclear Information System (INIS)

    Vivaldini, Tulio C.; Lima, Iara B.; Goncalves, Josemary A.C.; Botelho, Suzana; Tobias, Carmen C.B.; Ridenti, Marco A.; Pascholati, Paulo R.; Fonte, Paulo; Mangiarotti, Alessio

    2009-01-01

    In this work we report on preliminary results related to the dependence of the electron drift velocity for pure isobutane as a function of reduced electric field (E/N) in the range from 100 Td up to 216 Td. The measurements of electron drift velocity were based on the Pulsed Townsend technique. In order to validate the technique and analyzing non-uniformity effects, results for nitrogen are also presented and compared with a numerical simulation of the Bolsig+ code. (author)

  8. Free-surface velocity measurements using an optically recording velocity interferometer

    International Nuclear Information System (INIS)

    Lu Jianxin; Wang Zhao; Liang Jing; Shan Yusheng; Zhou Chuangzhi; Xiang Yihuai; Lu Ze; Tang Xiuzhang

    2006-01-01

    An optically recording velocity interferometer system (ORVIS) was developed for the free-surface velocity measurements in the equation of state experiments. The time history of free-surface velocity could be recorded by the electronic streak camera. In the experiments, ORVIS got a 179 ps time resolution, and a higher time resolution could be got by minimizing the delay time. The equation of state experiments were carried out on the high power excimer laser system called 'Heaven I' with laser wavelength of 248.4 nm, pulse duration of 25 ns and maximum energy 158 J. Free-surface velocity of 20 μm thick iron got 3.86 km/s with laser intensity of 6.24 x 10 11 W·cm -2 , and free-surface velocity of 100 μm thick aluminum with 100 μm CH foil at the front got 2.87 km/s with laser intensity 7.28 x 10 11 W·cm -2 . (authors)

  9. Sound at the zoo: Using animal monitoring, sound measurement, and noise reduction in zoo animal management.

    Science.gov (United States)

    Orban, David A; Soltis, Joseph; Perkins, Lori; Mellen, Jill D

    2017-05-01

    A clear need for evidence-based animal management in zoos and aquariums has been expressed by industry leaders. Here, we show how individual animal welfare monitoring can be combined with measurement of environmental conditions to inform science-based animal management decisions. Over the last several years, Disney's Animal Kingdom® has been undergoing significant construction and exhibit renovation, warranting institution-wide animal welfare monitoring. Animal care and science staff developed a model that tracked animal keepers' daily assessments of an animal's physical health, behavior, and responses to husbandry activity; these data were matched to different external stimuli and environmental conditions, including sound levels. A case study of a female giant anteater and her environment is presented to illustrate how this process worked. Associated with this case, several sound-reducing barriers were tested for efficacy in mitigating sound. Integrating daily animal welfare assessment with environmental monitoring can lead to a better understanding of animals and their sensory environment and positively impact animal welfare. © 2017 Wiley Periodicals, Inc.

  10. Experimental investigation of the temperature dependence of sound velocity in the structural materials for nuclear power engineering

    International Nuclear Information System (INIS)

    Roshchupkin, V.V.; Pokrasin, M.A.; Chernov, A.I.; Semashko, N.A.; Filonenko, S.F.

    1999-01-01

    The purpose of the study consists in determination of the sound velocity temperature dependence in structural materials for nuclear power engineering. In particular, the Zr-2.5%Nb, Hastelloys-H alloys and X2.5M steel are studied. The facility for studying acoustic parameters of metals and alloys is described. The software makes it possible to obtain the results in various forms with the data stored in the memory for further analysis. The data on the above alloys obtained by use of various methods are presented and analyzed [ru

  11. Measuring average angular velocity with a smartphone magnetic field sensor

    Science.gov (United States)

    Pili, Unofre; Violanda, Renante

    2018-02-01

    The angular velocity of a spinning object is, by standard, measured using a device called a tachometer. However, by directly using it in a classroom setting, the activity is likely to appear as less instructive and less engaging. Indeed, some alternative classroom-suitable methods for measuring angular velocity have been presented. In this paper, we present a further alternative that is smartphone-based, making use of the real-time magnetic field (simply called B-field in what follows) data gathering capability of the B-field sensor of the smartphone device as the timer for measuring average rotational period and average angular velocity. The in-built B-field sensor in smartphones has already found a number of uses in undergraduate experimental physics. For instance, in elementary electrodynamics, it has been used to explore the well-known Bio-Savart law and in a measurement of the permeability of air.

  12. Acoustic holography for piston sound radiation with non-uniform velocity profiles

    NARCIS (Netherlands)

    Aarts, R.M.; Janssen, A.J.E.M.

    2010-01-01

    The theory of orthogonal (Zernike) expansions of functions on a disk, as used in the diffraction theory of optical aberrations, is applied to obtain (semi-) analytical results for the radiation of sound due to a non-uniformly moving, baffled, circular piston. For this particular case, a scheme for

  13. Measurement of LBE flow velocity profile by UDVP

    International Nuclear Information System (INIS)

    Kikuchi, Kenji; Takeda, Yasushi; Obayashi, Hiroo; Tezuka, Masao; Sato, Hiroshi

    2006-01-01

    Measurements of liquid metal lead-bismuth eutectic (LBE), flow velocity profile were realized in the spallation neutron source target model by the ultrasonic Doppler velocity profiler (UVDP) technique. So far, it has not been done well, because both of poor wetting property of LBE with stainless steels and poor performance of supersonic probes at high temperatures. The measurement was made for a return flow in the target model, which has coaxially arranged annular and tube channels, in the JAEA Lead Bismuth Loop-2 (JLBL-2). The surface treatment of LBE container was examined. It was found that the solder coating was effective to enhance an intensity of reflected ultrasonic wave. This treatment has been applied to the LBE loop, which was operated up to 150 deg. C. The electro magnetic pump generates LBE flow and the flow rate was measured by the electro magnetic flow meter. By changing the flow rate of LBE, velocity profiles in the target were measured. It was confirmed that the maximum velocity in the time-averaged velocity distribution on the target axis was proportional to the flow rate measured by the electro magnetic flow meter

  14. On the measurements of large scale solar velocity fields

    International Nuclear Information System (INIS)

    Andersen, B.N.

    1985-01-01

    A general mathematical formulation for the correction of the scattered light influence on solar Doppler shift measurements has been developed. This method has been applied to the straylight correction of measurements of solar rotation, limb effect, large scale flows and oscillations. It is shown that neglecting the straylight errors may cause spurious large scale velocity fields, oscillations and erronous values for the solar rotation and limb effect. The influence of active regions on full disc velocity measurements has been studied. It is shown that a 13 day periodicity in the global velocity signal will be introduced by the passage of sunspots over the solar disc. With different types of low resolution apertures, other periodicities may be introduced. Accurate measurements of the center-to-limb velocity shift are presented for a set of magnetic insensitive lines well suited for solar velocity measurements. The absolute wavelenght shifts are briefly discussed. The stronger lines have a ''supergravitational'' shift of 300-400 m/s at the solar limb. The results may be explained by the presence of a 20-25 m/s poleward meridional flow and a latitudinal dependence of the granular parameters. Using a simple model it is shown that the main properites of the observations are explained by a 5% increase in the granular size with latitude. Data presented indicate that the resonance line K I, 769.9 nm has a small but significant limb effect of 125 m/s from center to limb

  15. Using embedded fibers to measure explosive detonation velocities

    Energy Technology Data Exchange (ETDEWEB)

    Podsednik, Jason W.; Parks, Shawn Michael; Navarro, Rudolfo J.

    2012-07-01

    Single-mode fibers were cleverly embedded into fixtures holding nitromethane, and used in conjunction with a photonic Doppler velocimeter (PDV) to measure the associated detonation velocity. These measurements have aided us in our understanding of energetic materials and enhanced our diagnostic capabilities.

  16. Estimating Radar Velocity using Direction of Arrival Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Horndt, Volker [General Atomics Aeronautical Systems, Inc., San Diego, CA (United States); Bickel, Douglas Lloyd [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Naething, Richard M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    Direction of Arrival (DOA) measurements, as with a monopulse antenna, can be compared against Doppler measurements in a Synthetic Aperture Radar ( SAR ) image to determine an aircraft's forward velocity as well as its crab angle, to assist the aircraft's navigation as well as improving high - performance SAR image formation and spatial calibration.

  17. Measurement of the neutrino velocity in OPERA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Dracos, M., E-mail: marcos.dracos@in2p3.fr [IPHC, Université de Strasbourg, CNRS/IN2P3, F-67037 Strasbourg (France)

    2013-02-15

    The OPERA neutrino experiment has measured the neutrino velocity using the CERN CNGS beam over a baseline of 730 km. The measurement is based on data taken by OPERA in the years 2009, 2010, 2011. An arrival time of CNGS muon neutrinos with respect to the one computed assuming the speed of light in vacuum of (6.5±7.4(stat.){sub −8.0}{sup +8.3}(sys.))ns was measured corresponding to a relative difference of the muon neutrino velocity with respect to the speed of light (v−c)/c=(2.7±3.1(stat.){sub −3.3}{sup +3.4}(sys.))×10{sup −6}. During spring 2012 the CNGS provided during two weeks a short proton bunched beam dedicated to the neutrino velocity measurement. The OPERA neutrino experiment at the underground Gran Sasso Laboratory has measured the velocity of neutrinos with slightly modified setup compared to 2011 measurements. These modifications increased the timing accuracy and also fixed previous problems. The arrival time of CNGS muon neutrinos with respect to the one computed assuming the speed of light in vacuum has been found to be in agreement with the previous measurement. This result confirms the revised OPERA result and that indeed the neutrino anticipation announced in September 2011 was due to technical problems.

  18. Optic-microwave mixing velocimeter for superhigh velocity measurement

    International Nuclear Information System (INIS)

    Weng Jidong; Wang Xiang; Tao Tianjiong; Liu Cangli; Tan Hua

    2011-01-01

    The phenomenon that a light beam reflected off a moving object experiences a Doppler shift in its frequency underlies practical interferometric techniques for remote velocity measurements, such as velocity interferometer system for any reflector (VISAR), displacement interferometer system for any reflector (DISAR), and photonic Doppler velocimetry (PDV). While VISAR velocimeters are often bewildered by the fringe loss upon high-acceleration dynamic process diagnosis, the optic-fiber velocimeters such as DISAR and PDV, on the other hand, are puzzled by high velocity measurement over 10 km/s, due to the demand for the high bandwidth digitizer. Here, we describe a new optic-microwave mixing velocimeter (OMV) for super-high velocity measurements. By using currently available commercial microwave products, we have constructed a simple, compact, and reliable OMV device, and have successfully obtained, with a digitizer of bandwidth 6 GH only, the precise velocity history of an aluminum flyer plate being accelerated up to 11.2 km/s in a three stage gas-gun experiment.

  19. Illumination Profile & Dispersion Variation Effects on Radial Velocity Measurements

    Science.gov (United States)

    Grieves, Nolan; Ge, Jian; Thomas, Neil B.; Ma, Bo; Li, Rui; SDSS-III

    2015-01-01

    The Multi-object APO Radial-Velocity Exoplanet Large-Area Survey (MARVELS) measures radial velocities using a fiber-fed dispersed fixed-delay interferometer (DFDI) with a moderate dispersion spectrograph. This setup allows a unique insight into the 2D illumination profile from the fiber on to the dispersion grating. Illumination profile investigations show large changes in the profile over time and fiber location. These profile changes are correlated with dispersion changes and long-term radial velocity offsets, a major problem within the MARVELS radial velocity data. Characterizing illumination profiles creates a method to both detect and correct radial velocity offsets, allowing for better planet detection. Here we report our early results from this study including improvement of radial velocity data points from detected giant planet candidates. We also report an illumination profile experiment conducted at the Kitt Peak National Observatory using the EXPERT instrument, which has a DFDI mode similar to MARVELS. Using profile controlling octagonal-shaped fibers, long term offsets over a 3 month time period were reduced from ~50 m/s to within the photon limit of ~4 m/s.

  20. Hemodynamic study of ischemic limb by velocity measurement in foot

    International Nuclear Information System (INIS)

    Shionoya, S.; Hirai, M.; Kawai, S.; Ohta, T.; Seko, T.

    1981-01-01

    By means of a tracer technique with 99mTc-pertechnetate, provided with seven zonal regions of interest, 6 mm in width, placed at equal spaces of 18 mm, from the toe tip to the midfoot at a right angle to the long axis of the foot, arterial flow velocity in the foot during reactive hyperemia was measured. The mean velocity in the foot was 5.66 +/- 1.78 cm/sec in 14 normal limbs, 1.58 +/- 1.07 cm/sec in 29 limbs with distal thromboangiitis obliterans (TAO), 0.89 +/- 0.61 cm/sec in 13 limbs with proximal TAO, and 0.97 +/- 0.85 cm/sec in 15 limbs with arteriosclerosis obliterans (ASO). The velocity returned to normal in all 12 limbs after successful arterial reconstruction, whereas the foot or toe blood pressure remained pathologic in 9 of the 12 limbs postoperatively; the velocity reverted to normal in 4 of 13 limbs after lumbar sympathectomy. When the velocity was normalized after operation, the ulceration healed favorably, and the ischemic limb was salvaged. The most characteristic feature of peripheral arterial occlusive disease of the lower extremity was a stagnation of arterial circulation in the foot, and the flow velocity in the foot was a sensitive predictive index of limb salvage

  1. Velocity and rotation measurements in acoustically levitated droplets

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Abhishek [University of Central Florida, Orlando, FL 32816 (United States); Basu, Saptarshi [Indian Institute of Science, Bangalore 560012 (India); Kumar, Ranganathan, E-mail: ranganathan.kumar@ucf.edu [University of Central Florida, Orlando, FL 32816 (United States)

    2012-10-01

    The velocity scale inside an acoustically levitated droplet depends on the levitator and liquid properties. Using Particle Imaging Velocimetry (PIV), detailed velocity measurements have been made in a levitated droplet of different diameters and viscosity. The maximum velocity and rotation are normalized using frequency and amplitude of acoustic levitator, and droplet viscosity. The non-dimensional data are fitted for micrometer- and millimeter-sized droplets levitated in different levitators for different viscosity fluids. It is also shown that the rotational speed of nanosilica droplets at an advanced stage of vaporization compares well with that predicted by exponentially fitted parameters. -- Highlights: ► Demonstrates the importance of rotation in a levitated droplet that leads to controlled morphology. ► Provides detailed measurements of Particle Image Velocimetry inside levitated droplets. ► Shows variation of vortex strength with the droplet diameter and viscosity of the liquid.

  2. Velocity and rotation measurements in acoustically levitated droplets

    International Nuclear Information System (INIS)

    Saha, Abhishek; Basu, Saptarshi; Kumar, Ranganathan

    2012-01-01

    The velocity scale inside an acoustically levitated droplet depends on the levitator and liquid properties. Using Particle Imaging Velocimetry (PIV), detailed velocity measurements have been made in a levitated droplet of different diameters and viscosity. The maximum velocity and rotation are normalized using frequency and amplitude of acoustic levitator, and droplet viscosity. The non-dimensional data are fitted for micrometer- and millimeter-sized droplets levitated in different levitators for different viscosity fluids. It is also shown that the rotational speed of nanosilica droplets at an advanced stage of vaporization compares well with that predicted by exponentially fitted parameters. -- Highlights: ► Demonstrates the importance of rotation in a levitated droplet that leads to controlled morphology. ► Provides detailed measurements of Particle Image Velocimetry inside levitated droplets. ► Shows variation of vortex strength with the droplet diameter and viscosity of the liquid.

  3. Optical-fiber interferometer for velocity measurements with picosecond resolution

    International Nuclear Information System (INIS)

    Weng Jidong; Tan Hua; Wang Xiang; Ma Yun; Hu Shaolou; Wang Xiaosong

    2006-01-01

    The conventional Doppler laser-interference velocimeters are made up of traditional optical elements such as lenses and mirrors and will generally restrict its applications in multipoint velocity measurements. By transfering the light from multimode optical fiber to single-mode optical fiber and using the currently available conventional telecommunications elements, the authors have constructed a velocimeter called all-fiber displacement interferometer system for any reflector. The unique interferometer system is only made up of fibers or fiber-coupled components. The viability of this technique is demonstrated by measuring the velocity of an interface moving at velocity of 2133 m/s with 50 ps time resolution. In addition, the concept of optical-fiber mode conversion would provide a way to develop various optical-fiber sensors

  4. Coherence measures in automatic time-migration velocity analysis

    International Nuclear Information System (INIS)

    Maciel, Jonathas S; Costa, Jessé C; Schleicher, Jörg

    2012-01-01

    Time-migration velocity analysis can be carried out automatically by evaluating the coherence of migrated seismic events in common-image gathers (CIGs). The performance of gradient methods for automatic time-migration velocity analysis depends on the coherence measures used as the objective function. We compare the results of four different coherence measures, being conventional semblance, differential semblance, an extended differential semblance using differences of more distant image traces and the product of the latter with conventional semblance. In our numerical experiments, the objective functions based on conventional semblance and on the product of conventional semblance with extended differential semblance provided the best velocity models, as evaluated by the flatness of the resulting CIGs. The method can be easily extended to anisotropic media. (paper)

  5. Repeatability and reproducibility of in situ measurements of sound reflection and airborne sound insulation index of noise barriers

    NARCIS (Netherlands)

    Garai, M.; Schoen, E.; Behler, G.; Bragado, B.; Chudalla, M.; Conter, M.; Defrance, J.; Demizieux, P.; Glorieux, C.; Guidorzi, P.

    2014-01-01

    In Europe, in situ measurements of sound reflection and airborne sound insulation of noise barriers are usually done according to CEN/TS 1793-5. This method has been improved substantially during the EU funded QUIESST collaborative project. Within the same framework, an inter-laboratory test has

  6. Characterization of the natural ambient sound environment : Measurements in open agricultural grassland

    NARCIS (Netherlands)

    Boersma, HF

    The audibility of manmade sound in a natural environment is affected because of masking by ambient sound. In this report results are presented of measurements of the level and spectral composition of natural ambient sound. The statistical L-95 level was determined, i.e., the sound pressure level

  7. Poloidal rotation velocity measurement in toroidal plasmas via microwave reflectometry

    International Nuclear Information System (INIS)

    Pavlichenko, O.S.; Skibenko, A.I.; Fomin, I.P.; Pinos, I.B.; Ocheretenko, V.L.; Berezhniy, V.L.

    2001-01-01

    Results of experiment modeling backscattering of microwaves from rotating plasma layer perturbed by fluctuations are presented. It was shown that auto- and crosscorrelation of reflected power have a periodicity equal to rotation period. Such periodicity was observed by microwave reflectometry in experiments on RF plasma production on U-3M torsatron and was used for measurement of plasma poloidal rotation velocity. (author)

  8. A sound and efficient measure of joint congruence.

    Science.gov (United States)

    Conconi, Michele; Castelli, Vincenzo Parenti

    2014-09-01

    In the medical world, the term "congruence" is used to describe by visual inspection how the articular surfaces mate each other, evaluating the joint capability to distribute an applied load from a purely geometrical perspective. Congruence is commonly employed for assessing articular physiology and for the comparison between normal and pathological states. A measure of it would thus represent a valuable clinical tool. Several approaches for the quantification of joint congruence have been proposed in the biomechanical literature, differing on how the articular contact is modeled. This makes it difficult to compare different measures. In particular, in previous articles a congruence measure has been presented which proved to be efficient and suitable for the clinical practice, but it was still empirically defined. This article aims at providing a sound theoretical support to this congruence measure by means of the Winkler elastic foundation contact model which, with respect to others, has the advantage to hold also for highly conforming surfaces as most of the human articulations are. First, the geometrical relation between the applied load and the resulting peak of pressure is analytically derived from the elastic foundation contact model, providing a theoretically sound approach to the definition of a congruence measure. Then, the capability of congruence measure to capture the same geometrical relation is shown. Finally, the reliability of congruence measure is discussed. © IMechE 2014.

  9. MEASURING EJECTA VELOCITY IMPROVES TYPE Ia SUPERNOVA DISTANCES

    International Nuclear Information System (INIS)

    Foley, Ryan J.; Kasen, Daniel

    2011-01-01

    We use a sample of 121 spectroscopically normal Type Ia supernovae (SNe Ia) to show that their intrinsic color is correlated with their ejecta velocity, as measured from the blueshift of the Si II λ6355 feature near maximum brightness, v SiII . The SN Ia sample was originally used by Wang et al. to show that the relationship between color excess and peak magnitude, which in the absence of intrinsic color differences describes a reddening law, was different for two subsamples split by v SiII (defined as 'Normal' and 'High Velocity'). We verify this result, but find that the two subsamples have the same reddening law when extremely reddened events (E(B - V)>0.35 mag) are excluded. We also show that (1) the High-Velocity subsample is offset by ∼0.06 mag to the red from the Normal subsample in the (B max - V max )-M V plane, (2) the B max - V max cumulative distribution functions of the two subsamples have nearly identical shapes, but the High-Velocity subsample is offset by ∼0.07 mag to the red in B max - V max , and (3) the bluest High-Velocity SNe Ia are ∼0.10 mag redder than the bluest Normal SNe Ia. Together, this evidence indicates a difference in intrinsic color for the subsamples. Accounting for this intrinsic color difference reduces the scatter in Hubble residuals from 0.190 mag to 0.130 mag for SNe Ia with A V ∼ V found in large SN Ia samples. We explain the correlation between ejecta velocity and color as increased line blanketing in the High-Velocity SNe Ia, causing them to become redder. We discuss some implications of this result, and stress the importance of spectroscopy for future SN Ia cosmology surveys, with particular focus on the design of WFIRST.

  10. An inexpensive instrument for measuring wave exposure and water velocity

    Science.gov (United States)

    Figurski, J.D.; Malone, D.; Lacy, J.R.; Denny, M.

    2011-01-01

    Ocean waves drive a wide variety of nearshore physical processes, structuring entire ecosystems through their direct and indirect effects on the settlement, behavior, and survivorship of marine organisms. However, wave exposure remains difficult and expensive to measure. Here, we report on an inexpensive and easily constructed instrument for measuring wave-induced water velocities. The underwater relative swell kinetics instrument (URSKI) is a subsurface float tethered by a short (<1 m) line to the seafloor. Contained within the float is an accelerometer that records the tilt of the float in response to passing waves. During two field trials totaling 358 h, we confirmed the accuracy and precision of URSKI measurements through comparison to velocities measured by an in situ acoustic Doppler velocimeter and those predicted by a standard swell model, and we evaluated how the dimensions of the devices, its buoyancy, and sampling frequency can be modified for use in a variety of environments.

  11. Extraction of Poloidal Velocity from Charge Exchange Recombination Spectroscopy Measurements

    International Nuclear Information System (INIS)

    Solomon, W.M.; Burrell, K.H.; Gohil, P.; Groebner, R.J.; Baylor, L.R.

    2004-01-01

    A novel approach has been implemented on DIII-D to allow the correct determination of the plasma poloidal velocity from charge exchange spectroscopy measurements. Unlike usual techniques, the need for detailed atomic physics calculations to properly interpret the results is alleviated. Instead, the needed atomic physics corrections are self-consistently determined directly from the measurements, by making use of specially chosen viewing chords. Modeling results are presented that were used to determine a set of views capable of measuring the correction terms. We present the analysis of a quiescent H-mode discharge, illustrating that significant modifications to the velocity profiles are required in these high ion temperature conditions. We also present preliminary measurements providing the first direct comparison of the standard cross-section correction to the atomic physics calculations

  12. Testing measurements of airflow velocity in road tunnels

    Directory of Open Access Journals (Sweden)

    Danišovič Peter

    2017-01-01

    Full Text Available Within the project entitled “Models of formation and spread of fire to increase safety of road tunnels”, it was necessary to devise a method how to record airflow velocity during the fire in situ tests in road tunnels. Project is in first year of its solution so one testing measurement was performed to check the functionality of anemometers selected for this project and the first in situ measurement was also performed just a few days ago.

  13. An asymptotic inversion method of inferring the sound velocity distribution in the sun from the spectrum of p-mode oscillations

    International Nuclear Information System (INIS)

    Sekii, Takashi; Shibahashi, Hiromoto

    1989-01-01

    We present an inversion method of inferring the sound velocity distribution in the Sun from its oscillation data of p-modes. The equation governing the p-mode oscillations is reduced to a form similar to the Schroedinger equation in quantum mechanics. By using a quantization rule based on the KWBJ asymptotic method, we derive an integral equation of which solution provides the 'acoustic potential' of the wave equation. The acoustic potential consists of two parts: One of them is related with the squared sound velocity and is dependent on the degree of the mode l, while the other term is independent of l and dominates in the outer part of the Sun. By examining the l-dependence of the acoustic potential obtained as the solution of the integral equation, we separate these two components of the potential and eventually obtain the sound velocity distribution from a set of eigenfrequencies of p-modes. In order to evaluate prospects of this inversion method, we perform numerical simulations in which eigenfrequencies of a theoretical solar model are used to reproduce the sound velocity distribution of the model. The error of thus inferred sound velocity relative to the true values is estimated to be less than a few percent. (author)

  14. Velocity measurement accuracy in optical microhemodynamics: experiment and simulation

    International Nuclear Information System (INIS)

    Chayer, Boris; Cloutier, Guy; L Pitts, Katie; Fenech, Marianne

    2012-01-01

    Micro particle image velocimetry (µPIV) is a common method to assess flow behavior in blood microvessels in vitro as well as in vivo. The use of red blood cells (RBCs) as tracer particles, as generally considered in vivo, creates a large depth of correlation (DOC), even as large as the vessel itself, which decreases the accuracy of the method. The limitations of µPIV for blood flow measurements based on RBC tracking still have to be evaluated. In this study, in vitro and in silico models were used to understand the effect of the DOC on blood flow measurements using µPIV RBC tracer particles. We therefore employed a µPIV technique to assess blood flow in a 15 µm radius glass tube with a high-speed CMOS camera. The tube was perfused with a sample of 40% hematocrit blood. The flow measured by a cross-correlating speckle tracking technique was compared to the flow rate of the pump. In addition, a three-dimensional mechanical RBC-flow model was used to simulate optical moving speckle at 20% and 40% hematocrits, in 15 and 20 µm radius circular tubes, at different focus planes, flow rates and for various velocity profile shapes. The velocity profiles extracted from the simulated pictures were compared with good agreement with the corresponding velocity profiles implemented in the mechanical model. The flow rates from both the in vitro flow phantom and the mathematical model were accurately measured with less than 10% errors. Simulation results demonstrated that the hematocrit (paired t tests, p = 0.5) and the tube radius (p = 0.1) do not influence the precision of the measured flow rate, whereas the shape of the velocity profile (p < 0.001) and the location of the focus plane (p < 0.001) do, as indicated by measured errors ranging from 3% to 97%. In conclusion, the use of RBCs as tracer particles makes a large DOC and affects the image processing required to estimate the flow velocities. We found that the current µPIV method is acceptable to estimate the flow rate

  15. Velocity-pressure correlation measurements in complex free shear flows

    International Nuclear Information System (INIS)

    Naka, Yoshitsugu; Obi, Shinnosuke

    2009-01-01

    Simultaneous measurements of fluctuating velocity and pressure were performed in various turbulent free shear flows including a turbulent mixing layer and the wing-tip vortex trailing from a NACA0012 half-wing. Two different methods for fluctuating static pressure measurement were considered: a direct method using a miniature Pitot tube and an indirect method where static pressure was calculated from total pressure. The pressure obtained by either of these methods was correlated with the velocity measured by an X-type hot-wire probe. The results from these two techniques agreed with each other in the turbulent mixing layer. In the wing-tip vortex case, however, some discrepancies were found, although overall characteristics of the pressure-related statistics were adequately captured by both methods.

  16. Gas and particle velocity measurements in an induction plasma

    International Nuclear Information System (INIS)

    Lesinski, J.; Gagne, R.; Boulos, M.I.

    1981-08-01

    Laser doppler anemometry was used for the measurements of the plasma and particle velocity profiles in the coil region of an inductively coupled plasma. Results are reported for a 50 mm ID induction torch operated at atmospheric pressure with argon as the plasma gas. The oscillator frequency was 3 MHz and the power in the coil was varied between 4.6 and 10.5 kW. The gas velocity measurements were made using a fine carbon powder as a tracer (dp approx. = 1 μm). Measurements were also made with larger silicon particles (dp = 33 μm and sigma = 13 μm) centrally injected in the plasma under different operating conditions

  17. Measurement uncertainty budget of an interferometric flow velocity sensor

    Science.gov (United States)

    Bermuske, Mike; Büttner, Lars; Czarske, Jürgen

    2017-06-01

    Flow rate measurements are a common topic for process monitoring in chemical engineering and food industry. To achieve the requested low uncertainties of 0:1% for flow rate measurements, a precise measurement of the shear layers of such flows is necessary. The Laser Doppler Velocimeter (LDV) is an established method for measuring local flow velocities. For exact estimation of the flow rate, the flow profile in the shear layer is of importance. For standard LDV the axial resolution and therefore the number of measurement points in the shear layer is defined by the length of the measurement volume. A decrease of this length is accompanied by a larger fringe distance variation along the measurement axis which results in a rise of the measurement uncertainty for the flow velocity (uncertainty relation between spatial resolution and velocity uncertainty). As a unique advantage, the laser Doppler profile sensor (LDV-PS) overcomes this problem by using two fan-like fringe systems to obtain the position of the measured particles along the measurement axis and therefore achieve a high spatial resolution while it still offers a low velocity uncertainty. With this technique, the flow rate can be estimated with one order of magnitude lower uncertainty, down to 0:05% statistical uncertainty.1 And flow profiles especially in film flows can be measured more accurately. The problem for this technique is, in contrast to laboratory setups where the system is quite stable, that for industrial applications the sensor needs a reliable and robust traceability to the SI units, meter and second. Small deviations in the calibration can, because of the highly position depending calibration function, cause large systematic errors in the measurement result. Therefore, a simple, stable and accurate tool is needed, that can easily be used in industrial surroundings to check or recalibrate the sensor. In this work, different calibration methods are presented and their influences to the

  18. Time measurements with a mobile device using sound

    Science.gov (United States)

    Wisman, Raymond F.; Spahn, Gabriel; Forinash, Kyle

    2018-05-01

    Data collection is a fundamental skill in science education, one that students generally practice in a controlled setting using equipment only available in the classroom laboratory. However, using smartphones with their built-in sensors and often free apps, many fundamental experiments can be performed outside the laboratory. Taking advantage of these tools often require creative approaches to data collection and exploring alternative strategies for experimental procedures. As examples, we present several experiments using smartphones and apps that record and analyze sound to measure a variety of physical properties.

  19. Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems (ERASMUS)

    Energy Technology Data Exchange (ETDEWEB)

    Bland, Geoffrey [NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)

    2016-06-30

    The use of small unmanned aircraft systems (sUAS) with miniature sensor systems for atmospheric research is an important capability to develop. The Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems (ERASMUS) project, lead by Dr. Gijs de Boer of the Cooperative Institute for Research in Environmental Sciences (CIRES- a partnership of NOAA and CU-Boulder), is a significant milestone in realizing this new potential. This project has clearly demonstrated that the concept of sUAS utilization is valid, and miniature instrumentation can be used to further our understanding of the atmospheric boundary layer in the arctic.

  20. Discharge estimation combining flow routing and occasional measurements of velocity

    Directory of Open Access Journals (Sweden)

    G. Corato

    2011-09-01

    Full Text Available A new procedure is proposed for estimating river discharge hydrographs during flood events, using only water level data at a single gauged site, as well as 1-D shallow water modelling and occasional maximum surface flow velocity measurements. One-dimensional diffusive hydraulic model is used for routing the recorded stage hydrograph in the channel reach considering zero-diffusion downstream boundary condition. Based on synthetic tests concerning a broad prismatic channel, the "suitable" reach length is chosen in order to minimize the effect of the approximated downstream boundary condition on the estimation of the upstream discharge hydrograph. The Manning's roughness coefficient is calibrated by using occasional instantaneous surface velocity measurements during the rising limb of flood that are used to estimate instantaneous discharges by adopting, in the flow area, a two-dimensional velocity distribution model. Several historical events recorded in three gauged sites along the upper Tiber River, wherein reliable rating curves are available, have been used for the validation. The outcomes of the analysis can be summarized as follows: (1 the criterion adopted for selecting the "suitable" channel length based on synthetic test studies has proved to be reliable for field applications to three gauged sites. Indeed, for each event a downstream reach length not more than 500 m is found to be sufficient, for a good performances of the hydraulic model, thereby enabling the drastic reduction of river cross-sections data; (2 the procedure for Manning's roughness coefficient calibration allowed for high performance in discharge estimation just considering the observed water levels and occasional measurements of maximum surface flow velocity during the rising limb of flood. Indeed, errors in the peak discharge magnitude, for the optimal calibration, were found not exceeding 5% for all events observed in the three investigated gauged sections, while the

  1. Velocity ratio measurement using the frequency of gyro backward wave

    International Nuclear Information System (INIS)

    Muggli, P.; Tran, M.Q.; Tran, T.M.

    1990-10-01

    The operating diagram of a low quality factor, 8GHz TE 01 0 gyrotron exhibits oscillations between 6.8 and 7.3GHz. These oscillations are identified as the backward wave component of the TE 21 0 traveling mode. As the resonance condition of this mode depends on the average parallel velocity [ > of the beam electrons (ω BW ≅Ω C /γ - k [ [ >), the measurement of ω BW for given Ω C and γ, is used as a diagnostic for the beam electrons velocity ratio α= / [ >. The values of α, deduced from ω BW through the linear dispersion relation for the electron cyclotron instability in an infinite waveguide, are unrealistic. A non-linear simulation code gives α values which are in very good agreement with the ones predicted by a particle trajectory code (+10% to +20%). We find numerically that the particles' velocity dispersion in vperpendicular and v [ increases ω BW . This effect explains part of the discrepancy between the values of α inferred from ω BW without velocity dispersion and the expected values. (author) 10 refs., 6 figs., 1 tab

  2. Measurements of phoretic velocities of aerosol particles in microgravity conditions

    Science.gov (United States)

    Prodi, F.; Santachiara, G.; Travaini, S.; Vedernikov, A.; Dubois, F.; Minetti, C.; Legros, J. C.

    2006-11-01

    Measurements of thermo- and diffusio-phoretic velocities of aerosol particles (carnauba wax, paraffin and sodium chloride) were performed in microgravity conditions (Drop Tower facility, in Bremen, and Parabolic Flights, in Bordeaux). In the case of thermophoresis, a temperature gradient was obtained by heating the upper plate of the cell, while the lower one was maintained at environmental temperature. For diffusiophoresis, the water vapour gradient was obtained with sintered plates imbued with a water solution of MgCl 2 and distilled water, at the top and at the bottom of the cell, respectively. Aerosol particles were observed through a digital holographic velocimeter, a device allowing the determination of 3-D coordinates of particles from the observed volume. Particle trajectories and consequently particle velocities were reconstructed through the analysis of the sequence of particle positions. The experimental values of reduced thermophoretic velocities are between the theoretical values of Yamamoto and Ishihara [Yamamoto, K., Ishihara, Y., 1988. Thermophoresis of a spherical particle in a rarefied gas of a transition regime. Phys. Fluids. 31, 3618-3624] and Talbot et al. [Talbot, L., Cheng, R.K., Schefer, R.W., Willis, D.R., 1980. Thermophoresis of particles in a heated boundary layer. J. Fluid Mech. 101, 737-758], and do not show a clear dependence on the thermal conductivity of the aerosol. The existence of negative thermophoresis is not confirmed in our experiments. Concerning diffusiophoretic experiments, the results obtained show a small increase of reduced diffusiophoretic velocity with the Knudsen number.

  3. Sound velocity profiles in the St. Clair and St. Mary's Rivers in the Great Lakes area by the National Ocean Service's Navigation Response Team 4, May 2006 (NODC Accession 0006777)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sound velocity profile data were collected using sound velocimeter in the St. Clair and St. Mary rivers in the Great Lakes area by the NAVIGATION RESPONSE TEAM 4...

  4. Model-assisted measurements of suspension-feeding flow velocities.

    Science.gov (United States)

    Du Clos, Kevin T; Jones, Ian T; Carrier, Tyler J; Brady, Damian C; Jumars, Peter A

    2017-06-01

    Benthic marine suspension feeders provide an important link between benthic and pelagic ecosystems. The strength of this link is determined by suspension-feeding rates. Many studies have measured suspension-feeding rates using indirect clearance-rate methods, which are based on the depletion of suspended particles. Direct methods that measure the flow of water itself are less common, but they can be more broadly applied because, unlike indirect methods, direct methods are not affected by properties of the cleared particles. We present pumping rates for three species of suspension feeders, the clams Mya arenaria and Mercenaria mercenaria and the tunicate Ciona intestinalis , measured using a direct method based on particle image velocimetry (PIV). Past uses of PIV in suspension-feeding studies have been limited by strong laser reflections that interfere with velocity measurements proximate to the siphon. We used a new approach based on fitting PIV-based velocity profile measurements to theoretical profiles from computational fluid dynamic (CFD) models, which allowed us to calculate inhalant siphon Reynolds numbers ( Re ). We used these inhalant Re and measurements of siphon diameters to calculate exhalant Re , pumping rates, and mean inlet and outlet velocities. For the three species studied, inhalant Re ranged from 8 to 520, and exhalant Re ranged from 15 to 1073. Volumetric pumping rates ranged from 1.7 to 7.4 l h -1 for M . arenaria , 0.3 to 3.6 l h -1 for M . m ercenaria and 0.07 to 0.97 l h -1 for C . intestinalis We also used CFD models based on measured pumping rates to calculate capture regions, which reveal the spatial extent of pumped water. Combining PIV data with CFD models may be a valuable approach for future suspension-feeding studies. © 2017. Published by The Company of Biologists Ltd.

  5. Velocity distribution measurement in wire-spaced fuel pin bundle

    International Nuclear Information System (INIS)

    Mizuta, Hiroshi; Ohtake, Toshihide; Uruwashi, Shinichi; Takahashi, Keiichi

    1974-01-01

    Flow distribution measurement was made in the subchannels of a pin bundle in air flow. The present paper is interim because the target of this work is the decision of temperature of the pin surface in contact with wire spacers. The wire-spaced fuel pin bundle used for the experiment consists of 37 simulated fuel pins of stainless steel tubes, 3000 mm in length and 31.6 mm in diameter, which are wound spirally with 6 mm stainless steel wire. The bundle is wrapped with a hexagonal tube, 3500 mm in length and 293 mm in flat-to-flat distance. The bundle is fixed with knock-bar at the entrance of air flow in the hexagonal tube. The pitch of pins in the bundle is 37.6 mm (P/D=1.19) and the wrapping pitch of wire is 1100 mm (H/D=34.8). A pair of arrow-type 5-hole Pitot tubes are used to measure the flow velocity and the direction of air flow in the pin bundle. The measurement of flow distribution was made with the conditions of air flow rate of 0.33 m 3 /sec, air temperature of 45 0 C, and average Reynolds number of 15100 (average air velocity of 20.6 m/sec.). It was found that circular flow existed in the down stream of wire spacers, that axial flow velocity was slower in the subchannels, which contained wire spacers, than in those not affected by the wire, and that the flow angle to the axial velocity at the boundary of subchannels was two thirds smaller than wire wrapping angle. (Tai, I.)

  6. Measured and modeled dry deposition velocities over the ESCOMPTE area

    Science.gov (United States)

    Michou, M.; Laville, P.; Serça, D.; Fotiadi, A.; Bouchou, P.; Peuch, V.-H.

    2005-03-01

    Measurements of the dry deposition velocity of ozone have been made by the eddy correlation method during ESCOMPTE (Etude sur Site pour COntraindre les Modèles de Pollution atmosphérique et de Transport d'Emissions). The strong local variability of natural ecosystems was sampled over several weeks in May, June and July 2001 for four sites with varying surface characteristics. The sites included a maize field, a Mediterranean forest, a Mediterranean shrub-land, and an almost bare soil. Measurements of nitrogen oxide deposition fluxes by the relaxed eddy correlation method have also been carried out at the same bare soil site. An evaluation of the deposition velocities computed by the surface module of the multi-scale Chemistry and Transport Model MOCAGE is presented. This module relies on a resistance approach, with a detailed treatment of the stomatal contribution to the surface resistance. Simulations at the finest model horizontal resolution (around 10 km) are compared to observations. If the seasonal variations are in agreement with the literature, comparisons between raw model outputs and observations, at the different measurement sites and for the specific observing periods, are contrasted. As the simulated meteorology at the scale of 10 km nicely captures the observed situations, the default set of surface characteristics (averaged at the resolution of a grid cell) appears to be one of the main reasons for the discrepancies found with observations. For each case, sensitivity studies have been performed in order to see the impact of adjusting the surface characteristics to the observed ones, when available. Generally, a correct agreement with the observations of deposition velocities is obtained. This advocates for a sub-grid scale representation of surface characteristics for the simulation of dry deposition velocities over such a complex area. Two other aspects appear in the discussion. Firstly, the strong influence of the soil water content to the plant

  7. Velocity field measurements on high-frequency, supersonic microactuators

    Science.gov (United States)

    Kreth, Phillip A.; Ali, Mohd Y.; Fernandez, Erik J.; Alvi, Farrukh S.

    2016-05-01

    The resonance-enhanced microjet actuator which was developed at the Advanced Aero-Propulsion Laboratory at Florida State University is a fluidic-based device that produces pulsed, supersonic microjets by utilizing a number of microscale, flow-acoustic resonance phenomena. The microactuator used in this study consists of an underexpanded source jet that flows into a cylindrical cavity with a single, 1-mm-diameter exhaust orifice through which an unsteady, supersonic jet issues at a resonant frequency of 7 kHz. The flowfields of a 1-mm underexpanded free jet and the microactuator are studied in detail using high-magnification, phase-locked flow visualizations (microschlieren) and two-component particle image velocimetry. These are the first direct measurements of the velocity fields produced by such actuators. Comparisons are made between the flow visualizations and the velocity field measurements. The results clearly show that the microactuator produces pulsed, supersonic jets with velocities exceeding 400 m/s for roughly 60 % of their cycles. With high unsteady momentum output, this type of microactuator has potential in a range of ow control applications.

  8. Velocity field measurement in micro-bubble emission boiling

    International Nuclear Information System (INIS)

    Ito, Daisuke; Saito, Yasushi; Natazuka, Jun

    2017-01-01

    Liquid inlet behavior to a heat surface in micro-bubble emission boiling (MEB) was investigated by flow measurement using particle image velocimetry (PIV). Subcooled pool boiling experiments under atmospheric pressure were carried out using a heat surface with a diameter of 10 mm. An upper end of a heater block made of copper was used as the heat surface. Working fluid was the deionized water and the subcooling was varied from 40 K to 70 K. Three K-type thermocouples were installed in the copper block to measure the temperature gradient, and the heat flux and wall superheat were estimated from these temperature data to make a boiling curve. The flow visualization around the heat surface was carried out using a high-speed video camera and a light sheet. The microbubbles generated in the MEB were used as tracer particles and the velocity field was obtained by PIV analysis of the acquired image sequence. As a result, the higher heat fluxes than the critical heat flux could be obtained in the MEB region. In addition, the distribution characteristics of the velocity in MEB region were studied using the PIV results and the location of the stagnation point in the velocity fields was discussed. (author)

  9. Predicted and measured velocity distribution in a model heat exchanger

    International Nuclear Information System (INIS)

    Rhodes, D.B.; Carlucci, L.N.

    1984-01-01

    This paper presents a comparison between numerical predictions, using the porous media concept, and measurements of the two-dimensional isothermal shell-side velocity distributions in a model heat exchanger. Computations and measurements were done with and without tubes present in the model. The effect of tube-to-baffle leakage was also investigated. The comparison was made to validate certain porous media concepts used in a computer code being developed to predict the detailed shell-side flow in a wide range of shell-and-tube heat exchanger geometries

  10. Particle Image Velocimetry (PIV) Measurements of Suspension-Feeding Velocities

    Science.gov (United States)

    Du Clos, K.; Jones, I. T.; Carrier, T. J.; Jumars, P. A.

    2016-02-01

    Active suspension feeders, such as bivalves and tunicates, connect benthic and pelagic ecosystems by packaging suspended matter into larger fecal and pseudofecal particles, greatly enhancing the flux of carbon and nutrients from the water column to the benthos. The volume of water processed by a population of suspension feeders is commonly estimated by scaling up results from experiments that measure the clearance rate (the volume of water cleared of particles per time) of one or a few individual suspension feeders. Clearance rates vary, however, between species, within a species, and over time for a single individual; and the velocity fields produced by suspension feeders are likely to interact in complex ways. We measured the water velocity fields produced by two species of bivalve, Mya arenaria and Mercenaria mercenaria, and the tunicate Ciona intestinalis, using particle image velocimetry (PIV). We used these measurements to calculate flow rates and Reynolds numbers of inhalant and exhalant siphons. We also observed strong entrainment of water by M. arenaria's exhalant siphon jet that may help to explain how the clam avoids depleting the water around it of particles and oxygen as it feeds. We are using these measurements to inform computational fluid mechanics (CFD) models of suspension feeding, allowing us to examine the interactions of flow fields produced by multiple suspension feeders and other effects not quantified by clearance-rate measurements.

  11. A PRACTICAL APPROACH TO THE GROUND OSCILLATION VELOCITY MEASUREMENT METHOD

    Directory of Open Access Journals (Sweden)

    Siniša Stanković

    2017-01-01

    Full Text Available The use of an explosive’s energy during blasting includes undesired effects on the environment. The seismic influence of a blast, as a major undesired effect, is determined by many national standards, recommendations and calculations where the main parameter is ground oscillation velocity at the field measurement location. There are a few approaches and methods for calculation of expected ground oscillation velocities according to charge weight per delay and the distance from the blast to the point of interest. Utilizations of these methods and formulas do not provide satisfactory results, thus the measured values on diverse distance from the blast field more or less differ from values given by previous calculations. Since blasting works are executed in diverse geological conditions, the aim of this research is the development of a practical and reliable approach which will give a different model for each construction site where blasting works have been or will be executed. The approach is based on a greater number of measuring points in line from the blast field at predetermined distances. This new approach has been compared with other generally used methods and formulas through the use of measurements taken during research along with measurements from several previously executed projects. The results confirmed that the suggested model gives more accurate values.

  12. Glottal volume velocity waveform characteristics in subjects with and without vocal training, related to gender, sound intensity, fundamental frequency, and age

    NARCIS (Netherlands)

    Sulter, AM; Wit, HP

    Glottal volume velocity waveform characteristics of 224 subjects, categorized in four groups according to gender and vocal training, were determined, and their relations to sound-pressure level, fundamental frequency, intra-oral pressure, and age were analyzed. Subjects phonated at three intensity

  13. Glottal volume velocity waveform characteristics in subjects with and without vocal training, related to gender, sound intensity, fundamental frequency, and age

    NARCIS (Netherlands)

    Sulter, AM; Wit, HP

    1996-01-01

    Glottal volume velocity waveform characteristics of 224 subjects, categorized in four groups according to gender and vocal training, were determined, and their relations to sound-pressure level, fundamental frequency, intra-oral pressure, and age were analyzed. Subjects phonated at three intensity

  14. Evaluating signal-to-noise ratios, loudness, and related measures as indicators of airborne sound insulation.

    Science.gov (United States)

    Park, H K; Bradley, J S

    2009-09-01

    Subjective ratings of the audibility, annoyance, and loudness of music and speech sounds transmitted through 20 different simulated walls were used to identify better single number ratings of airborne sound insulation. The first part of this research considered standard measures such as the sound transmission class the weighted sound reduction index (R(w)) and variations of these measures [H. K. Park and J. S. Bradley, J. Acoust. Soc. Am. 126, 208-219 (2009)]. This paper considers a number of other measures including signal-to-noise ratios related to the intelligibility of speech and measures related to the loudness of sounds. An exploration of the importance of the included frequencies showed that the optimum ranges of included frequencies were different for speech and music sounds. Measures related to speech intelligibility were useful indicators of responses to speech sounds but were not as successful for music sounds. A-weighted level differences, signal-to-noise ratios and an A-weighted sound transmission loss measure were good predictors of responses when the included frequencies were optimized for each type of sound. The addition of new spectrum adaptation terms to R(w) values were found to be the most practical approach for achieving more accurate predictions of subjective ratings of transmitted speech and music sounds.

  15. Pressure drop ana velocity measurements in KMRR fuel rod bundles

    International Nuclear Information System (INIS)

    Yagn, Sun Kyu; Chung, Heung June; Chung, Chang Whan; Chun, Se Young; Song, Chul Wha; Won, Soon Yeun; Chung, Moon Ki

    1990-01-01

    The detailed hydraulic characteristic measurements in subchannels of longitudinally finned rod bundles using one-component LDV(Laser Doppler Velocimeter) were performed. Time mean axial velocity, turbulent intensity, and turbulent micro scales, such as time auto-correlation, Eulerian integral and micro scale, Kolmogorov length and time scale, and Taylor micro length scale were measured. The signals from LDV are inherently more or less discontinuous. The spectra of signals having such intermittent defects can be obtained by the fast Fourier transformation (FFT) of the auto-correlation function. The turbulent crossflow mixing rate between neighboring subchannels and dominant frequencies were evaluated from the measured data. Pressure drop data were obtained for the typical 36-element and 18-element fuel rod bundles fabricated by the design requirement of KMRR fuel and for other type of fuels assembled with 6-fin rods to investigate the fin effects on the pressure drop characteristics

  16. Determination of elastic anisotropy of rocks from P- and S-wave velocities: numerical modelling and lab measurements

    Science.gov (United States)

    Svitek, Tomáš; Vavryčuk, Václav; Lokajíček, Tomáš; Petružálek, Matěj

    2014-12-01

    The most common type of waves used for probing anisotropy of rocks in laboratory is the direct P wave. Information potential of the measured P-wave velocity, however, is limited. In rocks displaying weak triclinic anisotropy, the P-wave velocity depends just on 15 linear combinations of 21 elastic parameters, called the weak-anisotropy parameters. In strong triclinic anisotropy, the P-wave velocity depends on the whole set of 21 elastic parameters, but inversion for six of them is ill-conditioned and these parameters are retrieved with a low accuracy. Therefore, in order to retrieve the complete elastic tensor accurately, velocities of S waves must also be measured and inverted. For this purpose, we developed a lab facility which allows the P- and S-wave ultrasonic sounding of spherical rock samples in 132 directions distributed regularly over the sphere. The velocities are measured using a pair of P-wave sensors with the transmitter and receiver polarized along the radial direction and using two pairs of S-wave sensors with the transmitter and receiver polarized tangentially to the spherical sample in mutually perpendicular directions. We present inversion methods of phase and ray velocities for elastic parameters describing general triclinic anisotropy. We demonstrate on synthetic tests that the inversion becomes more robust and stable if the S-wave velocities are included. This applies even to the case when the velocity of the S waves is measured in a limited number of directions and with a significantly lower accuracy than that of the P wave. Finally, we analyse velocities measured on a rock sample from the Outokumpu deep drill hole, Finland. We present complete sets of elastic parameters of the sample including the error analysis for several levels of confining pressure ranging from 0.1 to 70 MPa.

  17. Using piezoelectric sensors for ultrasonic pulse velocity measurements in concrete

    International Nuclear Information System (INIS)

    Kee, Seong-Hoon; Zhu, Jinying

    2013-01-01

    The ultrasonic pulse velocity (UPV) test has been a widely used non-destructive testing method for concrete structures. However, the conventional UPV test has limitations in consistency of results and applicability in hard-to-access regions of structures. The authors explore the feasibility of embedded piezoelectric (PZT) sensors for ultrasonic measurements in concrete structures. Two PZT sensors were embedded in a reinforced concrete specimen. One sensor worked as an actuator driven by an ultrasonic pulse-receiver, and another sensor worked as a receiver. A series of ultrasonic tests were conducted to investigate the performance of the embedded sensors in crack-free concrete and concrete specimens having a surface-breaking crack under various external loadings. Signals measured by the embedded sensors show a broad bandwidth with a centre frequency around 80 kHz, and very good coherence in the frequency range from 30 to 180 kHz. Furthermore, experimental variability in ultrasonic pulse velocity and attenuation is substantially reduced compared to previously reported values from conventional UPV equipment. Findings from this study demonstrate that the embedded sensors have great potential as a low-cost solution for ultrasonic transducers for health monitoring of concrete in structures. (paper)

  18. Measurement of acoustic velocity components in a turbulent flow using LDV and high-repetition rate PIV

    Science.gov (United States)

    Léon, Olivier; Piot, Estelle; Sebbane, Delphine; Simon, Frank

    2017-06-01

    The present study provides theoretical details and experimental validation results to the approach proposed by Minotti et al. (Aerosp Sci Technol 12(5):398-407, 2008) for measuring amplitudes and phases of acoustic velocity components (AVC) that are waveform parameters of each component of velocity induced by an acoustic wave, in fully turbulent duct flows carrying multi-tone acoustic waves. Theoretical results support that the turbulence rejection method proposed, based on the estimation of cross power spectra between velocity measurements and a reference signal such as a wall pressure measurement, provides asymptotically efficient estimators with respect to the number of samples. Furthermore, it is shown that the estimator uncertainties can be simply estimated, accounting for the characteristics of the measured flow turbulence spectra. Two laser-based measurement campaigns were conducted in order to validate the acoustic velocity estimation approach and the uncertainty estimates derived. While in previous studies estimates were obtained using laser Doppler velocimetry (LDV), it is demonstrated that high-repetition rate particle image velocimetry (PIV) can also be successfully employed. The two measurement techniques provide very similar acoustic velocity amplitude and phase estimates for the cases investigated, that are of practical interest for acoustic liner studies. In a broader sense, this approach may be beneficial for non-intrusive sound emission studies in wind tunnel testings.

  19. Sound Power Estimation by Laser Doppler Vibration Measurement Techniques

    Directory of Open Access Journals (Sweden)

    G.M. Revel

    1998-01-01

    Full Text Available The aim of this paper is to propose simple and quick methods for the determination of the sound power emitted by a vibrating surface, by using non-contact vibration measurement techniques. In order to calculate the acoustic power by vibration data processing, two different approaches are presented. The first is based on the method proposed in the Standard ISO/TR 7849, while the second is based on the superposition theorem. A laser-Doppler scanning vibrometer has been employed for vibration measurements. Laser techniques open up new possibilities in this field because of their high spatial resolution and their non-intrusivity. The technique has been applied here to estimate the acoustic power emitted by a loudspeaker diaphragm. Results have been compared with those from a commercial Boundary Element Method (BEM software and experimentally validated by acoustic intensity measurements. Predicted and experimental results seem to be in agreement (differences lower than 1 dB thus showing that the proposed techniques can be employed as rapid solutions for many practical and industrial applications. Uncertainty sources are addressed and their effect is discussed.

  20. Producing of Impedance Tube for Measurement of Acoustic Absorption Coefficient of Some Sound Absorber Materials

    Directory of Open Access Journals (Sweden)

    R. Golmohammadi

    2008-04-01

    Full Text Available Introduction & Objective: Noise is one of the most important harmful agents in work environment. In spit of industrial improvements, exposure with over permissible limit of noise is counted as one of the health complication of workers. In Iran, do not exact information of the absorption coefficient of acoustic materials. Iranian manufacturer have not laboratory for measured of sound absorbance of their products, therefore using of sound absorber is limited for noise control in industrial and non industrial constructions. The goal of this study was to design an impedance tube based on pressure method for measurement of the sound absorption coefficient of acoustic materials.Materials & Methods: In this study designing of measuring system and method of calculation of sound absorption based on a available equipment and relatively easy for measurement of the sound absorption coefficient related to ISO10534-1 was performed. Measuring system consist of heavy asbestos tube, a pure tone sound generator, calibrated sound level meter for measuring of some commonly of sound absorber materials was used. Results: In this study sound absorption coefficient of 23 types of available acoustic material in Iran was tested. Reliability of results by three repeat of measurement was tested. Results showed that the standard deviation of sound absorption coefficient of study materials was smaller than .Conclusion: The present study performed a necessary technology of designing and producing of impedance tube for determining of acoustical materials absorption coefficient in Iran.

  1. Measurements of Turbulence at Two Tidal Energy Sites in Puget Sound, WA

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, Jim; Polagye, Brian; Durgesh, Vibhav; Richmond, Marshall C.

    2012-06-05

    Field measurements of turbulence are pre- sented from two sites in Puget Sound, WA (USA) that are proposed for electrical power generation using tidal current turbines. Rapidly sampled data from multiple acoustic Doppler instruments are analyzed to obtain statistical mea- sures of fluctuations in both the magnitude and direction of the tidal currents. The resulting turbulence intensities (i.e., the turbulent velocity fluctuations normalized by the harmonic tidal currents) are typically 10% at the hub- heights (i.e., the relevant depth bin) of the proposed turbines. Length and time scales of the turbulence are also analyzed. Large-scale, anisotropic eddies dominate the energy spectra, which may be the result of proximity to headlands at each site. At small scales, an isotropic turbulent cascade is observed and used to estimate the dissipation rate of turbulent kinetic energy. Data quality and sampling parameters are discussed, with an emphasis on the removal of Doppler noise from turbulence statistics.

  2. Force-velocity measurements of a few growing actin filaments.

    Directory of Open Access Journals (Sweden)

    Coraline Brangbour

    2011-04-01

    Full Text Available The polymerization of actin in filaments generates forces that play a pivotal role in many cellular processes. We introduce a novel technique to determine the force-velocity relation when a few independent anchored filaments grow between magnetic colloidal particles. When a magnetic field is applied, the colloidal particles assemble into chains under controlled loading or spacing. As the filaments elongate, the beads separate, allowing the force-velocity curve to be precisely measured. In the widely accepted Brownian ratchet model, the transduced force is associated with the slowing down of the on-rate polymerization. Unexpectedly, in our experiments, filaments are shown to grow at the same rate as when they are free in solution. However, as they elongate, filaments are more confined in the interspace between beads. Higher repulsive forces result from this higher confinement, which is associated with a lower entropy. In this mechanism, the production of force is not controlled by the polymerization rate, but is a consequence of the restriction of filaments' orientational fluctuations at their attachment point.

  3. [SOUND CONTACTS] Aspects of touch and timbre in piano performance. The effects of key velocity, articulation and temporal duration on sound

    Directory of Open Access Journals (Sweden)

    Eleonora Kojucharov

    2015-02-01

    Full Text Available The concept of touch in piano pedagogy is generally described by using abstract adjectives often linked to imagination, leading to a blurred and controversial definition of the term touch, often confused with timbre. In the last decades, new data-collection technologies and MIDI-based analysis allowed researchers to measure key-control specific features in timbre nuances modeling [Goebl-Bresin-Galembo 2004; Bernays-Traube 2011; 2013]. Within the field of piano performance, the present study attempts to objectively describe piano touch and the means with which it can be controlled, by: (1 providing elements for an adequate scientific understanding of touch; (2 clarifying the relationship between touch and timbre; (3 defining the extent to which the parameters of key-velocity, tempo and articulation vary as a function of different types of touch.

  4. Dynamic PIV measurement of the effect of sound waves in the upper plenum of the boiling water reactor

    International Nuclear Information System (INIS)

    Kumagai, Kosuke; Someya, Satoshi; Okamoto, Koji

    2008-01-01

    In recent years, power uprating of boiling power reactors has been conducted at several existing power plants in order to improve plant economy. In one power uprated plant (117.8% uprate) in the United States, steam dryer breakages due to fatigue fracture occurred. It is conceivable that the increased steam flow passing through the branches caused a self-induced vibration with the propagation of sound waves into the steam-dome. The resonance among the structure, the flow, and the pressure fluctuation resulted in the breakages. In order to clarify the basic mechanism of the resonance, previous studies were performed by conducting a point measurement of the pressure and a phase averaged measurement of the flow, although detecting the interaction among the structure, the flow, and the pressure fluctuation by the conventional method was difficult. In a preliminary study, a dynamic Particle Image Velocimetry (PIV) system was used to investigate the effect of sound on the flow. A dynamic PIV system is the newest entrant to the field of fluid flow measurement. Its paramount advantage is the instantaneous global evaluation of conditions over a plane extended across the entire velocity field. Using the dynamic PIV system, the influence of sound waves on the flow field was measured. As a result, when two speakers were placed diagonally and sound waves were presented in the same phase, vertical motion was strongly observed compared to horizontal motion. (author)

  5. Measuring the Edge Recombination Velocity of Monolayer Semiconductors.

    Science.gov (United States)

    Zhao, Peida; Amani, Matin; Lien, Der-Hsien; Ahn, Geun Ho; Kiriya, Daisuke; Mastandrea, James P; Ager, Joel W; Yablonovitch, Eli; Chrzan, Daryl C; Javey, Ali

    2017-09-13

    Understanding edge effects and quantifying their impact on the carrier properties of two-dimensional (2D) semiconductors is an essential step toward utilizing this material for high performance electronic and optoelectronic devices. WS 2 monolayers patterned into disks of varying diameters are used to experimentally explore the influence of edges on the material's optical properties. Carrier lifetime measurements show a decrease in the effective lifetime, τ effective , as a function of decreasing diameter, suggesting that the edges are active sites for carrier recombination. Accordingly, we introduce a metric called edge recombination velocity (ERV) to characterize the impact of 2D material edges on nonradiative carrier recombination. The unpassivated WS 2 monolayer disks yield an ERV ∼ 4 × 10 4 cm/s. This work quantifies the nonradiative recombination edge effects in monolayer semiconductors, while simultaneously establishing a practical characterization approach that can be used to experimentally explore edge passivation methods for 2D materials.

  6. Determination of groundwater flow velocity by radon measurements

    International Nuclear Information System (INIS)

    Hohn, E.; von Gunten, H.R.

    1990-01-01

    The groundwater resources of glacio-fluvial perialpine valleys are recharged significantly by the infiltration from rivers. The groundwater residence times between rivers and wells should be known in groundwater management problems. Short residence times can be estimated using radon. Radon concentrations in rivers are usually very low. Upon filtration and movement of the water in the ground, radon is picked up and its concentration increases by 2-3 orders of magnitude according to radioactive growth laws. Residence times and flow velocities can be estimated from the increasing radon concentrations measured in groundwater sampling tubes at different distances from the river. Results obtained with this method agree with the results from experiments with artificial tracers

  7. Radio-controlled boat for measuring water velocities and bathymetry

    Science.gov (United States)

    Vidmar, Andrej; Bezak, Nejc; Sečnik, Matej

    2016-04-01

    Radio-controlled boat named "Hi3" was designed and developed in order to facilitate water velocity and bathymetry measurements. The boat is equipped with the SonTek RiverSurveyor M9 instrument that is designed for measuring open channel hydraulics (discharge and bathymetry). Usually channel cross sections measurements are performed either from a bridge or from a vessel. However, these approaches have some limitations such as performing bathymetry measurements close to the hydropower plant turbine or downstream from a hydropower plant gate where bathymetry changes are often the most extreme. Therefore, the radio-controlled boat was designed, built and tested in order overcome these limitations. The boat is made from a surf board and two additional small balance support floats. Additional floats are used to improve stability in fast flowing and turbulent parts of rivers. The boat is powered by two electric motors, steering is achieved with changing the power applied to left and right motor. Furthermore, remotely controlled boat "Hi3" can be powered in two ways, either by a gasoline electric generator or by lithium batteries. Lithium batteries are lighter, quieter, but they operation time is shorter compared to an electrical generator. With the radio-controlled boat "Hi3" we can perform measurements in potentially dangerous areas such as under the lock gates at hydroelectric power plant or near the turbine outflow. Until today, the boat "Hi3" has driven more than 200 km in lakes and rivers, performing various water speed and bathymetry measurements. Moreover, in future development the boat "Hi3" will be upgraded in order to be able to perform measurements automatically. The future plans are to develop and implement the autopilot. With this approach the user will define the route that has to be driven by the boat and the boat will drive the pre-defined route automatically. This will be possible because of the very accurate differential GPS from the Sontek River

  8. Development of sound absorption measuring system with acoustic chamber; Kogata kyuon koka sokutei sochi no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Takahira, M.; Noba, M. [Toyota Motor Corp., Aichi (Japan); Matsuoka, H. [Nippon Soken, Inc., Tokyo (Japan)

    1998-05-01

    In order to measure sound absorption performance necessary to develop sound absorption materials, development was made on a device consisting of a small sound box capable of measurement inexpensively and easily, as a measure against the reverberation chamber method. In order to obtain stabilized diffusion sound internally, the sound box has a shape of asymmetric seven-side body in which sides do not face squarely with each other. The box was so sized that a large number of resonant vibration postures can be constituted at the targeted frequency simultaneously in the box. The box has a commercially available cone speaker with good acoustic output characteristics in frequency range of higher than 500 Hz installed on an inner side of the box. The sound source uses a method to derive sound absorption rate from difference of sound pressure levels. In order to eliminate need of averaging treatment by using a multi-point measurement inside the box, a discussion was given to provide an opening on part of the box to place the sound receiving point outside the opening. A square test piece is placed on the floor 0.5 meter or more away from the speaker in the box. As a result of the experiment, it was verified that the sound absorption rate obtained by this device corresponds well with that by the reverberation chamber method. The size of the test piece was also found adequate. 2 refs., 11 figs., 1 tab.

  9. Evaluating standard airborne sound insulation measures in terms of annoyance, loudness, and audibility ratings.

    Science.gov (United States)

    Park, H K; Bradley, J S

    2009-07-01

    This paper reports the results of an evaluation of the merits of standard airborne sound insulation measures with respect to subjective ratings of the annoyance and loudness of transmitted sounds. Subjects listened to speech and music sounds modified to represent transmission through 20 different walls with sound transmission class (STC) ratings from 34 to 58. A number of variations in the standard measures were also considered. These included variations in the 8-dB rule for the maximum allowed deficiency in the STC measure as well as variations in the standard 32-dB total allowed deficiency. Several spectrum adaptation terms were considered in combination with weighted sound reduction index (R(w)) values as well as modifications to the range of included frequencies in the standard rating contour. A STC measure without an 8-dB rule and an R(w) rating with a new spectrum adaptation term were better predictors of annoyance and loudness ratings of speech sounds. R(w) ratings with one of two modified C(tr) spectrum adaptation terms were better predictors of annoyance and loudness ratings of transmitted music sounds. Although some measures were much better predictors of responses to one type of sound than were the standard STC and R(w) values, no measure was remarkably improved for predicting annoyance and loudness ratings of both music and speech sounds.

  10. Directivity of Spherical Polyhedron Sound Source Used in Near-Field HRTF Measurements

    International Nuclear Information System (INIS)

    Yu Guang-Zheng; Xie Bo-Sun; Rao Dan

    2010-01-01

    The omnidirectional character is one of important requirements for the sound source used in near-field head-related transfer function (HRTF) measurements. Based on the analysis on the radiation sound pressure and directivity character of various spherical polyhedron sound sources, a spherical dodecahedral sound source with radius of 0.035m is proposed and manufactured. Theoretical and measured results indicate that the sound source is approximately omnidirectional below the frequency of 8 kHz. In addition, the sound source has reasonable magnitude response from 350Hz to 20kHz and linear phase characteristics. Therefore, it is suitable for the near-field HRTF measurements. (fundamental areas of phenomenology(including applications))

  11. Video Measurement of the Muzzle Velocity of a Potato Gun

    Science.gov (United States)

    Jasperson, Christopher; Pollman, Anthony

    2011-01-01

    Using first principles, a theoretical equation for the maximum and actual muzzle velocities for a pneumatic cannon was recently derived. For a fixed barrel length, this equation suggests that the muzzle velocity can be enhanced by maximizing the product of the initial pressure and the volume of the propellant gas and decreasing the projectile…

  12. Particle velocity measurements in laser irradiated foils using ORVIS

    International Nuclear Information System (INIS)

    Sheffield, S.A.; Fisk, G.A.

    1983-01-01

    Aluminum foils from 2- to 200-μm thick have been subjected to a Nd:YAG laser pulse of low irradiance (10 9 W/cm 2 , approx. 10 ns pulse) to produce laser-driven shocks in the foils. The particle velocity history of the foil side opposite the laser deposition was monitored with nanosecond resolution by a velocity interferometer system called ORVIS. These histories indicate a shock reverberation process accelerates the foil. Peak foil velocities can be adequately calculated using a ricket propulsion model developed from experiments at much higher irradiances. A velocity of 1 km/s was developed in a 2-μm-thick free foil in a time of 50 ns. Water-confined foils attained peak particle velocities about three times higher than those of free foils

  13. Development of Optophone with No Diaphragm and Application to Sound Measurement in Jet Flow

    Directory of Open Access Journals (Sweden)

    Yoshito Sonoda

    2012-01-01

    Full Text Available The optophone with no diaphragm, which can detect sound waves without disturbing flow of air and sound field, is presented as a novel sound measurement technique and the present status of development is reviewed in this paper. The method is principally based on the Fourier optics and the sound signal is obtained by detecting ultrasmall diffraction light generated from phase modulation by sounds. The principle and theory, which have been originally developed as a plasma diagnostic technique to measure electron density fluctuations in the nuclear fusion research, are briefly introduced. Based on the theoretical analysis, property and merits as a wave-optical sound detection are presented, and the fundamental experiments and results obtained so far are reviewed. It is shown that sounds from about 100 Hz to 100 kHz can be simultaneously detected by a visible laser beam, and the method is very useful to sound measurement in aeroacoustics. Finally, present main problems of the optophone for practical uses in sound and/or noise measurements and the image of technology expected in the future are shortly shown.

  14. Third sound measurements of superfluid 4He films on multiwall carbon nanotubes below 1 K

    International Nuclear Information System (INIS)

    Menachekanian, Emin; Abraham, John B S; Chen, Bob; Iaia, Vito; Li, Andrew; Williams, Gary A

    2014-01-01

    Third sound is studied for superfluid films of 4He adsorbed on multiwall carbon nanotubes packed into an annular resonator. The third sound is generated with mechanical oscillation of the cell, and detected with carbon bolometers. A filling curve at temperatures near 250 mK shows oscillations in the third sound velocity, with maxima at the completion of the 4th and 5th atomic layers. Sharp changes in the Q factor of the third sound are found at partial layer fillings. Temperature sweeps at a number of fill points show strong broadening effects on the Kosterlitz-Thouless (KT) transition, and rapidly increasing dissipation, in qualitative agreement with the predictions of Machta and Guyer. At the 4th layer completion there is a sudden reduction of the transition temperature T KT , and then a recovery back to linear variation with temperature, although the slope is considerably smaller than the KT prediction

  15. The Microflown, an acoustic particle velocity sensor

    NARCIS (Netherlands)

    de Bree, H.E.

    2003-01-01

    The Microflown is an acoustic sensor directly measuring particle velocity instead of sound pressure, which is usually measured by conventional microphones. Since its invention in 1994 it is mostly used for measurement purposes (broadband1D and 3D-sound intensity measurement and acoustic impedance).

  16. Measurement of surface recombination velocity on heavily doped indium phosphide

    International Nuclear Information System (INIS)

    Jenkins, P.; Ghalla-Goradia, M.; Faur, M.; Bailey, S.

    1990-01-01

    The controversy surrounding the published low values of surface recombination velocity (SRV) in n-InP, solidified in recent years when modeling of existing n/p InP solar cells revealed that the front surface SRV had to be higher than 1 x 10 6 cm/sec in order to justify the poor blue response that is characteristic of all n/p InP solar cells. In this paper, SRV on heavily doped (>10 18 cm -3 )n-type and p-type InP is measured as a function of surface treatment. For the limited range of substrates and surface treatments studied, SRV and surface stability depend strongly on the surface treatment. SRVs of ∼10 5 cm/sec in both p-type and n-type InP are obtainable, but in n-type the low SRV surfaces were unstable, and the only stable surfaces on n-type had SRVs of >10 6 cm/sec

  17. Simultaneous measurements with 3D PIV and Acoustic Doppler Velocity Profiler

    NARCIS (Netherlands)

    Blanckaert, K.J.F.; McLelland, S.J.

    2009-01-01

    Simultaneous velocity measurements were taken using Particle Image Velocimetry (PIV) and an Acoustic Doppler Velocity Profiler (ADVP) in a sharp open-channel bend with an immobile gravel bed. The PIV measures 3D velocity vectors in a vertical plane (~40cm x 20cm) at a frequency of 7.5 Hz, whereas

  18. Velocity measurement of model vertical axis wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.A.; McWilliam, M. [Waterloo Univ., ON (Canada). Dept. of Mechanical Engineering

    2006-07-01

    An increasingly popular solution to future energy demand is wind energy. Wind turbine designs can be grouped according to their axis of rotation, either horizontal or vertical. Horizontal axis wind turbines have higher power output in a good wind regime than vertical axis turbines and are used in most commercial class designs. Vertical axis Savonius-based wind turbine designs are still widely used in some applications because of their simplistic design and low wind speed performance. There are many design variables that must be considered in order to optimize the power output in a given wind regime in a typical wind turbine design. Using particle image velocimetry, a study of the air flow around five different model vertical axis wind turbines was conducted in a closed loop wind tunnel. A standard Savonius design with two semi-circular blades overlapping, and two variations of this design, a deep blade and a shallow blade design were among the turbine models included in this study. It also evaluated alternate designs that attempt to increase the performance of the standard design by allowing compound blade curvature. Measurements were collected at a constant phase angle and also at random rotor orientations. It was found that evaluation of the flow patterns and measured velocities revealed consistent and stable flow patterns at any given phase angle. Large scale flow structures are evident in all designs such as vortices shed from blade surfaces. An important performance parameter was considered to be the ability of the flow to remain attached to the forward blade and redirect and reorient the flow to the following blade. 6 refs., 18 figs.

  19. Video measurements of fluid velocities and water levels in breaking waves

    CSIR Research Space (South Africa)

    Govender, K

    2002-01-01

    Full Text Available The cost-effective measurement of the velocity flow fields in breaking water waves, using particle and correlation image velocimetry, is described. The fluid velocities are estimated by tracking the motion of neutrally buoyant particles and aeration...

  20. Binaural loudness for artificial-head measurements in directional sound fields

    DEFF Research Database (Denmark)

    Sivonen, Ville Pekka; Ellermeier, Wolfgang

    2008-01-01

    The effect of the sound incidence angle on loudness was investigated for fifteen listeners who matched the loudness of sounds coming from five different incidence angles in the horizontal plane to that of the same sound with frontal incidence. The stimuli were presented via binaural synthesis...... by using head-related transfer functions measured for an artificial head. The results, which exhibited marked individual differences, show that loudness depends on the direction from which a sound reaches the listener. The average results suggest a relatively simple rule for combining the two signals...... at the ears of an artificial head for binaural loudness predictions....

  1. A study of the river velocity measurement techniques and analysis methods

    Science.gov (United States)

    Chung Yang, Han; Lun Chiang, Jie

    2013-04-01

    Velocity measurement technology can be traced back to the pitot tube velocity measurement method in the 18th century and today's velocity measurement technology use the acoustic and radar technology, with the Doppler principle developed technology advances, in order to develop the measurement method is more suitable for the measurement of velocity, the purpose is to get a more accurate measurement data and with the surface velocity theory, the maximum velocity theory and the indicator theory to obtain the mean velocity. As the main research direction of this article is to review the literature of the velocity measurement techniques and analysis methods, and to explore the applicability of the measurement method of the velocity measurement instruments, and then to describe the advantages and disadvantages of the different mean velocity profiles analysis method. Adequate review of the references of this study will be able to provide a reference for follow-up study of the velocity measurement. Review velocity measurement literature that different velocity measurement is required to follow the different flow conditions measured be upgraded its accuracy, because each flow rate measurement method has its advantages and disadvantages. Traditional velocity instrument can be used at low flow and RiverRAD microwave radar or imaging technology measurement method may be applied in high flow. In the tidal river can use the ADCP to quickly measure river vertical velocity distribution. In addition, urban rivers may be used the CW radar to set up on the bridge, and wide rivers can be used RiverRAD microwave radar to measure the velocities. Review the relevant literature also found that using Ultrasonic Doppler Current Profiler with the Chiu's theory to the velocity of observing automation work can save manpower and resources to improve measurement accuracy, reduce the risk of measurement, but the great variability of river characteristics in Taiwan and a lot of drifting floating

  2. Research on Water Velocity Measurement of Reservoir Based on Pressure Sensor

    Directory of Open Access Journals (Sweden)

    Xiaoqiang Zhao

    2014-11-01

    Full Text Available To address the problem that pressure sensor can only measure the liquid level in reservoir, we designed a current velocity measurement system of reservoir based on pressure sensor, analyzed the error of current velocity measurement system, and proposed the error processing method and corresponding program. Several tests and experimental results show that in this measurement system, the liquid level measurement standard deviation is no more than 0.01 cm, and the current velocity measurement standard deviation is no more than 0.35 mL/s, which proves that the pressure sensor can measure both liquid level and current velocity synchronously.

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

    Science.gov (United States)

    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…

  4. Ocean current velocity, temperature and salinity collected during 2010 and 2011 in Vieques Sound and Virgin Passage (NODC Accession 0088063)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Nortek 600kHz Aquadopp acoustic current profilers were deployed between March 2010 and April 2011 on shallow water moorings located in Vieques Sound, Puerto Rico,...

  5. Estimated carotid-femoral pulse wave velocity has similar predictive value as measured carotid-femoral pulse wave velocity

    DEFF Research Database (Denmark)

    Olsen, Michael; Greve, Sara; Blicher, Marie

    2016-01-01

    OBJECTIVE: Carotid-femoral pulse wave velocity (cfPWV) adds significantly to traditional cardiovascular (CV) risk prediction, but is not widely available. Therefore, it would be helpful if cfPWV could be replaced by an estimated carotid-femoral pulse wave velocity (ePWV) using age and mean blood...... pressure and previously published equations. The aim of this study was to investigate whether ePWV could predict CV events independently of traditional cardiovascular risk factors and/or cfPWV. DESIGN AND METHOD: cfPWV was measured and ePWV calculated in 2366 apparently healthy subjects from four age...

  6. Design of channel experiment equipment for measuring coolant velocity of innovative research reactor

    International Nuclear Information System (INIS)

    Muhammad Subekti; Endiah Puji Hastuti; Dedi Heriyanto

    2014-01-01

    The design of innovative high flux research reactor (RRI) requires high power so that the capability core cooling requires to be improved by designing the faster core coolant velocity near to the critical velocity limit. Hence, the critical coolant velocity as the one of the important parameter of the reactor safety shall be measured by special equipment to the velocity limit that may induce fuel element degradation. The research aims is to calculate theoretically the critical coolant velocity and to design the special experiment equipment namely EXNal for measuring the critical coolant velocity in fuel element subchannel of the RRI. EXNal design considers the critical velocity calculation result of 20.52 m/s to determine the variation of flow rate of 4.5-29.2 m 3 /h, in which the experiment could simulate the 1-4X standard coolant velocity of RSG-GAS as well as destructive test of RRI's fuel plate. (author)

  7. Aortic pulse wave velocity measurement in systemic sclerosis patients

    Directory of Open Access Journals (Sweden)

    M. Sebastiani

    2012-12-01

    Full Text Available Background. Systemic sclerosis (SSc is characterized by endothelial dysfunction and widespread microangiopathy. However, a macrovascular damage could be also associated. Aortic pulse wave velocity (aPWV is known to be a reliable indicator of arterial stiffness and a useful prognostic predictor of cardiovascular events. Moreover, aPWV may be easily measured by non-invasive, user-friendly tool. Aim of our study was to evaluate aPWV alterations in a series of SSc patients. Methods. The aPWV was evaluated in 35 consecutive female SSc patients and 26 sex- and age-matched healthy controls. aPWV alterations were correlated with cardiopulmonary involvement. Results. A significant increase of aPWV was observed in SSc patients compared to controls (9.4±3.2 m/s vs 7.3±1 m/s; P=0.002. In particular, 14/35 (40% SSc patients and only 1/26 (4% controls (P=0.0009 showed increased aPWV (>9 m/s cut-off value. Moreover, echocardiography evaluation showed an increased prevalence of right atrial and ventricular dilatation (atrial volume: 23.6±6.2 mL vs 20.3±4.3 mL, P=0.026; ventricular diameter 19.5±4.9 mm vs 15.9±1.6 mm; P=0.001 associated to higher values of pulmonary arterial systolic pressure (PAPs in SSc patients (31.5±10.4 mmHg vs 21.6±2.9 mmHg; P50 years old. Furthermore, altered aPWV was more frequently associated with limited cutaneous pattern, longer disease duration (≥5 years, and/or presence of anticentromere antibody (ACA. Conclusions. A significantly higher prevalence of abnormally increased aPWV was evidenced in SSc patients compared to healthy controls. The possibility of more pronounced and diffuse vascular damage in a particular SSc subset (ACA-positive subjects with limited cutaneous scleroderma and longer disease duration might be raised.

  8. Temperature profile and sound velocity data using CTD casts from the US Naval Oceanographic Office as part of the Master Oceanographic Observation Data Set (MOODS) project, from 1975-04-11 to 1998-08-31 (NODC Accession 9900220)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and sound velocity data were collected using CTD, XCTD, and XBT casts in the Arctic Ocean, Mediterranean Sea - Eastern Basin, North Pacific...

  9. Method of measuring directed electron velocities in flowing plasma using the incoherent regions of laser scattering

    International Nuclear Information System (INIS)

    Jacoby, B.A.; York, T.M.

    1979-02-01

    With the presumption that a shifted Maxwellian velocity distribution adequately describes the electrons in a flowing plasma, the details of a method to measure their directed velocity are described. The system consists of a ruby laser source and two detectors set 180 0 from each other and both set at 90 0 with respect to the incident laser beam. The lowest velocity that can be determined by this method depends on the electron thermal velocity. The application of this diagnostic to the measurement of flow velocities in plasma being lost from the ends of theta-pinch devices is described

  10. Measurement of vortex velocities over a wide range of vortex age, downstream distance and free stream velocity

    Science.gov (United States)

    Rorke, J. B.; Moffett, R. C.

    1977-01-01

    A wind tunnel test was conducted to obtain vortex velocity signatures over a wide parameter range encompassing the data conditions of several previous researchers while maintaining a common instrumentation and test facility. The generating wing panel was configured with both a revolved airfoil tip shape and a square tip shape and had a semispan aspect of 4.05/1.0 with a 121.9 cm span. Free stream velocity was varied from 6.1 m/sec to 76.2 m/sec and the vortex core velocities were measured at locations 3, 6, 12, 24 and 48 chordlengths downstream of the wing trailing edge, yielding vortex ages up to 2.0 seconds. Wing pitch angles of 6, 8, 9 and 12 deg were investigated. Detailed surface pressure distributions and wing force measurements were obtained for each wing tip configuration. Correlation with vortex velocity data taken in previous experiments is good. During the rollup process, vortex core parameters appear to be dependent primarily on vortex age. Trending in the plateau and decay regions is more complex and the machanisms appear to be more unstable.

  11. An objective measure for the sensitivity of room impulse response and its link to a diffuse sound field

    DEFF Research Database (Denmark)

    Prislan, Rok; Brunskog, Jonas; Jacobsen, Finn

    2014-01-01

    This study is relevant to acoustic measurements in reverberation rooms such as measurements of sound transmission, sound absorption, and sound power levels of noise sources. The study presents a quantitative measure for the diffuseness in a room, which is first introduced theoretically and sub...

  12. Laser-induced fluorescence measurements of argon and xenon ion velocities near the sheath boundary in 3 ion species plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Yip, Chi-Shung; Hershkowitz, Noah [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Severn, Greg [Department of Physics, University of San Diego, San Diego, California 92110 (United States); Baalrud, Scott D. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

    2016-05-15

    The Bohm sheath criterion is studied with laser-induced fluorescence in three ion species plasmas using two tunable diode lasers. Krypton is added to a low pressure unmagnetized DC hot filament discharge in a mixture of argon and xenon gas confined by surface multi-dipole magnetic fields. The argon and xenon ion velocity distribution functions are measured at the sheath-presheath boundary near a negatively biased boundary plate. The potential structures of the plasma sheath and presheath are measured by an emissive probe. Results are compared with previous experiments with Ar–Xe plasmas, where the two ion species were observed to reach the sheath edge at nearly the same speed. This speed was the ion sound speed of the system, which is consistent with the generalized Bohm criterion. In such two ion species plasmas, instability enhanced collisional friction was demonstrated [Hershkowitz et al., Phys. Plasmas 18(5), 057102 (2011).] to exist which accounted for the observed results. When three ion species are present, it is demonstrated under most circumstances the ions do not fall out of the plasma at their individual Bohm velocities. It is also shown that under most circumstances the ions do not fall out of the plasma at the system sound speed. These observations are also consistent with the presence of the instabilities.

  13. Techniques and instrumentation for the measurement of transient sound energy flux

    Science.gov (United States)

    Watkinson, P. S.; Fahy, F. J.

    1983-12-01

    The evaluation of sound intensity distributions, and sound powers, of essentially continuous sources such as automotive engines, electric motors, production line machinery, furnaces, earth moving machinery and various types of process plants were studied. Although such systems are important sources of community disturbance and, to a lesser extent, of industrial health hazard, the most serious sources of hearing hazard in industry are machines operating on an impact principle, such as drop forges, hammers and punches. Controlled experiments to identify major noise source regions and mechanisms are difficult because it is normally impossible to install them in quiet, anechoic environments. The potential for sound intensity measurement to provide a means of overcoming these difficulties has given promising results, indicating the possibility of separation of directly radiated and reverberant sound fields. However, because of the complexity of transient sound fields, a fundamental investigation is necessary to establish the practicability of intensity field decomposition, which is basic to source characterization techniques.

  14. Direct measurement technique for shock wave velocity with irradiation drive

    International Nuclear Information System (INIS)

    Wang Feng; Peng Xiaoshi; Liu Shenye; Jiang Xiaohua; Ding Yongkun

    2011-01-01

    According to the ionization mechanism of transparent material under super high pressure, the direct diagnosis method of shock wave has been analyzed. With the Drude free electron model, the reflectivity difference of shock wave front under different pressures was analyzed. The blank effect in the detector was studied, which is caused by the X-ray ionization of transparent material, after analyzing the reflectivity data in space-time scale. The experiment shows that the beginning point and duration of blank effect are consistent with the start point and duration of laser pulse, respectively. And the reflectivity of shock wave front is about 35% when the shock velocity is 32 km/s. The reason and solution for blank effect was presented. The formula to calculate the shock wave velocity in transparent material was also deduced and verified. (authors)

  15. Three-dimensional instantaneous velocity field measurement using ...

    Indian Academy of Sciences (India)

    2014-02-13

    Feb 13, 2014 ... Abstract. In the present study, a digital holography microscope has been developed to study instantaneous 3D velocity field in a square channel of 1000 × 1000 μm2 cross-section. The flow field is seeded with polystyrene microspheres of size dp = 2.1 μm. The volumetric flow rate is set equal to 20 μl/min.

  16. Bulk velocity measurements by video analysis of dye tracer in a macro-rough channel

    International Nuclear Information System (INIS)

    Ghilardi, T; Franca, M J; Schleiss, A J

    2014-01-01

    Steep mountain rivers have hydraulic and morphodynamic characteristics that hinder velocity measurements. The high spatial variability of hydraulic parameters, such as water depth (WD), river width and flow velocity, makes the choice of a representative cross-section to measure the velocity in detail challenging. Additionally, sediment transport and rapidly changing bed morphology exclude the utilization of standard and often intrusive velocity measurement techniques. The limited technical choices are further reduced in the presence of macro-roughness elements, such as large, relatively immobile boulders. Tracer tracking techniques are among the few reliable methods that can be used under these conditions to evaluate the mean flow velocity. However, most tracer tracking techniques calculate bulk flow velocities between two or more fixed cross-sections. In the presence of intense sediment transport resulting in an important temporal variability of the bed morphology, dead water zones may appear in the few selected measurement sections. Thus a technique based on the analysis of an entire channel reach is needed in this study. A dye tracer measurement technique in which a single camcorder visualizes a long flume reach is described and developed. This allows us to overcome the problem of the presence of dead water zones. To validate this video analysis technique, velocity measurements were carried out on a laboratory flume simulating a torrent, with a relatively gentle slope of 1.97% and without sediment transport, using several commonly used velocity measurement instruments. In the absence of boulders, salt injections, WD and ultrasonic velocity profiler measurements were carried out, along with dye injection technique. When boulders were present, dye tracer technique was validated only by comparison with salt tracer. Several video analysis techniques used to infer velocities were developed and compared, showing that dye tracking is a valid technique for bulk velocity

  17. Velocity measurement by vortex shedding. Contribution to the mass-flow measurement

    International Nuclear Information System (INIS)

    Martinez Piquer, T.

    1988-01-01

    The phenomenon of vortex shedding has been known for centuries and has been the subject of scientific studies for about one hundred years. It is only in the ten last years that is has been applied to the measurement of fluids velocity. In 1878 F. Strouhal observed the vortex shedding phenomenon and shown that the shedding frequency of a wire vibrating in the wind was related to the wire diameter and the wind velocity. Rayleigh, who introduced the non-dimensional Strouhal number, von Karman and Rohsko, carried out extensive work or the subject which indicated that vortex shedding could form the basis for a new type of flowmeter. The thesis describes two parallel lines of investigation which study in depth the practical applications of vortex shedding. The first one deals with the measure of velocity and it presents the novelty of a bluff body with a cross-section which has not been used until this day. This body is a circular cylinder with a two-dimensional slit along the diameter and situated in crossdirection to the fluid's stream. It possesses excellent characteristics and it is the most stable as a vortex shedder, which gives it great advantage to the rest of the shapes used until now. The detection of the vortex has been performed by measuring the pressure changes generated by the vortex on two posts situated just beside the slit. To calculate the frequency of the vortex shedding, we obtain the difference of the mentioned signals, which are the same and 180 out of phase. Finding out the period of the autocorrelation function of this signal we can estimate the velocity of the fluid. A logical equipment based on a microprocessor has been designed for the calculation using a zero-crossing time algorithm implemented in assembler language. The second line of research refers to a new method of measure mass flow. The pressure signal generated by the vortex has an intensity which is proportional to the density and to the square of the velocity. Since we have already

  18. MR flow velocity measurement using 2D phase contrast, assessment of imaging parameters

    International Nuclear Information System (INIS)

    Akata, Soichi; Fukushima, Akihiro; Abe, Kimihiko; Darkanzanli, A.; Gmitro, A.F.; Unger, E.C.; Capp, M.P.

    1999-01-01

    The two-dimensional (2D) phase contrast technique using balanced gradient pulses is utilized to measure flow velocities of cerebrospinal fluid and blood. Various imaging parameters affect the accuracy of flow velocity measurements to varying degrees. Assessment of the errors introduced by changing the imaging parameters are presented and discussed in this paper. A constant flow phantom consisting of a pump, a polyethylene tube and a flow meter was assembled. A clinical 1.5 Tesla MR imager was used to perform flow velocity measurements. The phase contrast technique was used to estimate the flow velocity of saline through the phantom. The effects of changes in matrix size, flip angle, flow compensation, and velocity encoding (VENC) value were tested in the pulse sequence. Gd-DTPA doped saline was used to study the effect of changing T1 on the accuracy of flow velocity measurement. Matrix size (within practical values), flip angle, and flow compensation had minimum impact on flow velocity measurements. T1 of the solution also had no effect on the accuracy of measuring the flow velocity. On the other hand, it was concluded that errors as high as 20% can be expected in the flow velocity measurements if the VENC value is not properly chosen. (author)

  19. MR flow velocity measurement using 2D phase contrast, assessment of imaging parameters

    Energy Technology Data Exchange (ETDEWEB)

    Akata, Soichi; Fukushima, Akihiro; Abe, Kimihiko [Tokyo Medical Coll. (Japan); Darkanzanli, A.; Gmitro, A.F.; Unger, E.C.; Capp, M.P.

    1999-11-01

    The two-dimensional (2D) phase contrast technique using balanced gradient pulses is utilized to measure flow velocities of cerebrospinal fluid and blood. Various imaging parameters affect the accuracy of flow velocity measurements to varying degrees. Assessment of the errors introduced by changing the imaging parameters are presented and discussed in this paper. A constant flow phantom consisting of a pump, a polyethylene tube and a flow meter was assembled. A clinical 1.5 Tesla MR imager was used to perform flow velocity measurements. The phase contrast technique was used to estimate the flow velocity of saline through the phantom. The effects of changes in matrix size, flip angle, flow compensation, and velocity encoding (VENC) value were tested in the pulse sequence. Gd-DTPA doped saline was used to study the effect of changing T1 on the accuracy of flow velocity measurement. Matrix size (within practical values), flip angle, and flow compensation had minimum impact on flow velocity measurements. T1 of the solution also had no effect on the accuracy of measuring the flow velocity. On the other hand, it was concluded that errors as high as 20% can be expected in the flow velocity measurements if the VENC value is not properly chosen. (author)

  20. Identification of impact force acting on composite laminated plates using the radiated sound measured with microphones

    Science.gov (United States)

    Atobe, Satoshi; Nonami, Shunsuke; Hu, Ning; Fukunaga, Hisao

    2017-09-01

    Foreign object impact events are serious threats to composite laminates because impact damage leads to significant degradation of the mechanical properties of the structure. Identification of the location and force history of the impact that was applied to the structure can provide useful information for assessing the structural integrity. This study proposes a method for identifying impact forces acting on CFRP (carbon fiber reinforced plastic) laminated plates on the basis of the sound radiated from the impacted structure. Identification of the impact location and force history is performed using the sound pressure measured with microphones. To devise a method for identifying the impact location from the difference in the arrival times of the sound wave detected with the microphones, the propagation path of the sound wave from the impacted point to the sensor is examined. For the identification of the force history, an experimentally constructed transfer matrix is employed to relate the force history to the corresponding sound pressure. To verify the validity of the proposed method, impact tests are conducted by using a CFRP cross-ply laminate as the specimen, and an impulse hammer as the impactor. The experimental results confirm the validity of the present method for identifying the impact location from the arrival time of the sound wave detected with the microphones. Moreover, the results of force history identification show the feasibility of identifying the force history accurately from the measured sound pressure using the experimental transfer matrix.

  1. Method for Estimating Evaporative Potential (IM/CLO) from ASTM Standard Single Wind Velocity Measures

    Science.gov (United States)

    2016-08-10

    IM/CLO) FROM ASTM STANDARD SINGLE WIND VELOCITY MEASURES DISCLAIMER The opinions or assertions contained herein are the private views of the...USARIEM TECHNICAL REPORT T16-14 METHOD FOR ESTIMATING EVAPORATIVE POTENTIAL (IM/CLO) FROM ASTM STANDARD SINGLE WIND VELOCITY... ASTM STANDARD SINGLE WIND VELOCITY MEASURES Adam W. Potter Biophysics and Biomedical Modeling Division U.S. Army Research Institute of Environmental

  2. Direct speed of sound measurement within the atmosphere during a national holiday in New Zealand

    Science.gov (United States)

    Vollmer, M.

    2018-05-01

    Measuring the speed of sound belongs to almost any physics curriculum. Two methods dominate, measuring resonance phenomena of standing waves or time-of-flight measurements. The second type is conceptually simpler, however, performing such experiments with dimensions of meters usually requires precise electronic time measurement equipment if accurate results are to be obtained. Here a time-of-flight measurement from a video recording is reported with a dimension of several km and an accuracy for the speed of sound of the order of 1%.

  3. Sound quality measures for speech in noise through a commercial hearing aid implementing digital noise reduction.

    Science.gov (United States)

    Ricketts, Todd A; Hornsby, Benjamin W Y

    2005-05-01

    This brief report discusses the affect of digital noise reduction (DNR) processing on aided speech recognition and sound quality measures in 14 adults fitted with a commercial hearing aid. Measures of speech recognition and sound quality were obtained in two different speech-in-noise conditions (71 dBA speech, +6 dB SNR and 75 dBA speech, +1 dB SNR). The results revealed that the presence or absence of DNR processing did not impact speech recognition in noise (either positively or negatively). Paired comparisons of sound quality for the same speech in noise signals, however, revealed a strong preference for DNR processing. These data suggest that at least one implementation of DNR processing is capable of providing improved sound quality, for speech in noise, in the absence of improved speech recognition.

  4. Calculation of sound propagation in fibrous materials

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1996-01-01

    Calculations of attenuation and velocity of audible sound waves in glass wools are presented. The calculations use only the diameters of fibres and the mass density of glass wools as parameters. The calculations are compared with measurements.......Calculations of attenuation and velocity of audible sound waves in glass wools are presented. The calculations use only the diameters of fibres and the mass density of glass wools as parameters. The calculations are compared with measurements....

  5. Functional analysis of third ventriculostomy patency with phase-contrast MRI velocity measurements

    International Nuclear Information System (INIS)

    Lev, S.; Bhadelia, R.A.; Estin, D.; Heilman, C.B.; Wolpert, S.M.

    1997-01-01

    Our purpose was to explore the utility of cine phase-contrast MRI velocity measurements in determining the functional status of third ventriculostomies, and to correlate the quantitative velocity data with clinical follow-up. We examined six patients with third ventriculostomies and 12 normal subjects by phase-contrast MRI. The maximum craniocaudal to maximum caudocranial velocity range was measured at regions of interest near the third ventricular floor, and in cerebrospinal fluid anterior to the upper pons and spinal cord on midline sagittal images. Ratios of the velocities of both the third ventricle and prepontine space to the space anterior to the spinal cord were obtained. The velocities near the third ventricular floor and in the pontine cistern were significantly higher in patients than in normal subjects, but the velocity anterior to the spinal cord was similar between the groups. The velocity ratios, used to normalize individual differences, were also higher in patients than in controls. Two patients had lower velocity ratios than their fellows at the third ventricular floor and in the pontine cistern; one required a shunt 11 months later, while in the other, who had a third ventricular/thalamic tumor, the lower values probably reflect distortion of the third ventricular floor. We conclude that phase-contrast MR velocity measurements, specifically the velocity ratio between the high pontine cistern and the space anterior to the spinal cord, can help determine the functional status of third ventriculostomies. (orig.)

  6. A Measuring Method About the Bullet Velocity in Electromagnetic Rail Gun

    Directory of Open Access Journals (Sweden)

    Jianming LIU

    2014-02-01

    Full Text Available The operating principle of electromagnetic rail gun by store capacitor was analyzed. A simulation model about the bullet velocity in the electromagnetic rail gun was built. The results of computer simulation experiment showed the relationships between the bullet velocity and the capacitor charging voltage and the pellet mass. By ten coil targets, a new kind of measuring method for the bullet velocity in electromagnetic rail gun was presented. The results of the actual experiment were analyzed. The improving method for measuring bullet velocity was put forward.

  7. Tutorial and Guidelines on Measurement of Sound Pressure Level in Voice and Speech

    Science.gov (United States)

    Švec, Jan G.; Granqvist, Svante

    2018-01-01

    Purpose: Sound pressure level (SPL) measurement of voice and speech is often considered a trivial matter, but the measured levels are often reported incorrectly or incompletely, making them difficult to compare among various studies. This article aims at explaining the fundamental principles behind these measurements and providing guidelines to…

  8. Whole Word Measures in Bilingual Children with Speech Sound Disorders

    Science.gov (United States)

    Burrows, Lauren; Goldstein, Brian A.

    2010-01-01

    Phonological acquisition traditionally has been measured using constructs that focus on segments rather than the whole words. Findings from recent research have suggested whole-word productions be evaluated using measures such as phonological mean length of utterance (pMLU) and the proportion of whole-word proximity (PWP). These measures have been…

  9. Prerequisites for Accurate Monitoring of River Discharge Based on Fixed-Location Velocity Measurements

    Science.gov (United States)

    Kästner, K.; Hoitink, A. J. F.; Torfs, P. J. J. F.; Vermeulen, B.; Ningsih, N. S.; Pramulya, M.

    2018-02-01

    River discharge has to be monitored reliably for effective water management. As river discharge cannot be measured directly, it is usually inferred from the water level. This practice is unreliable at places where the relation between water level and flow velocity is ambiguous. In such a case, the continuous measurement of the flow velocity can improve the discharge prediction. The emergence of horizontal acoustic Doppler current profilers (HADCPs) has made it possible to continuously measure the flow velocity. However, the profiling range of HADCPs is limited, so that a single instrument can only partially cover a wide cross section. The total discharge still has to be determined with a model. While the limitations of rating curves are well understood, there is not yet a comprehensive theory to assess the accuracy of discharge predicted from velocity measurements. Such a theory is necessary to discriminate which factors influence the measurements, and to improve instrument deployment as well as discharge prediction. This paper presents a generic method to assess the uncertainty of discharge predicted from range-limited velocity profiles. The theory shows that a major source of error is the variation of the ratio between the local and cross-section-averaged velocity. This variation is large near the banks, where HADCPs are usually deployed and can limit the advantage gained from the velocity measurement. We apply our theory at two gauging stations situated in the Kapuas River, Indonesia. We find that at one of the two stations the index velocity does not outperform a simple rating curve.

  10. Measurement of thermal plasma jet temperature and velocity by laser light lineshape analysis

    International Nuclear Information System (INIS)

    Snyder, S.C.; Reynolds, L.D.

    1991-01-01

    Two important parameters of thermal plasma jets are kinetic or gas temperatures and flow velocity. Gas temperatures have been traditionally measured using emission spectroscopy, but this method depends on either the generally unrealistic assumption of the existence of local thermodynamic equilibrium (LTE) within the plasma, or the use of various non-LTE or partial LTE models to relate the intensity of the emission lines to the gas temperature. Plasma jet velocities have been measured using laser Doppler velocimetry on particles injected into the plasma. However, this method is intrusive and it is not known how well the particle velocities represent the gas velocity. Recently, plasma jet velocities have been measured from the Doppler shift of laser light scattered by the plasma. In this case, the Doppler shift was determined from the difference in the transmission profile of a high resolution monochromator between red shifted and blue shifted scattered light. A direct approach to measuring localized temperatures and velocities is afforded by high resolution scattered light lineshape measurements. The linewidth of laser light scattered by atoms and ions can be related to the kinetic temperature without LTE assumptions, while a shift in the peak position relative to the incident laser lineshape yields the gas velocity. We report in this paper work underway to measure gas temperatures and velocities in an argon thermal plasma jet using high resolution lineshape analysis of scattered laser light

  11. Measurement of core velocity fluctuations and the dynamo in a reversed-field pinch

    International Nuclear Information System (INIS)

    Den Hartog, D.J.; Craig, D.; Fiksel, G.; Fontana, P.W.; Prager, S.C.; Sarff, J.S.; Chapman, J.T.

    1998-01-01

    Plasma flow velocity fluctuations have been directly measured in the high temperature magnetically confined plasma in the Madison Symmetric Torus (MST) Reversed-Field Pinch (RFP). These measurements show that the flow velocity fluctuations are correlated with magnetic field fluctuations. This initial measurement is subject to limitations of spatial localization and other uncertainties, but is evidence for sustainment of the RFP magnetic field configuration by the magnetohydrodynamic (MHD) dynamo. Both the flow velocity and magnetic field fluctuations are the result of global resistive MHD modes of helicity m = 1, n = 5--10 in the core of MST. Chord-averaged flow velocity fluctuations are measured in the core of MST by recording the Doppler shift of impurity line emission with a specialized high resolution and throughput grating spectrometer. Magnetic field fluctuations are recorded with a large array of small edge pickup coils, which allows spectral decomposition into discrete modes and subsequent correlation with the velocity fluctuation data

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

    Directory of Open Access Journals (Sweden)

    Martin Grossöhmichen

    2016-01-01

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

  13. Velocity Deficits in the Wake of Model Lemon Shark Dorsal Fins Measured with Particle Image Velocimetry

    Science.gov (United States)

    Terry, K. N.; Turner, V.; Hackett, E.

    2017-12-01

    Aquatic animals' morphology provides inspiration for human technological developments, as their bodies have evolved and become adapted for efficient swimming. Lemon sharks exhibit a uniquely large second dorsal fin that is nearly the same size as the first fin, the hydrodynamic role of which is unknown. This experimental study looks at the drag forces on a scale model of the Lemon shark's unique two-fin configuration in comparison to drag forces on a more typical one-fin configuration. The experiments were performed in a recirculating water flume, where the wakes behind the scale models are measured using particle image velocimetry. The experiments are performed at three different flow speeds for both fin configurations. The measured instantaneous 2D distributions of the streamwise and wall-normal velocity components are ensemble averaged to generate streamwise velocity vertical profiles. In addition, velocity deficit profiles are computed from the difference between these mean streamwise velocity profiles and the free stream velocity, which is computed based on measured flow rates during the experiments. Results show that the mean velocities behind the fin and near the fin tip are smallest and increase as the streamwise distance from the fin tip increases. The magnitude of velocity deficits increases with increasing flow speed for both fin configurations, but at all flow speeds, the two-fin configurations generate larger velocity deficits than the one-fin configurations. Because the velocity deficit is directly proportional to the drag force, these results suggest that the two-fin configuration produces more drag.

  14. High Precision UTDR Measurements by Sonic Velocity Compensation with Reference Transducer

    Directory of Open Access Journals (Sweden)

    Sam Stade

    2014-07-01

    Full Text Available An ultrasonic sensor design with sonic velocity compensation is developed to improve the accuracy of distance measurement in membrane modules. High accuracy real-time distance measurements are needed in membrane fouling and compaction studies. The benefits of the sonic velocity compensation with a reference transducer are compared to the sonic velocity calculated with the measured temperature and pressure using the model by Belogol’skii, Sekoyan et al. In the experiments the temperature was changed from 25 to 60 °C at pressures of 0.1, 0.3 and 0.5 MPa. The set measurement distance was 17.8 mm. Distance measurements with sonic velocity compensation were over ten times more accurate than the ones calculated based on the model. Using the reference transducer measured sonic velocity, the standard deviations for the distance measurements varied from 0.6 to 2.0 µm, while using the calculated sonic velocity the standard deviations were 21–39 µm. In industrial liquors, not only the temperature and the pressure, which were studied in this paper, but also the properties of the filtered solution, such as solute concentration, density, viscosity, etc., may vary greatly, leading to inaccuracy in the use of the Belogol’skii, Sekoyan et al. model. Therefore, calibration of the sonic velocity with reference transducers is needed for accurate distance measurements.

  15. A simple measuring technique of surface flow velocity to analyze the behavior of velocity fields in hydraulic engineering applications.

    Science.gov (United States)

    Tellez, Jackson; Gomez, Manuel; Russo, Beniamino; Redondo, Jose M.

    2015-04-01

    An important achievement in hydraulic engineering is the proposal and development of new techniques for the measurement of field velocities in hydraulic problems. The technological advances in digital cameras with high resolution and high speed found in the market, and the advances in digital image processing techniques now provides a tremendous potential to measure and study the behavior of the water surface flows. This technique was applied at the Laboratory of Hydraulics at the Technical University of Catalonia - Barcelona Tech to study the 2D velocity fields in the vicinity of a grate inlet. We used a platform to test grate inlets capacity with dimensions of 5.5 m long and 4 m wide allowing a zone of useful study of 5.5m x 3m, where the width is similar of the urban road lane. The platform allows you to modify the longitudinal slopes from 0% to 10% and transversal slope from 0% to 4%. Flow rates can arrive to 200 l/s. In addition a high resolution camera with 1280 x 1024 pixels resolution with maximum speed of 488 frames per second was used. A novel technique using particle image velocimetry to measure surface flow velocities has been developed and validated with the experimental data from the grate inlets capacity. In this case, the proposed methodology can become a useful tools to understand the velocity fields of the flow approaching the inlet where the traditional measuring equipment have serious problems and limitations. References DigiFlow User Guide. (2012), (June). Russo, B., Gómez, M., & Tellez, J. (2013). Methodology to Estimate the Hydraulic Efficiency of Nontested Continuous Transverse Grates. Journal of Irrigation and Drainage Engineering, 139(10), 864-871. doi:10.1061/(ASCE)IR.1943-4774.0000625 Teresa Vila (1), Jackson Tellez (1), Jesus Maria Sanchez (2), Laura Sotillos (1), Margarita Diez (3, 1), and J., & (1), M. R. (2014). Diffusion in fractal wakes and convective thermoelectric flows. Geophysical Research Abstracts - EGU General Assembly 2014

  16. A multi-time-step noise reduction method for measuring velocity statistics from particle tracking velocimetry

    Science.gov (United States)

    Machicoane, Nathanaël; López-Caballero, Miguel; Bourgoin, Mickael; Aliseda, Alberto; Volk, Romain

    2017-10-01

    We present a method to improve the accuracy of velocity measurements for fluid flow or particles immersed in it, based on a multi-time-step approach that allows for cancellation of noise in the velocity measurements. Improved velocity statistics, a critical element in turbulent flow measurements, can be computed from the combination of the velocity moments computed using standard particle tracking velocimetry (PTV) or particle image velocimetry (PIV) techniques for data sets that have been collected over different values of time intervals between images. This method produces Eulerian velocity fields and Lagrangian velocity statistics with much lower noise levels compared to standard PIV or PTV measurements, without the need of filtering and/or windowing. Particle displacement between two frames is computed for multiple different time-step values between frames in a canonical experiment of homogeneous isotropic turbulence. The second order velocity structure function of the flow is computed with the new method and compared to results from traditional measurement techniques in the literature. Increased accuracy is also demonstrated by comparing the dissipation rate of turbulent kinetic energy measured from this function against previously validated measurements.

  17. Measurements of the ultrasonic attenuation and velocity variation in neutron irradiated quartz for an intermediate dose of 2.6x1019 n/cm2

    International Nuclear Information System (INIS)

    Keppens, V.; Laermans, C.

    1992-01-01

    Ultrasonic measurements in neutron-irradiated quartz are carried out for an intermediate dose of 2.6x10 19 n/cm 2 . The variation of the velocity of sound has been measured and previous attenuation measurements are extended to temperatures below 1.2 K. The TS-parameters anti P and γ 1 are calculated from numerical fittings to the tunneling model. The obtained values continue the tendency of previous measurements for lower neutron doses, where a linear increase of anti P with the dose was found. This behaviour, however, is not followed by a higher dose, situated near the ''threshold regime''. (orig.)

  18. Temperature and velocity measurement fields of fluids using a schlieren system.

    Science.gov (United States)

    Martínez-González, Adrian; Guerrero-Viramontes, J A; Moreno-Hernández, David

    2012-06-01

    This paper proposes a combined method for two-dimensional temperature and velocity measurements in liquid and gas flow using a schlieren system. Temperature measurements are made by relating the intensity level of each pixel in a schlieren image to the corresponding knife-edge position measured at the exit focal plane of the schlieren system. The same schlieren images were also used to measure the velocity of the fluid flow. The measurement is made by using particle image velocimetry (PIV). The PIV software used in this work analyzes motion between consecutive schlieren frames to obtain velocity fields. The proposed technique was applied to measure the temperature and velocity fields in the natural convection of water provoked by a heated rectangular plate.

  19. Air temperature measurements based on the speed of sound to compensate long distance interferometric measurements

    Directory of Open Access Journals (Sweden)

    Astrua Milena

    2014-01-01

    Full Text Available A method to measure the real time temperature distribution along an interferometer path based on the propagation of acoustic waves is presented. It exploits the high sensitivity of the speed of sound in air to the air temperature. In particular, it takes advantage of a special set-up where the generation of the acoustic waves is synchronous with the amplitude modulation of a laser source. A photodetector converts the laser light to an electronic signal considered as reference, while the incoming acoustic waves are focused on a microphone and generate a second signal. In this condition, the phase difference between the two signals substantially depends on the temperature of the air volume interposed between the sources and the receivers. The comparison with the traditional temperature sensors highlighted the limit of the latter in case of fast temperature variations and the advantage of a measurement integrated along the optical path instead of a sampling measurement. The capability of the acoustic method to compensate the interferometric distance measurements due to air temperature variations has been demonstrated for distances up to 27 m.

  20. Using Smartphone Pressure Sensors to Measure Vertical Velocities of Elevators, Stairways, and Drones

    Science.gov (United States)

    Monteiro, Martín; Martí, Arturo C.

    2017-01-01

    We measure the vertical velocities of elevators, pedestrians climbing stairs, and drones (flying unmanned aerial vehicles), by means of smartphone pressure sensors. The barometric pressure obtained with the smartphone is related to the altitude of the device via the hydrostatic approximation. From the altitude values, vertical velocities are…

  1. A Fabry-Perot interferometer system for high-speed velocity measurement

    NARCIS (Netherlands)

    Cheng, L.K.; Bruinsma, A.J.A.; Prinse, W.C.; Smorenburg, C.

    1997-01-01

    The Fabry-Perot Velocity Interferometer System (F-PVIS) is designed and built for measuring the Doppler shift of light by recording positional changes in the interferometric pattern behind the Fabry-Perot interferometer. The velocity of a surface can be deduced from the Doppler shift which is caused

  2. Measurement of the burning velocity of propane-air mixtures using soap bubbles

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Yukio

    1988-12-20

    By filling a soap bubble with propane-air mixture of spacified equivalence ratio and by igniting it at the center, the flame propagation velocity was measured applying multiplex exposure Schlieren method. And the flow velocity of the unburnt propane-air mixture was also measured by a hot-wire anemometer. From the differences of the above two velocities, the burning velocity was obtained. The values of the burning velocity agreed well with the highly accurate results of usual measurements. The maximum value of the burning velocity, which exists at an equivalence ratio of 1.1, was 50cm/s. This value agreed well with the theoretical calculation result on the on-dimensional flame by Warnatz. The burning velocity in the range of from 0.7 to 1.5 equivalence ratios decreases symmetrically with the maximum value at the center. The velocity decrease in the excessive concentration range of fuel is only a little and converges between 7 and 10 cm/s. To evade the influence of the flame-front instability, measurements were done from 2 to 5cm from the ignition center. Thus accurate values were obtained. 23 refs., 5 figs.

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

    Science.gov (United States)

    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.)

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

    Science.gov (United States)

    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.

  5. Photon trajectories, anomalous velocities and weak measurements: a classical interpretation

    International Nuclear Information System (INIS)

    Bliokh, Konstantin Y; Kofman, Abraham G; Nori, Franco; Bekshaev, Aleksandr Y

    2013-01-01

    Recently, Kocsis et al (2011 Science 332 1170) reported the observation of ‘average trajectories of single photons’ in a two-slit interference experiment. This was possible by using the quantum weak-measurement method, which implies averaging over many events, i.e. in fact, a multi-photon limit of classical linear optics. We give a classical-optics interpretation of this experiment and other related problems. It appears that weak measurements of the local momentum of photons made by Kocsis et al represent measurements of the Poynting vector in an optical field. We consider both the real and imaginary parts of the local momentum and show that their measurements have been realized in classical optics using small-probe particles. We also examine the appearance of ‘anomalous’ values of the local momentum: either negative (backflow) or exceeding the wavenumber (superluminal propagation). These features appear to be closely related to vortices and evanescent waves. Finally, we revisit a number of older works and find examples of photon trajectories and anomalous-momentum measurements in various optical experiments. (paper)

  6. Evaluation of StereoPIV Measurement of Droplet Velocity in an Effervescent Spray

    Directory of Open Access Journals (Sweden)

    Sina Ghaemi

    2010-06-01

    Full Text Available Particle image velocimetry (PIV is a well known technique for measuring the instantaneous velocity field of flows. However, error may be introduced when measuring the velocity field of sprays using this technique when the spray droplets are used as the seed particles. In this study, the effect of droplet number density, droplet velocity profile, and droplet size distribution of a spray produced by an effervescent atomizer on velocity measurement using a StereoPIV has been investigated. A shadowgraph-particle tracking velocimetry (S-PTV system provided measurement of droplet size and velocity for comparison. This investigation demonstrated that the StereoPIV under-estimates velocity at near-field dense spray region where measurement accuracy is limited by multi-scattering of the laser sheet. In the dilute far-field region of the spray, StereoPIV measurement is mostly in agreement with velocity of the droplet size-class which is close to the mean diameter based on droplet number frequency times droplet cross sectional area.

  7. Speed of sound measurements of liquid C1–C4 alkanols

    International Nuclear Information System (INIS)

    Dávila, María J.; Gedanitz, Holger; Span, Roland

    2016-01-01

    Highlights: • Speeds of sound in alkanols were measured in a wide temperature and pressure range. • A pulse-echo method with a double path type sensor was employed. • A double polynomial equation was used to fit the experimental speed of sound data. • The accurate results were compared with available literature sources. - Abstract: Speed of sound measurements were made in methanol, ethanol, propan-1-ol, and butan-1-ol in the temperature range from (253.15 to 353.15) K at pressures up to 30 MPa by use of a pulse-echo method with a double path type sensor. The expanded overall uncertainty (k = 2) in speed of sound measurements are estimated to be 0.026% for methanol, 0.03% for ethanol, 0.013% for propan-1-ol and 0.01% for butan-1-ol. A double polynomial equation for the speed of sound with inputs of temperature and pressure has been fitted from the experimental results. These were compared with available literature sources and fundamental equations of state, showing good agreement among them to comparable alcohol purities and experimental uncertainties.

  8. Velocity Profile measurements in two-phase flow using multi-wave sensors

    Science.gov (United States)

    Biddinika, M. K.; Ito, D.; Takahashi, H.; Kikura, H.; Aritomi, M.

    2009-02-01

    Two-phase flow has been recognized as one of the most important phenomena in fluid dynamics. In addition, gas-liquid two-phase flow appears in various industrial fields such as chemical industries and power generations. In order to clarify the flow structure, some flow parameters have been measured by using many effective measurement techniques. The velocity profile as one of the important flow parameter, has been measured by using ultrasonic velocity profile (UVP) technique. This technique can measure velocity distributions along a measuring line, which is a beam formed by pulse ultrasounds. Furthermore, a multi-wave sensor can measure the velocity profiles of both gas and liquid phase using UVP method. In this study, two types of multi-wave sensors are used. A sensor has cylindrical shape, and another one has square shape. The piezoelectric elements of each sensor have basic frequencies of 8 MHz for liquid phase and 2 MHz for gas phase, separately. The velocity profiles of air-water bubbly flow in a vertical rectangular channel were measured by using these multi-wave sensors, and the validation of the measuring accuracy was performed by the comparison between the velocity profiles measured by two multi-wave sensors.

  9. Velocity Profile measurements in two-phase flow using multi-wave sensors

    International Nuclear Information System (INIS)

    Biddinika, M K; Ito, D; Takahashi, H; Kikura, H; Aritomi, M

    2009-01-01

    Two-phase flow has been recognized as one of the most important phenomena in fluid dynamics. In addition, gas-liquid two-phase flow appears in various industrial fields such as chemical industries and power generations. In order to clarify the flow structure, some flow parameters have been measured by using many effective measurement techniques. The velocity profile as one of the important flow parameter, has been measured by using ultrasonic velocity profile (UVP) technique. This technique can measure velocity distributions along a measuring line, which is a beam formed by pulse ultrasounds. Furthermore, a multi-wave sensor can measure the velocity profiles of both gas and liquid phase using UVP method. In this study, two types of multi-wave sensors are used. A sensor has cylindrical shape, and another one has square shape. The piezoelectric elements of each sensor have basic frequencies of 8 MHz for liquid phase and 2 MHz for gas phase, separately. The velocity profiles of air-water bubbly flow in a vertical rectangular channel were measured by using these multi-wave sensors, and the validation of the measuring accuracy was performed by the comparison between the velocity profiles measured by two multi-wave sensors.

  10. Improved flow velocity estimates from moving-boat ADCP measurements

    NARCIS (Netherlands)

    Vermeulen, B.; Hoitink, A.J.F.; Sassi, M.G.

    2014-01-01

    Acoustic Doppler current profilers (ADCPs) are the current standard for flow measurements in large-scale open water systems. Existing techniques to process vessel-mounted ADCP data assume homogeneous or linearly changing flow between the acoustic beams. This assumption is likely to fail but is

  11. Improved flow velocity estmates from oving-boat ADCO measurements

    NARCIS (Netherlands)

    Vermeulen, B.; Sassi, M.G.; Hoitink, A.J.F.

    2014-01-01

    Acoustic Doppler current profilers (ADCPs) are the current standard for flow measurements in large-scale open water systems. Existing techniques to process vessel-mounted ADCP data assume homogeneous or linearly changing flow between the acoustic beams. This assumption is likely to fail but is

  12. Measurement of longitudinal and rayleigh wave velocities by advanced one-sided technique in concrete

    International Nuclear Information System (INIS)

    Lee, Joon Hyun; Song, Won Joon; Popovics, J. S.; Achenbach, J. D.

    1997-01-01

    A new procedure for the advanced one-sided measurement of longitudinal wave and surface wave velocities in concrete is presented in this paper. Stress waves are generated in a consistent fashion with a DC solenoid. Two piezoelectric accelerometers are mounted on the surface of a specimen as receivers. Stress waves propagate along the surface of the specimen and are detected by the receivers. In order to reduce the large incoherent noise levels of the signals, signals are collected and manipulated by a computer program for each velocity measurement. For a known distance between the two receivers and using the measured flight times, the velocities of the longitudinal wave and the surface wave are measured. The velocities of the longitudinal wave determined by this method are compared with those measured by conventional methods on concrete, PMMA and steel.

  13. Measurements of anisotropic sound propagation in glass wool

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    2000-01-01

    to the glass wool sheets was 75 dB/m, and for propagation parallel with the sheets 57 dB/m. For mass density 30 kg/m3, the corresponding numbers were 140 and 100 dB/m. The measured values were compared with calculated ones taking into account the movements of the fiber skeleton. The calculations need...

  14. Measurement of lithium target surface velocity in the IFMIF/EVEDA lithium test loop

    Energy Technology Data Exchange (ETDEWEB)

    Kanemura, Takuji, E-mail: kanemura.takuji@jaea.go.jp [Japan Atomic Energy Agency, 4002 Narita, O-arai, Higashi-Ibaraki-gun, Ibaraki 311-1393 (Japan); Kondo, Hiroo; Furukawa, Tomohiro; Hirakawa, Yasushi [Japan Atomic Energy Agency, 4002 Narita, O-arai, Higashi-Ibaraki-gun, Ibaraki 311-1393 (Japan); Hoashi, Eiji [Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Yoshihashi, Sachiko; Horiike, Hiroshi [Fukui University of Technology, Gakuen 3-6-1, Fukui-shi, Fukui 910-8505 (Japan); Wakai, Eiichi [Japan Atomic Energy Agency, 4002 Narita, O-arai, Higashi-Ibaraki-gun, Ibaraki 311-1393 (Japan)

    2016-11-01

    Highlights: • The objective is to measure the free-surface velocity field of the IFMIF Li target. • The Li target has an important role to remove 10 MW heat input from a deuteron beam. • The free-surface of the Li target is under the most severe heat load condition. • Measured surface velocities are almost equal to cross-sectional average velocities. • It was confirmed that the IFMIF Li target has adequate heat removal performance. - Abstract: In the framework of the Engineering Validation and Engineering Design Activities (EVEDA) project of the International Fusion Materials Irradiation Facility (IFMIF), we measured surface velocity fields of a lithium (Li) target at the EVEDA Li test loop under specifically-designated IFMIF conditions (target speeds of 10, 15, and 20 m/s, vacuum pressure of 10{sup −3} Pa, and Li temperature of 250 °C). In the current design of the IFMIF, the free surface of the Li target is under a most severe heat load condition with respect to Li boiling. The objective of this study is to measure the actual free-surface velocity under these IFMIF conditions to evaluate the heat removal performance of the Li target. The measured results (using the surface-wave tracking method that our team developed) showed two-dimensional time-averaged velocity distributions around the IFMIF beam footprint being virtually uniform, and close to the cross-sectional average velocity. The uniformity of the velocity distributions was less than 1 m/s. The comparison between the measured and analyzed surface velocity at the beam center showed that the analysis accurately predicts the measurement results within a margin of 3%. Finally, it was confirmed that the Li target delivers adequate heat removal performance in the IFMIF as designed.

  15. Laser-induced fluorescence measurements of argon ion velocities near the sheath boundary of an argon-xenon plasma

    International Nuclear Information System (INIS)

    Lee, Dongsoo; Severn, Greg; Oksuz, Lutfi; Hershkowitz, Noah

    2006-01-01

    The Bohm sheath criterion in single- and two-ion species plasma is studied with laser-induced fluorescence using a diode laser. Xenon is added to a low pressure unmagnetized dc hot filament argon discharge confined by surface multidipole magnetic fields. The Ar II transition at 668.614 nm is adopted for optical pumping to detect the fluorescence from the plasma and to measure the argon ion velocity distribution functions with respect to positions relative to a negatively biased boundary plate. The structures of the plasma sheath and presheath are measured by an emissive probe. The ion concentrations of the two-species in the bulk plasma are calculated from ion acoustic wave experiments. Results are compared with previous experiments of Ar-He plasmas in which the argon ions were the heavier ion species. Unlike the previous results, the argon speed is slower than its own Bohm velocity near the sheath-presheath boundary in the Ar-Xe plasma where argon ions are the lighter ion species. We argue that this result is consistent with the behaviour of the helium ion required by the generalized Bohm criterion in the previous experiments with Ar-He plasmas. Further, our results suggest that the measured argon ion speed approaches the ion sound speed of the system

  16. Convection measurement package for space processing sounding rocket flights. [low gravity manufacturing - fluid dynamics

    Science.gov (United States)

    Spradley, L. W.

    1975-01-01

    The effects on heated fluids of nonconstant accelerations, rocket vibrations, and spin rates, was studied. A system is discussed which can determine the influence of the convective effects on fluid experiments. The general suitability of sounding rockets for performing these experiments is treated. An analytical investigation of convection in an enclosure which is heated in low gravity is examined. The gravitational body force was taken as a time-varying function using anticipated sounding rocket accelerations, since accelerometer flight data were not available. A computer program was used to calculate the flow rates and heat transfer in fluids with geometries and boundary conditions typical of space processing configurations. Results of the analytical investigation identify the configurations, fluids and boundary values which are most suitable for measuring the convective environment of sounding rockets. A short description of fabricated fluid cells and the convection measurement package is given. Photographs are included.

  17. Measurement and classification of heart and lung sounds by using LabView for educational use.

    Science.gov (United States)

    Altrabsheh, B

    2010-01-01

    This study presents the design, development and implementation of a simple low-cost method of phonocardiography signal detection. Human heart and lung signals are detected by using a simple microphone through a personal computer; the signals are recorded and analysed using LabView software. Amplitude and frequency analyses are carried out for various phonocardiography pathological cases. Methods for automatic classification of normal and abnormal heart sounds, murmurs and lung sounds are presented. Various cases of heart and lung sound measurement are recorded and analysed. The measurements can be saved for further analysis. The method in this study can be used by doctors as a detection tool aid and may be useful for teaching purposes at medical and nursing schools.

  18. New Interpretations of Measured Antihydrogen Velocities and Field Ionization Spectra

    International Nuclear Information System (INIS)

    Pohl, T.; Sadeghpour, H. R.; Gabrielse, G.

    2006-01-01

    We present extensive Monte Carlo simulations, showing that cold antihydrogen (H) atoms are produced when antiprotons (p) are gently heated in the side wells of a nested Penning trap. The observed H with high energies, that had seemed to indicate otherwise, are instead explained by a surprisingly effective charge-exchange mechanism. We shed light on the previously measured field-ionization spectrum, and reproduce both the characteristic low-field power law as well as the enhanced H production at higher fields. The latter feature is shown to arise from H atoms too deeply bound to be described as guiding center atoms, atoms with internally chaotic motion

  19. Magnetic particle imaging for in vivo blood flow velocity measurements in mice

    Science.gov (United States)

    Kaul, Michael G.; Salamon, Johannes; Knopp, Tobias; Ittrich, Harald; Adam, Gerhard; Weller, Horst; Jung, Caroline

    2018-03-01

    Magnetic particle imaging (MPI) is a new imaging technology. It is a potential candidate to be used for angiographic purposes, to study perfusion and cell migration. The aim of this work was to measure velocities of the flowing blood in the inferior vena cava of mice, using MPI, and to evaluate it in comparison with magnetic resonance imaging (MRI). A phantom mimicking the flow within the inferior vena cava with velocities of up to 21 cm s‑1 was used for the evaluation of the applied analysis techniques. Time–density and distance–density analyses for bolus tracking were performed to calculate flow velocities. These findings were compared with the calibrated velocities set by a flow pump, and it can be concluded that velocities of up to 21 cm s‑1 can be measured by MPI. A time–density analysis using an arrival time estimation algorithm showed the best agreement with the preset velocities. In vivo measurements were performed in healthy FVB mice (n  =  10). MRI experiments were performed using phase contrast (PC) for velocity mapping. For MPI measurements, a standardized injection of a superparamagnetic iron oxide tracer was applied. In vivo MPI data were evaluated by a time–density analysis and compared to PC MRI. A Bland–Altman analysis revealed good agreement between the in vivo velocities acquired by MRI of 4.0  ±  1.5 cm s‑1 and those measured by MPI of 4.8  ±  1.1 cm s‑1. Magnetic particle imaging is a new tool with which to measure and quantify flow velocities. It is fast, radiation-free, and produces 3D images. It therefore offers the potential for vascular imaging.

  20. A Data-Driven Approach to Develop Physically Sound Predictors: Application to Depth-Averaged Velocities and Drag Coefficients on Vegetated Flows

    Science.gov (United States)

    Tinoco, R. O.; Goldstein, E. B.; Coco, G.

    2016-12-01

    We use a machine learning approach to seek accurate, physically sound predictors, to estimate two relevant flow parameters for open-channel vegetated flows: mean velocities and drag coefficients. A genetic programming algorithm is used to find a robust relationship between properties of the vegetation and flow parameters. We use data published from several laboratory experiments covering a broad range of conditions to obtain: a) in the case of mean flow, an equation that matches the accuracy of other predictors from recent literature while showing a less complex structure, and b) for drag coefficients, a predictor that relies on both single element and array parameters. We investigate different criteria for dataset size and data selection to evaluate their impact on the resulting predictor, as well as simple strategies to obtain only dimensionally consistent equations, and avoid the need for dimensional coefficients. The results show that a proper methodology can deliver physically sound models representative of the processes involved, such that genetic programming and machine learning techniques can be used as powerful tools to study complicated phenomena and develop not only purely empirical, but "hybrid" models, coupling results from machine learning methodologies into physics-based models.

  1. The sound power measurement and certification of wind turbines

    International Nuclear Information System (INIS)

    MacKinnon, A.; Henderson, R.

    1992-01-01

    It is anticipated that there will be a substantial growth in the exploitation of renewable energy from the wind over the next few years. A major factor in this expected growth is the environmental acceptance or otherwise of wind turbines and in particular their acoustic characteristics. It is generally accepted within the turbine community that reliable methods of measuring and quantifying a turbine's acoustic signature are essential if this exploitation is to be realised. This paper will seek to review current practice both in the UK and further afield and will describe the development of a practical and reliable test method, which will aid the wind turbine Manufacturer, Developer and Planner. (author)

  2. Theoretical analysis of stack gas emission velocity measurement by optical scintillation

    International Nuclear Information System (INIS)

    Yang Yang; Dong Feng-Zhong; Ni Zhi-Bo; Pang Tao; Zeng Zong-Yong; Wu Bian; Zhang Zhi-Rong

    2014-01-01

    Theoretical analysis for an online measurement of the stack gas flow velocity based on the optical scintillation method with a structure of two parallel optical paths is performed. The causes of optical scintillation in a stack are first introduced. Then, the principle of flow velocity measurement and its mathematical expression based on cross correlation of the optical scintillation are presented. The field test results show that the flow velocity measured by the proposed technique in this article is consistent with the value tested by the Pitot tube. It verifies the effectiveness of this method. Finally, by use of the structure function of logarithmic light intensity fluctuations, the theoretical explanation of optical scintillation spectral characteristic in low frequency is given. The analysis of the optical scintillation spectrum provides the basis for the measurement of the stack gas flow velocity and particle concentration simultaneously. (general)

  3. ALADIN: an atmospheric laser Doppler wind lidar instrument for wind velocity measurements from space

    Science.gov (United States)

    Krawczyk, R.; Ghibaudo, JB.; Labandibar, JY.; Willetts, D.; Vaughan, M.; Pearson, G.; Harris, M.; Flamant, P. H.; Salamitou, P.; Dabas, A.; Charasse, R.; Midavaine, T.; Royer, M.; Heimel, H.

    2018-04-01

    This paper, "ALADIN: an atmospheric laser Doppler wind lidar instrument for wind velocity measurements from space," was presented as part of International Conference on Space Optics—ICSO 1997, held in Toulouse, France.

  4. A Balloon Sounding Technique for Measuring SO2 Plumes

    Science.gov (United States)

    Morris, Gary A.; Komhyr, Walter D.; Hirokawa, Jun; Lefer, Barry; Krotkov, Nicholay; Ngan, Fong

    2010-01-01

    This paper reports on the development of a new technique for inexpensive measurements of SO2 profiles using a modified dual-ozonesonde instrument payload. The presence of SO2 interferes with the standard electrochemical cell (ECC) ozonesonde measurement, resulting in -1 molecule of O3 reported for each molecule of SO2 present (provided [O3] > [SO2]). In laboratory tests, an SO2 filter made with Cr03 placed on the inlet side of the sonde removes nearly 100% of the SO2 present for concentrations up to 60 ppbv and remained effective after exposure to 2.8 X 10(exp 16) molecules of SO2 [equivalent to a column approximately 150 DU (1 DU = 2.69 X 10(exp 20) molecules m(exp -2))]. Flying two ECC instruments on the same payload with one filtered and the other unfiltered yields SO2 profiles, inferred by subtraction. Laboratory tests and field experience suggest an SO2 detection limit of approximately 3 pbb with profiles valid from the surface to the ozonopause [i.e., approximately (8-10 km)]. Two example profiles demonstrate the success of this technique for both volcanic and industrial plumes.

  5. Measurement of fast-changing low velocities by photonic Doppler velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Song Hongwei; Wu Xianqian; Huang Chenguang; Wei Yangpeng; Wang Xi [Key Laboratory for Hydrodynamics and Ocean Engineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China)

    2012-07-15

    Despite the increasing popularity of photonic Doppler velocimetry (PDV) in shock wave experiments, its capability of capturing low particle velocities while changing rapidly is still questionable. The paper discusses the performance of short time Fourier transform (STFT) and continuous wavelet transform (CWT) in processing fringe signals of fast-changing low velocities measured by PDV. Two typical experiments are carried out to evaluate the performance. In the laser shock peening test, the CWT gives a better interpretation to the free surface velocity history, where the elastic precursor, main plastic wave, and elastic release wave can be clearly identified. The velocities of stress waves, Hugoniot elastic limit, and the amplitude of shock pressure induced by laser can be obtained from the measurement. In the Kolsky-bar based tests, both methods show validity of processing the longitudinal velocity signal of incident bar, whereas CWT improperly interprets the radial velocity of the shocked sample at the beginning period, indicating the sensitiveness of the CWT to the background noise. STFT is relatively robust in extracting waveforms of low signal-to-noise ratio. Data processing method greatly affects the temporal resolution and velocity resolution of a given fringe signal, usually CWT demonstrates a better local temporal resolution and velocity resolution, due to its adaptability to the local frequency, also due to the finer time-frequency product according to the uncertainty principle.

  6. Precise measurement of velocity dependent friction in rotational motion

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Junaid; Hassan, Hafsa; Shamim, Sohaib; Mahmood, Waqas; Anwar, Muhammad Sabieh, E-mail: sabieh@lums.edu.pk [School of Science and Engineering, Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A, Lahore 54792 (Pakistan)

    2011-09-15

    Frictional losses are experimentally determined for a uniform circular disc exhibiting rotational motion. The clockwise and anticlockwise rotations of the disc, that result when a hanger tied to a thread is released from a certain height, give rise to vertical oscillations of the hanger as the thread winds and unwinds over a pulley attached to the disc. It is thus observed how the maximum height is achieved by the hanger decrements in every bounce. From the decrements, the rotational frictional losses are measured. The precision is enhanced by correlating vertical motion with the angular motion. This method leads to a substantial improvement in precision. Furthermore, the frictional torque is shown to be proportional to the angular speed. The experiment has been successfully employed in the undergraduate lab setting.

  7. Recent results from the ICARUS experiment - Measurements concerning neutrino velocity

    International Nuclear Information System (INIS)

    Cieslik, K.

    2014-01-01

    The ICARUS T600 detector at the LNGS Gran Sasso underground Laboratory is the first large mass Liquid Argon Time Projection Chamber (LAr-TPC) designed to study the ν μ → ν τ oscillation for neutrinos from the CERN-CNGS beam, the atmospheric neutrinos and matter stability. In stable conditions the detector has been collecting data since October 2010. The results, presented here, of the search for analogue to the Cherenkov radiation at superluminal speeds and the measurement of the neutrino time of flight are incompatible with the OPERA collaboration claiming that CNGS muon neutrinos arrive to Gran Sasso, after covering a distance of about 732 km, earlier than expected from the luminal speed. (author)

  8. Group velocity measurement using spectral interference in near-field scanning optical microscopy

    International Nuclear Information System (INIS)

    Mills, John D.; Chaipiboonwong, Tipsuda; Brocklesby, William S.; Charlton, Martin D. B.; Netti, Caterina; Zoorob, Majd E.; Baumberg, Jeremy J.

    2006-01-01

    Near-field scanning optical microscopy provides a tool for studying the behavior of optical fields inside waveguides. In this experiment the authors measure directly the variation of group velocity between different modes of a planar slab waveguide as the modes propagate along the guide. The measurement is made using the spectral interference between pulses propagating inside the waveguide with different group velocities, collected using a near-field scanning optical microscope at different points down the guide and spectrally resolved. The results are compared to models of group velocities in simple guides

  9. Acoustics. Measurement of sound insulation in buildings and of building elements. Laboratory measurements of the reduction of transmitted impact noise by floor coverings on a heavyweight standard floor

    CERN Document Server

    British Standards Institution. London

    1998-01-01

    Acoustics. Measurement of sound insulation in buildings and of building elements. Laboratory measurements of the reduction of transmitted impact noise by floor coverings on a heavyweight standard floor

  10. Measurements of auroral particles by means of sounding rockets of mother-daughter type

    International Nuclear Information System (INIS)

    Falck, A.

    1985-11-01

    The scientific objective of the S17 payloads was to study the ionosphere during auroral situations and especially with regards to the local fine structure and a possible separation of spatial and temporal variations of auroral phenomena. The intensities of 8 keV and 2 keV electrons have been measured from one sounding rocket launched into a breakup aurora of moderate activity and from another rocket launched into a very active substorm situation. Both the rockets were of mother-daughter type i.e. had two separated payloads. The general features in the data of different particle energies were very similar over the whole flight time of the rockets. Special events and gradients and well identifiable shapes in the particle intensities were studied to see if the intensity fluctuations obtained from two detectors in one payload or from detectors into separate payloads were time delayed. Such time delays in the particle flux intensities were obvious in both of the rocket measurements and most of these time shifts could be understood as caused by spatial variations in the particle precipitation. In parts of the rocket flights the particle intensity variations were true temporal changes. The time lags between 8 keV and 2 keV electron intensities detected in the same payload, which could be observed and were obtained by crosscorrelation analyses, were in the range less than 0.3 s and most of them less than 0.1 s. If the time differences are assumed to be caused by the velocity dispersion of the particles, the particle data reported here placed the modulation source at a distance of less than 10 000 km from the rocket position. Measurements at the S17-1 mother payload of the electric field have been compared with data of precipitating electrons and low-light-level-TV-recording of the auroral situation. An inverted-V precipitation event was observed and was associated with auroral arcs and with reversals of the measured electric field components implicating the possibility of

  11. Variation of the Korotkoff Stethoscope Sounds During Blood Pressure Measurement: Analysis Using a Convolutional Neural Network.

    Science.gov (United States)

    Pan, Fan; He, Peiyu; Liu, Chengyu; Li, Taiyong; Murray, Alan; Zheng, Dingchang

    2017-11-01

    Korotkoff sounds are known to change their characteristics during blood pressure (BP) measurement, resulting in some uncertainties for systolic and diastolic pressure (SBP and DBP) determinations. The aim of this study was to assess the variation of Korotkoff sounds during BP measurement by examining all stethoscope sounds associated with each heartbeat from above systole to below diastole during linear cuff deflation. Three repeat BP measurements were taken from 140 healthy subjects (age 21 to 73 years; 62 female and 78 male) by a trained observer, giving 420 measurements. During the BP measurements, the cuff pressure and stethoscope signals were simultaneously recorded digitally to a computer for subsequent analysis. Heartbeats were identified from the oscillometric cuff pressure pulses. The presence of each beat was used to create a time window (1 s, 2000 samples) centered on the oscillometric pulse peak for extracting beat-by-beat stethoscope sounds. A time-frequency two-dimensional matrix was obtained for the stethoscope sounds associated with each beat, and all beats between the manually determined SBPs and DBPs were labeled as "Korotkoff." A convolutional neural network was then used to analyze consistency in sound patterns that were associated with Korotkoff sounds. A 10-fold cross-validation strategy was applied to the stethoscope sounds from all 140 subjects, with the data from ten groups of 14 subjects being analyzed separately, allowing consistency to be evaluated between groups. Next, within-subject variation of the Korotkoff sounds analyzed from the three repeats was quantified, separately for each stethoscope sound beat. There was consistency between folds with no significant differences between groups of 14 subjects (P = 0.09 to P = 0.62). Our results showed that 80.7% beats at SBP and 69.5% at DBP were analyzed as Korotkoff sounds, with significant differences between adjacent beats at systole (13.1%, P = 0.001) and diastole (17.4%, P < 0

  12. Measurement of two-dimensional bubble velocity by Using tri-fiber-optical Probe

    International Nuclear Information System (INIS)

    Yang Ruichang; Zheng Rongchuan; Zhou Fanling; Liu Ruolei

    2009-01-01

    In this study, an advanced measuring system with a tri-single-fiber-optical-probe has been developed to measure two-dimensional vapor/gas bubble velocity. The use of beam splitting devices instead of beam splitting lens simplifies the optical system, so the system becomes more compact and economic, and more easy to adjust. Corresponding to using triple-optical probe for measuring two-dimensional bubble velocity, a data processing method has been developed, including processing of bubble signals, cancelling of unrelated signals, determining of bubble velocity with cross correlation technique and so on. Using the developed two-dimensional bubble velocity measuring method, the rising velocity of air bubbles in gravitational field was measured. The measured bubble velocities were compared with the empirical correlation available. Deviation was in the range of ±30%. The bubble diameter obtained by data processing is in good accordance with that observed with a synchro-scope and a camera. This shows that the method developed here is reliable.

  13. Energy Demodulation Algorithm for Flow Velocity Measurement of Oil-Gas-Water Three-Phase Flow

    Directory of Open Access Journals (Sweden)

    Yingwei Li

    2014-01-01

    Full Text Available Flow velocity measurement was an important research of oil-gas-water three-phase flow parameter measurements. In order to satisfy the increasing demands for flow detection technology, the paper presented a gas-liquid phase flow velocity measurement method which was based on energy demodulation algorithm combing with time delay estimation technology. First, a gas-liquid phase separation method of oil-gas-water three-phase flow based on energy demodulation algorithm and blind signal separation technology was proposed. The separation of oil-gas-water three-phase signals which were sampled by conductance sensor performed well, so the gas-phase signal and the liquid-phase signal were obtained. Second, we used the time delay estimation technology to get the delay time of gas-phase signals and liquid-phase signals, respectively, and the gas-phase velocity and the liquid-phase velocity were derived. At last, the experiment was performed at oil-gas-water three-phase flow loop, and the results indicated that the measurement errors met the need of velocity measurement. So it provided a feasible method for gas-liquid phase velocity measurement of the oil-gas-water three-phase flow.

  14. Diode Laser Velocity Measurements by Modulated Filtered Rayleigh Scattering

    Science.gov (United States)

    Mach, J. J.; Varghese, P. L.; Jagodzinski, J. J.

    1999-01-01

    The ability of solid-state lasers to be tuned in operating frequency at MHz rates by input current modulation, while maintaining a relatively narrow line-width, has made them useful for spectroscopic measurements. Their other advantages include low cost, reliability, durability, compact size, and modest power requirements, making them a good choice for a laser source in micro-gravity experiments in drop-towers and in flight. For their size, they are also very bright. In a filtered Rayleigh scattering (FRS) experiment, a diode laser can be used to scan across an atomic or molecular absorption line, generating large changes in transmission at the resonances for very small changes in frequency. The hyperfine structure components of atomic lines of alkali metal vapors are closely spaced and very strong, which makes such atomic filters excellent candidates for sensitive Doppler shift detection and therefore for high-resolution velocimetry. In the work we describe here we use a Rubidium vapor filter, and work with the strong D(sub 2) transitions at 780 nm that are conveniently accessed by near infrared diode lasers. The low power output of infrared laser diodes is their primary drawback relative to other laser systems commonly used for velocimetry. However, the capability to modulate the laser frequency rapidly and continuously helps mitigate this. Using modulation spectroscopy and a heterodyne detection scheme with a lock-in amplifier, one can extract sub-microvolt signals occurring at a specific frequency from a background that is orders of magnitude stronger. The diode laser modulation is simply achieved by adding a small current modulation to the laser bias current. It may also be swept repetitively in wavelength using an additional lower frequency current ramp.

  15. Front-Crawl Instantaneous Velocity Estimation Using a Wearable Inertial Measurement Unit

    Directory of Open Access Journals (Sweden)

    Kamiar Aminian

    2012-09-01

    Full Text Available Monitoring the performance is a crucial task for elite sports during both training and competition. Velocity is the key parameter of performance in swimming, but swimming performance evaluation remains immature due to the complexities of measurements in water. The purpose of this study is to use a single inertial measurement unit (IMU to estimate front crawl velocity. Thirty swimmers, equipped with an IMU on the sacrum, each performed four different velocity trials of 25 m in ascending order. A tethered speedometer was used as the velocity measurement reference. Deployment of biomechanical constraints of front crawl locomotion and change detection framework on acceleration signal paved the way for a drift-free integration of forward acceleration using IMU to estimate the swimmers velocity. A difference of 0.6 ± 5.4 cm·s−1 on mean cycle velocity and an RMS difference of 11.3 cm·s−1 in instantaneous velocity estimation were observed between IMU and the reference. The most important contribution of the study is a new practical tool for objective evaluation of swimming performance. A single body-worn IMU provides timely feedback for coaches and sport scientists without any complicated setup or restraining the swimmer’s natural technique.

  16. Hybrid method for determining the parameters of condenser microphones from measured membrane velocities and numerical calculations

    DEFF Research Database (Denmark)

    Barrera Figueroa, Salvador; Rasmussen, Knud; Jacobsen, Finn

    2009-01-01

    to this problem is to measure the velocity distribution of the membrane by means of a non-contact method, such as laser vibrometry. The measured velocity distribution can be used together with a numerical formulation such as the boundary element method for estimating the microphone response and other parameters......, e.g., the acoustic center. In this work, such a hybrid method is presented and examined. The velocity distributions of a number of condenser microphones have been determined using a laser vibrometer, and these measured velocity distributions have been used for estimating microphone responses......Typically, numerical calculations of the pressure, free-field, and random-incidence response of a condenser microphone are carried out on the basis of an assumed displacement distribution of the diaphragm of the microphone; the conventional assumption is that the displacement follows a Bessel...

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

    Science.gov (United States)

    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.

  18. Artifact rejection of distortion product otoacoustic emissions measured after sound exposure

    DEFF Research Database (Denmark)

    Reuter, Karen; Ordoñez, Rodrigo Pizarro; de Toro, Miguel Angel Aranda

    2007-01-01

    In a previous study [3] distortion product otoacoustic emissions (DPOAEs) were measured both before and after a moderate sound exposure, which caused a reduction of DPOAE levels. After the exposure DPOAEs had often levels below the noise floor. In the present paper it is discussed, whether...

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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…

  1. Implementation and effectiveness of sound mitigation measures on Texas highways (HB 790) : final report.

    Science.gov (United States)

    2016-10-01

    The 84th Texas Legislature passed House Bill (HB) 790 directing the Texas A&M Transportation Institute (TTI) to perform a study on the implementation and effectiveness of sound mitigation measures on the state highway system and certain toll roads an...

  2. Making Ultraviolet Spectro-Polarimetry Polarization Measurements with the MSFC Solar Ultraviolet Magnetograph Sounding Rocket

    Science.gov (United States)

    West, Edward; Cirtain, Jonathan; Kobayashi, Ken; Davis, John; Gary, Allen

    2011-01-01

    This paper will describe the Marshall Space Flight Center's Solar Ultraviolet Magnetograph Investigation (SUMI) sounding rocket program. This paper will concentrate on SUMI's VUV optics, and discuss their spectral, spatial and polarization characteristics. While SUMI's first flight (7/30/2010) met all of its mission success criteria, there are several areas that will be improved for its second and third flights. This paper will emphasize the MgII linear polarization measurements and describe the changes that will be made to the sounding rocket and how those changes will improve the scientific data acquired by SUMI.

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

    Science.gov (United States)

    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.

  4. Pressure sound level measurements at an educational environment in Goiania, Goias, Brazil

    International Nuclear Information System (INIS)

    Costa, Jhonatha J.L.; Nascimento, Eriberto O. do; Oliveira, Lucas N. de; Caldas, Linda V. E.

    2017-01-01

    In this work, twenty five points located on the ground floor of the Federal Institute of Education, Science and Technology of Goias - IFG - Campus Goiania, were analyzed in morning periods of two Saturdays. The pressure sound levels were measured at internal and external environments during routine activities seeking to perform an environmental monitoring at this institution. The initial hypothesis was that an amusement park (Mutirama Park) was responsible for originating noise pollution in the institution, but the results showed, within the campus environment, sound pressure levels in accordance with the Municipal legislation of Goiania for all points. (author)

  5. Pressure sound level measurements at an educational environment in Goiania, Goias, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Jhonatha J.L.; Nascimento, Eriberto O. do; Oliveira, Lucas N. de [Instituto Federal de Educação, Ciência e Tecnologia de Goiás (IFG), Goiânia, GO (Brazil); Caldas, Linda V. E., E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    In this work, twenty five points located on the ground floor of the Federal Institute of Education, Science and Technology of Goias - IFG - Campus Goiania, were analyzed in morning periods of two Saturdays. The pressure sound levels were measured at internal and external environments during routine activities seeking to perform an environmental monitoring at this institution. The initial hypothesis was that an amusement park (Mutirama Park) was responsible for originating noise pollution in the institution, but the results showed, within the campus environment, sound pressure levels in accordance with the Municipal legislation of Goiania for all points. (author)

  6. Comparison of shear-wave velocity measurements by crosshole, downhole and seismic cone penetration test methods

    Energy Technology Data Exchange (ETDEWEB)

    Suthaker, N.; Tweedie, R. [Thurber Engineering Ltd., Edmonton, AB (Canada)

    2009-07-01

    Shear wave velocity measurements are an integral part of geotechnical studies for major structures and are an important tool in their design for site specific conditions such as site-specific earthquake response. This paper reported on a study in which shear wave velocities were measured at a proposed petrochemical plant site near Edmonton, Alberta. The proposed site is underlain by lacustrine clay, glacial till and upper Cretaceous clay shale and sandstone bedrock. The most commonly used methods for determining shear wave velocity include crosshole seismic tests, downhole seismic tests, and seismic cone penetration tests (SCPT). This paper presented the results of all 3 methods used in this study and provided a comparison of the various test methods and their limitations. The crosshole test results demonstrated a common trend of increasing shear wave velocity with depth to about 15 m, below which the velocities remained relatively constant. An anomaly was noted at one site, where the shear wave velocity was reduced at a zone corresponding to clay till containing stiff high plastic clay layers. The field study demonstrated that reasonable agreement in shear wave velocity measurements can be made using crosshole, downhole and seismic tests in the same soil conditions. The National Building Code states that the shear wave velocity is the fundamental method for determining site classification, thus emphasizing the importance of obtaining shear wave velocity measurements for site classification. It was concluded that an SCPT program can be incorporated into the field program without much increase in cost and can be supplemented by downhole or crosshole techniques. 5 refs., 2 tabs., 10 figs.

  7. A novel method for direct localized sound speed measurement using the virtual source paradigm

    DEFF Research Database (Denmark)

    Byram, Brett; Trahey, Gregg E.; Jensen, Jørgen Arendt

    2007-01-01

    ) mediums. The inhomogeneous mediums were arranged as an oil layer, one 6 mm thick and the other 11 mm thick, on top of a water layer. To complement the phantom studies, sources of error for spatial registration of virtual detectors were simulated. The sources of error presented here are multiple sound...... registered virtual detector. Between a pair of registered virtual detectors a spherical wave is propagated. By beamforming the received 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 used...... both phantom and simulation results. The phantom consisted of two wire targets located near the transducer's axis at depths of 17 and 28 mm. Using this phantom the sound speed between the wires was measured for a homogeneous (water) medium and for two inhomogeneous (DB-grade castor oil and water...

  8. Implication of Broadband Dispersion Measurements in Constraining Upper Mantle Velocity Structures

    Science.gov (United States)

    Kuponiyi, A.; Kao, H.; Cassidy, J. F.; Darbyshire, F. A.; Dosso, S. E.; Gosselin, J. M.; Spence, G.

    2017-12-01

    Dispersion measurements from earthquake (EQ) data are traditionally inverted to obtain 1-D shear-wave velocity models, which provide information on deep earth structures. However, in many cases, EQ-derived dispersion measurements lack short-period information, which theoretically should provide details of shallow structures. We show that in at least some cases short-period information, such as can be obtained from ambient seismic noise (ASN) processing, must be combined with EQ dispersion measurements to properly constrain deeper (e.g. upper-mantle) structures. To verify this, synthetic dispersion data are generated using hypothetical velocity models under four scenarios: EQ only (with and without deep low-velocity layers) and combined EQ and ASN data (with and without deep low-velocity layers). The now "broadband" dispersion data are inverted using a trans-dimensional Bayesian framework with the aim of recovering the initial velocity models and assessing uncertainties. Our results show that the deep low-velocity layer could only be recovered from the inversion of the combined ASN-EQ dispersion measurements. Given this result, we proceed to describe a method for obtaining reliable broadband dispersion measurements from both ASN and EQ and show examples for real data. The implication of this study in the characterization of lithospheric and upper mantle structures, such as the Lithosphere-Asthenosphere Boundary (LAB), is also discussed.

  9. Total uncertainty of low velocity thermal anemometers for measurement of indoor air movements

    DEFF Research Database (Denmark)

    Jørgensen, F.; Popiolek, Z.; Melikov, Arsen Krikor

    2004-01-01

    For a specific thermal anemometer with omnidirectional velocity sensor the expanded total uncertainty in measured mean velocity Û(Vmean) and the expanded total uncertainty in measured turbulence intensity Û(Tu) due to different error sources are estimated. The values are based on a previously...... developed mathematical model of the anemometer in combination with a large database of representative room flows measured with a 3-D Laser Doppler anemometer (LDA). A direct comparison between measurements with a thermal anemometer and a 3-D LDA in flows of varying velocity and turbulence intensity shows...... good agreement not only between the two instruments but also between the thermal anemometer and its mathematical model. The differences in the measurements performed with the two instruments are all well within the measurement uncertainty of both anemometers....

  10. The Measurement of cloud velocity using the pulsed laser and image tracking technique

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Seong-Ouk; Baik, Seung-Hoon; Park, Seung-Kyu; Park, Nak-Gyu; Kim, Dong-lyul; Ahn, Yong-Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The height of the clouds is also important for the three dimensional radiative interaction of aerosols and clouds, since the radiative effects vary strongly depending whether the cloud is above, below or even embedded in an aerosol layer. Clouds play an important role in climate change, in the prediction of local weather, and also in aviation safety when instrument assisted flying is unavailable. Presently, various ground-based instruments used for the measurements of the cloud base height or velocity. Lidar techniques are powerful and have many applications in climate studies, including the clouds' temperature measurement, the aerosol particle properties, etc. Otherwise, it is very circumscribed in cloud velocity measurements In this paper, we propose a new method to measure the cloud velocity. In this paper, we presented a method for the measurement of the cloud altitude and velocity using lidar's range detection and the tracking system. For the lidar system, we used an injection-seeded pulsed Nd:YAG laser as the transmitter to measure the distance to the target clouds. We used the DIC system to track the cloud image and calculate the actual displacement per unit time. The configured lidar system acquired the lidar signal of clouds at a distance of about 4 km. The developed fast correlation algorithm of the tracking, which is used to track the fast moving cloud relatively, was efficient for measuring the cloud velocity in real time. The measurement values had a linear distribution.

  11. Precision measurement of the speed of sound and thermodynamic properties of gases

    International Nuclear Information System (INIS)

    Benedetto, G.; Gavioso, R.M.; Spagnolo, R.

    1999-01-01

    The speed of sound in pure fluids and mixtures is a characteristic and important physical propriety which depends of several intensive thermodynamic variables. This fact indicates that it can be calculated using the appropriate thermodynamic properties of the fluid. Alternatively, experimental evaluation of the speed of sound can be used to determine several fundamental thermophysical properties. Recently, very accurate measurements of the speed of sound in dilute gases have found relevant applications: 1) the last experimental determinations of the value of the universal gas constant R, by measurements in argon, at the triple point of water (1,2); 2) revision of the thermodynamic temperature scales in different temperature ranges (3-5); 3) derivation of the state of many pure gases, which includes methane, helium and ethylene (6-7); 4)determination of the heat capacities and densities of pure gases and mixture (8-16). The aim of this paper is to provide an extensive review of the measurement of the speed of sound in gases and of its theoretical basis, giving prominence to the relevant metrological aspects involved in the determination of this physical quantity

  12. A dual-phantom system for validation of velocity measurements in stenosis models under steady flow.

    Science.gov (United States)

    Blake, James R; Easson, William J; Hoskins, Peter R

    2009-09-01

    A dual-phantom system is developed for validation of velocity measurements in stenosis models. Pairs of phantoms with identical geometry and flow conditions are manufactured, one for ultrasound and one for particle image velocimetry (PIV). The PIV model is made from silicone rubber, and a new PIV fluid is made that matches the refractive index of 1.41 of silicone. Dynamic scaling was performed to correct for the increased viscosity of the PIV fluid compared with that of the ultrasound blood mimic. The degree of stenosis in the models pairs agreed to less than 1%. The velocities in the laminar flow region up to the peak velocity location agreed to within 15%, and the difference could be explained by errors in ultrasound velocity estimation. At low flow rates and in mild stenoses, good agreement was observed in the distal flow fields, excepting the maximum velocities. At high flow rates, there was considerable difference in velocities in the poststenosis flow field (maximum centreline differences of 30%), which would seem to represent real differences in hydrodynamic behavior between the two models. Sources of error included: variation of viscosity because of temperature (random error, which could account for differences of up to 7%); ultrasound velocity estimation errors (systematic errors); and geometry effects in each model, particularly because of imperfect connectors and corners (systematic errors, potentially affecting the inlet length and flow stability). The current system is best placed to investigate measurement errors in the laminar flow region rather than the poststenosis turbulent flow region.

  13. Measuring snow water equivalent from common-offset GPR records through migration velocity analysis

    Science.gov (United States)

    St. Clair, James; Holbrook, W. Steven

    2017-12-01

    Many mountainous regions depend on seasonal snowfall for their water resources. Current methods of predicting the availability of water resources rely on long-term relationships between stream discharge and snowpack monitoring at isolated locations, which are less reliable during abnormal snow years. Ground-penetrating radar (GPR) has been shown to be an effective tool for measuring snow water equivalent (SWE) because of the close relationship between snow density and radar velocity. However, the standard methods of measuring radar velocity can be time-consuming. Here we apply a migration focusing method originally developed for extracting velocity information from diffracted energy observed in zero-offset seismic sections to the problem of estimating radar velocities in seasonal snow from common-offset GPR data. Diffractions are isolated by plane-wave-destruction (PWD) filtering and the optimal migration velocity is chosen based on the varimax norm of the migrated image. We then use the radar velocity to estimate snow density, depth, and SWE. The GPR-derived SWE estimates are within 6 % of manual SWE measurements when the GPR antenna is coupled to the snow surface and 3-21 % of the manual measurements when the antenna is mounted on the front of a snowmobile ˜ 0.5 m above the snow surface.

  14. Measuring snow water equivalent from common-offset GPR records through migration velocity analysis

    Directory of Open Access Journals (Sweden)

    J. St. Clair

    2017-12-01

    Full Text Available Many mountainous regions depend on seasonal snowfall for their water resources. Current methods of predicting the availability of water resources rely on long-term relationships between stream discharge and snowpack monitoring at isolated locations, which are less reliable during abnormal snow years. Ground-penetrating radar (GPR has been shown to be an effective tool for measuring snow water equivalent (SWE because of the close relationship between snow density and radar velocity. However, the standard methods of measuring radar velocity can be time-consuming. Here we apply a migration focusing method originally developed for extracting velocity information from diffracted energy observed in zero-offset seismic sections to the problem of estimating radar velocities in seasonal snow from common-offset GPR data. Diffractions are isolated by plane-wave-destruction (PWD filtering and the optimal migration velocity is chosen based on the varimax norm of the migrated image. We then use the radar velocity to estimate snow density, depth, and SWE. The GPR-derived SWE estimates are within 6 % of manual SWE measurements when the GPR antenna is coupled to the snow surface and 3–21 % of the manual measurements when the antenna is mounted on the front of a snowmobile  ∼  0.5 m above the snow surface.

  15. Blood flow velocity measurements in chicken embryo vascular network via PIV approach

    Science.gov (United States)

    Kurochkin, Maxim A.; Stiukhina, Elena S.; Fedosov, Ivan V.; Tuchin, Valery V.

    2018-04-01

    A method for measuring of blood velocity in the native vasculature of a chick embryo by the method of micro anemometry from particle images (μPIV) is improved. A method for interrogation regions sorting by the mask of the vasculature is proposed. A method for sorting of the velocity field of capillary blood flow is implemented. The in vitro method was evaluated for accuracy in a glass phantom of a blood vessel with a diameter of 50 μm and in vivo on the bloodstream of a chicken embryo, by comparing the transverse profile of the blood velocity obtained by the PIV method with the theoretical Poiseuille laminar flow profile.

  16. Measurements of Terminal Velocities of Cirrus Clouds in the Upper Trosphere

    Directory of Open Access Journals (Sweden)

    Nee Jan Bai

    2016-01-01

    Full Text Available Cirrus clouds are composed of ice crystals condensed from humidity due to low temperature condition in the upper atmosphere. The microphysics of cirrus clouds including sizes and shapes of ice particles are not well understood but are important in climate modeling. Ice crystal will fall under gravitational sedimentation to reach terminal velocities which depend on the size, mass, and ice habit. We studied here the terminal velocity of cirrus clouds by using lidar observations at Chungli (25N, 121E. The terminal velocities for a few cases of stable cirrus clouds are measured to determine the ice particle sizes and processes in the upper atmosphere.

  17. Measurement of velocity deficit at the downstream of a 1:10 axial hydrokinetic turbine model

    Energy Technology Data Exchange (ETDEWEB)

    Gunawan, Budi [ORNL; Neary, Vincent S [ORNL; Hill, Craig [St. Anthony Falls Laboratory, 2 Third Avenue SE, Minneapolis, MN 55414; Chamorro, Leonardo [St. Anthony Falls Laboratory, 2 Third Avenue SE, Minneapolis, MN 55414

    2012-01-01

    Wake recovery constrains the downstream spacing and density of turbines that can be deployed in turbine farms and limits the amount of energy that can be produced at a hydrokinetic energy site. This study investigates the wake recovery at the downstream of a 1:10 axial flow turbine model using a pulse-to-pulse coherent Acoustic Doppler Profiler (ADP). In addition, turbine inflow and outflow velocities were measured for calculating the thrust on the turbine. The result shows that the depth-averaged longitudinal velocity recovers to 97% of the inflow velocity at 35 turbine diameter (D) downstream of the turbine.

  18. Molecular Rayleigh Scattering Diagnostic for Dynamic Temperature, Velocity, and Density Measurements

    Science.gov (United States)

    Mielke, Amy R.; Elam, Kristie A.; Sung, Chi-Jen

    2006-01-01

    A molecular Rayleigh scattering technique is developed to measure dynamic gas temperature, velocity, and density in unseeded turbulent flows at sampling rates up to 16 kHz. A high power CW laser beam is focused at a point in an air jet plume and Rayleigh scattered light is collected and spectrally resolved. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. The circular interference fringe pattern is divided into four concentric regions and sampled at 1 and 16 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows for measurement of gas temperature and velocity. Independently monitoring the total scattered light intensity provides a measure of gas density. A low speed heated jet is used to validate the measurement of temperature fluctuations and an acoustically excited nozzle flow is studied to validate velocity fluctuation measurements. Power spectral density calculations of the property fluctuations, as well as mean and fluctuating quantities are presented. Temperature fluctuation results are compared with constant current anemometry measurements and velocity fluctuation results are compared with constant temperature anemometry measurements at the same locations.

  19. An experiment to measure the one-way velocity of propagation of electromagnetic radiation

    Science.gov (United States)

    Kolen, P.; Torr, D. G.

    1982-01-01

    An experiment involving commercially available instrumentation to measure the velocity of the earth with respect to absolute space is described. The experiment involves the measurement of the one-way propagation velocity of electromagnetic radiation down a high-quality coaxial cable. It is demonstrated that the experiment is both physically meaningful and exceedingly simple in concept and in implementation. It is shown that with currently available commercial equipment one might expect to detect a threshold value for the component of velocity of the earth's motion with respect to absolute space in the equatorial plane of approximately 10 km/s, which greatly exceeds the velocity resolution required to detect the motion of the solar system with respect to the center of the galaxy.

  20. Parallel ion flow velocity measurement using laser induced fluorescence method in an electron cyclotron resonance plasma

    International Nuclear Information System (INIS)

    Yoshimura, Shinji; Okamoto, Atsushi; Terasaka, Kenichiro; Ogiwara, Kohei; Tanaka, Masayoshi Y.; Aramaki, Mitsutoshi

    2010-01-01

    Parallel ion flow velocity along a magnetic field has been measured using a laser induced fluorescence (LIF) method in an electron cyclotron resonance (ECR) argon plasma with a weakly-diverging magnetic field. To measure parallel flow velocity in a cylindrical plasma using the LIF method, the laser beam should be injected along device axis; however, the reflection of the incident beam causes interference between the LIF emission of the incident and reflected beams. Here we present a method of quasi-parallel laser injection at a small angle, which utilizes the reflected beam as well as the incident beam to obtain the parallel ion flow velocity. Using this method, we observed an increase in parallel ion flow velocity along the magnetic field. The acceleration mechanism is briefly discussed on the basis of the ion fluid model. (author)

  1. 3D velocity measurements in fluid flows using multiple exposure holography

    International Nuclear Information System (INIS)

    Stanislas, M.; Rodriguez, O.; Dadi, M.; Beluche, F.

    1987-01-01

    An account is given of multiple exposure holography's application to the measurement of velocity in fluid flows. The method is nonintrusive, and yields access to the three components of the instantaneous velocity in three-dimensional domains. These characteristics render such holographic data complementary to classical LDV. Attention is given to solutions proposed for such limitations inherent in the method as the rather lengthy acquisition time; this difficulty is presently addressed by means of an automated evaluation methodology. 12 references

  2. Measuring the Angular Velocity of a Propeller with Video Camera Using Electronic Rolling Shutter

    Directory of Open Access Journals (Sweden)

    Yipeng Zhao

    2018-01-01

    Full Text Available Noncontact measurement for rotational motion has advantages over the traditional method which measures rotational motion by means of installing some devices on the object, such as a rotary encoder. Cameras can be employed as remote monitoring or inspecting sensors to measure the angular velocity of a propeller because of their commonplace availability, simplicity, and potentially low cost. A defect of the measurement with cameras is to process the massive data generated by cameras. In order to reduce the collected data from the camera, a camera using ERS (electronic rolling shutter is applied to measure angular velocities which are higher than the speed of the camera. The effect of rolling shutter can induce geometric distortion in the image, when the propeller rotates during capturing an image. In order to reveal the relationship between the angular velocity and the image distortion, a rotation model has been established. The proposed method was applied to measure the angular velocities of the two-blade propeller and the multiblade propeller. The experimental results showed that this method could detect the angular velocities which were higher than the camera speed, and the accuracy was acceptable.

  3. Characterization of the alumina-zirconia ceramic system by ultrasonic velocity measurements

    International Nuclear Information System (INIS)

    Carreon, Hector; Ruiz, Alberto; Medina, Ariosto; Barrera, Gerardo; Zarate, Juan

    2009-01-01

    In this work an alumina-zirconia ceramic composites have been prepared with α-Al 2 O 3 contents from 10 to 95 wt.%. The alumina-zirconia ceramic system was characterized by means of precise ultrasonic velocity measurements. In order to find out the factors affecting the variation in wave velocity, the ceramic composite have been examined by X-ray diffraction (XRD) and (SEM) scanning electron microscopy. It was found that the ultrasonic velocity measurements changed considerably with respect to the ceramic composite composition. In particular, we studied the behavior of the physical material property hardness, an important parameter of the ceramic composite mechanical properties, with respect to the variation in the longitudinal and shear wave velocities. Shear wave velocities exhibited a stronger interaction with microstructural and sub-structural features as compared to that of longitudinal waves. In particular, this phenomena was observed for the highest α-Al 2 O 3 content composite. Interestingly, an excellent correlation between ultrasonic velocity measurements and ceramic composite hardness was observed.

  4. Video imaging measurement of interfacial wave velocity in air-water flow through a horizontal elbow

    Science.gov (United States)

    Al-Wazzan, Amir; Than, Cheok F.; Moghavvemi, Mahmoud; Yew, Chia W.

    2001-10-01

    Two-phase flow in pipelines containing elbows represents a common situation in the oil and gas industries. This study deals with the stratified flow regime between the gas and liquid phase through an elbow. It is of interest to study the change in wave characteristics by measuring the wave velocity and wavelength at the inlet and outlet of the elbow. The experiments were performed under concurrent air-water stratified flow in a horizontal transparent polycarbonate pipe of 0.05m diameter and superficial air and water velocities up to 8.97 and 0.0778 m/s respectively. A non-intrusive video imaging technique was applied to capture the waves. For image analysis, a frame by frame direct overlapping method was used to detect for pulsating flow and a pixel shifting method based on the detection of minimum values in the overlap function was used to determine wave velocity and wavelength. Under superficial gas velocity of less than 4.44 m/s, the results suggest a regular pulsating outflow produced by the elbow. At higher gas velocities, more random pulsation was found and the emergence of localized interfacial waves was detected. Wave velocities measured by this technique were found to produce satisfactory agreement with direct measurements.

  5. NIS method for uncertainty estimation of airborne sound insulation measurement in field

    Directory of Open Access Journals (Sweden)

    El-Basheer Tarek M.

    2017-01-01

    Full Text Available In structures, airborne sound insulation is utilized to characterize the acoustic nature of barriers between rooms. However, the assessment of sound insulation index is once in a while troublesome or indeed, even questionable, both in field and laboratory measurements, notwithstanding the way that there are some unified measurement methodology indicated in the ISO 140 series standards. There are issues with the reproducibility and repeatability of the measurement results. A few troubles might be brought on by non-diffuse acoustic fields, non-uniform reverberation time, or blunders of the reverberation time measurements. Some minor issues are additionally postured by flanking transmission. In this paper, investigation of the uncertainties of the above specified measurement parts and their impact on the consolidated uncertainty in 1/3-octave frequency band. The total measurement uncertainty model contributes several different partial uncertainties, which are evaluated by the method of type A or type B. Also, the determination of the sound reduction index decided by ISO 140-4 has been performed.

  6. Measurement of the sound power incident on the walls of a reverberation room with near field acoustic holography

    DEFF Research Database (Denmark)

    Jacobsen, Finn; Tiana Roig, Elisabet

    2010-01-01

    area; and it has always been regarded as impossible to measure the sound power that is incident on a wall directly. This paper examines a new method of determining this quantity from sound pressure measurements at positions on the wall using 'statistically optimised near field acoustic holography...

  7. Nearly simultaneous measurements of radar auroral heights and Doppler velocities at 398 MHz

    International Nuclear Information System (INIS)

    Moorcroft, D.; Ruohoniemi, J.M.

    1987-01-01

    Nearly simultaneous measurements of radar auroral heights and Doppler velocities were obtained using the Homer, Alaska, 398-MHz phased-array radar over a total of 16 hours on four different days. The heights show a consistent variation with time, being highest near the time of electrojet current reversal, and lowest late in the morning. A variety of east-west height asymmetries were observed, different from those previously reported, which can be explained in terms of favorable flow angles preferentially favoring high-altitude primary two-stream waves to one side of the field of view. Low-velocity echoes, presumably due to secondary irregularities, are found to be more restricted in height range than echoes with ion acoustic velocities, which presumably come from primary two-stream instabilities. Echo power was examined as a function of velocity and height. For the westward electrojet it was found that echoes with ion acoustic velocities are relatively constant in strength over most of their height range, but for low-velocity echoes the power is a maximum between 100 and 105 km and falls off steadily at greater heights. Doppler speeds show a noticeable decrease at heights below 105 km, in agreement with the expected variation in ion acoustic velocity

  8. Volumetric velocity measurements in restricted geometries using spiral sampling: a phantom study.

    Science.gov (United States)

    Nilsson, Anders; Revstedt, Johan; Heiberg, Einar; Ståhlberg, Freddy; Bloch, Karin Markenroth

    2015-04-01

    The aim of this study was to evaluate the accuracy of maximum velocity measurements using volumetric phase-contrast imaging with spiral readouts in a stenotic flow phantom. In a phantom model, maximum velocity, flow, pressure gradient, and streamline visualizations were evaluated using volumetric phase-contrast magnetic resonance imaging (MRI) with velocity encoding in one (extending on current clinical practice) and three directions (for characterization of the flow field) using spiral readouts. Results of maximum velocity and pressure drop were compared to computational fluid dynamics (CFD) simulations, as well as corresponding low-echo-time (TE) Cartesian data. Flow was compared to 2D through-plane phase contrast (PC) upstream from the restriction. Results obtained with 3D through-plane PC as well as 4D PC at shortest TE using a spiral readout showed excellent agreements with the maximum velocity values obtained with CFD (spiral sequences were respectively 14 and 13 % overestimated compared to CFD. Identification of the maximum velocity location, as well as the accurate velocity quantification can be obtained in stenotic regions using short-TE spiral volumetric PC imaging.

  9. Particle image velocimetry measurements of 2-dimensional velocity field around twisted tape

    Energy Technology Data Exchange (ETDEWEB)

    Song, Min Seop; Park, So Hyun; Kim, Eung Soo, E-mail: kes7741@snu.ac.kr

    2016-11-01

    Highlights: • Measurements of the flow field in a pipe with twisted tape were conducted by particle image velocimetry (PIV). • A novel matching index of refraction technique utilizing 3D printing and oil mixture was adopted to make the test section transparent. • Undistorted particle images were clearly captured in the presence of twisted tape. • 2D flow field in the pipe with twisted tape revealed the characteristic two-peak velocity profile. - Abstract: Twisted tape is a passive component used to enhance heat exchange in various devices. It induces swirl flow that increases the mixing of fluid. Thus, ITER selected the twisted tape as one of the candidates for turbulence promoting in the divertor cooling. Previous study was mainly focused on the thermohydraulic performance of the twisted tape. As detailed data on the velocity field around the twisted tape was insufficient, flow visualization study was performed to provide fundamental data on velocity field. To visualize the flow in a complex structure, novel matching index of refraction technique was used with 3-D printing and mixture of anise and mineral oil. This technique enables the camera to capture undistorted particle image for velocity field measurement. Velocity fields at Reynolds number 1370–9591 for 3 different measurement plane were obtained through particle image velocimetry. The 2-dimensional averaged velocity field data were obtained from 177 pair of instantaneous velocity fields. It reveals the characteristic two-peak flow motion in axial direction. In addition, the normalized velocity profiles were converged with increase of Reynolds numbers. Finally, the uncertainty of the result data was analyzed.

  10. Ultrasonic velocity measurements- a potential sensor for intelligent processing of austenitic stainless steels

    International Nuclear Information System (INIS)

    Venkadesan, S.; Palanichamy, P.; Vasudevan, M.; Baldev Raj

    1996-01-01

    Development of sensors based on Non-Destructive Evaluation (NDE) techniques for on-line sensing of microstructure and properties requires a thorough knowledge on the relation between the sensing mechanism/measurement of an NDE technique and the microstructure. As a first step towards developing an on-line sensor for studying the dynamic microstructural changes during processing of austenitic stainless steels, ultrasonic velocity measurements have been carried out to study the microstructural changes after processing. Velocity measurements could follow the progress of annealing starting from recovery, onset and completion of recrystallization, sense the differences in the microstructure obtained after hot deformation and estimate the grain size. This paper brings out the relation between the sensing method based on ultrasonic velocity measurements and the microstructure in austenitic stainless steel. (author)

  11. Liner velocity, current, and symmetry measurements on the 32 MA flux compression generator experiment ALT-1

    CERN Document Server

    Clark, D A; Rodríguez, G; Tabaka, L J

    2001-01-01

    Summary form only given, as follows. A flux compression generator based pulse power system, designed, built, and fielded by a Russian team at the All Russian Scientific Research Institute of Experimental Physics (VNIIEF), was used to successfully drive an aluminum liner to velocities greater than 10 km/sec. The experiment objective was to demonstrate performance of a precision liner implosion at Atlas current of 30 MA or greater. Diagnostics to measure liner performance were an essential part of the experiment. An experimental team from Los Alamos National Laboratory (LANL) provided a suite of diagnostics to measure liner performance. Three diagnostics were fielded. 1. a velocity interferometer (VISAR) to continuously measure the liner inner surface velocity from throughout the entire range of travel. 2. Two Faraday rotation devices to measure liner current during the implosion. 3. Sixteen fiber optic impact pins to record liner impact time and provide axial and azimuthal symmetry information. All diagnostics...

  12. A Measure Based on Beamforming Power for Evaluation of Sound Field Reproduction Performance

    Directory of Open Access Journals (Sweden)

    Ji-Ho Chang

    2017-03-01

    Full Text Available This paper proposes a measure to evaluate sound field reproduction systems with an array of loudspeakers. The spatially-averaged squared error of the sound pressure between the desired and the reproduced field, namely the spatial error, has been widely used, which has considerable problems in two conditions. First, in non-anechoic conditions, room reflections substantially deteriorate the spatial error, although these room reflections affect human localization to a lesser degree. Second, for 2.5-dimensional reproduction of spherical waves, the spatial error increases consistently due to the difference in the amplitude decay rate, whereas the degradation of human localization performance is limited. The measure proposed in this study is based on the beamforming powers of the desired and the reproduced fields. Simulation and experimental results show that the proposed measure is less sensitive to room reflections and the amplitude decay than the spatial error, which is likely to agree better with the human perception of source localization.

  13. A Measure Based on Beamforming Power for Evaluation of Sound Field Reproduction Performance

    DEFF Research Database (Denmark)

    Chang, Ji-ho; Jeong, Cheol-Ho

    2017-01-01

    This paper proposes a measure to evaluate sound field reproduction systems with an array of loudspeakers. The spatially-averaged squared error of the sound pressure between the desired and the reproduced field, namely the spatial error, has been widely used, which has considerable problems in two...... conditions. First, in non-anechoic conditions, room reflections substantially deteriorate the spatial error, although these room reflections affect human localization to a lesser degree. Second, for 2.5-dimensional reproduction of spherical waves, the spatial error increases consistently due...... to the difference in the amplitude decay rate, whereas the degradation of human localization performance is limited. The measure proposed in this study is based on the beamforming powers of the desired and the reproduced fields. Simulation and experimental results show that the proposed measure is less sensitive...

  14. Determination of the filtration velocities and mean velocity in ground waters using radiotracers

    International Nuclear Information System (INIS)

    Duran P, Oscar; Diaz V, Francisco; Heresi M, Nelida

    1994-01-01

    An experimental method to determine filtration, or, Darcy velocity and mean velocity in underground waters using radiotracers, is described. After selecting the most appropriate tracers, from 6 chemical compounds, to measure water velocity, a method to measure filtration velocity was developed. By fully labelling the water column with 2 radioisotopes, Br and tritium, almost identical values were obtained for the aquifer filtration velocity in the sounding S1. This value was 0.04 m/d. Field porosity was calculated at 11% and mean velocity at 0.37 m.d. With the filtration velocity value and knowing the hydraulic variation between the soundings S1 and S2 placed at 10 meters, field permeability was estimated at 2.4 x 10 m/s. (author)

  15. A first comparison of irregularity and ion drift velocity measurements in the E-region

    Directory of Open Access Journals (Sweden)

    R. A. Makarevich

    2006-09-01

    Full Text Available E-region irregularity velocity measurements at large flow angles with the STARE Finland coherent VHF radar are considered in context of the ion and electron velocity data provided by the EISCAT tristatic radar system, CUTLASS Finland coherent HF radar, and IMAGE fluxgate magnetometers. The data have been collected during a special experiment on 27 March 2004 during which EISCAT was scanning between several E- and one F-region altitudes along the magnetic field line. Within the E-region, the EISCAT measurements at two altitudes of 110 and 115 km are considered while the electron velocity is inferred from the EISCAT ion velocity measurements at 278 km. The line-of-sight (l-o-s VHF velocity measured by STARE VHF los is compared to the ion and electron velocity components (Vi0 comp and Ve0 comp along the STARE l-o-s direction. The comparison with Ve0 comp for the entire event shows that the measurements exhibit large scatter and small positive correlation. The correlation with Ve0 comp was substantial in the first half of the interval under study when Ve0 comp was larger in magnitude. The comparison with Vi0 comp at 110 and 115 km shows a considerable positive correlation, with VHF velocity being typically larger (smaller in magnitude than Vi0 comp at 110 km (115 km so that VVHF los appears to be bounded by the ion velocity components at two altitudes. It is also demonstrated that the difference between VVHF los and Vi0 comp at 110 km can be treated, in the first approximation, as a linear function of the effective backscatter height heff also counted from 110 km; heff varies in the range 108–114 km due to the altitude integration effects in the scattering cross-section. Our results are consistent with the notion that VHF

  16. Simultaneous measurement of particle and fluid velocities in particle-laden flows

    International Nuclear Information System (INIS)

    Jin, D. X.; Lee, D. Y.

    2009-01-01

    For the velocity measurement in a particle-laden fluid flow, the fluid velocity and the inherently dispersed particle velocity can be analyzed by using PIV and PTV, respectively. Since the PIV result statistically represents the average displacement of all the particles in a PIV image, it is inevitable that the PIV result includes the influence of the dispersed particles' displacement if a single CCD camera is used to simultaneously measure the fluid velocity and the dispersed particle velocity. The influence of dispersed particles should be excluded before the PIV analysis in order to evaluate the fluid velocity accurately. In this study, the optimum replacement brightness of dispersed particles to minimize the false influence of dispersed particles on the PIV analysis was theoretically derived. Simulation results show that the modification of dispersed particle brightness can significantly reduce the PIV error caused by the dispersed particles. This modification method was also verified in the analysis of an actual experimental case of the particle-laden fluid flow in a triangular grooved channel

  17. High resolution measurement of the velocity profiles of channel flows using the particle image velocimetry technique

    International Nuclear Information System (INIS)

    Nor Azizi Mohamed

    2000-01-01

    The high resolution velocity profiles of a uniform steady channel flow and a flow beneath waves were obtained using the particle image velocimetry (PIV) technique. The velocity profiles for each flow were calculated for both components. It is shown that the profiles obtained are very precise, displaying the point velocities from a few millimeters from the bottom of the channel up to the water surface across the water depth. In the case of the wave-induced flow, the profiles are shown under the respective wave phases and given in a plane representation. High resolution measurement of point velocities in a flow is achievable using PIV and invaluable when applied to a complex flow. (Author)

  18. Determination of the Ion Velocity Distribution in a Rotating Plasma from Measurements of Doppler Broadening

    DEFF Research Database (Denmark)

    Jørgensen, L. W.; Sillesen, Alfred Hegaard

    1979-01-01

    The Doppler-broadened profile of the He II 4685.75 AA line was measured along a chord in a rotating plasma, transverse to the magnetic field. Using a single-particle orbit picture, the corresponding velocity spectrum of ions confirm the measurements, so it can be concluded that the single-particl...

  19. Measurement for the MLC leaf velocity profile by considering the leaf leakage using a radiographic film

    International Nuclear Information System (INIS)

    Chow, James C L; Grigorov, Grigor N

    2006-01-01

    A method to measure the velocity profile of a multi-leaf collimator (MLC) leaf along its travel range using a radiographic film is reported by considering the intra-leaf leakage. A specific dynamic MLC field with leaves travelling from the field edge to the isocentre line was designed. The field was used to expose a radiographic film, which was then scanned, and the dose profile along the horizontal leaf axis was measured. The velocity at a sampling point on the film can be calculated by considering the horizontal distance between the sampling point and the isocentre line, dose at the sampling point, dose rate of the linear accelerator, the total leaf travel time from the field edge to isocentre line and the pre-measured dose rate of leaf leakage. With the leaf velocities and velocity profiles for all MLC leaves measured routinely, a comprehensive and simple QA for the MLC can be set up to test the consistency of the leaf velocity performance which is essential to the IMRT delivery using a sliding window technique. (note)

  20. Pulmonary branch arterial flow can be measured with cine MR velocity mapping

    International Nuclear Information System (INIS)

    Caputo, G.R.; Kondo, C.; Masui, T.; Foster, E.; Geraci, S.J.; O'Sullivan, M.; Higgins, C.B.

    1990-01-01

    This paper assesses the capability of cine MR phase velocity mapping (CVM) to measure main, right-sided, and left-sided pulmonary arterial (PA) blood flow. The authors examined a constant-flow phantom and nine healthy volunteers with use of 1.5-T MR imaging system (GE Signa) with phase velocity cine sequences. CVM correctly measured constant-flow phantom velocities (range, 20-190 cm/sec; r = .998, SEE = 4.2 cm/sec), and velocity with use of angulated planes to section the phantom tube perpendicularly. CVM peak systolic main PA velocity (79 cm/sec ± 10) correlated well with Doppler US measurements (80 cm/sec ± 7). CVM main PA flow correlated well with conventional cine MR LV stroke volume measurements (r = .98, SEE = 4.8 mL). Left and right PA flow on the angulated planes were 29 mL ± 7 and 34 mL ± 10, respectively

  1. Helioseismic measurements in the solar envelope using group velocities of surface waves

    Science.gov (United States)

    Vorontsov, S. V.; Baturin, V. A.; Ayukov, S. V.; Gryaznov, V. K.

    2014-07-01

    At intermediate- and high-degree l, solar p and f modes can be considered as surface waves. Using variational principle, we derive an integral expression for the group velocities of the surface waves in terms of adiabatic eigenfunctions of normal modes, and address the benefits of using group-velocity measurements as a supplementary diagnostic tool in solar seismology. The principal advantage of using group velocities, when compared with direct analysis of the oscillation frequencies, comes from their smaller sensitivity to the uncertainties in the near-photospheric layers. We address some numerical examples where group velocities are used to reveal inconsistencies between the solar models and the seismic data. Further, we implement the group-velocity measurements to the calibration of the specific entropy, helium abundance Y, and heavy-element abundance Z in the adiabatically stratified part of the solar convective envelope, using different recent versions of the equation of state. The results are in close agreement with our earlier measurements based on more sophisticated analysis of the solar oscillation frequencies. These results bring further support to the downward revision of the solar heavy-element abundances in recent spectroscopic measurements.

  2. On-line velocity measurements using phase probes at the SuperHILAC

    International Nuclear Information System (INIS)

    Feinberg, B.; Meaney, D.; Thatcher, R.; Timossi, C.

    1987-12-01

    Phase probes have been placed in several external beam lines at the LBL heavy ion linear accelerator (SuperHILAC) to provide non- destructive velocity measurements independent of the ion being accelerated. The system uses three probes in each line to obtain accurate velocity measurements at all beam energies. Automatic gain control and signal analysis are performed so that the energy/nucleon along with up to three probe signals are displayed on a vector graphics display with a refresh rate better than twice per second. The system uses a sensitive pseudo-correlation technique to pick out the signal from the noise, features simultaneous measurements of up to four ion velocities when more than one beam is being accelerated, and is controlled by a touch-screen operator interface. It is accurate to within /+-/0.25% and has provisions for on-line calibration tests. The phase probes thus provide a velocity measurement independent of the mass defect associated with the use of crystal detectors, which can become significant for heavy elements. They are now used as a routine tuning aid to ensure proper bunch structure, and as a beam velocity monitor. 3 refs., 5 figs

  3. Development of Autonomous Boat-Type Robot for Automated Velocity Measurement in Straight Natural River

    Science.gov (United States)

    Sanjou, Michio; Nagasaka, Tsuyoshi

    2017-11-01

    The present study describes an automated system to measure the river flow velocity. A combination of the camera-tracking system and the Proportional/Integral/Derivative (PID) control could enable the boat-type robot to remain in position against the mainstream; this results in reasonable evaluation of the mean velocity by a duty ratio which corresponds to rotation speed of the screw propeller. A laser range finder module was installed to measure the local water depth. Reliable laboratory experiments with the prototype boat robot and electromagnetic velocimetry were conducted to obtain a calibration curve that connects the duty ratio and mean current velocity. The remaining accuracy in the target point was also examined quantitatively. The fluctuation in the spanwise direction is within half of the robot length. It was therefore found that the robot remains well within the target region. We used two-dimensional navigation tests to guarantee that the prototype moved smoothly to the target points and successfully measured the streamwise velocity profiles across the mainstream. Moreover, the present robot was found to move successfully not only in the laboratory flume but also in a small natural river. The robot could move smoothly from the starting point near the operator's site toward the target point where the velocity is measured, and it could evaluate the cross-sectional discharge.

  4. Measured anisotropic air flow resistivity and sound attenuation of glass wool

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    2002-01-01

    Department of Mechanical Engineering, Technical University of Denmark, Bygning 358, DK 2800 Lyngby, Denmark The air flow resistivity of glass wool has been measured in different directions. The glass wool was delivered from the manufacturer as slabs measuring 100×600×900 mm3, where the surface 600...... 7.75 kPa s m**2. A formula for prediction of resistivity for other densities is given. By comparing measured values of sound attenuation with results calculated from resistivity data, it is demonstrated that the measured attenuation can be predicted in a simple manner. ©2002 Acoustical Society...

  5. Measurement of transient two-phase flow velocity using statistical signal analysis of impedance probe signals

    International Nuclear Information System (INIS)

    Leavell, W.H.; Mullens, J.A.

    1981-01-01

    A computational algorithm has been developed to measure transient, phase-interface velocity in two-phase, steam-water systems. The algorithm will be used to measure the transient velocity of steam-water mixture during simulated PWR reflood experiments. By utilizing signals produced by two, spatially separated impedance probes immersed in a two-phase mixture, the algorithm computes the average transit time of mixture fluctuations moving between the two probes. This transit time is computed by first, measuring the phase shift between the two probe signals after transformation to the frequency domain and then computing the phase shift slope by a weighted least-squares fitting technique. Our algorithm, which has been tested with both simulated and real data, is able to accurately track velocity transients as fast as 4 m/s/s

  6. Velocity Field Measurements of Human Coughing Using Time Resolved Particle Image Velocimetry

    Science.gov (United States)

    Khan, T.; Marr, D. R.; Higuchi, H.; Glauser, M. N.

    2003-11-01

    Quantitative fluid mechanics analysis of human coughing has been carried out using new Time Resolved Particle Image Velocimetry (TRPIV). The study involves measurement of velocity vector time-histories and velocity profiles. It is focused on the average normal human coughing. Some work in the past on cough mechanics has involved measurement of flow rates, tidal volumes and sub-glottis pressure. However, data of unsteady velocity vector field of the exiting highly time-dependent jets is not available. In this study, human cough waveform data are first acquired in vivo using conventional respiratory instrumentation for various volunteers of different gender/age groups. The representative waveform is then reproduced with a coughing/breathing simulator (with or without a manikin) for TRPIV measurements and analysis. The results of this study would be useful not only for designing of indoor air quality and heating, ventilation and air conditioning systems, but also for devising means of protection against infectious diseases.

  7. Trajectory and velocity measurement of a particle in spray by digital holography

    Energy Technology Data Exchange (ETDEWEB)

    Lue Qieni; Chen Yiliang; Yuan Rui; Ge Baozhen; Gao Yan; Zhang Yimo

    2009-12-20

    We present a method for the trajectory and the velocity measurement of a particle in spray by digital holography. Based on multiple exposure digital in-line holography, a sequence of digital holograms of a dynamic spray particle field at different times are recorded with a CW laser and a high-speed CCD. The time evolution of the serial positions of particles, i.e., the motion trajectories of the particles, is obtained by numerically reconstructing the synthetic hologram of a sequence of digital holograms. The center coordinate (x,y) of each particle image can be extracted using a Hough transform and subpixel precision computing, and the velocity of an individual particle can also be obtained, which is then applied to measuring the velocity of diesel spray and alcohol spray. The research shows that the method presented in this paper for measuring spray field is feasible.

  8. Measurements of ammonia concentrations, fluxes and dry deposition velocities to a spruce forest 1991-1995

    DEFF Research Database (Denmark)

    Andersen, H.V.; Hovmand, M.F.; Hummelshøj, P.

    1999-01-01

    The dry deposition velocities and fluxes of ammonia have been estimated from measurements of the vertical gradient of ammonia and micrometeorology above a spruce forest in western Jutland, Denmark. Measurements have been made in seven periods, each lasting about one week and covering all seasons...... measuring period characterized by easterly winds with dry conditions and high ammonia concentrations, and the emissions might relate to evaporation from ammonia saturated surfaces or emission from mineralization in the forest soil. In general, relatively high net deposition velocities were observed during...... at conditions with easterly winds, the air have passed central Jutland with large emission areas. Some of the relatively low deposition velocities or emissions were observed during conditions with low ammonia concentration and westerly winds. These observations might relate to a compensation point of the forest...

  9. Simultaneous measurement of particle velocity and size based on gray difference and autocorrelation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The gray of two images of a same particle taken by a digital camera with different exposure times is different too. Based on the gray difference of particle images in a double-exposed photo and autocorrelation processing of digital images,this paper proposes a method for measuring particle velocities and sizes simultaneously. This paper also introduces the theoretical foundation of this method,the process of particle imaging and image processing,and the simultaneous measurement of velocity and size of a low speed flow field with 35 μm and 75 μm standard particles. The graphical measurement results can really reflect the flow characteristics of the flow field. In addition,although the measured velocity and size histograms of these two kinds of standard particles are slightly wider than the theoretical ones,they are all still similar to the normal distribution,and the peak velocities and diameters of the histograms are consistent with the default values. Therefore,this measurement method is capable of providing moderate measurement accuracy,and it can be further developed for high-speed flow field measurements.

  10. A Model for the prediction of Sound Levels within a Symphonic Orchestra based on measured Sound Strength

    NARCIS (Netherlands)

    Wenmaekers, R.H.C.; Hak, C.C.J.M.; Luxemburg, van L.C.J.

    2011-01-01

    Members and directors of symphonic orchestras are concerned about the noise levels musicians are exposed to and their ease of playing ensemble. The results of many research has shown that the noise levels within an orchestra can be high. Also, research has shown that the sound level will vary

  11. Dynamic PIV measurement on the effect of sound wave in upper plenum of boiling water reactor

    International Nuclear Information System (INIS)

    Kumagai, Kosuke; Someya, Satoshi; Okamoto, Koji

    2008-01-01

    In one of the power uprated plants in the United States, the steam dryer breakages due to fatigue fracture occurred. It is conceivable that the increased steam flow passing through the branches caused a self-induced vibration with the propagation of sound wave into the steam-dome. The resonance among the structure, flow and the pressure fluctuation resulted in the breakages. To understand the basic mechanism of the resonance, previous researches were done by a point measurement of the pressure and by a phase averaged measurement of the flow, while it was difficult to detect the interaction among them by the conventional method. In the preliminary study, Dynamic Particle Image Velocimetry (PIV) System was applied to investigate the effect of sound on the flow. (author)

  12. Estimated carotid-femoral pulse wave velocity has similar predictive value as measured carotid-femoral pulse wave velocity

    DEFF Research Database (Denmark)

    Greve, Sara V; Blicher, Marie K; Kruger, Ruan

    2016-01-01

    BACKGROUND: Carotid-femoral pulse wave velocity (cfPWV) adds significantly to traditional cardiovascular risk prediction, but is not widely available. Therefore, it would be helpful if cfPWV could be replaced by an estimated carotid-femoral pulse wave velocity (ePWV) using age and mean blood pres...... that these traditional risk scores have underestimated the complicated impact of age and blood pressure on arterial stiffness and cardiovascular risk....

  13. Immersed transient eddy current flow metering: a calibration-free velocity measurement technique for liquid metals

    Science.gov (United States)

    Krauter, N.; Stefani, F.

    2017-10-01

    Eddy current flow meters are widely used for measuring the flow velocity of electrically conducting fluids. Since the flow induced perturbations of a magnetic field depend both on the geometry and the conductivity of the fluid, extensive calibration is needed to get accurate results. Transient eddy current flow metering has been developed to overcome this problem. It relies on tracking the position of an impressed eddy current system that is moving with the same velocity as the conductive fluid. We present an immersed version of this measurement technique and demonstrate its viability by numerical simulations and a first experimental validation.

  14. Retinal hemodynamic oxygen reactivity assessed by perfusion velocity, blood oximetry and vessel diameter measurements

    DEFF Research Database (Denmark)

    Klefter, Oliver Niels; Lauritsen, Anne Øberg; Larsen, Michael

    2015-01-01

    PURPOSE: To test the oxygen reactivity of a fundus photographic method of measuring macular perfusion velocity and to integrate macular perfusion velocities with measurements of retinal vessel diameters and blood oxygen saturation. METHODS: Sixteen eyes in 16 healthy volunteers were studied at two...... is a valid method for assessing macular perfusion. Results were consistent with previous observations of hyperoxic blood flow reduction using blue field entoptic and laser Doppler velocimetry. Retinal perfusion seemed to be regulated around individual set points according to blood glucose levels. Multimodal...

  15. Immersed transient eddy current flow metering: a calibration-free velocity measurement technique for liquid metals

    International Nuclear Information System (INIS)

    Krauter, N; Stefani, F

    2017-01-01

    Eddy current flow meters are widely used for measuring the flow velocity of electrically conducting fluids. Since the flow induced perturbations of a magnetic field depend both on the geometry and the conductivity of the fluid, extensive calibration is needed to get accurate results. Transient eddy current flow metering has been developed to overcome this problem. It relies on tracking the position of an impressed eddy current system that is moving with the same velocity as the conductive fluid. We present an immersed version of this measurement technique and demonstrate its viability by numerical simulations and a first experimental validation. (paper)

  16. Validity and reliability of simple measurement device to assess the velocity of the barbell during squats.

    Science.gov (United States)

    Lorenzetti, Silvio; Lamparter, Thomas; Lüthy, Fabian

    2017-12-06

    The velocity of a barbell can provide important insights on the performance of athletes during strength training. The aim of this work was to assess the validity and reliably of four simple measurement devices that were compared to 3D motion capture measurements during squatting. Nine participants were assessed when performing 2 × 5 traditional squats with a weight of 70% of the 1 repetition maximum and ballistic squats with a weight of 25 kg. Simultaneously, data was recorded from three linear position transducers (T-FORCE, Tendo Power and GymAware), an accelerometer based system (Myotest) and a 3D motion capture system (Vicon) as the Gold Standard. Correlations between the simple measurement devices and 3D motion capture of the mean and the maximal velocity of the barbell, as well as the time to maximal velocity, were calculated. The correlations during traditional squats were significant and very high (r = 0.932, 0.990, p squats and was less accurate. All the linear position transducers were able to assess squat performance, particularly during traditional squats and especially in terms of mean velocity and time to maximal velocity.

  17. On the Measurement of the Velocity of Light Emitted by an Ultrarelativistic Source

    Science.gov (United States)

    Kupryaev, N. V.

    2015-01-01

    By analytical calculations it has been shown that in papers on the measurement of the velocity of light published in 2011 in the journals Uspekhi Fizicheskikh Nauk [Physics-Uspekhi] and Pis'ma v ZhETF [JRTP Letters], in actual fact the velocity of a light pulse from a relativistic clot of electrons was not measured. All that was done was to compare the velocity of light emitted by an ultrarelativistic source with the velocity of light from a fixed source, i.e., both in the first and second variants (one independent quantity was compared with another), in essence, it was simply postulated. In the first variant a glass plate was used as the fixed light source, and in the second variants, a synchrotron pulse was used as the reference signal. The velocity of light was calculated using a calculated time based on the postulate of the special theory of relativity (STR) on the invariance of the velocity of light. This, of course, contradicts the Newton-Ritz hypothesis on ballistic addition of velocities, but at the present time this idea is not taken seriously. Practically none of the serious contemporary critics of STR, apart, of course, from amateurs, holds this point of view. The result cannot be considered as a direct experimental confirmation of the second postulate of Einstein's special theory of relativity, i.e., its main part, which speaks of the constancy of the velocity of light in all inertial reference frames, but only of that part which speaks of the independence of the velocity of light on motion of the source. Moreover, this same result stands as equal proof of the so-called theory of the luminiferous ether, which held sway up to the creation of the special theory of relativity and which has now been revived, i.e., it does not distinguish between these two theories. It is fundamentally impossible in principle to measure the velocity of light by the proposed method, it is only possible to postulate it.

  18. Measurements of the laminar burning velocity of hydrogen-air premixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Pareja, Jhon; Burbano, Hugo J. [Science and Technology of Gases and Rational Use of Energy Group, Faculty of Engineering, University of Antioquia, Calle 67 N 53, 108 Bloque 20, 447 Medellin (Colombia); Ogami, Yasuhiro [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)

    2010-02-15

    Experimental and numerical studies on laminar burning velocities of hydrogen-air mixtures were performed at standard pressure and room temperature varying the equivalence ratio from 0.8 to 3.0. The flames were generated using a contoured slot-type nozzle burner (4 mm x 10 mm). Measurements of laminar burning velocity were conducted using particle tracking velocimetry (PTV) combined with Schlieren photography. This technique provides the information of instantaneous local burning velocities in the whole region of the flame front, and laminar burning velocities were determined using the mean value of local burning velocities in the region of non-stretch. Additionally, average laminar burning velocities were determined using the angle method and compared with the data obtained with the PTV method. Numerical calculations were also conducted using detailed reaction mechanisms and transport properties. The experimental results from the PTV method are in good agreement with the numerical results at every equivalence ratio of the range of study. Differences between the results obtained with the angle method and those with the PTV method are reasonably small when the effects of flame stretch and curvature are reduced by using a contoured slot-type nozzle. (author)

  19. The in situ permeable flow sensor: A device for measuring groundwater flow velocity

    International Nuclear Information System (INIS)

    Ballard, S.; Barker, G.T.; Nichols, R.L.

    1994-03-01

    A new technology called the In Situ Permeable Flow Sensor has been developed at Sandia National Laboratories. These sensors use a thermal perturbation technique to directly measure the direction and magnitude of the full three dimensional groundwater flow velocity vector in unconsolidated, saturated, porous media. The velocity measured is an average value characteristic of an approximately 1 cubic meter volume of the subsurface. During a test at the Savannah River Site in South Carolina, two flow sensors were deployed in a confined aquifer in close proximity to a well which was screened over the entire vertical extent of the aquifer and the well was pumped at four different pumping rates. In this situation horizontal flow which is radially directed toward the pumping well is expected. The flow sensors measured horizontal flow which was directed toward the pumping well, within the uncertainty in the measurements. The observed magnitude of the horizontal component of the flow velocity increased linearly with pumping rate, as predicted by theoretical considerations. The measured horizontal component of the flow velocity differed from the predicted flow velocity, which was calculated with the assumptions that the hydraulic properties of the aquifer were radially homogeneous and isotropic, by less than a factor of two. Drawdown data obtained from other wells near the pumping well during the pump test indicate that the hydraulic properties of the aquifer are probably not radially homogeneous but the effect of the inhomogeneity on the flow velocity field around the pumping well was not modeled because the degree and distribution of the inhomogeneity are unknown. Grain size analysis of core samples from wells in the area were used to estimate the vertical distribution of hydraulic conductivity

  20. Measurement of Aortic Pulse Wave Velocity With a Connected Bathroom Scale.

    Science.gov (United States)

    Campo, David; Khettab, Hakim; Yu, Roger; Genain, Nicolas; Edouard, Paul; Buard, Nadine; Boutouyrie, Pierre

    2017-09-01

    Measurement of arterial stiffness should be more available. Our aim was to show that aortic pulse wave velocity can be reliably measured with a bathroom scale combining the principles of ballistocardiography (BCG) and impedance plethysmography on a single foot. The calibration of the bathroom scale was conducted on a group of 106 individuals. The aortic pulse wave velocity was measured with the SphygmoCor in the supine position. Three consecutive measurements were then performed on the Withings scale in the standing position. This aorta-leg pulse transit time (alPTT) was then converted into a velocity with the additional input of the height of the person. Agreement between the SphygmoCor and the bathroom scale so calibrated is assessed on a separate group of 86 individuals, following the same protocol. The bias is 0.25 m·s-1 and the SE 1.39 m·s-1. This agreement with Sphygmocor is "acceptable" according to the ARTERY classification. The alPTT correlated well with cfPTT with (Spearman) R = 0.73 in pooled population (cal 0.79, val 0.66). The aorta-leg pulse wave velocity correlated with carotid-femoral pulse wave velocity with R = 0.76 (cal 0.80, val 0.70). Estimation of the aortic pulse wave velocity is feasible with a bathroom scale. Further investigations are needed to improve the repeatability of measurements and to test their accuracy in different populations and conditions. © The Author 2017. Published by Oxford University Press on behalf of American Journal of Hypertension.

  1. Runoff velocity behaviour on smooth pavement and paving blocks surfaces measured by a tilted plot

    Directory of Open Access Journals (Sweden)

    Sedyowati Laksni

    2017-06-01

    Full Text Available Paving blocks have been widely known as an alternative technology for reducing runoff discharge due to their infiltration performance and capability of retarding the flow. Surface configuration of the different paving blocks types and the openings area play important role in decreasing the runoff velocity. In this study, we investigated the surface runoff velocity on two types of paving blocks layers, and a smooth pavement as comparison. The paving blocks type were rectangular blocks, which have 3.2% openings ratio and hexagonal blocks, which have 6.5% openings ratio. We used a tilted plot covering area of 2 × 6 m, equipped by a rainfall simulator to accommodate the variation of surface slope and rainfall intensity. We measured the velocity by using modification of dye tracer and buoyancy method. The data were then tabulated and graphed based on the paving types and the surface slopes. Generally, the velocity-slope relationship has demonstrated that the increase in surface slope leads to the increase in velocity. In this study, the result showed that slope and rainfall intensity simultaneously influenced the velocity (F = 19.91 > Ftable = 5.14; P < 0.05. However, the findings of this study showed a weak relationship between the changes of surface slope and the changes of runoff velocity on the rectangular blocks (R2 = 0.38. The greater slope did not always invariably lead to the greater runoff velocity. It was likely that there was other predictor variable that was not identified before, and need to be further investigated.

  2. Elastic Wave Velocity Measurements on Mantle Peridotite at High Pressure and Temperature

    Science.gov (United States)

    Mistler, G. W.; Ishikawa, M.; Li, B.

    2002-12-01

    With the success of conducting ultrasonic measurements at high pressure and high temperature in large volume high pressure apparatus with in-situ measurement of the sample length by X-ray imaging, it is now possible to measure elastic wave velocities on aggregate samples with candidate compositions of the mantle to the conditions of the Earth's transition zone in the laboratory. These data can be directly compared with seismic data to distinguish the compositional models in debate. In this work, we carried out velocity measurements on natural peridotite KLB-1 at the conditions of the Earth's upper mantle. Fine powered sample of natural KLB-1 was used as starting material. Specimens for ultrasonic measurements were hot-pressed and equilibrated at various pressure and temperature conditions along geotherm up to the transition zone. The recovered samples were characterized with density measurement, X-ray diffraction and microprobe analysis. Bench top P and S wave velocities of KLB-1 sample sintered at 3-4 GPa and 1400 degree centigrade showed a very good agreement with the VRH average of pyrolite. High pressure and high temperature measurements was conducted up to 7 GPa and 800 degree centigrade using ultrasonic interferometric method in a DIA-type high pressure apparatus in conjunction with X-ray diffraction and X-ray imaging. The utilization of X-ray imaging technique provides direct measurements of sample lengths at high pressure and high temperature, ensuring a precise determination of velocities. The results of P and S wave velocities at high pressure and high temperature as well as their comparison with calculated pyrolite model will be presented.

  3. MR velocity mapping measurement of renal artery blood flow in patients with impaired kidney function

    DEFF Research Database (Denmark)

    Cortsen, M; Petersen, L.J.; Stahlberg, F

    1996-01-01

    Renal blood flow (RBF) was measured in 9 patients with chronic impaired kidney function using MR velocity mapping and compared to PAH clearance and 99mTc-DTPA scintigraphy. An image plane suitable for flow measurement perpendicular to the renal arteries was chosen from 2-dimensional MR angiography....... MR velocity mapping was performed in both renal arteries using an ECG-triggered gradient echo pulse sequence previously validated in normal volunteers. Effective renal plasma flow was calculated from the clearance rate of PAH during constant infusion and the split of renal function was evaluated...... by 99mTc-DTPA scintigraphy. A reduction of RBF was found, and there was a significant correlation between PAH clearance multiplied by 1/(1-hematocrit) and RBF determined by MR velocity mapping. Furthermore, a significant correlation between the distribution of renal function and the percent distribution...

  4. Two-phase velocity measurements around cylinders using particle image velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Y.A.; Philip, O.G.; Schmidl, W.D. [Texas A& M Univ., College Station, TX (United States)] [and others

    1995-09-01

    The particle Image Velocimetry flow measurement technique was used to study both single-phase flow and two-phase flow across a cylindrical rod inserted in a channel. First, a flow consisting of only a single-phase fluid was studied. The experiment consisted of running a laminar flow over four rods inserted in a channel. The water flow rate was 126 cm{sup 3}/s. Then a two-phase flow was studied. A mixture of water and small air bubbles was used. The water flow rate was 378 cm{sup 3}/s and the air flow rate was approximately 30 cm{sup 3}/s. The data are analyzed to obtain the velocity fields for both experiments. After interpretation of the velocity data, forces acting on a bubble entrained by the vortex were calculated successfully. The lift and drag coefficients were calculated using the velocity measurements and the force data.

  5. Measurement of velocity field in pipe with classic twisted tape using matching refractive index technique

    Energy Technology Data Exchange (ETDEWEB)

    Song, Min Seop; Park, So Hyun; Kim, Eung Soo [Seoul National Univ., Seoul (Korea, Republic of)

    2014-10-15

    Many researchers conducted experiments and numerical simulations to measure or predict a Nusselt number or a friction factor in a pipe with a twisted tape while some other studies focused on the heat transfer performance enhancement using various twisted tape configurations. However, since the optical access to the inner space of a pipe with a twisted tape was limited, the detailed flow field data were not obtainable so far. Thus, researchers mainly relied on the numerical simulations to obtain the data of the flow field. In this study, a 3D printing technique was used to manufacture a transparent test section for optical access. And also, a noble refractive index matching technique was used to eliminate optical distortion. This two combined techniques enabled to measure the velocity profile with Particle Image Velocimetry (PIV). The measured velocity field data can be used either to understand the fundamental flow characteristics around a twisted tape or to validate turbulence models in Computational Fluid Dynamics (CFD). In this study, the flow field in the test-section was measured for various flow conditions and it was finally compared with numerically calculated data. Velocity fields in a pipe with a classic twisted tape was measured using a particle image velocimetry (PIV) system. To obtain undistorted particle images, a noble optical technique, refractive index matching, was used and it was proved that high-quality image can be obtained from this experimental equipment. The velocity data from the PIV was compared with the CFD simulations.

  6. Local velocity measurements in lead-bismuth and sodium flows using the ultrasound doppler velocimetry

    International Nuclear Information System (INIS)

    Eckert, S.; Gerbeth, G.

    2003-01-01

    We will present measurements of the velocity profiles in liquid sodium and eutectic lead-bismuth by means of the Ultrasonic Doppler Velocimetry (UDV). A sodium flow in a rectangular duct exposed to an external, transverse magnetic field has been examined. To demonstrate the capability of UDV the transformation of the well-known turbulent, piston-like profile to an M-shaped velocity profile for growing magnetic field strength was observed. The significance of artifacts such as caused by the existence of reflecting interfaces in the measuring domain will be discussed. In the sodium case, the measurements were performed through the channel wall. An integrated ultrasonic sensor with acoustic wave-guide has been developed to overcome the limitation of ultrasonic transducers to temperatures lower than 200 .deg. C. This sensor can presently be applied at maximum temperatures up to 800 .deg. C. Stable and robust measurements have been performed in various PbBi flows in our laboratory at FZR as well as at the THESYS loop of the KALLA laboratory of the ForschungsZentrum Karlsruhe (FZK). We will also present experimental results obtained in a PbBi bubbly flow at 250...300 .deg. C. Argon bubbles were injected through a single orifice in a cylindrical container filled with stagnant PbBi. Velocity profiles were measured in the bubble plume. Mean values of the liquid as well as the bubble velocity were extracted from the data and will be presented as function of the gas flow rate

  7. Measurement of velocity field in pipe with classic twisted tape using matching refractive index technique

    International Nuclear Information System (INIS)

    Song, Min Seop; Park, So Hyun; Kim, Eung Soo

    2014-01-01

    Many researchers conducted experiments and numerical simulations to measure or predict a Nusselt number or a friction factor in a pipe with a twisted tape while some other studies focused on the heat transfer performance enhancement using various twisted tape configurations. However, since the optical access to the inner space of a pipe with a twisted tape was limited, the detailed flow field data were not obtainable so far. Thus, researchers mainly relied on the numerical simulations to obtain the data of the flow field. In this study, a 3D printing technique was used to manufacture a transparent test section for optical access. And also, a noble refractive index matching technique was used to eliminate optical distortion. This two combined techniques enabled to measure the velocity profile with Particle Image Velocimetry (PIV). The measured velocity field data can be used either to understand the fundamental flow characteristics around a twisted tape or to validate turbulence models in Computational Fluid Dynamics (CFD). In this study, the flow field in the test-section was measured for various flow conditions and it was finally compared with numerically calculated data. Velocity fields in a pipe with a classic twisted tape was measured using a particle image velocimetry (PIV) system. To obtain undistorted particle images, a noble optical technique, refractive index matching, was used and it was proved that high-quality image can be obtained from this experimental equipment. The velocity data from the PIV was compared with the CFD simulations

  8. Bayesian Integrated Data Analysis of Fast-Ion Measurements by Velocity-Space Tomography

    DEFF Research Database (Denmark)

    Salewski, M.; Nocente, M.; Jacobsen, A.S.

    2018-01-01

    Bayesian integrated data analysis combines measurements from different diagnostics to jointly measure plasma parameters of interest such as temperatures, densities, and drift velocities. Integrated data analysis of fast-ion measurements has long been hampered by the complexity of the strongly non...... framework. The implementation for different types of diagnostics as well as the uncertainties are discussed, and we highlight the importance of integrated data analysis of all available detectors....

  9. Inertial Navigation System/Doppler Velocity Log (INS/DVL Fusion with Partial DVL Measurements

    Directory of Open Access Journals (Sweden)

    Asaf Tal

    2017-02-01

    Full Text Available The Technion autonomous underwater vehicle (TAUV is an ongoing project aiming to develop and produce a small AUV to carry on research missions, including payload dropping, and to demonstrate acoustic communication. Its navigation system is based on an inertial navigation system (INS aided by a Doppler velocity log (DVL, magnetometer, and pressure sensor (PS. In many INSs, such as the one used in TAUV, only the velocity vector (provided by the DVL can be used for aiding the INS, i.e., enabling only a loosely coupled integration approach. In cases of partial DVL measurements, such as failure to maintain bottom lock, the DVL cannot estimate the vehicle velocity. Thus, in partial DVL situations no velocity data can be integrated into the TAUV INS, and as a result its navigation solution will drift in time. To circumvent that problem, we propose a DVL-based vehicle velocity solution using the measured partial raw data of the DVL and additional information, thereby deriving an extended loosely coupled (ELC approach. The implementation of the ELC approach requires only software modification. In addition, we present the TAUV six degrees of freedom (6DOF simulation that includes all functional subsystems. Using this simulation, the proposed approach is evaluated and the benefit of using it is shown.

  10. Hyperacusis Questionnaire as a Tool for Measuring Hypersensitivity to Sound in a Tinnitus Research Population

    Directory of Open Access Journals (Sweden)

    Kathryn Fackrell

    2015-01-01

    Full Text Available Hypersensitivity to external sounds is often comorbid with tinnitus and may be significant for adherence to certain types of tinnitus management. Therefore, a clear measure of sensitivity to sound is important. The aim of this study was to evaluate the validity and reliability of the Hyperacusis Questionnaire (HQ for use as a measurement tool using data from a sample of 264 adults who took part in tinnitus research. We evaluated the HQ factor structure, internal consistency, convergent and discriminant validity, and floor and ceiling effects. Internal consistency was high (Cronbach’s alpha = 0.88 and moderate correlations were observed between the HQ, uncomfortable loudness levels, and other health questionnaires. Confirmatory factor analysis revealed that the original HQ three-factor solution and a one-factor solution were both a poor fit to the data. Four problematic items were removed and exploratory factor analysis identified a two-factor (attentional and social solution. The original three-factor structure of the HQ was not confirmed. All fourteen items do not accurately assess hypersensitivity to sound in a tinnitus population. We propose a 10-item (2-factor version of the HQ, which will need to be confirmed using a new tinnitus and perhaps nontinnitus population.

  11. Hyperacusis Questionnaire as a Tool for Measuring Hypersensitivity to Sound in a Tinnitus Research Population.

    Science.gov (United States)

    Fackrell, Kathryn; Fearnley, Constance; Hoare, Derek J; Sereda, Magdalena

    2015-01-01

    Hypersensitivity to external sounds is often comorbid with tinnitus and may be significant for adherence to certain types of tinnitus management. Therefore, a clear measure of sensitivity to sound is important. The aim of this study was to evaluate the validity and reliability of the Hyperacusis Questionnaire (HQ) for use as a measurement tool using data from a sample of 264 adults who took part in tinnitus research. We evaluated the HQ factor structure, internal consistency, convergent and discriminant validity, and floor and ceiling effects. Internal consistency was high (Cronbach's alpha = 0.88) and moderate correlations were observed between the HQ, uncomfortable loudness levels, and other health questionnaires. Confirmatory factor analysis revealed that the original HQ three-factor solution and a one-factor solution were both a poor fit to the data. Four problematic items were removed and exploratory factor analysis identified a two-factor (attentional and social) solution. The original three-factor structure of the HQ was not confirmed. All fourteen items do not accurately assess hypersensitivity to sound in a tinnitus population. We propose a 10-item (2-factor) version of the HQ, which will need to be confirmed using a new tinnitus and perhaps nontinnitus population.

  12. Measurement system of bubbly flow using ultrasonic velocity profile monitor and video data processing unit

    International Nuclear Information System (INIS)

    Aritomi, Masanori; Zhou, Shirong; Nakajima, Makoto; Takeda, Yasushi; Mori, Michitsugu; Yoshioka, Yuzuru.

    1996-01-01

    The authors have been developing a measurement system for bubbly flow in order to clarify its multi-dimensional flow characteristics and to offer a data base to validate numerical codes for multi-dimensional two-phase flow. In this paper, the measurement system combining an ultrasonic velocity profile monitor with a video data processing unit is proposed, which can measure simultaneously velocity profiles in both gas and liquid phases, a void fraction profile for bubbly flow in a channel, and an average bubble diameter and void fraction. Furthermore, the proposed measurement system is applied to measure flow characteristics of a bubbly countercurrent flow in a vertical rectangular channel to verify its capability. (author)

  13. Flow velocity measurement by using zero-crossing polarity cross correlation method

    International Nuclear Information System (INIS)

    Xu Chengji; Lu Jinming; Xia Hong

    1993-01-01

    Using the designed correlation metering system and a high accurate hot-wire anemometer as a calibration device, the experimental study of correlation method in a tunnel was carried out. The velocity measurement of gas flow by using zero-crossing polarity cross correlation method was realized and the experimental results has been analysed

  14. A simple measurement method of molecular relaxation in a gas by reconstructing acoustic velocity dispersion

    Science.gov (United States)

    Zhu, Ming; Liu, Tingting; Zhang, Xiangqun; Li, Caiyun

    2018-01-01

    Recently, a decomposition method of acoustic relaxation absorption spectra was used to capture the entire molecular multimode relaxation process of gas. In this method, the acoustic attenuation and phase velocity were measured jointly based on the relaxation absorption spectra. However, fast and accurate measurements of the acoustic attenuation remain challenging. In this paper, we present a method of capturing the molecular relaxation process by only measuring acoustic velocity, without the necessity of obtaining acoustic absorption. The method is based on the fact that the frequency-dependent velocity dispersion of a multi-relaxation process in a gas is the serial connection of the dispersions of interior single-relaxation processes. Thus, one can capture the relaxation times and relaxation strengths of N decomposed single-relaxation dispersions to reconstruct the entire multi-relaxation dispersion using the measurements of acoustic velocity at 2N  +  1 frequencies. The reconstructed dispersion spectra are in good agreement with experimental data for various gases and mixtures. The simulations also demonstrate the robustness of our reconstructive method.

  15. Planar measurements of velocity and concentration of turbulent mixing in a T-junction

    DEFF Research Database (Denmark)

    Ingvorsen, Kristian Mark; Meyer, Knud Erik; Nielsen, N. F.

    Turbulent mixing of two isothermal air streams in a T-junction of square ducts are investigated. Three dimensional velocity fields and turbulent kinetic energy are measured with stereoscopic Particle Image Velocimetry (PIV). The concentration field is obtained with a planar Mie scattering technique...

  16. Viscosity estimation utilizing flow velocity field measurements in a rotating magnetized plasma

    International Nuclear Information System (INIS)

    Yoshimura, Shinji; Tanaka, Masayoshi Y.

    2008-01-01

    The importance of viscosity in determining plasma flow structures has been widely recognized. In laboratory plasmas, however, viscosity measurements have been seldom performed so far. In this paper we present and discuss an estimation method of effective plasma kinematic viscosity utilizing flow velocity field measurements. Imposing steady and axisymmetric conditions, we derive the expression for radial flow velocity from the azimuthal component of the ion fluid equation. The expression contains kinematic viscosity, vorticity of azimuthal rotation and its derivative, collision frequency, azimuthal flow velocity and ion cyclotron frequency. Therefore all quantities except the viscosity are given provided that the flow field can be measured. We applied this method to a rotating magnetized argon plasma produced by the Hyper-I device. The flow velocity field measurements were carried out using a directional Langmuir probe installed in a tilting motor drive unit. The inward ion flow in radial direction, which is not driven in collisionless inviscid plasmas, was clearly observed. As a result, we found the anomalous viscosity, the value of which is two orders of magnitude larger than the classical one. (author)

  17. On measuring surface wave phase velocity from station–station cross-correlation of ambient signal

    DEFF Research Database (Denmark)

    Boschi, Lapo; Weemstra, Cornelis; Verbeke, Julie

    2012-01-01

    We apply two different algorithms to measure surface wave phase velocity, as a function of frequency, from seismic ambient noise recorded at pairs of stations from a large European network. The two methods are based on consistent theoretical formulations, but differ in the implementation: one met...

  18. Recovery of Stokes waves from velocity measurements on an axis of symmetry

    International Nuclear Information System (INIS)

    Matioc, Bogdan-Vasile

    2015-01-01

    We provide a new method to recover the profile of Stokes waves, and more generally of waves with smooth vorticity, from measurements of the horizontal velocity component on a vertical axis of symmetry of the wave surface. Although we consider periodic waves only, the extension to solitary waves is straightforward. (paper)

  19. Velocity flow field and water level measurements in shoaling and breaking water waves

    CSIR Research Space (South Africa)

    Mukaro, R

    2010-01-01

    Full Text Available In this paper we report on the laboratory investigations of breaking water waves. Measurements of the water levels and instantaneous fluid velocities were conducted in water waves breaking on a sloping beach within a glass flume. Instantaneous water...

  20. Velocity field measurements in an evaporating sessile droplet by means of micro-PIV technique

    Directory of Open Access Journals (Sweden)

    Yagodnitsyna Anna

    2016-01-01

    Full Text Available Velocity fields are measured in evaporating sessile droplets on two substrates with different contact angles and contact angle hysteresis using micro resolution particle image velocimetry technique. Different flow patterns are observed in different stages of droplet evaporation: a flow with vortices and a radial flow. Flow structure is found to be similar for droplets on different substrates.

  1. Sound intensity

    DEFF Research Database (Denmark)

    Crocker, Malcolm J.; Jacobsen, Finn

    1998-01-01

    This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique.......This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique....

  2. Sound Intensity

    DEFF Research Database (Denmark)

    Crocker, M.J.; Jacobsen, Finn

    1997-01-01

    This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique.......This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique....

  3. Galileo, measurement of the velocity of light, and the reaction times.

    Science.gov (United States)

    Foschi, Renato; Leone, Matteo

    2009-01-01

    According to the commonly accepted view, Galileo Galilei devised in 1638 an experiment that seemed able to show that the velocity of light is finite. An analysis of archival material shows that two decades later members of the Florence scientific society Accademia del Cimento followed Galileo guidelines by actually attempting to measure the velocity of light and suggesting improvements. This analysis also reveals a fundamental difference between Galileo's and Florence academy's methodologies and that Galileo's experiment was, in some respects, a pioneering work affecting also the history of the psychology of perception.

  4. A 4-spot time-of-flight anemometer for small centrifugal compressor velocity measurements

    Science.gov (United States)

    Wernet, Mark P.; Skoch, Gary J.

    1992-01-01

    The application of laser anemometry techniques in turbomachinery facilities is a challenging dilemma requiring an anemometer system with special qualities. Here, we describe the use of a novel laser anemometry technique applied to a small 4.5 kg/s, 4:1 pressure ratio centrifugal compressor. Sample velocity profiles across the blade pitch are presented for a single location along the rotor. The results of the intra-blade passage velocity measurements will ultimately be used to verify CFD 3-D viscous code predictions.

  5. Measuring the Bed Load velocity in Laboratory flumes using ADCP and Digital Cameras

    Science.gov (United States)

    Conevski, Slaven; Guerrero, Massimo; Rennie, Colin; Bombardier, Josselin

    2017-04-01

    Measuring the transport rate and apparent velocity of the bedload is notoriously hard and there is not a certain technique that would obtain continues data. There are many empirical models, based on the estimation of the shear stress, but only few involve direct measurement of the bed load velocity. The bottom tracking (BT) mode of an acoustic Doppler current profiler (ADCP) has been used many times to estimate the apparent velocity of the bed load. Herein is the basic idea, to exploit the bias of the BT signal towards the bed load movement and to calibrate this signal with traditional measuring techniques. These measurements are quite scarce and seldom reliable since there are not taken in controlled conditions. So far, no clear confirmation has been conducted in laboratory-controlled conditions that would attest the assumptions made in the estimation of the apparent bed load velocity, nor in the calibration of the empirical equations. Therefore, this study explores several experiments under stationary conditions, where the signal of the ADCP BT mode is recorded and compared to the bed load motion recorded by digital camera videography. The experiments have been performed in the hydraulic laboratories of Ottawa and Bologna, using two different ADCPs and two different high resolution cameras. In total, more then 30 experiments were performed for different sediment mixtures and different hydraulic conditions. In general, a good match is documented between the apparent bed load velocity measured by the ADCP and the videography. The slight deviation in single experiments can be explained by gravel particles inhomogeneity, difficult in reproducing the same hydro-sedimentological conditions and the randomness of the backscattering strength.

  6. Point Measurements of Fermi Velocities by a Time-of-Flight Method

    DEFF Research Database (Denmark)

    Falk, David S.; Henningsen, J. O.; Skriver, Hans Lomholt

    1972-01-01

    The present paper describes in detail a new method of obtaining information about the Fermi velocity of electrons in metals, point by point, along certain contours on the Fermi surface. It is based on transmission of microwaves through thin metal slabs in the presence of a static magnetic field...... applied parallel to the surface. The electrons carry the signal across the slab and arrive at the second surface with a phase delay which is measured relative to a reference signal; the velocities are derived by analyzing the magnetic field dependence of the phase delay. For silver we have in this way...... obtained one component of the velocity along half the circumference of the centrally symmetric orbit for B→∥[100]. The results are in agreement with current models for the Fermi surface. For B→∥[011], the electrons involved are not moving in a symmetry plane of the Fermi surface. In such cases one cannot...

  7. Direct measurements of the velocity and thickness of ''explosively'' propagating buried molten layers in amorphous silicon

    International Nuclear Information System (INIS)

    Lowndes, D.H.; Jellison, G.E. Jr.; Pennycook, S.J.; Withrow, S.P.; Mashburn, D.N.

    1986-01-01

    Simultaneous infrared (1152 nm) and visible (633 nm) reflectivity measurements with nanosecond resolution were used to study the initial formation and subsequent motion of pulsed KrF laser-induced ''explosively'' propagating buried molten layers in ion implantation-amorphized silicon. The buried layer velocity decreases with depth below the surface, but increases with KrF laser energy density; a maximum velocity of about 14 m/s was observed, implying an undercooling-velocity relationship of approx. 14 K/(m/s). Z-contrast scanning transmission electron microscopy was used to form a direct chemical image of implanted Cu ions transported by the buried layer and showed that the final buried layer thickness was <15 nm

  8. PIV measurements of velocities and accelerations under breaking waves on a slope

    DEFF Research Database (Denmark)

    Vested, Malene Hovgaard; Carstensen, Stefan; Christensen, Erik Damgaard

    2017-01-01

    waves. In this study, we have investigated the wave kinematics under steep and breaking waves on a laboratory beach with a slope of 1/25. The velocity field was measured by use of Particle Image Velocimetry (PIV) at a sample rate of 96Hz. The high sample rate allowed for the accelerations...... to be determined directly from the sampled velocities. It was found that both velocities and accelerations differ from the ones predicted from common wave theories such as streamfunction theory. This was especially evident at the top part of the wave close to the surface. This was not surprising, since...... the breaking event is a highly non-linear process. The results presented here may facilitate computations of the impact force on offshore structures and furthermore be used for validation of CFD models while altogether shedding light on the mechanisms behind breaking waves....

  9. Magnetic phase diagram of Ba3CoSb2O9 as determined by ultrasound velocity measurements

    Science.gov (United States)

    Quirion, G.; Lapointe-Major, M.; Poirier, M.; Quilliam, J. A.; Dun, Z. L.; Zhou, H. D.

    2015-07-01

    Using high-resolution sound velocity measurements we have obtained a very precise magnetic phase diagram of Ba3CoSb2O9 , a material that is considered to be an archetype of the spin-1/2 triangular-lattice antiferromagnet. Results obtained for the field parallel to the basal plane (up to 18 T) show three phase transitions, consistent with predictions based on simple two-dimensional isotropic Heisenberg models and previous experimental investigations. The phase diagram obtained for the field perpendicular to the basal plane clearly reveals an easy-plane character of this compound and, in particular, our measurements show a single first-order phase transition at Hc 1=12.0 T which can be attributed to a spin flop between an umbrella-type configuration and a coplanar V -type order where spins lie in a plane perpendicular to the a b plane. At low temperatures, softening of the lattice within some of the ordered phases is also observed and may be a result of residual spin fluctuations.

  10. Development of three-dimensional individual bubble-velocity measurement method by bubble tracking

    International Nuclear Information System (INIS)

    Kanai, Taizo; Furuya, Masahiro; Arai, Takahiro; Shirakawa, Kenetsu; Nishi, Yoshihisa

    2012-01-01

    A gas-liquid two-phase flow in a large diameter pipe exhibits a three-dimensional flow structure. Wire-Mesh Sensor (WMS) consists of a pair of parallel wire layers located at the cross section of a pipe. Both the parallel wires cross at 90o with a small gap and each intersection acts as an electrode. The WMS allows the measurement of the instantaneous two-dimensional void-fraction distribution over the cross-section of a pipe, based on the difference between the local instantaneous conductivity of the two-phase flow. Furthermore, the WMS can acquire a phasic-velocity on the basis of the time lag of void signals between two sets of WMS. Previously, the acquired phasic velocity was one-dimensional with time-averaged distributions. The authors propose a method to estimate the three-dimensional bubble-velocity individually WMS data. The bubble velocity is determined by the tracing method. In this tracing method, each bubble is separated from WMS signal, volume and center coordinates of the bubble is acquired. Two bubbles with near volume at two WMS are considered as the same bubble and bubble velocity is estimated from the displacement of the center coordinates of the two bubbles. The validity of this method is verified by a swirl flow. The proposed method can successfully visualize a swirl flow structure and the results of this method agree with the results of cross-correlation analysis. (author)

  11. Development of three-dimensional phasic-velocity distribution measurement in a large-diameter pipe

    International Nuclear Information System (INIS)

    Kanai, Taizo; Furuya, Masahiro; Arai, Takahiro; Shirakawa, Kenetsu

    2011-01-01

    A wire-mesh sensor (WMS) can acquire a void fraction distribution at a high temporal and spatial resolution and also estimate the velocity of a vertical rising flow by investigating the signal time-delay of the upstream WMS relative to downstream. Previously, one-dimensional velocity was estimated by using the same point of each WMS at a temporal resolution of 1.0 - 5.0 s. The authors propose to extend this time series analysis to estimate the multi-dimensional velocity profile via cross-correlation analysis between a point of upstream WMS and multiple points downstream. Bubbles behave in various ways according to size, which is used to classify them into certain groups via wavelet analysis before cross-correlation analysis. This method was verified by air-water straight and swirl flows within a large-diameter vertical pipe. The results revealed that for the rising straight and swirl flows, large scale bubbles tend to move to the center, while the small bubble is pushed to the outside or sucked into the space where the large bubbles existed. Moreover, it is found that this method can estimate the rotational component of velocity of the swirl flow as well as measuring the multi-dimensional velocity vector at high temporal resolutions of 0.2s. (author)

  12. The spatial filtering method for solid particle velocity measurement based on an electrostatic sensor

    International Nuclear Information System (INIS)

    Xu, Chuanlong; Tang, Guanghua; Zhou, Bin; Wang, Shimin

    2009-01-01

    The spatial filtering method for particle velocity measurement has the advantages of simplicity of the measurement system and convenience of data processing. In this paper, the relationship between solid particles mean velocity in a pneumatic pipeline and the power spectrum of the output signal of an electrostatic sensor was mathematically modeled. The effects of the length of the sensor, the thickness of the dielectric pipe and its length on the spatial filtering characteristics of the sensor were also investigated using the finite element method. As for the roughness of and the difficult determination of the peak frequency f max of the power spectrum characteristics of the output signal of the sensor, a wavelet analysis based filtering method was applied to smooth the curve, which can accurately determine the peak frequency f max . Finally, experiments were performed on a pilot dense phase pneumatic conveying rig at high pressure to test the performance of the velocity measurement system. The experimental results show that the system repeatability is within ±4% over a gas superficial velocity range of 8.63–18.62 m s −1 for a particle concentration range of 0.067–0.130 m 3 m −3

  13. Measurement of the near-wall velocity profile for a nanofluid flow inside a microchannel

    Science.gov (United States)

    Kanjirakat, Anoop; Sadr, Reza

    2015-11-01

    Hydrodynamics and anomalous heat transfer enhancements have been reported in the past for colloidal suspensions of nano-sized particles dispersed in a fluid (nanofluids). However, such augmentations may manifest itself by study of fluid flow characteristics near in the wall region. Present experimental study reports near-wall velocity profile for nanofluids (silicon dioxide nanoparticles in water) measured inside a microchannel. An objective-based nano-Particle Image Velocimetry (nPIV) technique is used to measure fluid velocity within three visible depths, O(100nm), from the wall. The near-wall fluid velocity profile is estimated after implementing the required corrections for optical properties and effects caused by hindered Brownian motion, wall-particle interactions, and non-uniform exponential illumination on the measurement technique. The fluid velocities of nanofluids at each of the three visible depths are observed to be higher than that of the base fluid resulting in a higher shear rate in this region. The relative increase in shear rates for nanofluids is believed to be the result of the near-wall shear-induced particle migration along with the Brownian motion of the nanoparticles. This research is funded by NPRP grant # 08-574-2-239 from the Qatar National Research Fund (a member of Qatar Foundation).

  14. High-magnification velocity field measurements on high-frequency, supersonic microactuators

    Science.gov (United States)

    Kreth, Phil; Fernandez, Erik; Ali, Mohd; Alvi, Farrukh

    2014-11-01

    The Resonance-Enhanced Microjet (REM) actuator developed at our laboratory produces pulsed, supersonic microjets by utilizing a number of microscale, flow-acoustic resonance phenomena. The microactuator used in this study consists of an underexpanded source jet flowing into a cylindrical cavity with a single orifice through which an unsteady, supersonic jet issues at a resonant frequency of 7 kHz. The flowfields of a 1 mm underexpanded free jet and the microactuator are studied in detail using high-magnification, phase-locked flow visualizations (microschlieren) and 2-component particle image velocimetry. The challenges of these measurements at such small scales and supersonic velocities are discussed. The results clearly show that the microactuator produces supersonic pulsed jets with velocities exceeding 400 m/s. This is the first direct measurement of the velocity field and its temporal evolution produced by such actuators. Comparisons are made between the flow visualizations, velocity field measurements, and simulations using Implicit LES for a similar microactuator. With high, unsteady momentum output, this type of microactuator has potential in a range of flow control applications.

  15. Oceanic crustal velocities from laboratory and logging measurements of Integrated Ocean Drilling Program Hole 1256D

    Science.gov (United States)

    Gilbert, Lisa A.; Salisbury, Matthew H.

    2011-09-01

    Drilling and logging of Integrated Ocean Drilling Program (IODP) Hole 1256D have provided a unique opportunity for systematically studying a fundamental problem in marine geophysics: What influences the seismic structure of oceanic crust, porosity or composition? Compressional wave velocities (Vp) logged in open hole or from regional refraction measurements integrate both the host rock and cracks in the crust. To determine the influence of cracks on Vp at several scales, we first need an accurate ground truth in the form of laboratory Vp on crack-free, or nearly crack-free samples. We measured Vp on 46 water-saturated samples at in situ pressures to determine the baseline velocities of the host rock. These new results match or exceed Vp logs throughout most of the hole, especially in the lower dikes and gabbros, where porosities are low. In contrast, samples measured at sea under ambient laboratory conditions, had consistently lower Vp than the Vp logs, even after correction to in situ pressures. Crack-free Vp calculated from simple models of logging and laboratory porosity data for different lithologies and facies suggest that crustal velocities in the lavas and upper dikes are controlled by porosity. In particular, the models demonstrate significant large-scale porosity in the lavas, especially in the sections identified as fractured flows and breccias. However, crustal velocities in the lower dikes and gabbros are increasingly controlled by petrology as the layer 2-3 boundary is approached.

  16. LOCAL VELOCITY PROFILES MEASURED BY PIV IN AN VESSEL AGITATED BY RUSHTON TURBINE

    Directory of Open Access Journals (Sweden)

    Radek Šulc

    2014-12-01

    Full Text Available The hydrodynamics and flow field were measured in an agitated vessel using 2-D Time Resolved Particle Image Velocimetry (2-D TR PIV. The experiments were carried out in a fully baffled cylindrical flat bottom vessel 300 mm in inner diameter. The tank was agitated by a Rushton turbine 100 mm in diameter. The velocity fields were measured for three impeller rotation speeds 300 rpm, 450 rpm and 600 rpm and the corresponding Reynolds numbers in the range 50 000 < Re < 100 000, which means that the fully-developed turbulent flow was reached. In accordance with the theory of mixing, the dimensionless mean and fluctuation velocities in the measured directions were found to be constant and independent of the impeller rotational speed. The velocity profiles were averaged, and were expressed by Chebyshev polynomials of the 1st order. Although the experimentally investigated area was relatively far from the impeller, and it was located in upward flow to the impeller, no state of local isotropy was found. The ratio of the axial rms fluctuation velocity to the radial component was found to be in the range from 0.523 to 0.768. The axial turbulence intensity was found to be in the range from 0.293 to 0.667, which corresponds to a high turbulence intensity.

  17. A generalized formulation for noise-based seismic velocity change measurements

    Science.gov (United States)

    Gómez-García, C.; Brenguier, F.; Boué, P.; Shapiro, N.; Droznin, D.; Droznina, S.; Senyukov, S.; Gordeev, E.

    2017-12-01

    The observation of continuous seismic velocity changes is a powerful tool for detecting seasonal variations in crustal structure, volcanic unrest, co- and post-seismic evolution of stress in fault areas or the effects of fluid injection. The standard approach for measuring such velocity changes relies on comparison of travel times in the coda of a set of seismic signals, usually noise-based cross-correlations retrieved at different dates, and a reference trace, usually a averaged function over dates. A good stability in both space and time of the noise sources is then the main assumption for reliable measurements. Unfortunately, these conditions are often not fulfilled, as it happens when ambient-noise sources are non-stationary, such as the emissions of low-frequency volcanic tremors.We propose a generalized formulation for retrieving continuous time series of noise-based seismic velocity changes without any arbitrary reference cross-correlation function. We set up a general framework for future applications of this technique performing synthetic tests. In particular, we study the reliability of the retrieved velocity changes in case of seasonal-type trends, transient effects (similar to those produced as a result of an earthquake or a volcanic eruption) and sudden velocity drops and recoveries as the effects of transient local source emissions. Finally, we apply this approach to a real dataset of noise cross-correlations. We choose the Klyuchevskoy volcanic group (Kamchatka) as a case study where the recorded wavefield is hampered by loss of data and dominated by strongly localized volcanic tremor sources. Despite the mentioned wavefield contaminations, we retrieve clear seismic velocity drops associated with the eruptions of the Klyuchevskoy an the Tolbachik volcanoes in 2010 and 2012, respectively.

  18. A software to measure phase-velocity dispersion from ambient-noise correlations and its application to the SNSN data

    Science.gov (United States)

    Sadeghisorkhani, Hamzeh; Gudmundsson, Ólafur

    2017-04-01

    Graphical software for phase-velocity dispersion measurements of surface waves in noise-correlation traces, called GSpecDisp, is presented. It is an interactive environment for the measurements and presentation of the results. It measures phase-velocity dispersion curves in the frequency domain based on matching of the real part of the cross-correlation spectrum with the appropriate Bessel function. The inputs are time-domain cross-correlations in SAC format. It can measure two types of phase-velocity dispersion curves; 1- average phase-velocity of a region, and 2- single-pair phase velocity. The average phase-velocity dispersion curve of a region can be used as a reference curve to automatically select the dispersion curves from each single-pair cross-correlation in that region. It also allows the users to manually refine the selections. Therefore, no prior knowledge is needed for an unknown region. GSpecDisp can measure the phase velocity of Rayleigh and Love waves from all possible components of the noise correlation tensor, including diagonal and off-diagonal components of the tensor. First, we explain how GSpecDisp is applied to measure phase-velocity dispersion curves. Then, we demonstrate measurement results on synthetic and real data from the Swedish National Seismic Network (SNSN). We compare the results with two other methods of phase-velocity dispersion measurements. Finally, we compare phase-velocity dispersion curves of Rayleigh waves obtained from different components of the correlation tensor.

  19. In-situ measurements of seismic velocities in the San Francisco Bay Region; part III

    Science.gov (United States)

    Gibbs, James F.; Fumal, Thomas E.; Borcherdt, Roger D.; Roth, Edward F.

    1977-01-01

    Seismic wave velocities (compressional and shear) are important parameters for estimating the seismic response characteristics of various geologic units when subjected to strong earthquake ground shaking. Seismic velocities of various units often show a strong correlation with the amounts of damage following large earthquakes and have been used as a basis for certain types of seismic zonation studies. In the current program seismic velocities have been measured at 59 locations 1n the San Francisco Bay Region. This report is the third in a series of Open-File Reports and describes the in-situ velocity measurements at locations 35-59. At each location seismic travel times are measured in drill holes, normally at 2.5-m intervals to a depth of 30 m. Geologic logs are determined from drill cuttings, undisturbed (cored) samples, and penetrometer samples. The data provide a detailed comparison of geologic and seismic characteristics and provide parameters for estimating strong earthquake ground motions quantitatively at each of the sites. A major emphasis of this program is to obtain a detailed comparison of geologic and seismic data on a regional scale for use in seismic zonation. There is a variety of geologic and seismic data available in the San Francisco Bay Region for use 1n developing the general zoning techniques which can then be applied to other areas. Shear wave velocities 1n near-surface geologic materials are of especial interest for engineering seismology and seismic zonation studies, yet in general, they are difficult to measure because of contamination by compressional waves. A comparison of various in-situ techniques by Warrick (1974) establishes the reliability of the method utilizing a "horizontal traction" source for sites underlain by bay mud and alluvium. Gibbs, and others (1975a) present data from 12 holes and establishes the reliability of the method for sites underlain by a variety of different rock units and suggest extending the measurements to

  20. Music and language expertise influence the categorization of speech and musical sounds: behavioral and electrophysiological measurements.

    Science.gov (United States)

    Elmer, Stefan; Klein, Carina; Kühnis, Jürg; Liem, Franziskus; Meyer, Martin; Jäncke, Lutz

    2014-10-01

    In this study, we used high-density EEG to evaluate whether speech and music expertise has an influence on the categorization of expertise-related and unrelated sounds. With this purpose in mind, we compared the categorization of speech, music, and neutral sounds between professional musicians, simultaneous interpreters (SIs), and controls in response to morphed speech-noise, music-noise, and speech-music continua. Our hypothesis was that music and language expertise will strengthen the memory representations of prototypical sounds, which act as a perceptual magnet for morphed variants. This means that the prototype would "attract" variants. This so-called magnet effect should be manifested by an increased assignment of morphed items to the trained category, by a reduced maximal slope of the psychometric function, as well as by differential event-related brain responses reflecting memory comparison processes (i.e., N400 and P600 responses). As a main result, we provide first evidence for a domain-specific behavioral bias of musicians and SIs toward the trained categories, namely music and speech. In addition, SIs showed a bias toward musical items, indicating that interpreting training has a generic influence on the cognitive representation of spectrotemporal signals with similar acoustic properties to speech sounds. Notably, EEG measurements revealed clear distinct N400 and P600 responses to both prototypical and ambiguous items between the three groups at anterior, central, and posterior scalp sites. These differential N400 and P600 responses represent synchronous activity occurring across widely distributed brain networks, and indicate a dynamical recruitment of memory processes that vary as a function of training and expertise.

  1. Neutrino velocity measurement with the OPERA experiment in the CNGS beam

    International Nuclear Information System (INIS)

    Brunetti, G.

    2011-05-01

    The thesis concerns the measurement of the neutrino velocity with the OPERA experiment in the CNGS beam. There are different theoretical models that allow for Lorentz violating effects which can be investigated with measurements on terrestrial neutrino beams. The MINOS experiment published in 2007 a measure on the muon neutrinos over a distance of 730 km finding a deviation with respect to the expected time of flight of 126 ns with a statistical error of 32 ns and a systematic error of 64 ns. The OPERA experiment observes as well muon neutrinos 730 km away from the source, with a sensitivity significantly better than MINOS thanks to the higher number of interactions in the detector due to the higher energy beam and the much more sophisticated timing system explicitly upgraded in view of the neutrino velocity measurement. This system is composed by atomic cesium clocks and GPS receivers operating in 'common view mode'. Thanks to this system a time-transfer between the two sites with a precision at the level of 1 ns is possible. Moreover, a Fast Waveform Digitizer was installed along the proton beam line at CERN in order to measure the internal time structure of the proton pulses that are sent to the CNGS target. The result on the neutrino velocity is the most precise measurement so far with terrestrial neutrino beams: the neutrino time of flight was determined with a statistical uncertainty of about 10 ns and a systematic uncertainty smaller than 20 nano-seconds. (author)

  2. Local measurement of interfacial area, interfacial velocity and liquid turbulence in two-phase flow

    International Nuclear Information System (INIS)

    Hibiki, T.; Hogsett, S.; Ishii, M.

    1998-01-01

    Double sensor probe and hotfilm anemometry methods were developed for measuring local flow characteristics in bubbly flow. The formulation for the interfacial area concentration measurement was obtained by improving the formulation derived by Kataoka and Ishii. The assumptions used in the derivation of the equation were verified experimentally. The interfacial area concentration measured by the double sensor probe agreed well with one by the photographic method. The filter to validate the hotfilm anemometry for measuring the liquid velocity and turbulent intensity in bubbly flow was developed based on removing the signal due to the passing bubbles. The local void fraction, interfacial area concentration, interfacial velocity, Sauter mean diameter, liquid velocity, and turbulent intensity of vertical upward air-water flow in a round tube with inner diameter of 50.8 mm were measured by using these methods. A total of 54 data sets were acquired consisting of three superficial gas flow rates, 0.039, 0.067, and 0.147 m/s, and three superficial liquid flow rates, 0.60, 1.00, and 1.30 m/s. The measurements were performed at the three locations: L/D=2, 32, and 62. This data is expected to be used for the development of reliable constitutive relations which reflect the true transfer mechanisms in two-phase flow. (author)

  3. Novel Volumetric Size and Velocity Measurement of Particles Using Interferometric Laser Imaging

    Science.gov (United States)

    Gunawardana, R.; Zarzecki, M.; Diez, F. J.

    2008-11-01

    Global Sizing Velocimetry (GSV) is a recently developed technique for characterizing the particle size distribution and flow velocity in a plane and in this research we extend this measurement to a volume through a laser scanning system. In GSV, a LASER sheet is used to illuminate translucent particles in a spray or flow field and the camera image is de-focused a known distance to create interference patterns. The diameters of the particles in the flow field are calculated by measuring the inter-fringe spacing in the resulting interferogram. Particle Imaging Velocimetry (PIV) techniques are used to compute velocity by measuring the particle displacement over a known short time interval. Researchers have recently begun applying GSV techniques to characterize sprays in a plane as it offers a larger area of investigation than other well known techniques such as Phase Doppler Anemometry (PDA). In this paper we extend GSA techniques from the current planar measurements to a volumetric measurement. The approach uses a high speed camera to acquire GSA images by scanning multiple planes in a volume of the flow field within a short period of time and obtain particle size distribution and velocity measurements in the entire volume.

  4. Evaluation of Routine Atmospheric Sounding Measurements Using Unmanned Systems (ERASMUS) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    de Boer, Gijs [Univ. of Colorado, Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences (CIRES); Lawrence, Dale [Univ. of Colorado, Boulder, CO (United States); Palo, Scott [Univ. of Colorado, Boulder, CO (United States); Argrow, Brian [Univ. of Colorado, Boulder, CO (United States); LoDolce, Gabriel [Univ. of Colorado, Boulder, CO (United States); Curry, Nathan [Univ. of Colorado, Boulder, CO (United States); Weibel, Douglas [Univ. of Colorado, Boulder, CO (United States); Finnamore, W [Univ. of Colorado, Boulder, CO (United States); D' Amore, P [Univ. of Colorado, Boulder, CO (United States); Borenstein, Steven [Univ. of Colorado, Boulder, CO (United States); Nichols, Tevis [Univ. of Colorado, Boulder, CO (United States); Elston, Jack [Blackswift Technologies, Boulder, CO (United States); Ivey, Mark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bendure, Al [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schmid, Beat [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Long, Chuck [National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.; Telg, Hagen [Univ. of Colorado, Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences (CIRES); Gao, Rushan [National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.; Hock, T [National Center for Atmospheric Research, Boulder, CO (United States); Bland, Geoff [National Aeronautics and Space Administration (NASA), Washington, DC (United States)

    2017-03-01

    The Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems (ERASMUS) campaign was proposed with two central goals; to obtain scientifically relevant measurements of quantities related to clouds, aerosols, and radiation, including profiles of temperature, humidity, and aerosol particles, the structure of the arctic atmosphere during transitions between clear and cloudy states, measurements that would allow us to evaluate the performance of retrievals from U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility remote sensors in the Arctic atmosphere, and information on the spatial variability of heat and moisture fluxes from the arctic surface; and to demonstrate unmanned aerial system (UAS) capabilities in obtaining measurements relevant to the ARM and ASR programs, particularly for improving our understanding of Arctic clouds and aerosols.

  5. On the measurement of the neutrino velocity applying the standard time of the Global Positioning System

    International Nuclear Information System (INIS)

    Skeivalas, J; Parseliunas, E

    2013-01-01

    The measurement of the neutrino velocity applying the standard time of the Global Positioning System (GPS) is presented in the paper. The practical data were taken from the OPERA experiment, in which neutrino emission from the CERN LHC accelerator to Gran Sasso detector was investigated. The distance between accelerator and detector is about 730 km. The time interval was measured by benchmark clocks, which were calibrated by the standard GPS time signals received from GPS satellites. The calculation of the accuracy of the GPS time signals with respect to changes of the signals' frequencies due to the Doppler effect is presented. It is shown that a maximum error of about 200 ns could occur when GPS time signals are applied for the calibration of the clocks for the neutrino velocity measurements. (paper)

  6. Velocity and phase distribution measurements in vertical air-water annular flows

    International Nuclear Information System (INIS)

    Vassallo, P.

    1997-07-01

    Annular flow topology for three air-water conditions in a vertical duct is investigated through the use of a traversing double-sensor hot-film anemometry probe and differential pressure measurements. Near wall measurements of mean and fluctuating velocities, as well as local void fraction, are taken in the liquid film, with the highest turbulent fluctuations occurring for the flow condition with the largest pressure drop. A modified law-of-the-wall formulation for wall shear is presented which, using near wall values of mean velocity and kinetic energy, agrees reasonably well with the average stress obtained from direct pressure drop measurements. The linear profile using wall coordinates in the logarithmic layer is preserved in annular flow; however, the slope and intercept of the profile differ from the single-phase values for the annular flow condition which has a thicker, more turbulent, liquid film

  7. Calibration of the charge exchange recombination spectroscopy diagnostic for core poloidal rotation velocity measurements on JET

    International Nuclear Information System (INIS)

    Crombe, K.; Andrew, Y.; Giroud, C.; Hawkes, N.C.; Murari, A.; Valisa, M.; Oost, G. van; Zastrow, K.-D.

    2004-01-01

    This article describes recent improvements in the measurement of C 6+ impurity ion poloidal rotation velocities in the core plasma of JET using charge exchange recombination spectroscopy. Two independent techniques are used to provide an accurate line calibration. The first method uses a Perkin-Elmer type 303-306 samarium hollow cathode discharge lamp, with a Sm I line at 528.291 nm close to the C VI line at 529.1 nm. The second method uses the Be II at 527.06 nm and C III at 530.47 nm in the plasma spectrum as two marker lines on either side of the C VI line. Since the viewing chords have both a toroidal and poloidal component, it is important to determine the contribution of the toroidal rotation velocity component separately. The toroidal rotation velocity in the plasma core is measured with an independent charge exchange recombination spectroscopy diagnostic, looking tangentially at the plasma core. The contribution of this velocity along the lines of sight of the poloidal rotation diagnostic has been determined experimentally in L-mode plasmas keeping the poloidal component constant (K. Crombe et al., Proc. 30th EPS Conference, St. Petersburg, Russia, 7-11 July 2003, p. 1.55). The results from these experiments are compared with calculations of the toroidal contribution that take into account the original design parameters of the diagnostic and magnetic geometry of individual shots

  8. Measurement and Numerical Simulation of Air Velocity in a Tunnel-Ventilated Broiler House

    Directory of Open Access Journals (Sweden)

    Eliseo Bustamante

    2015-02-01

    Full Text Available A building needs to be designed for the whole period of its useful life according to its requirements. However, future climate predictions involve some uncertainty. Thus, several sustainable strategies of adaptation need to be incorporated after the initial design. In this sense, tunnel ventilation in broiler houses provides high air velocity values (2–3 m·s−1 at animal level to diminish their thermal stress and associated mortality. This ventilation system was experimentally incorporated into a Mediterranean climate. The aim was to resolve these thermal problems in hot seasons, as (traditional cross-mechanical ventilation does not provide enough air velocity values. Surprisingly, very little information on tunnel ventilation systems is available, especially in terms of air velocity. Using Computational Fluid Dynamics (CFD and a multi-sensor system, the average results are similar (at animal level: 1.59 ± 0.68 m·s−1 for CFD and 1.55 ± 0.66 m·s−1 for measurements. The ANOVA for validation concluded that the use of CFD or measurements is not significant (p-value = 0.1155. Nevertheless, some problems with air velocity distribution were found and need to be solved. To this end, CFD techniques can help by means of virtual designs and scenarios providing information for the whole indoor space.

  9. Measurement of electroosmotic and electrophoretic velocities using pulsed and sinusoidal electric fields.

    Science.gov (United States)

    Sadek, Samir H; Pimenta, Francisco; Pinho, Fernando T; Alves, Manuel A

    2017-04-01

    In this work, we explore two methods to simultaneously measure the electroosmotic mobility in microchannels and the electrophoretic mobility of micron-sized tracer particles. The first method is based on imposing a pulsed electric field, which allows to isolate electrophoresis and electroosmosis at the startup and shutdown of the pulse, respectively. In the second method, a sinusoidal electric field is generated and the mobilities are found by minimizing the difference between the measured velocity of tracer particles and the velocity computed from an analytical expression. Both methods produced consistent results using polydimethylsiloxane microchannels and polystyrene micro-particles, provided that the temporal resolution of the particle tracking velocimetry technique used to compute the velocity of the tracer particles is fast enough to resolve the diffusion time-scale based on the characteristic channel length scale. Additionally, we present results with the pulse method for viscoelastic fluids, which show a more complex transient response with significant velocity overshoots and undershoots after the start and the end of the applied electric pulse, respectively. © 2016 The Authors. Electrophoresis published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Accuracy limitations for low velocity measurements and draft assessment in rooms

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Popiolek, Zbigniew J.; Silva, M.G.

    2007-01-01

    must be known in order to perform reliable assessment and validation. At present, a low-velocity thermal anemometer (LVTA) with an omnidirectional (spherical) sensor is most often used in practice for measuring air speed due to its low price and easy and convenient operation. The accuracy of the speed......, the definition of realistic requirements in thermal comfort standards as well as validation of CFD predictions is made possible.......The measurement of air temperature, mean air speed, and turbulence intensity is required in order to assess air distribution and draft discomfort in ventilated rooms. The measurements are also used for validation of computational fluid dynamics (CFD) predictions. The uncertainty of the measurements...

  11. [De-noising and measurement of pulse wave velocity of the wavelet].

    Science.gov (United States)

    Liu, Baohua; Zhu, Honglian; Ren, Xiaohua

    2011-02-01

    Pulse wave velocity (PWV) is a vital index of the cardiovascular pathology, so that the accurate measurement of PWV can be of benefit for prevention and treatment of cardiovascular diseases. The noise in the measure system of pulse wave signal, rounding error and selection of the recording site all cause errors in the measure result. In this paper, with wavelet transformation to eliminate the noise and to raise the precision, and with the choice of the point whose slope was maximum as the recording site of the reconstructing pulse wave, the measuring system accuracy was improved.

  12. On the theory of SODAR measurement techniques[SOund Detection And Ranging

    Energy Technology Data Exchange (ETDEWEB)

    Antoniou, I.; Joergensen, H.E. [Risoe National Lab. (Denmark); Ormel, F. [Energy Research Center of the Netherlands (Netherlands); Bradley, S.; Huenerbein, S. von [University of Salford (United Kingdom); Emeis, S. [Forschungszentrum Karlsruhe GmbH (Germany); Warmbier, G. [GWU-Umwelttechnik Gmbh (Germany)

    2003-04-01

    The need for alternative means to measure the wind speed for wind energy purposes has increased with the increase of the size of wind turbines. The cost and the technical difficulties for performing wind speed measurements has also increased with the size of the wind turbines, since it is demanded that the wind speed has to be measured at the rotor centre of the turbine and the size of both the rotor and the hub height have grown following the increase in the size of the wind turbines. The SODAR (SOund Detection And Ranging) is an alternative to the use of cup anemometers and offers the possibility of measuring both the wind speed distribution with height and the wind direction. At the same time the SODAR presents a number of serious drawbacks such as the low number of measurements per time period, the dependence of the ability to measure on the atmospheric conditions and the difficulty of measuring at higher wind speeds due to either background noise or the neutral condition of the atmosphere. Within the WISE project (EU project number NNE5-2001-297), a number of work packages have been defined in order to deal with the SODAR. The present report is the result of the work package 1. Within this package the objective has been to present and achieve the following: 1) An accurate theoretic model that describes all the relevant aspects of the interaction of the sound beam with the atmosphere in the level of detail needed for wind energy applications. 2) Understanding of dependence of SODAR performance on hard- and software configuration. 3) Quantification of principal difference between SODAR wind measurement and wind speed measurements with cup anemometers with regard to power performance measurements.

  13. Luminescent two-color tracer particles for simultaneous velocity and temperature measurements in microfluidics

    International Nuclear Information System (INIS)

    Massing, J; Kähler, C J; Cierpka, C; Kaden, D

    2016-01-01

    The simultaneous and non-intrusive measurement of temperature and velocity fields in flows is of great scientific and technological interest. To sample the velocity and temperature, tracer particle based approaches have been developed, where the velocity is measured using PIV or PTV and the temperature is obtained from the intensity (LIF, thermographic phosphors) or frequency (TLC) of the light emitted or reflected by the tracer particles. In this article, a measurement technique is introduced, that relates the luminescent intensity ratio of individual dual-color luminescent tracer particles to temperature. Different processing algorithms are tested on synthetic particle images and compared with respect to their accuracy in estimating the intensity ratio. Furthermore, polymer particles which are doped with the temperature sensitive dye europium (III) thenoyltrifluoroacetonate (EuTTA) and the nearly temperature insensitive reference dye perylene are characterized as valid tracers. The results show a reduction of the temperature measurement uncertainty of almost 40% (95% confidence interval) compared to previously reported luminescent particle based measurement techniques for microfluidics. (paper)

  14. Measurement of the Velocity and Pressure Drop in a Tubular Type Fuel

    International Nuclear Information System (INIS)

    Jonghark Park; Heetaek Chae; Cheol Park; Heonil Kim

    2006-01-01

    We have developed a tubular type fuel assembly design as one of candidates for fuel to be used in the Advanced HANARO Reactor (AHR). The tubular type fuel has several merits over a rod type fuel with respect to the thermal-hydraulic and structural safety; the larger ratio of surface area to volume makes the surface temperature of a fuel element become lower, and curved plate is stronger against longitudinal bending and vibration. In the other side, a disadvantage is expected such that the flow velocity can be distributed unevenly channel by channel because the flow channels are isolated from each other in a tubular type fuel assembly. In addition to the design development, we also investigated the flow characteristics of the tubular fuel experimentally. To examine the flow velocity distribution and pressure drop, we made an experiment facility and a mockup of the tubular fuel assembly. The fuel assembly consists of 6 concentric fuel tubes so that 7 layers are made between fuel tubes. Since each layer is divided into three sections by stiffeners, 21 isolated flow channels are made in total. We employed pitot-tubes to measure the coolant velocity in each channel. The maximum velocity was measured as large as about 28% of the average velocity. It was observed in the innermost channel contrarily to the expectation from the hydraulic diameter. A change in the total flow rate did not affect the flow distribution. Meanwhile, the pressure drop was measured as about 70% of the drop in the rod type fuel assembly in use in HANARO. (authors)

  15. Acoustical measurements of sound fields between the stage and the orchestra pit inside an historical opera house

    Science.gov (United States)

    Sato, Shin-Ichi; Prodi, Nicola; Sakai, Hiroyuki

    2004-05-01

    To clarify the relationship of the sound fields between the stage and the orchestra pit, we conducted acoustical measurements in a typical historical opera house, the Teatro Comunale of Ferrara, Italy. Orthogonal factors based on the theory of subjective preference and other related factors were analyzed. First, the sound fields for a singer on the stage in relation to the musicians in the pit were analyzed. And then, the sound fields for performers in the pit in relation to the singers on the stage were considered. Because physical factors vary depending on the location of the sound source, performers can move on the stage or in the pit to find the preferred sound field.

  16. Measurements and correlations of turbulent burning velocities over wide ranges of fuels and elevated pressures

    KAUST Repository

    Bradley, Derek; Lawes, Malcolm; Liu, Kexin; Mansour, Morkous S.

    2013-01-01

    The implosion technique has been used to extend measurements of turbulent burning velocities over greater ranges of fuels and pressures. Measurements have been made up to 3.5 MPa and at strain rate Markstein numbers as low as 23. The implosion technique, with spark ignition at two opposite wall positions within a fan-stirred spherical bomb is capable of measuring turbulent burning velocities, at higher pressures than is possible with central ignition. Pressure records and schlieren high speed photography define the rate of burning and the smoothed area of the flame front. The first aim of the study was to extend the previous measurements with ethanol and propane-air, with further measurements over wider ranges of fuels and equivalence ratios with mixtures of hydrogen, methane, 10% hydrogen-90% methane, toluene, and i-octane, with air. The second aim was to study further the low turbulence regime in which turbulent burning co-exists with laminar flame instabilities. Correlations are presented of turbulent burning velocity normalised by the effective rms turbulent velocity acting on the flame front, ut=u0k , with the Karlovitz stretch factor, K, for different strain rate Markstein numbers, a decrease in which increases ut=u0k . Experimental correlations are presented for the present measurements, combined with previous ones. Different burning regimes are also identified, extending from that of mixed turbulence/laminar instability at low values of K to that at high values of K, in which ut=u0k is gradually reduced due to increasing localised flame extinctions. © 2012 The Combustion Institute.

  17. Comparison of index velocity measurements made with a horizontal acoustic Doppler current profiler

    Science.gov (United States)

    Jackson, P. Ryan; Johnson, Kevin K.; Duncker, James J.

    2012-01-01

    The State of Illinois' annual withdrawal from Lake Michigan is limited by a U.S. Supreme Court decree, and the U.S. Geological Survey (USGS) is responsible for monitoring flows in the Chicago Sanitary and Ship Canal (CSSC) near Lemont, Illinois as a part of the Lake Michigan Diversion Accounting overseen by the U.S. Army Corps of Engineers, Chicago District. Every 5 years, a technical review committee consisting of practicing engineers and academics is convened to review the U.S. Geological Survey's streamgage practices in the CSSC near Lemont, Illinois. The sixth technical review committee raised a number of questions concerning the flows and streamgage practices in the CSSC near Lemont and this report provides answers to many of those questions. In addition, it is the purpose of this report to examine the index velocity meters in use at Lemont and determine whether the acoustic velocity meter (AVM), which is now the primary index velocity meter, can be replaced by the horizontal acoustic Doppler current profiler (H-ADCP), which is currently the backup meter. Application of the AVM and H-ADCP to index velocity measurements in the CSSC near Lemont, Illinois, has produced good ratings to date. The site is well suited to index velocity measurements in spite of the large range of velocities and highly unsteady flows at the site. Flow variability arises from a range of sources: operation of the waterway through control structures, lockage-generated disturbances, commercial and recreational traffic, industrial withdrawals and discharges, natural inflows, seiches, and storm events. The influences of these factors on the index velocity measurements at Lemont is examined in detail in this report. Results of detailed data comparisons and flow analyses show that use of bank-mounted instrumentation such as the AVM and H-ADCP appears to be the best option for index velocity measurement in the CSSC near Lemont. Comparison of the rating curves for the AVM and H-ADCP demonstrates

  18. Radar speed gun true velocity measurements of sports-balls in flight: application to tennis

    International Nuclear Information System (INIS)

    Robinson, Garry; Robinson, Ian

    2016-01-01

    Spectators of ball-games often seem to be fascinated by the speed of delivery of the ball. They appear to be less interested in or even oblivious to the mechanism and accuracy of the measurement or where in the flight path of the ball the measurement is actually made. Radar speed guns using the Doppler effect are often employed for such speed measurements. It is well known that such guns virtually always measure the line-of-sight or radial velocity of the ball and as such will return a reading less than or equal to the true speed of the ball. In this paper, using only basic physics principles we investigate such measurements, in particular those associated with the service stroke in tennis. For the service trajectories employed here, a single radar gun located in line with the centre-line of the court in fact under-estimates the speed of a wide serve by about 3.4% at the point of delivery, and by about 14.3% on impact with the court. However, we demonstrate that both the magnitude and direction of the true velocity of the ball throughout its entire flight path may be obtained, at least in principle, by the use of four suitably placed radar speed guns. These four guns must be able to measure the ‘range’ to the ball, enabling its position in flight to be determined, and three of them must be able to measure the radial velocity of the ball. Restrictions on the locations of the speed guns are discussed. Such restrictions are quite liberal, although there are certain configurations of the radar gun positions which cannot be used. Importantly, with the one proviso that no speed gun can be directly in the path of the ball (not only for the obvious reasons), we find that if the speed of the ball can be determined for one point in the trajectory, it can also be determined for all points. The accuracy of the range and radial velocity measurements required to give meaningful results for the true velocity are also briefly discussed. It is found that the accuracy required

  19. Ultrasound Characterization of Microbead and Cell Suspensions by Speed of Sound Measurements of Neutrally Buoyant Samples

    DEFF Research Database (Denmark)

    Cushing, Kevin W.; Garofalo, Fabio; Magnusson, Cecilia

    2017-01-01

    . The density of the microparticles is determined by using a neutrally buoyant selection process that involves centrifuging of microparticles suspended in different density solutions, CsCl for microbeads and Percoll for cells. The speed of sound at 3 MHz in the neutrally buoyant suspensions is measured...... and fixed cells, such as red blood cells, white blood cells, DU-145 prostate cancer cells, MCF-7 breast cancer cells, and LU-HNSCC-25 head and-neck squamous carcinoma cells in phosphate buffered saline. The results show agreement with published data obtained by other methods....

  20. Optimizing measurements of cluster velocities and temperatures for CCAT-prime and future surveys

    Science.gov (United States)

    Mittal, Avirukt; de Bernardis, Francesco; Niemack, Michael D.

    2018-02-01

    Galaxy cluster velocity correlations and mass distributions are sensitive probes of cosmology and the growth of structure. Upcoming microwave surveys will enable extraction of velocities and temperatures from many individual clusters for the first time. We forecast constraints on peculiar velocities, electron temperatures, and optical depths of galaxy clusters obtainable with upcoming multi-frequency measurements of the kinematic, thermal, and relativistic Sunyaev-Zeldovich effects. The forecasted constraints are compared for different measurement configurations with frequency bands between 90 GHz and 1 THz, and for different survey strategies for the 6-meter CCAT-prime telescope. We study methods for improving cluster constraints by removing emission from dusty star forming galaxies, and by using X-ray temperature priors from eROSITA. Cluster constraints are forecast for several model cluster masses. A sensitivity optimization for seven frequency bands is presented for a CCAT-prime first light instrument and a next generation instrument that takes advantage of the large optical throughput of CCAT-prime. We find that CCAT-prime observations are expected to enable measurement and separation of the SZ effects to characterize the velocity, temperature, and optical depth of individual massive clusters (~1015 Msolar). Submillimeter measurements are shown to play an important role in separating these components from dusty galaxy contamination. Using a modular instrument configuration with similar optical throughput for each detector array, we develop a rule of thumb for the number of detector arrays desired at each frequency to optimize extraction of these signals. Our results are relevant for a future "Stage IV" cosmic microwave background survey, which could enable galaxy cluster measurements over a larger range of masses and redshifts than will be accessible by other experiments.

  1. Double-energy double-velocity measurement system for fission fragments and its application

    International Nuclear Information System (INIS)

    Kanno, Ikuo

    1987-10-01

    A new system of double-energy double-velocity (DEDV) measurement for fission fragments has been developed. In this system, the energies of fission fragments are measured by silicon surface barrier detectors (SSB) and the velocities by the time-of-flight (TOF) method utilizing thin film detectors (TFD) as start detectors and SSBs as stop detectors of TOF. Theoretical and experimental studies on TFDs and SSBs have been performed before the construction of the DEDV measurement system. The TFD consists of a thin plastic scintillator film and light guide. The author proposes a new model of the luminescence production in a scintillator film. This model takes into account the thickness of the scintillator film and uses only one parameter. The calculated TFD response to charged particles shows good agreement with other experiments. The dependence of the TFD response to the thickness of the scintillator film has been studied experimentally and analyzed by the luminescence production model. The results of this analysis shows the validity of the luminescence production model. The time resolution of the DEDV measurement system using TFDs and SSBs was 133 ps. As an application of this system, the DEDV measurement for the thermal neutron-induced fission of 233 U has been carried out at the super mirror neutron guide tube facility of Kyoto University Reactor (KUR). The energy and velocity of each fission fragment have been stored on magnetic disk event by event in a list mode. The analyzed results of masses, energies and velocities of light and heavy fragments agree well with other authors' works. The value of the total neutron emission number is 2.53 and shows good agreement within experimental error, with the JENDL-2 value, 2.49. The light fragment shows a slightly greater number of neutrons emitted than the other works. This suggests the possibility of larger deformation of light fragments at the scission point. (author)

  2. New developments in velocity profile measurement and pipe wall wear monitoring for hydrotransport lines

    Energy Technology Data Exchange (ETDEWEB)

    O' Keefe, C.; Maron, R.J. [CiDRA Minerals Processing Inc., Wallingford, CT (United States); Fernald, M.; Bailey, T. [CiDRA Corporate Services, Wallingford, CT (United States); Van der Spek, A. [ZDOOR, Rotterdam (Netherlands)

    2009-07-01

    Sonar array flow measurement technology was initially developed a decade ago with the goal of non-invasively measuring multi-phase flows in the petroleum industry. The same technology was later adapted to the mineral processing industry where it has been rapidly adopted. The specific sensor technology, based on piezoelectric film sensors, provides unique measurement capabilities, including the ability to non-invasively measure localized strains in the walls of pipes. Combined with sonar array processing algorithms, an axial array of such sensors can measure flow velocities within a pipe. The sensors are useful for monitoring and managing slurry flow in horizontal pipes since they provide real-time velocity profiles measurement. The information is useful in determining the approach and onset of solid deposition on the bottom of the pipe. The sensors also provide a non-invasive measurement of pipe wear on slurry lines. Such measurements are currently made by hand-held portable ultrasonic thickness gages. The shortfalls associated with this manual method are overcome with a set of permanently or semi-permanently installed transducers clamped onto the outside of the pipe, where sensors measure the thickness of the pipe. This system and approach results in better repeatability and accuracy compared to manual methods. It also decreases inspection labor costs and pipe access requirements. It was concluded that the potential impact on personnel safety and environmental savings will be significant. 3 refs., 20 figs.

  3. Measurement of energetic radiation caused by thunderstorm activities by a sounding balloon and ground observation

    Science.gov (United States)

    Torii, T.

    2015-12-01

    Energetic radiation caused by thunderstorm activity is observed at various places, such as the ground, high mountain areas, and artificial satellites. In order to investigate the radiation source and its energy distribution, we measured energetic radiation by a sounding balloon, and the ground observation. On the measurement inside/above the thundercloud, we conducted a sounding observation using a radiosonde mounted two GM tubes (for gamma-rays, and for beta/gamma-rays), in addition to meteorological instruments. The balloon passed through a region of strong echoes in a thundercloud shown by radar image, at which time an increase in counting rate of the GM tube about 2 orders of magnitude occurred at the altitude from 5 km to 7.5 km. Furthermore, the counting rate of two GM tubes indicated the tendency different depending on movement of a balloon. This result suggests that the ratio for the gamma-rays (energetic photons) of the beta-rays (energetic electrons) varies according to the place in the thundercloud. Furthermore, we carried out a ground observation of the energetic gamma rays during winter thunderstorm at a coastal area facing the Sea of Japan. Two types of the energetic radiation have been observed at this time. We report the outline of these measurements and analysis in the session of the AGU meeting.

  4. Is the Speech Transmission Index (STI) a robust measure of sound system speech intelligibility performance?

    Science.gov (United States)

    Mapp, Peter

    2002-11-01

    Although RaSTI is a good indicator of the speech intelligibility capability of auditoria and similar spaces, during the past 2-3 years it has been shown that RaSTI is not a robust predictor of sound system intelligibility performance. Instead, it is now recommended, within both national and international codes and standards, that full STI measurement and analysis be employed. However, new research is reported, that indicates that STI is not as flawless, nor robust as many believe. The paper highlights a number of potential error mechanisms. It is shown that the measurement technique and signal excitation stimulus can have a significant effect on the overall result and accuracy, particularly where DSP-based equipment is employed. It is also shown that in its current state of development, STI is not capable of appropriately accounting for a number of fundamental speech and system attributes, including typical sound system frequency response variations and anomalies. This is particularly shown to be the case when a system is operating under reverberant conditions. Comparisons between actual system measurements and corresponding word score data are reported where errors of up to 50 implications for VA and PA system performance verification will be discussed.

  5. Size, velocity, and concentration in suspension measurements of spherical droplets and cylindrical jets.

    Science.gov (United States)

    Onofri, F; Bergougnoux, L; Firpo, J L; Misguich-Ripault, J

    1999-07-20

    The principle of an optical technique for simultaneous velocity, size, and concentration in suspension measurements of spherical droplets and cylindrical jets is proposed. This technique is based on phase Doppler anemometry working in the dual burst technique configuration. The particle size and velocity are deduced from the reflected signal phase and frequency, whereas the amplitude ratio between the refracted and the reflected signals is used for measuring the concentration of small scatterers inside the particles. Numerical simulations, based on geometrical optics and a Monte Carlo model, and an experimental validation test on cylindrical jets made of various suspensions, are used to validate the principle of the proposed technique. It is believed that this new technique could be useful in investigating processes in which liquid suspensions are sprayed for surface coating, drying, or combustion applications.

  6. Application of advanced one sided stress wave velocity measurement in concrete

    International Nuclear Information System (INIS)

    Lee, Joon Hyun; Song, Won Joon; Popovices, J. S.; Achenbach, J. D.

    1997-01-01

    It is of interest to reliably measure the velocity of stress waves in concrete. At present, reliable measurement is not possible for dispersive and attenuating materials such as concrete when access to only one surface of the structure is available, such as in the case of pavement structures. In this paper, a new method for one-sided stress wave velocity determination in concrete is applied to investigate the effects of composition, age and moisture content. This method uses a controlled impact as a stress wave source and two sensitive receivers mounted on the same surface as the impact sites. The novel aspect of the technique is the data collection system which automatically determines the arrival of the generated longitudinal and surface wave arrivals. A conventional ultrasonic through transmission method is used to compare with the results determined by the one-sided method.

  7. EISCAT measurements of solar wind velocity and the associated level of interplanetary scintillation

    Directory of Open Access Journals (Sweden)

    R. A. Fallows

    2002-09-01

    Full Text Available A relative scintillation index can be derived from EISCAT observations of Interplanetary Scintillation (IPS usually used to study the solar wind velocity. This provides an ideal opportunity to compare reliable measurements of the solar wind velocity derived for a number of points along the line-of-sight with measurements of the overall level of scintillation. By selecting those occasions where either slow- or fast-stream scattering was dominant, it is shown that at distances from the Sun greater than 30 RS , in both cases the scintillation index fell with increasing distance as a simple power law, typically as R-1.7. The level of scintillation for slow-stream scattering is found to be 2.3 times the level for fast-stream scattering.Key words. Interplanetary physics (solar wind plasma

  8. Measurement of fluid velocity development behind a circular cylinder using particle image velocimetry (PIV)

    International Nuclear Information System (INIS)

    Goharzadeh, Afshin; Molki, Arman

    2015-01-01

    In this paper we present a non-intrusive experimental approach for obtaining a two-dimensional velocity distribution around a 22 mm diameter circular cylinder mounted in a water tunnel. Measurements were performed for a constant Reynolds number of 7670 using a commercial standard particle image velocimetry (PIV) system. Different flow patterns generated behind the circular cylinder are discussed. Both instantaneous and time-averaged velocity distributions with corresponding streamlines are obtained. Key concepts in fluid mechanics, such as contra-rotating vortices, von Kármán vortex street, and laminar-turbulent flow, are discussed. In addition, brief historical information pertaining to the development of flow measurement techniques—in particular, PIV—is described. (paper)

  9. Flow visualization and velocity measurement in a small-scale open channel using an electron microscope

    International Nuclear Information System (INIS)

    Yasuda, K; Sogo, M; Iwamoto, Y

    2013-01-01

    The present note describes a method for use in conjunction with a scanning electron microscope (SEM) that has been developed to visualize a liquid flow under a high-level vacuum and to measure a velocity field in a small-scale flow through an open channel. In general, liquid cannot be observed via a SEM, because liquid evaporates under the high-vacuum environment of the SEM. As such, ionic liquid and room temperature molten salt having a vapor pressure of nearly zero is used in the present study. We use ionic liquid containing Au-coated tracer particles to visualize a small-scale flow under a SEM. Furthermore, the velocity distribution in the open channel is obtained by particle tracking velocimetry measurement and a parabolic profile is confirmed. (technical design note)

  10. Measurements of low density, high velocity flow by electron beam fluorescence technique

    International Nuclear Information System (INIS)

    Soga, Takeo; Takanishi, Masaya; Yasuhara, Michiru

    1981-01-01

    A low density chamber with an electron gun system was made for the measurements of low density, high velocity (high Mach number) flow. This apparatus is a continuous running facility. The number density and the rotational temperature in the underexpanding free jet of nitrogen were measured along the axis of the jet by the electron beam fluorescence technique. The measurements were carried out from the vicinity of the exit of the jet to far downstream of the first Mach disk. Rotational nonequilibrium phenomena were observed in the hypersonic flow field as well as in the shock wave (Mach disk). (author)

  11. Estimating random transverse velocities in the fast solar wind from EISCAT Interplanetary Scintillation measurements

    Directory of Open Access Journals (Sweden)

    A. Canals

    2002-09-01

    Full Text Available Interplanetary scintillation measurements can yield estimates of a large number of solar wind parameters, including bulk flow speed, variation in bulk velocity along the observing path through the solar wind and random variation in transverse velocity. This last parameter is of particular interest, as it can indicate the flux of low-frequency Alfvén waves, and the dissipation of these waves has been proposed as an acceleration mechanism for the fast solar wind. Analysis of IPS data is, however, a significantly unresolved problem and a variety of a priori assumptions must be made in interpreting the data. Furthermore, the results may be affected by the physical structure of the radio source and by variations in the solar wind along the scintillation ray path. We have used observations of simple point-like radio sources made with EISCAT between 1994 and 1998 to obtain estimates of random transverse velocity in the fast solar wind. The results obtained with various a priori assumptions made in the analysis are compared, and we hope thereby to be able to provide some indication of the reliability of our estimates of random transverse velocity and the variation of this parameter with distance from the Sun.Key words. Interplanetary physics (MHD waves and turbulence; solar wind plasma; instruments and techniques

  12. Estimating random transverse velocities in the fast solar wind from EISCAT Interplanetary Scintillation measurements

    Directory of Open Access Journals (Sweden)

    A. Canals

    Full Text Available Interplanetary scintillation measurements can yield estimates of a large number of solar wind parameters, including bulk flow speed, variation in bulk velocity along the observing path through the solar wind and random variation in transverse velocity. This last parameter is of particular interest, as it can indicate the flux of low-frequency Alfvén waves, and the dissipation of these waves has been proposed as an acceleration mechanism for the fast solar wind. Analysis of IPS data is, however, a significantly unresolved problem and a variety of a priori assumptions must be made in interpreting the data. Furthermore, the results may be affected by the physical structure of the radio source and by variations in the solar wind along the scintillation ray path. We have used observations of simple point-like radio sources made with EISCAT between 1994 and 1998 to obtain estimates of random transverse velocity in the fast solar wind. The results obtained with various a priori assumptions made in the analysis are compared, and we hope thereby to be able to provide some indication of the reliability of our estimates of random transverse velocity and the variation of this parameter with distance from the Sun.

    Key words. Interplanetary physics (MHD waves and turbulence; solar wind plasma; instruments and techniques

  13. Standard practice for measuring the ultrasonic velocity in polyethylene tank walls using lateral longitudinal (LCR) waves

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This practice covers a procedure for measuring the ultrasonic velocities in the outer wall of polyethylene storage tanks. An angle beam lateral longitudinal (LCR) wave is excited with wedges along a circumferential chord of the tank wall. A digital ultrasonic flaw detector is used with sending-receiving search units in through transmission mode. The observed velocity is temperature corrected and compared to the expected velocity for a new, unexposed sample of material which is the same as the material being evaluated. The difference between the observed and temperature corrected velocities determines the degree of UV exposure of the tank. 1.2 The practice is intended for application to the outer surfaces of the wall of polyethylene tanks. Degradation typically occurs in an outer layer approximately 3.2-mm (0.125-in.) thick. Since the technique does not interrogate the inside wall of the tank, wall thickness is not a consideration other than to be aware of possible guided (Lamb) wave effects or reflection...

  14. Development of two-dimensional velocity field measurement using particle tracking velocimetry on neutron radiography

    International Nuclear Information System (INIS)

    Saito, Y.; Mishima, K.; Suzuki, T.; Matsubayashi, M.

    2003-01-01

    The structures of liquid metal two-phase flow are investigated for analyzing the core meltdown accident of fast reactor. The experiments of high-density ratio two-phase flow for lead-bismuth molten metal and nitrogen gases are conducted to understand in detail. The liquid phase velocity distributions of lead-bismuth molten metal are measured by neutron radiography using Au-Cd tracer particles. The liquid phase velocity distributions are obtained usually by using particle image velocimetry (PIV) on the neutron radiography. The PIV, however is difficult to get the velocity vector distribution quantitatively. An image of neutron radiography is divided into two images of the bubbles and the tracer particles each in particle tracking velocimetry (PTV), which distinguishes tracer contents in the bubble from them in the liquid phase. The locations of tracer particles in the liquid phase are possible to determine by particle mask correlation method, in which the bubble images are separated from the tracer images by Σ-scaling method. The particle tracking velocimetry give a full detail of the velocity vector distributions of the liquid phase in two-phase flow, in comparison with the PIV method. (M. Suetake)

  15. Measurements of gas velocity in supersonic flow using a laser beam

    International Nuclear Information System (INIS)

    Airoldi, V.J.T.; Santos, R. dos

    1982-01-01

    A study of measurements of supersonic velocities in a wind tunnel using a laser beam was performed. Techniques using lasers are most suitable because they do not disturb the gas flow. This work presents the technique entitled as fringe technique. It works using interference patterns due to two perpendicular laser beams crossing the sample (i.e. the gas flow). Experimental results are compared with other usual techniques. (R.S.)

  16. On the Disambiguation of Passively Measured In-home Gait Velocities from Multi-person Smart Homes.

    Science.gov (United States)

    Austin, Daniel; Hayes, Tamara L; Kaye, Jeffrey; Mattek, Nora; Pavel, Misha

    2011-01-01

    In-home monitoring of gait velocity with passive PIR sensors in a smart home has been shown to be an effective method of continuously and unobtrusively measuring this important predictor of cognitive function and mobility. However, passive measurements of velocity are nonspecific with regard to who generated each measurement or walking event. As a result, this method is not suitable for multi-person homes without additional information to aid in the disambiguation of gait velocities. In this paper we propose a method based on Gaussian mixture models (GMMs) combined with infrequent clinical assessments of gait velocity to model in-home walking speeds of two or more residents. Modeling the gait parameters directly allows us to avoid the more difficult problem of assigning each measured velocity individually to the correct resident. We show that if the clinically measured gait velocities of residents are separated by at least 15 cm/s a GMM can be accurately fit to the in-home gait velocity data. We demonstrate the accuracy of this method by showing that the correlation between the means of the GMMs and the clinically measured gait velocities is 0.877 (p value < 0.0001) with bootstrapped 95% confidence intervals of (0.79, 0.94) for 54 measurements of 20 subjects living in multi-person homes. Example applications of using this method to track in-home mean velocities over time are also given.

  17. Local liquid velocity measurement of Trickle Bed Reactor using Digital Industrial X-ray Radiography

    Science.gov (United States)

    Mohd Salleh, Khairul Anuar

    Trickle Bed Reactors (TBRs) are fixed beds of particles in which both liquid and gas flow concurrently downward. They are widely used to produce not only fuels but also lubrication products. The measurement and the knowledge of local liquid velocities (VLL) in TBRs is less which is essential for advancing the understanding of its hydrodynamics and for validation computational fluid dynamics (CFD). Therefore, this work focused on developing a new, non-invasive, statistically reliable technique that can be used to measure local liquid velocity (VLL) in two-dimensions (2-D). This is performed by combining Digital Industrial X-ray Radiography (DIR) and Particle Tracking Velocimetry (PTV) techniques. This work also make possible the development of three-dimensional (3-D) VLL measurements that can be taken in TBRs. Measurements taken through both the combined and the novel technique, once validated, were found to be comparable to another technique (a two-point fiber optical probe) currently being developed at Missouri University of Science and Technology. The results from this study indicate that, for a gas-liquid-solid type bed, the measured VLL can have a maximum range that is between 35 and 51 times that of its superficial liquid velocity (VSL). Without the existence of gas, the measured VLL can have a maximum range that is between 4 and 4.7 times that of its VSL. At a higher V SL, the particle tracer was greatly distributed and became carried away by a high liquid flow rate. Neither the variance nor the range of measured VLL varied for any of the replications, confirming the reproducibility of the experimental measurements used, regardless of the VSL . The liquid's movement inside the pore was consistent with findings from previous studies that used various techniques.

  18. Velocity profile measurement of lead-lithium flows by high-temperature ultrasonic doppler velocimetry

    International Nuclear Information System (INIS)

    Ueki, Y.; Kunugi, T.; Hirabayashi, Masaru; Nagai, Keiichi; Saito, Junichi; Ara, Kuniaki; Morley, N.B.

    2014-01-01

    This paper describes a high-temperature ultrasonic Doppler Velocimetry (HT-UDV) technique that has been successfully applied to measure velocity profiles of the lead-lithium eutectic alloy (PbLi) flows. The impact of tracer particles is investigated to determine requirements for HT-UDV measurement of PbLi flows. The HT-UDV system is tested on a PbLi flow driven by a rotating-disk in an inert atmosphere. We find that a sufficient amount of particles contained in the molten PbLi are required to successfully measure PbLi velocity profiles by HT-UDV. An X-ray diffraction analysis is performed to identify those particles in PbLi, and indicates that those particles were made of the lead mono-oxide (PbO). Since the specific densities of PbLi and PbO are close to each other, the PbO particles are expected to be well-dispersed in the bulk of molten PbLi. We conclude that the excellent dispersion of PbO particles enables in HT-UDV to obtain reliable velocity profiles for operation times of around 12 hours. (author)

  19. Instantaneous ballistic velocity of suspended Brownian nanocrystals measured by upconversion nanothermometry

    Science.gov (United States)

    Brites, Carlos D. S.; Xie, Xiaoji; Debasu, Mengistie L.; Qin, Xian; Chen, Runfeng; Huang, Wei; Rocha, João; Liu, Xiaogang; Carlos, Luís D.

    2016-10-01

    Brownian motion is one of the most fascinating phenomena in nature. Its conceptual implications have a profound impact in almost every field of science and even economics, from dissipative processes in thermodynamic systems, gene therapy in biomedical research, artificial motors and galaxy formation to the behaviour of stock prices. However, despite extensive experimental investigations, the basic microscopic knowledge of prototypical systems such as colloidal particles in a fluid is still far from being complete. This is particularly the case for the measurement of the particles' instantaneous velocities, elusive due to the rapid random movements on extremely short timescales. Here, we report the measurement of the instantaneous ballistic velocity of Brownian nanocrystals suspended in both aqueous and organic solvents. To achieve this, we develop a technique based on upconversion nanothermometry. We find that the population of excited electronic states in NaYF4:Yb/Er nanocrystals at thermal equilibrium can be used for temperature mapping of the nanofluid with great thermal sensitivity (1.15% K-1 at 296 K) and a high spatial resolution (<1 μm). A distinct correlation between the heat flux in the nanofluid and the temporal evolution of Er3+ emission allows us to measure the instantaneous velocity of nanocrystals with different sizes and shapes.

  20. The velocity measurement by LDV at the simulated plate fuel assembly

    International Nuclear Information System (INIS)

    Tae Sung Ha

    2001-01-01

    For a more accurate safety analysis for McMaster Nuclear Reactor (MNR), local velocity measurements in a mock-up of the 18-plate fuel assembly are conducted over the range of M=2.0kg/s to 5.0kg/s (u=0.59m/s to 1.48m/s). To enable the measurement of the mass flow distribution through the channels by Laser Doppler Velocimeter(LDV), the curved fuel plate assembly is modified to flat fuel plates. The experimental result shows that the velocity profile is fairly symmetric for the 1st channel to the 17th subchannel at its center. The velocity in the peripheral area is slightly decreased while that directly above the circular pipe is correspondingly increased due to the effect of blockage by the exit endfitting. The mass flow rate fraction is fairly well distributed from the 1st to the 9th channels; at the outmost channels (1st and 3rd subchannels) the flow is approximately 95-97% of the average channel flow and at the central channels (4th and 8th subchannels) the flow is about 102-105% of the average channel mass flow rate. It is shown that the measured mass flow distribution is consistent with the results of the numerical calculation except 1st and 17th channels. (author)

  1. Evaluation and accuracy of the local velocity data measurements in an agitated vessel

    Directory of Open Access Journals (Sweden)

    Kysela Bohuš

    2014-03-01

    Full Text Available Velocity measurements of the flow field in an agitated vessel are necessary for the improvement and better understanding of the mixing processes. The obtained results are used for the calculations of the impeller pumping capacity, comparison of the power consumption etc. We performed various measurements of the local velocities in an agitated vessel final results of which should be processed for several purposes so it was necessary to make an analysis of the obtained data suitability and their quality. Analysed velocity data were obtained from the LDA (Laser Doppler Anemometry and PIV (Particle Image Velocimetry measurements performed on a standard equipment where the flat bottomed vessel with four baffles was agitated by the six-blade Rushton turbine. The results from both used methods were compared. The frequency analyses were examined as well as the dependency of the data rates, time series lengths etc. The demands for the data processed in the form of the ensemble-averaged results were also established.

  2. Procedures, analysis, and comparison of groundwater velocity measurement methods for unconfined aquifers

    International Nuclear Information System (INIS)

    Kearl, P.M.; Dexter, J.J.; Price, J.E.

    1988-09-01

    Six methods for determining the average linear velocity of ground- water were tested at two separate field sites. The methods tested include bail tests, pumping tests, wave propagation, tracer tests, Geoflo Meter/reg sign/, and borehole dilution. This report presents procedures for performing field tests and compares the results of each method on the basis of application, cost, and accuracy. Comparisons of methods to determine the ground-water velocity at two field sites show certain methods yield similar results while other methods measure significantly different values. The literature clearly supports the reliability of pumping tests for determining hydraulic conductivity. Results of this investigation support this finding. Pumping tests, however, are limited because they measure an average hydraulic conductivity which is only representative of the aquifer within the radius of influence. Bail tests are easy and inexpensive to perform. If the tests are conducted on the majority of wells at a hazardous waste site, then the heterogeneity of the site aquifer can be assessed. However, comparisons of bail-test results with pumping-test and tracer-test results indicate that the accuracy of the method is questionable. Consequently, the principal recommendation of this investigation, based on cost and reliability of the ground-water velocity measurement methods, is that bail tests should be performed on all or a majority of monitoring wells at a site to determine the ''relative'' hydraulic conductivities

  3. Sound and sound sources

    DEFF Research Database (Denmark)

    Larsen, Ole Næsbye; Wahlberg, Magnus

    2017-01-01

    There is no difference in principle between the infrasonic and ultrasonic sounds, which are inaudible to humans (or other animals) and the sounds that we can hear. In all cases, sound is a wave of pressure and particle oscillations propagating through an elastic medium, such as air. This chapter...... is about the physical laws that govern how animals produce sound signals and how physical principles determine the signals’ frequency content and sound level, the nature of the sound field (sound pressure versus particle vibrations) as well as directional properties of the emitted signal. Many...... of these properties are dictated by simple physical relationships between the size of the sound emitter and the wavelength of emitted sound. The wavelengths of the signals need to be sufficiently short in relation to the size of the emitter to allow for the efficient production of propagating sound pressure waves...

  4. Integrating Sound Scattering Measurements in the Design of Complex Architectural Surfaces

    DEFF Research Database (Denmark)

    Peters, Brady

    2010-01-01

    Digital tools present the opportunity for incorporating performance analysis into the architectural design process. Acoustic performance is an important criterion for architectural design. There is much known about sound absorption but little about sound scattering, even though scattering is reco...

  5. Use of O2 airglow for calibrating direct atomic oxygen measurements from sounding rockets

    Directory of Open Access Journals (Sweden)

    G. Witt

    2009-12-01

    Full Text Available Accurate knowledge about the distribution of atomic oxygen is crucial for many studies of the mesosphere and lower thermosphere. Direct measurements of atomic oxygen by the resonance fluorescence technique at 130 nm have been made from many sounding rocket payloads in the past. This measurement technique yields atomic oxygen profiles with good sensitivity and altitude resolution. However, accuracy is a problem as calibration and aerodynamics make the quantitative analysis challenging. Most often, accuracies better than a factor 2 are not to be expected from direct atomic oxygen measurements. As an example, we present results from the NLTE (Non Local Thermodynamic Equilibrium sounding rocket campaign at Esrange, Sweden, in 1998, with simultaneous O2 airglow and O resonance fluorescence measurements. O number densities are found to be consistent with the nightglow analysis, but only within the uncertainty limits of the resonance fluorescence technique. Based on these results, we here describe how better atomic oxygen number densities can be obtained by calibrating direct techniques with complementary airglow photometer measurements and detailed aerodynamic analysis. Night-time direct O measurements can be complemented by photometric detection of the O2 (b1∑g+−X3∑g- Atmospheric Band at 762 nm, while during daytime the O2 (a1Δg−X3∑g- Infrared Atmospheric Band at 1.27 μm can be used. The combination of a photometer and a rather simple resonance fluorescence probe can provide atomic oxygen profiles with both good accuracy and good height resolution.

  6. Measurement on the effect of sound wave in upper plenum of boiling water reactor

    International Nuclear Information System (INIS)

    Kumagai, Kosuke; Someya, Satoshi; Okamoto, Koji

    2009-01-01

    In recent years, the power uprate of Boiling Water Reactors have been conducted at several existing power plants as a way to improve plant economy. In one of the power uprated plants (117.8% uprates) in the United States, the steam dryer breakages due to fatigue fracture occurred. It is conceivable that the increased steam flow passing through the branches caused a self-induced vibration with the propagation of sound wave into the steam-dome. The resonance among the structure, flow and the pressure fluctuation resulted in the breakages. To understand the basic mechanism of the resonance, previous researches were done by a point measurement of the pressure and by a phase averaged measurement of the flow, while it was difficult to detect the interaction among them by the conventional method. In this study, Dynamic Particle Image Velocimetry (PIV) System was applied to investigate the effect of sound on natural convection and forced convection. Especially, when the phases of acoustic sources were different, various acoustic wave effects were checked. (author)

  7. Measurement of acoustic characteristics of Japanese Buddhist temples in relation to sound source location and direction.

    Science.gov (United States)

    Soeta, Yoshiharu; Shimokura, Ryota; Kim, Yong Hee; Ohsawa, Tomohiro; Ito, Ken

    2013-05-01

    Although temples are important buildings in the Buddhist community, the acoustic quality has not been examined in detail. Buddhist monks change the location and direction according to the ceremony, and associated acoustical changes have not yet been examined scientifically. To discuss the desired acoustics of temples, it is necessary to know the acoustic characteristics appropriate for each phase of a ceremony. In this study, acoustic measurements were taken at various source locations and directions in Japanese temples. A directional loudspeaker was used as the source to provide vocal acoustic fields, and impulse responses were measured and analyzed. The speech transmission index was higher and the interaural cross-correlation coefficient was lower for the sound source directed toward the side wall than that directed toward the altar. This suggests that the change in direction improves speech intelligibility, and the asymmetric property of direct sound and complex reflections from the altar and side wall increases the apparent source width. The large and coupled-like structure of the altar of a Buddhist temple may have reinforced the reverberation components and the table in the altar, which is called the "syumidan," may have decreased binaural coherence.

  8. Velocity measurements in the near field of a diesel fuel injector by ultrafast imagery

    Science.gov (United States)

    Sedarsky, David; Idlahcen, Saïd; Rozé, Claude; Blaisot, Jean-Bernard

    2013-02-01

    This paper examines the velocity profile of fuel issuing from a high-pressure single-orifice diesel injector. Velocities of liquid structures were determined from time-resolved ultrafast shadow images, formed by an amplified two-pulse laser source coupled to a double-frame camera. A statistical analysis of the data over many injection events was undertaken to map velocities related to spray formation near the nozzle outlet as a function of time after start of injection. These results reveal a strong asymmetry in the liquid profile of the test injector, with distinct fast and slow regions on opposite sides of the orifice. Differences of ˜100 m/s can be observed between the `fast' and `slow' sides of the jet, resulting in different atomization conditions across the spray. On average, droplets are dispersed at a greater distance from the nozzle on the `fast' side of the flow, and distinct macrostructure can be observed under the asymmetric velocity conditions. The changes in structural velocity and atomization behavior resemble flow structures which are often observed in the presence of string cavitation produced under controlled conditions in scaled, transparent test nozzles. These observations suggest that widely used common-rail supply configurations and modern injectors can potentially generate asymmetric interior flows which strongly influence diesel spray morphology. The velocimetry measurements presented in this work represent an effective and relatively straightforward approach to identify deviant flow behavior in real diesel sprays, providing new spatially resolved information on fluid structure and flow characteristics within the shear layers on the jet periphery.

  9. Aerosol deposition velocities on the Pacific and Atlantic oceans calculated from 7Be measurements

    International Nuclear Information System (INIS)

    Young, J.A.; Silker, W.B.

    1979-01-01

    The concentrations of 7 Be were measured in Pacific and Atlantic ocean water for past several years to determine the deposition velocity of aerosol particles on the ocean surface. Beryllium-7 is produced at a relatively constant rate in the atmosphere by spallation reactions of cosmic rays with atmospheric nitrogen and oxygen. Immediately after its formation 7 Be becomes attached to aerosol particles, and therefore can serve as tracers of the subsequent behavior of these particles. Isopleths of 7 Be surface water concentration, 7 Be inventory in the ocean, and deposition velocity have been prepared for the Pacific Ocean from 30 0 S to 60 0 N and for the Atlantic Ocean from 10 0 N to 55 0 N. The concentrations, inventories and deposition velocities tended to be higher in regions where precipitation was high, and generally increased with latitude. The average flux of 7 Be across the ocean surface was calculated to be 0.027 atoms cm -2 sec -1 which is probably not significantly greater than the worldwide average 7 Be flux across land and ocean surfaces of 0.022 atoms cm -2 sec -1 calculated by Lal and Peters. The average deposition velocity was calculated to be 0.80 cm sec -1 . This value may be 10 to 30% too low, since it was calculated using atmospheric 7 Be concentrations which were measured at continental stations. Measurements of atmospheric 7 Be concentrations at ocean stations suggest that the concentrations at the continental stations averaged 10 to 30% higher than the concentrations over the ocean

  10. Aerosol deposition velocities on the Pacific and Atlantic oceans calculated from 7Be measurements

    International Nuclear Information System (INIS)

    Young, J.A.; Silker, W.B.

    1980-01-01

    The concentrations of 7 Be have been measured in Pacific and Atlantic ocean water for the past several years to determine the deposition velocity of aerosol particles on the ocean surface. 7 Be is produced at a relatively constant rate in the atmosphere by spallation reactions of cosmic rays with atmospheric nitrogen and oxygen. Immediately after its formation 7 Be becomes attached to aerosol particles, and therefore can serve as tracers of the subsequent behavior of these particles. Isopleths of 7 Be surface water concentrations, 7 Be inventory in the ocean, and deposition velocity have been prepared for the Pacific Ocean from 30 0 S to 60 0 N and for the Atlantic Ocean from 10 0 N to 55 0 N. The concentrations, inventories and deposition velocities tended to be higher in regions where precipitation was high, and generally increased with latitude. The average flux of 7 Be across the ocean surface was calculated to be 0.027 atoms cm -2 s -1 which is probably not significantly greater than the worldwide average 7 Be flux across land and ocean surfaces of 0.022 atoms cm -2 s -1 calculated by Lal and Peters. The average deposition velocity was calculated to be 0.80 cm s -1 . This value may be 10-50% too low, since it was calculated using atmospheric 7 Be concentrations which were measured at continental stations. Measurements of atmospheric 7 Be concentrations at ocean stations suggest that the concentrations at the continental stations averaged 10-50% higher than the concentrations over the ocean. (orig.)

  11. Measurements of electron drift velocity in isobutane using the pulsed Townsend technique

    International Nuclear Information System (INIS)

    Vivaldini, Tulio C.; Lima, Iara B.; Goncalves, Josemary A.C.; Botelho, Suzana; Tobias, Carmen C.B.; Ridenti, Marco A.; Pascholati, Paulo R.; Fonte, Paulo; Mangiarotti, Alessio

    2010-01-01

    Full text. The electron drift velocity characterizes the electric conductivity of weakly ionized gases and is one of the most important transport parameters for simulation and modeling of radiation detectors and plasma discharges. This work presents the results of electron drift velocity as a function of the reduced electric field obtained in nitrogen and isobutane by the Pulsed Townsend technique. Due to its excellent timing properties, isobutane is a common component of standard mixtures used in RPCs (Resistive Plate Chambers), however, at moderate electric fields strength (50 Td 10 Ω·m). The fast electric signals generated is amplified and were digitalized in a 1 GHz bandwidth oscilloscope to measure the electrons transit time and to calculate the electron drift velocity in different gaps between anode and cathode. As the timing information presented in the fast electric signal originated in the anode is significant in our application, the amplifier circuit had to hold special features in order to preserve the signal shape. The linear amplifier used, based on the BGM1013 integrated circuit (Philips R), reaches up to 2.1 GHz bandwidth with 35.5 dB gain and was developed and built at Laboratory of Instrumentation and Experimental Particles Physics/Portugal. In order to validate this method, measurements were initially carried out in pure nitrogen, in reduced electric fields ranging from 148 to 194 Td. These results showed good agreement with those found in the literature for this largely investigated gas. The measurements of electron drift velocities in pure isobutane were performed as a function of reduced electric field from 190 to 211 Td. The results were concordant, within the experimental errors, with the values simulated by the Imonte (version 4.5) code and the data recently obtained by our group. (author)

  12. Experimental and clinical trial of measuring urinary velocity with the pitot tube and a transrectal ultrasound guided video urodynamic system.

    Science.gov (United States)

    Tsujimoto, Yukio; Nose, Yorihito; Ohba, Kenkichi

    2003-01-01

    The pitot tube is a common device to measure flow velocity. If the pitot tube is used as an urodynamic catheter, urinary velocity and urethral pressure may be measured simultaneously. However, to our knowledge, urodynamic studies with the pitot tube have not been reported. We experimentally and clinically evaluated the feasibility of the pitot tube to measure urinary velocity with a transrectal ultrasound guided video urodynamic system. We carried out a basal experiment measuring flow velocity in model urethras of 4.5-8.0 mm in inner diameter with a 12-Fr pitot tube. In a clinical trial, 79 patients underwent transrectal ultrasound guided video urodynamic studies with the 12-Fr pitot tube. Urinary velocity was calculated from dynamic pressure (Pd) with the pitot tube formula and the correcting equation according to the results of the basal experiment. Velocity measured by the pitot tube was proportional to the average velocity in model urethras and the coefficients were determined by diameters of model urethras. We obtained a formula to calculate urinary velocity from the basal experiment. The urinary velocity could be obtained in 32 of 79 patients. Qmax was 8.1 +/- 4.3 mL/s (mean +/- SD; range, 18.4-1.3 mL/s), urethral diameter was 7.3 +/- 3.0 mm (mean +/- SD; range, 18.7-4.3 mm) and urinary velocity was 69.4 +/- 43.6 (mean +/- SD; range, 181.3-0 cm/s) at maximum flow rate. The correlation coefficient of Qmax measured by a flowmeter versus Qdv flow rate calculated with urethral diameter and velocity was 0.41 without significant difference. The use of the pitot tube as an urodynamic catheter to a transrectal ultrasound-guided video urodynamic system can measure urethral pressure, diameter and urinary velocity simultaneously. However, a thinner pitot tube and further clinical trials are needed to obtain more accurate results.

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

    Energy Technology Data Exchange (ETDEWEB)

    Parchevsky, K. V.; Zhao, J.; Hartlep, T.; Kosovichev, A. G., E-mail: akosovichev@solar.stanford.edu [Stanford University, HEPL, Stanford, CA 94305 (United States)

    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.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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.

  15. Can Confirmation Measures Reflect Statistically Sound Dependencies in Data? The Concordance-based Assessment

    Directory of Open Access Journals (Sweden)

    Susmaga Robert

    2018-03-01

    Full Text Available The paper considers particular interestingness measures, called confirmation measures (also known as Bayesian confirmation measures, used for the evaluation of “if evidence, then hypothesis” rules. The agreement of such measures with a statistically sound (significant dependency between the evidence and the hypothesis in data is thoroughly investigated. The popular confirmation measures were not defined to possess such form of agreement. However, in error-prone environments, potential lack of agreement may lead to undesired effects, e.g. when a measure indicates either strong confirmation or strong disconfirmation, while in fact there is only weak dependency between the evidence and the hypothesis. In order to detect and prevent such situations, the paper employs a coefficient allowing to assess the level of dependency between the evidence and the hypothesis in data, and introduces a method of quantifying the level of agreement (referred to as a concordance between this coefficient and the measure being analysed. The concordance is characterized and visualised using specialized histograms, scatter-plots, etc. Moreover, risk-related interpretations of the concordance are introduced. Using a set of 12 confirmation measures, the paper presents experiments designed to establish the actual concordance as well as other useful characteristics of the measures.

  16. Measuring Young Children's Alphabet Knowledge: Development and Validation of Brief Letter-Sound Knowledge Assessments

    Science.gov (United States)

    Piasta, Shayne B.; Phillips, Beth M.; Williams, Jeffrey M.; Bowles, Ryan P.; Anthony, Jason L.

    2016-01-01

    Early childhood teachers are increasingly encouraged to support children's development of letter-sound abilities. Assessment of letter-sound knowledge is key in planning for effective instruction, yet the letter-sound knowledge assessments currently available and suitable for preschool-age children demonstrate significant limitations. The purpose…

  17. Development of a Duplex Ultrasound Simulator and Preliminary Validation of Velocity Measurements in Carotid Artery Models.

    Science.gov (United States)

    Zierler, R Eugene; Leotta, Daniel F; Sansom, Kurt; Aliseda, Alberto; Anderson, Mark D; Sheehan, Florence H

    2016-07-01

    Duplex ultrasound scanning with B-mode imaging and both color Doppler and Doppler spectral waveforms is relied upon for diagnosis of vascular pathology and selection of patients for further evaluation and treatment. In most duplex ultrasound applications, classification of disease severity is based primarily on alterations in blood flow velocities, particularly the peak systolic velocity (PSV) obtained from Doppler spectral waveforms. We developed a duplex ultrasound simulator for training and assessment of scanning skills. Duplex ultrasound cases were prepared from 2-dimensional (2D) images of normal and stenotic carotid arteries by reconstructing the common carotid, internal carotid, and external carotid arteries in 3 dimensions and computationally simulating blood flow velocity fields within the lumen. The simulator displays a 2D B-mode image corresponding to transducer position on a mannequin, overlaid by color coding of velocity data. A spectral waveform is generated according to examiner-defined settings (depth and size of the Doppler sample volume, beam steering, Doppler beam angle, and pulse repetition frequency or scale). The accuracy of the simulator was assessed by comparing the PSV measured from the spectral waveforms with the true PSV which was derived from the computational flow model based on the size and location of the sample volume within the artery. Three expert examiners made a total of 36 carotid artery PSV measurements based on the simulated cases. The PSV measured by the examiners deviated from true PSV by 8% ± 5% (N = 36). The deviation in PSV did not differ significantly between artery segments, normal and stenotic arteries, or examiners. To our knowledge, this is the first simulation of duplex ultrasound that can create and display real-time color Doppler images and Doppler spectral waveforms. The results demonstrate that an examiner can measure PSV from the spectral waveforms using the settings on the simulator with a mean absolute error

  18. First Absolutely Calibrated Localized Measurements of Ion Velocity in the MST in Locked and Rotating Plasmas

    Science.gov (United States)

    Baltzer, M.; Craig, D.; den Hartog, D. J.; Nornberg, M. D.; Munaretto, S.

    2015-11-01

    An Ion Doppler Spectrometer (IDS) is used on MST for high time-resolution passive and active measurements of impurity ion emission. Absolutely calibrated measurements of flow are difficult because the spectrometer records data within 0.3 nm of the C+5 line of interest, and commercial calibration lamps do not produce lines in this narrow range . A novel optical system was designed to absolutely calibrate the IDS. The device uses an UV LED to produce a broad emission curve in the desired region. A Fabry-Perot etalon filters this light, cutting transmittance peaks into the pattern of the LED emission. An optical train of fused silica lenses focuses the light into the IDS with f/4. A holographic diffuser blurs the light cone to increase homogeneity. Using this light source, the absolute Doppler shift of ion emissions can be measured in MST plasmas. In combination with charge exchange recombination spectroscopy, localized ion velocities can now be measured. Previously, a time-averaged measurement along the chord bisecting the poloidal plane was used to calibrate the IDS; the quality of these central chord calibrations can be characterized with our absolute calibration. Calibration errors may also be quantified and minimized by optimizing the curve-fitting process. Preliminary measurements of toroidal velocity in locked and rotating plasmas will be shown. This work has been supported by the US DOE.

  19. CSF flow: Correlation between signal void and CSF velocity measured by gated velocity phase-encoded MR imaging

    International Nuclear Information System (INIS)

    Mark, A.S.; Feinberg, D.A.

    1986-01-01

    The direction of the cerebrospinal fluid (CSF) flow in the foramen of Monro (FOM) and aqueduct was determined in 15 normal volunteers (5 of whom had also been studied with gated spin-echo sequences) using a cardiac-gated Fourier transform velocity imaging technique (VMR). The VMR showed that the periodic pattern of flow void seen in the aqueduct and FOM on the gated spin-echo images was due to antegrade CSF flow from the lateral ventricles into the third ventricle and aqueduct during systole and retrograde flow from the aqueduct into the third ventricle and lateral ventricles during late diastole. These findings could not be explained if the CSF pulsations originated in the third ventricle, as had been previously proposed, and suggest the lateral ventricles play an important role in the pulsatile motion of CSF

  20. An Electromagnetic Gauge Technique for Measuring Shocked Particle Velocity in Electrically Conductive Samples

    Science.gov (United States)

    Cheng, David; Yoshinaka, Akio

    2014-11-01

    Electromagnetic velocity (EMV) gauges are a class of film gauges which permit the direct in-situ measurement of shocked material flow velocity. The active sensing element, typically a metallic foil, requires exposure to a known external magnetic field in order to produce motional electromotive force (emf). Due to signal distortion caused by mutual inductance between sample and EMV gauge, this technique is typically limited to shock waves in non-conductive materials. In conductive samples, motional emf generated in the EMV gauge has to be extracted from the measured signal which results from the combined effects of both motional emf and voltage changes from induced currents. An electromagnetic technique is presented which analytically models the dynamics of induced current between a copper disk moving as a rigid body with constant 1D translational velocity toward an EMV gauge, where both disk and gauge are exposed to a uniform external static magnetic field. The disk is modelled as a magnetic dipole loop where its Foucault current is evaluated from the characteristics of the fields, whereas the EMV gauge is modelled as a circuit loop immersed in the field of the magnetic dipole loop, the intensity of which is calculated as a function of space and, implicitly, time. Equations of mutual induction are derived and the current induced in the EMV gauge loop is solved, allowing discrimination of the motional emf. Numerical analysis is provided for the step response of the induced EMV gauge current with respect to the Foucault current in the moving copper sample.

  1. Velocity and size distribution measurement of suspension droplets using PDPA technique

    Science.gov (United States)

    Amiri, Shahin; Akbarnozari, Ali; Moreau, Christian; Dolatabadi, Ali

    2015-11-01

    The creation of fine and uniform droplets from a bulk of liquid is a vital process in a variety of engineering applications, such as atomization in suspension plasma spray (SPS) in which the submicron coating materials are injected to the plasma gas through the suspension droplets. The size and velocity of these droplets has a great impact on the interaction of the suspension with the gas flow emanating from a plasma torch and can consequently affect the mechanical and chemical properties of the resultant coatings. In the current study, an aqueous suspension of small glass particles (2-8 μm) was atomized by utilizing an effervescent atomizer of 1 mm orifice diameter which involves bubbling gas (air) directly into the liquid stream. The gas to liquid ratio (GLR) was kept constant at 6% throughout this study. The mass concentration of glass particles varied in the range between 0.5 to 5% in order to investigate the effect of suspension viscosity and surface tension on the droplet characteristics, such as velocity and size distributions. These characteristics were simultaneously measured by using a non-intrusive optical technique, Phase Doppler Particle Anemometry (PDPA), which is based on the light signal scattered from the droplets moving in a measurement volume. The velocity and size distribution of suspension droplets were finally compared to those of distilled water under identical conditions. The results showed a different atomization behaviors due to the reduction in surface tension of the suspension spray.

  2. In-situ measurements of seismic velocities in the San Francisco Bay region...part II

    Science.gov (United States)

    Gibbs, James F.; Fumal, Thomas E.; Borcherdt, Roger D.

    1976-01-01

    Seismic wave velocities (compressional and shear) are important parameters for determining the seismic response characteristics of various geologic units when subjected to strong earthquake ground shaking. Seismic velocities of various units often show a strong correlation with the amounts of damage following large earthquakes and have been used as a basis for certain types of seismic zonation studies. Currently a program is in progress to measure seismic velocities in the San Francisco Bay region at an estimated 150 sites. At each site seismic travel times are measured in drill holes, normally at 2.5-m intervals to a depth of 30 m. Geologic logs are determined from drill hole cuttings, undisturbed samples, and penetrometer samples. The data provide a detailed comparison of geologic and seismic characteristics and provide parameters for estimating strong earthquake ground motions quantitatively at each of the site. A major emphasis of this program is to obtain a detailed comparison of geologic and seismic data on a regional scale for use in seismic zonation. The broad data base available in the San Francisco Bay region suggests using the area as a pilot area for the development of general techniques applicable to other areas.

  3. Steady and Unsteady Velocity Measurements in a Small Turbocharger Turbine with Computational Validation

    Science.gov (United States)

    Karamanis, N.; Palfreyman, D.; Arcoumanis, C.; Martinez-Botas, R. F.

    2006-07-01

    The detailed flow characteristics of three high-pressure-ratio mixed-flow turbines were investigated under both steady and pulsating flow conditions. Two rotors featured a constant inlet blade angle, one with 12 blades and the second with 10. The third rotor was shorter and had a nominally constant incidence angle. The rotors find application on an automotive high-speed large commercial diesel turbocharger. The steady flow entering and exiting the blades has been quantified by a laser Doppler velocimetry system. The measurements were performed at a plane 3.0-mm ahead of the rotor leading edge and 9.5-mm downstream the rotor trailing edge. The turbine test conditions corresponded to the peak efficiency point at two rotational speeds, 29,400 and 41,300-rpm. The results were resolved in a blade-to-blade sense to examine fully the nature of the flow at turbocharger representative conditions. A correlation between the combined effects of incidence and exit flow angle with the isentropic efficiency has been verified. Regarding pulsating flow, the velocity data and their corresponding instantaneous velocity triangles were resolved in a blade-to-blade sense to understand better the complex phenomenon. The results highlighted the potential of a nominally constant incidence design to absorb better the inadequacy of the volute to discharge the exhaust gas uniformly along the blade leading edge. A double vortex rotating in a clockwise sense propagated on the plane normal to the meridional direction. This should be attributed to the effect of the passing blade that was acting as a blockage to the flow. The phenomenon was more pronounced near the suction and pressure surfaces of the blade, but diminished at the mid-passage region where the flow exhibited its best level of guidance. The full mixed flow turbine stage under transient conditions was modelled firstly with a 'steady' inlet and secondly with a 'pulsating' inlet boundary condition. In both cases comparison was made to

  4. Magnetic field dependence of ultrasound velocity in high-Tc superconductors

    International Nuclear Information System (INIS)

    Higgins, M.J.; Goshorn, D.P.; Bhattacharya, S.; Johnston, D.C.

    1989-01-01

    The magnetic field dependence of ultrasound velocity in the superconductor La 1.8 Sr 0.2 CuO 4-y is studied. The sound velocity anomaly near T c is shown to be unambiguously related to superconductivity. Below T c , the sound velocity is found to be sensitive to the dynamics of a pinned flux lattice. A combination of sound velocity and magnetization measurements suggests three regimes of pinning behavior. A generic pinning ''phase diagram'' is obtained in the superconducting state. An anomalous peak effect in the magnetization is also observed at intermediate field strengths

  5. Variations in the electrical short-circuit current decay for recombination lifetime and velocity measurements

    Science.gov (United States)

    Jung, Tae-Won; Lindholm, Fredrik A.; Neugroschel, Arnost

    1987-01-01

    An improved measurement system for electrical short-circuit current decay is presented that extends applicability of the method to silicon solar cells having an effective lifetime as low as 1 microsec. The system uses metal/oxide/semiconductor transistors as voltage-controlled switches. Advances in theory developed here increase precision and sensitivity in the determination of the minority-carrier recombination lifetime and recombination velocity. A variation of the method, which exploits measurements made on related back-surface field and back-ohmic contact devices, further improves precision and sensitivity. The improvements are illustrated by application to 15 different silicon solar cells.

  6. Supplement to procedures, analysis, and comparison of groundwater velocity measurement methods for unconfined aquifers

    International Nuclear Information System (INIS)

    Zinkl, R.J.; Kearl, P.M.

    1988-09-01

    This report is a supplement to Procedures, Analysis, and Comparison of Groundwater Velocity Measurement Methods for Unconfined Aquifers and provides computer program descriptions, type curves, and calculations for the analysis of field data in determining groundwater velocity in unconfined aquifers. The computer programs analyze bail or slug tests, pumping tests, Geoflo Meter data, and borehole dilution data. Appendix A is a description of the code, instructions for using the code, an example data file, and the calculated results to allow checking the code after installation on the user's computer. Calculations, development of formulas, and correction factors for the various programs are presented in Appendices B through F. Appendix G provides a procedure for calculating transmissivity and specific yield for pumping tests performed in unconfined aquifers

  7. Measuring saccade peak velocity using a low-frequency sampling rate of 50 Hz.

    Science.gov (United States)

    Wierts, Roel; Janssen, Maurice J A; Kingma, Herman

    2008-12-01

    During the last decades, small head-mounted video eye trackers have been developed in order to record eye movements. Real-time systems-with a low sampling frequency of 50/60 Hz-are used for clinical vestibular practice, but are generally considered not to be suited for measuring fast eye movements. In this paper, it is shown that saccadic eye movements, having an amplitude of at least 5 degrees, can, in good approximation, be considered to be bandwidth limited up to a frequency of 25-30 Hz. Using the Nyquist theorem to reconstruct saccadic eye movement signals at higher temporal resolutions, it is shown that accurate values for saccade peak velocities, recorded at 50 Hz, can be obtained, but saccade peak accelerations and decelerations cannot. In conclusion, video eye trackers sampling at 50/60 Hz are appropriate for detecting the clinical relevant saccade peak velocities in contrast to what has been stated up till now.

  8. Pulse wave velocity 24-hour monitoring with one-site measurements by oscillometry

    Directory of Open Access Journals (Sweden)

    Posokhov IN

    2013-02-01

    Full Text Available Igor N PosokhovHemodynamic Laboratory Ltd, Nizhniy Novgorod, RussiaAbstract: This review describes issues for the estimation of pulse wave velocity (PWV under ambulatory conditions using oscillometric systems. The difference between the principles of measuring the PWV by the standard method and by oscillometry is shown, and information on device validation studies is summarized. It was concluded that currently oscillometry is a method that is very convenient to use in the 24-hour monitoring of the PWV, is relatively accurate, and is reasonably comfortable for the patient. Several indices with the same principles as those in the analysis of blood pressure in ambulatory monitoring of blood pressure, namely the assessment of load, variability, and circadian rhythm, are proposed.Keywords: pulse wave velocity, 24-hour monitoring, oscillometry

  9. Crustal composition in the Hidaka Metamorphic Belt estimated from seismic velocity by laboratory measurements

    Science.gov (United States)

    Yamauchi, K.; Ishikawa, M.; Sato, H.; Iwasaki, T.; Toyoshima, T.

    2015-12-01

    To understand the dynamics of the lithosphere in subduction systems, the knowledge of rock composition is significant. However, rock composition of the overriding plate is still poorly understood. To estimate rock composition of the lithosphere, it is an effective method to compare the elastic wave velocities measured under the high pressure and temperature condition with the seismic velocities obtained by active source experiment and earthquake observation. Due to an arc-arc collision in central Hokkaido, middle to lower crust is exposed along the Hidaka Metamorphic Belt (HMB), providing exceptional opportunities to study crust composition of an island arc. Across the HMB, P-wave velocity model has been constructed by refraction/wide-angle reflection seismic profiling (Iwasaki et al., 2004). Furthermore, because of the interpretation of the crustal structure (Ito, 2000), we can follow a continuous pass from the surface to the middle-lower crust. We corrected representative rock samples from HMB and measured ultrasonic P-wave (Vp) and S-wave velocities (Vs) under the pressure up to 1.0 GPa in a temperature range from 25 to 400 °C. For example, the Vp values measured at 25 °C and 0.5 GPa are 5.88 km/s for the granite (74.29 wt.% SiO2), 6.02-6.34 km/s for the tonalites (66.31-68.92 wt.% SiO2), 6.34 km/s for the gneiss (64.69 wt.% SiO2), 6.41-7.05 km/s for the amphibolites (50.06-51.13 wt.% SiO2), and 7.42 km/s for the mafic granulite (50.94 wt.% SiO2). And, Vp of tonalites showed a correlation with SiO2 (wt.%). Comparing with the velocity profiles across the HMB (Iwasaki et al., 2004), we estimate that the lower to middle crust consists of amphibolite and tonalite, and the estimated acoustic impedance contrast between them suggests an existence of a clear reflective boundary, which accords well to the obtained seismic reflection profile (Iwasaki et al., 2014). And, we can obtain the same tendency from comparing measured Vp/Vs ratio and Vp/Vs ratio structure model

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. In vivo measurement of mechanical properties of human long bone by using sonic sound

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, M. Jayed, E-mail: zed.hossain06@gmail.com; Rahman, M. Moshiur, E-mail: razib-121@yahoo.com; Alam, Morshed [Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000 (Bangladesh)

    2016-07-12

    Vibration analysis has evaluated as non-invasive techniques for the in vivo assessment of bone mechanical properties. The relation between the resonant frequencies, long bone geometry and mechanical properties can be obtained by vibration analysis. In vivo measurements were performed on human ulna as a simple beam model with an experimental technique and associated apparatus. The resonant frequency of the ulna was obtained by Fast Fourier Transformation (FFT) analysis of the vibration response of piezoelectric accelerometer. Both elastic modulus and speed of the sound were inferred from the resonant frequency. Measurement error in the improved experimental setup was comparable with the previous work. The in vivo determination of bone elastic response has potential value in screening programs for metabolic bone disease, early detection of osteoporosis and evaluation of skeletal effects of various therapeutic modalities.

  12. Density and speed of sound of lithium bromide with organic solvents: Measurement and correlation

    Energy Technology Data Exchange (ETDEWEB)

    Zafarani-Moattar, Mohammed Taghi [Department of Physical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 51664 (Iran, Islamic Republic of); Research Institute of Fundamental Sciences, Tabriz 51664 (Iran, Islamic Republic of)], E-mail: zafarani47@yahoo.com; Shekaari, Hemayat [Department of Physical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 51664 (Iran, Islamic Republic of); Research Institute of Fundamental Sciences, Tabriz 51664 (Iran, Islamic Republic of)

    2007-12-15

    Densities, {rho}, and speed of sound, u, of the solutions of LiBr with non-aqueous solvents (methanol, ethanol, 2-propanol, acetone, and acetonitrile) having a wide range of dielectric constants were measured at T = 298.15 K. Also, these measurements were made for the system (LiBr + N,N-dimethylacetamide) at T = 323.15 K. For the investigated systems, the limiting values for apparent molar volume, V{sub {phi}}{sup 0}, and the apparent molar isentropic compressibility, {kappa}{sub {phi}}{sup 0}, were obtained from the Redlich-Mayer and an abbreviated form of the Pitzer equations. The Pitzer and NRTL equations were satisfactorily used for the correlation of apparent molar volumes, V{sub {phi}}, and the apparent molar isentropic compressibility, {kappa}{sub {phi}}, values of the studied systems.

  13. The need for speed: escape velocity and dynamical mass measurements of the Andromeda galaxy

    Science.gov (United States)

    Kafle, Prajwal R.; Sharma, Sanjib; Lewis, Geraint F.; Robotham, Aaron S. G.; Driver, Simon P.

    2018-04-01

    Our nearest large cosmological neighbour, the Andromeda galaxy (M31), is a dynamical system, and an accurate measurement of its total mass is central to our understanding of its assembly history, the life-cycles of its satellite galaxies, and its role in shaping the Local Group environment. Here, we apply a novel approach to determine the dynamical mass of M31 using high-velocity Planetary Nebulae, establishing a hierarchical Bayesian model united with a scheme to capture potential outliers and marginalize over tracers unknown distances. With this, we derive the escape velocity run of M31 as a function of galactocentric distance, with both parametric and non-parametric approaches. We determine the escape velocity of M31 to be 470 ± 40 km s-1 at a galactocentric distance of 15 kpc, and also, derive the total potential of M31, estimating the virial mass and radius of the galaxy to be 0.8 ± 0.1 × 1012 M⊙ and 240 ± 10 kpc, respectively. Our M31 mass is on the low side of the measured range, this supports the lower expected mass of the M31-Milky Way system from the timing and momentum arguments, satisfying the H I constraint on circular velocity between 10 ≲ R/ kpc < 35, and agreeing with the stellar mass Tully-Fisher relation. To place these results in a broader context, we compare them to the key predictions of the ΛCDM cosmological paradigm, including the stellar-mass-halo-mass and the dark matter halo concentration-virial mass correlation, and finding it to be an outlier to this relation.

  14. Fourth sound in relativistic superfluidity theory

    International Nuclear Information System (INIS)

    Vil'chinskij, S.I.; Fomin, P.I.

    1995-01-01

    The Lorentz-covariant equations describing propagation of the fourth sound in the relativistic theory of superfluidity are derived. The expressions for the velocity of the fourth sound are obtained. The character of oscillation in sound is determined

  15. Dissipation in vibrating superleak second sound transducers

    International Nuclear Information System (INIS)

    Giordano, N.

    1985-01-01

    We have performed an experimental study of the generation and detection of second sound in 4 He using vibrating superleak second sound transducers. At temperatures well below T/sub lambda/ and for low driving amplitudes, the magnitude of the generated second sound wave is proportional to the drive amplitude. However, near T/sub lambda/ and for high drive amplitudes this is no longer the case--instead, the second sound amplitude saturates. In this regime we also find that overtones of the drive frequency are generated. Our results suggest that this behavior is due to critical velocity effects in the pores of the superleak in the generator transducer. This type of measurement may prove to be a useful way in which to study critical velocity effects in confined geometries

  16. New sensor for measurement of low air flow velocity. Phase I final report

    International Nuclear Information System (INIS)

    Hashemian, H.M.; Hashemian, M.; Riggsbee, E.T.

    1995-08-01

    The project described here is the Phase I feasibility study of a two-phase program to integrate existing technologies to provide a system for determining air flow velocity and direction in radiation work areas. Basically, a low air flow sensor referred to as a thermocouple flow sensor has been developed. The sensor uses a thermocouple as its sensing element. The response time of the thermocouple is measured using an existing in-situ method called the Loop Current Step Response (LCSR) test. The response time results are then converted to a flow signal using a response time-versus-flow correlation. The Phase I effort has shown that a strong correlation exists between the response time of small diameter thermocouples and the ambient flow rate. As such, it has been demonstrated that thermocouple flow sensors can be used successfully to measure low air flow rates that can not be measured with conventional flow sensors. While the thermocouple flow sensor developed in this project was very successful in determining air flow velocity, determining air flow direction was beyond the scope of the Phase I project. Nevertheless, work was performed during Phase I to determine how the new flow sensor can be used to determine the direction, as well as the velocity, of ambient air movements. Basically, it is necessary to use either multiple flow sensors or move a single sensor in the monitoring area and make flow measurements at various locations sweeping the area from top to bottom and from left to right. The results can then be used with empirical or physical models, or in terms of directional vectors to estimate air flow patterns. The measurements can be made continuously or periodically to update the flow patterns as they change when people and objects are moved in the monitoring area. The potential for using multiple thermocouple flow sensors for determining air flow patterns will be examined in Phase II

  17. Measurement of the drift velocities of electrons and holes in high-ohmic silicon

    International Nuclear Information System (INIS)

    Scharf, Christian

    2014-02-01

    Measurements of the drift velocities of electrons and holes as a function of the electric field and the temperature in high-ohmic silicon of crystal orientation are presented. Significant differences between our results and literature values are observed. A new parametrization of the mobility is introduced. Current transients of n-type pad diodes, generated by fast laser pulses, were investigated in order to determine the drift velocity of electrons and holes separately. Two diodes of high-ohmic silicon (1.5 kΩcm and 5.5 kΩcm) from different manufacturers were investigated as cross check. The drift velocities were determined at electric fields ranging from 5 kV/cm to 50 kV/cm at temperatures ranging from 233 K to 333 K. The mobility parameters were obtained by fitting a simulation of charge drift in silicon to the measurements. Using the convolution theorem the response function of the read-out circuit was determined with the Fourier transforms of the measurement and the simulation. The simulated transient current pulses with the new mobility parametrization are consistent with the measured ones for the temperature and electric field range investigated here. Additionally, the mobility results from the fit are consistent with the mobility determined using the simpler time-of-flight method in the field range where this method is applicable. However, our measurements show a difference of up to 14 % to the values by Canali et al. (1971). The difference to the mobility parametrization by Jacoboni et al. (1977) is up to 24 % while this parametrization is widely used for simulations of the direction due to the lack of data for silicon.

  18. A cell impedance measurement device for the cytotoxicity assay dependent on the velocity of supplied toxic fluid

    Science.gov (United States)

    Kang, Yoon-Tae; Kim, Min-Ji; Cho, Young-Ho

    2018-04-01

    We present a cell impedance measurement chip capable of characterizing the toxic response of cells depending on the velocity of the supplied toxic fluid. Previous impedance-based devices using a single open-top chamber have been limited to maintaining a constant supply velocity, and devices with a single closed-top chamber present difficulties in simultaneous cytotoxicity assay for varying levels of supply velocities. The present device, capable of generating constant and multiple levels of toxic fluid velocity simultaneously within a single stepwise microchannel, performs a cytotoxicity assay dependent on toxic fluid velocity, in order to find the effective velocity of toxic fluid to cells for maximizing the cytotoxic effect. We analyze the cellular toxic response of 5% ethanol media supplied to cancer cells within a toxic fluid velocity range of 0-8.3 mm s-1. We observe the velocity-dependent cell detachment rate, impedance, and death rate. We find that the cell detachment rate decreased suddenly to 2.4% at a velocity of 4.4 mm s-1, and that the change rates of cell resistance and cell capacitance showed steep decreases to 8% and 41%, respectively, at a velocity of 5.7 mm s-1. The cell death rate and impedance fell steeply to 32% at a velocity of 5.7 mm s-1. We conclude that: (1) the present device is useful in deciding on the toxic fluid velocity effective to cytotoxicity assay, since the cellular toxic response is dependent on the velocity of toxic fluid, and; (2) the cell impedance analysis facilitates a finer cellular response analysis, showing better correlation with the cell death rate, compared to conventional visual observation. The present device, capable of performing the combinational analysis of toxic fluid velocity and cell impedance, has potential for application to the fine cellular toxicity assay of drugs with proper toxic fluid velocity.

  19. LOFT experimental measurements uncertainty analyses. Volume XX. Fluid-velocity measurement using pulsed-neutron activation

    International Nuclear Information System (INIS)

    Lassahn, G.D.; Taylor, D.J.N.

    1982-08-01

    Analyses of uncertainty components inherent in pulsed-neutron-activation (PNA) measurements in general and the Loss-of-Fluid-Test (LOFT) system in particular are given. Due to the LOFT system's unique conditions, previously-used techniques were modified to make the volocity measurement. These methods render a useful, cost-effective measurement with an estimated uncertainty of 11% of reading

  20. Calculation of acoustic field based on laser-measured vibration velocities on ultrasonic transducer surface

    Science.gov (United States)

    Hu, Liang; Zhao, Nannan; Gao, Zhijian; Mao, Kai; Chen, Wenyu; Fu, Xin

    2018-05-01

    Determination of the distribution of a generated acoustic field is valuable for studying ultrasonic transducers, including providing the guidance for transducer design and the basis for analyzing their performance, etc. A method calculating the acoustic field based on laser-measured vibration velocities on the ultrasonic transducer surface is proposed in this paper. Without knowing the inner structure of the transducer, the acoustic field outside it can be calculated by solving the governing partial differential equation (PDE) of the field based on the specified boundary conditions (BCs). In our study, the BC on the transducer surface, i.e. the distribution of the vibration velocity on the surface, is accurately determined by laser scanning measurement of discrete points and follows a data fitting computation. In addition, to ensure the calculation accuracy for the whole field even in an inhomogeneous medium, a finite element method is used to solve the governing PDE based on the mixed BCs, including the discretely measured velocity data and other specified BCs. The method is firstly validated on numerical piezoelectric transducer models. The acoustic pressure distributions generated by a transducer operating in an homogeneous and inhomogeneous medium, respectively, are both calculated by the proposed method and compared with the results from other existing methods. Then, the method is further experimentally validated with two actual ultrasonic transducers used for flow measurement in our lab. The amplitude change of the output voltage signal from the receiver transducer due to changing the relative position of the two transducers is calculated by the proposed method and compared with the experimental data. This method can also provide the basis for complex multi-physical coupling computations where the effect of the acoustic field should be taken into account.

  1. The effects of breath-holding on pulmonary regurgitation measured by cardiovascular magnetic resonance velocity mapping

    Directory of Open Access Journals (Sweden)

    Babu-Narayan Sonya V

    2009-01-01

    Full Text Available Abstract Background Pulmonary regurgitation is a common and clinically important residual lesion after repair of tetralogy of Fallot. Cardiovascular magnetic resonance (CMR phase contrast velocity mapping is widely used for measurement of pulmonary regurgitant fraction. Breath-hold acquisitions, usually acquired during held expiration, are more convenient than the non-breath-hold approach, but we hypothesized that breath-holding might affect the amount of pulmonary regurgitation. Methods Forty-three adult patients with a previous repair of tetralogy of Fallot and residual pulmonary regurgitation were investigated with CMR. In each, pulmonary regurgitant fraction was measured from velocity maps transecting the pulmonary trunk, acquired during held expiration, held inspiration, by non-breath-hold acquisition, and also from the difference of right and left ventricular stroke volume measurements. Results Pulmonary regurgitant fraction was lower when measured by velocity mapping in held expiration compared with held inspiration, non-breath-hold or stroke volume difference (30.8 vs. 37.0, 35.6, 35.4%, p = 0.00017, 0.0035, 0.026. The regurgitant volume was lower in held expiration than in held inspiration (41.9 vs. 48.3, p = 0.0018. Pulmonary forward flow volume was larger during held expiration than during non-breath-hold (132 vs. 124 ml, p = 0.0024. Conclusion Pulmonary regurgitant fraction was significantly lower in held expiration compared with held inspiration, free breathing and stroke volume difference. Altered airway pressure could be a contributory factor. This information is relevant if breath-hold acquisition is to be substituted for non-breath-hold in the investigation of patients with a view to re-intervention.

  2. Measurement of the dark matter velocity anisotropy profile in galaxy clusters

    International Nuclear Information System (INIS)

    Host, Ole

    2009-01-01

    Dark matter halos contribute the major part of the mass of galaxy clusters and the formation of these cosmological structures have been investigated in numerical simulations. Observations have been found to be in good agreement with the numerical predictions regarding the spatial distribution of dark matter, i.e. the mass profile. However, the dynamics of dark matter in halos has so far proved a greater challenge to probe observationally. We have used observations of 16 relaxed galaxy clusters to show that the dark matter velocity dispersion is larger along the radial direction than along the tangential, and that the magnitude of this velocity anisotropy β varies with radius. This measurement implies that the collective behaviour of dark matter particles is fundamentally different from that of baryonic particles and constrains the self-interaction per unit mass. The radial variation of the anisotropy velocity agrees with the predictions so that, on cluster scales, there is now excellent agreement between numerical predictions and observations regarding the phase space of dark matter.

  3. Direct simultaneous measurement of intraglottal geometry and velocity fields in excised larynges.

    Science.gov (United States)

    Khosla, Sid; Oren, Liran; Ying, Jun; Gutmark, Ephraim

    2014-04-01

    Current theories regarding the mechanisms of phonation are based on assumptions about the aerodynamics between the vocal folds during the closing phase of vocal fold vibration. However, many of these fundamental assumptions have never been validated in a tissue model. In this study, the main objective was to determine the aerodynamics (velocity fields) and the geometry of the medial surface of the vocal folds during the closing phase of vibration. The main hypothesis is that intraglottal vortices are produced during vocal fold closing when the glottal duct has a divergent shape and that these vortices are associated with negative pressures. Experiments using seven excised canine larynges. The particle imaging velocimetry (PIV) method was used to determine the velocity fields at low, mid-, and high subglottal pressures for each larynx. Modifications were made to previously described PIV methodology to allow the measurement of both the intraglottal velocity fields and the position of the medial aspects of the vocal fold. At relatively low subglottal pressures, little to no intraglottal vortices were seen. At mid- and high subglottal pressures, the flow separation vortices occurred and produced maximum negative pressures, relative to atmospheric, of -2.6 to -14.6 cm H2 O. Possible physiological and surgical implications are discussed. Intraglottal vortices produce significant negative pressures at mid- and high subglottal pressures. These vortices may be important in increasing maximum flow declination rate and acoustic intensity. N/A. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

  4. Automatic discrimination of bubbles and slugs in two-phase gas-liquid flow and measurement of the respective velocities

    International Nuclear Information System (INIS)

    Fitremann, J.M.; Guilpin, C.; Postaire, J.

    1976-01-01

    The measurement of the interface velocity in a two-phase gas-liquid flow is a difficult problem, owing to the dispersion of the velocity components of individual bubbles, gas-slugs, droplets, waves, etc. An entirely automatic method is presented, it gives the velocity of slugs and bubbles independently, by discrimination of local phase probe signals into a 'slug' signal and a 'bubble' signal feeding a shape-recognition program. Both discriminated void fractions are also calculated by the apparatus [fr

  5. Measurement of the neutrino velocity with the OPERA detector in the CNGS beam

    CERN Document Server

    Adam, T.; Aleksandrov, A.; Altinok, O.; Alvarez Sanchez, P.; Anokhina, A.; Aoki, S.; Ariga, A.; Ariga, T.; Autiero, D.; Badertscher, A.; Dhahbi, A.Ben; Bertolin, A.; Bozza, C.; Brugiere, T.; Brugnera, R.; Brunet, F.; Brunetti, G.; Buontempo, S.; Carlus, B.; Cavanna, F.; Cazes, A.; Chaussard, L.; Chernyavsky, M.; Chiarella, V.; Chukanov, A.; Colosimo, G.; Crespi, M.; D'Ambrosio, N.; De Lellis, G.; De Serio, M.; Declais, Y.; del Amo Sanchez, P.; Di Capua, F.; Di Crescenzo, A.; Di Ferdinando, D.; Di Marco, N.; Dmitrievsky, S.; Dracos, M.; Duchesneau, D.; Dusini, S.; Dzhatdoev, T.; Ebert, J.; Efthymiopoulos, I.; Egorov, O.; Ereditato, A.; Esposito, L.S.; Favier, J.; Ferber, T.; Fini, R.A.; Fukuda, T.; Garfagnini, A.; Giacomelli, G.; Giorgini, M.; Giovannozzi, M.; Girerd, C.; Goldberg, J.; Gollnitz, C.; Golubkov, D.; Goncharova, L.; Gornushkin, Y.; Grella, G.; Grianti, F.; Gschwendtner, E.; Guerin, C.; Guler, A.M.; Gustavino, C.; Hagner, C.; Hamada, K.; Hara, T.; Enikeev, R.; Hierholzer, M.; Hollnagel, A.; Ieva, M.; Ishida, H.; Ishiguro, K.; Jakovcic, K.; Jollet, C.; Jones, M.; Juget, F.; Kamiscioglu, M.; Kawada, J.; Kim, S.H.; Kimura, M.; Kiritsis, E.; Kitagawa, N.; Klicek, B.; Knuesel, J.; Kodama, K.; Komatsu, M.; Kose, U.; Kreslo, I.; Lazzaro, C.; Lenkeit, J.; Ljubicic, A.; Longhin, A.; Malgin, A.; Mandrioli, G.; Marteau, J.; Matsuo, T.; Matveev, V.; Mauri, N.; Mazzoni, A.; Medinaceli, E.; Meisel, F.; Meregaglia, A.; Migliozzi, P.; Mikado, S.; Missiaen, D.; Monacelli, P.; Morishima, K.; Moser, U.; Muciaccia, M.T.; Naganawa, N.; Naka, T.; Nakamura, M.; Nakano, T.; Nakatsuka, Y.; Naumov, D.; Nikitina, V.; Nitti, F.; Ogawa, S.; Okateva, N.; Olchevsky, A.; Palamara, O.; Paoloni, A.; Park, B.D.; Park, I.G.; Pastore, A.; Patrizii, Laura; Pennacchio, E.; Pessard, H.; Pistillo, C.; Polukhina, N.; Pozzato, M.; Pretzl, K.; Pupilli, F.; Rescigno, R.; Riguzzi, F.; Roganova, T.; Rokujo, H.; Rosa, G.; Rostovtseva, I.; Rubbia, A.; Russo, A.; Ryasny, V.; Ryazhskaya, O.; Sato, O.; Sato, Y.; Sahnoun, Z.; Schembri, A.; Schuler, J.; Scotto Lavina, L.; Serrano, J.; Shakiryanova, I.; Sheshukov, A.; Shibuya, H.; Shoziyoev, G.; Simone, S.; Sioli, M.; Sirignano, C.; Sirri, G.; Song, J.S.; Spinetti, M.; Stanco, L.; Starkov, N.; Stellacci, S.; Stipcevic, M.; Strauss, T.; Takahashi, S.; Tenti, M.; Terranova, F.; Tezuka, I.; Tioukov, V.; Tolun, P.; N.T. Tran,i; Tufanli, S.; Vilain, P.; Vladimirov, M.; Votano, L.; Vuilleumier, J.L.; Wilquet, G.; Wonsak, B.; Wurtz, J.; Yakushev, V.; Yoon, C.S.; Yoshida, J.; Zaitsev, Y.; Zemskova, S.; Zghiche, A.

    2012-01-01

    The OPERA neutrino experiment at the underground Gran Sasso Laboratory has measured the velocity of neutrinos from the CERN CNGS beam over a baseline of about 730 km with much higher accuracy than previous studies conducted with accelerator neutrinos. The measurement is based on high-statistics data taken by OPERA in the years 2009, 2010 and 2011. Dedicated upgrades of the CNGS timing system and of the OPERA detector, as well as a high precision geodesy campaign for the measurement of the neutrino baseline, allowed reaching comparable systematic and statistical accuracies. An early arrival time of CNGS muon neutrinos with respect to the one computed assuming the speed of light in vacuum of (60.7 \\pm 6.9 (stat.) \\pm 7.4 (sys.)) ns was measured. This anomaly corresponds to a relative difference of the muon neutrino velocity with respect to the speed of light (v-c)/c = (2.48 \\pm 0.28 (stat.) \\pm 0.30 (sys.)) \\times 10-5.

  6. Synchronous Surface Pressure and Velocity Measurements of standard model in hypersonic flow

    Directory of Open Access Journals (Sweden)

    Zhijun Sun

    2018-01-01

    Full Text Available Experiments in the Hypersonic Wind tunnel of NUAA(NHW present synchronous measurements of bow shockwave and surface pressure of a standard blunt rotary model (AGARD HB-2, which was carried out in order to measure the Mach-5-flow above a blunt body by PIV (Particle Image Velocimetry as well as unsteady pressure around the rotary body. Titanium dioxide (Al2O3 Nano particles were seeded into the flow by a tailor-made container. With meticulous care designed optical path, the laser was guided into the vacuum experimental section. The transient pressure was obtained around model by using fast-responding pressure-sensitive paint (PSPsprayed on the model. All the experimental facilities were controlled by Series Pulse Generator to ensure that the data was time related. The PIV measurements of velocities in front of the detached bow shock agreed very well with the calculated value, with less than 3% difference compared to Pitot-pressure recordings. The velocity gradient contour described in accord with the detached bow shock that showed on schlieren. The PSP results presented good agreement with the reference data from previous studies. Our work involving studies of synchronous shock-wave and pressure measurements proved to be encouraging.

  7. Measurements of 3D velocity and scalar field for a film-cooled airfoil trailing edge

    Energy Technology Data Exchange (ETDEWEB)

    Benson, Michael J.; Elkins, Christopher J.; Eaton, John K. [Stanford University, Department of Mechanical Engineering, Stanford, CA (United States)

    2011-08-15

    The 3D velocity and concentration fields have been measured for flow in a pressure side cutback trailing edge film cooling geometry consisting of rectangular film cooling slots separated by tapered lands. The velocity field was measured using conventional magnetic resonance velocimetry, and the concentration distribution was measured with a refined magnetic resonance concentration technique that yields experimental uncertainties for the concentration between 5 and 6%. All experiments were performed in water. A separation bubble behind the slot lip entrains coolant and promotes rapid turbulent mixing at the upper edge of the coolant jet. Vortices from inside the slot feed channel and on the upper sides of the lands rapidly distort the initially rectangular shape of the coolant stream and sweep mainstream flow toward the airfoil surface. The vortices also prevent any coolant from reaching the upper surfaces of the land. At the trailing edge, a second separation region exists in the blunt trailing edge wake. The flow forms suction side streaks behind the land tips, as well as streaks behind the slot centers on the pressure side. The peak coolant concentrations in the streaks remain above 25% through the end of the measurement domain, over 30 slot heights downstream. (orig.)

  8. Velocity and pressure measurements in guide vane clearance gap of a low specific speed Francis turbine

    Science.gov (United States)

    Thapa, B. S.; Dahlhaug, O. G.; Thapa, B.

    2016-11-01

    In Francis turbine, a small clearance gap between the guide vanes and the cover plates is usually required to pivot guide vanes as a part of governing system. Deflection of cover plates and erosion of mating surfaces causes this gap to increase from its design value. The clearance gap induces the secondary flow in the distributor system. This effects the main flow at the runner inlet, which causes losses in efficiency and instability. A guide vane cascade of a low specific speed Francis turbine has been developed for experimental investigations. The test setup is able to produce similar velocity distributions at the runner inlet as that of a reference prototype turbine. The setup is designed for particle image velocimetry (PIV) measurements from the position of stay vane outlet to the position of runner inlet. In this study, velocity and pressure measurements are conducted with 2 mm clearance gap on one side of guide vane. Leakage flow is observed and measured together with pressure measurements. It is concluded that the leakage flow behaves as a jet and mixes with the main flow in cross-wise direction and forms a vortex filament. This causes non-uniform inlet flow conditions at runner blades.

  9. Development of a single well dilution probe for groundwater velocity measurements

    International Nuclear Information System (INIS)

    Jain, S.K.; Santra, A.B.; Kulkarni, U.P.; Rao, S.M.

    1982-01-01

    The paper describes the development and design of a single well dilution probe for the measurement of groundwater velocities at different sections of the borehole. In this probe, the radioactive tracer is introduced in the measuring volume by dissolving a gelatine capsule containing the tracer. The continuous mixing of the tracer solution is achieved by a specially designed magnetic stirrer. To prevent vertical flows, the measuring volume is sealed off in the bore-hole at the top and bottom by inflator rubber tubes which are inflated by compressed air from the ground surface. The concentration of the gamma tracer solution is measured 'insitu' by a NaI crystal scintillation detector incorporated in the probe. (author)

  10. Positive and negative streamers in ambient air: measuring diameter, velocity and dissipated energy

    Energy Technology Data Exchange (ETDEWEB)

    Briels, T M P; Kos, J; Van Veldhuizen, E M; Ebert, U [Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600 MB Eindhoven (Netherlands); Winands, G J J [Department of Electrical Engineering, Technische Universiteit Eindhoven, PO Box 513, 5600 MB Eindhoven (Netherlands)], E-mail: e.m.v.veldhuizen@tue.nl, E-mail: ebert@cwi.nl

    2008-12-07

    Positive and negative streamers are studied in ambient air at 1 bar; they emerge from a needle electrode placed 40 mm above a planar electrode. The amplitudes of the applied voltage pulses range from 5 to 96 kV; most pulses have rise times of 30 ns or shorter. Diameters, velocities and energies of the streamers are measured. Two regimes are identified; a low voltage regime where only positive streamers appear and a high voltage regime where both positive and negative streamers exist. Below 5 kV, no streamers emerge. In the range from 5 to 40 kV, positive streamers form, while the negative discharges only form a glowing cloud at the electrode tip, but no streamers. For 5-20 kV, diameters and velocities of the positive streamers have the minimal values of d = 0.2 mm and v {approx} 10{sup 5} m s{sup -1}. For 20-40 kV, their diameters increase by a factor of 6 while the voltage increases only by a factor of 2. Above the transition value of 40 kV, streamers of both polarities form; they strongly resemble each other, though the positive ones propagate further; their diameters continue to increase with applied voltage. For 96 kV, positive streamers attain diameters of 3 mm and velocities of 4 x 10{sup 6} m s{sup -1}; negative streamers are about 20% slower and thinner. An empirical fit formula for the relation between velocity v and diameter d is v = 0.5d{sup 2} mm{sup -1} ns{sup -1} for both polarities. Streamers of both polarities dissipate energies of the order of several millijoules per streamer while crossing the gap.

  11. Positive and negative streamers in ambient air: measuring diameter, velocity and dissipated energy

    International Nuclear Information System (INIS)

    Briels, T M P; Kos, J; Van Veldhuizen, E M; Ebert, U; Winands, G J J

    2008-01-01

    Positive and negative streamers are studied in ambient air at 1 bar; they emerge from a needle electrode placed 40 mm above a planar electrode. The amplitudes of the applied voltage pulses range from 5 to 96 kV; most pulses have rise times of 30 ns or shorter. Diameters, velocities and energies of the streamers are measured. Two regimes are identified; a low voltage regime where only positive streamers appear and a high voltage regime where both positive and negative streamers exist. Below 5 kV, no streamers emerge. In the range from 5 to 40 kV, positive streamers form, while the negative discharges only form a glowing cloud at the electrode tip, but no streamers. For 5-20 kV, diameters and velocities of the positive streamers have the minimal values of d = 0.2 mm and v ∼ 10 5 m s -1 . For 20-40 kV, their diameters increase by a factor of 6 while the voltage increases only by a factor of 2. Above the transition value of 40 kV, streamers of both polarities form; they strongly resemble each other, though the positive ones propagate further; their diameters continue to increase with applied voltage. For 96 kV, positive streamers attain diameters of 3 mm and velocities of 4 x 10 6 m s -1 ; negative streamers are about 20% slower and thinner. An empirical fit formula for the relation between velocity v and diameter d is v = 0.5d 2 mm -1 ns -1 for both polarities. Streamers of both polarities dissipate energies of the order of several millijoules per streamer while crossing the gap.

  12. The low-frequency sound power measuring technique for an underwater source in a non-anechoic tank

    Science.gov (United States)

    Zhang, Yi-Ming; Tang, Rui; Li, Qi; Shang, Da-Jing

    2018-03-01

    In order to determine the radiated sound power of an underwater source below the Schroeder cut-off frequency in a non-anechoic tank, a low-frequency extension measuring technique is proposed. This technique is based on a unique relationship between the transmission characteristics of the enclosed field and those of the free field, which can be obtained as a correction term based on previous measurements of a known simple source. The radiated sound power of an unknown underwater source in the free field can thereby be obtained accurately from measurements in a non-anechoic tank. To verify the validity of the proposed technique, a mathematical model of the enclosed field is established using normal-mode theory, and the relationship between the transmission characteristics of the enclosed and free fields is obtained. The radiated sound power of an underwater transducer source is tested in a glass tank using the proposed low-frequency extension measuring technique. Compared with the free field, the radiated sound power level of the narrowband spectrum deviation is found to be less than 3 dB, and the 1/3 octave spectrum deviation is found to be less than 1 dB. The proposed testing technique can be used not only to extend the low-frequency applications of non-anechoic tanks, but also for measurement of radiated sound power from complicated sources in non-anechoic tanks.

  13. Measurement of one-way velocity of light and light-year

    Science.gov (United States)

    Chen, Shao-Guang

    For space science and astronomy the fundamentality of one-way velocity of light (OWVL) is selfevident. The measurement of OWVL (distance / interval) and the clock synchronization with light-signal transfer make a logical circulation. This means that OWVL could not be directly measured but only come indirectly from astronomical method (Romer's Io eclipse and Bradley's sidereal aberration). Furthermore, the light-year by definitional OWVL and the trigonometry distance with AU are also un-measurable. In this report two methods of clock synchronization to solve this problem were proposed: The arriving-time difference of longitudinal-transverse wave (Ts - Tp) or ordinary-extraordinary light (Te - To) is measured by single clock at one end of a dual-speed transmission-line, the signal transmission-delay (from sending-end time Tx to receiving-end time Tp or To) calculated with wave-speed ratio is: (Tp -Tx) = (Ts -Tp) / ((Vp / Vs) - 1) or: (To -Tx) = (Te - To) / ((Vo / Ve ) - 1), where (Vp / Vs) = (E / k) 1/2 is Yang's / shear elastic-modulus ratio obtained by comparing two strains at same stress, (Vo / Ve) = (ne / no) is extraordinary/ordinary light refractive-index ratio obtained by comparing two deflection-angles. Then, two clocks at transmission-line two ends can be synchronized directly to measure the one-way velocity of light and light-year, which work as one earthquakestation with single clock measures first-shake-time and the distance to epicenter. The readings Na and Nb of two counters Ca and Cb with distance L are transferred into a computer C by two leads with transmission-delay Tac and Tbc respectively. The computer progressing subtraction operation exports steady value: (Nb - Na) = f (Ta - Tb ) + f (Tac - Tbc ), where f is the frequency of light-wave always passing Ca and Cb, Ta and Tb are the count-start time of Ca and Cb respectively. From the transmission-delay possess the spatial translational and rotational invariability, the computer exports steady value

  14. Flow visualizations, velocity measurements, and surface convection measurements in simulated 20.8-cm Nova box amplifier cavities

    International Nuclear Information System (INIS)

    Julien, J.L.; Molishever, E.L.

    1983-01-01

    Reported are fluid mechanics experiments performed in models of the 20.8-cm Nova amplifier lamp and disk cavities. Lamp cavity nitrogen flows are shown, by both flow visualization and velocity measurements, to be acceptably uniform and parallel to the flashlamps. In contrast, the nitrogen flows in the disk cavity are shown to be disordered. Even though disk cavity flows are disordered, the simplest of three proposed nitrogen introduction systems for the disk cavity was found to be acceptable based on convection measurements made at the surfaces of simulated laser disks

  15. GSpecDisp: A matlab GUI package for phase-velocity dispersion measurements from ambient-noise correlations

    Science.gov (United States)

    Sadeghisorkhani, Hamzeh; Gudmundsson, Ólafur; Tryggvason, Ari

    2018-01-01

    We present a graphical user interface (GUI) package to facilitate phase-velocity dispersion measurements of surface waves in noise-correlation traces. The package, called GSpecDisp, provides an interactive environment for the measurements and presentation of the results. The selection of a dispersion curve can be done automatically or manually within the package. The data are time-domain cross-correlations in SAC format, but GSpecDisp measures phase velocity in the spectral domain. Two types of phase-velocity dispersion measurements can be carried out with GSpecDisp; (1) average velocity of a region, and (2) single-pair phase velocity. Both measurements are done by matching the real part of the cross-correlation spectrum with the appropriate Bessel function. Advantages of these two types of measurements are that no prior knowledge about surface-wave dispersion in the region is needed, and that phase velocity can be measured up to that period for which the inter-station distance corresponds to one wavelength. GSpecDisp can measure the phase velocity of Rayleigh and Love waves from all possible components of the noise correlation tensor. First, we briefly present the theory behind the methods that are used, and then describe different modules of the package. Finally, we validate the developed algorithms by applying them to synthetic and real data, and by comparison with other methods. The source code of GSpecDisp can be downloaded from: https://github.com/Hamzeh-Sadeghi/GSpecDisp

  16. WIYN OPEN CLUSTER STUDY. XXIV. STELLAR RADIAL-VELOCITY MEASUREMENTS IN NGC 6819

    International Nuclear Information System (INIS)

    Tabetha Hole, K.; Geller, Aaron M.; Mathieu, Robert D.; Meibom, Soeren; Platais, Imants; Latham, David W.

    2009-01-01

    We present the current results from our ongoing radial-velocity (RV) survey of the intermediate-age (2.4 Gyr) open cluster NGC 6819. Using both newly observed and other available photometry and astrometry, we define a primary target sample of 1454 stars that includes main-sequence, subgiant, giant, and blue straggler stars, spanning a magnitude range of 11 ≤V≤ 16.5 and an approximate mass range of 1.1-1.6 M sun . Our sample covers a 23 arcminute (13 pc) square field of view centered on the cluster. We have measured 6571 radial velocities for an unbiased sample of 1207 stars in the direction of the open cluster NGC 6819, with a single-measurement precision of 0.4 km s -1 for most narrow-lined stars. We use our RV data to calculate membership probabilities for stars with ≥3 measurements, providing the first comprehensive membership study of the cluster core that includes stars from the giant branch through the upper main sequence. We identify 480 cluster members. Additionally, we identify velocity-variable systems, all of which are likely hard binaries that dynamically power the cluster. Using our single cluster members, we find a cluster average RV of 2.34 ± 0.05 km s -1 . We use our kinematic cluster members to construct a cleaned color-magnitude diagram from which we identify rich giant, subgiant, and blue straggler populations and a well defined red clump. The cluster displays a morphology near the cluster turnoff clearly indicative of core convective overshoot. Finally, we discuss a few stars of note, one of which is a short-period red-clump binary that we suggest may be the product of a dynamical encounter.

  17. Remote measurement of surface-water velocity using infrared videography and PIV: a proof-of-concept for Alaskan rivers

    Science.gov (United States)

    Kinzel, Paul J.; Legleiter, Carl; Nelson, Jonathan M.; Conaway, Jeffrey S.

    2017-01-01

    Thermal cameras with high sensitivity to medium and long wavelengths can resolve features at the surface of flowing water arising from turbulent mixing. Images acquired by these cameras can be processed with particle image velocimetry (PIV) to compute surface velocities based on the displacement of thermal features as they advect with the flow. We conducted a series of field measurements to test this methodology for remote sensing of surface velocities in rivers. We positioned an infrared video camera at multiple stations across bridges that spanned five rivers in Alaska. Simultaneous non-contact measurements of surface velocity were collected with a radar gun. In situ velocity profiles were collected with Acoustic Doppler Current Profilers (ADCP). Infrared image time series were collected at a frequency of 10Hz for a one-minute duration at a number of stations spaced across each bridge. Commercial PIV software used a cross-correlation algorithm to calculate pixel displacements between successive frames, which were then scaled to produce surface velocities. A blanking distance below the ADCP prevents a direct measurement of the surface velocity. However, we estimated surface velocity from the ADCP measurements using a program that normalizes each ADCP transect and combines those normalized transects to compute a mean measurement profile. The program can fit a power law to the profile and in so doing provides a velocity index, the ratio between the depth-averaged and surface velocity. For the rivers in this study, the velocity index ranged from 0.82 – 0.92. Average radar and extrapolated ADCP surface velocities were in good agreement with average infrared PIV calculations.

  18. Coefficient of Friction Measurements for Thermoplastics and Fibre Composites Under Low Sliding Velocity and High Pressure

    DEFF Research Database (Denmark)

    Poulios, Konstantinos; Svendsen, Gustav Winther; Hiller, Jochen

    2013-01-01

    that friction materials which are untypical for brake applications, like thermoplastics and fibre composites, can offer superior performance in terms of braking torque, wear resistance and cost than typical brake linings. In this paper coefficient of friction measurements for various thermoplastic and fibre......Friction materials for typical brake applications are normally designed considering thermal stability as the major performance criterion. There are, however, brake applications with very limited sliding velocities, where the generated heat is insignificant. In such cases it is possible...... in order to interpret the changes of friction observed during the running-in phase....

  19. Observations of the radial velocity of the Sun as measured with the novel SONG spectrograph

    DEFF Research Database (Denmark)

    Pallé, P. L.; Grundahl, F.; Hage, A. Triviño

    2013-01-01

    Deployment of the prototype node of the SONG project took place in April 2012 at Observatorio del Teide (Canary Islands). Its key instrument (echelle spectrograph) was installed and operational a few weeks later while its 1 m feeding telescope suffered a considerable delay to meet the required...... specifications. Using a fibre-feed, solar light could be fed to the spectrograph and we carried out a 1-week observing campaign in June 2012 to evaluate its performance for measuring precision radial velocities. In this work we present the first results of this campaign by comparing the sensitivity of the SONG...

  20. On the Flow Measurements and Velocity Vector Analysis Using Five-Hole Pitot Tubes

    OpenAIRE

    NISHIMURA, Hideaki; 西村, 英明

    1981-01-01

    Five-hole pitot tubes are widely used to determine directions and magnitudes of velocities in three-dimensional flow fields, because of their simplicity in handling and their reliability. This paper describes a method of reducing data obtained from five-hole pitot tube measurments with the aid of a few sets of calibration data. By using mini-computers, pitch and yaw angles and Mach numbers of flows can be computed simultaneously by this method with reasonable accuracy in the range of the pito...