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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

The synthesis of point data and path data in estimating sofar speed

Johnson, Rockne Hart January 1968 (has links)
Typescript. / Thesis (Ph. D.)--University of Hawaii, 1968. / Bibliography: leaves [31]-32. / v, 32 l maps, graphs

The velocity of second sound near the Lambda point

Johnson, David Lawrence January 1969 (has links)
Direct measurements have been made of the velocity of second sound in liquid helium over the temperature range T[subscript ʎ]-T from 1.3 x 10⁻² K to 5 x 10⁻⁶K. Using previously determined relationships for the specific heat, superfluld density, and thermal conductivity near the lambda point, consistency has been demonstrated between the measurements, velocities predicted by superfluld hydrodynamics, and certain scaling law predictions. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Investigation of a medium with a negative coefficient of nonlinearity

Pinçon, Hervé 05 1900 (has links)
No description available.

Velocity of sound in solid iodine

Leith, Marshall Montgomery January 1966 (has links)
The pulse technique was employed to measure velocities of longitudinal and transverse mechanical waves in solid iodine at ultrasonic frequencies. Pulses were produced and their echoes displayed by a Sperry Ultrasonic Attenuator Comparator. Transducers for generating the waves were: longitudinal waves, X-cut quartz crystals of 5 and 12 Mcs.; transverse waves, Y-cut quartz crystal of. 5 Mcs. For longitudinal measurements the sample was immersed in baths of liquid helium, liquid nitrogen, solid carbon dioxide, ice, ambient room temperature, and boiling water. No dispersion was found. Four samples were used, but as iodine is anisotropic in many of its physical properties most attention was paid to two amorphous samples which were thought to give representative average values of the properties of iodine. From the values of longitudinal velocity, Young's modulus was calculated. Transverse velocity measurements were made in baths of liquid helium, liquid nitrogen, carbon dioxide, and ambient room temperature. The shear, modulus was determined from the transverse velocity; compressibility was found from Young's modulus and the shear modulus. All these quantities behave much as would be expected of a solid material. The Debye characteristic temperature calculated from the longitudinal and transverse velocities was compared with values calculated from specific heat data and Lindemann melting point formula. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

In situ sensing to enable the 2010 thermodynamic equation of seawater

Dakin, Del Thomas 03 January 2017 (has links)
The thermodynamic equation of seawater - 2010 (TEOS-10) is hampered by the inability to measure absolute salinity or density in situ. No new advances for in situ salinity or density measurement have taken place since the adoption of the practical salinity scale in 1978. In this thesis three possible technologies for in situ measurements are developed and assessed: phased conductivity, an in situ density sensor and sound speed sensors. Of these, only sound speed sensors showed the potential for an in situ TEOS-10 measurement solution. To be implemented, sensor response times need to be matched and the sound speed sensor accuracy must be improved. Sound speed sensor accuracy is primarily limited by the calibration reference, pure water. Test results indicate the TEOS-10 sound speed coefficients may also need to be improved. A calibration system to improve sound speed sensor accuracy and verify the TEOS-10 coefficients is discussed. / Graduate / 0415 / 0986 / TDakin@UVic.ca

Responses of hot wire to acoustic excitations

何啓光, Ho, Kai-kwong. January 1980 (has links)
published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

Second sound velocity in helium II

January 1949 (has links)
R.D. Maurer [and] Melvin A. Herlin. / "June 13, 1949." / Bibliography: p. 5. / Army Signal Corps Contract No. W36-039-sc-32037 Project No. 102B. Dept. of the Army Project No. 3-99-10-022.

Laboratory measurements of sound speed and attenuation of water-saturated granular sediments

Argo, Theodore F., 1982- 13 July 2012 (has links)
The propagation of acoustic waves through water-saturated granular sediments has been widely studied, yet existing propagation models can not adequately predict the speed and attenuation of sound across the range of frequencies of interest in underwater acoustics, especially in loosely packed sediments that have been recently disturbed by storms or wave action. Advances in modeling are currently dependent on experimental validation of various components of existing models. To begin to address these deficiencies, three well-controlled laboratory experiments were performed in gravity-settled glass beads and reconstituted sand sediments. Sound speed and attenuation measurements in the 0.5 kHz to 10 kHz range are scarce in the literature, so a resonator method was used to investigate a reconstituted sand sediment in this range. The literature contains laboratory and in situ measurements of sound speed and attenuation at higher frequencies, but existing models can not predict both the speed of sound and attenuation simultaneously in some sediments. A time-of-flight technique was used to determine the speed of sound and attenuation in monodisperse water-saturated glass beads, binary glass bead mixtures, and reconstituted sediment samples in the frequency range 200 kHz to 900 kHz to investigate the effect of sediment inhomogeneity. The effect of porosity, independent of changes in other sediment physical properties, has not been demonstrated in the experimental literature. Therefore, a fluidized bed technique was used to independently vary the porosity of monodisperse glass bead samples from 0.37 to 0.43 and a Fourier phase technique was used to determine the speed and attenuation of sound. Collecting these results together, measured sound speeds showed positive dispersion below 50 kHz while negative dispersion was observed above 200 kHz for some samples. Attenuation measurements showed an approximately f⁰̇⁵ dependence in the low frequency regime and an approximately f³̇⁵ dependence for large-grained samples in the high frequency regime. The laboratory experiments presented in this work demonstrate that both sound speed and attenuation in idealized loosely packed water-saturated sediments can not be simultaneously predicted by existing models within the uncertainties of the model input parameters, but the independent effect of porosity on sound speed can be predicted. / text

Řešení nelineárních hydraulických sítí / Solution of Non-Linear Hydraulic Networks

Himr, Daniel January 2011 (has links)
Thesis deals about solution of non-steady flow in hydraulic systems, which have one dominant component of velocity. Such systems can be arbitrarily structured and they are not limited by number of elements. Computation is based on Lax-Wendroff method and enables considering of variable sound peed as function of static pressure and properties of pipe material. It means, that hydraulic system can be very various. Numerical method is described in detail and description is also focused on sensitivity of method for time step and length step. It can be very imported for evaluation of numerical viscosity, which is compared with second viscosity of fluid. Hammer is working title of software, which was developed on the basis of written numerical procedures. This software enables fast computation of flow in pipe-line systems.

Study on High-Speed Sensing and High-Quality Image Reconstruction for Photoacoustic Biomedical Visualization Technology / 光超音波を用いた医用生体可視化技術における高速センシングと高画質化に関する研究

Cong, Bing 23 July 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(人間健康科学) / 甲第19232号 / 人健博第29号 / 新制||人健||3(附属図書館) / 32231 / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 杉本 直三, 教授 精山 明敏, 教授 戸井 雅和 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

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