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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 38 for “"sound velocity"”.
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Sound velocity study of natural orthopyroxenes with varying iron content
… system. For each sample and composition, the sound velocities are measured by Brillouin scattering in three orthogonal crystallographic planes. Inverting sound velocity data allows determination of the complete elastic modulus tensor, as well as the adiabatic bulk (Ks) and shear (μs) moduli. …
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Inversion for subbottom sound velocity profiles in the deep and shallow ocean
… in the deep and shallow ocean to infer the sound velocity profile (svp) in the seabed. For the deep water ocean, an exact method based on the Gelfand-Levitan integral equation is evaluated. The input data is the complex plane-wave reflection coefficient estimated from measurements of …
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Inversion for subbottom sound velocity profiles in the deep and shallow ocean
… in the deep and shallow ocean to infer the sound velocity profile (svp) in the seabed. For the deep water ocean, an exact method based on the Gelfand-Levitan integral equation is evaluated. The input data is the complex plane-wave refection coefficient estimated from measurements of acoustic …
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New high pressure phase transition of natural orthoenstatite and sound velocity measurements at simultaneous high pressures and temperatures by laser heating
Studies of phase transformations and sound velocities of candidate mantle minerals under high-pressure high-temperature conditions are essential for understanding the mineralogical composition and physical processes of Earth’s interior. Phase transitions in candidate deep earth minerals under …
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Estimating the upper ocean vertical temperature structure from surface temperature as applied to the southern Benguela
Underwater Sound Velocity Profiles (SVP) are used throughout the world by their respective navies for submarine and surface vessel strategic operations and exercises. Together with the sonar equations, the sound velocity profiles are of paramount importance to solve underwater sound detectability …
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Brillouin studies of diopside and H2O
… curve of Ice VII by simultaneous measurements of sound velocity and angle-dispersive synchrotron x-ray diffraction in a membrane-type diamond anvil cell with resistance heating at elevated temperatures to 873 K at pressures of 2 GPa to 14 GPa. We observed higher melting curves than previous …
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Elastic Constants of Plastic Crystals by Schaefer-Bergmann Scattering: Crystalline Cyclohexane and Deuteromethane
The Schaefer-Bergmann technique for sound velocity measurement has been adapted for use with solidified liquids and gases. The advantages of this method for measuring elastic constants of plastic crystals are discussed. A method for determining both the elastic constants and the spacial orientation …
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Low temperature bulk modulus of solid argon
… of the P=O, T=O bulk modulus obtained from sound velocity measurements shows significant discrepancies. Experimental difficulties in the sound velocity measurements which could account for these discrepancies are discussed. A survey of experimental and theoretical values of the bulk modulus …
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Superfluid helium on solid hydrogen
We measure the third sound velocity of superfluid helium films as functions of temperature and film coverage on H$\sb2,$ D$\sb2,$ and Ar substrates. A new phase of superfluid is discovered on the weak-binding H$\sb2$ substrate. We observe, in addition to third sound, a new surface mode of wave …
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Universal properties of low-temperature glass
… block model to discuss two universal properties: sound velocity/dielectric constant shift, and low-temperature mechanical avalanche problem. We also successfully explain the universal property of glass Meissner-Berret ratio by using our generic coupled block model.
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Density, magnetic properties and sound velocities of iron-rich materials at high temperature and high pressure
… iron-carbon compounds, including the density and sound velocities, with the observed values of inner core, e.g., the values in preliminary reference Earth model (PREM) determined using normal mode data and seismic travel time data. In this work, I studied the density, elasticity, sound velocity …
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Vibrational dynamics in strong glasses: the cases of densified v-SiO2 and v-SiSe2
… sample is a silicon-selenium glass whose low sound velocity allows a detailed study of its dynamics by means of neutron inelastic scattering.
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An Ultrasonic Study of Trapped Hydrogen Tunneling Systems in Niobium and Tantalum
… K for frequencies between 10 MHz and 55 MHz. The sound velocity change due to H in Nb was measured in both the normal and superconducting state at 10.8 MHz and 33 MHz at temperatures between 0.5 K and 18 K. The attenuation and velocity change due to trapped D in Nb was measured in both the …
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THE DYNAMICS OF A TIDAL INTRUSION FRONT IN A NATURAL ESTUARY: EFFECTS ON MULTIBEAM SONAR ACCURACY
… high-resolution measurements of density and velocity to investigate the formation of a transient tidal intrusion front in a narrow, macrotidal estuary, and model the impact of such a frontal system on the accuracy of multibeam sonar surveys. The front was found to form during spring tides, …
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Testing theories for thermal transport using high pressure
… by the pressure dependence of the cross-plane sound velocity, indicating that the cross-plane sound velocity plays an important role in the thermal transport in a layered crystal. The validity of the minimum thermal conductivity model for amorphous polymers was verified by the good agreement …
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Ultrasonic Continuous Wave Spirometer
… system presented in this thesis determines the velocity and temperature fluctuations of the human breath by measuring the difference and sum of the transit times for two continuous sound waves travelling in opposite directions along the air path. The information about the transit times is …
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Phonon thermal transport in metallic glasses below 100 K
… glasses. We also performed variation of sound velocity measurements on a glassy palladium silicon alloy and found qualitative similarity between its behavior and the behavior of nonmetallic glasses. These findings and results from other laboratories have led us to the conclusion that the …
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A study of the effects of lithium perchlorate on poly(ethylene oxide), (Peo) melt dynamic behavior using Fabry-Perot interferometry
… samples revealed a monotonic decrease in the sound velocity and the longitudinal modulus in the medium. The system undergoes a glass transition in this temperature-frequency range. Upon addition of salt the longitudinal modulus increases significantly, which we interpret as stiffening and …
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Sound propagation around underwater seamounts
… and methods which improve the understanding of sound propagation around underwater seamounts. The depth-dependent sound velocity profile of typical ocean waveguides force sound to travel in convergence zones about a minimum sound speed depth. This ducted nature of the ocean makes modeling the …
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Sound propagation around underwater seamounts
… and methods which improve the understanding of sound propagation around underwater seamounts. The depth-dependent sound velocity profile of typical ocean waveguides force sound to travel in convergence zones about a minimum sound speed depth. This ducted nature of the ocean makes modeling the …
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