Global ETD Search
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 37 for “"Wave Dispersion"”.
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Shock Wave Dispersion in Weakly Ionized Gas
<p>Electrodeless microwave (MW) discharge in two straight, circular cylindrical resonant cavities in TE<sub>1,1,1</sub> and TM<sub>0,1,2</sub> modes were introduced to perform additional experimental studies on shock wave modification in non-equilibrium weakly ionized gases and to clarify the …
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Anomalous Wave Dispersion in the Cyclohexanedione-Bromate Chemical Oscillator
… reaction. The phenomena of anomalous velocity dispersion (in which following waves may catch up to, rather than fall behind an initial excitation wave), wave-stacking, and backfiring have been successfully reproduced numerically as resulting from non-monotonic [Br<super>-</super>] decay to the …
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Anomalous Wave Dispersion in the Cyclohexanedione-Bromate Chemical Oscillator
… reaction. The phenomena of anomalous velocity dispersion (in which following waves may catch up to, rather than fall behind an initial excitation wave), wave-stacking, and backfiring have been successfully reproduced numerically as resulting from non-monotonic [Br<super>-</super>] decay to the …
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Ultrasonic wave dispersion and attenuation as tools for mechanical characterization of construction materials [Dispersione e attenuazione dell'onda ultrasonica come strumenti per la caratterizzazione meccanica dei materiali da costruzione]
Questa tesi di dottorato indaga la dispersione e l’attenuazione delle onde ultrasoniche come strumenti quantitativi per la caratterizzazione meccanica dei materiali da costruzione. Sebbene le tecniche ultrasoniche siano ampiamente utilizzate nella pratica, la loro interpretazione si basa spesso su …
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Seismic site characterization via joint modeling of horizontal-to-vertical spectral ratios and surface wave dispersion : developing and validating a geophysical tool for deciphering Quaternary stratigraphic architecture of the Monahans dune field, West Texas.
… Spectral Ratios (HVSR) and surface wave dispersion offer a cost-effective alternative to deciphering Quaternary architecture, but inverse models are subject to ambiguity and nonuniqueness. We jointly model HVSR and surface wave phase velocity dispersion measurements via global …
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Extracting fluid properties through high-speed video analysis
… video motion analysis using an automated wavelength matching filter followed by fitting of the measurements to theoretical capillary-gravity wave dispersion equations. This method requires an understanding of how field of view, refraction, and parallax affect measurements. We tested the …
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Development of the Spectral-Analysis-of-Body-Waves (SABW) method for downhole seismic testing with boreholes or penetrometers
… been used to calculate shear and compression wave velocities in soil and rock layers. This time-domain method requires an operator to pick the first arrival or other reference point of each seismic wave in the time record. Picking these reference points correctly is critical in calculating …
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Seismic site characterization through joint modeling of complementary data functionals, with applications to Santo Domingo, Dominican Republic.
… to vertical spectral ratios (HVSR) and surface wave dispersion, performed via refraction microtremor (ReMi). Fitting of data functionals by synthetics is driven by global optimization. The products of this approach are shear wave velocity profiles for the subsurface, accompanied by marginal …
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Development of Deep Site Specific and Reference Shear Wave Velocity Profiles in the Canterbury Plains, New Zealand
<p>Deep (typically >1000 m) shear wave velocity profiles were developed across the Canterbury basin at nine strong motion stations using a combination of active and passive surface wave methods and horizontal to vertical spectral ratio measurements. A multi-mode, multi-method joint inversion …
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Velocity and anisotropy structure of the Icelandic crust - An ambient seismic noise analysis
Measuring the travel times of seismic waves is one of the most important tools for uncovering Earth’s structure and dynamics. In recent years, the discovery that surface wave dispersion could be estimated from ambient noise has introduced new possibilities into the field of seismic imaging, such as …
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Advanced analysis of complex seismic waveforms to characterize the subsurface Earth structure
This thesis includes three major parts, (1) Body wave analysis of mantle structure under the Calabria slab, (2) Spatial Average Coherency (SPAC) analysis of microtremor to characterize the subsurface structure in urban areas, and (3) Surface wave dispersion inversion for shear wave velocity …
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Whistler Waves: Modeling and Observations
… Research [1]. This research focuses on whistler wave ducting events in the equatorial magnetosphere. High-density ducts are the main focus of whistler study in both studies as they are commonly observed by the Van Allen Probe satellites. A three-step procedure based on the analysis of the …
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Applications of time series analysis to geophysical data
… series analysis to geophysical data. Surface wave dispersion along the Walvis Ridge, South Atlantic Ocean, is obtained by bandpass filtering the recorded seismogram in the frequency domain. The group velocity is anomalously low in the period range of 15-50 s, and formal inversion of the data …
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The Automation of Numerical Models of Coseismic Tsunamis
… in the short term, often requiring seismic waveform inversion, which takes a length of time on the order of weeks to months to properly model, and is much too late for any use in a now-casting sense. To expedite this length of time, a series of source models are created with variable fault …
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Ultracold quantum gases in one-dimensional optical lattice potentials : nonlinear matter wave dynamics
… on experiments on the quantum dynamics of matter waves in a onedimensional lattice potential. A 87Rb Bose-Einstein condensates is prepared in a one-dimensional waveguide in the lowest band of a superimposed optical lattice potential. The action of a weak lattice potential allows to modify the …
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S-wave velocity structure beneath the Kaapvaal Craton from surface-wave inversions compared with estimates from mantle xenoliths
Results from two-station surface-wave inversions across the Archean Kaapvaal craton of southern Africa are compared with seismic velocities estimated from approximately 100 mantle xenoliths brought to the surface in kimberlite pipes. As the xenoliths represent a snapshot of the mantle at the time …
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Nonlinear dynamics of three-dimensional solitary waves
In problems of dispersive wave propagation governed by two distinct restoring-force mechanisms, the phase speed of linear sinusoidal wavetrains may feature a minimum, cmin, at non-zero wavenumber, kmin. Examples include waves on the surface of a liquid in the presence of both gravity and surface …
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Surface Wave Propagation and Global Crustal Tomography
… calculate Born sensitivity kernels for Rayleigh-wave phase and amplitude measurements that are valid in regions near seismic stations. Calculations of sensitivity kernels for inter-station measurements show that exact travelling-wave representation of Green tensor is necessary when station …
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