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 34 for “"Wave structure"”.
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Theory of optical rectification in a travelling wave structure
… is concerned with the interaction of an optical wave with a microwave in a waveguiding structure coupled by a second order nonlinearity. Emphasis is laid upon the generation of ultrashort electrical transients via optical rectification (OR) as well as cascading effects due to the interplay of OR …
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Water wave-structure interaction for small amplitude structural oscillations
The water wave/structure interaction is a complex phenomenon, which affects the prediction of the dynamic response of offshore structures. The problem arises from the interdependence of the structural response and the wave force. This interdependence is usually represented by the effect of the …
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The Wave Structure Function And Temporal Frequency Spread In Weak To Strong Optical Turbulence
This paper presents analytic expressions for the wave structure function, frequency spread of the temporal frequency spectrum, and the temporal frequency spectrum of optical signals propagating through a random medium, specifically the Earth’s atmosphere. The results are believed to be valid for …
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Utilization of a tropospheric-stratospheric lidar system to study mountain induced gravity waves over jenny jump state forest
Gravity waves are a dominant driver of the middle and lower atmospheric circulation. Yet such waves have been difficult to study due to their inherent small spatial and temporal scales and synoptic occurrence, and thus require advanced experimental systems. In this thesis first results are …
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Estimation of Intrinsic Gravity Wave Parameters From Multiple, Ground-Based Observations of a Single Mesopheric Airglow Emission
… key intrinsic parameters of atmospheric gravity waves (AGWs). As AGWs propagate through the mesosphere, they spatially and temporally perturb mesospheric airglow emissions, which, from the ground, can be imaged using large-format CCD cameras retrofitted with spectroscopic optics. By observing the …
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An experimental investigation of the forebody of a hypersonic inlet model and a comparison with theory
… streamlines on the wedge surfaces and the shock waves from the wedge leading edges. The data was obtained from surface static pressure taps, pitot probe surveys, oil-streak tests, and schlieren photographs. The results of the investigation indicate that the leading-edge shock waves join in a …
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High linearity broad-band helix TWTs
Helix travelling-wave tubes (TWTs) are extensively employed as final power amplifiers in satellites. These applications demand low spectral noise and high efficiency across a broad band. Research has been carried out to achieve these criteria in a helix TWT design. A deeper understanding has been …
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Microwave emission in a plasma filled nonuniform backward wave oscillator
High power microwave radiation is used in science, industry, and by the military for a variety of purposes including the acceleration of particles in high energy physics, heating of plasma particles, radiation treatment of surfaces in manufacturing, and for electronic warfare in the military. Among …
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The vertical structure of stratospheric planetary waves and its variability : theory and observations
Observations of the vertical structure of stratospheric planetary waves reveal a large variety of structures, and a variability both on seasonal and on daily time scales. The extent to which linear wave theory explains these structures and their time evolution at a given time or season is not well …
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Three pion production on complex nuclei at 23 GeV/c
… analyzed using the Illinois method of partial wave analysis. The partial wave structure of the data is remarkably similar to that of the data from hydrogen, excepting the distributions in momentum transfer, which exhibit the usual coherent and incoherent contributions of nuclear scattering. The …
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Time-domain second-order wave interactions with floating offshore structures
… past decade, numerical modelling of nonlinear wave-structure interaction problems has been an important topic of ocean engineering research, with practical applications relating to load and response predictions for large floating structures subjected to steep waves. With the increasing need to …
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Theory of Detonation Structure for Two-Phase Materials
The structure of a two-phase steady detonation in a granulated solid propellant has been studied, and existence conditions for a one-dimensional, steady two-phase detonation have been predicted. Ordinary differential equations from continuum mixture theory have been solved numerically to determine …
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Blast overpressure relief using air vacated buffer medium
Blast waves generated by intense explosions cause damage to structures and human injury. In this thesis, a strategy is investigated for relief of blast overpressure resulting from explosions in air. The strategy is based on incorporating a layer of low pressure-low density air in between the blast …
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Improvements in the numerical modelling of wake effects for wave energy converter farms
… estimated that 100 GW of ocean energy capacity (wave and tidal) could be deployed in Europe by 2050. Along with these European targets it is expected that large farms of Wave Energy Converters (WECs) will be installed in the sea and as part of the consenting process it will be necessary to …
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Solid-state microwave amplification into millimetric frequencies
… of the thermal operation of the diode, the microwave circuit design required for the class - C reflection amplifier operation and an in depth analysis of the technical problems associated with the design of high-frequency TRAP A IT circuits, which final led to the decline of the technology at …
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Hydrodynamic modelling of the oscillating wave surge converter
… the numerical modelling of the Oscillating Wave Surge Converter (OWSC). The OWSC is a bottom hinged, flap-type, pitching wave energy converter. The device is installed in shallow water (10 - 15 metres} and covers the entire water column from the sea floor to the water surface. Its motion is …
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Influence of Fuel Inhomogeneity and Stratification Length Scales on Detonation Wave Propagation in a Rotating Detonation Combustor (RDC)
… (RDC) is a form of PGC, in which the detonation wave propagates azimuthally around an annular combustor. Prior researchers have performed a high fidelity 3-D numerical simulation of a rotating detonation combustor (RDC) to understand the flow physics such as detonation wave velocity, pressure …
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Numerical Modelling of Breaking Waves under the Influence of Wind
Wave breaking plays an important role in air-sea interaction, surf zone dynamics, nearshore sediment transport, marine hydrodynamics, and wave-structure interaction. When the wind is blowing over water waves, it not only enhances the exchanges of heat, mass and momentum on the air-water interface, …
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Configurable multi-port radiators
… of the radiators that overcome the need for full-wave design and simulation of the apertures. As a proof of concept, we developed some large-scale multi-port antenna prototypes with the ability to adjust their center frequency while synthesizing a desired far-field pattern only by modulating the …
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