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 207 for “"Plane wave"”.
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Asmptotically Plane Wave Spacetimes
In this thesis we study aspects of plane wave spacetimes in the hope of shedding light of the nature of holography for plane waves. In particular, we would like to understand better the space of asymptotically plane wave solutions. We first review the necessary background on plane waves, …
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Optimization of Plane Wave Directions in Plane Wave Discontinuous Galerkin Methods for the Helmholtz Equation
… In particular, for the 2D Helmholtz equation, plane waves have been used to derive an Interior Penalty (IP) type Plane Wave DG (PWDG) method and to provide an a priori error analysis of its p-version with respect to equidistributed plane wave directions. However, the dependence on the …
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Plane Wave Sound Radiation From Mobile Dislocation Walls
Made available in DSpace on 2015-05-12T21:41:51Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 6915382.PDF: 3884868 bytes, checksum: 4baa7a010e5500aeecb6ad207c909954 (MD5) Previous issue date: 1969
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Efficient seismic imaging with the double plane wave data
… time migration (RTM), which solves the two-way wave equation, can resolve all wavefield propagation phenomena. In geologically complex regions, RTM has been proven to outperform other imaging methods in correctly revealing the subsurface structures. However, implementing the traditional …
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Fast Inhomogeneous Plane Wave Algorithm for Electromagnetic Scattering Problems
The fast inhomogeneous plane wave algorithm (FIPWA) has been developed and successfully applied to solving large-scale electromagnetic scattering problems, both in free space and in the presence of a multilayered medium. A multilevel program has been implemented. The resultant computational …
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Finite Element Study of Plane Wave Acoustic Phenomena in Ducts
… thesis studied the finite element modeling of plane wave acoustic phenomena in ducts. The study looked into finite element factors such as shape functions, mesh refinement, and element distortion. The study concluded that the higher order shape function eight-node quadrilateral element gave …
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Derivation of Moving-Coil Loudspeaker Parameters Using Plane Wave Tube Techniques
… domain will be developed. The technique uses a plane wave tube to measure acoustical properties of a baffled driver under test. Quantities such as the transmission loss through the driver are measured for a driver placed in the tube using the two-microphone transfer-function technique. Models …
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Wave tailoring granular materials: effect of randomness and plane wave propagation
… in material and geometric properties on wave propagation behavior in 1D and 2D granular media. Results obtained for both 1D chains and 2D media show the kinetic energy amplitude decays with distance, with the rate of decay found to depend on the level of randomness and the distance from …
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Plane Wave Diffraction by Thick Dielectric Gratings, and Zone Phase Plates
Made available in DSpace on 2014-12-08T22:23:37Z (GMT). No. of bitstreams: 1 6500910.pdf: 4201347 bytes, checksum: 06f022c75dc4e7876e20e128ffdc286e (MD5) Previous issue date: 1964
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Electromagnetic plane wave scattering from periodically loaded cylinders and doubly periodic slabs
Periodic structures are of great importance in the design of antenna and radome systems, and also find many applications in the area of low observability. In this thesis, two important geometries are investigated, namely, structures which are periodic along one axis and finite along the other two …
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Determining distributed source waveforms in casual, lossy, dispersive, plane-wave (CLDP) materials
… response signal, a space z dependent source waveform, and a kernel with time dependence (at each z) corresponding to the impulse response of a thickness z slab of causal, lossy, dispersive, homogeneous material through which planar disturbances propagate according to the wave equation. These …
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Multiple plane wave analysis of acousto-optic diffraction of Gaussian shaped light beams
A short history of acousto-optics research is presented along with a general description of how light and sound interact. The Multiple Scattering model is derived and used with a Gaussian light beam to observe the distortion in light beam profile within the sound field. Numerical results are …
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Algorithm for computation of the acoustic plane-wave reflection coefficient of the ocean bottom
For a spherical acoustic wave incident on a horizontally stratified ocean bottom, the reflected pressure field and the plane-wave reflection coefficient are related through a two-dimensional spatial-wavenumber Fourier transform. An algorithm is proposed to evaluate the plane-wave reflection …
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Plane -Wave Time -Domain Algorithms for Efficient Analysis of Three-Dimensional Transient Wave Phenomena
Computer simulation of linear transient wave phenomena involving structures that reside in an unbounded medium to generate broadband data is of paramount importance in such disciplines as acoustics, electromagnetics, and geophysics. Numerical techniques to perform such simulations call for the …
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Band structure of silver chloride and silver bromide by the augmented plane wave method
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 1964
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Plane wave parameter estimation using gps estimates of total electron content in a neural network
… such as tsunamis, have been shown to create wave features in the free electron density. The parameterization of these waves is of interest to the scientific community. Here, we investigate the application of neural networks as our parameter estimator. In this study, we provide a background on …
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New full wave theory for plane wave scattering by a rough dielectric surface - the fictitious current method
A new full wave method for scattering of plane waves from a rough dielectric surface is developed. This new theory begins by postulating a zero-order field solution which does not satisfy Maxwell's source-free field equations. The zero-order field, however, is made to satisfy Maxwell's source …
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The Plane Wave Born Approximation for Determining Atomic K-Shell Ionization Cross- Sections by Positive Ion Impact
… development in this work is based upon the plane wave Born approximation (PWBA) as worked out by Merzbacher and his co-workers (Me58, Me73). In Chapter III, Merzbacher's development of the theory is presented as is found in (Me58), but with many of the missing steps worked out in detail. In …
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Application of Complex Ray Tracing to the Scattering of an Evanescent Plane Wave by a Conducting Circular Cylinder
Made available in DSpace on 2014-12-10T19:07:27Z (GMT). No. of bitstreams: 1 7511700.pdf: 2058102 bytes, checksum: b4c7793a1ac3a952979a3deb3c014544 (MD5) Previous issue date: 1974
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The numerical synthesis and inversion of acoustic fields using the Hankel transform with application to the estimation of the plane wave reflection coefficient of the ocean bottom
The plane wave reflection coefficient is an important geometry independent mean of specifying the acoustic response of a horizontally stratified ocean bottom. It is an integral step in the inversion of acoustic field measurements to obtain parameters of the bottom and it is used to characterize an …
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