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Showing 1 to 20 of 26 for “"Caustics"”.
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Caustics in gravitational theories
The gravitational collapse of a spherically symmetric, pressure-free dust is an interesting problem in General Relativity for it can lead, under certain initial conditions, to the situation where infinitesimally neighbouring shells approach and cross each other. The curve generated by these points …
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Understanding dark matter halos with tidal caustics
… objects motivates us to name them "tidal caustics". We study the densities achievable in tidal caustics for a typical merger of this type using an example from the Andromeda galaxy to determine whether they are sufficient to produce a detectable gamma-ray signal from self-interactions in …
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Caustics and evolutes for convex planar domains
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1986.
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HALO : re-forming architectural space with light caustics
What form can light take? Light has been an eternal theme in architectural design. Light defines, shapes, and transforms space in various ways. However, the way light has been used in human history has not changed: the variation of space is a result of the interaction between light and shadow along …
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Computer simulations to calculate energy flux and image size on a receiver for different reflector geometries using caustics
Increasing energy demands due to growing population, climate change, the depletion of fossil fuels and the toxic effects of combustion by products are all pushing towards the energy production via renewable energy sources. Most of the countries that lie on the ‘‘Sun Belt’’, where solar irradiation …
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Dynamic lighting and its impact on the behaviour of marine invertebrates
… comes from a form of dynamic lighting known as caustics, where refraction of light through surface waves creates fluctuations in the light intensity as well as false motion cues in the visual scene. While caustics impair the visual systems of teleost fishes, whether they impact other aquatic …
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Applications of the Optical Method of Caustics to the Study of Viscoelastic Dynamic Fracture and Static Blunt Crack Fronts
… in the optical methods of photoelasticity and caustics, are extended to linearly viscoelastic materials. The Maxwell-Neumann relation for the stress-optic constants, which is good for linearly elastic behavior, is replaced by an expression derived from the Clausius-Mosotti-Lorentz-Lorenz (CMLL) …
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Semiclassical asymptotics for the scattering amplitude in the presence of focal points at infinity
… in the presence of focal points at infinity (caustics). Crucial for this analysis are precise estimates on the asymptotics of the classical phase trajectories and the relationship between caustics in euclidean phase space and caustics at infinity.
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Some Aspects of the Mechanics and Mechanisms of Dynamic Brittle Fracture
… high-speed photography, as used in the method of caustics, and in dynamic photoelasticity.
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Micro-images of macro-lensed objects
… used approximation for magnifications near fold caustics. Our results show that the approximation is noticeably broken at a caustic strength-scaled distance of 0.1. The relevance of this breakdown to work done by other authors is briefly examined. We then then discuss a few new results for the …
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Study of phonon transmission through solid-solid interfaces and superlattices by phonon imaging
… developed whereby the pattern of phonon-focusing caustics may be predicted for any cubic material given its elastic constants and density. 2. Heat-pulse propagation across a copper-diamond interface. Phonon imaging experiments in diamond reveal sharp structures in addition to phonon-focusing …
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General linear cameras : theory and applications
… system, and they are closely related to the caustics of reflected rays. These geometric structures are characteristic of only 4 of the 8 GLC types. I also prove that the local GLC type at each tangent plane is invariant to the choice of parametrization, and, thus, an intrinsic property of the …
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Vector occluders: an empirical approximation for rendering global illumination effects in real-time
… global illumination effects including shadows, caustics and interreflections to a locally illuminated scene on static geometry. VO encodes PRT data as simple vectors instead of using SH. VO can handle point lights, whereas a standard SH implementation cannot.
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A wave-kinetic numerical method for the propagation of optical waves
… and the propagation of optical waves through caustics or ray crossings. The numerical results agree well with either the Monte-Carlo method or the first Born approximation in regions where one or both of these are expected to be valid.
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ΕΠΙΔΡΑΣΗ ΤΗΣ ΠΑΡΟΥΣΙΑΣ ΡΩΓΜΩΝ ΣΤΗΝ ΚΑΤΑΝΟΜΗ ΤΗΣ ΕΝΤΑΣΕΩΣ ΣΕ ΘΛΙΒΟΜΕΝΑ ΣΩΜΑΤΑ. ΕΦΑΡΜΟΓΕΣ ΣΤΗΝ ΠΕΡΙΟΧΗ ΤΗΣ ΒΡΑΧΟΜΗΧΑΝΙΚΗΣ
… THE TIPS OF THE PROPAGATED CRACKS, THE METHOD OF CAUSTICS HAS BEEN USED. THE METHOD WAS PREVIOUSLY TESTED IN A SERIES OF EXPERIMENTS ON MODELS WITH CRACKS AND SLITS UNDER COMPRESSION. THE EXPERIMENTAL RESULTS WERE IN AGREEMENT WITH THE ASSUMPTIONS MADE IN THE THEORETICAL PART OF THE DISSERTATION.
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Scattering of an ultrasonic beam from a curved interface
… Of particular interest is the formation of caustics and cusps by the reflected and transmitted rectangular beam when it is scattered by the concave interface. Also of particular interest is the propagation and radiation into the fluid of the Rayleigh wave excited on the convex interface.
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Differential algebraic methods for obtaining approximate numerical solutions to the Hamilton-Jacobi equation
… the generating function becomes singular near caustics or foci. One may continue integrating through a caustic by using a Legendre transformation to obtain a new (but equivalent) generating function which is singular near the identity, but nonsingular near the caustic. However the Legendre …
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Alkylation of phenol with methanol over H-ZSM-5, H-Beta, H-Mordenite, H-USY and H-MCM-22
… cresols obtained from coal tars and refinery caustics. The methylation of phenol is the only process specifically developed to produce cresols and xylenols. There are three cresol isomers, namely ortho, para and meta. It is possible to produce a high selectivity to o-cresol by alkylation of …
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Scalable parallel simulation of small-scale structures in cold dark matter
… z > 50. We observe and analyze the formation of caustics in the structure and compare it with the predictions of semi-analytic models of structure formation. The current limits on neutralino detection experiments assume a Maxwell-Boltzmann velocity distribution and smooth spatial distribution of …
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Probabilistic Roadmaps for Virtual Camera Pathing with Cinematographic Principles
… underwater elements such as rocks, bubbles and caustics. The digital shipwreck model was reconstructed from an actual World War II shipwreck, resting off the coast of Malta. Video and sonar scans from an autonomous underwater vehicle were used in a photogrammetry pipeline to create the …
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