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Sedimentary lipids as indicators of depositional conditions in the coastal Peruvian upwelling regimeMcCaffrey, Mark A January 1990 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, and Woods Hole Oceanographic Institution, 1990. / Vita. / Includes bibliographical references. Includes bibliographical references. / by Mark A. McCaffrey. / Ph.D.
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Initial data for axially symmetric black holes with distorted apparent horizonsTonita, Aaryn 05 1900 (has links)
The production of axisymmetric initial data for distorted black holes at a moment
of time symmetry is considered within the (3+1) context of general relativity. The
initial data is made to contain a distorted marginally trapped surface ensuring that,
modulo cosmic censorship, the spacetime will contain a black hole. The resulting
equations on the complicated domain are solved using the piecewise linear finite element method which adapts to the curved surface of the marginally trapped surface.
The initial data is then analyzed to calculate the mass of the space time as
well as an upper bound on the fraction of the total energy available for radiation.
The families of initial data considered contain no more than few percent of the
total energy available for radiation even in cases of extreme distortion. It is shown
that the mass of certain initial data slices depend to first order on the area of the
marginally trapped surface and the gaussian curvature of prominent features.
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Independent set problems and odd-hole-preserving graph reductionsWarren, Jeffrey Scott 15 May 2009 (has links)
Methods are described that implement a branch-and-price decomposition
approach to solve the maximum weight independent set (MWIS) problem. The
approach is first described by Warrier et. al, and herein our contributions to this
research are presented. The decomposition calls for the exact solution of the
MWIS problem on induced subgraphs of the original graph. The focus of our
contribution is the use of chordal graphs as the induced subgraphs in this solution
framework.
Three combinatorial branch-and-bound solvers for the MWIS problem are
described. All use weighted clique covers to generate upper bounds, and all
branch according to the method of Balas and Yu. One extends and speeds up
the method of Babel. A second one modifies a method of Balas and Xue to
produce clique covers that share structural similarities with those produced by
Babel. Each of these improves on its predecessor. A third solver is a hybrid of
the other two. It yields the best known results on some graphs.
The related matter of deciding the imperfection or perfection of a graph
is also addressed. With the advent of the Strong Perfect Graph Theorem, this
problem is reduced to the detection of odd holes and anti-holes or the proof of
their absence. Techniques are provided that, for a given graph, find subgraphs in
polynomial time that contain odd holes whenever they are present in the given graph. These techniques and some basic structural results on such subgraphs
narrow the search for odd holes.
Results are reported for the performance of the three new solvers for the
MWIS problem that demonstrate that the third, hybrid solver outperforms its
clique-cover-based ancestors and, in some cases, the best current open-source
solver. The techniques for narrowing the search for odd holes are shown to
provide a polynomial-time reduction in the size of the input required to decide
the perfection or imperfection of a graph.
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Anti-de Sitter black holes in supergravityChong, Zhiwei 02 June 2009 (has links)
In this dissertation, we systematically construct non-extremal charged rotating
anti-de Sitter black hole solutions in four, five and seven dimensions. In four dimensions,
we first obtain the rotating Kerr-Taub-NUT metric with four independent
charges, as solutions of N = 2 supergravity coupled to three abelian vector multiplets
by the solution generating technique. Then we generalise the four-dimensional rotating
solutions to the solutions of gauged N = 4 supergravity with charges set pairwise
equal. In five dimensions, the most general charged rotating black hole solution has
three charge and two rotation parameters. We obtain several special cases of the general
solution. To be specific, we obtain the first example of a non-extremal rotating
black hole solution with two independent rotation parameters, which has two charge
parameters set equal and the third vanishing. In another example, we obtain the nonextremal
charged rotating black hole solution with three charge parameters set equal
and non-equal rotation parameters. We are also able to construct the single-charge
solution with two independent rotation parameters. In seven dimensions, we obtain
the solution for non-extremal charged rotating black holes in gauged supergravity, in
the case where the three rotation parameters are set equal. There are two independent
charges, corresponding to gauge fields in the U(1) × U(1) abelian subgroup of
the SO(5) gauge group.
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Cosmological environment study of a black hole : A closer look on the science of InterstellarGustafsson, Anton January 2015 (has links)
This report looks closer on the physics of black holes and their related phenomena. Particularly, this report studies a certain black hole called Gargantua that is portrayed in the movie Interstellar. By using this as a source of inspiration we look at Gargantua’s effect on time, planetary orbits and tidalforces. The following report showed that the physics studied here corresponded fully to the physics represented in Interstellar, making the movie very credible from a physics point of view. I show that the black hole portrayed in Interstellar needed to spin at a rate of 1.33*10^-14 percent less than its maximum possible to achieve a timedilation of 61320 at the distance where stable planetary orbits are found. At a spin this high, planets can have stable orbits as close as half the Schwarzschild radius which means they are located just outside the event horizon of a maximally rotating black hole. The enormous timedilation at planets orbiting near the event horizon is a result of the planets close proximity to the black hole, its orbital velocity and frame dragging. Frame dragging describes the effects on spacetime on account of the rotation of the black hole. Looking at the tidal forces on objects surrounding the black hole it was found that an increasing mass would actually decrease the tidal forces on objects outside the event horizon. For a sufficiently large mass on the black hole, a planet could avoid being ripped apart but this restricted its size to a radial extension of about 5500 km which corresponds to 0.86 earth radiuses.
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Initial data for axially symmetric black holes with distorted apparent horizonsTonita, Aaryn 05 1900 (has links)
The production of axisymmetric initial data for distorted black holes at a moment
of time symmetry is considered within the (3+1) context of general relativity. The
initial data is made to contain a distorted marginally trapped surface ensuring that,
modulo cosmic censorship, the spacetime will contain a black hole. The resulting
equations on the complicated domain are solved using the piecewise linear finite element method which adapts to the curved surface of the marginally trapped surface.
The initial data is then analyzed to calculate the mass of the space time as
well as an upper bound on the fraction of the total energy available for radiation.
The families of initial data considered contain no more than few percent of the
total energy available for radiation even in cases of extreme distortion. It is shown
that the mass of certain initial data slices depend to first order on the area of the
marginally trapped surface and the gaussian curvature of prominent features.
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Initial data for axially symmetric black holes with distorted apparent horizonsTonita, Aaryn 05 1900 (has links)
The production of axisymmetric initial data for distorted black holes at a moment
of time symmetry is considered within the (3+1) context of general relativity. The
initial data is made to contain a distorted marginally trapped surface ensuring that,
modulo cosmic censorship, the spacetime will contain a black hole. The resulting
equations on the complicated domain are solved using the piecewise linear finite element method which adapts to the curved surface of the marginally trapped surface.
The initial data is then analyzed to calculate the mass of the space time as
well as an upper bound on the fraction of the total energy available for radiation.
The families of initial data considered contain no more than few percent of the
total energy available for radiation even in cases of extreme distortion. It is shown
that the mass of certain initial data slices depend to first order on the area of the
marginally trapped surface and the gaussian curvature of prominent features. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
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Mass, heat, oxygen and nutrient fluxes at 30s̊ and their implications for the Pacific-Indian through flow and the global heat budgetMacdonald, Alison Marguerite January 1991 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1991. / Includes bibliographical references (p. 177-183). / by Alison Marguerite Macdonald. / M.S.
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Variations in structure and tectonics along the Mid-Atlantic Ridge, 23NÌŠ and 26NÌŠ by Laura Sau Lin Kong.Kong, Laura S. L January 1990 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1990. / Includes bibliographical references. / Ph.D.
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Meridional circulation in the tropical North AtlanticFriedrichs, Marjorie Anne MacWhorter January 1992 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1992. / Includes bibliographical references (p. 49-52). / by Marjorie Anne MacWhorter Friedrichs. / M.S.
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