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Thesis (Ph. D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (Mar. 1, 2007). Vita. Includes bibliographical references.

Thesis (M.Sc.)--Victoria University of Wellington, 2005. / Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 294-331).

Thesis (Ph. D.)--University of Maryland, 1973. / Includes vita. Includes bibliographical references (leaves 156-163).

The theory of General Relativity has been in existence for 90 years and has stood up to all tests it has been subjected to in that time. The PPN parameter is a measure of the accuracy of theories of gravity and assumes different values in different theories. By measuring the Shapiro time delay of light it is possible to constrain and thereby constrain gravitational theories. This Shapiro time delay can be measured in our solar system but it is only in the vicinity of extremely compact objects such as pulsars and black holes that it can be tested under the immense gravitational fields that can only be found there. A pulsar in a binary orbit about another compact object is the ideal system in which to test this effect. In this work we have gone from Kepler’s laws of simple planetary motion to deriving the equations that explain binary orbits to incorporating General Relativity into these equations in order to obtain the equations for relativistic particle orbits. We then evolved this theory even further so as to be able to explain relativistic light ray orbits and then used this knowledge to model the Shapiro delay in a binary system. With a working model it became possible to simulate the Shapiro delay in a wide range of possible systems and then to use these simulations to say something about what type of system should be focussed on in future so as to measure the Shapiro delay and thereby constrain more tightly the parameter / Dr. C.A. Engelbrecht Dr. F.A.M. Frescura

This dissertation examines two fundamentally different types of isolated systems in general relativity. In part 1, an exact solution of the Einstein-Maxwell equations representing the exterior field of two arbitrary charged essentially spherically symmetric (Reissner-Nordström) bodies in equilibrium is studied. Approximate solutions representing the gravitational- electrostatic balance of two arbitrary point sources in general relativity have led to contradictory arguments in the literature with respect to the condition of balance. Up to the present time, the only known exact solutions which can be interpreted as the nonlinear superposition of two Reissner-Nordström bodies without an intervening strut has been for critically charged masses, [special characters omitted]. In this dissertation . the invariant physical charge for each source is found by direct integration of Maxwell's equations. The physical mass for each source is invariantly defined in a manner similar to which the charge was found. It is shown that balance without tension or strut can occur for non-critically charged bodies. It is demonstrated that other authors have not identified the correct physical parameters for the masses and charges of the sources. Examination of the fundamental parameters of the space-time suggests a refinement of the nomenclature used to describe the physical properties is necessary. Such a refinement is introduced. Further properties of the solution, including the multipole structure and comparison with other parameterizations, are examined. Part 2 investigates the viability of constructing gravitational and electromagnetic geons: zero-rest-mass field concentrations, consisting of gravitational or electromagnetic waves, held together for long periods of time by their gravitational attraction. In contrast to an exact solution, the method studied involves solving the Einstein or Einstein-Maxwell equations for perturbations on a static background metric in a self-consistent manner. The Brill-Hartle gravitational geon construct as a spherical shell of small amplitude, high-frequency gravitational waves is reviewed and critically analyzed. The spherical shell in the proposed Brill-Hartle geon cannot be regarded as an adequate geon construct because it does not meet the regularity conditions required for a non-singular source. An attempt is made to build a non- singular solution to meet the requirements of a gravitational geon. Construction of a geon requires gravitational waves of high-frequency and the field equations are decomposed accordingly. A geon must also possess the property of quasi-stability on a time-scale longer than the period of the comprising waves. It is found that only unstable equilibrium solutions to the gravitational and electromagnetic geon problem exist. A perturbation analysis to test the requirement of quasi-stability resulted in a contradiction. Thus it could not be concluded that either electromagnetic or gravitational geons meet all the requirements for existence. The broader implications of the result are discussed with particular reference to the problem of with particular reference to the problem of gravitational energy. / Graduate

Kwong, Kwok Kun. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 66-70) and index. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Thesis (Ph.D.)--Aberdeen University, 2009. / Title from web page (viewed on Oct. 8, 2009). Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record.