Um Detector de Ondas Gravitacionais tipo Massa-Ressonante Esférico é otimizado. Primeiramente um modelo matemático para o detector com seis transdulatores indutivos supercondutivos de dois modos é usado para simular o desempenho de tal detector. Depois disso, um conjunto completo de experimentos para melhorar os fatores de qualidade mecânico e elétrico do transdutor e dos acoplamentos entre suas partes é mostrado e os resultados, discutidos. / A Spherical Resonant-Mass Detector of Gravitational Waves is optimized. First, a mathematical model for the detector with six inductive superconducting two-mode transducers is used to simulate the performance of such detector. After that, a complete set of experiments to improve the mechanical and the electrical quality factors of the materials and the transducer attachments is shown, and the results are discussed.

No description available.

Lau, Hoi Kwan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 208-212). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Gravitational wave astronomy --- p.1 / Chapter 1.2 --- Stellar pulsation and gravitational radiation --- p.3 / Chapter 1.3 --- Outline --- p.5 / Chapter 2 --- Hydrostatic stellar structure --- p.8 / Chapter 2.1 --- Structural equation --- p.9 / Chapter 3 --- Finite temperature equations of state of nuclear matter --- p.13 / Chapter 3.1 --- Finite temperature ordinary nuclear matter --- p.13 / Chapter 3.2 --- Strange Quark Matter --- p.15 / Chapter 3.3 --- Equilibrium and Dynamic EOS --- p.16 / Chapter 4 --- Stellar pulsation and gravitational radiation --- p.19 / Chapter 4.1 --- Linearized theory of general relativity --- p.19 / Chapter 4.2 --- Stellar oscillation --- p.25 / Chapter 4.3 --- Quasi-normal Mode --- p.28 / Chapter 4.3.1 --- f mode --- p.29 / Chapter 4.3.2 --- p mode --- p.29 / Chapter 4.3.3 --- g mode --- p.30 / Chapter 4.3.4 --- w mode --- p.31 / Chapter 5 --- Gravitational wave spectrum of hot compact stars --- p.32 / Chapter 5.1 --- Numerical results --- p.32 / Chapter 5.1.1 --- Temperature effect on QNM --- p.32 / Chapter 5.1.2 --- Temperature effect and QS model --- p.38 / Chapter 5.1.3 --- QNM shift due to phase transition --- p.41 / Chapter 5.2 --- Summary and prospective --- p.48 / Chapter 6 --- Universality of fundamental mode and spacetime mode --- p.50 / Chapter 6.1 --- Review --- p.50 / Chapter 6.2 --- Generic proposal of universalities --- p.53 / Chapter 6.2.1 --- Moment of Inertia --- p.54 / Chapter 6.2.2 --- Gravitational wave spectrum --- p.57 / Chapter 6.3 --- Universality on moment of inertia --- p.63 / Chapter 6.4 --- Origin of universality --- p.70 / Chapter 6.4.1 --- Tolman VII model --- p.71 / Chapter 6.4.2 --- Polytropic Model --- p.76 / Chapter 6.5 --- Application of universality --- p.82 / Chapter 6.6 --- Summary --- p.89 / Chapter 7 --- Quark star properties and gravity mode oscillation --- p.92 / Chapter 7.1 --- Introduction --- p.92 / Chapter 7.2 --- g mode frequencies of quark stars --- p.94 / Chapter 7.2.1 --- Temperature profile and p mode frequency --- p.96 / Chapter 7.2.2 --- Strange quark mass and Yp mode frequency --- p.104 / Chapter 7.3 --- Summary --- p.108 / Chapter 8 --- Gravitational radiation excitation by infalling shell --- p.111 / Chapter 8.1 --- Introduction --- p.111 / Chapter 8.2 --- Formalism --- p.116 / Chapter 8.2.1 --- Connection between star and vacuum --- p.117 / Chapter 8.2.2 --- Matter source --- p.121 / Chapter 8.2.3 --- Geodesic --- p.124 / Chapter 8.2.4 --- Source of infalling dust shell --- p.126 / Chapter 8.2.5 --- Green's function --- p.127 / Chapter 8.3 --- Gravitational Wave excitation by collapsing shell --- p.130 / Chapter 8.4 --- Features of radiation --- p.138 / Chapter 8.4.1 --- Power spectrum --- p.138 / Chapter 8.4.2 --- Wave function --- p.144 / Chapter 8.4.3 --- Energy of excitation --- p.147 / Chapter 8.5 --- Non-adiabatic oscillation --- p.153 / Chapter 8.5.1 --- Mathematical Background --- p.154 / Chapter 8.5.2 --- Numerical results --- p.158 / Chapter 8.6 --- General relativistic simulation --- p.163 / Chapter 8.6.1 --- Technical briefing --- p.163 / Chapter 8.6.2 --- Numerical results --- p.166 / Chapter 8.7 --- Summary --- p.174 / Chapter 9 --- Conclusion and remarks --- p.178 / Chapter A --- Unit conversions --- p.183 / Chapter B --- Series expansion of quark star EOS --- p.185 / Chapter C --- Accuracy of simplified mode extraction scheme --- p.188 / Chapter D --- Computation of moment of inertia --- p.193 / Chapter E --- Comment of exactness of inference scheme --- p.195 / Chapter E.1 --- Precision of the mass inferred --- p.195 / Chapter E.2 --- Accuracy of universality combinations --- p.199 / Chapter F --- Calculation of sound speed --- p.202 / Chapter G --- Mode extraction of non-adiabatic oscillation --- p.204 / Bibliography --- p.208

Thesis (Ph. D.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 113-116). Also available for download via the World Wide Web; free to University of Oregon users.

Gravitational waves are predicted by Einstein’s general theory of relativity and have so far only been indirectly detected. The first direct detection should however only be a matter of time, with observatories across the world working hard to detect them. Once gravitational waves are detected they are predicted to be very useful in the field of astronomy. In order to be able to successfully interpret measurements from gravitational waves we need to have knowledge of how the wave is affected by its medium of propagation. Because of that, the purpose of this thesis is to investigate the behaviour of gravitational waves in the medium of a magnetised plasma. Using a kinetic plasma model, Einstein’s field equations and tetrad formalism, a general solution for a gravitational wave propagating in the medium is derived. The general solution is then used to find the dispersion relation of the gravitational wave for two special cases: the case of Alfvén resonance and the case of cyclotron resonance. The Alfvén case is already studied in the literature and is found to match the previous results saying it will not affect the wave much. The cyclotron resonance case is new and was chosen it can magnify the effects of the particles on the gravitational wave. The cases are studied with regards to detectability of a medium induced dispersion. The influence on the gravitational wave propagation is, however, found to be too small for dispersive effects to be detected in the cases studied / Gravitationsvågor förutses i Einsteins allmänna relativitetsteori och har så här långt endast blivit indirekt detekterade. Den första direkta detektionen är dock bara en tidsfråga och observatorier runtom i världen arbetar hårt för att lyckas med den. Då gravitationsvågor väl är detekterade sägs de ha stor potential inom astronomi. För att man ska kunna tolka mätdata från gravitationsvågor behöver man veta hur vågen beter sig i propagationsmediet. Av den anledningen är syftet med detta examensarbete att undersöka hur gravitationsvågor beter sig i ett magnetiserat plasma. Med hjälp av en modell för kinetisk plasma, Einsteins fältekvationer och tetradformalism härleds en allmän lösning för en gravitationsvåg som propagerar i en magnetiserad plasma fram. Lösningen används därefter för att hitta dispersionsrelationen för gravitationsvågen givet två specialfall: fallet för Alfvénresonans och fallet för cyklotronresonens. Alfvénfallet är redan studerat i tidigare litteratur och resultatet man hittar visar sig stämma överens med det tidigare funna resultatet som säger att det inte har en märkbar påverkan på vågen. Cyklotronresonansfallet är nytt och valdes eftersom att det kan förstärka de effekter som partiklarna har på gravitationsvågen. De båda specialfallen studeras närmare med avseende på detektion av en dispersion inducerad av mediet. Påverkan på gravitationsvågens propagation sluts dock till att vara för liten för att den ska bli uppmätt i de undersökta fallen.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 110-116). Available also in a digital version from Dissertation Abstracts.

published_or_final_version / Physics / Master / Master of Philosophy

No description available.

The motivation of this thesis is to look for a signature of Lorentz violation, hopefully observable, in the gravitational waves emitted by cosmic strings. Aspects of cosmic strings are reviewed, in particular how focused bursts of gravitational radiation are emitted when a cusp forms on the string. The same phenomenon is then studied in an effective field theory with Lorentz violation called Einstein-aether theory. This is a simple theory with a dynamic preferred frame, but it retains rotational and diffeomorphism invariance. The linearized version of the theory produces five wave modes. We study the usual transverse traceless modes which now have a wave speed that can be lower or greater than the speed of light. This altered speed produces distinctive features in the waves. They depend on two free parameters: roughly the wave speed and the acceleration of the string cusp. The profile of the wave is analyzed in detail for different values of the parameters and explained by close comparison with the string motion.

The motivation of this thesis is to look for a signature of Lorentz violation, hopefully observable, in the gravitational waves emitted by cosmic strings. Aspects of cosmic strings are reviewed, in particular how focused bursts of gravitational radiation are emitted when a cusp forms on the string. The same phenomenon is then studied in an effective field theory with Lorentz violation called Einstein-aether theory. This is a simple theory with a dynamic preferred frame, but it retains rotational and diffeomorphism invariance. The linearized version of the theory produces five wave modes. We study the usual transverse traceless modes which now have a wave speed that can be lower or greater than the speed of light. This altered speed produces distinctive features in the waves. They depend on two free parameters: roughly the wave speed and the acceleration of the string cusp. The profile of the wave is analyzed in detail for different values of the parameters and explained by close comparison with the string motion.