Interferometric Gravitational Wave Detectors

The existence of gravitational waves is an important proof of Einstein’s theory of general relativity and took 100 years to be achieved using optical interferometry. This work describes how such a detector works and how it can change the way of seeing the Universe. Kilometers size laser interferometers are being built around the world in the way to make gravitational astronomy; detectors already built in the United States, Italy, and Japan will join efforts with detectors built in Japan and India and provide humanity with the means to see gravitational interactions of black holes and neutron star. Interactions, without these detectors, will be forever out of our sight

Can lightning be a noise source for a spherical gravitational wave antenna?

The detection of gravitational waves is a very active research field at the moment. In Brazil the gravitational wave detector is called Mario SCHENBERG. Due to its high sensitivity it is necessary to model mathematically all known noise sources so that digital filters can be developed that maximize the signal-to-noise ratio. One of the noise sources that must be considered are the disturbances caused by electromagnetic pulses due to lightning close to the experiment. Such disturbances may influence the vibrations of the antenna's normal modes and mask possible gravitational wave signals. In this work we model the interaction between lightning and SCHENBERG antenna and calculate the intensity of the noise due to a close lightning stroke in the detected signal. We find that the noise generated does not disturb the experiment significantly.Comment: 5 pages, 6 figure

Correlação entre variáveis térmicas de solidificação, microestrutura e resistência mecânica da liga Al-10%Si-2%Cu

As condições operacionais impostas nos processos de fundição geram, como consequência direta, uma diversidadede estruturas de solidificação. Em geral, as propriedades mecânicas mostram-se fortemente dependentesda morfologia estrutural e da composição química. Um aço de baixo carbono foi utilizado para promoverfluxo de calor unidirecional durante a solidificação e obter o arranjo da microestrutura. O objetivo deste trabalhoé pesquisar a influência das variáveis térmicas de solidificação na microestrutura da liga Al-10%Si-2%Cu e na sua resistência mecânica. Resultados experimentais incluem os espaçamentos dendríticos primários(EDP), velocidade de deslocamento da isoterma liquidus (VL), taxa de resfriamento (TR) e limites deresistência à tração (LRT) e de escoamento (LE). Estruturas dendríticas mais grosseiras tendem a diminuir aresistência à tração e ao escoamento na liga em estudo

Optimization of two-mechanical-mode transducers for gravitational wave detectors

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

Optimization of two-mechanical-mode transducers for gravitational wave detectors

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

Sector accounting policies Guidance and explanatory notes

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A geometric method for location of gravitational wave sources

We show that the interaction of a gravitational wave with a spherical resonant-mass antenna changes the antenna\u27s shape to that of an ellipsoid. These changes in shape always determine the direction of the incoming wave and may provide information on the wave\u27s polarization. We present a new approach for determining the position of astrophysical sources of gravitational waves which involves fewer calculations than in earlier methods. We also show how the measured quantities relate to the energy density of the wave. © 1997. The American Astronomical Society. All rights reserved

Determination of astrophysical parameters from the spherical gravitational wave detector data

The response of a spherical resonant-mass gravitational wave antenna can be written in terms of symmetric trace-free tensors. We apply this formalism to determine the direction of an incoming monochromatic wave, the orientation of its polarization ellipse and the wave\u27s two independent amplitudes, using the response amplitudes at five different points on the sphere surface. This formalism also allows us to determine the directions of burst sources