Showing items related by title, author, creator and subject.

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  Vibrations in MagAO: frequency-based analysis of on-sky data, resonance sources identification, and future challenges in vibrations mitigation

  Zúñiga, Sebastián; Garcés, Javier; Close, Laird M.; Males, Jared R.; Morzinski, Katie M.; Escárate, Pedro; Castro, Mario; Marchioni, José; Zagals, Diego; Univ Arizona, Dept Astron, CAAO; et al. (SPIE-INT SOC OPTICAL ENGINEERING, 2016-07-27)

  Frequency-based analysis and comparisons of tip-tilt on-sky data registered with 6.5 Magellan Telescope Adaptive Optics (MagAO) system on April and Oct 2014 was performed. Twelve tests are conducted under different operation conditions in order to observe the influence of system instrumentation (such as fans, pumps and louvers). Vibration peaks can be detected, power spectral densities (PSDs) are presented to reveal their presence. Instrumentation-induced resonances, close-loop gain and future challenges in vibrations mitigation techniques are discussed.
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  The effects of postural drainage, manual percussion and vibration versus postural drainage and mechanical vibration on maximal expiratory flows

  Hartsell, Marilyn Burke (The University of Arizona., 1978)
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  THE VIBRATIONAL AND ELECTRONIC ABSORPTION SPECTRA OF SILVER-LITHIUM, SILVER-SODIUM, COPPER-LITHIUM, AND COPPER-SODIUM FROM SINGLE MOLECULES TO SMALL PARTICLES.

  PFLIBSEN, KENT PAUL. (The University of Arizona., 1984)

  Vibrational and electronic absorption spectra of metal alloy molecules and small particles have been measured. The matrix isolation technique was used to produce the samples. Dissimilar metals were combined to provide far infrared vibrational activity. Through the study of the electronic and vibrational excitation spectra, metallic interatomic binding potential characteristics could be investigated. The absorption spectra of the molecular systems were modelled using the extended Hueckel method, for the electronic excitations, and a dynamical matrix-normal mode technique for the vibrational excitations. Surface plasmon absorption, from the metal alloy particles, could not be measured but surface phonon absorption was measured. Electronic and vibrational absorption lines in alloyed metal molecules were measured and compared to the calculations. A surface diffusion model was developed to explain the dependences of molecule and particle size on the experimentally controlled system parameters.