Volume 78, Issue 1, January 2007
Index of content:
The National Aeronautics and Space Administration’s Spitzer Space Telescope (formerly the Space Infrared Telescope Facility) is the fourth and final facility in the Great Observatories Program, joining Hubble Space Telescope (1990), the Compton Gamma-Ray Observatory (1991–2000), and the Chandra X-Ray Observatory (1999). Spitzer, with a sensitivity that is almost three orders of magnitude greater than that of any previous ground-based and space-based infrared observatory, is expected to revolutionize our understanding of the creation of the universe, the formation and evolution of primitive galaxies, the origin of stars and planets, and the chemical evolution of the universe. This review presents a brief overview of the scientific objectives and history of infrared astronomy. We discuss Spitzer’s expected role in infrared astronomy for the new millennium. We describe pertinent details of the design, construction, launch, in-orbit checkout, and operations of the observatory and summarize some science highlights from the first two and a half years of Spitzer operations. More information about Spitzer can be found at http://spitzer.caltech.edu/.
- THERMOMETRY; THERMAL DIFFUSIVITY; ACOUSTIC; PHOTOTHERMAL AND PHOTOACOUSTIC
Three-axis acoustic device for levitation of droplets in an open gas stream and its application to examine sulfur dioxide absorption by water droplets78(2007); http://dx.doi.org/10.1063/1.2424454View Description Hide Description
Two acoustic devices to stabilize a droplet in an open gas stream (single-axis and three-axis levitators) have been designed and tested. The gas stream was provided by a jet apparatus with a exit diameter and a uniform velocity profile. The acoustic source used was a Langevin vibrator with a concave reflector. The single-axis levitator relied primarily on the radial force from the acoustic field and was shown to be limited because of significant droplet wandering. The three-axis levitator relied on a combination of the axial and radial forces. The three-axis levitator was applied to examine droplet deformation and circulation and to investigate the uptake of from the gas stream to the droplet.Droplets ranging in diameters from were levitated in gas streams with velocities up to . Droplet wandering was on the order of a half droplet diameter for a diameter droplet.Droplet circulation ranged from the predicted Hadamard-Rybczynski pattern to a rotating droplet pattern. Droplet over a central volume of the droplet was measured by planar laser induced fluorescence. The results for the decay of droplet versus time are in general agreement with published theory and experiments.