13,511 research outputs found
Phenolic cutter for machining foam insulation
Pre-pregged fiber glass is an efficient abrasive for machining polystyrene and polyurethane foams. It bonds easily to any cutter base made of aluminum, steel, or phenolic, is inexpensive, and is readily available
Observation of enhanced optical spring damping in a macroscopic mechanical resonator and application for parametric instability control in advanced gravitational-wave detectors
We show that optical spring damping in an optomechanical resonator can be enhanced by injecting a phase delay in the laser frequency-locking servo to rotate the real and imaginary components of the optical spring constant. This enhances damping at the expense of optical rigidity. We demonstrate enhanced parametric damping which reduces the Q factor of a 0.1-kg-scale resonator from 1.3Ă10^5 to 6.5Ă10^3. By using this technique adequate optical spring damping can be obtained to damp parametric instability predicted for advanced laser interferometer gravitational-wave detectors
The Infrared Massive Stellar Content of M83
We present an analysis of archival Spitzer images and new ground-based and
Hubble Space Telescope (HST) near-infrared (IR) and optical images of the field
of M83 with the goal of identifying rare, dusty, evolved massive stars. We
present point source catalogs consisting of 3778 objects from
Infrared Array Camera (IRAC) Band 1 (3.6 m) and Band 2 (4.5 m), and
975 objects identified in Magellan 6.5m FourStar near-IR and
images. A combined catalog of coordinate matched near- and mid-IR point sources
yields 221 objects in the field of M83. Using this photometry we identify 185
massive evolved stellar candidates based on their location in color-magnitude
and color-color diagrams. We estimate the background contamination to our
stellar candidate lists and further classify candidates based on their
appearance in Wide Field Camera 3 (WFC3) observations of M83. We find 49
strong candidates for massive stars which are very promising objects for
spectroscopic follow-up. Based on their location in a versus
diagram, we expect at least 24, or roughly 50%, to be confirmed as red
supergiants.Comment: 32 pages, 23 figures, accepted for publication in A&
Sand in the wheels, or oiling the wheels, of international finance? : New Labour's appeal to a 'new Bretton Woods'
Tony Blairâs political instinct typically is to associate himself only with the future. As such, his explicit appeal to âthe pastâ in his references to New Labourâs desire to establish a ânew Bretton Woodsâ is sufficient in itself to arouse some degree of analytical curiosity (see Blair 1998a). The fact that this appeal was made specifically in relation to Bretton Woods is even more interesting. The resonant image of the international economic context established by the original Bretton Woods agreements invokes a style and content of policy-making which Tony Blair typically dismisses as neither economically nor politically consistent with his preferred vision of the future (see Blair 2000c, 2001b)
Dynamical instabilities of Bose-Einstein condensates at the band-edge in one-dimensional optical lattices
We report on experiments that demonstrate dynamical instability in a
Bose-Einstein condensate at the band-edge of a one-dimensional optical lattice.
The instability manifests as rapid depletion of the condensate and conversion
to a thermal cloud. We consider the collisional processes that can occur in
such a system, and perform numerical modeling of the experiments using both a
mean-field and beyond mean-field approach. We compare our numerical results to
the experimental data, and find that the Gross-Pitaevskii equation is not able
to describe this experiment. Our beyond mean-field approach, known as the
truncated Wigner method, allows us to make quantitative predictions for the
processes of parametric growth and thermalization that are observed in the
laboratory, and we find good agreement with the experimental results.Comment: v2: Added several reference
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