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

Short-Wavelength Light-Blocking Eyeglasses Attenuate Symptoms of Eye Fatigue

Purpose: The purpose of this study was to determine whether subjects who wear short wavelength–blocking eyeglasses during computer tasks exhibit less visual fatigue and report fewer symptoms of visual discomfort than subjects wearing eyeglasses with clear lenses.Methods: A total of 36 healthy subjects (20 male; 16 female) was randomized to wearing no-block, low-blocking, or high-blocking eyeglasses while performing a 2-hour computer task. A masked grader measured critical flicker fusion frequency (CFF) as a metric of eye fatigue and evaluated symptoms of eye strain with a 15-item questionnaire before and after computer use.Results: We found that the change in CFF after the computer task was significantly more positive (i.e., less eye fatigue) in the high-block versus the no-block (P = 0.027) and low-block (P = 0.008) groups. Moreover, random assignment to the high-block group but not to the low-block group predicted a more positive change in CFF (i.e., less eye fatigue) following the computer task (adjusted β = 2.310; P = 0.002). Additionally, subjects wearing high-blocking eyeglasses reported significantly less feeling pain around/inside the eye (P = 0.0063), less feeling that the eyes were heavy (P = 0.0189), and less feeling that the eyes were itchy (P = 0.0043) following the computer task, when compared to subjects not wearing high-blocking lenses.Conclusions: Our results support the hypothesis that short-wavelength light-blocking eyeglasses may reduce eye strain associated with computer use based on a physiologic correlate of eye fatigue and on subjects\u27 reporting of symptoms typically associated with eye strain

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 1.3×10^5 to 6.5×10^3. 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 $Spitzer$ Infrared Array Camera (IRAC) Band 1 (3.6 $\mu$m) and Band 2 (4.5 $\mu$m), and 975 objects identified in Magellan 6.5m FourStar near-IR $J$ and $K_{\rm s}$ 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 $HST$ 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 $B-V$ versus $V-I$ 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 Blair’s political instinct typically is to associate himself only with the future. As such, his explicit appeal to ‘the past’ in his references to New Labour’s desire to establish a “new Bretton Woods” 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