178 research outputs found
Mass segregation in the outer halo globular cluster Palomar 14
We present evidence for mass segregation in the outer-halo globular cluster
Palomar 14, which is intuitively unexpected since its present-day two-body
relaxation time significantly exceeds the Hubble time. Based on archival Hubble
Space Telescope imaging, we analyze the radial dependence of the stellar mass
function in the cluster's inner 39.2 pc in the mass range of 0.53-0.80 M_sun,
ranging from the main-sequence turn-off down to a V-band magnitude of 27.1 mag.
The mass function at different radii is well approximated by a power law and
rises from a shallow slope of 0.6+/-0.2 in the cluster's core to a slope of
1.6+/-0.3 beyond 18.6 pc. This is seemingly in conflict with the finding by
Beccari et al. (2011), who interpret the cluster's non-segregated population of
(more massive) blue straggler stars, compared to (less massive) red giants and
horizontal branch stars, as evidence that the cluster has not experienced
dynamical segregation yet. We discuss how both results can be reconciled. Our
findings indicate that the cluster was either primordially mass-segregated
and/or used to be significantly more compact in the past. For the latter case,
we propose tidal shocks as the mechanism driving the cluster's expansion, which
would imply that Palomar 14 is on a highly eccentric orbit. Conversely, if the
cluster formed already extended and with primordial mass segregation, this
could support an accretion origin of the cluster.Comment: 14 pages, 8 figures, accepted for publication in MNRA
Landslide Denied: Exit Polls vs. Vote Count 2006
There was an unprecedented level of concern approaching the 2006 Election ("E2006") about the vulnerability of the vote counting process to manipulation. With questions about the integrity of the 2000, 2002 and 2004 elections remaining unresolved, with e-voting having proliferated nationwide, and with incidents occurring with regularity through 2005 and 2006, the alarm spread from computer experts to the media and the public at large. It would be fair to say that America approached E2006 with held breath.For many observers, the results on Election Day permitted a great sigh of relief -- not because control of Congress shifted from Republicans to Democrats, but because it appeared that the public will had been translated more or less accurately into electoral results, not thwarted as some had feared. There was a relieved rush to conclude that the vote counting process had been fair and the concerns of election integrity proponents overblown.Unfortunately the evidence forces us to a very different and disturbing conclusion: there was gross vote count manipulation and it had a great impact on the results of E2006, significantly decreasing the magnitude of what would have been, accurately tabulated, a landslide of epic proportions. Because much of this manipulation appears to have been computer-based, and therefore invisible to the legions of at-the-poll observers, the public was informed of the usual "isolated incidents and glitches" but remains unaware of the far greater story: The electoral machinery and vote counting systems of the United States did not honestly and accurately translate the public will and certainly can not be counted on to do so in the future
Development of acceptance criteria for batches of silane primer for external tank thermal protection system bonding applications
Concluding tests for the thermogravimetric and FTIR analyses of DC 1200 silane primers are discussed as well as methods for HPLC and GC analyses and for determining titanium and silicon by atomic absorption spectroscopy. Tables summarizes results obtained for residue, ash, titanium, silicone, Si/Ti ratio, OH-absorption, the lap-shear test, and the GC headspace for alcohols
Solubility of Carbon Dioxide in Secondary Butyl Alcohol at High Pressures: Experimental and Modeling with CPA
Mixtures of carbon dioxide and secondary butyl alcohol at high pressures are interesting for a range of industrial applications. Therefore, it is important to have trustworthy experimental data on the high-pressure phase behavior of this mixture over a wide range of temperatures. In addition, an accurate thermodynamic model is necessary for the optimal design and operation of processes. In this study, bubble points of binary mixtures of CO2 + secondary butyl alcohol were measured using a synthetic method. Measurements covered a CO2 molar concentration range of (0.10–0.57) % and temperatures from (293 to 370) K, with pressures reaching up to 11 MPa. The experimental data were modelled by the cubic plus association (CPA) equation of state (EoS), as well as the more simple Soave–Redlich–Kwong (SRK) EoS. Predictive and correlative modes were considered for both models. In the predictive mode, the CPA performs better than the SRK because it also considers associations
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