Development flight tests of JetStar LFC leading-edge flight test experiment

The overall objective of the flight tests on the JetStar aircraft was to demonstrate the effectiveness and reliability of laminar flow control under representative flight conditions. One specific objective was to obtain laminar flow on the JetStar leading-edge test articles for the design and off-design conditions. Another specific objective was to obtain operational experience on a Laminar Flow Control (LFC) leading-edge system in a simulated airline service. This included operational experience with cleaning requirements, the effect of clogging, possible foreign object damage, erosion, and the effects of ice particle and cloud encounters. Results are summarized

Towards a Unified Quark-Hadron Matter Equation of State for Applications in Astrophysics and Heavy-Ion Collisions

We outline an approach to a unified equation of state for quark-hadron matter on the basis of a $\Phi-$derivable approach to the generalized Beth-Uhlenbeck equation of state for a cluster decomposition of thermodynamic quantities like the density. To this end we summarize the cluster virial expansion for nuclear matter and demonstrate the equivalence of the Green's function approach and the $\Phi-$derivable formulation. For an example, the formation and dissociation of deuterons in nuclear matter is discussed. We formulate the cluster $\Phi-$derivable approach to quark-hadron matter which allows to take into account the specifics of chiral symmetry restoration and deconfinement in triggering the Mott-dissociation of hadrons. This approach unifies the description of a strongly coupled quark-gluon plasma with that of a medium-modified hadron resonance gas description which are contained as limiting cases. The developed formalism shall replace the common two-phase approach to the description of the deconfinement and chiral phase transition that requires a phase transition construction between separately developed equations of state for hadronic and quark matter phases. Applications to the phenomenology of heavy-ion collisions and astrophysics are outlined.Comment: 35 pages, 3 figures, Special Issue "Compact Stars in the QCD Phase Diagram

Strange matter prospects within the string-flip model

In this contribution we extend the recently developed two-flavor quark-matter string-flip model by including strange quarks. We discuss implications for compact stars.Comment: 4 pages, 4 figures, proceedings to SQM201

Spectroscopic Abundances in Cool Pleiades Dwarfs and NGC 2264 Stars

We derive parameters and abundances of several elements in two cool Pleiades dwarfs, four cool NGC 2264 pre-main-sequence stars, and a probable NGC 2264 nonmember from high-resolution, moderate signal-to-noise ratio, Keck/HIRES spectra. Our Pleiades Fe abundance agrees with previous spectroscopic and photometric values of hotter stars and does not resolve the 0.3 mag distance modulus discrepancy between main-sequence fitting and Hipparcos parallaxes. Abundances of Cr-Ca-Ti-Al are subsolar, mimicking the pattern of interstellar medium abundances. While modest temperature errors may contribute, the results (particularly for Al) could suggest an association with ionization potential; such effects might be related to the Pleiades Li scatter. The cluster Fe scatter and its relation to Li scatter is discussed. Three NGC 2264 members suggest [Fe/H] = -0.15 and near-solar ratios of other elements. Mildly supersolar abundances for another object support its probable nonmembership. A fourth member exhibits an Mg-Si-Fe-Ni and Cr-Ti-Ca-Al dichotomy opposite to that of the Pleiades stars; a relation to ionization potential is again suggested. A 0.15-0.20 dex scatter or steep decline, neither well accommodated by stellar models, in the NGC 2264 Li abundances with Teff is indicated. We note the surprising presence of the λ7774 O I triplet in our Pleiades stars, one of the cool NGC 2264 stars, and the K6 field dwarf GL 241. The inferred LTE O abundances are enhanced by 0.23-0.85 dex over solar, suggesting that even non-LTE calculations of the O I triplet are incomplete and perhaps implicating the influence of an overlying chromosphere. Our results demonstrate the utility of cluster abundances besides Fe and Li in addressing fundamental issues concerning stellar evolution and systematic errors in the analysis of cool young stars

Simulated airline service experience with laminar-flow control leading-edge systems

The first JetStar leading edge flight test was made November 30, 1983. The JetStar was flown for more than 3 years. The titanium leading edge test articles today remain in virtually the same condition as they were in on that first flight. No degradation of laminar flow performance has occurred as a result of service. The JetStar simulated airline service flights have demonstrated that effective, practical leading edge systems are available for future commercial transports. Specific conclusions based on the results of the simulated airline service test program are summarized

VIPR: A probabilistic algorithm for analysis of microbial detection microarrays

<p>Abstract</p> <p>Background</p> <p>All infectious disease oriented clinical diagnostic assays in use today focus on detecting the presence of a single, well defined target agent or a set of agents. In recent years, microarray-based diagnostics have been developed that greatly facilitate the highly parallel detection of multiple microbes that may be present in a given clinical specimen. While several algorithms have been described for interpretation of diagnostic microarrays, none of the existing approaches is capable of incorporating training data generated from positive control samples to improve performance.</p> <p>Results</p> <p>To specifically address this issue we have developed a novel interpretive algorithm, VIPR (<b>V</b>iral <b>I</b>dentification using a <b>PR</b>obabilistic algorithm), which uses Bayesian inference to capitalize on empirical training data to optimize detection sensitivity. To illustrate this approach, we have focused on the detection of viruses that cause hemorrhagic fever (HF) using a custom HF-virus microarray. VIPR was used to analyze 110 empirical microarray hybridizations generated from 33 distinct virus species. An accuracy of 94% was achieved as measured by leave-one-out cross validation. <it>Conclusions</it></p> <p>VIPR outperformed previously described algorithms for this dataset. The VIPR algorithm has potential to be broadly applicable to clinical diagnostic settings, wherein positive controls are typically readily available for generation of training data.</p

Spectroscopic Abundances of Solar-Type Dwarfs in the Open Cluster M34 (NGC 1039)

Parameters and relative abundances of Fe, Ni, Ti, Cr, Ca, Si, Al, and Mg have been derived for nine M34 G and K dwarfs from high-resolution, modest signal-to-noise ratio Keck HIRES spectra. Effective temperatures have been derived spectroscopically and fall in the range 4750 K Teff 6130 K. Despite modest scatter in Fe, Ti, Cr, Ca, Al, and Mg (none of which is found to be correlated with Li scatter in M34), our two coolest stars are slightly though consistently underabundant in these elements relative to the warmer stars. The two cool stars are slightly overabundant in Si, whose abundances are derived from higher excitation lines. This and our finding that Fe ii–based abundances are significantly higher than Fe i–based values in the cool stars seem to point toward the action of non-LTE effects (overionization, overexcitation, or both), though additional analysis is required to exclude inadequacies in the model atmospheres. Final mean cluster abundances are based on five warm stars, which indicate [Fe/H] = +0.07 Æ0.04, and are void of any statistically significant scatter. The other elements scale well with Fe except for Ni, which appears to be slightly underabundant with respect to Fe. Potassium abundances are derived and show a surprising marked trend with temperature, which further supports our suspicion of the presence of non-LTE effects. Moreover, similar trends with temperature suggest that the Li and K underabundances in cool M34 dwarfs are partially related; thus, some portion of the well-known Li-Teff trend in cool M34 dwarfs may be illusory

Infrared Space Observatory Polarimetric Imaging of the Egg Nebula (RAFGL 2688)

We present polarimetric imaging of the protoplanetary nebula RAFGL 2688 obtained at 4.5 microns with the Infrared Space Observatory (ISO). We have deconvolved the images to remove the signature of the point spread function of the ISO telescope, to the extent possible. The deconvolved 4.5 micron image and polarimetric map reveal a bright point source with faint, surrounding reflection nebulosity. The reflection nebula is brightest to the north-northeast, in agreement with previous ground- and space-based infrared imaging. Comparison with previous near-infrared polarimetric imaging suggests that the polarization of starlight induced by the dust grains in RAFGL 2688 is more or less independent of wavelength between 2 microns and 4.5 microns. This, in turn, indicates that scattering dominates over thermal emission at wavelengths as long as ~5 microns, and that the dust grains have characteristic radii < 1 micron.Comment: 27 pages, 9 figures; to appear in the Astronomical Journal, May 2002 issu