110,625 research outputs found
The density of eigenvalues in thin circular conical shells
Resonant frequencies in thin circular conical shell
Entropy for Quark States
We discuss the quantum state structure using the standard model for three
colored quarks in the fundamental representations of making up the
singlet ground state of the hadrons. This allows us to calculate a finite von
Neumann entropy from the quantum reduced density matrix, which we explicitly
evaluate for the quarks in a model for the meson and baryon states. Finally we
look into the general effects and implications of entanglement in the
color space.Comment: 9 pages, 0 figure
Wind loads on flat plate photovoltaic array fields (nonsteady winds)
Techniques to predict the dynamic response and the structural dynamic loads of flat plate photovoltaic arrays due to wind turbulence were analyzed. Guidelines for use in predicting the turbulent portion of the wind loading on future similar arrays are presented. The dynamic response and the loads dynamic magnification factor of the two array configurations are similar. The magnification factors at a mid chord and outer chord location on the array illustrated and at four points on the chord are shown. The wind tunnel test experimental rms pressure coefficient on which magnification factors are based is shown. It is found that the largest response and dynamic magnification factor occur at a mid chord location on an array and near the trailing edge. A technique employing these magnification factors and the wind tunnel test rms fluctuating pressure coefficients to calculate design pressure loads due to wind turbulence is presented
Cross-calibration of Suzaku XIS and XMM-Newton EPIC using clusters of galaxies
We extend a previous cross-calibration study by the International
Astronomical Consortium for High Energy Calibration (IACHEC) on
XMM-Newton/EPIC, Chandra/ACIS and BeppoSAX/MECS X-ray instruments with clusters
of galaxies to Suzaku/XIS instruments. Our aim is to study the accuracy of the
energy-dependent effective area calibration of the XIS instruments by
comparison of spectroscopic temperatures, fluxes and fit residuals obtained
with Suzaku/XIS and XMM-Newton/EPIC-pn for the same cluster. The temperatures
measured in the hard 2.0-7.0 keV energy band with all instruments are
consistent within 5 %. However, temperatures obtained with the XIS instruments
in the soft 0.5-2.0 keV band disagree by 9-29 %. We investigated residuals in
the XIS soft band, which showed that if XIS0 effective area shape is accurately
calibrated, the effective areas of XIS1 and XIS3 are overestimated below 1.0
keV (or vice versa). Adjustments to the modelling of the column density of the
XIS contaminant in the 3-6 arcmin extraction region while forcing consistent
emission models in each instrument for a given cluster significantly improved
the fits. The oxygen column density in XIS1 and XIS3 contaminant must be
increased by 1-2E17 cm^-2 in comparison to the values implemented in the
current calibration, while the column density of the XIS0 contaminant given by
the analysis is consistent with the public calibration. XIS soft band
temperatures obtained with the modification to the column density of the
contaminant agree better with temperatures obtained with the EPIC-pn instrument
of XMM-Newton, than with those derived using the Chandra-ACIS instrument.
However, comparison of hard band fluxes obtained using Suzaku-XIS to fluxes
obtained using the Chandra-ACIS and EPIC-pn instruments proved inconclusive.Comment: 24 pages, 27 figures, accepted for publication in Astronomy &
Astrophysic
Conditions driving chemical freeze-out
We propose the entropy density as the thermodynamic condition driving best
the chemical freeze-out in heavy-ion collisions. Taking its value from lattice
calculations at zero chemical potential, we find that it is excellent in
reproducing the experimentally estimated freeze-out parameters. The two
characteristic endpoints in the freeze-out diagram are reproduced as well.Comment: 8 pages, 5 eps figure
Korean coastal water depth/sediment and land cover mapping (1:25,000) by computer analysis of LANDSAT imagery
Computer analysis was applied to single date LANDSAT MSS imagery of a sample coastal area near Seoul, Korea equivalent to a 1:50,000 topographic map. Supervised image processing yielded a test classification map from this sample image containing 12 classes: 5 water depth/sediment classes, 2 shoreline/tidal classes, and 5 coastal land cover classes at a scale of 1:25,000 and with a training set accuracy of 76%. Unsupervised image classification was applied to a subportion of the site analyzed and produced classification maps comparable in results in a spatial sense. The results of this test indicated that it is feasible to produce such quantitative maps for detailed study of dynamic coastal processes given a LANDSAT image data base at sufficiently frequent time intervals
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