152,066 research outputs found

    Constrained Molecular Dynamics Simulations of Atomic Ground-States

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    Constrained molecular dynamics(CoMD) model, previously introduced for nuclear dynamics, has been extended to the atomic structure and collision calculations. Quantum effects corresponding to the Pauli and Heisenberg principle are enforced by constraints, in a parameter-free way. Our calculations for small atomic system, H, He, Li, Be, F reproduce the ground-state binding energies within 3%, compared with the results of quantum mechanical Hartree-Fock calculations.Comment: 3 pages, 2 figure

    Persistent Problems in Medical Care

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    Analysis of F and G subdwarfs. 3 - An abundance analysis of the subdwarf mu Cassiopeia

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    Model atmospheric abundance analysis of subdwarf micron Cassiopeia constellatio

    Analytical fuel property effects, small combustors, phase 1

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    The effects of nonstandard aviation fuels on a typical small gas turbine combustor was analyzed. The T700/CT7 engine family was chosen as being representative of the class of aircraft power plants desired. Fuel properties, as specified by NASA, are characterized by low hydrogen content and high aromatics levels. Higher than normal smoke output and flame radiation intensity for the current T700 combustor which serves as a baseline were anticipated. It is, therefore, predicted that out of specification smoke visibility and higher than normal shell temperatures will exist when using NASA ERBS fuels with a consequence of severe reduction in cyclic life. Three new designs are proposed to compensate for the deficiencies expected with the existing design. They have emerged as the best of the eight originally proposed redesigns or combinations thereof. After the five choices that were originally made by NASA on the basis of competing performance factors, General Electric narrowed the field to the three proposed

    The Detailed Chemical Abundance Patterns of M31 Globular Clusters

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    We present detailed chemical abundances for >>20 elements in ∼\sim30 globular clusters in M31. These results have been obtained using high resolution (λ/Δλ∼\lambda/\Delta\lambda\sim24,000) spectra of their integrated light and analyzed using our original method. The globular clusters have galactocentric radii between 2.5 kpc and 117 kpc, and therefore provide abundance patterns for different phases of galaxy formation recorded in the inner and outer halo of M31. We find that the clusters in our survey have a range in metallicity of −2.2<-2.2<[Fe/H]<−0.11<-0.11. The inner halo clusters cover this full range, while the outer halo globular clusters at R>>20 kpc have a small range in abundance of [Fe/H]=−1.6±0.10=-1.6 \pm 0.10. We also measure abundances of alpha, r- and s-process elements. These results constitute the first abundance pattern constraints for old populations in M31 that are comparable to those known for the Milky Way halo.Comment: XII International Symposium on Nuclei in the Cosmos August 5-12, 2012 Cairns, Australia. To appear in Proceedings of Scienc
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