1,511 research outputs found

    Potential utilization of scallop viscera for solid waste management and as feedstuff for swine

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    Waste management has been identified as a major problem which will threaten the economic security of Florida's seafood industry within the next ten years (1). One of the primary concerns is treatment and disposal of solid wastes resulting from seafood processing. Utilization of scallop viscera as silage, much like that developed for waste fish and fish offal (3,4), could represent a practical solid waste treatment option which offers the additional benefit of a protein feed supplement for production of swine. (27pp.

    Two-photon E1M1 decay of 2 3P0 states in heavy heliumlike ions

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    Two-photon E1M1 transition rates are evaluated for heliumlike ions with nuclear charges in the range Z = 50-94. The two-photon rates modify previously published lifetimes/transition rates of 2 3P0 states. For isotopes with nuclear spin I not equal 0, where hyperfine quenching dominates the 2 3P0 decay, two-photon contributions are significant; for example, in heliumlike 187 Os the two-photon correction is 3% of the total rate. For isotopes with I= 0, where the 2 3P0 decay is unquenched, the E1M1 corrections are even more important reaching 60% for Z=94. Therefore, to aid in the interpretation of experiments on hyperfine quenching in heliumlike ions and to provide a more complete database for unquenched transitions, a knowledge of E1M1 rates is important.Comment: 6 pages, 3 figures, 3 table

    Disa cochlearis, a new orchid species from the Karoo region of South Africa

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    Disa cochlearis Johnson and Liltved, a new orchid species from the Elandsberg mountains in the semi-arid Karoo region is described. The plants occur in a dry habitat which supports few orchid species. The new taxon is not closely allied to any other known species of Disa, but is tentatively placed within Disa Section Amphigena on the grounds of its having similar vegetative morphology

    Third-order relativistic many-body calculations of energies and lifetimes of levels along the silver isoelectronic sequence

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    Energies of 5l_j (l= s, p, d, f, g) and 4f_j states in neutral Ag and Ag-like ions with nuclear charges Z = 48 - 100 are calculated using relativistic many-body perturbation theory. Reduced matrix elements, oscillator strengths, transition rates and lifetimes are calculated for the 17 possible 5l_j-5l'_{j'} and 4f_j-5l_{j'} electric-dipole transitions. Third-order corrections to energies and dipole matrix elements are included for neutral Ag and for ions with Z60. Comparisons are made with available experimental data for transition energies and lifetimes. Correlation energies and transition rates are shown graphically as functions of nuclear charge Z for selected cases. These calculations provide a theoretical benchmark for comparison with experiment and theory.Comment: 8 page

    Relativistic many-body calculations of electric-dipole matrix elements, lifetimes and polarizabilities in rubidium

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    Electric-dipole matrix elements for ns-n'p, nd-n'p, and 6d-4f transitions in Rb are calculated using a relativistic all-order method. A third-order calculation is also carried out for these matrix elements to evaluate the importance of the high-order many-body perturbation theory contributions. The all-order matrix elements are used to evaluate lifetimes of ns and np levels with n=6, 7, 8 and nd levels with n=4, 5, 6 for comparison with experiment and to provide benchmark values for these lifetimes. The dynamic polarizabilities are calculated for ns states of rubidium. The resulting lifetime and polarizability values are compared with available theory and experiment.Comment: 8 pages, 2 figure

    Combined effect of coherent Z exchange and the hyperfine interaction in atomic PNC

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    The nuclear spin-dependent parity nonconserving (PNC) interaction arising from a combination of the hyperfine interaction and the coherent, spin-independent, PNC interaction from Z exchange is evaluated using many-body perturbation theory. For the 6s-7s transition in 133Cs, we obtain a result that is about 40% smaller than that found previously by Bouchiat and Piketty [Phys. Lett. B 269, 195 (1991)]. Applying this result to 133Cs, leads to an increase in the experimental value of nuclear anapole moment and exacerbates differences between constraints on PNC meson coupling constants obtained from the Cs anapole moment and those obtained from other nuclear parity violating experiments. Nuclear spin-dependent PNC dipole matrix elements, including contributions from the combined weak-hyperfine interaction, are also given for the 7s-8s transition in 211Fr and for transitions between ground-state hyperfine levels in K, Rb, Cs, Ba+, Au, Tl, Fr, and Ra+.Comment: Revtex4 preprint 19 pages 4 table

    Multipole (E1, M1, E2, M2) transition wavelengths and rates between states with n<= 6 in heliumlike carbon, nitrogen, oxygen, neon, silicon, and argon

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    Transition wavelengths and rates are given for E1, E2, M1, and M2 transitions between singlet and triplet S, P, D, and F states in heliumlike ions of astrophysical interest: carbon, nitrogen, oxygen, neon, silicon, and argon. All possible transitions between states with n <= 6 are considered. Wave functions and energies are calculated using the relativistic configuration-interaction (CI) method including both Coulomb and Breit interactions. For transitions to the ground state, the present theoretical wavelengths agree to five digits with precise measurements.Comment: 8 pages of text 97 pages of tables submitted to Atomic & Data Nuclear Datable

    Metallurgical bonding development of V–4Cr–4Ti alloy for the DIII-D radiative divertor program

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    General Atomics (GA), in conjunction with the Department of Energy`s (DOE) DIII-D Program, is carrying out a plan to utilize a vanadium alloy in the DIII-D tokamak as part of the DIII-D Radiative Divertor (RD) upgrade. The V-4Cr-4Ti alloy has been selected in the U.S. as the leading candidate vanadium alloy for fusion applications. This alloy will be used for the divertor fabrication. Manufacturing development with the V-4Cr-4Ti alloy is a focus of the DIII-D RD Program. The RD structure, part of which will be fabricated from V-4Cr-4Ti alloy, will require many product forms and types of metal/metal bonded joints. Metallurgical bonding methods development on this vanadium alloy is therefore a key area of study by GA. Several solid state (non-fusion weld) and fusion weld joining methods are being investigated. To date, GA has been successful in producing ductile, high strength, vacuum leak tight joints by all of the methods under investigation. The solid state joining was accomplished in air, i.e., without the need for a vacuum or inert gas environment to prevent interstitial impurity contamination of the V-4Cr-4Ti alloy
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