28,538 research outputs found

    After heat distribution of a mobile nuclear power plant

    Get PDF
    A computer program was developed to analyze the transient afterheat temperature and pressure response of a mobile gas-cooled reactor power plant following impact. The program considers (in addition to the standard modes of heat transfer) fission product decay and transport, metal-water reactions, core and shield melting and displacement, and pressure and containment vessel stress response. Analyses were performed for eight cases (both deformed and undeformed models) to verify operability of the program options. The results indicated that for a 350 psi (241 n/sq cm) initial internal pressure, the containment vessel can survive over 100,000 seconds following impact before creep rupture occurs. Recommendations were developed as to directions for redesign to extend containment vessel life

    On the formation of current sheets in response to the compression or expansion of a potential magnetic field

    Full text link
    The compression or expansion of a magnetic field that is initially potential is considered. It was recently suggested by Janse & Low [2009, ApJ, 690, 1089] that, following the volumetric deformation, the relevant lowest energy state for the magnetic field is another potential magnetic field that in general contains tangential discontinuities (current sheets). Here we examine this scenario directly using a numerical relaxation method that exactly preserves the topology of the magnetic field. It is found that of the magnetic fields discussed by Janse & Low, only those containing magnetic null points develop current singularities during an ideal relaxation, while the magnetic fields without null points relax toward smooth force-free equilibria with finite non-zero current.Comment: Accepted for publication in Ap

    Gap Symmetry of Superconductivity in UPd2Al3

    Full text link
    The angle dependent thermal conductivity of the heavy-fermion superconductor UPd2_2Al3_3 in the vortex state was recently measured by Watanabe et al. Here we analyze this data from two perspectives: universal heat conduction and the angle-dependence. We conclude that the superconducting gap function Δ(k)\Delta({\bf k}) in UPd2_2Al3_3 has horizontal nodes and is given by Δ(k)=Δcos(2χ)\Delta({\bf k}) =\Delta\cos(2\chi), with χ=ckz\chi = ck_{z}.Comment: 8 pages, 4 figures, improved figures in replacemen

    Management of Chronic Non-malignant Pain in Nursing Homes Residents

    Get PDF
    Pain in nursing homes remains underassessed, underreported and undertreated, consequently, becoming a growing concern in the United States. The purpose of this inquiry is to review the current evidence guiding the management of chronic non-malignant pain among nursing home residents. Twelve articles relevant to this topic were obtained from a search of the electronic databases PubMed and Cumulative Index of Nursing and Allied Health (CINAHL). Findings underscore an urgent need to improve assessment, documentation, and management of pain in nursing home residents

    Quantum incompressibility of a falling Rydberg atom, and a gravitationally-induced charge separation effect in superconducting systems

    Get PDF
    Freely falling point-like objects converge towards the center of the Earth. Hence the gravitational field of the Earth is inhomogeneous, and possesses a tidal component. The free fall of an extended quantum object such as a hydrogen atom prepared in a high principal-quantum-number stretch state, i.e., a circular Rydberg atom, is predicted to fall more slowly that a classical point-like object, when both objects are dropped from the same height from above the Earth. This indicates that, apart from "quantum jumps," the atom exhibits a kind of "quantum incompressibility" during free fall in inhomogeneous, tidal gravitational fields like those of the Earth. A superconducting ring-like system with a persistent current circulating around it behaves like the circular Rydberg atom during free fall. Like the electronic wavefunction of the freely falling atom, the Cooper-pair wavefunction is "quantum incompressible." The ions of the ionic lattice of the superconductor, however, are not "quantum incompressible," since they do not possess a globally coherent quantum phase. The resulting difference during free fall in the response of the nonlocalizable Cooper pairs of electrons and the localizable ions to inhomogeneous gravitational fields is predicted to lead to a charge separation effect, which in turn leads to a large repulsive Coulomb force that opposes the convergence caused by the tidal, attractive gravitational force on the superconducting system. A "Cavendish-like" experiment is proposed for observing the charge separation effect induced by inhomogeneous gravitational fields in a superconducting circuit. This experiment would demonstrate the existence of a novel coupling between gravity and electricity via macroscopically coherent quantum matter.Comment: `2nd Vienna Symposium for the Foundations of Modern Physics' Festschrift MS for Foundations of Physic

    Inverse Scattering Transform for the Camassa-Holm equation

    Get PDF
    An Inverse Scattering Method is developed for the Camassa-Holm equation. As an illustration of our approach the solutions corresponding to the reflectionless potentials are explicitly constructed in terms of the scattering data. The main difference with respect to the standard Inverse Scattering Transform lies in the fact that we have a weighted spectral problem. We therefore have to develop different asymptotic expansions.Comment: 17 pages, LaTe
    corecore