539 research outputs found

    Errors in hybrid computers

    Get PDF
    Method is described for reduction of error components in numerical integration, sampling with zero hold order, and execution time delay

    Variable sweep wing configuration Patent

    Get PDF
    Variable sweep wing configuration for supersonic aircraf

    Subsonic and supersonic aerodynamic characteristics of an airplane configuration utilizing double-pivot variable-sweep wings

    Get PDF
    Subsonic and supersonic aerodynamic characteristics of aircraft configuration using double pivot variable sweep wing

    Give Me More Body: Pushing the Boundaries of Body and Soul

    Full text link
    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43553/1/11133_2005_Article_4214.pd

    Compact Stars - How Exotic Can They Be?

    Full text link
    Strong interaction physics under extreme conditions of high temperature and/or density is of central interest in modern nuclear physics for experimentalists and theorists alike. In order to investigate such systems, model approaches that include hadrons and quarks in a unified approach, will be discussed. Special attention will be given to high-density matter as it occurs in neutron stars. Given the current observational limits for neutron star masses, the properties of hyperonic and hybrid stars will be determined. In this context especially the question of the extent, to which exotic particles like hyperons and quarks affect star masses, will be discussed.Comment: Contributon to conference "Nuclear Physics: Present and Future", held in Boppard (Germany), May 201

    Codesigning health and other public services with vulnerable and disadvantaged populations: Insights from an international collaboration

    Get PDF
    Background Codesign has the potential to transform health and other public services. To avoid unintentionally reinforcing existing inequities, better understanding is needed of how to facilitate involvement of vulnerable populations in acceptable, ethical and effective codesign. Objective To explore citizens’ involvement in codesigning public services for vulnerable groups, identify challenges and suggest improvements. Design A modified case study approach. Pattern matching was used to compare reported challenges with a priori theoretical propositions. Setting and participants A two‐day international symposium involved 28 practitioners, academics and service users from seven countries to reflect on challenges and to codesign improved processes for involving vulnerable populations. Intervention studied Eight case studies working with vulnerable and disadvantaged populations in three countries. Results We identified five shared challenges to meaningful, sustained participation of vulnerable populations: engagement; power differentials; health concerns; funding; and other economic/social circumstances. In response, a focus on relationships and flexibility is essential. We encourage codesign projects to enact a set of principles or heuristics rather than following pre‐specified steps. We identify a set of principles and tactics, relating to challenges outlined in our case studies, which may help in codesigning public services with vulnerable populations. Discussion and conclusions Codesign facilitators must consider how meaningful engagement will be achieved and how power differentials will be managed when working with services for vulnerable populations. The need for flexibility and responsiveness to service user needs may challenge expectations about timelines and outcomes. User‐centred evaluations of codesigned public services are needed

    Diffusion controlled initial recombination

    Full text link
    This work addresses nucleation rates in systems with strong initial recombination. Initial (or `geminate') recombination is a process where a dissociated structure (anion, vortex, kink etc.) recombines with its twin brother (cation, anti-vortex, anti-kink) generated in the same nucleation event. Initial recombination is important if there is an asymptotically vanishing interaction force instead of a generic saddle-type activation barrier. At low temperatures, initial recombination strongly dominates homogeneous recombination. In a first part, we discuss the effect in one-, two-, and three-dimensional diffusion controlled systems with spherical symmetry. Since there is no well-defined saddle, we introduce a threshold which is to some extent arbitrary but which is restricted by physically reasonable conditions. We show that the dependence of the nucleation rate on the specific choice of this threshold is strongest for one-dimensional systems and decreases in higher dimensions. We discuss also the influence of a weak driving force and show that the transport current is directly determined by the imbalance of the activation rate in the direction of the field and the rate against this direction. In a second part, we apply the results to the overdamped sine-Gordon system at equilibrium. It turns out that diffusive initial recombination is the essential mechanism which governs the equilibrium kink nucleation rate. We emphasize analogies between the single particle problem with initial recombination and the multi-dimensional kink-antikink nucleation problem.Comment: LaTeX, 11 pages, 1 ps-figures Extended versio

    Quasiparticle Hall Transport of d-wave Superconductors in Vortex State

    Full text link
    We present a theory of quasiparticle Hall transport in strongly type-II superconductors within their vortex state. We establish the existence of integer quantum spin Hall effect in clean unconventional dx2y2d_{x^2-y^2} superconductors in the vortex state from a general analysis of the Bogoliubov-de Gennes equation. The spin Hall conductivity σxys\sigma^s_{xy} is shown to be quantized in units of 8π\frac{\hbar}{8\pi}. This result does not rest on linearization of the BdG equations around Dirac nodes and therefore includes inter-nodal physics in its entirety. In addition, this result holds for a generic inversion-symmetric lattice of vortices as long as the magnetic field BB satisfies Hc1BHc2H_{c1} \ll B \ll H_{c2}. We then derive the Wiedemann-Franz law for the spin and thermal Hall conductivity in the vortex state. In the limit of T0T \to 0, the thermal Hall conductivity satisfies κxy=4π23(kB)2Tσxys\kappa_{x y}=\frac{4\pi^2}{3}(\frac{k_B}{\hbar})^2 T \sigma^s_{xy}. The transitions between different quantized values of σxys\sigma^s_{xy} as well as relation to conventional superconductors are discussed.Comment: 18 pages REVTex, 3 figures, references adde
    corecore