43,773 research outputs found

    Scaling Laws for Non-Intercommuting Cosmic String Networks

    Full text link
    We study the evolution of non-interacting and entangled cosmic string networks in the context of the velocity-dependent one-scale model. Such networks may be formed in several contexts, including brane inflation. We show that the frozen network solution LaL\propto a, although generic, is only a transient one, and that the asymptotic solution is still LtL\propto t as in the case of ordinary (intercommuting) strings, although in the present context the universe will usually be string-dominated. Thus the behaviour of two strings when they cross does not seem to affect their scaling laws, but only their densities relative to the background.Comment: Phys. Rev. D (in press); v2: final published version (references added, typos corrected

    Search for Lorentz Violation in a Short-Range Gravity Experiment

    Full text link
    An experimental test of the Newtonian inverse square law at short range has been used to set limits on Lorentz violation in the pure gravity sector of the Standard-Model Extension. On account of the planar test mass geometry, nominally null with respect to inverse square forces, the limits derived for the SME coefficients of Lorentz violation are on the order s ~ 10000.Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28-July 2, 201

    The influence of large-scale motion on turbulent transport for confined coaxial jets

    Get PDF
    The existence of large-scale coherent structures in turbulent shear flows has been well documented in the literature. The importance of these structures in flow entrainment, momentum transport and mass transport in the shear layer has been suggested by several researchers. Comparisons between existing models and experimental data for shear flow in confined coaxial jets reinforce the necessity of further investigation of the large scale structures. These comparisons show the greatest discrepancy between prediction and actual results in the developing flow region where the large scales exist. It was also observed that the momentum transport rate comparisons were very bad. Finally, Schetz has reviewed mixing flows and concluded that large-scale structures were essential aspects of future modeling efforts

    The United Kingdom Ministry of Defence – the Case for Followership as a key Element of Leadership Development

    Get PDF
    Published in Strategic Management Quarterly (2015) Vol 3 Issue 4Using the Kelley (1992) Followership Style instrument this study explores the role and perceptions of Followership within the UK Ministry of Defence. In particular, within the Armed Services and the Civil Service it was apparent from the literature that only the RAF formally recognised the role of Followership within their Leadership staff development programmes, hence the research aimed to see whether this was reflected in self-perceptions of Followership Style and the extent to which it is applied within the organisation. The analysis concluded that the analysed sample (298 responses) produced an atypical profile compared to other studies that have used the instrument. The RAF showed statistically significant higher scores than the other Armed Services or the Civil Servants and scores increased with Rank/Grade. The analysis also highlighted that the individuals seemed not to be recognised as good Followers by their leaders, they appeared not to recognise their reports as good Followers and in all cases the organisation seemed not to recognise their value. These aspects provide scope for further research to better understand the organisational culture, processes and practices that appear to act as a barrier to the extraction of the benefits of having good Followers even in an area where Star Followers dominate

    Symbiotic approaches to work and technology

    Get PDF
    Production Planning;production

    Compression Bases in Unital Groups

    Full text link
    We study unital groups with a distinguished family of compressions called a compression base. A motivating example is the partially ordered additive group of a von Neumann algebra with all Naimark compressions as the compression base.Comment: 8 page

    Influence of large-scale motion on turbulent transport for confined coaxial jets. Volume 1: Analytical analysis of the experimental data using conditional sampling

    Get PDF
    The existence of large scale coherent structures in turbulent shear flows has been well documented. Discrepancies between experimental and computational data suggest a necessity to understand the roles they play in mass and momentum transport. Using conditional sampling and averaging on coincident two component velocity and concentration velocity experimental data for swirling and nonswirling coaxial jets, triggers for identifying the structures were examined. Concentration fluctuation was found to be an adequate trigger or indicator for the concentration-velocity data, but no suitable detector was located for the two component velocity data. The large scale structures are found in the region where the largest discrepancies exist between model and experiment. The traditional gradient transport model does not fit in this region as a result of these structures. The large scale motion was found to be responsible for a large percentage downstream at approximately the mean velocity of the overall flow in the axial direction. The radial mean velocity of the structures was found to be substantially greater than that of the overall flow

    A comparative analysis of the decoupling effects in a magnetic forming beryllium coil assembly

    Get PDF
    Digital computer for determining currents and forces in magnetic forming beryllium coil assembl
    corecore