306 research outputs found

    Bethe Ansatz solution of a decagonal rectangle triangle random tiling

    Full text link
    A random tiling of rectangles and triangles displaying a decagonal phase is solved by Bethe Ansatz. Analogously to the solutions of the dodecagonal square triangle and the octagonal rectangle triangle tiling an exact expression for the maximum of the entropy is found.Comment: 17 pages, 4 figures, some remarks added and typos correcte

    Static Envelope Patterns in Composite Resonances Generated by Level Crossing in Optical Toroidal Microcavities

    Get PDF
    We study level crossing in the optical whispering-gallery (WG) modes by using toroidal microcavities. Experimentally, we image the stationary envelope patterns of the composite optical modes that arise when WG modes of different wavelengths coincide in frequency. Numerically, we calculate crossings of levels that correspond with the observed degenerate modes, where our method takes into account the not perfectly transverse nature of their field polarizations. In addition, we analyze anticrossing with a large avoidance gap between modes of the same azimuthal number

    The effect of consumer attitudes on design for product longevity: the case of the fashion industry

    Get PDF
    Product longevity is a key aspect of sustainability and encouraging consumers to prolong the lifetime of products therefore has a part to play in minimising environmental sustainability impacts. The production, distribution and disposal phases of the clothing life cycle all create environmental impacts, but extending garments’ active life via design, maintenance and re-use of clothing is the most effective method of reducing the negative effects of the clothing industry on the environment. The study took an exploratory approach using mixed qualitative research methods to investigate consumer perspectives on clothing longevity and explore everyday processes and practices of clothing use, e.g. purchase, wear, care, maintenance, repair, re-use and disposal. The research findings showed that numerous factors affect consumers’ perspectives of clothing longevity during the purchase, usage and disposal stages of the clothing lifecycle. The conclusion addresses how these factors can influence product design practice in the fashion industry

    Tight focusing of plane waves from micro-fabricated spherical mirrors

    Full text link
    We derive a formula for the light field of a monochromatic plane wave that is truncated and reflected by a spherical mirror. Our formula is valid even for deep mirrors, where the aperture radius approaches the radius of curvature. We apply this result to micro-fabricated mirrors whose size scales are in the range of tens to hundreds of wavelengths, and show that sub-wavelength spot sizes can be achieved. This opens up the possibility of scalable arrays of tightly focused optical dipole traps without the need for high-performance optical systems.Comment: 8 pages, 5 color figures, 1 .sty file; changes made in response to referee comments; published in Optics Expres

    Exact Solution of an Octagonal Random Tiling Model

    Get PDF
    We consider the two-dimensional random tiling model introduced by Cockayne, i.e. the ensemble of all possible coverings of the plane without gaps or overlaps with squares and various hexagons. At the appropriate relative densities the correlations have eight-fold rotational symmetry. We reformulate the model in terms of a random tiling ensemble with identical rectangles and isosceles triangles. The partition function of this model can be calculated by diagonalizing a transfer matrix using the Bethe Ansatz (BA). The BA equations can be solved providing {\em exact} values of the entropy and elastic constants.Comment: 4 pages,3 Postscript figures, uses revte

    Managing sustainability in the fashion business: challenges in product development for clothing longevity in the UK

    Get PDF
    The production, distribution and disposal phases of the clothing life cycle all create environmental impacts, but life cycle assessment has found that extending garments' active life via design, maintenance and re-use of clothing is an effective method of reducing the environmental sustainability impacts of the clothing industry. The research in this article adopts a qualitative methodology focused on interviews with stakeholders from companies in the clothing sector. With regard to actions to support sustainability through clothing longevity, a range of responses were analysed thematically, alongside other key issues in clothing longevity, one of the most consistent themes being improvement in knowledge and skills. This study found that challenges to enhancing clothing longevity could be addressed via improved knowledge, skills, process and infrastructure, if managerial decisions were taken to reduce barriers to longevity and to enhance the agency of NPD teams in this respect

    Maser Oscillation in a Whispering-Gallery-Mode Microwave Resonator

    Full text link
    We report the first observation of above-threshold maser oscillation in a whispering-gallery(WG)-mode resonator, whose quasi-transverse-magnetic, 17th azimuthal-order WG mode, at a frequency of approx. 12.038 GHz, with a loaded Q of several hundred million, is supported on a cylinder of mono-crystalline sapphire. An electron spin resonance (ESR) associated with Fe3+ ions, that are substitutively included within the sapphire at a concentration of a few parts per billion, coincides in frequency with that of the (considerably narrower) WG mode. By applying a c.w. `pump' to the resonator at a frequency of approx. 31.34 GHz, with no applied d.c. magnetic field, the WG (`signal') mode is energized through a three-level maser scheme. Preliminary measurements demonstrate a frequency stability (Allan deviation) of a few times 1e-14 for sampling intervals up to 100 s.Comment: REVTeX v.4, 3 pages, with a separate .bbl file and 3 .eps figure
    • …
    corecore