Water wave propagation and scattering over topographical bottoms

Here I present a general formulation of water wave propagation and scattering over topographical bottoms. A simple equation is found and is compared with existing theories. As an application, the theory is extended to the case of water waves in a column with many cylindrical steps

Milagro limits and HAWC sensitivity for the rate-density of evaporating Primordial Black Holes

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Effect of density on growth and survival of ornate rock lobster, Panulirus ornatus (Fabricius, 1798), in a flow-through raceway system

Juvenile ornate rock lobsters (Panulirus ornatus) (3.240.09 g; 13.80.13 mm CL) captured from the wild were stocked at three densities (14, 29, and 43 m–2) within each of four 4000-L fibreglass raceway tanks with flow-through seawater supply. Lobsters were provided with shelters consisting of opaque polyethylene platforms, 600 mm × 600 mm, supported on six 100-mm legs and were fed continually through the night with a commercial penaeid prawn (P. japonicus) pellet supplemented with prawn flesh once per day. Growth and survival were monitored by means of a monthly sample of 20 lobsters from each experimental unit. After 272 days, density treatments did not differ significantly in survival, which averaged 52.5% (2.8). Lobster size was also unaffected by density, and mean size for all lobsters was 225.34.68 g (61.84.7 mm CL) at harvest. Mortality was consistent through time and was almost entirely attributable to cannibalism of postmoult individuals. The cannibalism may have been due to inappropriate shelter and feeding strategy. Despite higher mortality than anticipated, growth was rapid, representing a specific growth rate of 1.56% day–1, sufficient to permit growth from 3 g to 1 kg within 18 months. The experiment confirmed the excellent potential of P. ornatus for commercial aquaculture

Periodic Structures in Waveguides

Weconsider strder of per d 2 spanning a two-dimensional waveguide of width 2N . Scatter1 pratter wher Neumann conditionsar imposed on the boundar of thestr1 andeither Neumannor Dira hlet conditionsar applied on the guide wallsar decomposed into N +1 independent prTThe existence of at least Ntr ed modes is pr vedfor the Neumann guide case andfor the Dir hlet case wepr ve that at least N -1 such modes exist, this number incrTto N if acer geometr1 condition is satisfied. 1 Int1 duct03 In an investigation into the scattering of surface gravity waves by a long but finite array of bottomCzjB ted vertical circular cylinders, Maniar andNewm# (1997) discovered that in certaincircumO+#B=w and at particular frequencies the hydrodynamz loads on the cylinders could becom abnormCz+ large. They identified thisphenomHOw with the existence of resonant trapped m des when cylinders are placed in channels on the walls of which either Neumrw or Dirichlet boundary conditions are applied. For a single ci..

Electromagnetic guided waves on linear arrays of spheres

NOTICE: this is the author’s version of a work that was accepted for publication in Wave Motion. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in: Wave Motion, 2013, 50(1); http://dx.doi.org/10.1016/j.wavemoti.2012.06.002Guided electromagnetic waves propagating along one-dimensional arrays of dielectric spheres are studied. The quasi-periodic wave field is constructed as a superposition of vector spherical wavefunctions and then application of the boundary condition on the sphere surfaces leads to an infinite system of real linear algebraic equations. The vanishing of the determinant of the associated infinite matrix provides the condition for surface waves to exist and these are determined numerically after truncation of the infinite system. Dispersion curves are presented for a range of azimuthal modes and the effects of varying the sphere radius and electric permittivity are shown. We also demonstrate that a suitable truncation of the full system is precisely equivalent to the dipole approximation that has been used previously by other authors, in which the incident field on a sphere is approximated by its value at the centre of that sphere. © 2012 Elsevier B.V