5,637 research outputs found

    Efficient Computation of Power, Force, and Torque in BEM Scattering Calculations

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    We present concise, computationally efficient formulas for several quantities of interest -- including absorbed and scattered power, optical force (radiation pressure), and torque -- in scattering calculations performed using the boundary-element method (BEM) [also known as the method of moments (MOM)]. Our formulas compute the quantities of interest \textit{directly} from the BEM surface currents with no need ever to compute the scattered electromagnetic fields. We derive our new formulas and demonstrate their effectiveness by computing power, force, and torque in a number of example geometries. Free, open-source software implementations of our formulas are available for download online

    A Method of Utilizing Accounting Records for Nurseries Producing Field Grown Stock

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    Exact date of bulletin unknown.PDF pages: 1

    Computation of Casimir Interactions between Arbitrary 3D Objects with Arbitrary Material Properties

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    We extend a recently introduced method for computing Casimir forces between arbitrarily--shaped metallic objects [M. T. H. Reid et al., Phys. Rev. Lett._103_ 040401 (2009)] to allow treatment of objects with arbitrary material properties, including imperfect conductors, dielectrics, and magnetic materials. Our original method considered electric currents on the surfaces of the interacting objects; the extended method considers both electric and magnetic surface current distributions, and obtains the Casimir energy of a configuration of objects in terms of the interactions of these effective surface currents. Using this new technique, we present the first predictions of Casimir interactions in several experimentally relevant geometries that would be difficult to treat with any existing method. In particular, we investigate Casimir interactions between dielectric nanodisks embedded in a dielectric fluid; we identify the threshold surface--surface separation at which finite--size effects become relevant, and we map the rotational energy landscape of bound nanoparticle diclusters

    The importance of choosing attractors for optimizing chaotic communications

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    Fluctuating surface-current formulation of radiative heat transfer: theory and applications

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    We describe a novel fluctuating-surface current formulation of radiative heat transfer between bodies of arbitrary shape that exploits efficient and sophisticated techniques from the surface-integral-equation formulation of classical electromagnetic scattering. Unlike previous approaches to non-equilibrium fluctuations that involve scattering matrices---relating "incoming" and "outgoing" waves from each body---our approach is formulated in terms of "unknown" surface currents, laying at the surfaces of the bodies, that need not satisfy any wave equation. We show that our formulation can be applied as a spectral method to obtain fast-converging semi-analytical formulas in high-symmetry geometries using specialized spectral bases that conform to the surfaces of the bodies (e.g. Fourier series for planar bodies or spherical harmonics for spherical bodies), and can also be employed as a numerical method by exploiting the generality of surface meshes/grids to obtain results in more complicated geometries (e.g. interleaved bodies as well as bodies with sharp corners). In particular, our formalism allows direct application of the boundary-element method, a robust and powerful numerical implementation of the surface-integral formulation of classical electromagnetism, which we use to obtain results in new geometries, including the heat transfer between finite slabs, cylinders, and cones

    Transformation Optics scheme for two-dimensional materials

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    Two dimensional optical materials, such as graphene can be characterized by a surface conductivity. So far, the transformation optics schemes have focused on three dimensional properties such as permittivity ϵ\epsilon and permeability μ\mu. In this paper, we use a scheme for transforming surface currents to highlight that the surface conductivity transforms in a way different from ϵ\epsilon and μ\mu. We use this surface conductivity transformation to demonstrate an example problem of reducing scattering of plasmon mode from sharp protrusions in graphene

    Examining corporate blameworthiness in relation to federal organizational sentencing for probation and corporate monitors.

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    Organizations that have benefitted from the commission of federal crimes committed by their employees may be sentenced to federal criminal penalties. Two of these potential penalties include probation and the requirement to implement a corporate monitor. The federal guidelines provide suggestions for sentencing probation that echo the theoretical focal concern of blameworthiness. This research used eight years of United States Sentencing Commission data covering 2011 to 2018 (n= 1,224) to examine if organizations were being sentenced to probation and monitoring consistent with the federal guidelines and focal concern of blameworthiness. The study examined nine potential measures of blameworthiness and two key criminal offenses representing protection of the community. The results revealed no significant findings for blameworthiness for probation but some significance for the type of offense, showing that protection of the community is more predictive of being sentenced to probation than any measure of blameworthiness. For corporate monitoring, the only significant finding was that criminal purpose organizations were more likely to be sentenced to monitoring. These results are discussed in terms of policy implications, limitations, and future research
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