35,162 research outputs found

    An evaluation: The potential of discarded tires as a source of fuel

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    The destructive distillation of rubber tire samples was studied by thermogravimetry, differential scanning calorimetry, combustion calorimetry, and mass spectroscopy. The decomposition reaction was found to be exothermic and produced a mass loss of 65 percent. The gas evolution curves that were obtained indicate that a variety of organic materials are evolved simultaneously during the decomposition of the rubber polymer

    Classical Sphaleron Rate on Fine Lattices

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    We measure the sphaleron rate for hot, classical Yang-Mills theory on the lattice, in order to study its dependence on lattice spacing. By using a topological definition of Chern-Simons number and going to extremely fine lattices (up to beta=32, or lattice spacing a = 1 / (8 g^2 T)) we demonstrate nontrivial scaling. The topological susceptibility, converted to physical units, falls with lattice spacing on fine lattices in a way which is consistent with linear dependence on aa (the Arnold-Son-Yaffe scaling relation) and strongly disfavors a nonzero continuum limit. We also explain some unusual behavior of the rate in small volumes, reported by Ambjorn and Krasnitz.Comment: 14 pages, includes 5 figure

    Design Criteria for Zero Leakage Connectors for Launch Vehicles. Mathematical Model of Interface Sealing Phenomenon, Volume 2 Final Report

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    Mathematical model of interface sealing phenomenon in determining design criteria for zero leakage connectors for launch vehicle

    Generating entangled atom-photon pairs from Bose-Einstein condensates

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    We propose using spontaneous Raman scattering from an optically driven Bose-Einstein condensate as a source of atom-photon pairs whose internal states are maximally entangled. Generating entanglement between a particle which is easily transmitted (the photon) and one which is easily trapped and coherently manipulated (an ultracold atom) will prove useful for a variety of quantum-information related applications. We analyze the type of entangled states generated by spontaneous Raman scattering and construct a geometry which results in maximum entanglement

    Transfer or Redemption for a Withdrawing Partner: An Indifference Econometric Decision Model Built on the Position Improvement Equilibrium ( PIE ) Concept

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    The preferred way for a withdrawing partner to leave a partnership is normally thought to be by way of redemption under Internal Revenue Code Section 736 rather than as a transfer under Section 741 The advantage to the continuing partnership lies in the deductability of the payment to the withdrawing partner for goodwill. The withdrawing partner benefits from a higher exchange price, increased by the tax benefits of redemption treatment. However, the following three factors tilt the preference back toward a 741 transfer for both parties: individual obligation of portions of the exchange price, with additional basis, goodwill negotiations and safeguarding of the optional basis adjustment. To allow for proper consideration of these factors, indifference equations are proposed which produce an exchange price that makes 741 as advantageous to the dominant party as 736. These equations constitute a dynamic interactive econometric model for finding a position improvement equilibrium ( PIE ) indifference model that provides an incisive decision tool. This model takes graduated tax brackets into consideration, heightening its value as a decision tool

    Entanglement between photons and atoms coupled out from a Bose-Einstein-Condensate

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    We study the limitations to the relative number squeezing between photons and atoms coupled out from a homogeneous Bose-Einstein-Condensate. We consider the coupling between the translational atomic states by two photon Bragg processes, with one of the photon modes involved in the Bragg process in a coherent state, and the other initially unpopulated. We start with an interacting Bose- condensate at zero temperature and compute the time evolution for the system. We study the squeezing, i.e. the variance of the occupation number difference between the second photon and the atomic c.m. mode. We discuss how collisions between the atoms and photon rescattering affect the degree of squeezing which may be reached in such experiments.Comment: 4 pages RevTeX, 3 figure

    Coherent phonon scattering effects on thermal transport in thin semiconductor nanowires

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    The thermal conductance by phonons of a quasi-one-dimensional solid with isotope or defect scattering is studied using the Landauer formalism for thermal transport. The conductance shows a crossover from localized to Ohmic behavior, just as for electrons, but the nature of this crossover is modified by delocalization of phonons at low frequency. A scalable numerical transfer-matrix technique is developed and applied to model quasi-one-dimensional systems in order to confirm simple analytic predictions. We argue that existing thermal conductivity data on semiconductor nanowires, showing an unexpected linear dependence, can be understood through a model that combines incoherent surface scattering for short-wavelength phonons with nearly ballistic long-wavelength phonons. It is also found that even when strong phonon localization effects would be observed if defects are distributed throughout the wire, localization effects are much weaker when defects are localized at the boundary, as in current experiments.Comment: 13 page
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