14,391 research outputs found

    Manually operated elastomer heat pump

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    Device consisting of a rotating mechanism, a frame with multiple wide bands of rubber, and a fluid bath, demonstrates the feasibility of a human operated device capable of cooling or producing heat. This invention utilizes the basic thermodynamic properties of natural rubber

    Input Use and Incentives in the Caribbean Shrimp Fishery: The Case of the Trinidad and Tobago Fleet

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    This paper examines the economic factors that influence output in the Trinidad and Tobago shrimp fishery using a Generalized Leontief production function. Factors such as output prices and the use of inputs in the fishery are assessed. The artisanal and industrial fleets operate in a largely open-access fishery, which is seasonal. While shrimp is the main targeted species, various fish species are also targeted using gear modifications. It was found that for the artisanal shrimp trawl fleet in Trinidad and Tobago, effort, in terms of trip days, was estimated to have a significant effect on both shrimp and bycatch landings at almost similar levels. The relative price of the two species was not found to be significant, and no annual trends in the production of either was observed. However, the high season for shrimp landings, January to June, was found to have significant inverse effects on shrimp and bycatch landings.Generalized Leontief production function, effort, shrimp, Trinidad and Tobago., Community/Rural/Urban Development, Institutional and Behavioral Economics, International Development, Research Methods/ Statistical Methods, Q21, Q22, C33.,

    Study of heat sensitive radioisotopes for temperature measurement application Final report

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    Heat sensitive radioisotopes for temperature measurements in rocket nose cone

    Nonlinear quantum optical computing via measurement

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    We show how the measurement induced model of quantum computation proposed by Raussendorf and Briegel [Phys. Rev. Letts. 86, 5188 (2001)] can be adapted to a nonlinear optical interaction. This optical implementation requires a Kerr nonlinearity, a single photon source, a single photon detector and fast feed forward. Although nondeterministic optical quantum information proposals such as that suggested by KLM [Nature 409, 46 (2001)] do not require a Kerr nonlinearity they do require complex reconfigurable optical networks. The proposal in this paper has the benefit of a single static optical layout with fixed device parameters, where the algorithm is defined by the final measurement procedure.Comment: 14 pages, 4 figures, 4 table

    Ion collection by oblique surfaces of an object in a transversely-flowing strongly-magnetized plasma

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    The equations governing a collisionless obliquely-flowing plasma around an ion-absorbing object in a strong magnetic field are shown to have an exact analytic solution even for arbitrary (two-dimensional) object-shape, when temperature is uniform, and diffusive transport can be ignored. The solution has an extremely simple geometric embodiment. It shows that the ion collection flux density to a convex body's surface depends only upon the orientation of the surface, and provides the theoretical justification and calibration of oblique `Mach-probes'. The exponential form of this exact solution helps explain the approximate fit of this function to previous numerical solutions.Comment: Four pages, 2 figures. Submitted to Phys. Rev. Letter

    Phase Transitions in Ultra-Cold Two-Dimensional Bose Gases

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    We briefly review the theory of Bose-Einstein condensation in the two-dimensional trapped Bose gas and, in particular the relationship to the theory of the homogeneous two-dimensional gas and the Berezinskii-Kosterlitz-Thouless phase. We obtain a phase diagram for the trapped two-dimensional gas, finding a critical temperature above which the free energy of a state with a pair of vortices of opposite circulation is lower than that for a vortex-free Bose-Einstein condensed ground state. We identify three distinct phases which are, in order of increasing temperature, a phase coherent Bose-Einstein condensate, a vortex pair plasma with fluctuating condensate phase and a thermal Bose gas. The thermal activation of vortex-antivortex pair formation is confirmed using finite-temperature classical field simulations
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