2,541 research outputs found

    Nonlocality in Homogeneous Superfluid Turbulence

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    Simulating superfluid turbulence using the localized induction approximation in periodic bound- aries produces open-orbit vortices, which make superfluid turbulence unsustainable. Calculating with the fully nonlocal Biot-Savart law prevents the open-orbit state from forming, but also in- creases computation time. We use a truncated Biot-Savart integral to investigate the effects of nonlocality on homogeneous turbulence. We find that including the nonlocal interaction up to the average intervortex spacing prevents this open-orbit state from forming, yielding an accurate model of homogeneous superfluid turbulence with less computation time

    Demodulation system Patent

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    Development of demodulation system for removing amplitude modulation from two quadrature displaced data bearing signal

    The Invincible (1758) site: an integrated geophysical assessment

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    Chirp sub-bottom profiler and repeat sidescan sonar imaging of the Invincible wreck site (1758) in the Solent (U.K.), interpretation, and implications for management of the site

    Optimal Processing of Marine High-Resolution Seismic Reflection (Chirp) Data

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    Chirp frequency-modulated (FM) systems offer deterministic, repeatable source-signatures for high-resolution, normal incidence marine seismic reflection data acquisition. An optimal processing sequence for uncorrelated Chirp data is presented to demonstrate the applicability of some conventional seismic reflection algorithms to high-resolution data sets, and to emphasise the importance of a known source-signature. An improvement of greater than 60dB in the signal- to-noise ratio is realised from correlating the FM reflection data with the transmitted pulse. Interpretability of ringy deconvolved data is enhanced by the calculation of instantaneous amplitudes. The signal-to-noise ratio and lateral reflector continuity are both improved by the application of predictive filters whose effectiveness are aided by the repeatability of the Chirp source.<br/

    Vortex Simulations on a 3-Sphere

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    We generate vortex tangles using a Hopf flow on a 3-sphere, in place of the standard torus defined by periodic boundary conditions. These tangles are highly anisotropic, with vortices tending to align along the flow direction. Standard power law dependences change accordingly from their values in more isotropic tangles. The line length density ⟨L⟩\langle L\rangle is proportional to vns1.28v_{ns}^{1.28}, where vnsv_{ns} is the drive velocity, and the reconnection rate depends roughly on ⟨L⟩2\langle L\rangle^2. We also discuss the effect of the full Biot-Savart law versus the local induction approximation (LIA). Under LIA the tangle collapses so that all vortices are nearly aligned with a single flow line, in sharp contrast to the torus where they become perpendicular to the driving velocity. Finally we present a few torus simulations with a helical velocity field, which in some ways resembles the 3-sphere flow

    Irish Provincial Printing Prior to 1701

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    Sex Offender Treatment Project: Literature Review

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    A comprehensive literature review on recidivism by and the treatment of sex offenders.Alaska Department of CorrectionsAcknowledgements / Introduction / Recidivism / Treatment — Voluntary Vs. Involuntary, Treated Vs. Untreated / Treatment — Types, Levels, Evolution, Relapse Prevention and Cost/Benefit Analysis / Treatment and Recidivism as it Relates to Various Types of Sexual Offenders / Other Factors Possibly Involved in Reoffense Potential / Conclusion / Bibliograph

    Economic Shocks and Crime: Evidence from the Brazilian Trade Liberalization

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    This paper studies the effect of changes in economic conditions on crime. We exploit the 1990s trade liberalization in Brazil as a natural experiment generating exogenous shocks to local economies. We document that regions exposed to larger tariff reductions experienced a temporary increase in crime following liberalization. Next, we investigate through what channels the trade-induced economic shocks may have affected crime. We show that the shocks had significant effects on potential determinants of crime, such as labor market conditions, public goods provision, and income inequality. We propose a novel framework exploiting the distinct dynamic responses of these variables to obtain bounds on the effect of labor market conditions on crime. Our results indicate that this channel accounts for 75 to 93 percent of the effect of the trade-induced shocks on crime
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