324 research outputs found

    Exploring the hidden interior of the Earth with directional neutrino measurements

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    Roughly 40% of the Earth's total heat flow is powered by radioactive decays in the crust and mantle. Geo-neutrinos produced by these decays provide important clues about the origin, formation and thermal evolution of our planet, as well as the composition of its interior. Previous measurements of geo-neutrinos have all relied on the detection of inverse beta decay reactions, which are insensitive to the contribution from potassium and do not provide model-independent information about the spatial distribution of geo-neutrino sources within the Earth. Here we present a method for measuring previously unresolved components of Earth's radiogenic heating using neutrino-electron elastic scattering and low-background, direction-sensitive tracking detectors. We calculate the exposures needed to probe various contributions to the total geo-neutrino flux, specifically those associated to potassium, the mantle and the core. The measurements proposed here chart a course for pioneering exploration of the veiled inner workings of the Earth.Comment: 18 pages, 11 figures, 8 table

    DRAFT 2004 Cruise Report PROGRAMME: RV CEFAS Endeavour: CRUISE 14

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    Internal tides in a dendritic submarine canyon

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    Submarine canyons are a common geomorphological feature along continental slopes worldwide and often found to be ‘hotspots’ of internal tide activity. However, the majority of well-studied submarine canyons are simple linear incisions or have meandering morphology; internal tide energetics in branching (dendritic) canyons has not previously been investigated. Here we present a high-resolution (500-m) numerical modelling study of the internal tide within Whittard Canyon, a large, dendritic submarine canyon system that incises the Celtic Sea continental slope. A modified version of the Princeton Ocean Model is used to simulate the M2 (semidiurnal) internal tide in the Whittard Canyon region, verified against a hydrographic dataset collected by an autonomous ocean glider. Much of the internal tide energy entering Whittard Canyon originates to the southeast, along the Celtic Sea shelf break. Internal tide generation also occurs within the canyon itself, but is in part compensated by areas of negative energy conversion. Depth-integrated internal tide energy fluxes exceed 8 kW m−1 in the eastern limb of the canyon. The internal tide is topographically steered through the major limbs and along-canyon energy flux is bottom intensified, suggesting topographic focusing. The down canyon extent of bottom intensification closely corresponds to the point that along-canyon slope becomes near-critical to the semidiurnal internal tide. Energetically, the multiple limbs of Whittard Canyon behave differently, some are net sources of internal tide energy whilst others are net sinks. Internal tide energy dissipation also varies between the canyon limbs; bulk dissipation rates are 2.1-7.7 × 10−8 W kg−1 . In addition, the effect of bathymetric resolution on internal tide generation and propagation is investigated by progressively smoothing the model domain. Decreasing the bathymetric resolution reduces internal tide generation and energy dissipation in both Whittard Canyon and the model domain as a whole, however, internal tide energy flux into the canyon is not consistently changed. At least 1.5-km resolution bathymetry is required to adequately resolve the semidiurnal internal tide field in this region of complex topography

    Digital Yoknapatawpha: A Progress Report on a Work in Progress

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    Box lunch available. Underway since 2011, the NEH-sponsored Digital Yoknapatawpha project is a collaboration of over two dozen Faulkner scholars from around the country and the world and a team of technologists at the University of Virginia. It is being designed to provide new modes of exploring and appreciating all the fictions that Faulkner set in his mythical county. At this presentation we’ll showcase the current state of the project, with special emphasis on its usefulness as both a scholarly and a pedagogical resource. We’ll display how it works, how it can assist with critical research, and how it can help teachers and students in the classroom. We also hope to enlist some additional collaborators, especially teachers who are willing to try it in their own classrooms. We’re anxious to learn how it works with real users as we continue to develop it

    State of Maine\u27s Beaches in 2013

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    The 2013 State of Maine’s Beaches Report is the 4th report in a consecutive series of reports coinciding with the Maine Beaches Conference from 2007, 2009, and 2011. The purpose of the report is to summarize major observed morphologic characteristics and changes of Maine beaches that are monitored as part of the State of Maine Beach Profiling Project (SMBPP, Maine Sea Grant Extension, 2003). The SMBPP utilizes trained volunteers to collect monthly beach profiles which start at a known point or benchmark (usually in the frontal dune or in a seawall) and continue shore-perpendicular to roughly the low water line. Fixed starting locations are used with the Emery Method of beach profiling (Emery, 1961). Data collected is entered by volunteers into an online database, where it is accessible for outside researchers (Maine Shore Stewards, 2007). The SMBPP is funded and managed by combined efforts of the Maine Geological Survey, University of Maine, Maine Sea Grant, and Maine Coastal Program

    Reanalysis for MSFD

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    This report gives a brief summary of progress to date in Task 8.6 of AtlantOS. At the time of writing (September 2017) results are being written up in a paper for the peer-reviewed literature (Tinker et al., in prep.), expected to be submitted in Autumn 2017. To maintain the confidentiality of the peer review process only a brief summary of the results of the paper are presented here. The paper will be linked to this deliverable report as soon as it is published. In the mean time access to the paper while under review may be requested from the lead authors of this report at [email protected] and [email protected]

    Neutrino Mixing Discriminates Geo-reactor Models

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    Geo-reactor models suggest the existence of natural nuclear reactors at different deep-earth locations with loosely defined output power. Reactor fission products undergo beta decay with the emission of electron antineutrinos, which routinely escape the earth. Neutrino mixing distorts the energy spectrum of the electron antineutrinos. Characteristics of the distorted spectrum observed at the earth's surface could specify the location of a geo-reactor, discriminating the models and facilitating more precise power measurement. The existence of a geo-reactor with known position could enable a precision measurement of the neutrino oscillation parameter delta-mass-squared.Comment: 6 pages, 6 figures, minor revisions, submitted to PR
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