23,204 research outputs found

    Endless tape cartridge Patent

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    Tape cartridge with high capacity storage of endless-loop magnetic tap

    An infrared proper motion study of the Orion bullets

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    We report the first IR proper motion measurements of the Herbig-Haro objects in the Orion Molecular Cloud--One using a four-year time baseline. The [Fe II] emitting bullets are moving of order 0.08 arcsec per year, or at about 170 \kms. The direction of motion is similar to that inferred from their morphology. The proper motions of \h2 emitting wakes behind the [Fe II] bullets, and of newly found \h2 bullets, are also measured. \h2 bullets have smaller proper motion than [Fe II] bullets, while \h2 wakes with leading [Fe II] bullets appear to move at similar speeds to their associated bullets. A few instances of variability in the emission can be attributed to dense, stationary clumps in the ambient cloud being overrun, setting up a reverse--oriented bullet. Differential motion between [Fe II] bullets and their trailing \h2 wakes is not observed, suggesting that these are not separating, and also that they have reached a steady--state configuration over at least 100 years. The most distant bullets have, on average, larger proper motions, but are not consistent with free expansion. Nevertheless an impulsive, or short--lived (≪\ll 1,000 years) duration for their origin seems likely.Comment: 9 pages, 8 figure

    ECONOMIC AND ENVIRONMENTAL BENEFITS OF VARIABLE RATE APPLICATION OF NITROGEN TO CORN FIELDS: ROLE OF VARIABILITY AND WEATHER

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    The use of meta-response functions based on EPIC-generated data resulted in comparisons between variable (VRAT) and uniform rate application technologies for 36 simulated fields. VRAT was more profitable and less nitrogen was lost to the environment in most cases. When spatial variability was small, uniform rate application techniques were adopted. However, when nitrogen use is restricted, VRAT is used on all simulated fields.Precision farming, site-specific farming, spatial variability, nitrogen restriction, rainfall, EPIC, crop growth simulation model, meta-response functions, Environmental Economics and Policy, Research and Development/Tech Change/Emerging Technologies, Resource /Energy Economics and Policy,

    “This feels like the start of something” — Storying the 2010 Exeter Occupation

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    This is the final version. Available from the University of British Columbia, Okanagan via the link in this recordThe University of Exeter was home to a student led occupation in November and December 2010. The occupation was a protest against education and public sector cuts and the rise in student tuition fees. It also became a site for a progressive re-presentation of the university, with the temporary space of the Exeter Free University, a publically accessible pedagogical space within the heart of the neoliberal university. This intervention emerged from a collaborative writing workshop within the Exeter Free University. Here, the storying (or, perhaps, storifying) of the Exeter Occupation is re-presented through the writing of the occupation, created at the time, in and through the emerging spaces of protest, radical pedagogy, and collective creativity. We mediate the unfolding dialogues but allow the material to speak for itself, to unfold and tell the story

    ASSESSING SPATIAL BREAK-EVEN VARIABILITY IN FIELDS WITH TWO OR MORE MANAGEMENT ZONES

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    Farmers are interested in knowing whether applying inputs at variable rates across a field is economically viable. The answer depends on the crop, the input, their prices, the cost of variable rate technology (VRT) versus uninform rate technology (URT), and the spatial and yield response variability within each field. Methods were investigated for determining the range of spatial variability over which the return to VRT covers its additional cost compared with URT in fields with multiple management zones. Models developed in this article, or variants thereof, could be used to help farmers make the VRT adoption decision.management zones, nitrogen, precision farming, site-specific management, spatial break-even variability proportions, spatial variability, variable rate technology, yield response variability, Farm Management,

    Kinetic step bunching during surface growth

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    We study the step bunching kinetic instability in a growing crystal surface characterized by anisotropic diffusion. The instability is due to the interplay between the elastic interactions and the alternation of step parameters. This instability is predicted to occur on a vicinal semiconductor surface Si(001) or Ge(001) during epitaxial growth. The maximal growth rate of the step bunching increases like F4F^{4}, where FF is the deposition flux. Our results are complemented with numerical simulations which reveals a coarsening behavior on the long time for the nonlinear step dynamics.Comment: 4 pages, 6 figures, submitted to PR

    EVALUATING THE RETURNS TO VARIABLE RATE NITROGEN APPLICATION

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    Potential benefits of variable rate nitrogen application are illustrated and information needs identified. Lower costs of precision farming services, higher crop prices, and greater divergence in yield response potentials across management zones reduce the spatial variability required for profitable variable rate application. Information needs include identification and measurement of management zones within a field and estimation of management zone yield response functions, crop and input prices, and the cost of precision farming services.production economics, management zones, nitrogen, precision farming, spatial break-even variability proportions, variable rate applications, yield response variability, Crop Production/Industries,
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