86 research outputs found

    A social history of the Atholl estates 1685-1785

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    SIGLELD:D45264/83 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    Verslag van de dialogen over duurzame landbouw in 2006

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    In opdracht van de WOT Natuur & Milieu zijn in 2006 in totaal zeven dialogen georganiseerd door LEI, WING (Wageningen UR) en het Instituut voor Milieuvraagstukken IVM, Amsterdam. Dialogen zijn gehouden in zes sectoren: de varkens-, melkvee- en pluimveehouderij, de glastuinbouw, de akkerbouw en de opengrondsteelten. Daarnaast is een afsluitende, zevende, dialoog georganiseerd over thema’s gebaseerd op de uitkomsten van de voorafgaande zes sectordialogen. Dit werkdocument bevat het basismateriaal uit de dialoge

    Dialogen over verduurzaming van de Nederlandse landbouw : gestructureerde sectordialogen als onderdeel van een monitoringsmethodiek

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    Dit rapport beschrijft en analyseert een serie gestructureerde sectordialogen als onderdeel van een monitoringsmethodiek voor de verduurzaming van de landbouw. Deze dialogen zijn in 2006 in opdracht van het Ministerie van LNV georganiseerd met de volgende doelen: 1) Welke ambities hebben de verschillende sectoren op het gebied van het verduurzamen van de landbouw en 2) hoe vindt de sector dat zij er op dit moment voorstaat in haar ontwikkeling naar een duurzame landbouw? In een kritische reflectie wordt de kwaliteit en effectiviteit van de uitgevoerde sectordialogen behandeld. In een vergelijking met een kwantitatieve monitoringsmethodiek wordt de toegevoegde waarde van de dialogen als (aanvullend) onderdeel van een meer omvattende methodiek voor de monitoring van verduurzaming van de landbouw bediscussieerd. Trefwoorden: lerende monitoring, participatieve monitoring, dialogen, duurzame landbou

    Measurements of classical transport of fast ions

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    To study the fast-ion transport in a well controlled background plasma, a 3-cm diameter rf ion gun launches a pulsed, ~300 eV ribbon shaped argon ion beam parallel to or at 15°to the magnetic field in the Large Plasma Device (LAPD) [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)] at UCLA. The parallel energy of the beam is measured by a two-grid energy analyzer at two axial locations (z=0.32 m and z=6.4 m) from the ion gun in LAPD. The calculated ion beam slowing-down time is consistent to within 10% with the prediction of classical Coulomb collision theory using the LAPD plasma parameters measured by a Langmuir probe. To measure cross-field transport, the beam is launched at 15°to the magnetic field. The beam then is focused periodically by the magnetic field to avoid geometrical spreading. The radial beam profile measurements are performed at different axial locations where the ion beam is periodically focused. The measured cross-field transport is in agreement to within 15% with the analytical classical collision theory and the solution to the Fokker-Planck kinetic equation. Collisions with neutrals have a negligible effect on the beam transport measurement but do attenuate the beam current. © 2005 American Institute of Physics

    Measurements of interactions between waves and energetic ions in basic plasma experiments

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    To measure the transport of fast ions by various types of waves, complementary experiments are conducted in linear and toroidal magnetic fields in the large plasma device and the toroidal plasma experiment. Lithium sources that are immersed in the plasma provide the energetic ions. Spatial scans of collectors measure the transport. Techniques to find the beam and optimize the spatial sensitivity are described. Measurements of Coulomb scattering, resonant interaction with Alfven waves, and transport by drift-wave and interchange turbulence are summarized

    Energetic electron precipitation driven by electromagnetic ion cyclotron waves from ELFIN's low altitude perspective

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    We review comprehensive observations of electromagnetic ion cyclotron (EMIC) wave-driven energetic electron precipitation using data from the energetic electron detector on the Electron Losses and Fields InvestigatioN (ELFIN) mission, two polar-orbiting low-altitude spinning CubeSats, measuring 50-5000 keV electrons with good pitch-angle and energy resolution. EMIC wave-driven precipitation exhibits a distinct signature in energy-spectrograms of the precipitating-to-trapped flux ratio: peaks at 0.5 MeV which are abrupt (bursty) with significant substructure (occasionally down to sub-second timescale). Multiple ELFIN passes over the same MLT sector allow us to study the spatial and temporal evolution of the EMIC wave - electron interaction region. Using two years of ELFIN data, we assemble a statistical database of 50 events of strong EMIC wave-driven precipitation. Most reside at L=5-7 at dusk, while a smaller subset exists at L=8-12 at post-midnight. The energies of the peak-precipitation ratio and of the half-peak precipitation ratio (our proxy for the minimum resonance energy) exhibit an L-shell dependence in good agreement with theoretical estimates based on prior statistical observations of EMIC wave power spectra. The precipitation ratio's spectral shape for the most intense events has an exponential falloff away from the peak (i.e., on either side of 1.45 MeV). It too agrees well with quasi-linear diffusion theory based on prior statistics of wave spectra. Sub-MeV electron precipitation observed concurrently with strong EMIC wave-driven 1MeV precipitation has a spectral shape that is consistent with efficient pitch-angle scattering down to 200-300 keV by much less intense higher frequency EMIC waves. These results confirm the critical role of EMIC waves in driving relativistic electron losses. Nonlinear effects may abound and require further investigation
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