6,442 research outputs found

    State Cooperative Councils: What are the Local Member Cooperatives Looking For?

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    State cooperative councils serve a valuable role for local cooperatives by providing services including education, legislative monitoring and lobbying, and promotion of the cooperative form of business. This paper outlines the specific challenges that state councils are experiencing in today's changing agribusiness environment. The results of a survey of members of the Colorado Cooperative Council are reported. Logit analysis is performed to identify the factors contributing to the cooperatives' satisfaction with the state council and the cooperatives' use of the council's services. The paper concludes with suggestions for action by state councils.Agribusiness,

    Energy levels and radiative rates for transitions in Fe V, Co VI and Ni VII

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    Energy levels, Land\'{e} gg-factors and radiative lifetimes are reported for the lowest 182 levels of the 3d4^4, 3d3^34s and 3d3^34p configurations of Fe~V, Co~VI and Ni~VII. Additionally, radiative rates (AA-values) have been calculated for the E1, E2 and M1 transitions among these levels. The calculations have been performed in a quasi-relativistic approach (QR) with a very large {\em configuration interaction} (CI) wavefunction expansion, which has been found to be necessary for these ions. Our calculated energies for all ions are in excellent agreement with the available measurements, for most levels. Discrepancies among various calculations for the radiative rates of E1 transitions in Fe~V are up to a factor of two for stronger transitions (f0.1f \geq 0.1), and larger (over an order of magnitude) for weaker ones. The reasons for these discrepancies have been discussed and mainly are due to the differing amount of CI and methodologies adopted. However, there are no appreciable discrepancies in similar data for M1 and E2 transitions, or the gg-factors for the levels of Fe~V, the only ion for which comparisons are feasible.Comment: This paper of 78 pages including 9 Tables will appear in ADNDT (2016

    Plasma properties and Stokes profiles during the lifetime of a photospheric magnetic bright point

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    Aims: to investigate the evolution of plasma properties and Stokes parameters in photospheric magnetic bright points using 3D magneto-hydrodynamical simulations and radiative diagnostics of solar granulation. Methods: simulated time-dependent radiation parameters and plasma properties were investigated throughout the evolution of a bright point. Synthetic Stokes profiles for the FeI 630.25 nm line were calculated, which allowed the evolution of the Stokes-I line strength and Stokes-V area and amplitude asymmetries to also be investigated. Results: our results are consistent with theoretical predictions and published observations describing convective collapse, and confirm this as the bright point formation process. Through degradation of the simulated data to match the spatial resolution of SOT, we show that high spatial resolution is crucial for the detection of changing spectro-polarimetric signatures throughout a magnetic bright point's lifetime. We also show that the signature downflow associated with the convective collapse process is reduced towards zero as the radiation intensity in the bright point peaks, due to the magnetic forces present restricting the flow of material in the flux tube.Comment: 14 pages, 12 figures, accepted to A&

    An assessment of Fe XX - Fe XXII emission lines in SDO/EVE data as diagnostics for high density solar flare plasmas using EUVE stellar observations

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    The Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory obtains extreme-ultraviolet (EUV) spectra of the full-disk Sun at a spectral resolution of ~1 A and cadence of 10 s. Such a spectral resolution would normally be considered to be too low for the reliable determination of electron density (N_e) sensitive emission line intensity ratios, due to blending. However, previous work has shown that a limited number of Fe XXI features in the 90-60 A wavelength region of EVE do provide useful N_e-diagnostics at relatively low flare densities (N_e ~ 10^11-10^12 cm^-3). Here we investigate if additional highly ionised Fe line ratios in the EVE 90-160 A range may be reliably employed as N_e-diagnostics. In particular, the potential for such diagnostics to provide density estimates for high N_e (~10^13 cm^-3) flare plasmas is assessed. Our study employs EVE spectra for X-class flares, combined with observations of highly active late-type stars from the Extreme Ultraviolet Explorer (EUVE) satellite plus experimental data for well-diagnosed tokamak plasmas, both of which are similar in wavelength coverage and spectral resolution to those from EVE. Several ratios are identified in EVE data which yield consistent values of electron density, including Fe XX 113.35/121.85 and Fe XXII 114.41/135.79, with confidence in their reliability as N_e-diagnostics provided by the EUVE and tokamak results. These ratios also allow the determination of density in solar flare plasmas up to values of ~10^13 cm^-3.Comment: 7 pages, 3 figures, 2 tables, MNRAS in pres

    Apollo 9 multiband photography experiment 5065 Interim post-flight calibration report

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    Camera and filter postflight spectrum analysis for Apollo 9 multiband photography experimen

    Energy levels and radiative rates for transitions in Cr-like Co IV and Ni V

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    We report calculations of energy levels and radiative rates (AA-values) for transitions in Cr-like Co IV and Ni V. The quasi-relativistic Hartree-Fock (QRHF) code is adopted for calculating the data although GRASP (general-purpose relativistic atomic structure package) and flexible atomic code (FAC) have also been employed for comparison purposes. No radiative rates are available in the literature to compare with our results, but our calculated energies are in close agreement with those compiled by NIST for a majority of the levels. However, there are discrepancies for a few levels of up to 3\%. The AA-values are listed for all significantly contributing E1, E2 and M1 transitions, and the corresponding lifetimes reported, although unfortunately no previous theoretical or experimental results exist to compare with our data.Comment: The paper will appear in ADNDT (2016) and in October 2015 on the we

    Two-stage fan. 3: Data and performance with rotor tip casing treatment, uniform and distorted inlet flows

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    A two stage fan with a 1st-stage rotor design tip speed of 1450 ft/sec, a design pressure ratio of 2.8, and corrected flow of 184.2 lbm/sec was tested with axial skewed slots in the casings over the tips of both rotors. The variable stagger stators were set in the nominal positions. Casing treatment improved stall margin by nine percentage points at 70 percent speed but decreased stall margin, efficiency, and flow by small amounts at design speed. Treatment improved first stage performance at low speed only and decreased second stage performance at all operating conditions. Casing treatment did not affect the stall line with tip radially distorted flow but improved stall margin with circumferentially distorted flow. Casing treatment increased the attenuation for both types of inlet flow distortion
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