8,255 research outputs found

    Analysis, design, and test of acoustic treatment in a laboratory inlet duct

    Get PDF
    A suppression prediction program based on the method of modal analysis for spinning mode propagation in a circular duct was used in the analytical design of optimized, multielement, Kevlar bulk-absorber treatment configurations for an inlet duct. The NASA-Langley ANRL anechoic chamber using the spinning mode synthesizer as a sound source was used to obtain in-duct spinning mode measurements, radial mode measurements, and far-field traverses, as well as aerodynamic measurements. The measured suppression values were compared to predicted values, using the in-duct, forward-traveling, radial-mode content as the source for the prediction. The performance of the treatment panels was evaluated from the predicted and measured data. Although experimental difficulties were encountered at the design condition, sufficient information was obtained to confirm the expectation that it is the panel impedance components which are critical to suppression at a single frequency, not the particular construction materials. The agreement obtained between measurement and prediction indicates that the analytical program can be used as an accurate, reliable, and useful design tool

    The dimpling in the CuO_2 planes of YBa_2Cu_3O_x (x=6.806-6.984, T=20-300 K) measured by yttrium EXAFS

    Full text link
    The dimpling of the CuO_2 planes (spacing between the O2,3 and Cu2 layers) in YBa_2Cu_3O_x has been measured as a function of oxygen concentration and temperature by yttrium x-ray extended-fine-structure spectroscopy (EXAFS). The relative variations of the dimpling with doping (x=6.806-6.984) and temperature (20-300 K) are weak (within 0.05 AA), and arise mainly from displacements of the Cu2 atoms off the O2,3 plane towards Ba. The dimpling appears to be connected with the transition from the underdoped to the overdoped regimes at x=6.95, and with a characteristic temperature in the normal state, T*=150 K.Comment: 6 pages, 2 ps figs, LaTEX, Elsevier Elsart styl

    The Beneficial Impact of Sorting Heavy Cattle at Re-Implant

    Get PDF
    This research examined a simple sorting strategy to reduce the prevalence of heavyweight carcass discounts. Cattle that were identified and sorted off at re-implant had a reduced prevalence of heavyweight carcasses versus unsorted cattle. Re-implant sorting was profitable at pen average in-weights of 800 pounds or less.cattle, fed cattle marketing, cattle sorting, formula marketing, Farm Management, Livestock Production/Industries, Marketing, Q11, Q16, M31,

    Sensitivity of an image plate system in the XUV (60 eV < E < 900 eV)

    Full text link
    Phosphor imaging plates (IPs) have been calibrated and proven useful for quantitative x-ray imaging in the 1 to over 1000 keV energy range. In this paper we report on calibration measurements made at XUV energies in the 60 to 900 eV energy range using beamline 6.3.2 at the Advanced Light Source at Lawrence Berkeley National Laboratory. We measured a sensitivity of ~25 plus or minus 15 counts/pJ over the stated energy range which is compatible with the sensitivity of Si photodiodes that are used for time-resolved measurements. Our measurements at 900 eV are consistent with the measurements made by Meadowcroft et al. at ~1 keV.Comment: 7 pages, 2 figure

    QCD sum rules for the anti-charmed pentaquark

    Full text link
    We present a QCD sum rule analysis for the anti-charmed pentaquark state with and without strangeness. While the sum rules for most of the currents are either non-convergent or dominated by the DNDN continuum, the one for the non-strange pentaquark current composed of two diquarks and an antiquark, is convergent and has a structure consistent with a positive parity pentaquark state after subtracting out the DNDN continuum contribution. Arguments are presented on the similarity between the result of the present analysis and that based on the constituent quark models, which predict a more stable pentaquark states when the antiquark is heavy.Comment: 19 pages, 8 figures, REVTex, revised version,new figures added and references update

    Antiferroquadrupolar Order in the Magnetic Semiconductor TmTe

    Full text link
    The physical properties of the antiferroquadrupolar state occurring in TmTe below TQ=1.8 K have been studied using neutron diffraction in applied magnetic fields. A field-induced antiferromagnetic component k = (1/2,1/2,1/2) is observed and, from its magnitude and direction for different orientations of H, an O(2,2) quadrupole order parameter is inferred. Measurements below TN ~= 0.5 K reveal that the magnetic structure is canted, in agreement with theoretical predictions for in-plane antiferromagnetism. Complex domain repopulation effects occur when the field is increased in the ordered phases, with discontinuities in the superstructure peak intensities above 4 T.Comment: 6 pages, 6 figures, Presented at the International Conference on Strongly Correlated Electrons with Orbital Degrees of Freedom (ORBITAL 2001), September 11-14, 2001 (Sendai, JAPAN). To appear in: Journal of the Physical Society of Japan (2002

    Galactic Cosmic Ray Origins and OB Associations: Evidence from SuperTIGER Observations of Elements 26_{26}Fe through 40_{40}Zr

    Get PDF
    We report abundances of elements from 26_{26}Fe to 40_{40}Zr in the cosmic radiation measured by the SuperTIGER (Trans-Iron Galactic Element Recorder) instrument during 55 days of exposure on a long-duration balloon flight over Antarctica. These observations resolve elemental abundances in this charge range with single-element resolution and good statistics. These results support a model of cosmic-ray origin in which the source material consists of a mixture of 19−6+11^{+11}_{-6}\% material from massive stars and ∌\sim81\% normal interstellar medium (ISM) material with solar system abundances. The results also show a preferential acceleration of refractory elements (found in interstellar dust grains) by a factor of ∌\sim4 over volatile elements (found in interstellar gas) ordered by atomic mass (A). Both the refractory and volatile elements show a mass-dependent enhancement with similar slopes.Comment: 9 pages, 12 figures, 2 tables, accepted by Ap

    Maggot Debridement Therapy in the Treatment of Footrot and Foot Scald in Sheep

    Full text link
    In sheep with acute and chronic interdigital skin inflammation, maggot therapy was used for the debridement and speeding up the healing process. Sheep were housed at the university farm ZemplĂ­nska Teplica and before using maggot therapy, they were unsuccessfully treated by a footbath containing 10% copper sulphate and topical application of oxytetracycline solution in alcohol. Six non-pregnant Valachian sheep between two to four years of age, weighing 43 to 57 kg were treated with maggots of Lucilia sericata (Meigen) (Diptera: Calliphoridae). The larval population should be 8-12 per square centimetre of wound, but all affected tissues were trimmed away before their application. The effect of a single application for 3-6 days was evaluated. Debridement was rapid and selective. The treatment was well tolerated by animals. New layers of healthy tissue were formed over the wounds. It was observed that maggots of L. sericata are capable of cleaning the wounds after single application
    • 

    corecore