13,603 research outputs found

    An exploratory flight investigation of helicopter sling-load placements using a closed-circuit television as a pilot aid

    Get PDF
    Helicopter sling load operations have been limited during pick up and delivery of external cargo by the lack of precision achieved by the combination of pilot, helicopter, and sling load. Use of a closed circuit television as a pilot aid during sling load delivery and placement was documented along with additional cases representing procedures currently employed by military and commercial operators. Although an increase in pilot workload was noted when the television system was used, the results indicated a comparable level of performance for each test case

    Determination of MIC and Disk Diffusion Quality Control Guidelines for Meropenem–Vaborbactam, a Novel Carbapenem/Boronic Acid β-Lactamase Inhibitor Combination

    Get PDF
    Meropenem–vaborbactam is a carbapenem/cyclic boronic acid β-lactamase inhibitor combination primarily active against Gram-negative bacilli, including those harboring class A serine carbapenemases such as Klebsiella pneumoniae carbapenemase (KPC). A Clinical and Laboratory Standards Institute M23-A4 (Tier 2) quality control study established broth microdilution and disk diffusion ranges for reference strains. Two KPC-producing K. pneumoniae ATCC strains are recommended for quality control testing

    Communications systems technology assessment study. Volume 2: Results

    Get PDF
    The cost and technology characteristics are examined for providing special satellite services at UHF, 2.5 GHz, and 14/12 GHz. Considered are primarily health, educational, informational and emergency disaster type services. The total cost of each configuration including space segment, earth station, installation operation and maintenance was optimized to reduce the user's total annual cost and establish preferred equipment performance parameters. Technology expected to be available between now and 1985 is identified and comparisons made between selected alternatives. A key element of the study is a survey of earth station equipment updating past work in the field, providing new insight into technology, and evaluating production and test methods that can reduce costs in large production runs. Various satellite configurations were examined. The cost impact of rain attenuation at Ku-band was evaluated. The factors affecting the ultimate capacity achievable with the available orbital arc and available bandwidth were analyzed

    Optimal symmetric flight studies

    Get PDF
    Several topics in optimal symmetric flight of airbreathing vehicles are examined. In one study, an approximation scheme designed for onboard real-time energy management of climb-dash is developed and calculations for a high-performance aircraft presented. In another, a vehicle model intermediate in complexity between energy and point-mass models is explored and some quirks in optimal flight characteristics peculiar to the model uncovered. In yet another study, energy-modelling procedures are re-examined with a view to stretching the range of validity of zeroth-order approximation by special choice of state variables. In a final study, time-fuel tradeoffs in cruise-dash are examined for the consequences of nonconvexities appearing in the classical steady cruise-dash model. Two appendices provide retrospective looks at two early publications on energy modelling and related optimal control theory

    Density of bulk trap states in organic semiconductor crystals: discrete levels induced by oxygen in rubrene

    Full text link
    The density of trap states in the bandgap of semiconducting organic single crystals has been measured quantitatively and with high energy resolution by means of the experimental method of temperature-dependent space-charge-limited-current spectroscopy (TD-SCLC). This spectroscopy has been applied to study bulk rubrene single crystals, which are shown by this technique to be of high chemical and structural quality. A density of deep trap states as low as ~ 10^{15} cm^{-3} is measured in the purest crystals, and the exponentially varying shallow trap density near the band edge could be identified (1 decade in the density of states per ~25 meV). Furthermore, we have induced and spectroscopically identified an oxygen related sharp hole bulk trap state at 0.27 eV above the valence band.Comment: published in Phys. Rev. B, high quality figures: http://www.cpfs.mpg.de/~krellner

    Arkansas Wheat Cultivar Performance Tests 2010-2011

    Get PDF
    Wheat cultivar performance tests are conducted each year in Arkansas by the Arkansas Agricultural Experiment Station, Department of Crop, Soil and Environmental Sciences. The tests provide information to companies developing cultivars and/or marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating cultivar recommendations for small-grain producers

    The Surrender to God Scale: Psychometric Validation and Psychological Correlates

    Get PDF
    (1) Surrender to God (STG), is a construct which quantifies the extent to which an individual willingly relinquishes control to God. (2) An STG scale has been developed, yet remains unvalidated, as it relates to psychological constructs. (3) Utilizing undergraduate participants (N=249), we conducted a psychometric validation of the STG scale, and examined its potential relation with depression, anxiety, stress, and suicide ris

    New Constraints on Neutralino Dark Matter in the Supersymmetric Standard Model

    Full text link
    We investigate the prospects for neutralino dark matter within the Supersymmetric Standard Model (SSM) including the constraints from universal soft supersymmetry breaking and radiative breaking of the electroweak symmetry. The latter is enforced by using the one-loop Higgs effective potential which automatically gives the one-loop corrected Higgs boson masses. We perform an exhaustive search of the allowed five-dimensional parameter space and find that the neutralino relic abundance Ωχh02\Omega_\chi h^2_0 depends most strongly on the ratio ξ0≡m0/m1/2\xi_0\equiv m_0/m_{1/2}. For ξ0≫1\xi_0\gg1 the relic abundance is almost always much too large, whereas for ξ0≪1\xi_0\ll1 the opposite occurs. For ξ0∼1\xi_0\sim1 there are wide ranges of the remaining parameters for which Ωχ∼1\Omega_\chi\sim1. We also determine that m_{\tilde q}\gsim250\GeV and m_{\tilde l}\gsim100\GeV are necessary in order to possibly achieve Ωχ∼1\Omega_\chi\sim1. These lower bounds are much weaker than the corresponding ones derived previously when radiative breaking was {\it not} enforced.Comment: 12 pages plus 6 figures (not included), CERN-TH.6584/92, CTP-TAMU-56/92, UAHEP921

    Late Time Barium Cloud Striations and Their Possible Relationship to Equatorial Spread F

    Get PDF
    An active experiment has been conducted in space that allows a test for the theory of nonlinear development of striations in large barium clouds. The results are in excellent agreement with a computer simulation of the ExB instability reported by Scannapiecoe t al. (1976). The power law irregularity spectrum predicted by the theory and verified by the experiment is shown here to be due to wave steepeninga nd not_top lasmat urbulence.T he barium cloud resultsa re remarkably similar to bottomside equatorial spread F. A possible role of the E x B instability in bottomside equatorial spread F is discussed as a supplement to the Rayleigh-Taylor instability during the postsunset rise of the F layer and during anomalousp lasma uplifts which occur during geomagneticallya ctive period

    Crit II Electric, Magnetic, and Density Measurements Within an Ionizing Neutral Stream

    Get PDF
    Measurements from rocket borne sensors inside a high velocity neutral barium beam show a factor of six increasei n plasmad ensityi n a movingi onizingf ront. This region-wacso -locatedw ith intensef luctuatinge lectric fields( $E • 300m V/m) at frequenciewse llu ndert he lower hybrid frequency for a barium plasina. Large quasi-DC electric and magnetic field fluctuations were also detected with a large componento f the current and the electricf ield. parallelt o Bo. An Alfv6n wavew ith a finite electricf ield componentp arallel to the geomagneticfi eld was observed to propagatea longB o, wherei t wasd etectedb y ami nstrumented sub-payload
    • …
    corecore