2,692 research outputs found

    Preliminary system design study for a digital fly-by-wire flight control system for an F-8C aircraft

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    The design of a fly-by-wire control system having a mission failure probability of less than one millionth failures per flight hour is examined. Emphasis was placed on developing actuator configurations that would improve the system performance, and consideration of the practical aspects of sensor/computer and computer/actuator interface implementation. Five basic configurations were defined as appropriate candidates for the F-8C research aircraft. Options on the basic configurations were included to cover variations in flight sensors, redundancy levels, data transmission techniques, processor input/output methods, and servo actuator arrangements. The study results can be applied to fly by wire systems for transport aircraft in general and the space shuttle

    X ray sensitive area detection device

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    A radiation sensitive area detection device is disclosed which comprises a phosphor-containing film capable of receiving and storing an image formed by a pattern of incoming x rays, UV, or other radiation falling on the film. The device is capable of fluorescing in response to stimulation by a light source in a manner directly proportional to the stored radiation pattern. The device includes: (1) a light source capable of projecting light or other appropriate electromagnetic wave on the film so as to cause it to fluoresce; (2) a means to focus the fluoresced light coming from the phosphor-containing film after light stimulation; and (3) at least one charged coupled detector or other detecting element capable of receiving and digitizing the pattern of fluoresced light coming from the phosphor-containing film. The device will be able to generate superior x ray images of high resolution from a crystal or other sample and will be particularly advantageous in that instantaneous near-real-time images of rapidly deteriorating samples can be obtained. Furthermore, the device can be made compact and sturdy, thus capable of carrying out x ray or other radiation imaging under a variety of conditions, including those experienced in space

    Postimpact deformation associated with the late Eocene Chesapeake Bay impact structure in southeastern Virginia

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    Upper Cenozoic strata covering the Chesapeake Bay impact structure in southeastern Virginia record intermittent differential movement around its buried rim. Miocene strata in a graben detected by seismic surveys on the York River exhibit variable thickness and are deformed above the crater rim. Fan-like interformational and intraformational angular unconformities within Pliocene–Pleistocene strata, which strike parallel to the crater rim and dip2°–3° away from the crater center, indicate that deformation and deposition were synchronous.Concentric, large-scale crossbedded, bioclastic sand bodies of Pliocene age within ~20 km of the buried crater rim formed on offshore shoals, presumably as subsiding listric slump blocks rotated near the crater rim

    Genome of Drosophila suzukii, the spotted wing drosophila.

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    Drosophila suzukii Matsumura (spotted wing drosophila) has recently become a serious pest of a wide variety of fruit crops in the United States as well as in Europe, leading to substantial yearly crop losses. To enable basic and applied research of this important pest, we sequenced the D. suzukii genome to obtain a high-quality reference sequence. Here, we discuss the basic properties of the genome and transcriptome and describe patterns of genome evolution in D. suzukii and its close relatives. Our analyses and genome annotations are presented in a web portal, SpottedWingFlyBase, to facilitate public access

    ROWS wave spectral data collected in SAXON-FPN, November 1990

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    High-resolution directional wave spectra obtained with the NASA Ku-band radar ocean wave spectrometer (ROWS) on the Naval Research Laboratory P-3 aircraft during SAXON-FPN (SAR and X-Band Ocean Nonlinearities Experiment-Forschungsplattform Nordsee) experiments in the North Sea in November 1990 are presented. This experiment was the first in which the ROWS was operated with its new pc-based high-speed digital data acquisition system

    Emissivity Results on High Temperature Coatings for Refractory Composite Materials

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    The directional emissivity of various refractory composite materials considered for application for reentry and hypersonic vehicles was investigated. The directional emissivity was measured at elevated temperatures of up to 3400 F using a directional spectral radiometric technique during arc-jet test runs. A laboratory-based relative total radiance method was also used to measure total normal emissivity of some of the refractory composite materials. The data from the two techniques are compared. The paper will also compare the historical database of Reinforced Carbon-Carbon emissivity measurements with emissivity values generated recently on the material using the two techniques described in the paper

    Space Tethers: Design Criteria

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    This document is prepared to provide a systematic process for the selection of tethers for space applications. Criteria arc provided for determining the strength requirement for tether missions and for mission success from tether severing due to micrometeoroids and orbital debris particle impacts. Background information of materials for use in space tethers is provided, including electricity-conducting tethers. Dynamic considerations for tether selection is also provided. Safety, quality, and reliability considerations are provided for a tether project

    Effect of growth-promoting technologies on Longissimus lumborum muscle fiber morphometrics, collagen solubility, and cooked meat tenderness

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    Citation: Ebarb, S. M., Drouillard, J. S., Maddock-Carlin, K. R., Phelps, K. J., Vaughn, M. A., Burnett, D. D., . . . Gonzalez, J. M. (2016). Effect of growth-promoting technologies on Longissimus lumborum muscle fiber morphometrics, collagen solubility, and cooked meat tenderness. Journal of Animal Science, 94(2), 869-881. doi:10.2527/jas2015-9888The objective of the study was to examine the effect of growth-promoting technologies (GP) on Longissimus lumborum steak tenderness, muscle fiber cross-sectional area (CSA), and collagen solubility. Crossbred feedlot heifers (n = 33; initial BW 464 +/- 6 kg) were blocked by BW and assigned to 1 of 3 treatments: no GP (CON; n = 11); implant, no zilpaterol hydrochloride (IMP; n = 11); implant and zilpaterol hydrochloride (COMBO; n = 11). Heifers assigned to receive an implant were administered Component TE-200 on d 0 of the study, and the COMBO group received 8.3 mg/kg DM of zilpaterol hydrochloride for the final 21 d of feeding with a 3 d withdrawal period. Following harvest, strip loins were collected and fabricated into 4 roasts and aged for 3, 14, 21, or 35 d postmortem. Fiber type was determined by immunohistochemistry. After aging, objective tenderness and collagen solubility were measured. There was a treatment x day of aging (DOA) interaction for Warner-Bratzler shear force (WBSF; P 0.31). Soluble collagen amount tended to be affected (P = 0.06) by a treatment x DOA interaction which was due to COMBO muscle having more soluble collagen than the other 2 treatments on d 21 of aging (P < 0.02). Correlation analysis indicated that type I, IIA, and IIX fiber CSA are positively correlated with WBSF at d 3 and 14 of aging (P < 0.01), but only type IIX fibers are correlated at d 21 and 35 of aging (P < 0.03). At these time periods, total and insoluble collagen became positively correlated with WBSF (P < 0.01). This would indicate that relationship between muscle fiber CSA and WBSF decreases during postmortem aging, while the association between WBSF and collagen characteristics strengthens. The use of GP negatively impacted meat tenderness primarily through increased muscle fiber CSA and not through altering collagen solubility

    S17(0) Determined from the Coulomb Breakup of 83 MeV/nucleon 8B

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    A kinematically complete measurement was made of the Coulomb dissociation of 8B nuclei on a Pb target at 83 MeV/nucleon. The cross section was measured at low relative energies in order to infer the astrophysical S factor for the 7Be(p,gamma)8B reaction. A first-order perturbation theory analysis of the reaction dynamics including E1, E2, and M1 transitions was employed to extract the E1 strength relevant to neutrino-producing reactions in the solar interior. By fitting the measured cross section from Erel = 130 keV to 400 keV, we find S17(0) = 17.8 (+1.4, -1.2) eV b

    Characterization of Sleep Stages by Correlations of Heartbeat Increments

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    We study correlation properties of the magnitude and the sign of the increments in the time intervals between successive heartbeats during light sleep, deep sleep, and REM sleep using the detrended fluctuation analysis method. We find short-range anticorrelations in the sign time series, which are strong during deep sleep, weaker during light sleep and even weaker during REM sleep. In contrast, we find long-range positive correlations in the magnitude time series, which are strong during REM sleep and weaker during light sleep. We observe uncorrelated behavior for the magnitude during deep sleep. Since the magnitude series relates to the nonlinear properties of the original time series, while the signs series relates to the linear properties, our findings suggest that the nonlinear properties of the heartbeat dynamics are more pronounced during REM sleep. Thus, the sign and the magnitude series provide information which is useful in distinguishing between the sleep stages.Comment: 7 pages, 4 figures, revte
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