2,414 research outputs found

    Minimum induced drag airfoil body Patent

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    Electric analog for measuring induced drag on nonplanar airfoil

    Process for control of cell division

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    A method of controlling mitosis of biological cells was developed, which involved inducing a change in the intracellular ionic hierarchy accompanying the cellular electrical transmembrane potential difference (Esubm) of the cells. The ionic hierarchy may be varied by imposing changes on the relative concentrations of Na(+), K(+) and Cl(-), or by directly imposing changes in the physical Esubm level across the cell surface

    Minimum induced drag airfoil body Patent

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    Electric analog for measuring induced drag on nonplanar airfoil

    Effect of Conflict Resolution Maneuver Execution Delay on Losses of Separation

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    This paper examines uncertainty in the maneuver execution delay for data linked conflict resolution maneuvers. This uncertainty could cause the previously cleared primary conflict to reoccur or a secondary conflict to appear. Results show that the likelihood of a primary conflict reoccurring during a horizontal conflict resolution maneuver increases with larger initial turn-out angles and with shorter times until loss of separation. There is also a significant increase in the probability of a primary conflict reoccurring when the time until loss falls under three minutes. Increasing horizontal separation by an additional 1.5 nmi lowers the risk, but does not completely eliminate it. Secondary conflicts were shown to have a small probability of occurring in all tested configurations

    Using publication metrics to highlight academic productivity and research impact

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    This article provides a broad overview of widely available measures of academic productivity and impact using publication data and highlights uses of these metrics for various purposes. Metrics based on publication data include measures such as number of publications, number of citations, the journal impact factor score, and the h-index, as well as emerging metrics based on document-level metrics. Publication metrics can be used for a variety of purposes for tenure and promotion, grant applications and renewal reports, benchmarking, recruiting efforts, and administrative purposes for departmental or university performance reports. The authors also highlight practical applications of measuring and reporting academic productivity and impact to emphasize and promote individual investigators, grant applications, or department output

    Failure Investigation of an Intra-Manifold Explosion in a Horizontally-Mounted 870 lbf Reaction Control Thruster

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    In June 2010, an 870 lbf Space Shuttle Orbiter Reaction Control System Primary Thruster experienced an unintended shutdown during a test being performed at the NASA White Sands Test Facility. Subsequent removal and inspection of the thruster revealed permanent deformation and misalignment of the thruster valve mounting plate. Destructive evaluation determined that after three nominal firing sequences, the thruster had experienced an energetic event within the fuel (monomethylhydrazine) manifold at the start of the fourth firing sequence. The current understanding of the phenomenon of intra-manifold explosions in hypergolic bipropellant thrusters is documented in literature where it is colloquially referred to as a ZOT. The typical ZOT scenario involves operation of a thruster in a gravitational field with environmental pressures above the triple point pressure of the propellants. Post-firing, when the thruster valves are commanded closed, there remains a residual quantity of propellant in both the fuel and oxidizer (nitrogen tetroxide) injector manifolds known as the "dribble volume". In an ambient ground test configuration, these propellant volumes will drain from the injector manifolds but are impeded by the local atmospheric pressure. The evacuation of propellants from the thruster injector manifolds relies on the fluids vapor pressure to expel the liquid. The higher vapor pressure oxidizer will evacuate from the manifold before the lower vapor pressure fuel. The localized cooling resulting from the oxidizer boiling during manifold draining can result in fuel vapor migration and condensation in the oxidizer passage. The liquid fuel will then react with the oxidizer that enters the manifold during the next firing and may produce a localized high pressure reaction or explosion within the confines of the oxidizer injector manifold. The typical ZOT scenario was considered during this failure investigation, but was ultimately ruled out as a cause of the explosion. Converse to the typical ZOT failure mechanism, the failure of this particular thruster was determined to be the result of liquid oxidizer being present within the fuel manifold

    The Effectiveness of a Group Intervention to Improve Coping Skills for Emotion Regulation in Preadolescent and Adolescent Males with Attachment Difficulties

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    This study was designed to assess the effectiveness of a six session cognitive-behavioral group intervention to improve coping skills for emotional regulation in male preadolescents and adolescents with attachment difficulties. There is a lack of research in the area of group interventions with male adolescents as well as interventions for adolescents with attachment difficulties. A multiple probe across groups and a multiple baseline across groups design were used in this study. The measures assessed difficulties in emotion regulation, coping strategies, adolescent adjustment, anger control, negative behaviors, and level of distress. Although there were no substantial findings and no hypotheses were supported, the current study did find that the participants enjoyed the group interaction and some wished to continue the group.M.A

    Pump Energy Conservation Techniques

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    LectureThousands of dollars are wasted annually in a typical petrochemical plant through inefficient operation of pumps. Excess capacity, changing operating conditions, inefficient control, and inadequate maintenance are some of the more common sources of wasted energy. In many cases, significant energy savings can be made by systematically applying existing technology to reduce pump energy consumption. This paper reviews available pump energy saving methods and presents application guidelines for both new pumping designs and retrofit into existing installations. Detailed examples are given for each of the twenty pump energy savings techniques that are discussed

    Controlled Compositional Disorder in Er3+:Y2SiO5 Provides a Wide-Bandwidth Spectral Hole Burning Material at 1.5mum

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    The subgigahertz spectral bandwidth of the lowest energy 1.5mum Er3+ I15/24--\u3eI13/24 optical transition in Er3+:Y2SiO5 has been increased to ˜22GHz by intentionally introducing compositional disorder through codoping with Eu3+ impurity ions. This illustrates a general bandwidth control technique for spectral hole burning device applications including spatial-spectral holography and quantum computing. Coherence measurements by stimulated photon echoes demonstrated that the increased disorder does not perturb the dynamical properties of the Er3+ transition and, thus, gives the desired bandwidth enhancement without penalty in other properties. The echo measurements and model analysis also show that phonon-driven spin flips of Er3+ ions in the ground state are responsible for the spectral diffusion that was observed for the optical transition. These results collectively give a better understanding of both the nature of disorder and of the ion-ion interactions in doped materials, and they also enable the high bandwidths required for signal processing and memory applications at 1.5mum based on spectral hole burning
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