3,878 research outputs found

    Simulation Assisted Risk Assessment: Blast Overpressure Modeling

    Get PDF
    A probabilistic risk assessment (PRA) approach has been developed and applied to the risk analysis of capsule abort during ascent. The PRA is used to assist in the identification of modeling and simulation applications that can significantly impact the understanding of crew risk during this potentially dangerous maneuver. The PRA approach is also being used to identify the appropriate level of fidelity for the modeling of those critical failure modes. The Apollo launch escape system (LES) was chosen as a test problem for application of this approach. Failure modes that have been modeled and/or simulated to date include explosive overpressure-based failure, explosive fragment-based failure, land landing failures (range limits exceeded either near launch or Mode III trajectories ending on the African continent), capsule-booster re-contact during separation, and failure due to plume-induced instability. These failure modes have been investigated using analysis tools in a variety of technical disciplines at various levels of fidelity. The current paper focuses on the development and application of a blast overpressure model for the prediction of structural failure due to overpressure, including the application of high-fidelity analysis to predict near-field and headwinds effects

    Use of Standardized Patient Scenarios to Train Medical Assistants in an Ambulatory Rehabilitation Medicine Clinic

    Get PDF
    Objectives: To improve the efficiency of our outpatient Rehabilitation Medicine clinic without sacrificing high value/quality patient care. To clarify the responsibilities of the MA and identify areas of redundancy in the rooming process. To demonstrate the utility of in-situ simulation for MA training. To reduce the time it takes for MAs to complete all assigned tasks to 10 minutes or less per encounter in at least 50% of patient encounters within two months from the time of intervention. To potentially highlight other areas in which to improve clinic efficiency and overall patient satisfaction (e.g. front desk registration process, resident and attending physician encounters, clinic and exam room accessibility).https://jdc.jefferson.edu/patientsafetyposters/1051/thumbnail.jp

    Simulation of Blast Waves with Headwind

    Get PDF
    The blast wave resulting from an explosion was simulated to provide guidance for models estimating risks for human spacecraft flight. Simulations included effects of headwind on blast propagation, Blasts were modelled as an initial value problem with a uniform high energy sphere expanding into an ambient field. Both still air and cases with headwind were calculated

    Adult Education and the Arts: A Marriage of Mind, Body, Heart and Soul

    Get PDF
    The authors of an upcoming publication on artistic ways of knowing share their findings through poetic expression

    Mounting and Alignment of IXO Mirror Segments

    Get PDF
    A suspension-mounting scheme is developed for the IXO (International X-ray Observatory) mirror segments in which the figure of the mirror segment is preserved in each stage of mounting. The mirror, first fixed on a thermally compatible strongback, is subsequently transported, aligned and transferred onto its mirror housing. In this paper, we shall outline the requirement, approaches, and recent progress of the suspension mount processes

    Recent Decline in Extratropical Lower Stratospheric Ozone Attributed to Circulation Changes

    Get PDF
    1998-2016 ozone trends in the lower stratosphere (LS) are examined using the Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2) and related NASA products. After removing biases resulting from step-changes in the MERRA-2 ozone observations, a discernible negative trend of -1.67+/-0.54 Dobson units per decade (DU/decade) is found in the 10-km layer above the tropopause between 20 deg N and 60 deg N. A weaker but statistically significant trend of -1.17+/-0.33 DU/decade exists between 50 deg S and 20 deg S. In the Tropics, a positive trend is seen in a 5-km layer above the tropopause. Analysis of an idealized tracer in a model simulation constrained by MERRA-2 meteorological fields provides strong evidence that these trends are driven by enhanced isentropic transport between the tropical (20 deg S20 deg N) and extratropical LS in the past two decades. This is the first time that a reanalysis dataset has been used to detect and attribute trends in lower stratospheric ozone. Plain Language Summary. Stratospheric ozone shields the biosphere from harmful ultraviolet radiation and affects the Earths radiative budget. Observational data show evidence that concentrations of ozone in the upper stratosphere have increased in the last 15 years. This is an expected result of the implementation of the Montreal Protocol and its amendments banning emissions of ozone depleting substances into the atmosphere. The evolution of stratospheric ozone is also impacted by climate change through its dependence on temperature and circulation, which can be different at different altitudes. These effects are less well understood. This study uses NASAs data and computer models to analyze the long-term changes in ozone since 1998. It is shown that the increase in the upper stratospheric ozone has been partially offset by a small but discernible decline of ozone concentrations in the lowermost stratosphere, in qualitative agreement with one recent study. A chemistry model simulation forced by meteorological data provides strong evidence that the primary mechanism driving this negative trend is an intensification of transport of ozone-poor air from the tropics into the extratropics, indicative of a systematic change in the lower-stratospheric circulation between 1998 and 2016

    The influence of in-pregnancy smoking cessation programmes on partner quitting and women's social support mobilization: a randomized controlled trial [ISRCTN89131885]

    Get PDF
    BACKGROUND: Smoking cessation interventions in pregnancy could influence a woman's social behaviour and her partner's smoking behaviour, but this has not been examined in any published randomized trials. METHOD: 918 women smoking at booking for antenatal care were enrolled in a cluster-randomized trial of three interventions: standard care, self-help manual and enhanced stage-based counselling, or self-help manual, enhanced stage-based counselling and use of an interactive computer program. The outcomes were change in social support received by women between booking for maternity care and 30 weeks gestation and 10 days postpartum and reported cessation in the woman's partner at these times. RESULTS: Few pregnant women's partners stopped smoking (4.1% at 30 weeks of gestation and 5.8% at 10 days postpartum) and the probability of quitting did not differ significantly by trial arm. Women's scores on the Inventory of Socially Supportive Behaviors showed a slight decline from booking to 30 weeks gestation, and a slight increase to 10 days postpartum, but these changes did not differ significantly by trial arm. CONCLUSION: The stage-based interventions tested in this trial aimed partly to influence women's mobilization of support and might have influenced partners' quitting, but there was no evidence that they did so. Given that women and their partners often stopped smoking together, future interventions to prevent smoking in pregnant women could encourage both partners to quit together
    • …
    corecore