4,834 research outputs found

    Calibration of a gamma-ray telescope using tagged position annihilation photons

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    Measurements of detection efficiency, angular resolution, and energy resolution properties of a gamma ray telescope used to study celestial gamma rays from balloon flight altitudes are described. Nearly monochromatic photons produced at the National Bureau of Standards tagged photon facility were used for the calibration. Details of the photon beam configuration and properties and results of the measurements made at photon energies of 15.1 and 31.1 MeV are presented. Finally, the data are compared with a Monte Carlo analysis of the instrument properties

    Simulated low-gravity sloshing in spherical tanks and cylindrical tanks with inverted ellipsoidal bottoms

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    Simulated low gravity sloshing in spherical and cylindrical tanks with inverted ellipsoidal bottom

    Low-gravity sloshing in rectangular tanks

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    Low-gravity sloshing in rectangular tank

    Propellant dynamics in an aircraft-type launch vehicle

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    Liquid propellant sloshing in tilted axisymmetric cylindrical tanks for space shuttle application

    Equivalent mechanical model of propellant sloshing in the workshop configuration of the Saturn S-4B Final report

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    Mechanical model for propellant sloshing in irregular compartmentation of S-4B Workshop configuration during roll and lateral excitation

    Experimental and theoretical studies of liquid sloshing at simulated low gravities

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    Low gravity liquid sloshing in rigid cylindrical tan

    Development of carbon slurry fuels for transportation (hybrid fuels, phase 2)

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    Slurry fuels of various forms of solids in diesel fuel are developed and evaluated for their relative potential as fuel for diesel engines. Thirteen test fuels with different solids concentrations are formulated using eight different materials. A variety of properties are examined including ash content, sulfur content, particle size distribution, and rheological properties. Attempts are made to determine the effects of these variations on these fuel properties on injection, atomization, and combustion processes. The slurries are also tested in a single cylinder CLR engine in both direct injection and prechamber configurations. The data includes the normal performance parameters as well as heat release rates and emissions. The slurries perform very much like the baseline fuel. The combustion data indicate that a large fraction (90 percent or more) of the solids are burning in the engine. It appears that the prechamber engine configuration is more tolerant of the slurries than the direct injection configuration

    Frailty is independently associated with increased hospitalisation days in patients on the liver transplant waitlist

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    AIM: To investigate the impact of physical frailty on risk of hospitalisation in cirrhotic patients on the liver transplant waitlist. METHODS: Cirrhotics listed for liver transplantation at a single centre underwent frailty assessments using the Fried Frailty Index, consisting of grip strength, gait speed, exhaustion, weight loss, and physical activity. Clinical and biochemical data including MELD score as collected at the time of assessment. The primary outcome was number of hospitalised days per year; secondary outcomes included incidence of infection. Univariable and multivariable analysis was performed using negative binomial regression to associate baseline parameters including frailty with clinical outcomes and estimated incidence rate ratios (IRR). RESULTS: Of 587 cirrhotics, 64% were male, median age (interquartile range) was 60 (53-64) years and MELD score was 15 (12-18). Median Fried Frailty Index was 2 (1-3); 31.6% were classified as frail (fried frailty ≥ 3). During 12 mo of follow-up, 43% required at least 1 hospitalisation; 38% of which involved major infection. 107/184 (58%) frail and 142/399 (36%) non-frail patients were hospitalised at least once (P < 0.001). In univariable analysis, Fried Frailty Index was associated with total hospitalisation days per year (IRR = 1.51, 95%CI: 1.28-1.77; P ≤ 0.001), which remained significant on multivariable analysis after adjustment for MELD, albumin, and gender (IRR for frailty of 1.21, 95%CI: 1.02-1.44; P = 0.03). Incidence of infection was not influenced by frailty. CONCLUSION: In cirrhotics on the liver transplant waitlist, physical frailty is a significant predictor of hospitalisation and total hospitalised days per year, independent of liver disease severity
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