12,210 research outputs found

    Transonic wind-tunnel tests of an F-8 airplane model equipped with 12 and 14-percent thick oblique wings

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    An experimental investigation was conducted in the Ames 14-foot transonic wind tunnel to study the aerodynamic performance and stability characteristics of a 0.087-scale model of an F-8 airplane fitted with an oblique wing. Two elliptical planform (axis ratio = 8:1) wings, each having a maximum thickness of 12 and 14 percent, were tested. Longitudinal stability data were obtained with no wing and with each of the two wings set at sweep angles of 0, 45, and 60 deg. Lateral directional stability data were obtained for the 12 percent wing only. Test Mach numbers ranged from 0.6 to 1.2 in the unit Reynolds number range from 11.2 to 13.1 million per meter. Angles of attack were between -6 and 22 deg at zero sideslip. Angles of sideslip were between -6 and +6 deg for two angles of attack, depending upon the wing configuration

    Nonlocal hydrodynamic influence on the dynamic contact angle: Slip models versus experiment

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    Experiments reported by Blake et al. [Phys. Fluids. 11, 1995 (1999)] suggest that the dynamic contact angle formed between the free surface of a liquid and a moving solid boundary at a fixed contact-line speed depends on the flow field/geometry near the moving contact line. The present paper examines quantitatively whether or not it is possible to attribute this effect to bending of the free surface due to hydrodynamic stresses acting upon it and hence interpret the results in terms of the so-called ``apparent'' contact angle. It is shown that this is not the case. Numerical analysis of the problem demonstrates that, at the spatial resolution reported in the experiments, the variations of the ``apparent'' contact angle (defined in two different ways) caused by variations in the flow field, at a fixed contact-line speed, are too small to account for the observed effect. The results clearly indicate that the actual (macroscopic) dynamic contact angle, i.e.\ the one used in fluid mechanics as a boundary condition for the equation determining the free surface shape, must be regarded as dependent not only on the contact-line speed but also on the flow field/geometry in the vicinity of the moving contact line

    Fronto-striatal cognitive deficits at different stages of Parkinson's disease

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    Groups of patients with idiopathic Parkinson's disease, either medicated or unmedicated, were compared with matched groups of normal controls on a computerized battery previously shown to be sensitive to frontal lobe dysfunction, including tests of planning, spatial working memory and attentional set-shifting. In a series of problems based on the 'Tower of London' test, medicated patients with Parkinson's disease were shown to be impaired in the amount of time spent thinking about (planning) the solution to each problem. Additionally, an impairment in terms of the accuracy of the solution produced on this test was only evident in those patients with more severe clinical symptoms and was accompanied by deficits in an associated test of spatial short-term memory. Medicated patients with both mild and severe clinical symptoms were also impaired on a related test of spatial working memory. In contrast, a group of patients who were unmedicated and 'early in the course' of the disease were unimpaired in all three of these tests. However, all three Parkinson's disease groups were impaired in the test of attentional set-shifting ability, although unimpaired in a test of pattern recognition which is insensitive to frontal lobe damage. These data are compared with those previously published from a group of young neurosurgical patients with localized excisions of the frontal lobes and are discussed in terms of the specific nature of the cognitive deficit at different stages of Parkinson's disease

    Transonic lateral and longitudinal control characteristics of an F-8 airplane model equipped with an oblique wing

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    The aerodynamic stability and control characteristics of a 0.087-scale model of an F-8 airplane fitted with an oblique wing was studied. The wing had an elliptical planform (axis ratio = 8:1), a maximum thickness of 12 percent, and was tested at three sweep angles, 0, 45, and 60 deg. Six-component force and moment data were measured at zero sideslip for angles of attack between -6 and +16 deg, with the left and right ailerons deflected one at a time at angles between -14 deg and +14. Further tests were made with the horizontal tail deflected -5 and +2.5 deg. Test Mach numbers ranged from 0.6 to 1.4 at a Reynolds number of 20 million/m

    Nurses\u27 Alumnae Association Bulletin, April 1961

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    Alumnae Meetings 1960 Social Committee Clara Melville Scholarship Fund Bulletin Committee Private Duty Nurse\u27s Section Report of the School of Nursing and Nursing Service Staff Nurses Association Student Activities Personal Items of Interest Expansion of Jefferson Artificial Kidney Unit Medical Work in the Congo Marriages New Arrivals Necrology Annual Giving Fun

    Nurses\u27 Alumnae Association Bulletin, April 1962

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    Staff Nurses Association Alumnae Meetings 1961 Social Committee Clara Melville Scholarship Fund Ways and Means Report Cook Book Report Bulletin Committee Private Duty Nurse\u27s Section Hospital Report and Nursing Service Federal Nursing Service Practice of Nursing Report of Student Council Activities Medical Work in Ghan

    A structural evaluation of the tungsten isotopes via thermal neutron capture

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    Total radiative thermal neutron-capture γ\gamma-ray cross sections for the 182,183,184,186^{182,183,184,186}W isotopes were measured using guided neutron beams from the Budapest Research Reactor to induce prompt and delayed γ\gamma rays from elemental and isotopically-enriched tungsten targets. These cross sections were determined from the sum of measured γ\gamma-ray cross sections feeding the ground state from low-lying levels below a cutoff energy, Ecrit_{\rm crit}, where the level scheme is completely known, and continuum γ\gamma rays from levels above Ecrit_{\rm crit}, calculated using the Monte Carlo statistical-decay code DICEBOX. The new cross sections determined in this work for the tungsten nuclides are: σ0(182W)=20.5(14)\sigma_{0}(^{182}{\rm W}) = 20.5(14) b and σ11/2+(183Wm,5.2s)=0.177(18)\sigma_{11/2^{+}}(^{183}{\rm W}^{m}, 5.2 {\rm s}) = 0.177(18) b; σ0(183W)=9.37(38)\sigma_{0}(^{183}{\rm W}) = 9.37(38) b and σ5(184Wm,8.33μs)=0.0247(55)\sigma_{5^{-}}(^{184}{\rm W}^{m}, 8.33 \mu{\rm s}) = 0.0247(55) b; σ0(184W)=1.43(10)\sigma_{0}(^{184}{\rm W}) = 1.43(10) b and σ11/2+(185Wm,1.67min)=0.0062(16)\sigma_{11/2^{+}}(^{185}{\rm W}^{m}, 1.67 {\rm min}) = 0.0062(16) b; and, σ0(186W)=33.33(62)\sigma_{0}(^{186}{\rm W}) = 33.33(62) b and σ9/2+(187Wm,1.38μs)=0.400(16)\sigma_{9/2^{+}}(^{187}{\rm W}^{m}, 1.38 \mu{\rm s}) = 0.400(16) b. These results are consistent with earlier measurements in the literature. The 186^{186}W cross section was also independently confirmed from an activation measurement, following the decay of 187^{187}W, yielding values for σ0(186W)\sigma_{0}(^{186}{\rm W}) that are consistent with our prompt γ\gamma-ray measurement. The cross-section measurements were found to be insensitive to choice of level density or photon strength model, and only weakly dependent on Ecrit_{\rm crit}. Total radiative-capture widths calculated with DICEBOX showed much greater model dependence, however, the recommended values could be reproduced with selected model choices. The decay schemes for all tungsten isotopes were improved in these analyses.Comment: 25 pages, 15 figures, 15 table
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