666 research outputs found

    Low-speed wind-tunnel results for symmetrical NASA LS(1)-0013 airfoil

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    A wind-tunnel test has been conducted in the Langley Low-Turbulence Pressure Tunnel to evaluate the performance of a symmetrical NASA LS(1)-0013 airfoil which is a 13-percent-thick, low-speed airfoil. The airfoil contour was obtained from the thickness distribution of a 13-percent-thick, high-performance airfoil developed for general aviation airplanes. The tests were conducted at Mach numbers from 0.10 tp 0.37 over a Reynolds number range from about 0.6 to 12.0 X 10 to the 6th power. The angle of attack varied from about -8 to 20 degrees. The results indicate that the aerodynamic characteristics of the present airfoil are similar to, but slightly better than, those of the NACA 0012 airfoil

    Antiplane elastic wave propagation in pre-stressed periodic structures; tuning, band gap switching and invariance

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    The effect of nonlinear elastic pre-stress on antiplane elastic wave propagation in a two-dimensional periodic structure is investigated. The medium consists of cylindrical annuli embedded on a periodic square lattice in a uniform host material. An identical inhomogeneous deformation is imposed in each annulus and the theory of small-on-large is used to find the incremental wave equation governing subsequent small-amplitude antiplane waves. The plane-wave-expansion method is employed in order to determine the permissable eigenfrequencies. It is found that pre-stress significantly affects the band gap structure for Mooney–Rivlin and Fung type materials, allowing stop bands to be switched on and off. However, it is also shown that for a specific class of materials, their phononic properties remain invariant under nonlinear deformation, permitting some rather interesting behaviour and leading to the possibility of phononic cloaks

    Low-speed aerodynamic characteristics of a 16-percent-thick variable-geometry airfoil designed for general aviation applications

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    Tests were conducted in the Langley low-turbulence pressure tunnel to determine the aerodynamic characteristics of climb, cruise, and landing configurations. These tests were conducted over a Mach number range from 0.10 to 0.35, a chord Reynolds number range from 2.0 x 1 million to 20.0 x 1 million, and an angle-of-attack range from -8 deg to 20 deg. Results show that the maximum section lift coefficients increased in the Reynolds number range from 2.0 x 1 million to 9.0 x 1 million and reached values of approximately 2.1, 1.8, and 1.5 for the landing, climb, and cruise configurations, respectively. Stall characteristics, although of the trailing-edge type, were abrupt. The section lift-drag ratio of the climb configuration with fixed transition near the leading edge was about 78 at a lift coefficient of 0.9, a Mach number of 0.15, and a Reynolds number of 4.0 x 1 million. Design lift coefficients of 0.9 and 0.4 for the climb and cruise configurations were obtained at the same angle of attack, about 6 deg, as intended. Good agreement was obtained between experimental results and the predictions of a viscous, attached-flow theoretical method

    Charnel practices in medieval England: new perspectives

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    Studies of English medieval funerary practice have paid limited attention to the curation of human remains in charnel houses. Yet analysis of architectural, archaeological and documentary evidence, including antiquarian accounts, suggests that charnelling was more widespread in medieval England than has hitherto been appreciated, with many charnel houses dismantled at the sixteenth-century Reformation. The survival of a charnel house and its human remains at Rothwell, Northamptonshire permits a unique opportunity to analyse charnel practice at a medieval parish church. Employing architectural, geophysical and osteological analysis, we present a new contextualisation of medieval charnelling. We argue that the charnel house at Rothwell, a subterranean room constructed during the thirteenth century, may have been a particularly sophisticated example of an experiment born out of beliefs surrounding Purgatory. Our approach enables re-evaluation of the surviving evidence for charnel practice in England and enhances wider narratives of medieval charnelling across Europe

    Cognitive Information Processing

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    Contains reports on seven research projects.National Institutes of Health (Grant 5 P01 GM14940-03)National Institutes of Health (Grant 5 P01 GM15006-02)Joint Services Electronics Programs (U. S. Army, U.S. Navy, and U.S. Air Force) under Contract DA 28-043-AMC-02536(E)National Institutes of Health (Grant 5 TOl GM-01555-02

    Cognitive Information Processing

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    Contains reports on six research projects.National Institutes of Health (Grant 5 PO1 GM14940-04)National Institutes of Health (Grant 5 PO1 GM15006-03)Joint Services Electronics Programs (U. S. Army, U.S. Navy, and U.S. Air Force) under Contract DA 28-043-AMC-02536(E

    The circulatory effects produced in a patient with pneumopericardium by artificially varying the intrapericardial pressure

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    1. 1. Observations on changes in pulse rate, respiratory rate, arterial pressure, venous pressure, and circulation time were made with artificially produced changes in intrapericardial pressure in a patient with pneumopericardium. These relationships have been illustrated graphically.2. 2. The intrapericardial pressure fluctuated with respiration, and, as higher pressures were reached, these fluctuations decreased.3. 3. The intrapericardial pressure fluctuated with systole and diastole. Kymographic tracings were made of the fluctuations in intrapericardial pressure caused by respiration and the heartbeat. With the higher intrapericardial pressures, the changes in pressure produced by systole and diastole were less marked.4. 4. Significant changes in pulse rate, arterial pressure, venous pressure, and circulation time did not occur until the intrapericardial pressure was elevated to, or above, 145 mm. of water.5. 5. In order to maintain the circulation, it was necessary that venous pressure exceed intrapericardial pressure by at least 35 to 40 mm. of water.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32599/1/0000739.pd
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