3,229 research outputs found
Effect of Local Magnetic Moments on the Metallic Behavior in Two Dimensions
The temperature dependence of conductivity in the metallic phase
of a two-dimensional electron system in silicon has been studied for different
concentrations of local magnetic moments. The local moments have been induced
by disorder, and their number was varied using substrate bias. The data suggest
that in the limit of the metallic behavior, as characterized by
, is suppressed by an arbitrarily small amount of scattering by
local magnetic moments.Comment: 4 pages, revtex, plus four encapsulated postscript figure
Bequeathed Loan to Zion Baptist Church by S. S. Mauney - 1928, February 4
Church records bequeathing a loan of $500 from the will of Mrs. Rachel Weathers to Zion Baptist Church by S. S. Mauney on February 4, 1928.https://digitalcommons.gardner-webb.edu/fay-webb-gardner-zion-baptist-church/1000/thumbnail.jp
Boeing 747 aircraft with large external pod for transporting outsize cargo
The effect on structural arrangement, system weight, and range performance of the cargo pod payload carrying capability was determined to include either the bridge launcher or a spacelab module on a Boeing 747 aircraft. Modifications to the carrier aircraft and the installation time required to attach the external pod to the 747 were minimized. Results indicate that the increase in pod size was minimal, and that the basic 747 structure was adequate to safely absorb the load induced by ground or air operation while transporting either payload
A study of high-altitude manned research aircraft employing strut-braced wings of high-aspect-ratio
The effect of increased wing aspect ratio of subsonic aircraft on configurations with and without strut bracing. Results indicate that an optimum cantilever configuration, with a wing aspect ratio of approximately 26, has a 19% improvement in cruise range when compared to a baseline concept with a wing aspect ratio of approximately 10. An optimum strut braced configuration, with a wing aspect ratio of approximately 28, has a 31% improvment in cruise range when compared to the same baseline concept. This improvement is mainly due to the estimated reduction in wing weight resulting from use of lifting struts. All configurations assume the same mission payload and fuel. The drag characteristics of the wings are enhanced with the use of laminar flow airfoils. A method for determining the extent of attainable natural laminar flow, and methods for preliminary structural design and for aerodynamic analysis of wings lifting struts are presented
Preliminary design characteristics of a subsonic business jet concept employing laminar flow control
Aircraft configurations were developed with laminar flow control (LFC) and without LFC. The LFC configuration had approximately eleven percent less parasite drag and a seven percent increase in the maximum lift-to drag ratio. Although these aerodynamic advantages were partially offset by the additional weight of the LFC system, the LFC aircraft burned from six to eight percent less fuel for comparable missions. For the trans-atlantic design mission with the gross weight fixed, the LFC configuration would carry a greater payload for ten percent fuel per passenger mile
Design of a large span-distributed load flying-wing cargo airplane with laminar flow control
A design study was conducted to add laminar flow control to a previously design span-distributed load airplane while maintaining constant range and payload. With laminar flow control applied to 100 percent of the wing and vertical tail chords, the empty weight increased by 4.2 percent, the drag decreased by 27.4 percent, the required engine thrust decreased by 14.8 percent, and the fuel consumption decreased by 21.8 percent. When laminar flow control was applied to a lesser extent of the chord (approximately 80 percent), the empty weight increased by 3.4 percent, the drag decreased by 20.0 percent, the required engine thrust decreased by 13.0 percent, and the fuel consumption decreased by 16.2 percent. In both cases the required take-off gross weight of the aircraft was less than the original turbulent aircraft
Preliminary design characteristics of a subsonic business jet concept employing an aspect ratio 25 strut braced wing
The advantages of replacing the conventional wing on a transatlantic business jet with a larger, strut braced wing of aspect ratio 25 were evaluated. The lifting struts reduce both the induced drag and structural weight of the heavier, high aspect ratio wing. Compared to the conventional airplane, the strut braced wing design offers significantly higher lift to drag ratios achieved at higher lift coefficients and, consequently, a combination of lower speeds and higher altitudes. The strut braced wing airplane provides fuel savings with an attendant increase in construction costs
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