2,878 research outputs found

    Advanced general aviation comparative engine/airframe integration study

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    The NASA Advanced Aviation Comparative Engine/Airframe Integration Study was initiated to help determine which of four promising concepts for new general aviation engines for the 1990's should be considered for further research funding. The engine concepts included rotary, diesel, spark ignition, and turboprop powerplants; a conventional state-of-the-art piston engine was used as a baseline for the comparison. Computer simulations of the performance of single and twin engine pressurized aircraft designs were used to determine how the various characteristics of each engine interacted in the design process. Comparisons were made of how each engine performed relative to the others when integrated into an airframe and required to fly a transportation mission

    American Hypocrisy in Foreign Policy: Operation FUBELT and the Overthrow of Salvador Allende

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    There are many examples of United States hypocrisy in foreign policy, in numerous countries in virtually every region of the world. This paper will look at just one of those examples, the United States involvement in the overthrow of President Salvador Allende of Chile. Declassified government documents related to the CIA operation, codenamed FUBELT, are used to show key personnel involved and major aspects of the operation. These documents show a blatant disregard of the United States government\u27s own ideology and policies regarding democracy, as well as its disregard of the United Nations documents that it signed to guarantee the right of self determination. The disregard of these rights that the United States has agreed to under the United Nations charter and the rights to a free and democratic society as guaranteed by our own Constitution are the heart of the hypocrisy of United States foreign policy. This is just one of the many reasons that the United States has such a terrible image among many of the nations in Latin America. It is an image that is tarnished as a direct result of our own political hypocrisy, the Cold War, and the desire of every President since Harry Truman to keep the United States in the spotlight of the world stage as a superpower

    Filaments as Possible Signatures of Magnetic Field Structure in Planetary Nebulae

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    We draw attention to the extreme filamentary structures seen in high-resolution optical images of certain planetary nebulae. We determine the physical properties of the filaments in the nebulae IC 418, NGC 3132, and NGC 6537, and based on their large length-to-width ratios, longitudinal coherence, and morphology, we suggest that they may be signatures of the underlying magnetic field. The fields needed for the coherence of the filaments are probably consistent with those measured in the precursor circumstellar envelopes. The filaments suggest that magnetic fields in planetary nebulae may have a localized and thread-like geometry.Comment: 26 pages with 7 figures. To be published in PASP. For full resolution images see http://physics.nyu.edu/~pjh

    A model of large volumetric capacitance in graphene supercapacitors based on ion clustering

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    Electric double layer supercapacitors are promising devices for high-power energy storage based on the reversible absorption of ions into porous, conducting electrodes. Graphene is a particularly good candidate for the electrode material in supercapacitors due to its high conductivity and large surface area. In this paper we consider supercapacitor electrodes made from a stack of graphene sheets with randomly-inserted "spacer" molecules. We show that the large volumetric capacitances C > 100 F/cm^3 observed experimentally can be understood as a result of collective intercalation of ions into the graphene stack and the accompanying nonlinear screening by graphene electrons that renormalizes the charge of the ion clusters.Comment: 13 pages, 5 figures; additional discussion and supporting calculations adde

    The massive expanding molecular torus in the planetary nebula NGC 6302

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    We measure the mass and kinematics of the massive molecular torus in the planetary nebula NGC 6302. The nebula is the proto-typical butterfly nebula. The origin of the wing-like morphology is disputed: determining the mass-loss history of the confining torus is an important step in understanding the formation of this structure. We performed submillimeter observations with JCMT and the SMA interferometer. The continuum emission as well as the J=2-1 and 3-2 transitions of 12CO and 13CO are analysed at arcsecond resolution. The CO emission indicates a mass of the torus of ~ 2Msun +/- 1Msun. The 12CO and 13CO emission matches the dark lane seen in absorption in the Halpha image of the object. The CO torus is expanding with a velocity of ~ 8 km/s, centred at Vlsr=-31.5 km/s. The size and expansion velocity of the torus indicates that the torus was ejected from ~ 7500 yr to 2900 yr ago, with a mass-loss rate of 5x10^{-4}Msun/yr. We also see a ballistic component in the CO images with a velocity gradient of 140 km/s/pc. The derived mass-loss history of the torus favours binary interaction as the cause of the ejection of the torus. We predict the existence of a companion with an orbital period P < 1 month.Comment: 13 pages, 10 figures, accepted for publication in A&

    Mark-and-Recapture Methods for Studying Domestic Cockroach Populations

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    Mark and recapture methods were used to estimate populations of American cockroaches, Periplenata americana (Linnaeus), and brown-banded cockroaches, Supella supellectilium (Serville) inhabiting various rooms in the Science Hall, Iowa State University. These methods also permitted estimates of sex ratios, length-frequencies, movement, and activity patterns. Food appeared to be the limiting factor in determining size of cockroach populations. Males outnumbered females in both species with total sex ratios being.8 and.6 for brown-banded and American cockroaches, respectively. Most of the American cockroaches caught were over 28.0 mm. with the 36.1 - 40.0 mm. class being the largest. The brown-banded cockroach catch contained two large length classes, 2.5 - 4.0 mm. and 12.5 - 14.0 mm., suggesting two major age classes. Room-to-room movement of cockroaches was limited, and over 93 percent of the catch occurred during the dark hours

    Solid state television camera system Patent

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    Solid state television camera system consisting of monolithic semiconductor mosaic sensor and molecular digital readout system
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