30,387 research outputs found

    Planetary investigation utilizing an imaging spectrometer system based upon charge injection technology

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    An intrinsic silicon charge injection device (CID) television sensor array has been used in conjunction with a CaMoO4 colinear tunable acousto optic filter, a 61 inch reflector, a sophisticated computer system, and a digital color TV scan converter/computer to produce near IR images of Saturn and Jupiter with 10A spectral resolution and approximately 3 inch spatial resolution. The CID camera has successfully obtained digitized 100 x 100 array images with 5 minutes of exposure time, and slow-scanned readout to a computer. Details of the equipment setup, innovations, problems, experience, data and final equipment performance limits are given

    Structural Tailoring of Advanced Turboprops (STAT) programmer's manual

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    The Structural Tailoring of Advanced Turboprops (STAT) computer program was developed to perform numerical optimizations on highly swept propfan blades. This manual describes the functionality of the STAT system from a programmer's viewpoint. It provides a top-down description of module intent and interaction. The purpose of this manual is to familiarize the programmer with the STAT system should he/she wish to enhance or verify the program's function

    Dissociation dynamics of fluorinated ethene cations:\ud from time bombs on a molecular level to double-regime dissociators\ud

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    The dissociative photoionization mechanism of internal energy selected C2_2H3_3F+^+, 1,1-C2_2H2_2F2+_2^+, C2_2HF3+_3^+ and C2_2F4+_4^+ cations have been studied in the 13−20 eV photon energy range using imaging photoelectron photoion coincidence spectroscopy. Five predominant channels have been found; HF loss, statistical and non-statistical F loss, cleavage of the C–C bond post H or F-atom migration, and cleavage of the C=C bond. By modelling the breakdown diagrams and ion time-of-flight distributions using statistical theory, experimental 0 K appearance energies, E0_0, of the daughter ions have been determined. Both C2_2H3_3F+^+ and 1,1-C2_2H2_2F2+_2^+ are veritable time bombs with respect to dissociation via HF loss, where slow dissociation over a reverse barrier is followed by an explosion with large kinetic energy release. The first dissociative ionization pathway for C2_2HF3_3 and C2_2F4_4 involves an atom migration across the C=C bond, giving CF–CHF2+_2^+ and CF–CF3+_3^+, respectively, which then dissociate to form CHF2+_2^+ and CF3+_3^+. The nature of the F-loss pathway has been found to be bimodal for C2_2H3_3F and 1,1-C2_2H2_2F2_2, switching from statistical to non-statistical behaviour as the photon energy increases. The dissociative ionization of C2_2F4_4 is found to be comprised of two regimes. At high internal energies, a long-lived excited electronic state is formed, which loses an F atom in a non-statistical process and undergoes statistical redistribution of energy among the nuclear degrees of freedom. This is followed by a subsequent dissociation. In other words only the ground electronic state phase space stays inaccessible. The accurate E0_0 of CF3+_3^+ and CF+^+ formation from C2_2F4_4 together with the now well established ∆f_fHº of C2_2F4_4 yield self-consistent enthalpies of formation for the CF3_3, CF, CF3+_3^+, and CF+^+ species

    Study to establish cost predictions for the production of Redox chemicals

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    The chromium and iron chloride chemicals are significant first costs for NASA Redox energy storage systems. This study was performed to determine the lowest cost at which chromium and iron chlorides could be obtained for a complex of redox energy storage systems. In addition, since the solutions gradually become intermixed during the course of operation of Redox units, it was an objective to evaluate schemes for regeneration of the operating solutions. Three processes were evaluated for the production of chromium and iron chlorides. As a basis for the preliminary plant design and economic evaluation, it was assumed that the plant would produce about 25,000 tons of contained chromium as CrCl3 and an equivalent molar quantity of FeCl2. Preliminary plant designs, including materials and energy balances and sizing of major equipment, were prepared, and capital and operating costs were estimated

    Supersymmetric black rings and three-charge supertubes

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    We present supergravity solutions for 1/8-supersymmetric black supertubes with three charges and three dipoles. Their reduction to five dimensions yields supersymmetric black rings with regular horizons and two independent angular momenta. The general solution contains seven independent parameters and provides the first example of non-uniqueness of supersymmetric black holes. In ten dimensions, the solutions can be realized as D1-D5-P black supertubes. We also present a worldvolume construction of a supertube that exhibits three dipoles explicitly. This description allows an arbitrary cross-section but captures only one of the angular momenta.Comment: 59 pages, 6 figures; v2: minor correction

    Final evaluation of the saving gateway 2 pilot: main report

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    The Saving Gateway is a government initiative aimed at encouraging savings behaviour among people who do not usually save. Each pound placed into a Saving Gateway account is matched by the government at a certain rate and up to a monthly contribution limit. Matching provides a transparent and understandable incentive for eligible individuals to place funds in an account

    Design-for-test structure to facilitate test vector application with low performance loss in non-test mode.

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    A switching based circuit is described which allows application of voltage test vectors to internal nodes of a chip without the problem of backdriving. The new circuit has low impact on the performance of an analogue circuit in terms of loss of bandwidth and allows simple application of analogue test voltages into internal nodes. The circuit described facilitates implementation of the forthcoming IEEE 1149.4 DfT philosophy [1]

    Noncommutative Solitons and Intersecting D-Branes

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    We construct intersecting D-branes as noncommutative solitons in bosonic and type II string theory. ``Defect'' branes which are D-branes containing bubbles of the closed string vacuum play an important role in the construction.Comment: 17 pages, harvmac; published version with added clarification
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