11,538 research outputs found

    Evaluation of TILS for use as the orbiter landing NAVAID

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    An evaluation of the tactical instrument landing systems (TILS) for use in the orbiter autoland system was made. It was found that with certain modifications, the TILS can satisfy orbiter autoland requirements. These modifications, include (1) addition of DME equipment, (2) expansion of elevation coverage from 0-10 deg to 0-30 deg, and (3) expansion to redundant systems with associated ground monitors. Additional modifications that are not necessary to meet the orbiter requirements, but that can enhance performance margin are (1) tightening of elevation antenna beam width from 1.3 deg to 0.5 deg and (2) split site configuration to provide azimuth and range coverage through rollout

    Advanced flight deck/crew station simulator functional requirements

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    This report documents a study of flight deck/crew system research facility requirements for investigating issues involved with developing systems, and procedures for interfacing transport aircraft with air traffic control systems planned for 1985 to 2000. Crew system needs of NASA, the U.S. Air Force, and industry were investigated and reported. A matrix of these is included, as are recommended functional requirements and design criteria for simulation facilities in which to conduct this research. Methods of exploiting the commonality and similarity in facilities are identified, and plans for exploiting this in order to reduce implementation costs and allow efficient transfer of experiments from one facility to another are presented

    Defect physics of BaCuChF (Ch=S, Se, Te) p-type transparent conductors

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    Native point defects, defect complexes, and oxygen impurities in BaCuChF were studied using density functional theory calculations, self-consistent thermodynamic simulations, and various experimental techniques. Unintentional p-type conductivity in BaCuChF is explained by the presence of copper vacancies with transition levels in the valence band. These acceptor-like defects are partially compensated by donor-like chalcogen vacancies with transition levels deep in the gap. Chalcogen vacancies also cause the experimentally observed sub-gap photoluminescence, optical absorption, and persistent photoconductivity in BaCuSF and BaCuSeF. In thermodynamic equilibrium, both copper and chalcogen vacancies have low formation enthalpies and are likely to form defect complexes among themselves and with fluorine interstitials. The calculated Fermi level pinning range in BaCuChF is narrow and located close to the valence band maximum. It makes BaCuChF a suitable transparent p-type contact layer for optoelectronic applications, but hinders attempts to fabricate transparent thin film transistors using this material. Oxygen-related defects do not affect bulk BaCuChF properties, but surface oxidation decreases the mean free path of free holes by almost an order of magnitude.Comment: 28 pages, 5 figure

    Multi-Satellite Attitude Prediction program/Orbiting Solar Observatory-8 (MSAP/OSO-8) operating guide

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    The sun's lower corona and chromosphere and their interaction in the X-ray and ultraviolet (UV) spectral regions were investigated to better understand the transport of energy from the photosphere to the corona. The interaction between the solar electromagnetic and particle radiation and the earth's environment was studied and the background component of cosmic X-rays was discussed

    On the etale cohomology of algebraic varieties with totally degenerate reduction over p-adic fields

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    Let K be a finite extension of Q_p and X a smooth projective variety over K. We define the notion of totally degenerate reduction of such an X and the associated Chow complexes of the special fibre of a suitable regular proper model of X over the ring of integers of K. If X has such reduction, we then show that for all l, the Q_l-adic etale cohomology of X has a filtration whose graded quotients are isomorphic, as Galois modules, to the tensor product of a finite dimensional Q-vector space (with a finite unramified action of Galois) with twists of Q_l by the cyclotomic character.Comment: 29 pages This and math.AG/0601401 replace math.AG/030612

    Real-world comparison of probe vehicle emissions and fuel consumption using diesel and 5 % biodiesel (B5) blend.

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    An instrumented EURO I Ford Mondeo was used to perform a real-world comparison of vehicle exhaust (carbon dioxide, carbon monoxide, hydrocarbons and oxides of nitrogen) emissions and fuel consumption for diesel and 5% biodiesel in diesel blend (B5) fuels. Data were collected on multiple replicates of three standardised on-road journeys: (1) A simple urban route; (2) A combined urban/inter-urban route; and, (3) An urban route subject to significant traffic management. At the total journey measurement level, data collected here indicate that replacing diesel with a B5 substitute could result in significant increases in both NOx emissions (8-13%) and fuel consumption (7-8%). However, statistical analysis of probe vehicle data demonstrated the limitations of comparisons based on such total journey measurements, i.e., methods analogous to those used in conventional dynamometer/drive cycle fuel comparison studies. Here, methods based on the comparison of speed/acceleration emissions and fuel consumption maps are presented. Significant variations across the speed/acceleration surface indicated that direct emission and fuel consumption impacts were highly dependent on the journey/drive cycle employed. The emission and fuel consumption maps were used both as descriptive tools to characterise impacts and predictive tools to estimate journey-specific emission and fuel consumption effects

    In Service CO2 and NOX Emissions of Euro 6/VI Cars, Light- and Heavy- dutygoods Vehicles in Real London driving: Taking the Road into the Laboratory

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    Driving on-the-road has more frequent and prompt acceleration/decelerations than in the type-approval light-duty test conditions (NEDC), with Real Driving Emissions (RDE) of CO2 and NOX known to be considerably higher. Despite permissible limits of NOX emissions at type approval reducing significantly, in-service emissions from diesel vehicles have, in reality, not reduced at all through the Euro 1–5 / I–V emission standards. TfL commissioned a programme of laboratory testing to better understand the in-service emission performance of Euro 6/VI vehicles over the TfL London Drive Cycle (LDC). This cycle was constructed from instrumented car data making repeated circuits of a set route at different times of day. Twelve Euro 6 passenger cars were tested over the entire 140 kms of the LDC from a warm-start. Three HGVs were tested over the suburban sub-cycle (40kms) in laden and un-laden condition. NOX emissions from the petrol cars were at a low level and below, or at, their type approval limit of 0.06 g.km-1. Only one SCR equipped diesel car achieved NOX emissions close to their 0.08 g.km-1 type approval limit. NOX emissions from diesel cars with only LNT NOX controls were between 3 and 13 times higher than their type approval limit (conformity factors). A diesel supermini was emitting NOX at the same level as the fully laden 40T artic HGV tested
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