212,711 research outputs found
Energy management system for glider type vehicle Patent
Data processing and display system for terminal guidance of X-15 aircraf
Low-speed wind tunnel investigation of an advanced supersonic cruise arrow-wing configuration
A preliminary assessment of possible means for improving the low speed aerodynamic characteristics of advanced supersonic cruise arrow wing configurations and to extend the existing data base of such configurations has been made. Principle configuration variables included wing-leading and trailing-edge flap deflection, fuselage nose strakes, and engine exhaust nozzle deflection. Results showed that deflecting the wing leading edge apex flaps downward provided improved longitudinal stability but resulted in reduced directional stability. The model exhibited relatively low values of directional stability over the operational angle of attack range and experienced large asymmetric yawing moments at high angles of attack. The use of nose strakes was found to be effective in increasing the directional stability and eliminating the asymmetric yawing moment
Wolf-Rayets in IC10: Probing the Nearest Starburst
IC10 is the nearest starburst galaxy, as revealed both by its Halpha surface
brightness and the large number of Wolf-Rayet stars (WRs) per unit area. The
relative number of known WC- to WN-type WRs has been thought to be unusually
high (~2), unexpected for IC10's metallicity. In this Letter we report the
first results of a new and deeper survey for WRs in IC10. We sucessfully
detected all of the spectroscopically known WRs, and based upon comparisons
with a neighboring control field, estimate that the total number of WRs in IC10
is about 100. We present spectroscopic confirmation of two of our WR
candidates, both of which are of WN type. Our photometric survey predicts that
the actual WC/WN ratio is ~0.3. This makes the WC/WN ratio of IC 10 consistent
with that expected for its metallicity, but greatly increases the already
unusually high number of WRs, resulting in a surface density that is about 20
times higher than in the LMC. If the majority of these candidates are
spectroscopically confirmed, IC10 must have an exceptional population of high
mass stars.Comment: Accepted by ApJL; only minor correction in this versio
High-power ac/dc variable load simulator
Design of medium-power dynamic electrical load simulator has been extended to permit simulation of ac as well as dc loads and to provide for operation at higher power levels. Simulator is internally protected against reverse voltage, overvoltage, overcurrent, and overload conditions
What if the UK had Joined the Euro in 1999? An Empirical Evaluation Using a Global VAR
This paper attempts to provide a conceptual framework for the analysis of counterfactual scenarios using macroeconometric models. As an application we consider UK entry to the euro. Entry involves a long-term commitment to restrict UK nominal exchange rates and interest rates to be the same as those of the euro area. We derive conditional probability distributions for the difference between the future realisations of variables of interest (e.g UK and euro area output and prices) subject to UK entry restrictions being fully met over a given period and the alternative realisations without the restrictions. The robustness of the results can be evaluated by also conditioning on variables deemed to be invariant to UK entry, such as oil or US equity prices. Economic interdependence means that such policy evaluation must take account of international linkages and common factors that drive fluctuations across economies. In this paper this is accomplished using the Global VAR recently developed by Dees, di Mauro, Pesaran and Smith (2005). The paper briefly describes the GVAR which has been estimated for 25 countries and the euro area over the period 1979-2003. It reports probability estimates that output will be higher and prices lower in the UK and the euro area as a result of entry. It examines the sensitivity of these results to a variety of assumptions about when and how the UK entered and the observed global shocks and compares them with the effects of Swedish entry.Global VAR (GVAR), counterfactual analysis, UK and Sweden entry to Euro
Fictitious Level Dynamics: A Novel Approach to Spectral Statistics in Disordered Conductors
We establish a new approach to calculating spectral statistics in disordered
conductors, by considering how energy levels move in response to changes in the
impurity potential. We use this fictitious dynamics to calculate the spectral
form factor in two ways. First, describing the dynamics using a Fokker-Planck
equation, we make a physically motivated decoupling, obtaining the spectral
correlations in terms of the quantum return probability. Second, from an
identity which we derive between two- and three-particle correlation functions,
we make a mathematically controlled decoupling to obtain the same result. We
also calculate weak localization corrections to this result, and show for two
dimensional systems (which are of most interest) that corrections vanish to
three-loop order.Comment: 35 pages in REVTeX format including 10 postscript figures; to be
published in a special issue (on Topics in Mesoscopic Physics) of the Journal
of Mathematical Physics, October 199
WISP information display system user's manual
The wind shears program (WISP) supports the collection of data on magnetic tape for permanent storage or analysis. The document structure provides: (1) the hardware and software configuration required to execute the WISP system and start up procedure from a power down condition; (2) data collection task, calculations performed on the incoming data, and a description of the magnetic tape format; (3) the data display task and examples of displays obtained from execution of the real time simulation program; and (4) the raw data dump task and examples of operator actions required to obtained the desired format. The procedures outlines herein will allow continuous data collection at the expense of real time visual displays
The Basic Psychological Needs in Exercise Scale: Translation and Evidence for Cross-Cultural Validity
The present study reports on the psychometric evaluation and cross-cultural validity of the Basic Psychological Needs in Exercise Scale (BPNES; Vlachopoulos & Michailidou, 2006) translated from Greek into English. The data obtained from 346 British exercise participants supported the hypothesized 3-factor structure,showed satisfactory internal reliability coefficients, and offered evidence for the factor concurrent, discriminant, and nomological validity of the translated scale.Cross-cultural validity analyses across British and Greek participants supported configural invariance and partial metric, partial strong, and partial strict factorial invariance of the BPNES responses. The findings provide promising evidence for the validity and reliability of the translated BPNES and support the use of the scale in single-culture and cross-culture exercise-related motivational research within the self-determination theory framework
A simulator study for the development and evaluation of operating procedures on a supersonic cruise research transport to minimize airport-community noise
Piloted-simulator studies were conducted to determine takeoff and landing operating procedures for a supersonic cruise research transport concept that result in predicted noise levels which meet current Federal Aviation Administration (FAA) certification standards. With the use of standard FAA noise certification test procedures, the subject simulated aircraft did not meet the FAA traded-noise-level standards during takeoff and landing. However, with the use of advanced procedures, this aircraft meets the traded-noise-level standards for flight crews with average skills. The advanced takeoff procedures developed involved violating some of the current Federal Aviation Regulations (FAR), but it was not necessary to violate any FAR noise-test conditions during landing approach. Noise contours were also determined for some of the simulated takeoffs and landings in order to indicate the noise-reduction advantages of using operational procedures other than standard
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