8,831 research outputs found

    Jet engine air intake system

    Get PDF
    An axisymmetric air intake system for a jet aircraft engine comprising a fixed cowl extending outwardly from the face of the engine, a centerbody coaxially disposed within the cowl, and an actuator for axially displacing the centerbody within the cowl was developed. The cowl and centerbody define a main airflow passageway therebetween, the configuration of which is changed by displacement of the centerbody. The centerbody includes a forwardly-located closeable air inlet which communicates with a centerbody auxiliary airflow passageway to provide auxiliary airflow to the engine. In one embodiment, a system for opening and closing the centerbody air inlet is provided by a dual-member centerbody, the forward member of which may be displaced axially with respect to the aft member

    Aircraft engine nozzle

    Get PDF
    A variable area exit nozzle arrangement for an aircraft engine was a substantially reduced length and weight which comprises a number of longitudinally movable radial vanes and a number of fixed radial vanes. The movable radial vanes are alternately disposed with respect to the fixed radial vanes. A means is provided for displacing the movable vanes along the longitudinal axis of the engine relative to the fixed radial vanes which extend across the main exhaust flow of the engine

    Paper Session II-C - Automated Military Space System Development and Technology Effectiveness

    Get PDF
    Not since the end of World War II has the United States military experienced such major changes. The changes are being driven by both internal national factors, and external international Cold War downsizing. The specifics of what the changes are and the explicit forcing factors have been understood for some time. What has not been understood thoroughly, is how the United States military will continue to maintain personnel and hardware effectiveness in such a dynamic environment, specifically amidst a steadily diversifying threat base and declining acquisition budget. Recently, there have been several efforts directly concerned with how the U.S. military space programs must change, i.e., provide more support to the military user with a declining space system acquisition budget. The two most significant efforts were a “Visions Study,” conducted by the Air Force Space and Missiles Center Planning Directorate in Los Angeles, and the “Re-Invent Space” supported by the joint services U.S. Space Command in Colorado Springs. Both studies assessed major paradigm shifts in all aspects of our current approach to conducting the military space business. Many of their findings and recommended areas of needed change are now being pushed forward for consideration by the newly formed Space Architecture office in Washington

    Paper Session II-C - Military Space: Global Change in the 21st Century

    Get PDF
    The observation of how rapidly the world is changing as a result of technological and economic pressure is to state the obvious. Predicting the present magnitude and rate of the change would have been impossible; projecting into the future will be an equally daunting task. Reflection upon the previous forty years of technological advancement is almost as hard to imagine as what the next forty years will bring in terms of technological products and capability. Yet, from an integrated business standpoint, it would be hard to envision a future with any major industrial business solely owned within any one national border or large economic consortiums which is not totally international

    Information transfer through a one-atom micromaser

    Full text link
    We consider a realistic model for the one-atom micromaser consisting of a cavity maintained in a steady state by the streaming of two-level Rydberg atoms passing one at a time through it. We show that it is possible to monitor the robust entanglement generated between two successive experimental atoms passing through the cavity by the control decoherence parameters. We calculate the entanglement of formation of the joint two-atom state as a function of the micromaser pump parameter. We find that this is in direct correspondence with the difference of the Shannon entropy of the cavity photons before and after the passage of the atoms for a reasonable range of dissipation parameters. It is thus possible to demonstrate information transfer between the cavity and the atoms through this set-up.Comment: Revtex, 5 pages, 2 encapsulated ps figures; added discussion on information transfer in relation with cavity photon statistics; typos corrected; Accepted for Publicaiton in Europhysics Letter

    Core excitation in Ozone localized to one of two symmetry-equivalent chemical bonds - molecular alignment through vibronic coupling

    Full text link
    Core excitation from terminal oxygen OT_T in O3_3 is shown to be an excitation from a localized core orbital to a localized valence orbital. The valence orbital is localized to one of the two equivalent chemical bonds. We experimentally demonstrate this with the Auger Doppler effect which is observable when O3_3 is core-excited to the highly dissociative OT_{T}1s1^{-1}7a11_1^1 state. Auger electrons emitted from the atomic oxygen fragment carry information about the molecular orientation relative to the electromagnetic field vector at the moment of excitation. The data together with analytical functions for the electron-peak profiles give clear evidence that the preferred molecular orientation for excitation only depends on the orientation of one bond, not on the total molecular orientation. The localization of the valence orbital "7a1_1" is caused by mixing of the valence orbital "5b2_2" through vibronic coupling of anti-symmetric stretching mode with b2_2-symmetry. To the best of our knowledge, it is the first discussion of the localization of a core excitation of O3_3. This result explains the success of the widely used assumption of localized core excitation in adsorbates and large molecules

    Jet multiplicities as the QGP thermometer

    Full text link
    It is proposed to use the energy behavior of mean multiplicities of jets propagating in a nuclear medium as the thermometer of this medium during the collision phases. The qualitative effects are demonstrated in the framework of the fixed coupling QCD with account of jet quenching.Comment: Modify version of hep-ph/0509344, 3 figure

    Fluctuation and flow probes of early-time correlations in relativistic heavy ion collisions

    Full text link
    Fluctuation and correlation observables are often measured using multi-particle correlation methods and therefore mutually probe the origins of genuine correlations present in multi-particle distribution functions. We investigate the common influence of correlations arising from the spatially inhomogeneous initial state on multiplicity and momentum fluctuations as well as flow fluctuations. Although these observables reflect different aspects of the initial state, taken together, they can constrain a correlation scale set at the earliest moments of the collision. We calculate both the correlation scale in an initial stage Glasma flux tube picture and the modification to these correlations from later stage hydrodynamic flow and find quantitative agreement with experimental measurements over a range of collision systems and energies.Comment: Proceedings of the 28th Winter Workshop on Nuclear Dynamics, Dorado del Mar, Puerto Rico, April 7-14, 201

    Evidence from Identified Particles for Active Quark and Gluon Degrees of Freedom

    Get PDF
    Measurements of intermediate pT (1.5 < pT < 5.0 GeV/c) identified particle distributions in heavy ion collisions at SPS and RHIC energies display striking dependencies on the number of constituent quarks in the corresponding hadron. One finds that elliptic flow at intermediate pT follows a constituent quark scaling law as predicted by models of hadron formation through coalescence. In addition, baryon production is also found to increase with event multiplicity much faster than meson production. The rate of increase is similar for all baryons, and seemingly independent of mass. This indicates that the number of constituent quarks determines the multiplicity dependence of identified hadron production at intermediate pT. We review these measurements and interpret the experimental findings.Comment: 8 pages, 5 figures, proceedings for SQM2006 conference in Los Angele

    Effect of acute copper sulfate exposure on olfactory responses to amino acids and pheromones in goldfish (Carassius auratus)

    Get PDF
    Exposure of olfactory epithelium to environmentally relevant concentrations of copper disrupts olfaction in fish. To examine the dynamics of recovery at both functional and morphological levels after acute copper exposure, unilateral exposure of goldfish olfactory epithelia to 100 μM CuSO4 (10 min) was followed by electro-olfactogram (EOG) recording and scanning electron microscopy. Sensitivity to amino acids (L-arginine and L-serine), generally considered food-related odorants, recovered most rapidly (three days), followed by that to catecholamines(3-O-methoxytyramine),bileacids(taurolithocholic acid) and the steroid pheromone, 17,20 -dihydroxy-4-pregnen- 3-one 20-sulfate, which took 28 days to reach full recovery. Sensitivity to the postovulatory pheromone prostaglandin F2R had not fully recovered even at 28 days. These changes in sensitivity were correlated with changes in the recovery of ciliated and microvillous receptor cell types. Microvillous cells appeared largely unaffected by CuSO4 treatment. Cilia in ciliated receptor neurones, however, appeared damaged one day post-treatment and were virtually absent after three days but had begun to recover after 14 days. Together, these results support the hypothesis that microvillous receptor neurones detect amino acids whereas ciliated receptor neurones were not functional and are responsible for detection of social stimuli (bile acidsandpheromones).Furthermore, differences in sensitivity to copper may be due to different transduction pathways in the different cell types
    corecore