5,011 research outputs found

    Gas turbine engine with convertible accessories

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    Drive means for connecting a gas turbine engine to its accessories are so constructed as to allow the accessories to be selectively positioned to any one of several predetermined circumferential positions about the perimeter of the engine. This feature permits convenient mounting of the same engine upon vehicles demanding radically different engine mounting arrangements

    The 3 micron spectrum of NGC 4565

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    Researchers spectrum of NGC 4565 is essentially featureless. The absence of the 3.0 micron feature (Tau 3.0 less than 0.05) implies that the extinction to the nucleus does not arise to a significant degree in molecular clouds. Researchers deduce Tau 3.0/A sub V less than 0.01, compared with approx. 0.022 for GC-IRS7. These results support the conclusion (McFadzean et al. 1989) that the 3.0 micron absorption in the GC-IR sources is due to the presence of ice in a (probably single) foreground molecular cloud. The 3.4 micron feature is also weak or absent in the researchers spectrum of NGC 4565 (Tau 3.4 less than or equal to 0.07), hence, Tau 3.4/A sub V less than or equal to 0.016, compared with approx. 0.008 towards GC-IRS7. The absence of the feature in NGC 4565 at the signal-to-noise level of the current observations is consistent with a probable moderate degree of extinction towards the nucleus. The observations of NGC 4565 provide a useful comparison for studies of dust in the Galaxy. Limits have been set on the strengths of the 3.0 and 3.4 micron features in NGC 4565. The absence of 3.0 micron absorption is significant, and supports the view that the feature at this wavelength in the Galactic Centre is due to water-ice absorption in a foreground molecular cloud. The non-detection of the 3.4 micron absorption is less surprising and provides indirect support for the association between this feature and the diffuse interstellar medium. The current spectrum probably represents the best that can be achieved with a single-detector instrument within reasonable integration times. It will clearly be of interest in the future to obtain spectra of higher signal-to-noise, as a positive detection of the 3.4 micron feature in an external galaxy, even at a low level, would be of considerable astrophysical significance

    Integrated gas turbine engine-nacelle

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    A nacelle for use with a gas turbine engine is provided with an integral webbed structure resembling a spoked wheel for rigidly interconnecting the nacelle and engine. The nacelle is entirely supported in its spacial relationship with the engine by means of the webbed structure. The inner surface of the nacelle defines the outer limits of the engine motive fluid flow annulus, while the outer surface of the nacelle defines a streamlined envelope for the engine

    Integrated gas turbine engine-nacelle

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    A nacelle for use with a gas turbine engine is presented. An integral webbed structure resembling a spoked wheel for rigidly interconnecting the nacelle and engine, provides lightweight support. The inner surface of the nacelle defines the outer limits of the engine motive fluid flow annulus while the outer surface of the nacelle defines a streamlined envelope for the engine

    Results of magnetospheric barium ion cloud experiment of 1971

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    The barium ion cloud experiment involved the release of about 2 kg of barium at an altitude of 31 482 km, a latitude of 6.926 N., and a longitude of 74.395 W. Significant erosion of plasma from the main ion core occurred during the initial phase of the ion cloud expansion. From the motion of the outermost striational filaments, the electric field components were determined to be 0.19 mV/m in the westerly direction and 0.68 mV/m in the inward direction. The differences between these components and those measured from balloons flown in the proximity of the extremity of the field line through the release point implied the existence of potential gradients along the magnetic field lines. The deceleration of the main core was greater than theoretically predicted. This was attributed to the formation of a polarization wake, resulting in an increase of the area of interaction and resistive dissipation at ionospheric levels. The actual orientation of the magnetic field line through the release point differed by about 10.5 deg from that predicted by magnetic field models that did not include the effect of ring current

    Uncovering Spiral Structure in Flocculent Galaxies

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    We present K'(2.1 micron) observations of four nearby flocculent spirals, which clearly show low-level spiral structure and suggest that kiloparsec-scale spiral structure is more prevalent in flocculent spirals than previously supposed. In particular, the prototypical flocculent spiral NGC 5055 is shown to have regular, two-arm spiral structure to a radius of 4 kpc in the near infrared, with an arm-interarm contrast of 1.3. The spiral structure in all four galaxies is weaker than that in grand design galaxies. Taken in unbarred galaxies with no large, nearby companions, these data are consistent with the modal theory of spiral density waves, which maintains that density waves are intrinsic to the disk. As an alternative, mechanisms for driving spiral structure with non-axisymmetric perturbers are also discussed. These observations highlight the importance of near infrared imaging for exploring the range of physical environments in which large-scale dynamical processes, such as density waves, are important.Comment: 12 pages AASTeX; 3 compressed PS figures can be retrieved from ftp://ftp.astro.umd.edu/pub/michele as file thornley.tar (1.6Mbytes). Accepted to Ap.J. Letters.(Figures now also available here, and from ftp://ftp.astro.umd.edu/pub/michele , in GIF format.

    Search for Lorentz Invariance and CPT Violation with the MINOS Far Detector

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    We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be a consequence of Lorentz and CPT violation as described by the standard-model extension framework. It also would be the first detection of a perturbative effect to conventional neutrino mass oscillations. We found no evidence for this sidereal signature, and the upper limits placed on the magnitudes of the Lorentz and CPT violating coefficients describing the theory are an improvement by factors of 20–510 over the current best limits found by using the MINOS near detector

    Improved Measurement of Muon Antineutrino Disappearance in MINOS

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    We report an improved measurement of ν̅_μ disappearance over a distance of 735 km using the MINOS detectors and the Fermilab Main Injector neutrino beam in a ν̅_μ-enhanced configuration. From a total exposure of 2.95×10^20 protons on target, of which 42% have not been previously analyzed, we make the most precise measurement of Δm̅^2=[2.62_(-0.28)^(+0.31)(stat)±0.09(syst)]×10^(-3)  eV^2 and constrain the ν_μ mixing angle sin^(2)(2θ̅)>0.75 (90% C.L.). These values are in agreement with Δm^2 and sin^(2)(2θ) measured for νμ, removing the tension reported in [ P. Adamson et al. Phys. Rev. Lett. 107 021801 (2011)]

    Spectroscopic Evidence for the Specific Na+ and K+ Interactions with the Hydrogen-bonded Water Molecules at the Electrolyte Aqueous Solution Surfaces

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    Sum frequency generation vibrational spectra of the water molecules at the NaF and KF aqueous solution surfaces showed significantly different spectral features and different concentration dependence. This result is the first direct observation of the cation effects of the simple alkali cations, which have been believed to be depleted from the aqueous surface, on the hydrogen bonding structure of the water molecules at the electrolyte solution surfaces. These observations may provide important clue to understand the fundamental phenomenon of ions at the air/water interface.Comment: 15 pages, 2 figure
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