37,465 research outputs found

    Introductory workshops on remote sensing as related to geological problems in Georgia

    Get PDF
    There are no author-identified significant results in this report

    Application of pushbroom altimetry from space using large space antennas

    Get PDF
    The capabilities of multibeam altimetry are discussed and an interferometric multibeam technique for doing precision altimetry is described. The antenna feed horn arrangement and the resulting footprint lube pattern are illustrated. Plans for a shuttle multibeam altimetry mission are also discussed

    Modeling 3-D objects with planar surfaces for prediction of electromagnetic scattering

    Get PDF
    Electromagnetic scattering analysis of objects at resonance is difficult because low frequency techniques are slow and computer intensive, and high frequency techniques may not be reliable. A new technique for predicting the electromagnetic backscatter from electrically conducting objects at resonance is studied. This technique is based on modeling three dimensional objects as a combination of flat plates where some of the plates are blocking the scattering from others. A cube is analyzed as a simple example. The preliminary results compare well with the Geometrical Theory of Diffraction and with measured data

    Horn antenna with v-shaped corrugated surface

    Get PDF
    Corrugated shape is easily machined for millimeter wave application and is better suited for folding antenna designs. Measured performance showed ""V'' corrugations and rectangular corrugations have nearly the same pattern beamwidth, gain, and impedance. Also, ""V'' corrugations have higher relative power loss

    Prospective cognitions in anxiety and depression: Replication and methodological extension

    Get PDF
    The present study presents a replication and methodological extension of MacLeod, Tata, Kentish, and Jacobsen (1997) with a nonclinical sample, using future-directed imagery to assess prospective cognitions. Results showed that only anxiety (but not depression) was related to enhanced imagery for future negative events. Both anxiety and depression showed significant zero-order correlations with reduced imagery for future positive events. However, when the overlap between anxiety and depression was controlled for, only depression (but not anxiety) showed a unique association with reduced imagery for positive events. Implications of these findings for cognitive models of anxiety and depression are discussed

    Transverse electric scattering widths for strips-Fourier transform technique

    Get PDF
    A technique which is based on Fourier transformations is introduced for predicting scattering widths. For a strip it is shown that explicit determination of the linear current density is not necessary for bistatic or monostatic scattering width calculations. Comparisons of the predictions of the technique are made with the integral equation technique predictions, which do not require explicit evaluations of linear current densities

    The population of deformed bands in 48^{48}Cr by emission of 8^{8}Be from the 32^{32}S + 24^{24}Mg reaction

    Full text link
    Using particle-γ\gamma coincidences we have studied the population of final states after the emission of 2 α\alpha-particles and of 8^{8}Be in nuclei formed in 32^{32}S+24^{24}Mg reactions at an energy of EL(32S)=130MeV\textrm{E}_{\rm L}(^{32}\textrm{S}) = 130 {\rm MeV}. The data were obtained in a setup consisting of the GASP γ\gamma-ray detection array and the multidetector array ISIS. Particle identification is obtained from the Δ\DeltaE and E signals of the ISIS silicon detector telescopes, the 8^{8}Be being identified by the instantaneous pile up of the Δ\DeltaE and E pulses. γ\gamma-ray decays of the 48^{48}Cr nucleus are identified with coincidences set on 2 α\alpha-particles and on 8^{8}Be. Some transitions of the side-band with Kπ=4K^\pi=4^{-} show stronger population for 8^{8}Be emission relative to that of 2 α\alpha-particles (by a factor 1.51.81.5-1.8). This observation is interpreted as due to an enhanced emission of 8^{8}Be into a more deformed nucleus. Calculations based on the extended Hauser-Feshbach compound decay formalism confirm this observation quantitatively.Comment: 17 pages, 9 figures accepted for publication in J. Phys.

    Measuring non-extensitivity parameters in a turbulent Couette-Taylor flow

    Full text link
    We investigate probability density functions of velocity differences at different distances r measured in a Couette-Taylor flow for a range of Reynolds numbers Re. There is good agreement with the predictions of a theoretical model based on non-extensive statistical mechanics (where the entropies are non-additive for independent subsystems). We extract the scale-dependent non-extensitivity parameter q(r, Re) from the laboratory data.Comment: 8 pages, 5 figure

    Entrance-channel Mass-asymmetry Dependence of Compound-nucleus Formation Time in Light Heavy-ion Reactions

    Get PDF
    The entrance-channel mass-asymmetry dependence of the compound nucleus formation time in light heavy-ion reactions has been investigated within the framework of semiclassical dissipative collision models. the model calculations have been succesfully applied to the formation of the 38^{38}Ar compound nucleus as populated via the 9^{9}Be+29^{29}Si, 11^{11}B+27^{27}Al, 12^{12}C+26^{26}Mg and 19^{19}F+19^{19}F entrance channels. The shape evolution of several other light composite systems appears to be consistent with the so-called "Fusion Inhibition Factor" which has been experimentally observed. As found previously in more massive systems for the fusion-evaporation process, the entrance-channel mass-asymmetry degree of freedom appears to determine the competition between the different mechanisms as well as the time scales involved.Comment: 12 pages, 3 Figures available upon request, Submitted at Phys. Rev.
    corecore