42,002 research outputs found

    Design of an atmospheric sounding radiometer for the GOES meteorological satellite system

    Get PDF
    An advanced version of the visible infrared spin scan radiometer onboard U.S. geostationary operational environmental satellites was developed to add a vertical dimension to the instrument's infrared atmospheric images. Through the addition of twelve selectable narrow band filters and more precise in-flight calibration of the infrared detectors, the VISSR atmospheric sounder (VAS) will provide increased data to help determine the Earth's atmospheric temperature and water vapor distribution. The radiometer design, filter wheel, calibration shutter mechanisms, and their preflight test performance are discussed

    Thermal radiation analysis system TRASYS 2: User's manual

    Get PDF
    The Thermal Radiation Analyzer System (TRASYS) program put thermal radiation analysis on the same basis as thermal analysis using program systems such as MITAS and SINDA. The user is provided the powerful options of writing his own executive, or driver logic and choosing, among several available options, the most desirable solution technique(s) for the problem at hand. This User's Manual serves the twofold purpose of instructing the user in all applications and providing a convenient reference book that presents the features and capabilities in a concise, easy-to-find manner

    A solvable non-conservative model of Self-Organized Criticality

    Full text link
    We present the first solvable non-conservative sandpile-like critical model of Self-Organized Criticality (SOC), and thereby substantiate the suggestion by Vespignani and Zapperi [A. Vespignani and S. Zapperi, Phys. Rev. E 57, 6345 (1998)] that a lack of conservation in the microscopic dynamics of an SOC-model can be compensated by introducing an external drive and thereby re-establishing criticality. The model shown is critical for all values of the conservation parameter. The analytical derivation follows the lines of Broeker and Grassberger [H.-M. Broeker and P. Grassberger, Phys. Rev. E 56, 3944 (1997)] and is supported by numerical simulation. In the limit of vanishing conservation the Random Neighbor Forest Fire Model (R-FFM) is recovered.Comment: 4 pages in RevTeX format (2 Figures) submitted to PR

    Comment on `Series expansions from the corner transfer matrix renormalization group method: the hard-squares model'

    Full text link
    Earlier this year Chan extended the low-density series for the hard-squares partition function κ(z)\kappa(z) to 92 terms. Here we analyse this extended series focusing on the behaviour at the dominant singularity zdz_d which lies on on the negative fugacity axis. We find that the series has a confluent singularity of order 2 at zdz_d with exponents θ=0.83333(2)\theta=0.83333(2) and θ′=1.6676(3)\theta'= 1.6676(3). We thus confirm that the exponent θ\theta has the exact value 56\frac56 as observed by Dhar.Comment: 5 pages, 1 figure, IoP macros. Expanded second and final versio

    Synthesis of imide/arylene ether copolymers for adhesives and composite matrices

    Get PDF
    A series of imide/arylene ether copolymers were prepared from the reaction of an amorphous arylene ether oligomer and a semi-crystalline imide oligomer. These copolymers were thermally characterized and mechanical properties were measured. One block copolymer was endcapped and the molecular weight was controlled to provide a material that displayed good compression moldability and attractive adhesion and composite properties

    A numerical adaptation of SAW identities from the honeycomb to other 2D lattices

    Full text link
    Recently, Duminil-Copin and Smirnov proved a long-standing conjecture by Nienhuis that the connective constant of self-avoiding walks on the honeycomb lattice is 2+2.\sqrt{2+\sqrt{2}}. A key identity used in that proof depends on the existence of a parafermionic observable for self-avoiding walks on the honeycomb lattice. Despite the absence of a corresponding observable for SAW on the square and triangular lattices, we show that in the limit of large lattices, some of the consequences observed on the honeycomb lattice persist on other lattices. This permits the accurate estimation, though not an exact evaluation, of certain critical amplitudes, as well as critical points, for these lattices. For the honeycomb lattice an exact amplitude for loops is proved.Comment: 21 pages, 7 figures. Changes in v2: Improved numerical analysis, giving greater precision. Explanation of why we observe what we do. Extra reference

    Rolling of asymmetric disks on an inclined plane

    Full text link
    In a recent papers, Turner and Turner (2010 {\em Am. J. Phys.} {\bf 78} 905-7) and Jensen (2011 {\em Eur. J. Phys.} {\bf 32} 389-397) analysed the motion of asymmetric rolling rigid bodies on a horizontal plane. These papers addressed the common misconception that the instantaneous point of contact of the rolling body with the plane can be used to evaluate the angular momentum L\mathbf L and the torque Ï„\boldsymbol\tau in the equation of motion dL/dt=Ï„d\mathbf L/dt = \boldsymbol\tau. To obtain the correct equation of motion, the "phantom torque" or various rules that depend on the motion of the point about which L\mathbf L and Ï„\boldsymbol\tau are evaluated were discussed. In this paper, I consider asymmetric disks rolling down an inclined plane and describe the most basic way of obtaining the correct equation of motion; that is, to choose the point about which L\mathbf L and Ï„\boldsymbol\tau are evaluated that is stationary in an inertial frame
    • …
    corecore