17,146 research outputs found

    Analysis of Problems Encountered in R and D Project Management

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    Types and frequencies of problems encountered by project and laboratory managers working on 32 government-supported projects in aerospace and electronics industrie

    Individual and corporate sources of motivation - A preliminary investigation

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    Rating scales of individual and corporate motivations and factor analysis of result

    Motivation of R and D enterpreneurs - Determinants of company success

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    Human performance related to motivations of achievement, power, and company affiliations for determining leadership qualitie

    Three-dimensional calculation of shuttle charging in polar orbit

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    The charged particles environment in polar orbit can be of sufficient intensity to cause spacecraft charging. In order to gain a quantitative understanding of such effects, the Air Force is developing POLAR, a computer code which simulates in three dimensions the electrical interaction of large space vehicles with the polar ionospheric plasma. It models the physical processes of wake generation, ambient ion collection, precipitating auroral electron fluxes, and surface interactions, including secondary electron generation and backscattering, which lead to vehicle charging. These processes may be followed dynamically on a subsecond timescale so that the rapid passage through intense auroral arcs can be simulated. POLAR models the ambient plasma as isotropic Maxwellian electrons and ions (0+, H+), and allows for simultaneous precipitation of power-law, energetic Maxwellian, and accelerated Gaussian distributions of electrons. Magnetic field effects will be modeled in POLAR but are currently ignored

    Zeta-Functions for Non-Minimal Operators

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    We evaluate zeta-functions ζ(s)\zeta(s) at s=0s=0 for invariant non-minimal 2nd-order vector and tensor operators defined on maximally symmetric even dimensional spaces. We decompose the operators into their irreducible parts and obtain their corresponding eigenvalues. Using these eigenvalues, we are able to explicitly calculate ζ(0)\zeta(0) for the cases of Euclidean spaces and NN-spheres. In the NN-sphere case, we make use of the Euler-Maclaurin formula to develop asymptotic expansions for the required sums. The resulting ζ(0)\zeta(0) values for dimensions 2 to 10 are given in the Appendix.Comment: 26 pages, additional reference

    Mechanism for the Suppression of Intermediate-Mass Black Holes

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    A model for the formation of supermassive primordial black holes in galactic nuclei with the simultaneous suppression of the formation of intermediate-mass black holes is presented. A bimodal mass function for black holes formed through phase transitions in a model with a "Mexican hat" potential has been found. The classical motion of the phase of a complex scalar field during inflation has been taken into account. Possible observational manifestations of primordial black holes in galaxies and constraints on their number are discussed.Comment: 12 pages, 2 figure

    Domain Bubbles of Extra Dimensions

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    ``Dimension bubbles'' of the type previously studied by Blau and Guendelman [S.K. Blau and E.I. Guendelman, Phys. Rev. D40, 1909 (1989)], which effectively enclose a region of 5d spacetime and are surrounded by a region of 4d spacetime, can arise in a 5d theory with a compact extra dimension that is dimensionally reduced to give an effective 4d theory. These bubbles with thin domain walls can be stabilized against total collapse in a rather natural way by a scalar field which, as in the case with ``ordinary'' nontopological solitons, traps light scalar particles inside the bubble.Comment: 13 pages, no figures; to appear in Phys.Rev.
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