91,880 research outputs found

    Analysis for leakage and rotordynamic coefficients of surface roughened tapered annular gas seals

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    In order to soften the effects of rub, the smooth stators of turbine gas seals are sometimes replaced by a honeycomb surface. This deliberately roughened stator and smooth rotor combination retards the seal leakage and may lead to enhanced rotor stability. However, many factors determine the rotordynamic coefficients and little is known as to the effectiveness of these honeycomb seals under various changes in the independent seal parameters. An analytical-computational method to solve for the rotordynamic coefficients of this type of compressible-flow seal is developed. The governing equations for surface roughned tapered annular gas seals are based on a modified Hirs' turbulent bulk flow model. A perturbation analysis is employed to develop zeroth and first-order perturbation equations. These equations are numerically integrated to solve for the leakage, pressure, density, and velocity for small motion of the shaft about the centered position. The resulting pressure distribution is then integrated to find the corresponding rotor-dynamic coefficients

    X-ray determination of parts alignment

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    A method for determining the alignment of adjoining metal objects is provided. The method comprises producing an X-ray image of adjoining surfaces of the two metal objects. The X-ray beam is tangential to the point the surfaces are joined. The method is particularly applicable where the alignment of the two metal objects is not readily susceptible to visual inspection

    Options for Regional Decision Making in Metro Atlanta

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    Who loses if nothing is done? The city of Atlanta, with its central location, mature transit network, excess capacity in utilities, and reasonably aggressive public officials will probably thrive no matter what happens outside the I-285 perimeter. Communities outside the boundaries of the ten-county Atlanta Regional Commission (ARC) area will enjoy the temporary fruits of being the next ring of new suburban development. Caught between the Atlanta magnet and the sprawling communities outside the ARC, ARC's suburban communities may bear the worst of the downside effects of the current regional decision-making structure. In the end, though, it is all of North Georgia that loses as congestion, pollution, rising taxes, and reduced quality of life diminish its attractiveness to economic development

    Reentry communication by material addition Patent

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    Reentry communication by injection of water droplets into plasma layer surrounding space vehicl

    Ending marriage, keeping faith: a new guide through the spiritual journey of divorce

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    Reviewed Book: Nichols, J Randall. Ending marriage, keeping faith: a new guide through the spiritual journey of divorce. New York: Crossroad, 1993

    Colloidal particle motion as a diagnostic of DNA conformational transitions

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    Tethered particle motion is an experimental technique to monitor conformational changes in single molecules of DNA in real time, by observing the position fluctuations of a micrometer-size particle attached to the DNA. This article reviews some recent work on theoretical problems inherent in the interpretation of TPM experiments, both in equilibrium and dynamical aspects.Comment: 19pp. Accepted for publication in Curr Op Colloid Interf Scienc
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