47 research outputs found

    The Nonlinear Stability of a Heavy Rigid Plate Supported by Flexible Columns

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    A heavy rigid platform is supported by thin elastic legs. The governing equations for large deformations are formulated and solved numerically by homotopy and quasi-Newton methods. Nonlinear phenomena such as non-uniqueness, catastrophe and hysteresis are found. A global critical load for nonlinear stability is introduced

    Magnetohydrodynamic Flow Past a Porous Rotating Disk In a Circular Magnetic Field

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    This paper studies the effects of a circular magnetic field on the flow of a conducting fluid about a porous rotating disk. Using modern quasi-Newton and globally convergent homotopy methods, numerical solutions are obtained for a wide range of magentic field strengths, suction and injection velocities and Alfven and disk speeds. Results are presented graphically in terms of three nondimensional parameters. There is excellent agreement with previous work and asymptotic formulas

    Magnetohydrodynamic Flow and Heat Transfer About a Rotating Disk with Suction and Injection at the Disk Surface

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    This paper studies the effects of a partial magnetic field on the flow and heat transfer about a porous rotating disk. Using modem quasi-Newton and globally convergent homotopy methods, numerical solutions are obtained for a wide range of magnetic field strengths and injection and suction velocities. Results are presented graphically in terms of three nondimensional parameters. There is excellent agreement with previous work and asymptotic formulas

    Magnetohydrodynamic Flow Between a Solid Rotating Disk and a Porous Stationary Disk

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    In this paper we examine the flow of a conducting fluid between a solid rotating disk and a stationary porous disk with uniform section of fluid through the porous disk in the presence of a magnetic fiels. The equations of motion are solved using least change secant update quasi-Newton and modern root finding techniques. The fluid motion depends on the cross-flow Reynolds number, rotation Reynolds number and Hartmann number. The effects of the parameters on the flow field are presented graphically

    Algorithm XXX: SHEPPACK: Modified Shepard Algorithm for Interpolation of Scattered Multivariate Data

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    Scattered data interpolation problems arise in many applications. Shepard’s method for constructing a global interpolant by blending local interpolants using local-support weight functions usually creates reasonable approximations. SHEPPACK is a Fortran 95 package containing five versions of the modified Shepard algorithm: quadratic (Fortran 95 translations of Algorithms 660, 661, and 798), cubic (Fortran 95 translation of Algorithm 791), and linear variations of the original Shepard algorithm. An option to the linear Shepard code is a statistically robust fit, intended to be used when the data is known to contain outliers. SHEPPACK also includes a hybrid robust piecewise linear estimation algorithm RIPPLE (residual initiated polynomial-time piecewise linear estimation) intended for data from piecewise linear functions in arbitrary dimension m. The main goal of SHEPPACK is to provide users with a single consistent package containing most existing polynomial variations of Shepard’s algorithm. The algorithms target data of different dimensions. The linear Shepard algorithm, robust linear Shepard algorithm, and RIPPLE are the only algorithms in the package that are applicable to arbitrary dimensional data

    Magnetohydrodynamic flow and heat transfer about a rotating disk with suction and injection at the disk surface

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    This paper studies the effects of an axial magnetic field on the flow and heat transfer about a porous rotating disk. Using modern quasi-Newton and globally convergent homotopy methods, numerical solutions are obtained for a wide range of magnetic field strengths and injection and suction velocities. Results are presented graphically in terms of three nondimensional parameters. There is excellent agreement with previous work and asymptotic formulas.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27498/1/0000542.pd

    The ATLAS inner detector trigger performance in pp collisions at 13 TeV during LHC Run 2

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    The design and performance of the inner detector trigger for the high level trigger of the ATLAS experiment at the Large Hadron Collider during the 2016-18 data taking period is discussed. In 2016, 2017, and 2018 the ATLAS detector recorded 35.6 fb1^{-1}, 46.9 fb1^{-1}, and 60.6 fb1^{-1} respectively of proton-proton collision data at a centre-of-mass energy of 13 TeV. In order to deal with the very high interaction multiplicities per bunch crossing expected with the 13 TeV collisions the inner detector trigger was redesigned during the long shutdown of the Large Hadron Collider from 2013 until 2015. An overview of these developments is provided and the performance of the tracking in the trigger for the muon, electron, tau and bb-jet signatures is discussed. The high performance of the inner detector trigger with these extreme interaction multiplicities demonstrates how the inner detector tracking continues to lie at the heart of the trigger performance and is essential in enabling the ATLAS physics programme
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