38,830 research outputs found

    Improving announcement media for technical reports

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    Computer and photographic printing and publishing methods for announcing technical report literatur

    The introduction of microfiche for disseminating technical information in the United States

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    Development of microfiche for disseminating technical informatio

    Sculplexity: Sculptures of Complexity using 3D printing

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    We show how to convert models of complex systems such as 2D cellular automata into a 3D printed object. Our method takes into account the limitations inherent to 3D printing processes and materials. Our approach automates the greater part of this task, bypassing the use of CAD software and the need for manual design. As a proof of concept, a physical object representing a modified forest fire model was successfully printed. Automated conversion methods similar to the ones developed here can be used to create objects for research, for demonstration and teaching, for outreach, or simply for aesthetic pleasure. As our outputs can be touched, they may be particularly useful for those with visual disabilities.Comment: Free access to article on European Physics Letter

    MAGMA: a 3D, Lagrangian magnetohydrodynamics code for merger applications

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    We present a new, completely Lagrangian magnetohydrodynamics code that is based on the SPH method. The equations of self-gravitating hydrodynamics are derived self-consistently from a Lagrangian and account for variable smoothing length (``grad-h''-) terms in both the hydrodynamic and the gravitational acceleration equations. The evolution of the magnetic field is formulated in terms of so-called Euler potentials which are advected with the fluid and thus guarantee the MHD flux-freezing condition. This formulation is equivalent to a vector potential approach and therefore fulfills the ∇⃗⋅B⃗=0\vec{\nabla}\cdot\vec{B}=0-constraint by construction. Extensive tests in one, two and three dimensions are presented. The tests demonstrate the excellent conservation properties of the code and show the clear superiority of the Euler potentials over earlier magnetic SPH formulations.Comment: 18 pages, 17 Figures, a high resolution copy of the paper can be found at http://www.faculty.iu-bremen.de/srosswog/MAGMA.pd

    The shapes of the circumstellar silicate features

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    Around oxygen-rich stars the spectra of most long-period variables (LPV) show an excess infrared emission which is attributed to circumstellar silicate dust grains. It is known that the spectral energy distribution of the 10 micron emissions shows variations from star to star. With the availability of many Infrared Astronomy Satellite (IRAS) Low Resolution Spectra (LRS) in the 8 to 22 micron region, the 10 micron feature can be studied to determine its uniformity (or lack thereof). The excess silicate emissions (10 micron emission), divided into three groups characterized by similar spectral shapes, are discussed

    Dynamic stability study for sounding rockets Final report

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    Joint rotation and compliance, body and fin flexibility, and aerodynamic characteristics effect on roll resonance of sounding rocket
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