1,733 research outputs found

    Entangled granular media

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    We study the geometrically induced cohesion of ensembles of granular "u-particles" which mechanically entangle through particle interpenetration. We vary the length-to-width ratio l/wl/w of the u-particles and form them into free-standing vertical columns. In laboratory experiment we monitor the response of the columns to sinusoidal vibration (frequency ff, peak acceleration Γ\Gamma). Column collapse occurs in a characteristic time, τ\tau, which follows the relation τ=f1exp(Δ/Γ)\tau = f^{-1} \exp(\Delta / \Gamma). Δ\Delta resembles an activation energy and is maximal at intermediate l/wl/w. Simulation reveals that optimal strength results from competition between packing and entanglement.Comment: 4 pages, 5 figure

    An evaluation of the coal and electric utilities model documentation

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    Review Article: Recent Research On the Military in Society

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    The Social Psychology of Military Service; Sage Research Progress Series on War, Revolution, and Peacekeeping; Vol. VI, Young Men and Military Service; Vol. V, Youth in Transition, and The Soldier and Social Change; Comparative Studies in the History and Sociology of the Militar
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