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Mechanical Engineering Commons™

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2008

Selected Works

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Articles 61 - 65 of 65

Full-Text Articles in Mechanical Engineering

Enhanced Stability Of A Dewetting Thin Liquid Film In A Single-Frequency Vibration Field, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev Jan 2008

Enhanced Stability Of A Dewetting Thin Liquid Film In A Single-Frequency Vibration Field, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev

Mikhail Khenner

Dynamics of a thin dewetting liquid film on a vertically oscillating substrate is considered. We assume moderate vibration frequency and large (compared to the mean film thickness) vibration amplitude. Using the lubrication approximation and the averaging method, we formulate the coupled sets of equations governing the pulsatile and the averaged fluid flows in the film, and then derive the nonlinear amplitude equation for the averaged film thickness. We show that there exists a window in the frequency-amplitude domain where the parametric and shear-flow instabilities of the pulsatile flow do not emerge. As a consequence, in this window the averaged description …

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Absolute Phase-Assisted Three-Dimensional Data Registration For A Dual-Camera Structured Light System, Song Zhang, Shing-Tung Yau Jan 2008

Absolute Phase-Assisted Three-Dimensional Data Registration For A Dual-Camera Structured Light System, Song Zhang, Shing-Tung Yau

Song Zhang

For a three-dimensional shape measurement system with a single projector and multiple cameras, registering patches from different cameras is crucial. Registration usually involves a complicated and time-consuming procedure. We propose a new method that can robustly match different patches via absolute phase without significantly increasing its cost. For y and z coordinates, the transformations from one camera to the other are approximated as third-order polynomial functions of the absolute phase. The x coordinates involve only translations and scalings. These functions are calibrated and only need to be determined once. Experiments demonstrated that the alignment error is within RMS 0.7 mm …

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Melt Dispersion Versus Diffusive Oxidation Mechanism For Aluminum Nanoparticles: Critical Experiments And Controlling Parameters, Valery I. Levitas, Michelle L. Pantoya, Birce Dikici Dec 2007

Melt Dispersion Versus Diffusive Oxidation Mechanism For Aluminum Nanoparticles: Critical Experiments And Controlling Parameters, Valery I. Levitas, Michelle L. Pantoya, Birce Dikici

Birce Dikici Ph.D

Critical experiments were performed on Al and MoO3 thermites. The diameter and alumina shell thickness of the Alnanoparticles were varied, and flame propagation velocities were measured. The results strongly support the melt-dispersion mechanism and contradict the diffusionoxidation mechanism. The parameters that control the oxidation rate and flame velocity are justified and directions for the synthesis of Alnanoparticles (which are opposite to the current directions based on diffusionoxidation) are suggested. An equation for the flame velocity versus Alnanoparticle geometrical parameters, thermomechanical properties, and synthesis parameters is formulated.

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Byzantium Beneath The Black Sea, Bridget Buxton, Robert Ballard, Michael Brennan, Dwight Coleman, Katy Croff, Christopher Roman, Dan Davis, Dennis Piechota, Sergiy Voronov Dec 2007

Byzantium Beneath The Black Sea, Bridget Buxton, Robert Ballard, Michael Brennan, Dwight Coleman, Katy Croff, Christopher Roman, Dan Davis, Dennis Piechota, Sergiy Voronov

Christopher N. Roman

This poster reports on the August 2007 Black Sea Expedition of the Institute for Archaeological Oceanography at the University of Rhode Island (IAO) and the Institute for Exploration (IFE), in collaboration with the Department of the Underwater Heritage of Ukraine. This year’s work marks a new phase in a multi-year (2000–2012) archaeological and oceanographic survey of the Black Sea. 2007 fieldwork focuses on two Byzantine shipwrecks. The 10th century C.E. shipwreck Chersonesos A (discovered in 2006) lies at 140 m depth in the suboxic zone off the Crimean peninsula. The ship carried a cargo of one-handled jars of a widely …

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Validity Of The One-Dimensional Limp Model For Porous Media, Olivier Doutres, Nicolas Dauchez, Jean-Michel Génevaux, Olivier Dazel Dec 2007

Validity Of The One-Dimensional Limp Model For Porous Media, Olivier Doutres, Nicolas Dauchez, Jean-Michel Génevaux, Olivier Dazel

Olivier Doutres Ph.D.

A straightforward criterion for determining the validity of the limp model validity for porous materials is addressed here. The limp model is an “equivalent fluid” model which gives a better description of porous behavior than the well known “rigid frame” model. It is derived from the poroelastic Biot model, assuming that the frame has no bulk stiffness. A criterion is proposed for identifying the porous materials for which the limp model can be used. It relies on a new parameter, the Frame Stiffness Influence FSI, based on porous material properties. The critical values of FSI under which the limp model …

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