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Fabrication And Characterization Of Silver- And Copper-Coated Nylon 6 Forcespun Nanofibers By Thermal Evaporation, Dorina M. Mihut, Karen Lozano, Heinrich D. Foltz Oct 2014

Fabrication And Characterization Of Silver- And Copper-Coated Nylon 6 Forcespun Nanofibers By Thermal Evaporation, Dorina M. Mihut, Karen Lozano, Heinrich D. Foltz

Mechanical Engineering Faculty Publications and Presentations

Silver and copper nanoparticles were deposited as thin films onto substrates consisting of Nylon 6 nanofibers manufactured using forcespinningR equipment. Different rotational speeds were used to obtain continuous nanofibers of various diameters arranged as nonwoven mats. The Nylon 6 nanofibers were collected as successive layers on frames, and a high-vacuum thermal evaporation method was used to deposit the silver and copper thin films on the nanofibers. The structures were investigated using scanning electron microscopy–scanning transmission electron microscopy, atomic force microscopy, x-ray diffraction, and electrical resistance measurements. The results indicate that evaporated silver and copper nanoparticles were successfully deposited on Nylon …


Long-Lasting Effect Of Initial Configuration In Gravitational Spreading Of Material Fronts, ‪Nadim Zgheib, Thomas Bonometti, S. Balachandar Sep 2014

Long-Lasting Effect Of Initial Configuration In Gravitational Spreading Of Material Fronts, ‪Nadim Zgheib, Thomas Bonometti, S. Balachandar

Mechanical Engineering Faculty Publications and Presentations

We present the results from laboratory experiments and fully resolved simulations pertaining to finite-release turbulent density flows with a non-axisymmetric initial shape. First, we demonstrate that the effects of the initial shape influence the current’s evolution well into the long-time phase which would corresponds to the inertial self-similar phase in the case of planar or axisymmetric configurations. Then, we identify the physical mechanisms responsible for this dependence and propose a new model capable of capturing the dynamics of such releases. Finally, we show that this dependence on the initial configuration is robust for various types of gravity currents over a …


Bifurcation Type Change Of Ac Electrostatically Actuated Mems Resonators Due To Dc Bias, Dumitru Caruntu, Kyle N. Taylor Apr 2014

Bifurcation Type Change Of Ac Electrostatically Actuated Mems Resonators Due To Dc Bias, Dumitru Caruntu, Kyle N. Taylor

Mechanical Engineering Faculty Publications and Presentations

This paper investigates the nonlinear response of microelectromechanical system (MEMS) cantilever resonator electrostatically actuated by applying a soft alternating current (AC) voltage and an even softer direct current (DC) voltage between the resonators and a parallel fixed ground plate. The AC frequency is near natural frequency. This drives the resonator into nonlinear parametric resonance. The method ofmultiple scales (MMS) is used to solve the dimensionless differential equation of motion of the resonator and find the steady-state solutions.The reduced order model (ROM) method is used to validate the results obtained using MMS. The effect of the soft DC voltage (bias) component …


Unidirectional Rotary Tendency Of A Wave-Driven Rotor, Yingchen Yang Jan 2014

Unidirectional Rotary Tendency Of A Wave-Driven Rotor, Yingchen Yang

Mechanical Engineering Faculty Publications and Presentations

Ocean waves can directly drive WECs (wave energy converters) to perform two types of motion—reciprocating motion and unidirectional rotary motion. In general, the efficiency of a reciprocating WEC is strongly wave-frequency dependent, whereas the efficiency of a rotary WEC can be somewhat wave-frequency independent. To date, a huge majority of WEC technologies under development in industry belong to the reciprocating class, and only a few WEC concepts fall in the unidirectional rotary class. In the present work, a wave-driven rotor for unidirectional rotary motion was proposed and characterized. A numerical tool has been developed for characterization of the rotor’s unidirectional …