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Materials Science and Engineering

Wright State University

2005

Articles 1 - 4 of 4

Full-Text Articles in Engineering

Method Of Reducing Internal Stress In Materials, Maher S. Amer, John F. Maguire May 2005

Method Of Reducing Internal Stress In Materials, Maher S. Amer, John F. Maguire

Mechanical and Materials Engineering Faculty Publications

Methods are provided for adjusting and controlling the stress between layers of material in a multilayer structure. A first stress is configured in a region of stress on the substrate material. A second material is then deposited over the substrate. A second stress results between the substrate and the second material such that a net stress results where the net stress is a function of said first and second stresses. As such, the first stress can be configured to achieve a predetermined, desired net stress. For example, the first stress can be configured to cancel out the second stress such …


Slip Behavior In Liquid Films On Surfaces Of Patterned Wettability: Comparison Between Continuum And Molecular Dynamics Simulations, Nikolai V. Priezjev, Anton A. Darhuber, Sandra M. Troian Apr 2005

Slip Behavior In Liquid Films On Surfaces Of Patterned Wettability: Comparison Between Continuum And Molecular Dynamics Simulations, Nikolai V. Priezjev, Anton A. Darhuber, Sandra M. Troian

Mechanical and Materials Engineering Faculty Publications

We investigate the behavior of the slip length in Newtonian liquids subject to planar shear bounded by substrates with mixed boundary conditions. The upper wall, consisting of a homogenous surface of finite or vanishing slip, moves at a constant speed parallel to a lower stationary wall, whose surface is patterned with an array of stripes representing alternating regions of no shear and finite or no slip. Velocity fields and effective slip lengths are computed both from molecular dynamics (MD) simulations and solution of the Stokes equation for flow configurations either parallel or perpendicular to the stripes. Excellent agreement between the …


Unsteady Tip Leakage, Bow Shock, Igv Wake Interaction In A Compressor, Xuedong Zhou, J. Mitch Wolff Jan 2005

Unsteady Tip Leakage, Bow Shock, Igv Wake Interaction In A Compressor, Xuedong Zhou, J. Mitch Wolff

Mechanical and Materials Engineering Faculty Publications

Unsteady aerodynamic analysis of Inlet Guide Vane (IGV)/rotor interaction is conducted with a commercial CFD solver, STAR-CD. 12% and 26% IGV axial chord IGV/Rotor spacing configurations were examined for 100% corrected speed at choke, peak efficiency and near stall conditions to investigate bow shock/tip leakage interaction within blade rows. Comparison with IGV surface unsteady pressure experimental data indicates good agreement at the IGV trailing edge across the span for both spacing configurations; therefore, validating the modeling of the high speed, highly loaded transonic compressor. The strongest effect on the tip clearance flow physics was caused by decreasing the axial spacing. …


Vibrational Behavior Of The MN+1AxN Phases From First-Order Raman Scattering (M=Ti,V,Cr, A=Si, X=C,N), Jonathan E. Spanier, Surojit Gupta, Maher S. Amer, Michel W. Barsoum Jan 2005

Vibrational Behavior Of The MN+1AxN Phases From First-Order Raman Scattering (M=Ti,V,Cr, A=Si, X=C,N), Jonathan E. Spanier, Surojit Gupta, Maher S. Amer, Michel W. Barsoum

Mechanical and Materials Engineering Faculty Publications

We report on the Raman spectra of Ti3SiC2 (312), M2AlC(211) (M=Ti, V, Cr, and Nb) and Ti4AlN3 (413), as representative compounds from the family of Mn+1AXn phases. Intense and narrow first-order Raman peaks are observed, and we present an analysis of the spectra based on symmetry considerations and from results of first-principles calculations of phonon frequencies. The agreement between experimental and calculated mode energies is excellent. The identification of the modes enables application of Raman scattering as a diagnostic tool for the detailed study of the structural and physical properties of this family of compounds and their …