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Displaying 1701 - 1725 of 2146

Computational study of the dielectric properties of [La,Sc] 2 O 3 solid solutions

July 11, 2010
Author(s)
Hiroyoshi Momida, Eric J. Cockayne, Naoto Umezawa, Takahisa Ohno
First-principles calculations were used to compute the dielectric permittivities of hypothetical [La,Sc]2O3 solid solutions in the cubic (bixbyite) and hexagonal La2O3 phases. Dielectric enhancement is predicted at small Sc concentrations due to the

Modeling Reactive Wetting when Inertial Effects are Dominant

June 30, 2010
Author(s)
Daniel Wheeler, James A. Warren, William J. Boettinger
Recent experimental studies of molten metal droplets wetting and spreading on high temperature reactive substrates have established that the majority of triple-line motion occurs when inertial effects are dominant. In light of these studies, this paper

Thermodynamic model of hydride formation and dissolution in spherical particles

June 30, 2010
Author(s)
Yuri Mishin, William J. Boettinger
A model of hydride formation and dissolution has been proposed for a single spherical nano-particle and for a colletion of such particles with a given size distribution. The phase transformation strain gives rise to an elastic barrier of the transformation

Multi-Scale Pore Morphology in Vapor-Deposited Yttria-Stabilized Zirconia Coatings

June 16, 2010
Author(s)
Derek D. Hass, H. Zhao, Tabbetha A. Dobbins, Andrew J. Allen, Andrew Slifka, H. N. Wadley
A high pressure, electron-beam directed-vapor deposition process has been used to deposit partially stabilized zirconia containing 7 % yttria by mass at deposition pressures of 7.5 Pa to 23 Pa. Anisotropic ultra-small-angle X-ray scattering (USAXS) was

Tooth chipping can reveal bite forces and diets of fossil hominins

June 16, 2010
Author(s)
Paul Constantino, James J. Lee, H Chai, Bernhard Zipfel, Charles Ziscovici, Brian R. Lawn, Peter Lucas
Fossil hominin tooth enamel often exhibits antemortem edge chipping (Robinson 1954; Tobias 1967; Wallace 1973). Here we apply a simple fracture equation to estimate peak bite forces from the sizes of such chips. This equation, previously validated by

Role of Nanoparticles in Life Cycle of Nanocomposites

June 15, 2010
Author(s)
Xiaohong Gu, Guodong Chen, Minhua Zhao, Stephanie S. Watson, Paul E. Stutzman, Tinh Nguyen, Joannie W. Chin, Jonathan W. Martin
The objective of this study is to investigate the role of ZnO nanoparticles in the life cycle of a waterborne polyurethane (PU) nanocomposite during UV exposure. The effects of loadings and sizes of ZnO nanoparticles on photodegradation of ZnO/PU films

Dynamic Deformation of Jacketed Lead Bullets Captured By High Speed DIC

June 7, 2010
Author(s)
Steven P. Mates
The development of high fidelity simulations of lead-cored bullet impacts on soft body armor, motivated by the need for improved armor designs and performance standards for law enforcement, requires accurate models for both the armor and the deformable

A Multicomponent and Multiphase Model of Reactive Wetting

June 4, 2010
Author(s)
Walter Villanueva, William J. Boettinger, Geoffrey B. McFadden, James A. Warren
A diffuse-interface model of reactive wetting with intermetallic formation is presented. The model incorporates fluid flow, solute diffusion, and phase change that are based on the total molar Gibbs energy of a ternary system with four phases. Numerical

Ultraviolet Weathering of Firefighter Protective Clothing

June 4, 2010
Author(s)
Rick D. Davis, Joannie W. Chin, Chiao-Chi Lin, Sylvain H. Petit
Exposure to simulated ultraviolet sunlight at 50 C and 50 % relative humidity caused a significant deterioration in the mechanical performance of polyaramid and polyaramid/polybenzimidazole based Outer Shell fabrics used in firefighter jacket and pants

Degradation and Nanoparticle Release of Nanocomposite Coatings Exposed to UV Radiation

June 2, 2010
Author(s)
Tinh Nguyen, Bastien T. Pellegrin, Coralie Bernard, Xiaohong Gu, Justin M. Gorham, Paul E. Stutzman, Alexander J. Shapiro, Walter E. Byrd, Joannie W. Chin
The release of nanoparticles from nanocomposite coatings during their life cycle potentially has negative effects to the environments and presents a roadblock to their uses. The degradation and nanoparticle release of amine-cured epoxy coatings containing

Core-shell composite of SiCN and multiwalled carbon nanotubes from Toluene dispersion

May 21, 2010
Author(s)
John H. Lehman, Katherine E. Hurst, Gurpreet Singh, Elisabeth Mansfield, John D. Perkins, Christopher L. Cromer
Carbon nanotubes are known to have high thermal conductivity, and in bulk form, a topology that could constitute the matrix of an inhomogeneous solid. Among the promised applications of carbon nanotubes is a composite material that is practical for thermal

Strength distribution of single-crystal silicon theta-like specimens

May 18, 2010
Author(s)
Michael S. Gaither, Frank W. DelRio, Richard S. Gates, Edwin R. Fuller, Robert F. Cook
A new test specimen has been developed for micro-scale tensile strength measurements, allowing direct assessment of surface effects on strength. Specimens were formed by deep reactive ion etching, tested with instrumented indentation, and test results

GRADED STRUCTURES FOR ALL-CERAMIC RESTORATIONS

May 17, 2010
Author(s)
Yu Zhang, H Chai, Brian R. Lawn
One failure mode of all-ceramic crown restorations is radial cracking at the cementation surface, from occlusally-induced flexure of the stiffer crown layer on the softer dentin underlayer. We hypothesize that such failure may be substantially mitigated by
Displaying 1701 - 1725 of 2146