Morthemer Ortiz

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We study the problem of atomic scale fracture using the recently developed quasicontinuum method in which there is a systematic thinning of the atomic-level degrees of freedom in regions where they are not needed. Fracture is considered in two distinct settings. First, a study is made of cracks in single crystals, and second, we consider a crack advancing(More)
Lima bean is a species cultivated broadly in the Americas and has been cultivated in the Caribbean for at least 500 years. In order to determine the genetic structure and diversity of Lima bean from the Caribbean, 50 landraces from Haiti, the Dominican Republic and Puerto Rico were collected and analyzed using 24 SSR markers. All landraces in this Caribbean(More)
We present a streamlined limiting case of the theory of Ortiz & Repetto for crystals with microstructure in which the crystals are assumed to exhibit in¯nitely strong latent hardening. We take this property to signify that the crystal must necessarily deform in single slip at all material points. This requirement introduces a non-convex constraint that(More)
Complex lattice Quasicontinuum theory is applied to simulations of phenomena in tetragonal phase BaTiO/sub 3/. Quasicontinuum theory is a multiscale theory, which bridges a unified continuum and atomistic description of materials at the same time. Handling millions of atoms simultaneously, Quasicontinuum derives the description of the materials directly(More)
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