Multiscale simulations of atomistic/continuum coupling in computational materials science, where the scale expands from macro-/micro- to nanoscale, has become a hot research topic. These small units, usually nanostructures, are commonly anisotropic. The development of molecular modeling tools to describe and predict the mechanical properties of structures reveals an undeniable practical importance. Typical anisotropic structures (e.g. cubic, hexagonal, monoclinic) using DFT, MD, and atomic finite element methods are especially interesting, according to the modeling requirement of upscaling structures. It therefore connects nanoscale modeling and continuous patterns of deformation behavior by identifying relevant parameters from smaller to larger scales. These methodologies have the prospect of significant applications. I would like to recommend this book to both beginners and experienced researchers.

Nanostructures are emerging as novel materials with revolutionary application in electronics, nuclear reactors, structures, aerospace, and energy. Nanocrystalline structures owe their outstanding mechanical properties to their nanoscale grain size and high density of crystalline interfaces called grain boundaries. Recently, nanotwinned structures, containing special grain boundaries called twin boundaries, have become quite attractive as optimal motifs for strength, ductility, and grain stability in metals. This dissertation presents our atomistic study of the role of these grain boundaries and twin boundaries in governing the mechanical response of nanostructures by way of different atomistic simulation methods. Nanopillar compression is first used to investigate the interplay between size effects associated with the twin spacing and the finite size of nanopillars by molecular dynamics. Simulations reveal that there exists an optimal aspect ratio for which the yield strength of twinned nanopillars is higher than even single crystal nanopillars. In addition, it is observed that twin boundaries facilitate dislocation-starvation as defects glide along twin boundaries and are annihilated at the free surface. Approaching experimentally-relevant strain rates has been a long-standing bottleneck for molecular dynamics. In this study, shearing of a nanopillar with a grain boundary is used as a paradigmatic problem to investigate the rate dependence of grain boundary sliding in nanostructures. A combination of time-scaling approaches is used including the recently developed autonomous basin climbing method, the nudged elastic band method, and kinetic Monte Carlo, to access strain rates ranging from 0.5s-1 to 107s-1. Although grain boundary sliding is the primary mechanism observed in all simulations, at lower strain rate, sliding initiates at significantly lower stress and occurs on the time-scale of seconds which is beyond the reach of conventional molecular dynamics. Finally the time scaling approach is used to investigate the diffusion of radiation-induced point defects through nanotwinned metals. The simulations reveal that dumbbell interstitials can cross coherent twin boundaries in three low energy barrier steps which can occur even at room temperature. Furthermore, the method shows that Frenkel pairs have greater probability to recombine in the vicinity of coherent twin boundaries which is consistent with observations reported by other computational studies.

Atomistic simulations provide a necessary lens through which to characterize nanoscale phenomena. This dissertation begins with a description of molecular models and the development of aninteratomic potential for benzene which incorporates atomic-level anisotropy. This model was made possible for bulk benzene systems through the implementation of a software plugin for the OpenMM simulation package, which enables custom force expressions with atomic-level anisotropy. This initial discourse on force field development summarizes the types of interatomic potentials used in simulations and avenues for improved accuracy. This knowledge of fundamental force field development is transferrable to developing approaches in modeling inorganic crystallization. Solid-phase epitaxy (SPE) is a crystal growth technique which employs low-temperature annealing conditions to exact kinetic control over the final grown structure. In this dissertation, classical simulations are used to rigorously define the mechanism of epitaxial growth in strontium titanate over patterned substrates. Modeling SPE is challenging from a simulation perspective because long timescales at experimental growth temperature exceed computational feasibility. The enhanced sampling method, metadynamics, is presented here as a viable alternative for probing crystallization mechanisms in super-cooled and viscous systems, for which diffusion is limited. Gaining mechanistic information from metadynamics is dependent on the "goodness" of reaction coordinate. Here, an XRD-based coordinate is used to distinguish not only between the amorphous and crystal structures but also among metastable crystal polymorphs. This dissertation summarizes work which encompasses research spanning molecular models and inorganic crystallization with added commentary on outreach and communication.

The present collection of articles focuses on the mechanical strength properties at micro- and nanoscale dimensions of body-centered cubic, face-centered cubic and hexagonal close-packed crystal structures. The advent of micro-pillar test specimens is shown to provide a new dimensional scale for the investigation of crystal deformation properties. The ultra-small dimensional scale at which these properties are measured is shown to approach the atomic-scale level at which model dislocation mechanics descriptions of crystal slip and deformation twinning behaviors are proposed to be operative, including the achievement of atomic force microscopic measurements of dislocation pile-up interactions with crystal grain boundaries or with hard surface coatings. A special advantage of engineering designs made at such small crystal and polycrystalline dimensions is the achievement of an approximate order-of-magnitude increase in mechanical strength levels. Reasonable extrapolation of macro-scale continuum mechanics descriptions of crystal strength properties at micro- to nano-indentation hardness measurements are demonstrated, in addition to reports on persistent slip band observations and fatigue cracking behaviors. High-entropy alloy, superalloy and energetic crystal properties are reported along with descriptions of deformation rate sensitivities, grain boundary structures, nano-cutting, void nucleation/growth micromechanics and micro-composite electrical properties.

Presents the most up-to-date information on the state of Materials Fabrication, Properties, Characterization, and Modeling. It's a great mix of practical applied technology and hard science, which is of invaluable benefit to the global industry.

This book shows how nanofabrication techniques and nanomaterials can be used to customize packaging for nano devices with applications to electronics, photonics, biological and biomedical research and products. It covers topics such as bio sensing electronics, bio device packaging, MEMS for bio devices and much more, including: Offers a comprehensive overview of nano and bio packaging and their materials based on their chemical and physical sciences and mechanical, electrical and material engineering perspectives; Discusses nano materials as power energy sources, computational analyses of nano materials including molecular dynamic (MD) simulations and DFT calculations; Analyzes nanotubes, superhydrophobic self-clean Lotus surfaces; Covers nano chemistry for bio sensor/bio material device packaging. This second edition includes new chapters on soft materials-enabled packaging for stretchable and wearable electronics, state of the art miniaturization for active implantable medical devices, recent LED packaging and progress, nanomaterials for recent energy storage devices such as lithium ion batteries and supercapacitors and their packaging. Nano- Bio- Electronic, Photonic and MEMS Packaging is the ideal book for all biomedical engineers, industrial electronics packaging engineers, and those engaged in bio nanotechnology applications research.

Liquid crystals, polymers and polymer liquid crystals are soft condensed matter systems of major technological and scientific interest. An understanding of the macroscopic properties of these complex systems and of their many and interesting peculiarities at the molecular level can nowadays only be attained using computer simulations and statistical mechanical theories. Both in the Liquid Crystal and Polymer fields a considerable amount of simulation work has been done in the last few years with various classes of models at different special resolutions, ranging from atomistic to molecular and coarse-grained lattice models. Each of the two fields has developed its own set of tools and specialized procedures and the book aims to provide a state of the art review of the computer simulation studies of polymers and liquid crystals. This is of great importance in view of a potential cross-fertilization between these connected areas which is particularly apparent for a number of experimental systems like, e.g. polymer liquid crystals and anisotropic gels where the different fields necessarily merge. An effort has been made to assess the possibilities of a coherent description of the themes that have developed independently, and to compare and extend the theoretical and computational techniques put forward in the different areas.