The advent of nanotechnologyhas necessitated a better understanding of how the material microstructurechanges at the atomic level would affect the macroscopic properties thatcontrol the performance. Such a challenge has uncovered many phenomenathat were not previously understood and taken for granted. Among themare the basic foundation of dislocation theories which are now known tobe inadequate. Simplifying assumptions invoked at the macroscale may notbe applicable at micro- and/or nanoscale. There are implications ofscaling hierarchy associated with inhomogeneity and nonequilibrium ofphysical systems. What is taken to be homogeneous and in equilibrium atthe macroscale may not be so when the physical size of the material isreduced to microns. These foundamental issues cannot be dispensed atwill for the sake of convenience because they might alter the outcome ofpredictions. Even more unsatisfying is the lack of consistency inmodeling physical systems. This could be translated to the inability foridentifying the relevant manufacturing parameters and rendering the endproduct unpractical because of high cost. Advanced composite andceramic materials are cases in point.Discussed are potential pitfalls for applying models at both the atomicand continuum levels. No encouragement is made to unravel the truth ofnature. Let it be particulates, a smooth continuum or combinationof both. The present trend of development in scaling tends to seekdifferent characteristic lengths of material microstructure with orwithout the influence of time effects. Much will be learned fromatomistic simulation models to show how results could differ asboundary conditions and scales are changed. Quantum mechanics,continuum and cosmological models provide evidence that no generalapproach is in sight. Of immediate interest is perhaps theestablishment of greater precision in terminology so as to bettercommunicate results involving multiscale physical events.
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