The spontaneous thermodynamically driven densification, the so-called physical aging, of glassy poly(mehtyl methacrylate) (PMMA) and its nanocomposites with silica has been described by means of the free volume holes diffusion model. This mechanism is able to account for the partial decoupling between physical aging and segmental dynamics of PMMA in nancomposites. The former has been found to b...

The internal structure of a molecule can be presented in terms of intra-molecular (i.e., inter atomic)and inter-molecular energies such as van der Waals, bond and bending, torsion, and inversion energy.In this study, changes in molecular energies of individual asphalt components are evaluated as afunction of physical aging factors. The factors for physical aging such as temperature and pressure...

BACKGROUND Self-perceptions of aging have been implicated as independent predictors of functional disability and mortality in older adults. In spite of this, research on self-perceptions of aging is limited. One reason for this is the absence of adequate measures. Specifically, there is a need to develop a measure that is theoretically-derived, has good psychometric properties, and is multidime...