Quasi-particle model for lattice QCD: quark-gluon plasma in heavy ion collisions

We propose a quasi-particle model to describe the lattice QCD equation of state for pure SU(3) gauge theory in its deconfined state, for $T \ge 1.5T_c$. The method involves mapping the interaction part of the equation of state to an effective fugacity of otherwise non-interacting quasi-gluons. We find that this mapping is exact. Using the quasi-gluon distribution function, we determine the energy density and the modified dispersion relation for the single particle energy, in which the trace anomaly is manifest. As an application, we first determine the Debye mass, and then the important transport parameters, {\it viz}, the shear viscosity, $\eta$ and the shear viscosity to entropy density ratio, $\eta/{\mathcal S}$. We find that both $\eta$ and $\eta/{\mathcal S}$ are sensitive to the interactions, and that the interactions significantly lower both $\eta$ and $\eta/\mathcal S$.Comment: 10 pages, 8 figures, epj class file, version accepted for publication in Euro. Phys.J

Monitoring Fluorescence Colors to Separately Identify Cracks and Healed Cracks in Microcapsule-containing Self-healing Coating

We developed a system involving an extrinsic self-healing coating to identify cracked and healed regions by their yellow fluorescence and blue fluorescence, respectively. This system consisted of a top coating, an epoxy matrix resin containing a yellow fluorescent dye, and a microcapsule. This microcapsule in turn consisted of a healing agent, a blue aggregated-induced emitting luminogen, and a photo-initiator, as well as poly(urea-formaldehyde) as a shell material. Embedding the self-healing coating with a 25 mass% of microcapsules yielded the most efficient fluorescence detection and healing of the damaged region. Scratched and healed regions were successfully detected using our system under UV irradiation as well as under a one sun condition similar to sunlight. The blue fluorescence of the healed region was easily seen from 2 m away