Search

In the present work, the molecular dynamics study method has been utilised to investigate the effects of pressure on the volatilisation of pure Bi nanoparticles and Bi–Fe core–shell nanoparticles during continuous heating. Computational total energy curves between 300 and 2000 K are used to explore the structural changes of nanoparticles under different pressures. On the other hand, the radial distribution function is examined to determine the structural evolution of a system. The calculated root mean square displacement curves under pressures of 0–5 GPa between 300 and 2000 K are employed to explore the diffusion of Bi element and the calculated volatilisation rate of Bi element is used to quantitatively obtain the volatilisation characteristics. The volatilisation patterns of pure Bi nanoparticles and Bi–Fe core–shell nanoparticles are different under different temperatures and pressures. The results show that the volatilisation of Bi element is increasing during the heating from 300 to 2000 K, and the volatilisation decreases with the increase of pressure. Furthermore, the Fe shell can effectively decrease the volatilisation of the Bi element. [ABSTRACT FROM AUTHOR]

Reinforcing cementitious composites with nanomaterials is an effective way to reduce porosity and enhance thermal conductivity (TC). In this study, the TCs of cementitious composites were predicted using an innovative theoretical framework combining numerical simulations (molecular dynamics) and theoretical analyses (homogenization theory and effective medium theory). The effects of thermal and geometric parameters upon the TC were investigated. Graphene and graphene oxide were selected as representative nanomaterials to estimate the TC, owing to excellent heat transfer property. According to the theoretical framework, two evaluation indicators were firstly provided to evaluate the reinforcing effect of nanomaterials upon the TC. This study provides theoretical support and specifications for practical experiments and engineering applications. [ABSTRACT FROM AUTHOR]