Thermal rectification in mass-graded next-nearest-neighbor Fermi-Pasta-Ulam lattices

We study the thermal rectification efficiency, i.e., quantification of asymmetric heat flow, of a one-dimensional mass-graded anharmonic oscillator Fermi-Pasta-Ulam lattice both with nearest-neighbor (NN) and next-nearestneighbor (NNN) interactions. The system presents a maximum rectification efficiency for a very precise value of the parameter that controls the coupling strength of the NNN interactions, which also optimizes the rectification figure when its dependence on mass asymmetry and temperature differences is considered. The origin of the enhanced rectification is the asymmetric local heat flow response as the heat reservoirs are swapped when a finely tuned NNN contribution is taken into account. A simple theoretical analysis gives an estimate of the optimal NNN coupling in excellent agreement with our simulation results.J.M.L.thanks Direccion General de Investigación Científica y Técnica, MINECO (Spain) for financial support through the project No. FIS2014-59462-P

Recent advances and perspectives on starch nanocomposites for packaging applications

Starch nanocomposites are popular and abundant materials in packaging sectors. The aim of this work is to review some of the most popular starch nanocomposite systems that have been used nowadays. Due to a wide range of applicable reinforcements, nanocomposite systems are investigated based on nanofiller type such as nanoclays, polysaccharides and carbonaceous nanofillers. Furthermore, the structures of starch and material preparation methods for their nanocomposites are also mentioned in this review. It is clearly presented that mechanical, thermal and barrier properties of plasticised starch can be improved with well-dispersed nanofillers in starch nanocomposites

Thermal resonance and energy transport in a biharmonically driven Frenkel–Kontorova lattice

In this work, we study the heat conduction properties of a one-dimensional Frenkel–Kontorova lattice driven by an external, time-periodic biharmonic force applied locally at one boundary and in contact with two heat reservoirs operating at different temperature by means of molecular dynamics simulations. In the single-frequency externally driven case already studied it was observed that there is a value of the driving frequency at which the heat flux takes its maximum value, a phenomenon termed as thermal resonance. It was also determined that it is possible to direct the heat flow against the imposed temperature bias by adjusting the frequency of the single harmonic driving force. With the implementation of the biharmonic forcing we have explored the temperature range at which thermal resonance effect is present. Furthermore, we have determined that by changing the relative amplitude of both harmonic components as well as the frequency of the second, taken always as a multiple, not necessarily integer, of the first one, we can adjust the frequency at which the studied effect is present in the proposed model