Using a semiempirical tight-binding approach modified through introduction of a deformation potential, we have calculated the effects of uniaxial stress on the electronic density of states of carbon tubules. For zigzag tubules (n,0) the gap varies linearly with stress and independently of diameter: |${\mathrm{dE}}_{\mathrm{gap}}$/dσ|=10.7 meV/GPa for |σ| ≺10 GPa, and a semiconductor to metal transition is predicted. The behavior is strongly dependent on whether n=3q,3q-1,3q+1. The armchair tubules remain metallic under all conditions studied.

The dynamic viscosity and rheological properties of two different non-aqueous graphene nano-plates-based nanofluids are experimentally investigated in this paper, focusing on the effects of solid volume fraction and shear rate. For each nanofluid, four solid volume fractions have been considered ranging from 0.1% to 1%. The rheological characterization of the suspensions was performed at 20 ${}^{\circ }$C, with shear rates ranging from ${10}^{-1}{\mathrm{s}}^{-1}$ to ${10}^3{\mathrm{s}}^{-1}$, using a cone-plate rheometer. The Carreau–Yasuda model has been successfully applied to fit most of the rheological measurements. Although it is very common to observe an increase of the viscosity with the solid volume fraction, we still found here that the addition of nanoparticles produces lubrication effects in some cases. Such a result could be very helpful in the domain of heat extraction applications. The dependence of dynamic viscosity with graphene volume fraction was analyzed using the model of Vallejo et al.

We have developed hot-wire anemometry applying the 3ω method. The approach is based on the same heat transfer process as traditional anemometry, but substituting the constant current by a sinusoidal current and using synchronous detection to measure the conductive-convective exchange coefficient and the gas flow rate. Our theoretical model is tested with air flow at 300 K under atmospheric pressure: The experimental results are in agreement with the numerical simulation, justifying the technical choices in the 3ω method and the approximations made. The effectiveness of the 3ω method for measuring the flow rate and the conductive-convective exchange coefficient between the hot wire and flowing gas is discussed.