Electrokinetic flows are generally analyzed, assuming isothermal conditions even though such situations are hard to be achieved in practice. In this paper, the flow of a symmetric electrolyte in a charged nanochannel subjected to an axial temperature gradient is investigated using molecular dynamics simulations. We analyze the relative contribution of the Soret effect, the thermoelectric effect, and the double layer potential in the electrical double layer for various surface charges and temperature gradients. We find the flow driven by thermal gradient is analogous to electroosmotic flow. The thermophoretic motion of the electrolyte is significant for negative surface charge than the positive surface charge. The vibrational spectrum of graphene is calculated to delineate the effect of the surface charge polarity on the observed thermophoretic motion of the electrolyte. A unique structure of interfacial water layer is observed for the positive and negative surface charges. We attribute the presence of these structures to the differences in water-carbon interactions existing for various surface charge polarity. For an applied thermal gradient in the range 2.6 K nm−1 to 8 K nm−1, we observe a continuous net flow with average velocities reaching up to 9.4 m s−1 inside the channel for a negative surface charge of −0.101 C m−2. The results indicate that in a charged graphene-based nanochannel, temperature gradients can be employed to induce streaming current, depending on the relative influence of the Soret effect and the double layer potential.

Thermal transport in graphene is strongly influenced by strain. We investigate the influence of biaxial tensile strain on the thermal conductivity of zigzag and armchair graphene (AG and ZG) using non-equilibrium molecular dynamics simulations (NEMD). We observe that the thermal conductivity is significantly reduced under strain with a maximum reduction obtained at equi-biaxial strain. It is interesting to note that the high lateral to longitudinal strain ratios reduce the negative impact of strain on the thermal conductivity of AG and ZG. The in-plane acoustic modes are found to be the major heat carriers in unstrained graphene but are severely softened due to strain, and hence, their contribution to the conductivity drops down significantly. Strain alleviates the out-of-plane fluctuations in graphene and the group velocity of the out-of-plane acoustic mode (ZA) increases due to the linearisation of its dispersion relation. These factors result in the dominance of ZA mode in the thermal transport of strained graphene. Significant increase in the size dependence of the thermal conductivity of strained graphene is observed, which is attributed to the long-wavelength ZA phonons. The discrepancies between the results of BTE studies and NEMD are also discussed. This study suggests that biaxial strain can be an effective method to tune the thermal transport in graphene. Our findings can lead to better phonon engineering of graphene for various nanoscale applications.

Petroleum products are now current consumption rate it will be depleting in upcoming decades. Ethanol usage is one of the transport sectors can fulfill the requirement and contribute to mitigating the greenhouse gas emissions of the vehicles. In order to expand the SI engine this can work on 100% ethanol or adding ethanol in petrol and use the blends of that. The intention of this work is to study the thermal characteristics of Gasoline and its E5, E10, E15 ethanol blends. All thermograms of heat flow exhibited at a 350C-2800C temperature range at heating rate of 100C/min in atmospheric air as medium. Transport properties like Thermal conductivity, Specific Heat capacity and Thermal diffusivity are studied using TPS500(s). This study concludes that ethanol blending is the lowest exhaust emissions with considerable improvement in the performance of the Spark Ignition (SI) engine and promising, Ethanol as a future fuel which can be fortunately replace petrol and its depletion problem.

Thermal transport in 2-D (Dimensional) structures is highly susceptible to external perturbations such as strain, owing to their high surface-to-volume ratio. In this study, we investigate the influence of strain...

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