This paper discusses the thermal conduction anisotropy in polymers by reviewing currently available theories and experimental methods for studying oriented polymers. The anisotropic thermal conductivity and diffusivity of oriented polymers originate from the difference between the thermal energy transport mechanisms parallel and perpendicular to their molecules. Recent progress in the developme...

We study the nonequilibrium state of heat conduction in a one-dimensional system of hard point particles of unequal masses interacting through elastic collisions. A BBGKY-type formulation is presented and some exact results are obtained from it. Extensive numerical simulations for the two-mass problem indicate that, even for arbitrarily small mass differences, a nontrivial steady state is obtai...

The accurate assessment of the thermal conductivity of concretes is an important part of building design in terms of thermal efficiency and thermal performance of materials at various temperatures. We present an experimental assessment of the thermal conductivity of five thermally insulated concrete specimens made using lightweight aggregates and glass bubbles in place of normal aggregates. Fou...

Observations of the hot gas, which is surrounding Sgr A* and a few other nearby galactic nuclei, imply that mean free paths of electron and proton are comparable to gas capture radius. So, hot accretion flows likely proceed under week collision conditions. As a result thermal conduction by ions has a considerable contribution in transfer of the realized heat in accretion mechanisms. We study a ...

Recently, Medvedev & Narayan (2001) discovered a new type of accretion flow, a hot settling flow around a rapidly rotating neutron star. The flow is cooling-dominated and energetically similar to the Shapiro, Lightman, & Eardley (1976, SLE) solution. Since the SLE solution is known to be thermally unstable, one might suspect that the new solution would also be unstable. However, due to the very...

Based on the recently introduced fractional Taylor’s formula, a fractional heat conduction constitutive equation is formulated by expanding the single-phase lag model using the fractional Taylor’s formula. Combining with the energy balance equation, the derived fractional heat conduction equation has been shown to be capable of modeling diffusion-to-Thermal wave behavior of heat propagation by ...

The effect of thermal radiation within a porous medium while incorporating local thermal nonequilibrium (LTNE) is investigated in this work, with specific application to solar air receivers. It is shown that the radiation effect is significant. The temperature distributions for both solid and fluid phases are affected by conduction-radiation parameter N, the ratio of solid to fluid phase conduc...

We present the dynamics in thermally bistable medium by using onedimensional numerical calculations with cooling, heating, (realistic) thermal conduction, and physical viscosity. We set up a two-phase medium from thermally unstable one-phase medium and follow the long-term evolution of the medium. We focus on the spatial resolution because we have to resolve Field length λF that is the critical...

Why heat and mass transfer ................................................................................................................................1 Fundamentals of heat transfer (what is it) ..........................................................................................................2 Thermodynamics of heat transfer ............................................................