A numerical method to identify thermal conductivity from time history of one-dimensional temperature variations in thermal unsteady-state is proposed. The numerical method considers the change of specific heat and thermal conductivity with respect to temperature. Fire test of reinforced concrete (RC) columns was conducted using a standard fire to obtain time history of temperature variations in...

A model of gas–surface reactivity is developed based on the ideas that ~a! adsorbate chemistry is a local phenomenon, ~b! the active system energy of an adsorbed molecule and a few immediately adjacent surface atoms suffices to fix microcanonical rate constants for surface kinetic processes such as desorption and dissociation, and ~c! energy exchange between the local adsorbate–surface complexe...

In this paper natural convection heat transfer within a two-dimensional, horizontal, concentric cam shape cylinders that is partially filled with a fluid saturated porous medium has been investigated. both cylinder are kept at constant and uniform temperatures with the outer cylinder being subjected relatively lower than the inner one. In addition the forchheimer and brinkman effect are taken i...

In the present study, analytical solutions for thermally developing flows in porous media under local thermal non-equilibrium (LTNE) condition are derived for different fundamental models. The analytical solutions are validated by comparison with the numerical results. Based on the analytical solutions, the local Nusselt number is obtained, and the dimensionless thermal entry length nc is predi...

Thermodynamics relies on the possibility to describe systems composed of a large number of constituents in terms of few macroscopic variables. Its foundations are rooted into the paradigm of statistical mechanics, where thermal properties originate from averaging procedures which smoothen out local details. While undoubtedly successful, elegant and formally correct, this approach carries over a...

We show that the two-point cross-correlation of potential-field recordings is proportional to the Green’s function between the two points. This holds under the condition that spatially and temporally uncorrelated quasi-static noise sources exist throughout the volume. Natural fluctuations, such as thermal noise, may occur that satisfy the necessary conditions. When these fluctuations are random...

We consider a model of galaxy clusters in which the hot gas is in hydrostatic equilibrium and maintains energy balance between radiative cooling and heating by thermal conduction. We analyze the thermal stability of the gas using a Lagrangian perturbation analysis. For thermal conductivity at the level of ∼ 20 − 40% of Spitzer conductivity, consistent with previous estimates for cluster gas, we...