In the case of straight flow but with hydraulic conductivity varying in a transverse direction, the distribution of hydraulic conductivity has been determined for which the breakthrough curve due to convection only will have the same analytical form as the onedimensional convection/dispersion equation solution at the outlet end of a porous medium. That distribution is found exactly and it is ve...

We analyze spin transport in insulating antiferromagnets described by the XXZ Heisenberg model in two and three dimensions. Spin currents can be generated by a magnetic-field gradient or, in systems with spin-orbit coupling, perpendicular to a time-dependent electric field. The Kubo formula for the longitudinal spin conductivity is derived analogously to the Kubo formula for the optical conduct...

We have simulated the heat conduction characteristics of finite length single walled carbon nanotubes (SWNTs) with the molecular dynamics method [1-3] with Tersoff-Brenner bond order potential. Temperature at each end of a SWNT was controlled by the phantom technique, and the thermal conductivity was calculated with Fourier’s law from the measured temperature gradient and the energy budgets in ...

(1) Ideal general relativistic MHD (ideal GRMHD) simulation: Jet formation by magnetic bridges between the ergosphere and disk around a rapidly black hole: Anti-parallel magnetic field ⇒ Magnetic reconnection (2) GRMHD with finite conductivity (σGRMHD): Numerical method and simple tests

We exhibit a target signature obtainable from the electromagnetic far field pattern at fixed frequency that allows one to distinguish a perfect conductor from an anisotropic medium of finite conductivity. © 2004 IMACS. Published by Elsevier B.V. All rights reserved.

In a Monte Carlo study the conductivity of two-dimensional random stick systems is investigated from the percolation threshold up to ten times the percolation threshold density. We propose a model explicitly depending on the stick density and junction-to-stick conductance ratio. The model describes the transition from the conductivity determined by the structure of a percolating cluster to the ...

On the Parametrization of Ill-posed Inverse Problems Arising from Elliptic Partial Differential Equations by Fernando Guevara Vasquez Electric impedance tomography (EIT) consists in finding the conductivity inside a body from electrical measurements taken at its surface. This is a severely ill-posed problem: any numerical inversion scheme requires some form of regularization. We present inversi...

[1] We studied the thermomechanical effects on surface heat flow near major faults from positive feedback between temperature-dependent thermal conductivity k(T)∝ (1/T) and frictional heating in a crust-lithosphere system using finite element simulations. Variable conductivity and frictional heating cause a drastic reduction in the thermal conductivity, and these changes can impact the heat flu...

In this paper, finite element method is used to obtain thermal conductivity coefficients of single-walled carbon nanotube reinforced polypropylene. For this purpose, the two-dimensional representative volume elements are modeled. The effect of different parameters such as nanotube dispersion pattern, nanotube volume percentage in polymer matrix, interphase thickness between nanotube and surroun...