We examine the temperature dependence of thermal conductivity of one dimensional nonlinear (anharmonic) lattices with and without on-site potential. It is found from computer simulation that the heat conductivity depends on temperature via the strength of nonlinearity. Based on this correlation, we make a conjecture in the effective phonon theory that the meanfree-path of the effective phonon i...

Vacuum insulation panel (VIP) is a promising thermal insulator for buildings, refrigerator, LNG carrier and so on. In general, it has the thermal conductivity of 2~4 mW/m·K. However, this thermal conductivity is that measured at the center of VIP. The total effective thermal conductivity of VIP is larger than this value due to the edge conduction through the envelope. In this paper, the edge co...

One of the most important physical factors related to the thermal conductivity of composites filled with graphene nanoplatelets (GNPs) is the dimensions of the GNPs, that is, their lateral size and thickness. In this study, we reveal the relationship between the thermal conductivity of polymer composites and the realistic size of GNP fillers within the polymer composites (measured using three-d...

PURPOSE Electroencephalogram (EEG) source analysis is a noninvasive technique used in the presurgical of epilepsy. In this study, the dipole location and orientation errors due to skull conductivity perturbations were investigated in two groups of three-dimensional head models: A spherical head model and a realistic head model. METHODS In each group, the head model had a brain-to-skull conduc...

In light of its frequency-dependent penetration depth, the measurement of eddy current conductivity has been suggested as a possible means to allow the nondestructive evaluation of subsurface residual stresses in shot-peened specimens. This technique is based on the socalled electro-elastic effect, i.e. the stress-dependence of the electrical conductivity. Unfortunately, the relatively small ch...

Magnetic resonance electrical impedance tomography (MREIT) is an emerging method to visualize electrical conductivity and/or current density images at low frequencies (below 1 KHz). Injecting currents into an imaging object, one component of the induced magnetic flux density is acquired using an MRI scanner for isotropic conductivity image reconstructions. Diffusion tensor MRI (DT-MRI) measures...

We present an eecient numerical method for solving stochastic porous media ow problems. Single-phase ow with a random conductivity eld is considered in a standard rst-order perturbation expansion framework. The numerical scheme, based on nite element techniques , is computationally more eecient than traditional approaches, because one can work with a much coarser nite element mesh. This is achi...

We use Quantum Monte Carlo to evaluate the conductivity σ of the 2–dimensional disordered boson Hubbard model at the superfluid-bose glass phase boundary. At the critical point for particle density ρ = 0.5, we find σ c = (0.45 + 0.07)σ Q , where σ Q = e 2 * /h from a finite size scaling analysis of the superfluid density. We obtain σ c = (0.47 + 0.08)σ Q from a direct calculation of the current...

The main point of this paper is to propose a non-local three-dimensional hydraulic conductivity full tensor upscaling algorithm and code. The algorithm is capable of transforming very refined cell conductivity models into coarse block conductivity models for quick and accurate solution of the groundwater flow equation. Flow rate and hydraulic head gradient are the variables used to relate the o...

We report on a zero magnetic field transport study of a two-dimensional, variable-density, hole system in GaAs. As the density is varied we observe, for the first time in GaAs-based materials, a crossover from an insulating behavior at low density, to a metalliclike behavior at high density, where the metallic behavior is characterized by a large drop in the resistivity as the temperature is lo...