Abstract When perpendicular diffusion is included into the focused transport equation, certain assumptions of coefficient (including well-known fieldline random walk limit) clearly lead to faster-than-light motion for relativistic particles, and that does not preserve causality in general. In this work we show discrepancy can be solved by including effect turbulence on particle drifts, especial...

Several preconditioners based on multigroup diffusion are developed for application to multiplying fixed-source transport problems using the discrete ordinates method. By starting from standard, one-group, diffusion synthetic acceleration (DSA), a multigroup diffusion preconditioner is constructed that shares the same fine mesh as the transport problem. As a cheaper but effective alternative, a...

We developed a novel method to accelerate diffusion spectrum imaging using compressed sensing. The method can be applied to either reduce acquisition time of diffusion spectrum imaging acquisition without losing critical information or to improve the resolution in diffusion space without increasing scan time. Unlike parallel imaging, compressed sensing can be applied to reconstruct a sub-Nyquis...

Diffusion behavior of water, diatomic oxygen, and a mixture of both into a poly(3hexylthiophene)[P3HT] melt were investigated using Molecular Dynamics Simulation. Once simulations were complete, the data was analyzed to determine the diffusion coefficient of those molecules in P3HT using Fick’s law. The diffusion coefficient values were then plotted as a function of concentration and temperatur...

in this paper, the effect of surface area of reaction layers in gas diffusion electrodes on oxygen reduction reaction was investigated. for this purpose, various amounts (0.1, 0.2, 0.3, 0.4, 0.5, 1, 1.5 and zero %wt of total loading of reaction layer) of single walled carbon nanotube (swcnt) were inserted in the reaction layer. the performance of gas diffusion electrodes for oxygen reduction re...

We study the coherence properties of optical vortices stored in atomic ensembles. In the presence of thermal diffusion, the topological nature of stored optical vortices is found not to guarantee slow decoherence. Instead the stored vortex state’s decoherence is surprisingly larger than the stored Gaussian mode. Furthermore, calculation of the coherence factor shows that the center of the store...

For many years, arterial thrombosis was considered a result of vascular injury combined with a “normal” response of circulating coagulation factors and formed elements. Indeed, the original articles describing tissue factor in atherosclerotic lesions1,2 implied that rupture or erosion of the plaque that results in contact of the circulating blood with plaque-bound tissue factor is sufficient to...

The objective of this study was to assess the adsorption potential of activated carbon (AC) asan adsorbent for the removal of Murexide (Mu) from aqueous solutions. The influence of variablesparameters including pH, amount of adsorbent, sieve size of adsorbent, temperature and contact timeon Mu removal was studied. Following optimization of variables, the relation between concentrations ofdye re...

I have measured acetylene diffusion through plant tissues including nodules from several species of legume-vetch, peas, soybeans, and Sesbania rostrata. The observed half-time for reequilibration of internal and external concentration is less than 1 minute for typical nodules. Inward diffusion of acetylene in air is rapid relative to the use of acetylene by nitrogenase so that diffusion of acet...

the goal is assessing the diffusion magnetic resonance imaging (dmri) method effi ciency in characterizing focal hepatic lesions (fhls). about 28-fhl patients were studied in radiology and clinical imaging department of our university hospital using 1.5 tesla mri system between january 2010 and june 2011. patients underwent hepatic mri consisting of dynamic t1- and t2-weighted imaging. the dmri...