The stationary hemispherical electrode under a submerged impinging jet is suggested as an experimental system that is amenable to in situ observation and has a uniform current distribution below the mass-transfer-limited value. The present work provides solutions for the steady-state boundary-layer hydrodynamics and convective diffusion. The observation of a boundary layer separation in the pre...

This paper presents a mathematical model of carbon nanotubes-based mediatorless biosensor. The developed model is based on nonlinear non-stationary reaction-diffusion equations. The model involves four layers (compartments): a layer of enzyme solution entrapped on a terylene membrane, a layer of the single walled carbon nanotubes deposited on a perforated membrane, and an outer diffusion layer....

In polymer electrolyte membrane fuel cells, power losses associated with slow reaction kinetics and mass-transport limits can be strongly nfluenced by convective flow characteristics. Specifically, convection in the form of channel bypass may be utilized to simultaneously increase eactant concentration and reduce product concentration in the catalyst layer, thus reducing the activation and mass...

In ordinary polymer solar cells, the short exciton diffusion length causes increasing probability of electron–hole recombination as the active layer thickness exceeds the diffusion length. Hence, the diffusion sets a thickness limitation of the active layer. ZnO nanorods have been used to provide an advantage of electronic path, making it possible to increase the effective thickness of the acti...

The redox switching kinetics, that is, charge transfer and transport in layer-by-layer-deposited electroactive polyelectrolyte multilayers is systematically studied with variable-scan-rate cyclic voltammetry. The experiments are performed with films finished in the redox polycation (an osmium pyridine-bipyridine derivatized polyallylamine, PAH-Os) and the polyanion (polyvinyl sulfonate, PVS), i...

The influence of surface characteristics on membrane process performance is considered significant and is not well understood. This work evaluated mass transfer processes by incorporating surface morphology into a diffusion-based model assuming MTCs are dependent on the thickness variation of the membrane's active layer. To mathematically create such a layer, Gaussian random vectors embedded in...

Observational evidence indicates that the bubble layer beneath the sea surface may show either an exponential or an inverse-square sound speed profile down to depths greater than 10 m. An exponential profile is consistent with a model of gas transport in which the downwardflux is due to turbulent diffusion and the d@usion coeficient is independent of depth. In this paper, a theoretical model is...

For an optimal functionality and a high durability of the planned SIS18 beam loss collimators a low ion-induced desorption yield of the collimator material is required. Gold coated copper was found to be the material of choice: copper has a high thermal conductivity, a high specific heat and can be produced with high purity for reasonable prizes. The gold layer prevents the copper from oxidatio...

the role of polymeric additives such as pvp and peg is studied with respect to the morphology of pes porous layer as a sublayer of nanofiltration composite membranes based on pes/pa. results show that by phase inversionprocess of quaternary systems comprised of four components of polymer/solvent/non-solvent/additive and the diffusion of intertwined polymers some changes occur in membrane morpho...

Background In recent years, diffusion tensor imaging (DTI) has emerged as a powerful noninvasive tool that infers the cardiac tissue organization through measuring water molecule motility.[1] Previous DTI studies [2] on normal hearts largely assumed that the measured diffusion magnitude along the 3 preferred directions and the measured degree of diffusion anisotropy remain the same over the end...