Abstract--A procedure is presented to determine the moisture diffusivity for drying from measured moisture concentratio~a profiles. From error analysis it is shown that the applied space grid for scanning and the one-dimensional resolution of the NMR (nuclear magnetic resonance) method used for the measurements had a minor influence on the accuracy of the determination of the moisture diffusivi...

On equilibrium vicinal surfaces with mass transport dominated by terrace-diffusion (TD), there can be crossover from TD to diffusion step-to-step (DSS) behavior for fluctuation wavelength k large compared to the step separation ‘. We show that the temporal correlation function for 180 -out-of-phase fluctuations can be written as a function of a single dimensionless variable proportional to time...

The electrical impedance behavior of gellan gum (GG), GG-carbon nanotube, and GG-carbon nanofiber hydrogel composites is reported. It is demonstrated that the impedance behavior of these gels can be modeled using a Warburg element in series with a resistor. Sonolysis (required to disperse the carbon fillers) does not affect GG hydrogel electrical conductivity (1.2 ± 0.1 mS/cm), but has a detrim...

In this study, we examined the intestinal uptake of thiamin (vitamin B(1)), riboflavin (vitamin B(2)) and pyridoxine (vitamin B(6)) administered at high concentration using intestinal epithelial Caco-2 cells as an in vitro model of drugs and food absorption. The effect of vitamin concentration, culture age, transport direction and incubation temperature on vitamin transport was determined. The ...

Failure to grow thick (3D) implantable bone tissue is partly due to the lack of tissue vascularisation resulting from a fall in nutrient supply to the cells as the distance between the cells and nutrient sources increases. Previous attempts that used porous scaffold without hollow fibre (HF) produced tissues of less than 0.5mm thickness which are of limited clinical use. Recent studies suggest ...

The air-gap field-effect technique enabled realization of the intrinsic (not limited by static disorder) polaronic transport on the surface of rubrene (C42H28) crystals over a wide temperature range. The signatures of this intrinsic transport are the anisotropy of the carrier mobility, mu, and the growth of mu with cooling. Anisotropy of mu vanishes in the activation regime at low temperatures,...

Spin-coherent quantum transport in carbon nanotube magnetic tunnel junctions is investigated theoretically. A spin-valve effect is found for metallic, armchair tubes, with a magnetoconductance ratio ranging up to 20%. Because of the finite length of the nanotube junctions, transport is dominated by resonant transmission. The magnetic tunnel junctions are found to have distinctly different trans...

Charge transport in a porphyrin with four identical pyridyl substituents, 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine (TPyP), was investigated using the scanning tunneling microscopy break junction method. To determine the dominant pathway, we studied two structurally similar porphyrins, o-DPyP and p-DPyP. Our experiments reveal that charge transport through TPyP in a break junction configurat...

Until five years ago the scene of public transport in Brazilian cities was dominated by privately operated buses under local protective regulation. From 1996 on, however, this scene begun to change by the emergence of vans operators who challenged bus cartels and the barriers to entry imposed by public authorities. In this paper, a general overview of the presence of vans in Brazilian local pub...