Methods of Determination for Effective Diffusion Coefficient During Convective Drying of Clay Products
© 2012 Vasic et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Methods of Determination for Effective Diffusion Coefficient During Convective Drying of Clay Products
Calculation of Diffusion Coefficient of Drying Clay Ceramics using Firefly Algorithm and Studying Effects of Part Geometry
In this work, the effects of temperature, relative humidity, and air velocity on the effective difussion coefficient of four different clay ceramic samples are investigated. A full factorial design of experiments is performed on four cubic samples. In each trial, the mass and volume reductions are measured using an electronic balance and a vision system, respectively. The resulting data is recorded, and the drying curve is plotted. The effective diffusion coefficient of moisture is calculated using the newly developed firefly algorithm, in which the error defined as the difference between the analytical and experimental values is minimized. The statistical analysis and the analysis of variance (ANOVA) performed show that in the calculation of the effective diffusion coefficient, the velocity, temperature, and humidity are independent from one another. The greatest impact on the effective diffusion coefficient is related to the velocity, and this is followed by temperature and environmental humidity, respectively. Finally, using the drying parameters, the regression of the diffusion cofficient is obtaioned.
Neuronal uptake inhibitors, nisoxetine and fluoxetine on rat vascular contractions.
The importance of neuronal uptake processes in rat arteries and veins was compared using nisoxetine and fluoxetine, selective inhibitors for neuronal uptake of norepinephrine and serotonin, respectively. Nisoxetine (10(-7) - 10(-5) M) increased the sensitivity to exogenous norepinephrine in the portal and mesenteric veins (10-fold) and in the mesenteric artery (2.5-fold). Responses to field stimulation were also increased afternisoxetine in all three vessels. After nisoxetine, aortic responses to norepinephrine were unaltered and in all tissues, serotonin-induced contractions were reduced. Fluoxetine did not potentiate responses to norepinephrine or to field stimulation except in the mesenteric vein where sensitivity to norepinephrine was increased and the relaxation rate after field stimulation was prolonged. Although serotonin has been detected in blood vessels, fluoxetine did not increase vascular responses to serotonin. These studies suggest that rat mesenteric veins have a highly sensitive neuronal uptake mechanism of norepinephrine. Furthermore, these data provide indirect evidence against a functionally important serotonergic uptake process in rat blood vessels and suggest that neuronal uptake of serotonin does not exert a major role in terminating the vascular action of this biogenic amine.