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Mehrdad Mozaffarian,Saeid Atashrouz,Gholamreza Pazuki 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.9
The viscosity and rheological behavior of an ethylene glycol-water mixture based Fe3O4 nanofluid have been experimentally investigated. The nanofluids for this study were prepared by a two-step method in which Fe3O4 nanoparticles were added to a base fluid mixture consisting of 60% (w/w) ethylene glycol and 40% (w/w) water. The measurements were conducted at temperatures ranging from 288.15 to 343.15 K, and at nanoparticle volume fractions ranging from 0.0022 to 0.0055. Furthermore, the dependency of viscosity of nanofluids on shear rate was examined. The results indicate that increasing the shear rate leads to a reduction in the viscosity (shear thinning behavior). Finally, the obtained experimental data was correlated by both a thermodynamic model and a hybrid GMDH-type polynomial neural network, where the mean absolute relative deviation (MARD) of these models was calculated as 3.64% and 3.88%, respectively.
Zakaria Loloie,Mehrdad Mozaffarian,Mansooreh Soleimani,Neda Asassian 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.2
This research demonstrates the production of activated carbon from scrap tires via physical activation with carbon dioxide. A newly constructed apparatus was utilized for uninterrupted carbonization and activation processes. Taguchi experimental design (L16) was applied to conduct the experiments at different levels by altering six operating parameters. Carbonization temperature (550-700 oC), activation temperature (800-950 oC), process duration (30-120 min), CO2 flow rate (400 and 600 cc/min) and heating rate (5 and 10 oC/min) were the variables examined in this study. The effect of parameters on the specific surface area (SSA) of activated carbon was studied, and the influential parameters were identified employing analysis of variance (ANOVA). The optimum conditions for maximum SSA were: carbonization temperature=650 oC, carbonization time=60min, heating rate=5 oC/min, activation temperature= 900 oC, activation time=60min and CO2 flow rate=400 cc/min. The most effective parameter was activation temperature with an estimated impact of 49%. The activated carbon produced under optimum conditions was characterized by pore and surface structure analysis, iodine adsorption test, ash content, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The process yield for optimized activated carbon was 13.2% with the following properties: specific surface area=437m2/g, total pore volume=0.353 cc/g, iodine number=404.7mg/g and ash content=13.9% along with an amorphous structure and a lot of oxygen functional groups. These properties are comparable to those of commercial activated carbons.