Current Issue : July - September Volume : 2014 Issue Number : 3 Articles : 6 Articles
Nanofluids have evoked immense interest from researchers all around the globe due to their numerous potential benefits and\napplications in important fields such as cooling electronic parts, cooling car engines and nuclear reactors. An analytical study\nof fluid flow of in-tube stratified regime of two-phase nanofluid has been carried out for CuO, Al2O2, TiO3, and Au as applied\nnanoparticles in water as the base liquid. Liquid film thickness, convective heat transfer coefficient, and dryout length have been\ncalculated. Among the considered nano particles, Al2O3 and TiO2 because of providing more amounts of heat transfer along with\nlonger lengths of dryout found as the most appropriate nanoparticles to achieve cooling objectives....
A series of SO3H-functionalized polymers were prepared and employed as heterogeneous catalysts for one-pot transformation of\nfructose into 5-ethoxymethylfurfural (EMF) that is considered to be one of potential liquid biofuels. A high EMF yield of 72.8%\ncould be obtained at 110�°C for 10 h, and the polymeric acid catalysts could be recycled for five times without significant loss of\ncatalytic performance....
L-Proline derived ionic liquids (ILs) used as both solvent and catalyst were efficient for transformation of fructose and sucrose to 5-\nhydroxymethylfurfural (HMF) in the presence of water. Response surface methodology (RSM) was employed to optimize fructose\ndehydration process, and a maximum HMF yield of 73.6% could be obtained at 90�°C after 50 min. The recycling of the IL exhibited\nan almost constant activity during five successive trials, and a possible reaction mechanism for the dehydration of fructose to HMF\nwas proposed....
The self-diffusion of hydrogen in Ca2+-, Mg2+- and Ba2+-exchanged X zeolites (Mg46X, Ca46X, and Ba46X) has been studied by\nmolecular dynamics (MD) simulations for various temperatures and loadings. The results indicate that in the temperature range of\n77ââ?¬â??298 K and the loading range of 1ââ?¬â??80 molecules/cell, the self-diffusion coefficients are found to range from 1.2 Ã?â?? 10-9 m2Ã?·s-1 to\n2.3 Ã?â?? 10-7 m2Ã?·s-1 which are in good agreement with the experimental values from the quasielastic neutron scattering (QENS) and\npulse field gradients nuclear magnetic resonance (PFG NMR) measurements. The self-diffusion coefficients decrease with loading\ndue to packing of sorbate-sorbatemoleculeswhich causes frequent collusion among hydrogenmolecules in pores and increases with\nincreasing temperature because increasing the kinetic energy of the gas molecules enlarges themean free path of gas molecule. The\nmechanism of diffusion of hydrogenmolecules in these zeolites is transition diffusion. Knudsen diffusion occurs at low loading and\nthe molecular bulk diffusion occurs at higher loading. For given temperature and loading, the self-diffusion coefficients decrease\nin the order Ba46X < Mg46X < Ca46X, due to the different sizes and locations of the divalent cations. Moreover, the effect of\nconcentration of molecular hydrogen on self-diffusion coefficient also is analyzed using radial distribution function (RDF)....
Pore-expanded ordered mesoporous carbons with 2D hexagonal mesostructure were synthesized by a simple nanocasting process.\nWe adopted sucrose as carbon precursors, mesoporous silica materials SBA-15 as the hard templates, and hexane as micelle swelling\nagents.Thepore size distribution ofOMCs was narrowand centered at 5.4 nm,which is larger than the upper limit of pore diameters\ntypically reported for CMK-3. The BET surface area andmesopore volume of PE-CMK-3 can reach to 1213.47m2/g and 1.56 cm3/g,\nrespectively, indicating that choosing large pore size materials as template is good for preparation of high performance of OMCs....
Soybean oil deodorizer distillate (SODD), a byproduct of the soybean oil refining process, is a complex mixture of compounds,\nsuch as free fatty acids (FFA), hydrocarbons, and sterols, such as tocopherols, a class of major natural antioxidants with vitamin\nE activity. As the utilization of SODD for tocopherol extraction is shown to be not economically viable, SODD in the semirefined\nform (neutral) is an interesting alternative to animal and possibly human diet enrichment. This study aimed to evaluate the SODD\nneutralization process varying the alkali (Na2CO3) concentration, temperature, and homogenization time.The optimal conditions\nfor the neutralizing process, in order to obtain the greatest reduction in FFA content, the lowest leaching of tocopherols, and the\ngreatest yield, were the following: Na2CO2 concentration of 4.34N, temperature of 45.8�°C, and homogenization time of 3 min 20 s.\nThe FFA content was reduced from 53.4% to 6.1% after the initial neutralization, thus requiring a second neutralization step. The\nfinal FFA content was of 1.8% and total tocopherol (TT) accounted for about 11% of SODD....
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