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11.
In this research, the effect of NbF5 as an additive on the hydrogen desorption kinetics of MgH2 was investigated and compared to TiH2, Mg2Ni and Nb2O5 catalysts. The kinetics measurements were done using a method in which the ratio of the equilibrium plateau pressure to the opposing pressure was the same for all the reactions. The data showed NbF5 to be vastly superior to the other catalysts for improving the desorption kinetics of MgH2. The rates of desorption were found to be in the order NbF5 ? Nb2O5 > Mg2Ni > TiH2 > Pure MgH2. Kinetic modeling measurements showed that chemical reaction at the phase boundary to be the likely process controlling the reaction rates. TPD analyses showed the mixture with NbF5 has the lowest desorption temperature although it was accompanied with some weight penalty. 相似文献
12.
Abouelkacem Qaiss Hassan Saidi Omar Fassi‐Fehri Mosto Bousmina 《Polymer Engineering and Science》2012,52(12):2637-2644
Cellular polypropylene‐calcium carbonate based piezoelectric films were obtained using biaxial stretching and gas‐mediated inflation followed by a corona discharge treatment using home‐made devices. The obtained results revealed a cellular structure that develops at the interface between the solid particles and the polymer matrix and the final piezoelectric coefficient was found to depend both on the gas pressure profile and on time. The inflation step gives better results when the gas pressure is increased in stepwise manner allowing the gas to adequately intrude the cavities and maintain the required pressure. The overall results are discussed in terms of processing conditions and in terms of the developed microstructure. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers 相似文献
13.
Azim Ziyaei Halimehjani M. Ali Alaei Farzaneh Soleymani Movahed Negin Jomeh Mohammad R. Saidi 《Journal of Sulfur Chemistry》2016,37(5):529-536
An effective approach for the synthesis of 2-(alkylthio)thiazol-4(5H)-ones from alkyl dithiocarbamates and chloroacetyl chloride in the presence of NaHCO3 has been developed. Good to excellent yields of products, simple reaction conditions and general applicability are the most important advantages of this protocol. 相似文献
14.
Propane dehydrogenation on a commercial Pt-Sn/Al2O3 catalyst in a Pd-Ag membrane reactor is considered. A mathematical model is developed to evaluate the performance of the catalytic membrane reactor for the process of propane dehydrogenation. Design and operating conditions are systematically evaluated for key performance metrics such as propane conversion, propylene selectivity, hydrogen selectivity, and hydrogen recovery under different operating conditions. The results confirm that the high performance of the membrane reactor is related to the continuous removal of hydrogen from the reaction zone to shift the reaction equilibrium towards the formation of more propylene and hydrogen. 相似文献
15.
16.
Ali Hemmatifar Mohammad Said Saidi Arman Sadeghi Mahdi Sani 《Microfluidics and nanofluidics》2013,14(1-2):265-276
Dielectrophoresis (DEP) is an electrokinetic phenomenon which is used for manipulating micro- and nanoparticles in micron-sized devices with high sensitivity. In recent years, electrode-based DEP by patterning narrow oblique electrodes in microchannels has been used for particle manipulation. In this theoretic study, a microchannel with triangular electrodes is presented and a detailed comparison with oblique electrodes is made. For each shape, the behavior of particles is compared for three different configurations of applied voltages. Electric field, resultant DEP force, and particle trajectories for configurations are computed by means of Rayan native code. The separation efficiency of the two systems is assessed and compared afterward. The results demonstrate higher lateral DEP force, responsible for particle separation, distributed wider across the channel width for triangular shape electrodes in comparison with the oblique ones. The proposed electrode shape also shows the ability of particle separation by attracting negative DEP particles to or propelling them from the flow centerline, according to the configuration of applied voltages. A major deficiency of the oblique electrodes, which is the streamwise variation of the lateral DEP force direction near the electrodes, is also eliminated in the proposed electrode shape. In addition, with a proper voltages configuration, the triangular electrodes require lower voltages for particle focusing in comparison with the oblique ones. 相似文献
17.
Synergistic effect of organoclay fillers based on fluorinated surfmers for preparation of polystyrene nanocomposites
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Chahinez Benbayer Salima Saidi‐Besbes Elisabeth Taffin de Givenchy Sonia Amigoni Frédéric Guittard Aicha Derdour 《应用聚合物科学杂志》2015,132(33)
Novel fluorinated reactive surfactants were used for the organic modification of monmorillonite clays. These organoclays were used for the preparation of polystyrene?clay nanocomposites by in‐situ free radical polymerization. Reference systems based on hydrocarbon homologous surfmer and nonpolymerizable surfactants were also used to deduce the effect of the fluorine moiety and the polymerizable function on the morphology and thermal stability of the prepared nanocomposites. Different structural parameters of the surfactants were investigated and modulated for the clay modification including: the nature of surfactant (surfmer/classical surfactant, fluorinated, or hydrocarbonated), the length of the fluorinated chain as well as the length of the hydrocarbon spacers linking the ammonium head to the fluorine chain or the polymerizable acrylic function. Wide angle‐X‐ray scattering (WAXD), thermogravimetric analysis (TGA), and electronic microcopies (TEM and SEM) were used to establish a structure‐morphology, thermal properties relationships, and to highlight the key parameters governing the exfoliation process. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42347. 相似文献
18.
The effect of flow pulsations is studied via a discrete element model on hydrodynamics of spouted bed, which is being used in many important industries like drying processes. Decreased horizontal air percolation and preserving upward momentum, increased particle circulation, increased particle traverse distance, and better homogeneity are resulted from flow pulsations in spouted beds. Among the waveforms studied, square and triangular waveforms differ most and least from steady spouting, respectively. The predictions indicate that the pulsed spouted bed has the potential to enhance both gas and particle motion, hence being useful in drying and other operations. 相似文献
19.
Effects of pH and chloride concentration on pitting corrosion of AA6061 aluminum alloy 总被引:1,自引:0,他引:1
Effects of pH solution and chloride (Cl−) ion concentration on the corrosion behaviour of alloy AA6061 immersed in aqueous solutions of NaCl have been investigated using measurements of weight loss, potentiodynamic polarisation, linear polarisation, cyclic polarisation experiment combined with open circuit potential transient technique and optical or scanning electron microscopy.The corrosion behaviour of the AA6061 aluminum alloy was found to be dependant on the pH and chloride concentration [NaCl] of solution. In acidic or slightly neutral solutions, general and pitting corrosion occurred simultaneously. In contrast, exposure to alkaline solutions results in general corrosion. Experience revealed that the alloy AA6061 was susceptible to pitting corrosion in all chloride solution of concentration ranging between 0.003 wt% and 5.5 wt% NaCl and an increase in the chloride concentration slightly shifted both the pitting Epit and corrosion Ecor potentials to more active values. In function of the conditions of treatment, the sheets of the alloy AA6061 undergo two types of localised corrosion process, leading to the formation of hemispherical and crystallographic pits.Polarisation resistance measurements in acidic (pH = 2) and alkaline chloride solutions (pH = 12) which are in good agreement with those of weight loss, show that the corrosion kinetic is minimised in slightly neutral solutions (pH = 6). 相似文献
20.
Kamel Eddine El Mecherfi Djamel Saidi Omar Kheroua Ghazalia Boudraa Mahmoud Touhami Olivier Rouaud S��bastien Curet Yvan Choiset Hanitra Rabesona Jean-Marc Chobert Thomas Haertl�� 《European Food Research and Technology》2011,233(5):859-867
Effect of combined microwave (MW) and enzymatic hydrolysis on the human immunoglobulin E (IgE)-binding properties of ??-lactoglobulin (??-lg) and other whey proteins (WP) was investigated. Separated ??-lg and full whey protein isolate (WPI) were hydrolyzed with trypsin, chymotrypsin, mixture of trypsin/chymotrypsin, and pepsin at three microwave power levels: 50?W during 1 and 5?min, 100 and 200?W during 1 and 3?min. The immunoreactivity of the obtained hydrolysates resulting from combined microwave protease treatment was assessed using sera of young patients allergic to bovine whey proteins. The application of microwave treatment at 200?W enhances the hydrolysis of ??-lg by pepsin in 3?min and decreases significantly its immunoreactivity. The extensive hydrolysis of the microwave-treated ??-lg and WPI with trypsin, chymotrypsin, and the mixture of trypsin with chymotrypsin did not have an impact on the IgE binding of the products obtained in all the studied conditions. 相似文献