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611.
Leila Ahmadian-Alam Vahid Haddadi-Asl Hossein Roghani-Mamaqani Leila Hatami Mehdi Salami-Kalajahi 《Journal of Polymer Research》2012,19(1):9773-12
Atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) was employed to synthesize
well-defined poly (styrene-co-butyl acrylate)/clay nanocomposites. Dodecyltrimethylammonium bromide (DDTMAB) and Vinylbenzyltrimethylammonium
chloride (VBTMAC) surfactants were used as clay modifier. The classical surfactant is used to expand the interlayer gallery
of montmorillonite; however, double bond of reactive modifier participates in chain propagation process and forms clay-attached
polymer chains. Subsequently synthesis of attached and free poly (styrene-co-butyl acrylate) chains and their composition
was confirmed by Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy (1H NMR). Narrow distribution of nanocomposites molecular weight was confirmed by gel permeation chromatography (GPC). Partially
exfoliated clay layers in the copolymer matrix were revealed by X-ray diffraction (XRD) and transmission electron microscopy
(TEM). Thermal properties of the nanocomposites were evaluated by differential scanning calorimetry (DSC) and thermogravimetric
analysis (TGA). Thermal decomposition of the nanocomposites was hindered in the presence of nanoclay. Dynamic mechanical thermal
analysis (DMTA) results show that addition of nanoclay was also resulted in enhanced storage modulus (E′) in comparison with
the neat copolymer. Lower glass transition temperature of nanocomposites was displayed by DSC. 相似文献
612.
Leila Emami Taba Muhammad Faisal Irfan Wan Ashri Mohd Wan Daud Mohammed Harun Chakrabarti 《Renewable & Sustainable Energy Reviews》2012,16(8):5584-5596
Numerous reviews have been found related to individual studies on coal gasification (CG) and biomass gasification (BG). However, this review deals mainly with the CO-gasification (COG) of numerous types of coal and biomass and then compares their results with those obtained using coal and biomass gasification in detail. There are several process parameters which have a direct effect on the gasification process and among them temperature is the most significant one. In this paper, the production of H2, CO2, CO, CH4, and other hydrocarbons in CG, BG and COG with the variation of temperature is reviewed in detail. As it mainly influences the gaseous products and their characteristic behaviour, this review takes into account the effect of temperature on various other parameters such as carbon conversion, gas yield, calorific value, cold gas efficiency as well as tar and char contents in various kinds of coals, biomasses and their mixtures under catalytic or non-catalytic conditions. 相似文献
613.
Andrew Magee Leila Ladani Troy D. Topping Enrique J. Lavernia 《Acta Materialia》2012,60(16):5838-5849
The properties of aluminum alloy (AA) 5083 are shown to be significantly improved by grain size reduction through cryomilling and the incorporation of unmilled Al particles into the material, creating a bimodal grain size distribution consisting of coarse grains in a nanocrystalline matrix. To provide insight into the mechanical behavior and ultimately facilitate engineering applications, the present study reports on the effects of coarse grain ratio, anisotropy, strain rate and specimen size on the elastic–plastic behavior of bimodal AA 5083 evaluated in uniaxial tension tests using a full-factorial experiment design. To determine the governing failure mechanisms under different testing conditions, the specimens’ failure surfaces were analyzed using optical and electron microscopy. The results of the tests were found to conform to Joshi’s plasticity model. Significant anisotropy effects were observed, in a drastic reduction in strength and ductility, when tension was applied perpendicular (transverse) to the direction of extrusion. These specimens also exhibited a smooth, flat fracture surface morphology with a significantly different surface texture than specimens tested in the axial direction. It was found that decreasing specimen thickness and strain rate served to increase both the strength and ductility of the material. The failure surface morphology was found to differ between specimens of different thicknesses. 相似文献
614.
Chouaibi M Mahfoudhi N Rezig L Donsì F Ferrari G Hamdi S 《Journal of the science of food and agriculture》2012,92(6):1171-1177
BACKGROUND: Zizyphus lotus seeds are an unutilized source of vegetable oil and protein and nothing has been reported on their physicochemical characteristics which would indicate the potential uses of these seeds. RESULTS: The percentage composition of the Zizyphus lotus seeds is (on a dry‐weight basis): ash 1.05%, oil 32.92%, protein 19.11%, total carbohydrate 40.87% and moisture 6.05%. Calcium, potassium and magnesium constitute the major minerals of Zizyphus lotus seeds. The seed proteins are rich in threonine, glutamic acid, leucine, arginine and aspartic acid (26.73%, 17.28%, 13.11%, 9.47% and 7.76%, respectively). The main fatty acids of the oil are oleic (61.93%), linoleic (18.31%) and palmitic (9.14%) acids. Glycerol trioleate (OOO; O: oleic acid) was the most abundant triacylglycerol, representing 26.48% of the total triacyglycerols. β‐Tocopherol was the major tocopherol (130.47 mg 100 g?1). This oil was rich in Δ7‐campestrol and β‐sitosterol (147.82 and 82.10 mg 100 g?1 oil), respectively. CONCLUSION: Zizyphus lotus seeds are rich in fat and protein which are of potential industrial significance. In addition, Zizyphus lotus L. seed oil contained many bioactive compounds. This fact is of great economic interest owing to several applications of Zizyphus lotus L. seeds in the food, cosmetics and medicinal industries. Copyright © 2011 Society of Chemical Industry 相似文献
615.
Cyclodextrins (CDs) are cyclic oligosaccharides derived from the enzymatic degradation of starch. Emulsifying functionality of β‐cyclodextrin (β‐CD) upon its complexation with selected solvents (octanol, decane, and toluene) was studied. In several tests, the three‐phase systems containing the emulsion fraction in the middle position were obtained. The examination of variations in the phase behavior of the test systems showed that the decane/β‐CD/water system had the highest emulsion phase volume when β‐CD at concentration of 10% w/v was used. A reduction in interfacial tension (IFT) of the oil–water interface in each test system was observed with the following order: toluene, decane, and octanol. The precipitated fraction obtained upon centrifugation of the emulsion phase, was structurally characterized as the inclusion complex (IC) formed between β‐CD and each of the three test solvents. The wettability of the IC particles was determined through contact angle measurement and formation of the oil‐in‐water (O/W) Pickering emulsions was confirmed (θow<90°). With use of size distribution data, the ICs particles as the microparticles (1–10 µm) were found to be the main species involved in the formation and stabilization of the emulsions. 相似文献
616.
Fouzi Semchedine Louiza Bouallouche-Medjkoune Leila Bennacer Naim Aber Djamil A?ssani 《Wireless Personal Communications》2012,67(2):105-112
This paper investigates the proposition of a new routing protocol for wireless sensor networks called TSRP (Tabu Search based Routing Protocol). In this protocol, we use the mechanism of the meta-heuristic Tabu search to route the data from the sensor (that has sense the events) to the sink. This mechanism is used to select the next sensor that will route the data based on a cost function (considering the energy and the visibility of this sensor compared to the sink). Simulation results, on a car parking application, show that TSRP prolongs the network lifetime than the existing protocols. 相似文献
617.
618.
Leila De Floriani Bianca Falcidieno Caterina Pienovi George Nagy 《Computers & Geosciences》1985,11(6):667-673
The advantages and disadvantages of various digital terrain models are discussed briefly and a new model for triangulating a set of nonuniformly distributed three-dimensional surface observations is described. An algorithm for hierarchical subdivision of a set of data points into nested triangles is proposed. The algorithm selects a subset of the data points which reduce the maximum error between a piecewise linear approximation of the surface using only the selected points and the elevations of the points not selected. The data structure used is such that for any given degree of approximation (in the maximum-error sense) only the necessary points need to be stored. Furthermore, an efficient method is available to approximate the elevation of the surface at any point not included in the original data. The performance of the algorithm is demonstrated experimentally. 相似文献
619.
Leila Jahanshaloo Emad Pouryazdanpanah 《Numerical Heat Transfer, Part A: Applications》2013,63(11):938-953
The Lattice Boltzmann Method (LBM) is a potent numerical technique based on kinetic theory, which has been effectively employed in various complicated physical, chemical, and fluid mechanics problems. In recent years, turbulent flow simulation by using this new class of computational fluid dynamics technique has attracted more attention. In this article, a review of previous studies on turbulence in the frame of LBM is presented. Recent extensions of this method are categorized based on three main groups of turbulence simulation: DNS, LES and RANS methods. 相似文献
620.