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排序方式: 共有254条查询结果,搜索用时 15 毫秒
131.
Low-temperature oxidation (LTO) of the Fosterton crude oil mixed with its reservoir sand has been investigated in a tubular reactor. Reservoir sand saturated with 15 wt% of crude oil (20.5° API gravity) was subjected to air injection at low-temperature (220 °C) for a period of time (17 h and 30 min), resulting in the formation of an oxygenated hydrocarbon fuel. The vent gases were analyzed for the content of CO, CO2, and oxygen and the residue was analyzed to determine the elemental composition and calorific value. The presence of LTO region was verified from the values of apparent H/C ratio. In addition, thermal behavior and combustion kinetics of the residue was investigated using thermogravimetric analysis (TGA). TG involves both non-isothermal and isothermal analysis and kinetic data was derived from isothermal studies. The general model for nth order reaction was used to obtain the kinetic parameters of the coke oxidation reaction. The activation energy, frequency factor and order of the reactions were determined using the model. 相似文献
132.
133.
S. Murugan S. Dhanapandian C. Manoharan K. R. Murali 《Journal of Materials Science: Materials in Electronics》2013,24(2):483-488
In this work, the pulse electrodeposition technique has been employed for the first time to deposit AgGaSe2 films. The films were deposited at room temperature from a bath containing Analar grade 10 mM silver nitrate, 10 mM gallium nitrate and 10 mM SeO2. The deposition potential was maintained as—0.68 V (SCE). Tin oxide coated glass substrates (5.0 ohms/sq) was used as the substrate. The duty cycle was varied in the range of 6–50 %. The XRD profile of the thin films deposited at different duty cycles indicate the peaks corresponding to AgGaSe2. Atomic force microscopy studies indicated that the surface roughness increased from 0.95 to 1.25 nm with duty cycle. The transmission spectra exhibited interference fringes. Refractive index of 2.71 was observed in the wavelength range 600–1,000 nm. Electrochemical Impedance studies indicated a single semicircle. The grain boundary resistance decreased with increase of duty cycle. 相似文献
134.
We report here a microwave‐assisted solvothermal (MW‐ST) method to synthesise carbon‐supported multimetallic nanostructured alloys of Pt, Pd and Co with high crystallinity and homogeneity for electrocatalytic application in fuel cells. Multimetallic nanoalloy electrocatalysts have been synthesised by a one‐pot, rapid MW‐ST method within 15 min at <300 °C without any post‐annealing in reducing gas atmospheres. For a comparison, same multimetallic alloys were also synthesised by heat treatment of co‐precipitated metals. Significant differences were observed in the phase structure and surface composition of the alloys synthesised by the two methods, which were rationalised based on the synthesis procedures adopted. Further, the multimetallic alloys were also explored for their electrocatalytic applications as cathode catalysts for oxygen reduction reaction (ORR). The multimetallic alloys, synthesised by the MW‐ST method, show much higher ORR activity compared to their counterparts synthesised by the conventional borohydride reduction method. While the ORR activity of Pt70Pd20Co10 is comparable to that of commercial Pt, the ORR activity of Pt50Pd30Co20 in direct methanol fuel cells (DMFC) is superior to that of commercial Pt at high methanol concentrations due to its high tolerance to methanol that may crossover from the anode to the cathode. 相似文献
135.
136.
Akon Higuchi Qing-Dong Ling S. Suresh Kumar Murugan Munusamy Abdullah A. Alarfajj Akihiro Umezawa Gwo-Jang Wu 《Progress in Polymer Science》2014
This review describes recent developments regarding the use of natural and synthetic polymers to support the propagation of human pluripotent stem cells (hPSCs), human embryonic stem cells (hESCs), and induced pluripotent stem cells (hiPSCs) while maintaining pluripotency in feeder-free and xeno-free cultures. The development of methods for culturing these cells without using mouse embryonic fibroblasts (MEFs) as a feeder layer will enable more reproducible culture conditions and reduce the risk of xenogenic contaminants, thus increasing the potential clinical applications of differentiated hPSCs. Human or recombinant fibronectin, laminin-511, and vitronectin, which are components of the extracellular matrix (ECM), have been used instead of Matrigel for the feeder-free growth of undifferentiated hPSCs. Successful hPSC cultures have been described for the following conditions: on oligopeptide-immobilized surfaces derived from vitronectin, on microcarriers prepared from synthetic polymers, and encapsulated within three-dimensional (3D) hydrogels composed of alginate and other hydrophilic natural polymers. Recently, synthetic biomaterials that allow hPSCs to maintain pluripotency by secreting endogenous ECM components have been designed. The combination of human ECM proteins or cell adhesion molecules (e.g., oligopeptides and poly-d-lysine) and synthetic biomaterials with well-designed surfaces and/or structures (e.g., scaffolds, hydrogels, microcarriers, microcapsules, or microfibers) in the presence of a chemically defined medium containing recombinant growth factors would offer a xeno-free alternative to feeder cells for culturing hPSCs and maintaining their pluripotency. 相似文献
137.
Vijayan Vijeesh Murugan Siva Prasad Ji Changwook Son Seong-Guk Park Yeong-Do 《Journal of Mechanical Science and Technology》2021,35(11):5137-5142
Journal of Mechanical Science and Technology - Among various defects formed in resistance spot welds of advanced high strength steels (AHSS), shrinkage voids are seldomly studied. Apparently, the... 相似文献
138.
R. Sudhakaran V. VeL Murugan P. S. Sivasakthivel M. Balaji 《The International Journal of Advanced Manufacturing Technology》2013,64(9-12):1487-1504
The prediction of delta ferrite content expressed in terms of ferrite number in austenitic stainless steel welds is very helpful in assessing its performance. The final ferrite content determines the properties of weldments such as strength, toughness, corrosion resistance, and phase stability. This paper presents a study on the effect of process parameters on ferrite number in 202 grade stainless steel gas tungsten arc welded plates (GTAW). Experiments were conducted based on response surface methodology. The ferrite number was determined by using a ferrite scope and by using DeLong diagram. A mathematical model was developed correlating the important controllable GTAW process parameters like welding gun angle, welding speed, plate length, welding current, and shielding gas flow rate with ferrite number. The adequacy of the model was checked using analysis of variance technique. The developed model is very useful to quantitatively determine the ferrite number. The main and interaction effects of the process parameters are presented in graphical form that helps in selecting quickly the process parameters to achieve the desired results. 相似文献
139.
Recycling of high-volume polyolefin-based packaging wastes in India is challenging, as they have low recycle value, high levels of contamination, and lack of direct processing methods. This work discusses a two-stage mechanical processing method for recycling the polyolefin-based plastic wastes that are not conventionally recycled. With the objective of improving specific properties like sound absorption and noise reduction, inhomogeneities were introduced in the recycled product. This was achieved by mixing polyolefin-based packaging wastes with other waste materials such as plastic-coated aluminium foils, expanded polystyrene, and coir pith in varying quantities. More than 30 times volume reduction was achieved by a two-stage compression molding process. The sound absorption properties of the recycled materials are found to be comparable to expanded polystyrene and glass wool when small quantities (2–3 wt%) of materials like expanded polystyrene waste and coir pith were added. Impact strength of the recycled material decreased with increasing amounts of secondary additives like metal foils. Flexural strength of the recycled material was found to be maximum at about 30 wt% of metal foils. The end product could find applications in the construction industry due to the sound-absorption properties and the mechanical strength. 相似文献
140.
Western Bolaños Joan J. Carvajal Xavier Mateos Ganapathy Senthil Murugan Ananth Subramanian James S. Wilkinson Eugenio Cantelar Ginés Lifante Magdalena Aguiló Francesc Díaz 《Optical Materials》2011,34(2):475-480
CW mirrorless laser operation at 1840 nm at room temperature was observed in buried rib waveguides of KY0.58Gd0.22Lu0.17Tm0.03(WO4)2 fabricated by structuring KY(WO4) substrates by Ar-ion milling and subsequent liquid phase epitaxial growth of the active layer on these substrates. Laser efficiency and laser threshold seems to change with the width of the channels fabricated. 相似文献