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31.
32.
Provas Kumar Roy S. P. Ghoshal S. S. Thakur 《Electrical Engineering (Archiv fur Elektrotechnik)》2010,92(4-5):173-184
In this work, biogeography-based optimization (BBO) is presented for solving different constrained economic load dispatch (ELD) problems combined with economic emission aspects in power system. Nonlinear characteristics of generators like valve point discontinuities, ramp rate limits and prohibited operating zones are considered in the problem. The simulation results show that the proposed BBO algorithm based solutions prove to be the best near-global optimal as compared to the solutions based on Newton–Raphson, Tabu search, genetic algorithm (GA), non-dominated sorting genetic algorithm (NSGA), fuzzy logic controlled genetic algorithm (FCGA), particle swarm optimization (PSO) and differential evolution (DE). 相似文献
33.
Navneet SoinSusanta Sinha Roy Sekhar Chandra RayPatrick Lemoine Md. Anisur RahmanPaul D. Maguire Sushanta K. MitraJames A. McLaughlin 《Thin solid films》2012,520(7):2909-2915
Microstructural properties of ultrathin (1-10 nm) tetrahedral amorphous carbon (ta-C) films are investigated by Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy, X-ray Photoelectron Spectroscopy, Raman spectroscopy and Atomic Force Microscopy (AFM). The CK-edge NEXAFS spectra of 1 nm ta-C films provided evidence of surface defects (C―H bonds) which rapidly diminish with increasing film thickness. A critical thickness for stabilization of largely sp3 matrix structure distorted by sp2 sites is observed via the change of π*C═C peak behavior. Meanwhile, an increase in the film thickness promotes an enhancement in sp3 content, the film roughness remains nearly constant as probed by spectroscopic techniques and AFM, respectively. The effect of thickness on local bonding states of ultrathin ta-C films proves to be the limiting factor for their potential use in magnetic and optical storage devices. 相似文献
34.
Wei Yuan Sushanta K. Panigrahi Rajiv S. Mishra 《Metallurgical and Materials Transactions A》2013,44(8):3675-3684
Friction stir processing (FSP) is emerging as an effective tool for microstructural modification and property enhancement. As-cast AZ91 magnesium alloy was friction stir processed with one-pass and two-pass to examine the influence of processing conditions on microstructural evolution and corresponding mechanical properties. Grain refinement accompanied with development of strong basal texture was observed for both processing conditions. Ultrafine-grained (UFG) AZ91 was achieved under two-pass FSP with fine precipitates distributed on the grain boundary. The processed UFG AZ91 exhibited a high tensile strength of ~435 MPa (117 pct improvement) and tensile fracture elongation of ~23 pct. The promising combination of strength and ductility is attributed to the elimination of casting porosity, and high density of fine precipitates in an UFG structure with quite low dislocation density. The effects of grain size, precipitate, and texture on deformation behavior have been discussed. 相似文献
35.
Kaushik Ghoshal T.R.G. Kutty Sudhir Mishra Arun Kumar 《Journal of Nuclear Materials》2013,432(1-3):20-22
Creep behavior of U–7%Zr, U–5%Zr–2%Nb, U–3.5%Zr–3.5%Nb, U–2%Zr–5%Nb, U–7%Nb alloys (composition in wt.%) was investigated by the impression creep technique at 630 and 700 °C at a stress of 22.2 MPa. Creep rate was found to be two orders lower in the binary U–7%Nb than the U–7%Zr alloy. In ternary U–Nb–Zr alloys, the creep rate was found decreasing drastically with the increase in Nb content. 相似文献
36.
Rafael Luque Sushanta K. Badamali James H. Clark Macarena Fleming Duncan J. Macquarrie 《Applied Catalysis A: General》2008,341(1-2):154-159
A smart and greener microwave approach to the selective oxidation of cyclohexene is reported whereby, depending on the reaction conditions, the epoxide (65% conversion, 75% selectivity), the enol (70% conversion, 80% selectivity) or the enone (>99% conversion, 89% selectivity) can be obtained in a short period of time ranging from 1 to 20 min. A cobalt-salen-SBA-15 material was employed as catalyst. The reported solventless microwave protocol was simple, greener and more efficient compared to any other reported cyclohexene oxidations. 相似文献
37.
Alireza Samavati Zulkafli Othaman Sib Krishna Ghoshal Mohammad Reza Dousti Mohammed Rafiq Abdul Kadir 《International journal of molecular sciences》2012,13(10):12880-12889
The visible luminescence from Ge nanoparticles and nanocrystallites has generated interest due to the feasibility of tuning band gap by controlling the sizes. Germanium (Ge) quantum dots (QDs) with average diameter ~16 to 8 nm are synthesized by radio frequency magnetron sputtering under different growth conditions. These QDs with narrow size distribution and high density, characterized using atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) are obtained under the optimal growth conditions of 400 °C substrate temperature, 100 W radio frequency powers and 10 Sccm Argon flow. The possibility of surface passivation and configuration of these dots are confirmed by elemental energy dispersive X-ray (EDX) analysis. The room temperature strong visible photoluminescence (PL) from such QDs suggests their potential application in optoelectronics. The sample grown at 400 °C in particular, shows three PL peaks at around ~2.95 eV, 3.34 eV and 4.36 eV attributed to the interaction between Ge, GeOx manifesting the possibility of the formation of core-shell structures. A red shift of ~0.11 eV in the PL peak is observed with decreasing substrate temperature. We assert that our easy and economic method is suitable for the large-scale production of Ge QDs useful in optoelectronic devices. 相似文献
38.
Chang W Klemm S Beaulieu C Hawari J Whyte L Ghoshal S 《Environmental science & technology》2011,45(3):1061-1066
Several studies have shown that biostimulation in ex situ systems such as landfarms and biopiles can facilitate remediation of petroleum hydrocarbon contaminated soils at sub-Arctic sites during summers when temperatures are above freezing. In this study, we examine the biodegradation of semivolatile (F2: C10-C16) and nonvolatile (F3: C16-C34) petroleum hydrocarbons and microbial respiration and population dynamics at post- and presummer temperatures ranging from -5 to 14 °C. The studies were conducted in pilot-scale tanks with soils obtained from a historically contaminated sub-Arctic site in Resolution Island (RI), Canada. In aerobic, nutrient-amended, unsaturated soils, the F2 hydrocarbons decreased by 32% during the seasonal freeze-thaw phase where soils were cooled from 2 to -5 °C at a freezing rate of -0.12 °C d(-1) and then thawed from -5 to 4 °C at a thawing rate of +0.16 °C d(-1). In the unamended (control) tank, the F2 fraction only decreased by 14% during the same period. Biodegradation of individual hydrocarbon compounds in the nutrient-amended soils was also confirmed by comparing their abundance over time to that of the conserved diesel biomarker, bicyclic sesquiterpanes (BS). During this period, microbial respiration was observed, even at subzero temperatures when unfrozen liquid water was detected during the freeze-thaw period. An increase in culturable heterotrophs and 16S rDNA copy numbers was noted during the freezing phase, and the (14)C-hexadecane mineralization in soil samples obtained from the nutrient-amended tank steadily increased. Hydrocarbon degrading bacterial populations identified as Corynebacterineae- and Alkanindiges-related strains emerged during the freezing and thawing phases, respectively, indicating there were temperature-based microbial community shifts. 相似文献
39.
The composition of the pyrolysis products of plastics depends on disintegration of the macromolecule into variety of hydrocarbon fractions. In this work, a detailed gas chromatographic study of pyrolysis products of polypropylene (PP) between 200 and 600°C was carried out. The pyrograms have been analyzed in terms of amount of different products evolved at various pyrolysis temperatures. At low pyrolysis temperatures (200–300°C), the yield of lighter hydrocarbons (C5‐C10) is low; it gradually increases until maximum decomposition temperature (446°C) and decreases thereafter. The following reaction types were considered to explain the decomposition mechanism of PP: (a) main chain cleavage to form chain‐ terminus radicals; (b) intramolecular hydrogen transfer to generate internal radicals; (c) intermolecular hydrogen transfer to form both volatile products and radicals; and (d) β‐scission to form both volatiles and terminally unsaturated polymer chains. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
40.
Sanjay K. Nayak Smita Mohanty Sushanta K. Samal 《Polymer-Plastics Technology and Engineering》2013,52(9):976-988
In the present investigation Polypropylene–Maleic anhydride grafted polypropylene–organically modified MMT (PP-MAPP-OMMT) nanocomposites were prepared by melt mixing in a twin screw extruder followed by injection molding. The effect of clay chemistry and compatibilizer on the properties of the nanocomposites has been studied. Sodium montmorillonite has been organically modified using quaternary and alkyl amine intercalants. A comparative account with commercial quaternary ammonium modified clays i.e Cloisite 20A, Cloisite 15A and Cloisite 30B has been presented. Storage modulus of PP matrix also increased in the nanocomposites, indicating an increase in the stiffness of the matrix polymer with the addition of organically modified nanoclays. The morphology of the nanocomposites has been examined using wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). Morphological findings revealed efficient dispersion of organically modified nanoclays within the PP matrix. MAPP compatibilized PP/Cloisite 15A nanocomposites displayed finely dispersed exfoliated nanomorphology as compared with other systems. 相似文献