02574nas a2200373 4500008004100000022001400041245014200055210006900197260000800266490000700274520138700281653001501668653001501683653002401698653001101722653001601733653002601749653001301775653001401788653001801802653002101820653001701841653002301858653002801881653002801909653001501937100002101952700001801973700002001991700002102011700001802032700001902050856013102069 2017 eng d a1350-417700aIntensification of extraction of curcumin from Curcuma amada using ultrasound assisted approach: Effect of different operating parameters0 aIntensification of extraction of curcumin from Curcuma amada usi cSEP0 v383 a

Curcumin, a dietary phytochemical, has been extracted from rhizomes of Curcuma amada using ultrasound assisted extraction (UAE) and the results compared with the conventional extraction approach to establish the process intensification benefits. The effect of operating parameters such as type of solvent, extraction time, extraction temperature, solid to solvent ratio, particle size and ultrasonic power on the extraction yield have been investigated in details for the approach UAE. The maximum extraction yield as 72% was obtained in 1 h under optimized conditions of 35 degrees C temperature, solid to solvent ratio of 1:25, particle size of 0.09 mm, ultrasonic power of 250 W and ultrasound frequency of 22 kHz with ethanol as the solvent. The obtained yield was significantly higher as compared to the batch extraction where only about 62% yield was achieved in 8 h of treatment. Peleg's model was used to describe the kinetics of UAE and the model showed a good agreement with the experimental results. Overall, ultrasound has been established to be a green process for extraction of curcumin with benefits of reduction in time as compared to batch extraction and the operating temperature as compared to Soxhlet extraction.

10aAcrylamide10aCavitation10aCurcumin Extraction10aDesign10aEnhancement10aFunctionalized Silica10akinetics10aMicrowave10aNanoparticles10aNatural-products10aOptimization10aPhenolic-compounds10aProcess Intensification10aSolid-liquid Extraction10aUltrasound1 aShirsath, S., R.1 aSable, S., S.1 aGaikwad, S., G.1 aSonawane, S., H.1 aSaini, D., R.1 aGogate, P., R. uhttps://library.ncl.res.in/content/intensification-extraction-curcumin-curcuma-amada-using-ultrasound-assisted-approach-effect02798nas a2200325 4500008004100000022001400041245009300055210006900148260000800217490000800225520177900233653002002012653001602032653003402048653002402082653001802106653001802124653002302142653000902165653001402174653001502188653001502203653002502218653003002243653002402273653001402297100002102311700002502332856011502357 2017 eng d a0927-775700aRole of base fluid on the thermal conductivity of oleic acid coated magnetite nanofluids0 aRole of base fluid on the thermal conductivity of oleic acid coa cSEP0 v5293 a

Thermal conductivity enhancement of nanofluids of oleic acid coated magnetite nanoparticles dispersed in four different base fluids (toluene, xylene, mesitylene, kerosene) is studied to understand the role of the solvent (base fluid). From the correlation of the thermophysical properties of the base fluid with the thermal conductivity of the corresponding nanofluid, it is found that the nanofluid with the base fluid of lower intrinsic thermal conductivity and dielectric constant shows relatively larger enhancement in the thermal conductivity. A linear increase in the thermal conductivity with increasing viscosity is observed for all four nanofluids studied. The concentration dependent thermal conductivity studies showed enhancement only above a particular concentration, within the sensitivity of the measurement, and this critical concentration is different for the different nanofluids. The nanofluid with kerosene showed the lowest critical concentration for thermal conductivity enhancement compared to the other nanofluids. The difference between the experimental thermal conductivity and the calculated value using the Maxwell model is found to depend on the critical concentration. By assuming the critical concentration as the zero concentration, it is found that all the studied nanofluids almost follow the Maxwell model of thermal conductivity. Thus, for the dispersions of the same oleic acid coated magnetite nanoparticles, the base fluid affects the critical concentration for thermal conductivity enhancement, probably due to the interfacial effects arising from the surfactant-solvent interactions.

10aBrownian-Motion10aEnhancement10aHeat-transfer Characteristics10aMagnetic nanofluids10aMaxwell model10aNanoparticles10aParticle Migration10aSize10astability10aSuspension10aTemprature10aThermal conductivity10aThermophysical properties10atransport mechanism10aviscosity1 aLenin, Ramanujam1 aJoy, Pattayil, Alias uhttps://library.ncl.res.in/content/role-base-fluid-thermal-conductivity-oleic-acid-coated-magnetite-nanofluids02540nas a2200253 4500008004100000022001400041245013000055210006900185260000800254490000800262520161400270653001101884653001301895653001601908653001101924653001101935653001101946653002301957653010301980653003002083100002102113700002502134856012702159 2017 eng d a0021-979700aStudies on the role of unsaturation in the fatty acid surfactant molecule on the thermal conductivity of magnetite nanofluids0 aStudies on the role of unsaturation in the fatty acid surfactant cNOV0 v5063 a

To study the role of unsaturation in the surfactant molecule on the thermal conductivity of magnetite nanofluids, four different fatty acid (stearic, oleic, linoleic, and linolenic acids with different degree of unsaturation) coated magnetite nanoparticles of comparable size are prepared and dispersed in toluene. It is found that the nanofluid with the saturated fatty acid coated nanoparticles show larger viscosity than the fluid with the unsaturated fatty acid coated particles at all concentrations. Thermal conductivity studies show enhancement only above a critical concentration for all fluids. The critical concentration for thermal conductivity enhancement varies with the surfactant, possibly due to the difference in the degree of aggregation of the nanoparticles in the fluid, because of the difference in the conformation of the surfactant molecules on the nanoparticle's surface. The experimental thermal conductivity follows the Maxwell model at higher concentrations. From the overall studies, it is observed that the thermal conductivity of the fluids with aggregated or assembled nanoparticles shows slightly larger enhancement than that of the fluids with isolated particles. However, in the presence of a magnetic field, the fluids with isolated nanoparticles showed relatively larger enhancement, possibly due to the easy response of the isolated magnetite nanoparticles to the applied field. (C) 2017 Elsevier Inc. All rights reserved.

10aChains10aDynamics10aEnhancement10aFields10aFluids10aForces10agold nanoparticles10aMagnetic fluid; Nanofluid; Surfactant; Unsaturation; Conformation; Thermal conductivity; Viscosity10aSelf-assembled Monolayers1 aLenin, Ramanujam1 aJoy, Pattayil, Alias uhttps://library.ncl.res.in/content/studies-role-unsaturation-fatty-acid-surfactant-molecule-thermal-conductivity-magnetite