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Kalidasan K.,Arulmigu Palani Andavar College Of Arts | Kanna P.R.,Velammal College of Engineering and Technology
Journal of the Taiwan Institute of Chemical Engineers | Year: 2016

A finite difference based two dimensional numerical analysis of laminar natural convection inside the open square enclosure containing nanofluid of water with multi-walled carbon nanotube (MWCNT) is presented by stream function-vorticity approach. The left wall is subjected to sinusoidal time-variant temperature. The top and bottom walls are considered as adiabatic and the right wall is kept as ambient. The flow is diagonally downward and opposed by the buoyancy force. In the numerical analysis, Xue [30] model of thermal conductivity is coupled with modified Krieger and Dougherty (K-D) model of viscosity based on rheology of suspension of particles. The variables considered in the present study are Rayleigh number (104-106), volumetric fraction of MWCNT (0<φ<1.5%), amplitude (0

Manimegalai S.,Arulmigu Palani Andavar College Of Arts | Manjula P.,A PA College for Women
Journal of Materials and Environmental Science | Year: 2015

The Phaeophyceae or brown algae is a large group of marine multicelluar algae and play an important role in marine environments both as food, medicines and industrial purposes. In present study, the inhibition effect of methanolic extract of Sargassum swartzii (brown algae) and Zn 2+ ions (100 ppm) on the corrosion of mild steel in aqueous medium containing 60ppm Cl- ion was studied by weight loss method at 303 K - 343 K. The energy of activation , adsorption and thermodynamic parameters were evaluated from the results of temperature study. The inhibition efficiency increased with increase in the inhibitor concentration and decreased with rise in temperature. Sargassum swartzii (SS) extract is brought about by the increasing its activation energy(Ea) as a result of adsorption is physical adsorption. The adsorption of Sargassum swartzii on mild steel surface was found to obey Langmuir , Temkin and Freundlich adsorption isotherms. ΔG°ads value indicated a strong and spontaneous adsorption of the SS extract components on the metal surface. Thus, it can be concluded that Sargassum swartzii - Zn2+ inhibitor system acted as a good inhibitor in aqueous medium.

Devaraju S.,Anna University | Vengatesan M.R.,Anna University | Ashok Kumar A.,Arulmigu Palani Andavar College Of Arts | Alagar M.,Anna University
Journal of Sol-Gel Science and Technology | Year: 2011

New type of Polybenzoxazine-silica (PBZ-SiO2) hybrid nanocomposites was prepared through in situ sol-gel method. Benzoxazine was synthesized using bisphenol-A, trans-4-aminocyclohexanol hydrochloride and formaldehyde solution through Mannich condensation reaction and was characterized by FT-IR, 1HNMR and 13CNMR spectroscopy. The methodology adopted in the present study involves to formation of hydrogen bond interaction between the benzoxazine monomer and the silica matrix, followed by the ring opening polymerization of benzoxazine monomer through thermal curing to obtain a red brown transparent PBZ-SiO2 hybrid. The formation of hybrid nanocomposites was confirmed by FT-IR. Thermal and morphological properties of the hybrid materials were investigated by the differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), scanning electron microscopy (SEM). The PBZ-SiO2 hybrids show improved thermal properties and glass transition (Tg) temperature. The nitrogen porosimetry study was carried out to confirm the nanometer level integration of polybenzoxazine in the PBZ-SiO2 hybrid nanocomposites. © 2011 Springer Science+Business Media, LLC.

Kalidasan K.,Arulmigu Palani Andavar College Of Arts | Velkennedy R.,Thiagarajar College of Engineering | Rajesh Kanna P.,Velammal College of Engineering and Technology
Applied Thermal Engineering | Year: 2016

A finite difference based two dimensional numerical investigation of laminar natural convection inside the closed square enclosure filled with copper-water nanofluid and two diagonally placed adiabatic blocks is presented by vorticity-stream function approach. The left and right walls are assumed as hot and the top wall is kept as cold. The temperature of bottom wall varies sinusoidal over time. The variables considered in the present study are Rayleigh number (104 to 106), volumetric fraction of copper particles (0 < φ < 4%), amplitude (0 < a < 0.5) and the period (0.001 < τ < 0.8). The periodic results of fluid flow are elucidated with Streamlines, Isotherms and Nusselt number. The combined effect of nanofluid and time-variant temperature at the bottom wall suppresses the hydrodynamic blockage effect of solid blocks and enhanced the convective heat transfer. The time-averaged local Nu is increased by a maximum of 11% when comparing with pure fluid. © 2015 Elsevier Ltd. All rights reserved.

Swarnalatha N.,Tamil University | Gunasekaran S.,Tamil University | Muthu S.,Sri Venkateswara College of Engineering | Nagarajan M.,Arulmigu Palani Andavar College Of Arts
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

Experimental and theoretical investigations on the molecular structure, electronic and vibrational characteristics of 9-methoxy-2H-furo[3,2-g]chromen-2-one (9M2HFC) were presented. The vibrational frequencies were obtained by DFT/B3LYP calculations employing 6-311++G(d,p) basis set, were compared with experimental FT-IR and FT-Raman spectral data. The FT-IR spectrum (4000-400 cm-1) and FT-Raman spectrum (4000-100 cm-1) in solid phase were recorded for 9M2HFC. The geometry of the title compound was fully optimized. Quantum chemical calculations of the equilibrium geometry, the complete vibrational assignments of wavenumbers using potential energy distribution (PED) calculated with scaled quantum mechanics infrared intensities, Raman activities of the title molecule was reported. HOMO-LUMO energies, molecular electrostatic potential, Mulliken population analysis on atomic charges, natural bond orbital (NBO) analysis, non linear optical behavior in terms of first order hyperpolarizability, and thermodynamic properties of the title molecule were carried out. Finally, simulated FT-IR and FT-Raman spectra showed good agreement with the observed spectra. © 2014 Elsevier B.V. All rights reserved.

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