Time filter

Source Type

Mani Rajan M.S.,Anna University | Mahalingam A.,Anna University | Uthayakumar A.,Presidency College at Chennai
Annals of Physics | Year: 2014

We investigated the soliton solution for N coupled nonlinear Schrödinger (CNLS) equations. These equations are coupled due to the cross-phase-modulation (CPM). Lax pair of this system is obtained via the Ablowitz-Kaup-Newell-Segur (AKNS) scheme and the corresponding Darboux transformation is constructed to derive the soliton solution. One and two soliton solutions are generated. Using two soliton solutions of 3 CNLS equation, nonlinear tunneling of soliton for both with and without exponential background has been discussed. Finally cascade compression of optical soliton through multi-nonlinear barrier has been discussed. The obtained results may have promising applications in all-optical devices based on optical solitons, study of soliton propagation in birefringence fiber systems and optical soliton with distributed dispersion and nonlinearity management. © 2014 Elsevier Inc.

Leelavathy C.,Quaid E Millath Government College W | Antony S.A.,Presidency College at Chennai
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

(Chemical Equation Presented) Novel metal(II) complexes derived from furfurylidene-4-aminoantipyrine and 2-aminobenzothiazole were synthesized and characterized by spectroscopic (IR, 1H NMR, UV-Vis., ESR and DART-MS) and other analytical methods. IR spectral studies indicate the binding sites of the ligand with the metal ion. Molar conductance data and magnetic susceptibility measurements provide evidence for monomeric and neutral nature of the complexes. The X band ESR spectrum of the Cu(II) complex at 300 and 77 K was recorded. The electrochemical behaviour of the complexes in MeCN at 298 K was studied. Thermal studies of the ligand and its complexes show the presence of coordinated water in the complexes. The grain size of the complex was calculated by Scherrer formula using powder XRD. The surface morphology of the complexes was studied using SEM. The in vitro biological screening of the ligand and its complexes were tested against bacterial species S. aureus, E. coli, K. pneumoniae, P. vulgaris and P. aeruginosa and fungal species A. niger, R. stolonifer, A. flavus, R. bataicola and C. albicans. The DNA binding and cleavage activity of the ligand and its complexes were studied. Super oxide dismutase (SOD) activities of the ligand and its complexes have also been measured. © 2013 Elsevier B.V. All rights reserved.

Muthuraman G.,Presidency College at Chennai | Sasikala S.,Presidency College at Chennai
Journal of Industrial and Engineering Chemistry | Year: 2014

The ability of three plant materials, seeds such as Moringa oleifera, Strychnos potatorum and Phaseolus vulgaris, to act as natural coagulants was tested using synthetic turbid water formulated to resemble the drinking water. An improved and alternative method for the extraction of the active coagulant agent M. oleifera, S. potatorum, P. vulgaris seeds was developed and compared with the conventional water extraction method. In the new method the seeds were extracted using different solvents of NaCl and NaOH to extract the active coagulant agent from natural coagulants. In addition, ultrasound was investigated as a potential method to assist the extraction process. Batch coagulation experiments were conducted to evaluate the performance of the extracted coagulant achieved through various schemes. The optimum turbidity removal at different values of initial synthetic wastewater turbidity from 100 to 500 NTU was investigated. Sodium chloride at 0.5. M was found to provide a high turbidity removal of >99% compared to NaOH and distilled water extract. Among these three coagulant M. oleifera seed extracts is the highest performance in turbidity removal. The optimum coagulant dosage showed the coagulation with blended coagulant M. oleifera, S. potatorum and P. vulgaris. The study was carried out for initial turbidity of the sample such as 100 NTU (low), 250 NTU (medium) and 500 NTU (high). For the natural coagulant dosage was found to be 250-1000. mg/L respectively. It was found that the percentage of removal is highest in M. oleifera. © 2013.

Gnanam S.,Presidency College at Chennai | Rajendran V.,Presidency College at Chennai
Journal of Sol-Gel Science and Technology | Year: 2011

Nanocrystalline cubic fluorite/bixbyite CeO2 or α-Mn 2O3 has been successfully synthesized by using methanol as a solvent via sol-gel method calcined at 400°C. The obtained products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-vis absorption and Photoluminescence (PL) spectroscopy. TEM reveals that the as-synthesized ultra-fine samples consist of elliptical/spherical and sheet-like morphology of crystalline particles of 8/30 nm, which are weakly aggregated. Optical absorbance spectra reveal that the absorption of ceria in the UV region originates from the charge- transfer transition between the O2- (2p) and Ce4+ (4f) orbit in CeO2. However, α-Mn2O3 nanostructures with nearly pure band gap emission should be of importance for their applications as UV emitters. © 2010 Springer Science+Business Media, LLC.

Gnanam S.,Presidency College at Chennai | Rajendran V.,Presidency College at Chennai
Journal of Sol-Gel Science and Technology | Year: 2010

Tin oxide (SnO2) nanoparticles were synthesized by the reaction of SnCl4•5H2O in methanol, ethanol and water via sol-gel method. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared, Scanning electron microscopy and Transmission electron microscopy. The optical properties of the as-prepared samples were investigated. The XRD analysis showed well crystallized tetragonal SnO 2 can be obtained and the crystal sizes were 3.9, 4.5 and 5 nm for the sample calcined at 400 °C for 2 h. It was found that solvents played important roles in the particle size effect of nanocrystalline SnO2. © 2009 Springer Science+Business Media, LLC.

Discover hidden collaborations