n) 2012 - 17 Documents
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Item IN VITRO ANTIBACTERIAL ACTIVITY OF HIBISCUS ROSA–SINENSIS FLOWER EXTRACT AGAINST HUMAN PATHOGENS (Article)(Elsevier, 2012-05) Ruban, P; Gajalakshmi, KTo access the in vitro antibacterial activity of Hibiscus rosa–sinensis H. rosa-sinensis) flower extract against human pathogens.Item SYNTHESIS AND CHARACTERIZATION OF POLYANILINE/MNWO4 NANOCOMPOSITES AS ELECTRODES FOR PSEUDOCAPACITORS (Article)(Elsevier, 2012-03-15) Saranya, S; Kalai Selvan, R; Priyadharsini, NPolyaniline (PAni)/MnWO4 nanocomposite was successfully synthesized by in situ polymerization method under ultrasonication and the MnWO4 was prepared by surfactant assisted ultrasonication method. The thermal stability of PAni was determined by TG/DTA (Thermo Gravimetric/ Differential thermal analysis). The structural and morphological features of PAni, MnWO4 and PAni/MnWO4 composite was analyzed using Fourier transform infrared spectrometry, X-ray diffraction (XRD), scanning electron microscope (SEM) and Transmission electron microscope (TEM) images. The electro-chemical properties of PAni, MnWO4 and its composites with different weight percentage of MnWO4 loading were studied through cyclic voltammetry (CV) for the application of supercapacitors as active electrode materials. From the cyclic voltammogram, 50% of MnWO4 impregnated PAni showed a high specific capacitance (SC) of 481 F/g than their individual counterparts of PAni (396 F/g) and MnWO4 (18 F/g). The galvanostatic charge–discharge studies indicate the in situ polymerized composite shows greater specific capacitance (475 F/g) than the physical mixture (346 F/g) at a constant discharge current of 1 mA/cm2 with reasonable cycling stability. The charge transfer resistance (Rct) of PAni/MnWO4 composite (22 ohm) was calculated using electrochemical impedance spectroscopy (EIS) and compared with its physical mixture (58 ohm).Item SYNTHESIS OF INDIUM OXIDE CUBIC CRYSTALS BY MODIFIED HYDROTHERMAL ROUTE FOR APPLICATION IN ROOM TEMPERATURE FLEXIBLE ETHANOL SENSORS (Article)(Elsevier, 2012-03-15) Seetha, M; Meena, P; Mangalaraj, D; Yoshitake, Masuda; Senthil, KIndium oxide cubic crystals were prepared by using hexamethylenetetramine and indium chloride without the addition of any structure directing agents. The chemical route followed in the present work was a modified hydrothermal synthesis. The average crystallite size of the prepared cubes was found to be 40 nm. A blue emission at 418 nm was observed at room temperature when the sample was excited with a 380 nm Xenon lamp. This emission due to oxygen vacancies made the material suitable for gas sensing applications. The synthesized material was made as a composite film with polyvinyl alcohol which was more flexible than the films prepared on glass substrates. This flexible film was used as a sensing element and tested with ethanol vapours at room temperature. The film showed fast response as well as recovery to ethanol vapours with a sensor response of about 1.4 for 100 ppm of the gas.Item INFLUENCE OF COPPER ON THE MAGNETIC PROPERTIES OF COBALT FERRITE NANO PARTICLES (Article)(Elsevier, 2012-08) Balavijayalakshmi, J; Suriyanarayanan, N; Jayapraksah, RCopper substituted cobalt ferrite nano particles Co(1 − x)CuxFe2O4 (where x = 0, 0.2, 0.4, 0.6, 0.8, 1) are successfully synthesized using co-precipitation method and samples are sintered at 900 °C. The average nano crystalline sizes are found to be in the range of 37–52 nm. As the copper concentration increases, the magnetization of the octahedral sites and hence the net magnetization decreases. It is also observed that the saturation magnetization (Ms), remanent magnetization (Mr) and coercivity (Hc) decrease with increase in copper substitution. The frequency of the absorption band around 600 cm− 1 is shifted to a lower value. Plates and sponge like surface morphology of copper mixed ferrites are studied.Item PHARMACOGNOSTICAL, PHYTOCHEMICAL AND HEAVY METAL STUDIES ON AN ETHNO MEDICINAL PLANT-CORALLOCARPUS EPIGAEUS (ROTTL. &WILD.) CLARKE (Article)(International Journal of Pharmacognosy and Phytochemical Research, 2012) Umadevi, U; Kamalam, MLeaf, stem and tuber powder of Corallocarpus epigaeus were investigated for its pharmacognostical, phytochemical and heavy metal properties. Analytical value (loss on drying, total ash, acid insoluble ash, water soluble ash), solubility percentage, fluorescent analysis, extractive value using different solvents (petroleum ether, benzene, chloroform, acetone, ethanol, methanol and water), qualitative phytochemical analysis for detection of alkaloids, glycosides, flavonoids, tannins, phenols, proteins, amino acids, saponins and terpenoids. HPTLC studies of glycosides, flavonoids, phenolic compounds and heavy metal analysis for the accumulation of lead, copper and cadmium were studied. Analytical value, extractive value and solubility percentage exhibited marked difference between the leaf, stem and tuber powder of C. epigeaus. Fluorescent analysis does not differ among the selected plant parts under normal and UV light. Qualitative analysis of acetone and water extracts revealed the presence of secondary metabolites like alkaloids, glycosides, flavonoids, terpenoids, tannins, phenol, fats and fatty acids. HPTLC studies also confirmed the presence of glycosides, flavonoids and phenolic compounds. Heavy metals present in the plant parts are lower than the permissible level.Item IMPLICATIONS OF BACTERIAL ISOLATES IN HEAVY METAL TOLERANCE TO THE POLLUTED ENVIRONMENT (Article)(International Journal of Pharmaceutical Sciences Review and Research, 2012-09) Siva Ananthi, T.A; Meerabai, R STwo isolates namely, Bacillus sp. and Leclercia adecarboxylata were isolated from soil contaminated with wide range of heavy metals. Minimum inhibitory concentration (MIC) for both the isolates was at 2000 mg Pb L -1 and also exhibited high resistant to wide range of antibiotics.Item THE INHIBITION EFFECT OF THIAZINE COMPOUNDS TOWARDS THE CORROSION OF MILD STEEL IN SULPHURIC ACID MEDIA (Article)(Rasayan Journal of Chemistry, 2012) Hemapriya, V; Parameswari, K; Bharathy, GThe inhibition effect of thiazines (AT, CBT & NBT) on mild steel corrosion in 1M sulphuric acid (H2SO4) was investigated by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The result showed that corrosion rate was significantly decreased in presence of the inhibitors. The inhibiting action increases with the concentration of thiazine compounds to attain 99 % at 0.5mM of (AT). The increase in temperature leads to a decrease in the inhibition efficiency of the compounds in the temperature range 308-353K. Adsorption of thiazines on the mild steel surface in 1M H2SO4 obeyed the Langmuir adsorption isotherm. EIS measurements showed an increase in charge transfer resistance (Rct) with concentration. Potentiodynamic polarization study showed that the inhibitors act as mixed type, controlling both the anodic and cathodic reactions. Surface analysis by SEM confirmed the formation of adsorbed protective layer of the inhibitor on the steel surfaceItem LIPASE PRODUCTION BY ASPERGILLUS TERREUS USING COTTON SEED OIL AS CARBON SOURCE (Article)(Plant Archives, 2012) Sumathi, R; Meerabai, R SFungi isolated from soil were screened for exogenous lipolytic activity. The highest lipase activity was found in an isolate of Aspergillus terreus. Optimal cultural conditions influencing the growth and production of extra cellular lipase from this fungus was investigated. The lipase yield was maximum on day 5 of incubation when the medium was supplemented with maltose and cotton seed oil as sole carbon source and potassium nitrate as nitrogen source at pH 7 and at temperature of 40°C.Item INVESTIGATION OF BENZOTHIAZOLE DERIVATIVES AS CORROSION INHIBITORS FOR MILD STEEL (Article)(Portugaliae Electrochimica Acta, 2012) Parameswari, K; Chitra, S; Selvaraj, A; Brindha, S; Menaga, MThe influence of benzothiazole derivatives on corrosion inhibition of mild steel in 1 M H2SO4 was studied by weight loss, potentiodynamic polarization and AC-impedance techniques. The synergistic effect by the addition of halide ions had been studied. The experimental results showed that the inhibition efficiency increases with increasing inhibitor concentration, but decreases with increasing temperature; potentiodynamic polarization curves showed that benzothiazole derivatives acted as cathodic inhibitors in 1 M H2SO4. This was supported by the impedance measurements which showed a change in the charge transfer resistance and double layer capacitance, indicating adsorption of Benzothiazole derivatives on the mild steel surface. Atomic absorption spectroscopy studies showed that the inhibition efficiency increases with increasing inhibitor concentration.Item SYNTHESIS AND CHARACTERIZATION OF EPOXY–SILICONE–POLYTHIOPHENE INTERPENETRATING POLYMER NETWORK FOR CORROSION PROTECTION OF STEEL (Article)(Elsevier, 2012-12) Palraj, S; Selvaraj, M; Vidhya, M; Rajagopal, GPolymer alloys, particularly interpenetrating polymer networks (IPNs) exhibit excellent coating properties. Often combination of polymers result in IPNs with controlled morphologies and synergistic behavior. In this study, corrosion-resistant IPNs were prepared from immiscible resins (epoxy, silicone and thiophene) using a cross-linking agent and a catalyst. GPC, FTIR, NMR, TG, DTA and SEM studies used to fix the best performing IPN. Surface morphology studies using SEM confirm the incorporation of silicone and polythiophene in to the epoxy polymer to form homogeneously micro structured IPN. The heat-resistance of the IPN was determined as per ASTM 2485. The improved corrosion resistance of the IPN was evaluated by AC impedance measurements.