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Item Scopus(1993)Item CONDUCTION STUDIES ON EUROPIUM OXIDE THIN FILMS (Article)(Wiley, 1993-01-16) Meena, P; Balasubramanian, C; Narayandass Sa, K; Mangalaraj, DConduction studies are carried out on Eu2O3 thin film capacitors. From the ac conduction studies the dielectric constant is found to decrease with increase of frequency (< 1 MHz), but at very high frequency (> 1 MHz) it is found to increase. The ac conductance is found to be proportional to f at low frequencies, whereas a square-law dependence is observed at higher frequencies. The activation energy decreases with increase of frequency and increases with increase of temperature. The dc conduction studies reveal a space-charge limited conduction in this film. The density of free electrons, the density of trapped electrons, and the mobility of free electrons at different temperatures are calculated and the results are discussed.Item Scopus(1998)Item NUMERICAL EVALUATION OF TRICHOME CHARACTERS IN CERTAIN MEMBERS OF ASTERACEAE(Phytomorphology: An International Journal of Plant Morphology, 1998) Sasikala, K; Narayanan, RTrichome characters of vegetative and floral parts of nine taxa (considered as an OTU) were numerically analysed. Stomatal characters of these genera were either anomocytic or anisocytic. WPGM was employed for cluster analysis. Phenetic affinities between the OTUs were established on the basis of dendrograms. Present study shows that the trichome characters will be taxonomically significant at the level of the genus rather than at higher levels of hierarchy.Item Scopus(2003)Item UTILIZATION OF VARIOUS AGRICULTURAL WASTES FOR ACTIVATED CARBON PREPARATION AND APPLICATION FOR THE REMOVAL OF DYES AND METAL IONS FROM AQUEOUS SOLUTIONS(Elsevier, 2003-03) Kadirvelu, K; Kavipriya, M; Karthika, C; Radhika, M; Vennilamani, N; Pattabhi, SActivated carbons were prepared from the agricultural solid wastes, silk cotton hull, coconut tree sawdust, sago waste, maize cob and banana pith and used to eliminate heavy metals and dyes from aqueous solution. Adsorption of all dyes and metal ions required a very short time and gave quantitative removal. Experimental results show all carbons were effective for the removal of pollutants from water. Since all agricultural solid wastes used in this investigation are freely, abundantly and locally available, the resulting carbons are expected to be economically viable for wastewater treatment.Item MERCURY (II) ADSORPTION BY ACTIVATED CARBON MADE FROM SAGO WASTE(Elsevier, 2004) Kadirvelu, K; Kavipriya, M; Karthika, C; Vennilamani, N; Pattabhi, SThe preparation of activated carbon (AC) from sago industry waste is a promising way to produce a useful adsorbent for Hg (II) removal, as well as dispose of sago industry waste. The AC was prepared using sago industry waste with H2SO4 and (NH4)2S2O8 and physico-chemical properties of AC were investigated. Adsorptive removal of mercury (II) from aqueous solution onto AC prepared from sago industry waste has been studied under varying conditions of agitation time, metal ion concentration, adsorbent dose, particle size and pH to assess the kinetic and equilibrium parameters. Adsorption equilibrium was obtained in 105 min for 20 mg l−1 and 120 min for 30, 40, and 50 mg l−1 Hg (II) concentrations. The Langmuir and Freundlich equilibrium isotherm models were found to provide an excellent fitting of the adsorption data, with r2 0.9999 and 0.9839, respectively. The adsorption capacity of Hg (II) (Qo) obtained from the Langmuir equilibrium isotherm model was found to be 55.6 mg g−1 at pH 5.0 for the particle size range of 125–250 μm. The percent removal increased with an increase in pH from 2 to 10. This adsorbent was found to be effective and economically attractive.Item REMOVAL OF METHYLENE BLUE FROM AQUEOUS SOLUTION BY ADSORPTION ON TO ACTIVATED CARBON(Indian Journal of Environmental Protection, 2004) Manickavasakam, K; Krishnan, S M; Sameena, Y; Vennilamani, N; Pattabhi, SThe adsporption capacity of the activated carbon prepared from Gulmohar tree fruits was evaluated by the removal of methylene blue from aqueous solution by adsorption under different conditions, such as agitation time, initial dye concentration, adsorbent dosage, particle size and pH. Desorption study was carried out to elucidate the mechanism of adsorption. The time required to attain equilibrium was found to be 45 and 60 min for 20, 40 and 60, 80 mg/L dye concentration, respectively. The adsorption followed a pseudo first order rate equation and the experimental data follows Freundlich and Langmuir isotherm models. The adsorption capacity was found to be 96.15 mg/g of Gulmohar tree fruit carbon (GTFC) at the pH of 6 ± 0.2 and at room temperature (30 ± 2 °C) for the particle size of 125-250 μm. The complete removal of the dye from 20 and 40 mg/L of aqueous solution was possible with 1.2 and 1.4 g of the activated carbon, respectively. The percent removal was increased with decrease in the particle size of the adsorbent. The influence of pH on dye removal was insignificant and the adsorbed dye could not recover in both acidic acid basic conditions.Item Scopus(2004)Item EVALUATION OF A COMPOSITE CORROSION INHIBITING ADMIXTURES AND ITS PERFORMANCE IN PORTLAND POZZOLANA CEMENT(Elsevier, 2004-08) Muralidharan, S; Saraswathy, V; Merlin Nima, S P; Palaniswamy, NThe effect of various inhibitive and complexing ions like hydroxide, citrate and stannate for the corrosion of steel in concrete was studied by weight loss measurements, potential–time behaviour studies, potentiodynamic polarisation studies and electrochemical impedance measurements. The salient features of these investigations were, in 100% PPC extract the passivity of steel was readily destroyed even in the presence of 10 000 ppm of chloride. However, in 100% PPC extracts containing inhibitive and complexing agents like hydroxide, citrate and stannate, the passivity of steel was maintained even in the presence of 30 000 ppm of chloride. The addition of inhibitive ions like hydroxide, citrate and stannate decreased the corrosion of steel in simulated concrete environments. Citrates, stannates and calcium oxide are very effective inhibitors for corrosion of steel in Portland pozzolana cement.Item THE INFLUENCE OF BENZOYL HYDRAZINE AND SOME OF ITS SUBSTITUENTS ON CORROSION INHIBITION OF CARBON STEEL IN SULPHURIC ACID SOLUTION(Emerald Publishing Limited, 2004-12-01) Gowrani, T; Yamuna, J; Parameswari, K; Chitra, S; Selvaraj, A; Subramania, AThe influence of synthesised benzoyl hydrazine and some of its substituents on the inhibition of corrosion of carbon steel in 1M sulphuric acid solution were investigated using weight loss, gasometric measurements, potentiodynamic polarisation studies and impedance measurements. Corrosion kinetic parameters clearly revealed the fact that the inhibition of corrosion of carbon steel by these compounds was under mixed control. The effect of temperature on the corrosion behaviour of carbon steel in 1M H2SO4 with optimum concentration of inhibitors was studied in the temperature range 40°‐60°C. The activation energy (Ea) and free energy of adsorption (ΔGads0) were determined for all the inhibitors. The adsorption of these compounds on the carbon steel surface from 1M H2SO4 was observed to obey the Langmuir adsorption isotherm relationship.Item Scopus(2005)Item ACTIVATED CARBON FROM AGRICULTURAL WASTE AS AN ADSORBENT: ADSORPTION OF (R.ORANGE 3R) DYE FROM AQUEOUS SOLUTION (Abstract Only)(Indian Journal of Environmental Protection, 2005-01) Sameena, Y; Thangmani, K S; Madhavakrishnan; Pattabhi, SActivated carbon (AC) prepared from silk cotton hull was used to remove textile dye (R. Orange 3R) from aqueous solution by adsorption under different conditions, such as agitation time, adsorbent dosage, pH and dye concentration. The time required to attain equilibrium was found to be 60 min for all the concentrations studied (5 to 20 mg/L). Adsorption followed both Langmuir and Fruendlich isotherms. The present removal was decreased with increase in pH. The adsorption capacity was found to be 27.54 mg/g of AC at a pH of 2 ± 0.2 at room temperature (30 ± 2°C) for the particle size of 125-250μm. Adsorption capacity was depend on pH of the solution, adsorbent dosage and initial dye concentration.Item UTILIZATION OF ACTIVATED CARBON PREPARED FROM INDUSTRIAL SOLID WASTE FOR THE REMOVAL OF CHROMIUM(VI) IONS FROM SYNTHETIC SOLUTION AND INDUSTRIAL EFFLUENT (PDF)(SAGE Publications, 2005-03) Vennilamani, N; Kadirvelu, K; Pattabhi, SActivated carbon (AC) prepared from sago waste was character-ized and used to remove chromium(VI) ions from aqueous solution andindustrial effluent by adsorption methods using various conditions of agitationtime, metal ion concentration, adsorbent dosage particle size and pH. Surfacemodification of the carbon adsorbent with a strong oxidizing agent like concen-trated H2SO4 generates more active adsorption sites on the solid surface andpores for metal ion adsorption.Adsorption of the metal ion required a very short time and led to quantitativeremoval. Both the Langmuir and Freundlich isotherm models could describe theadsorption data. The calculated values of Q0and b were 5.78 mg/g and 1.75 1/min,respectively. An effective adsorption capacity was noted for particle sizes in therange 125–250 μm at room temperature (30 ±2°C) and an initial pH of 2.0 ±0.2.The specific surface area of the activated carbon was determined and itsproperties studied by scanning electron microscopy (SEM) and Fourier transforminfrared spectroscopy (FT-IR). These studies revealed that AC prepared fromsago waste is suitable for the removal of Cr(VI) ions from both synthetic andindustrial effluents.Item ANTICORROSION PERFORMANCE OF SOME ARYLIDENE-5-PYRAZOLONES FOR MILD STEEL IN SULPHURIC ACID(Bulletin of Electrochemistry, 2005-05) Selvaraj, A; Sudha, K; Anuradha, R; Parameswari, K5-Pyrazolone and four of its 4-arylidene derivatives were synthesized from acetoacetic ester, hydrazine hydrate and aromatic aldehydes, and evaluated as corrosion inhibitors for mild steel by weight loss method, gasometry, polarization measurements and impedance studies. Piperonalidene pyrazolone showed the best results among all the compounds tested even at low concentrations. The compounds act as mixed type inhibitors and their adsorption on steel surface obeys the Langmuir isotherm. The effect of temperature on the corrosion behaviour of steel showed that the inhibition efficiency decreases with increase in temperature (303-333K). Ea and ΔG ads were determined. The synergistic effect due to I- ions on one of the aryldene pyrazolone has also been noted.Item EFFECT OF FORMAZANS ON THE CORROSION INHIBITION OF MILD STEEL IN 1M SULFURIC ACID(Bulletin of Electrochemistry, 2005-06) Selvaraj, A; Anuradha, R; Sudha, K; Subramanian, ChitraThe effect of formazans as a new class of corrosion inhibitors on the corrosion of mild steel in H2SO4 has been investigated by various techniques. The results obtained reveal that all the compounds gave a maximum inhibition efficiency of 98-99% at 0.5-10.0 mM concentrations of the inhibitors. Potentiodynamic polarization studies showed that the inhibition was under mixed control. Adsorption on the mild steel surface followed the Langmuir adsorption isotherm. Values of the activation and free energy of adsorption are presented.Item ACTIVATED CARBON FROM INDUSTRIAL SOLID WASTE AS AN ADSORBENT FOR THE REMOVAL OF RHODAMINE-B FROM AQUEOUS SOLUTION: KINETIC AND EQUILIBRIUM STUDIES(Elsevier, 2005-08) Kadirvelu, K; Karthika, C; Vennilamani, N; Pattabhi, SThe activated carbon was prepared using industrial solid waste called sago waste and physico-chemical properties of carbon were carried out to explore adsorption process. The effectiveness of carbon prepared from sago waste in adsorbing Rhodamine-B from aqueous solution has been studied as a function of agitation time, adsorbent dosage, initial dye concentration, pH and desorption. Adsorption equilibrium studies were carried out in order to optimize the experimental conditions. The adsorption of Rhodamine-B onto carbon followed second order kinetic model. Adsorption data were modeled using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacity Q0 was 16.12 mg g−1 at initial pH 5.7 for the particle size 125–250 μm. The equilibrium time was found to be 150 min for 10, 20 mg l−1 and 210 min for 30, 40 mg l−1 dye concentrations, respectively. A maximum removal of 91% was obtained at natural pH 5.7 for an adsorbent dose of 100 mg/50 ml of 10 mg l−1 dye concentration and 100% removal was obtained when the pH was increased to 7 for an adsorbent dose of 275 mg/50 ml of 20 mg l−1 dye concentration. Desorption studies were carried out in water medium by varying the pH from 2 to 10. Desorption studies were performed with dilute HCl and show that ion exchange is predominant dye adsorption mechanism. This adsorbent was found to be both effective and economically viable.Item RELATIONSHIP BETWEEN ORGANISATIONAL VALUE ADDITION AND ENVIRONMENTAL SUSTAINABILITY PERFORMANCE IN AN INDIAN PULP AND PAPER MANUFACTURING UNIT AND ITS SUPPLY CHAIN: A LONGITUDINAL CASE STUDY(Inderscience Enterprises Ltd, 2005-10-03) Arivalagan, A; Sudhakar, BOrganisations that improve 'value addition' by implementing several initiatives do not verify impact of these initiatives have on environment. The modern sustainability era, demands elimination of environmental impacts, i.e., a positive correlation is expected between value addition and environmental performance on long term basis. Many studies on Corporate Sustainability Management, based on the data at one point of time, did not examine above said relationship. This paper discusses the relationship between value addition and environmental sustainability using ten years data of an Indian Paper Mill. Analysis of the data reveals that there is a negative correlation between value addition and environmental sustainability over the ten-year period.Item SYNTHESIS AND COMPARATIVE STUDY OF THE INHIBITIVE PROPERTIES OF ISOMERIC SCHIFF BASES AND ITS CYCLISATION PRODUCTS(Journal of Corrosion Science and Engineering, 2006) Thamaraiselvi, N; Parameswari, K; Chitra, S; Selvaraj, AThe corrosion behaviour of mild steel in 1M sulphuric acid solution and its inhibition by Schiff bases and thiazolidinones was studied using weight loss method at various temperatures (303-333K), by electrochemical and non - electrochemical techniques. The percentage inhibition efficiency of the inhibitors increased with increase in inhibitor concentration. Potentiodynamic polarization studies revealed that though the Schiff bases and thiazolidinones act as mixed type inhibitors they are slightly anodic in nature. Adsorption of these inhibitors on the mild steel surface followed the Langmuir adsorption isotherm. The thermodynamic parameters such as activation energy (Ea) and free energy of adsorption (ΔG°ads) were calculated. The synergistic effect of halide ions on the inhibition efficiency of thiazolidinones was also studied.Item BIODEGRADATION OF LIGNOCELLULOSIC COIR PITH BY USING FUNGAL FORMS(EM International, 2006) Vinodhini, S; Padma Devi, S N; Padma, SrinivasanThe present study deals with degradation of coir poll by Humicola sp. Trichoderma viride and Aspergillus terreus. The lignin, cellulose, organic carbon content and evolution of carbon-di-oxide were estimated in pith degraded aad non-degraded coir pith. The content of lignin and cellulose were found to be low in lignin and cellulose during different period of biodegradation.