Browsing by Author "Subhashini, S"
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Item Acid Extracts of Ervatamia coronaria Leaves for Corrosion Inhibition of Mild Steel(2010) Subhashini, S; Rajalakshmi, RCorrosion inhibitors for acid cleaning processes are used to restrict dissolution of the base metal and decrease acid consumption and hydrogen gas evolution. Because of the toxic nature and high cost of some chemicals currently in use, it is necessary to develop environmentally acceptable and less expensive inhibitors. Natural products can be considered as a good source for this puipose. An evaluation of the effective performance of extract of Ervatamia coronaria leaves on the corrosion inhibition of mild steel in 1 M HCl and 0.5 M H2SO4 at ambient temperature has been made. Conventional weight loss and electrochemical measurements were used for the evaluation. Electrochemical studies reveal that the plant extracts act as mixed type inhibitors. The Etvatamia coronaria (Nandhiyavatai) leaves extracts yielded a maximum of 98 % in acid medium. Surface coverage values were tested graphically for suitable adsorption isotherm.Item Ambient Air Quality in the Area of Associated Cement Companies Limited Madukkarai, Tamilnadu: A Case Study(1998-04) Savithiri, V; Subhashini, SItem Antifungal Assay of Root Extract Fractionates of Clerodendrum Inerme (Linn,)(2015) Subhashini, SClerodendrum inerme is a medicinal plant reported to be used for the treabnent of skin diseases. Venereal infections, elephantiasis, asthma, topieal bums and rheiunatism. J'hc plant possesses high medicinal jxttcntial. Fractionation of ethanol extract of roots of Clerodendrum inerme was done attd antifungal activity of tlie fractions was assessed against microorganisms, Monascus ruber, Aspergillus Niger, Aspergillus fumigants and Candida albicans by disc diffusion inctliod. The ethanol extract showed antifungal activity against Monoscus ruber comparable to Standard clotrimazole.Item Chemical and Electrochemical Investigations of Wheat Bran Extract as Corrosion Inhibitor for Mild Steel in Acid Medium(2011-05) Jothi, R; Subhashini, SItem Chitosan Schiff base as eco-friendly inhibitor for mild steel corrosion in 1 M HCI(2016) Subhashini, SIn the present study, natural biopolymer chitosan was modified into its Schiff base derivative with salicylaldehyde by condensation method.' The prepared chitosan salicylaldehyde Schiff base was characterized using ultraviolet spectroscopy, fouriertransform infrared spectroscopy, 'scanning electron microscope and elemental analysis. Thermal analysis was also carried out to determine the thermal stability of . the derivative. To explore the corrosion inhibition performance of the chitosan Schiff base, weight loss, and electrochemical techniques were conducted. The inhibitor reduces the metallic corrosion by adsorbing on to the metal surface. The adsorption of chitosan Schiff base on mild steel surface in 1 M HCI followsTemkin isotherm model. Thermodynamic parameters of adsorption and corrosion process were calculated, which revealed the chemical nature of adsorption. SEM and energy dispersive X-ray spectroscopic analysis confirmed the formation of protective chitosan derivative layer oh the mild steel surface.Item Cocos Nucifera Shell as a Potential Inhibitor for Mild Steel Corrosion in Acidic Medium(2010) Subhashini, SThe effect of coconut {Cocos nucifera) shell extract obtained by destructive distillation, on the corrosion of mild steel in HiSO^ and HCl in the temperature range of 30-60° C was studied by weight loss method and electrochemical measurements. Results obtained reveal that the extract reduces the corrosion rate. The inhibition efficiency increases with an increase in the concentration of the extract and appreciable increase with increase in temperature. Experimental results were fitted into various adsorption isothenns. Activation energy and thermodynamic parameters were evaluated from temperature studies. Electrochemical measurements reveal that the extract behaves as a mixed type inhibitor. A suitable mechanism is also proposed.Item Copolymerization of Aniline and Crotonic Acid Using Various Surfactants in Aqueous Media(2013-05) Subbulakshmi, M; Subhashini, SItem Corrosion Inhibition Effect of Dicycloimine Hydrochloride (DCI) on Mild Steel in IM HCl(2010) Subhashini, S; Rajalakshmi, RAddition of corrosion inhibitors is one of the widely used methods to control corrosion. In the this work, an attempt has been made to explore the possibility of using dicycloimine hydrochloride (DCI) as an inhibitor on mild steel in 1 M HCl. Tlie inhibition efficiency uf DCI has been evaluated by conventional weight loss method and electrochemical polarization studies. Experimental results are fitted to various adsorption isotherms. Thermodynamic parameters have also been studied from temperature studies. The results reveal that DCI acts as an effective inhibitor (around 90% of IE) in HCl media.Item Corrosion Inhibition of Aqueous Extract of Cocos niicifera - Coconut Palm - Petiole Extract from Destructive Distillation for the Corrosion of Mild Steel in Acidic Medium(2010) Subhashini, SThe inhibitive effect and adsorption properties of petiole extract obtained from destructive distillation of cocos nucifera for the corrosion of mild steel in 0.5 M H2SO4 and 1 M HCl were investigated using mass loss, polarization and electrochemical impedance techniques of monitoring corrosion. The results obtained indicate that petiole extract of cocos nucifera behaves as good inhibitor for the corrosion of mild steel in 0.5 M H2SO4 and 1 M HCl. Activation energy of thermodynamic parameter was evaluated from temperature studies result. The adsorption of the inhibitor on mild steel surface was found to be spontaneous, endothermic and consistent with the assumptions of Langmuir adsorption isotherm. The electrochemical measurements reveal that the petiole extract behaved like mixed type inhibitor. Efforts are made to analyze the effectiveness of petiole extract of coconut palm in industrial processes.Item Corrosion Inhibition of Mild Steel by Water Soluble Poly (Vinyl Pyrrolidone - Aniline) in IM HCl(2010) Subhashini, S; Rajalakshmi, RThe present work reports the chemical oxidative synthesis of Polyaniline (PANI) in stable aqueous solution/dispersion form, using poly vinyl pyrrolidone (PVP) as an efficient steric stabilizer. This Poly (VinylPyrrolidone - aniline) water soluble composite used as corrosion inhibitor for mild steel in IM HCl at different concentrations. Weight loss, potenziodynamic polarization and electrochemical impedance spectroscopy measurements were employed. Impedance studies indicated an increase in charge transfer resistance and decrease in double layer capacitance with increase in inhibitor concentration. Potenziodynamic polarization study implies that the inhibitor acts as mixed type inhibitor. Maximum inhibition efficiency was witnessed with 0.2 % percentage of PVPA. The adsorption of the compounds on mild steel surface was found to obey Langmuir’s and 'I'emkin’s adsorption isotherm. The values of activation energy, free energy of adsorption, heat of adsorption, enthalpy of activation, entropy of activation were also calculated to elaborate the mechanism of corrosion inhibition.Item Corrosion Inhibition of Mild Steel in Acid Solution by 3,4,5-Trimethoxyphenyl-2-imidazolines(2010) Subhashini, SA heterocyclic imidazoline, 3,4,5-trimethoxyphenyl-2-imidazolines (TMP2I) was tested for its corrosion inhibition in 0.5 M H2SO4 and 1 M HCl using weight loss, Tafel polarisation and electrochemical impedance techniques. The re.sults show that the inhibition efficiency increases with the increase in concentration of TTVIP2I and the higher efficiency of about 98% is obtained in both the acid media at 20 ppm. The ad.sorption of TMP2I obeys Langmuir adsorption i.sotherm and occurs spontaneously. Cathodic and anodic polarization curves of mild steel in the presence of different concentrations of TMP2I at 30 °C reveal that it is a mixed type of inhibitor. Electrochemical impedance studies reveal that the system follows mixed mode of inhibition. The surface morphology of the mild steel specimens was evaluated using SEM imagesItem Corrosion inhibition, adsorption and thermodynamic properties of poly(vinyl alcohol-cysteine) in molar HCl(2014) Subhashini, SChemical synthesis of water soluble conducting polymer composite poly(vinyl alcoholcysteine) [PVAC] was carried out in oxalic acid medium using ammonium persulfate. The composite was characterized by UV, FTIR and SEM-EDX. The corrosion inhibition performance of PVAC on mild steel in molar hydrochloric acid solution was studied by weight loss and electrochemical methods. A maximum inhibition efficiency of 94% was observed in the presence of 0.6 wt% of the inhibitor. The influence of inhibitor concentration, solution temperature, and immersion time on the corrosion of mild steel has been investigated. Polarization measurements showed the mixed type inhibitive nature of the polymer composite. The results obtained from the different methods are in good agreement. The various kinetic and thermodynamic parameters of metal dissolution and composite adsorption processes were evaluated from the weight loss methods in order to elaborate the adsorption mechanism. Adsorption of inhibitor obeyed El-Awady adsorption isotherm. © 2014 Production and hosting by Elsevier B.V. on behalf of King Saud UniversityItem Corrosion Mitigating Effect of Cyamopsis Tetragonaloba Seed Extract on Mild Steel in Acid Medium(2010) Subhashini, S; Rajalakshmi, RThe role o f seed extract of Cyamopsis tetragonaloba on corrosion mitigation of mild steel in 1 M HCl has been investigated by weight loss method and potentiodynamic polarization technique. Maximum inhibition efficiency o f Cyamopsis tetragonaloba in 1 M HCl was found to be 92%. Experimental results were fitted into Langmuir and Temkin adsorption isotherm to study the process of inhibition. The potentiodynamic polarization results reveal that the seed extract behaved like mixed type inhibitor.Item Development of Self assembled Poly Carboxylate Chitosan Nanoparticles and their Application in Drug Delivery(2020-01) Sheeba Joy Bell, S; Subhashini, SItem Eco-friendly Chitosan Schiff bases for Enhanced Corrosion Resistance of Mild Steel in Acid Medium and Calcium Carbonate Scale Inhibition(2017-04) Menaka, R; Subhashini, SItem Eco-Friendly Corrosion Inhibitor from Poultry Waste for Mild Steel in Acid Medium(2008-04) Kowshalya, V, N; Subhashini, SItem Effect of Aliphatic Amines on the Corrosion of Aluminium in Acid Medium(1999-05) Bhuvaneswari, P; Subhashini, SItem Effectiveness of Behaviour Modification in Managing the Problem Behaviour and Social Interaction among Autistic Children(2021-01) Subhashini, S; Gayatridevi, SItem Effectiveness of Laughter Therapy in Managing Sleep Disturbances and Controlling Social – Media Addiction among Young Adults(2019-04) Subhashini, S; Sumathiral, KItem Evaluation of Chitosan Derivatives for the Delivery of Salicylic Acid(2017-04) Sathyapriya, P; Subhashini, S