Tirunelveli, India
Tirunelveli, India

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Chithra Lekha P.,Manonmaniam Sundaranar University | Subramanian S.,The MDT Hindu College | Philip J.,Cochin University of Science and Technology | Pathinettam Padiyan D.,Manonmaniam Sundaranar University
Physica B: Condensed Matter | Year: 2010

Polyaniline (PAni) doped with dodeca tungstophosphoric acid (12TPA) nanomaterials prepared by interfacial polymerization are characterised via UVvis spectroscopy, X-ray diffraction, thermogravimetry and ac impedance analysis. From the X-ray diffraction pattern, the crystallite size of the nanomaterials is found to be around 10-50 nm. The ac impedance studies on these materials in the temperature range 300-398 K show that the conductivity in PAni is due to the hopping of polarons following correlated barrier hopping model whereas in PAni doped with 12TPA (P12TPA) it is due to the tunneling of large polarons. It gives an understanding on the role of thermal annealing over the conductivity of the P12TPA, which arises from the presence of hydroxyl groups and is also evident from the thermogram. The humidity sensing behaviour of the nanomaterial elucidates the P12TPA as a good humidity sensor. The results of optical, structural and thermal analysis illustrate that PAni and 12TPA are not simply blended or mixed up, but a strong interaction is there between the polymer backbone and the polyanion. © 2010 Elsevier B.V. All rights reserved.

Subramanian S.,The Mdt Hindu College | Balaji M.,Manonmaniam Sundaranar University | Chithra Lekha P.,Manonmaniam Sundaranar University | Asokan K.,Inter University Accelerator Center | And 4 more authors.
Current Applied Physics | Year: 2010

Sb2S3 thin films prepared by electrodeposition on indium tin oxide coated glass substrate were irradiated with 150 MeV Ni11+ ions for various fluence in the range of 1011-1013 ions/cm2. The modifications in the structure, surface morphology and optical properties have been studied as a function of ion fluence. X-ray diffraction (XRD) analysis indicates a shift in the (2 4 0) peak position towards lower diffraction angle and a decrease in grain size with increase in ion fluence. Presence of microcracks due to irradiation induced grain splitting effect has been observed from the SEM micrograph at higher ion fluence. The optical absorbance spectrum revealed a shift in the fundamental absorption edge and the band gap energy increased from a value of 1.63 eV for as-deposited films to 1.80 eV for the films irradiated with 1013 ions/cm2. © 2010 Elsevier B.V. All rights reserved.

Chithra lekha P.,Manonmaniam Sundaranar University | Balaji M.,Manonmaniam Sundaranar University | Subramanian S.,The MDT Hindu College | Pathinettam Padiyan D.,Manonmaniam Sundaranar University
Current Applied Physics | Year: 2010

The polyoxomolybdates encapsulated PAni hybrid materials are prepared by interfacial polymerisation. In P12MPA, the crystal structure of 12MPA is not modified on doping with PAni. However, P11MPA have the polycrystallinity due to the presence of vanadium in the dopant molecule. Though, the hybrids prepared by interfacial polymerisation are in emaraldine salt form, there is a blue shift in the absorption spectra due to dopant induced decrease in conjugation length and over-oxidation. Interfacially polymerised PAniPOM hybrid materials are exposed with various concentrations of vapours of different volatile organic compounds (VOC) such as acetone, methanol, chloroform and carbon tetrachloride. The oxidising VOCs like acetone and methanol on exposure to PAni decrease the resistivity by hydrogen bonding with the redox cites of the polymer. Among these two, the sensitivity towards acetone is more in PAni and its hybrids which can be linked with the vapour pressure of the analyte. Due to the weak acidic characteristics of chlorinated hydrocarbons which are reducing vapours, the resistivity of PAni and its hybrids increases on exposure to chloroform and CCl4. Here, the chlorinated hydrocarbons interact with the redox sites of PAni and reduce it to base form. Bridging of polymer chains is also proposed for the reduction of conductivity on exposure to the analyte. The sensitivity is higher for the reducing analytes than that of the oxidising one. © 2009 Elsevier B.V. All rights reserved.

Subramanian S.,The Mdt Hindu College | Chithra lekha P.,Manonmaniam Sundaranar University | Pathinettam Padiyan D.,Manonmaniam Sundaranar University
Physica B: Condensed Matter | Year: 2010

Thin films of polyaniline (PAni) that included Sb2S3 are prepared at three different concentrations of PAni using electrodeposition method. X-ray diffraction pattern indicates the polycrystalline nature of all the films and it is found that crystallite size increases with the increase in concentration of PAni. The morphology of the doped films changes due to the addition of PAni. The dc conductivity of samples with different concentrations of PAni has been investigated as a function of temperature and it follows three-dimensional variable range hopping. PAni doped films show a shift in the FTIR peaks at 1024 and 1376 cm-1. Optical measurements show that the absorption edge red shifts on increasing the doping concentration. © 2009 Elsevier B.V. All rights reserved.

Chithra lekha P.,Manonmaniam Sundaranar University | Subramanian S.,The MDT Hindu College | Yi J.,Sungkyunkwan University | Dhanuskodi S.,Bharathidasan University | Pathinettam Padiyan D.,Manonmaniam Sundaranar University
Materials Chemistry and Physics | Year: 2010

The electrochemically prepared polyaniline-12-molybdophosphoric acid (P12MPA) thin films in conducting emeraldine salt form of polyaniline (PAni) matrix is verified by the presence of redox peaks in the UV-vis spectra for different dopant concentrations. The optical band gap energy in these films is dopant concentration dependant and tunable. From the FTIR spectra, it is evidenced that, the characteristic peaks of PAni is present in P12MPA thus there is only conformational change due to the inclusion of molybdophosphoric acid (12MPA) in the polymer matrix. The amorphous nature of the film is proved from the XRD. XPS peaks of PAni and P12MPA thin films have shown the evidence for the presence of quinoid imine, benzenoid amine and the polaronic nitrogen and the oxidation level is quantitatively analysed. P12MPA has the oxidation level of around 51% which matches with that of protonated emeraldine form. Due to the inclusion of 12MPA, in addition to para coupling of the monomer, ortho coupling also takes place. Impedance analysis shows the role of temperature in crosslinking of polymer chain and dopant anions. The high response of P12MPA (64.8%) towards acetone vapor provides evidence for improved sensing behaviour of the doped polymer. © 2010 Elsevier B.V. All rights reserved.

Srinivas Y.,Manonmaniam Sundaranar University | Muthuraj D.,The Mdt Hindu College | Oliver D.H.,Manonmaniam Sundaranar University | Stanley Raj A.,Manonmaniam Sundaranar University | Chandrasekar N.,Manonmaniam Sundaranar University
Environmental Earth Sciences | Year: 2013

Coastal aquifers can become polluted due to natural and human activities, such as intrusion of saline water, discharge of effluents in industrial areas and chemical weathering of natural geological deposits. The present study is aimed mainly at understanding the geophysical and chemical characteristics of groundwater near Tuticorin, Tamilnadu, India by studying the electrical resistivity distribution of the subsurface groundwater by applying the Schlumberger vertical electrical sounding (VES) technique followed by chemical analysis of water samples. A total of 20 VES soundings were carried out to understand the resistivity distribution of the area and 21 water samples were collected to analyze the chemical quality. The interpretation and analysis of the results have identified different hydrogeologic behaviors, a highly saline coastal aquifer and freshwater locations. The results obtained from geophysical and geochemical sampling are in good agreement with each other. The approach shows the efficacy of the combination of geophysical and geochemical methods to map groundwater contamination zones in the study area. © 2013 Springer-Verlag Berlin Heidelberg.

Muthuraj D.,The Mdt Hindu College | Srinivas Y.,Manonmaniam Sundaranar University | Chandrasekar N.,Manonmaniam Sundaranar University
International Journal of Applied Environmental Sciences | Year: 2010

An electrical resisitivity survey consisting of vertical electrical soundings (VES) was carried out in order to delineate potential ground water locations near Tirunelveli, Tamilnadu, India. Accordingly an investigation employing VES was conducted using the Schlumberger electrode configuration. One-dimensional (1D) interpretation of the sounding data was made primarily using the curve matching method and 2D inverse modeling was carried out on the resistivity data using subsurface electrical imaging computer software packages to obtain better estimation of resistivities and thicknesses of the subsurface layers. The interpreted results were used to delineate the potential ground water aquifers. The interpretation of the VES data indicates the presence of three, four subsurface layers, the top layer is thin soil cover and the second layer is weathered or semi-weathered hard rock and the third layer is highly resistive bedrock. A fracture zone is interpreted at a depth of about l0meters and is correlated with available geological, hydrogeological and geophysical information including bore well lithology. The observed data and the interpreted data is presented here as a case study. © Research India Publications.

Annalakshmi T.,St Xaviers College | Syed Ali Fathima K.M.,St Xaviers College | Xavier Innocent B.,St Xaviers College | Sivagurunathan A.,The Mdt Hindu College
International Journal of Research in Ayurveda and Pharmacy | Year: 2013

Outbreak of disease is an important limiting factor in aquaculture. Incorporation of herbal immunostimulants in diet is one of the widely followed methods to improve the general resistance in fish. The present experiment was carried out to evaluate the Immunostimulatory potential of the medicinal herb Phyllanthus amarus in fish. The experiment was carried out in two sets. In experiment-I, one group of Labeo rohita was fed with control diet ('C' diet) and the other group was fed with Phyllanthus amarus incorporated diet ('P' diet) for 14 days and the haematological parameters were analysed on 1st, 3rd, 7th and 14th day of the experiment. Significant increase in Total Erythrocyte Count (TEC), Haemoglobin (Hb g%), Total Leucocyte Count (TLC), lymphocytes, monocytes and neutrophils were observed in 'P' diet fed fishes with increase in the duration of the experiment. As there is positive response in the first experiment hence experiment-II was carried out. In experiment-II, One group of Labeo rohita were fed with 'C' diet and other group received 'P' diet for 14 days, post-infected with Aeromonas hydrophila and haematological parameters were analyzed on 1st, 3rd, 7th & 14th days after infection. Significant increase in TEC, Hb, TLC, lymphocytes and a steady population of monocytes and neutrophils were observed in 'P' diet fed fishes. On the other hand basophils and eosinophil count exhibited a fluctuating trend. Thus dietary incorporation of Phyllanthus amarus helps to improve the general health and resistance of the fish. © 2010 IJRAP.

Sivagurunathan A.,The Mdt Hindu College | Xavier Innocent B.,St Xaviers College | Muthu Lakshmi S.,The Mdt Hindu College
Journal of Applied Pharmaceutical Science | Year: 2012

The present study was carried out to evaluate the immunostimulant potential of Nelumbo nucifera (Lotus). Formulated diets with different concentrations of ethanolic extract of N.nucifera (D1=0%, D2=1% and D3=2%) were fed to Cirrhinus mrigala for 40 days, the Specific Growth Rate (SGR) and Feed Conversion Ratio (FCR) were calculated significant increase was observed in SGR &FCR. Then the experimental fishes were infected with Pseudomonas aeruginosa and after 5 days the haematological parameters like Total Erythrocyte count (TEC), Haemoglobin (Hb), Total leucocyte count (TLC), Differential leucocyte count (DLC), serum total protein, serum albumin and globulin levels were analyzed. The TEC, Hb, TLC, Lymphocytes and monocyte counts increased significantly in D3 diet fed fishes. Highly significant increase was observed in serum total protein and albumin levels only. Globulin levels remain unchanged. Basophil and Eosinophil counts decreased significantly. Thus N.nucifera in fish feed preparations may be included as growth promoter and immunostimulator.

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