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Kottayam, India

Joseph P.V.,Kuriakose Elias College | Jacob C.,Alphonsa College
Asian Journal of Chemistry | Year: 2010

A short term, baseline study was undertaken to determine the occurrence of microbial pollution in the Pennar river. Four stations were selected for study on the basis of land use pattern. Bacteriological, fungal and algal examinations were made and the results obtained showed that 8 species of bacteria isolated were opportunistic pathogens and total coliform count ranged from 460-2400/100 mL, thus making the water unsafe to drink unless treated properly. Fecal pollution from non human and human source is one of the major factors that contribute to the degradation of water quality and that restrict its use. Four fungal species were identified which are also opportunistic pathogens. In the present study about 36 different genera comprising 61 species of algae were idetified. High pollution tolerant species like Scenedesmus. Coelastrum, Oscillatoria, Nitzchia paella, Ankistrodesmus, Anabaena, Synedra and Navicula were present in different sites of Pennar river especially in the site I which is highly populated. High socioanthropological activities, clogging of water body due to weeds and agricultural practices in the basins were identified as a contributory factors to the situation. Source


Mahalakshmi V.,Smart Materials Analytic Research and Technology SMART Laboratory | Lincy A.,Smart Materials Analytic Research and Technology SMART Laboratory | Thomas J.,Kuriakose Elias College | Saban K.V.,St Aloysius College
Optik | Year: 2015

Crystals of diaqua maleatocalcium (II) (CaC4H2O4·2H2O) have been grown by the controlled diffusion of ionic species in inert hydrosilica gel. The single crystal X-ray diffraction studies reveal that the crystal belongs to orthorhombic system with non-centrosymmetric space group P212121. The unit cell parameters are a = 6.849(5) Å, b = 8.665(5) Å, c = 11.002(5) Å and α = β = γ = 90.000(5)°. The functional groups present in the compound are identified from the FTIR spectrum. Thermogravimetric studies are performed to explore the thermal stability and decomposition pattern of the material. The UV - vis - NIR studies indicate wide transparency window, a befitting material characteristic for optoelectronic applications. The optical band gap of the material was estimated using diffuse reflectance spectroscopy. The second harmonic generation (SHG) efficiency possessed by the crystal is revealed by the Kurtz and Perry powder test. © 2015 Elsevier GmbH. Source


Thomas A.K.,Smart Materials Analytical Research and Technology SMART Laboratory | Abraham K.,Smart Materials Analytical Research and Technology SMART Laboratory | Thomas J.,Kuriakose Elias College | Saban K.V.,Mary Matha Arts and Science College
Ceramics International | Year: 2015

Abstract The effect of doping the A site (Ca) with La and B site (Ti) with Nb, on the grain formation, crystallographic structure, electrical properties and dielectric behaviour of CaCu3Ti4O12 is investigated over wide ranges of temperature (27-150°C) and frequency (50 Hz to 5 MHz). Microstructure investigation of the cast compound, Ca(1-3x)La2xCu3Ti(4-5x)Nb4xO12 (x=0, 0.02 and 0.04), using Scanning Electron Microscopy (SEM) showed that co-doping would result in grain growth inhibition. Rietveld refinement of the powder diffraction data confirmed a cubic, single phase structure with space group Im3. The steady increase in the lattice volume with increasing dopant concentration confirms the incorporation of the bigger dopant molecules in the lattice. Dielectric studies using HIOKI 3552-50 LCR Hi-Tester show that the room temperature dielectric constant would considerably increase due to co-doping. Impedance spectroscopic studies reveal that the compound is electrically heterogeneous, with semi conductive grain interior and insulating grain boundaries. Doping resulted in a decrease in grain boundary resistance and consequent increase in dielectric loss at low frequency. The dielectric behaviour of compound is explained on the basis of the Internal Barrier Layer Capacitance (IBLC) model. © 2015 Elsevier Ltd and Techna Group S.r.l. Source


Lincy A.,Smart Materials Analytic Research and Technology SMART Laboratory | Mahalakshmi V.,Smart Materials Analytic Research and Technology SMART Laboratory | Thomas J.,Kuriakose Elias College | Raghavaiah P.,University of Hyderabad | Saban K.V.,St Aloysius College
Optik | Year: 2016

Single crystals of a new nonlinear optical material, triaquatrismalonatodicerium (III) dihydrate ([3H2O(C3H2O4)3 Ce2]·2H2O), have been grown using gel aided solution growth technique. The functional groups present in the crystal are identified using FTIR spectrum. X-ray diffraction studies on single crystals showed that the compound crystallizes in the monoclinic system with a non centrosymmetric space group P21 with unit cell dimensions a = 7.6795(5)Å, b = 12.9648(7)Å, c = 8.9545(5)Å, α = γ = 90°, β = 101.380(6)°. Thermogravimetric studies reveal the thermal stability and decomposition pattern of the material. The UV - vis spectrum indicates excellent transmittance in the entire visible region. Optical band gap energy of the crystal was evaluated from the diffused reflectance spectrum (DRS). Photoluminescence spectroscopy throws light on the optical emission properties. Excellent second harmonic generation (SHG) efficiency of the crystal was confirmed by Kurtz and Perry powder test. © 2015 Elsevier GmbH. Source


Vellanikaran J.J.,Kuriakose Elias College | Thomas A.P.,Kerala University
Asian Journal of Microbiology, Biotechnology and Environmental Sciences | Year: 2012

Mosquito menace in rural and urban India has reached alarming proportions. Improper urban development has compounded the problem. Extensive use of synthetic insecticides during the last few decades have resulted in environmental hazards and led to the development of physiological resistance in major vector species. Aedes aegypti is seen to transmit Dengue fever. From a selected twelve plant species of Umbelliferae family, extracts of five could induce significant mortality of A. aegypti larvae. Differential larvicidal activity was seen for various solvent extracts and both Hydrocotyle rotundifolia and Eryngium foetidum were found lethal to the larvae , the former was more effective. Synergic effect was observed when the crude extracts of H. rotundifolia and E. foetidum were used together. These two species are potential sources for larvicidal phytochemicals which may be used in mosquito control and eradication of Dengue fever. Crude extracts of three species - Ferula assa, Foetida, E. foetidum and H. rotundifolia exhibited potential larvicidal action. Development of safe biocides in future, may be done by isolation of the active principles from the crude extracts of Umbelliferae family. © Global Science Publications. Source

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