PG and Research

Chennai, India

PG and Research

Chennai, India
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Jayaraj R.,PG and Research | Jeyasingh Thanaraj P.,PG and Research | Thillai Natarajan S.,PG and Research | Martin Deva Prasath P.,PG and Research
Journal of Chemical and Pharmaceutical Research | Year: 2011

Activated carbon (AC) prepared from marine algae was found to be a potential adsorbent for Congo red dye for removal from aqueous solution. The AC was prepared from marine algae Valoria bryopsis by treatment with conc. H 2SO 4. The surface area of the AC and its properties were studied by scanning electron microscopy (SEM). Adsorptive removal of Congo red from aqueous solution onto AC has been studied under varying conditions of agitation time, metal ion concentration, adsorbent dose and pH to assess the kinetic and equilibrium parameters. Adsorption equilibrium was found to be reached in 180 min for 5 to 25 mg/L of Congo red concentrations. The Langmuir and Freundlich isotherm models were found to provide an excellent fitting of the adsorption data. For the Freundlich isotherm, high r 2 values were obtained (0.8460 to 0.6992) for Congo red concentration of 10 to 60mg/L, which indicated favorable adsorption of Congo red onto marine algae carbon. The adsorption capacity of Congo red was found to be 97.77%. The percent removal increased with increase in pH from 1 to 5. This adsorbent was found to be effective and economically attractive.

Nishara Begum A.,PG and Research | Kalaiselvi C.R.,Erode Sengunthar Engineering College
International Journal of ChemTech Research | Year: 2014

The field of non-linear optics offers a host of fascinating phenomena of which some are eminently useful. The growth of single crystal has been made by growing pure KDP (Potassium Dihydrogen Phosphate) with dopants of Ni3+ and Mg2+ by slow evaporation solution growth technique and their desired change in properties were analysed. In FTIR spectrum, the frequency shifting confirms the incorporation of ions into the crystal lattice. The transmittance and absorbance spectrum for pure KDP and bimetallic KDP crystal is recorded by UV-Visible spectral analysis. The XRD pattern of both pure KDP and bimetallic KDP had three prominent peaks at (200), (112) and (321) and also change in the peak intensity was observed. The strength of the grown crystals was verified by Vicker's microhardness measurements. NLO property is studied by Kurtz method which confirms the second harmonic generation. Doping of KDP with Ni3+ and Mg2+ are the promising material for optical harmonic generation.

Kumar R.S.,PG and Research | Sudhagar P.,Hanyang University | Matheswaran P.,PG and Research | Sathyamoorthy R.,PG and Research | Kang Y.S.,Hanyang University
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2010

The surface modification of the ZnO seed layer by ultrasonic mediated rinsing (UMR) was realized as an efficient tool for growing highly branched hierarchical ZnO nanorods through multistage approach. The hierarchical ZnO nanostructure achieved through UMR approach was performed as the photoanodes in dye-sensitized solar cells (DSSCs). The DSSC based on the novel branched network resulted in energy conversion efficiency (η) of 1.1% (Jsc = 4.7 mA cm-2). The improved device performance was ascribed to the (a) high internal surface area for efficient dye adsorption, (b) rapid electron pathway for charge transport from ZnO to transparent conducting oxide (TCO) substrate and (c) producing random multiple scattering of the light within the hierarchical network leading to photon localization, thereby increasing the probability of the interaction between the photons and the dye molecules of the branched network. The beneficial effect of the UMR approach was distinguished by fabricating DSSCs based on randomly oriented ZnO nanorods prepared by conventional rinsing (CR), which offered lower conversion efficiency η = 0.7% (Jsc = 3.8 mA cm-2). The exploration of novel hierarchical ZnO nanorods grown in the present work by the low temperature solution growth techniques may pave way to bring out photoanode material on flexible substrates for the fast growing DSSCs devices. © 2010 Elsevier B.V. All rights reserved.

Saravana Kumar R.,PG and Research | Sathyamoorthy R.,PG and Research | Matheswaran P.,PG and Research | Sudhagar P.,Hanyang University | Kang Y.S.,Hanyang University
Journal of Alloys and Compounds | Year: 2010

We explore a facile route to prepare one-dimensional (1D) ZnO nanostructures including nanorods/nanospines on glass substrates by integrating inexpensive successive ionic layer adsorption and reaction (SILAR) and chemical bath deposition (CBD) methods. The effect of seed layer on the growth and morphology of the ZnO nanostructures was investigated. Accordingly, the surface modification of the seed layer prepared by SILAR was carried out by employing two different drying processes namely (a) allowing the hot substrate to cool for certain period of time before immersing in the ion-exchange bath, and (b) immediate immersion of the hot substrate into the ion-exchange bath. X-ray diffraction (XRD) analysis of the ZnO films revealed hexagonal wurtzite structure with preferential orientation along c-axis, while the scanning electron microscopy (SEM) revealed the dart-like and spherical shaped ZnO seed particles. ZnO nanostructures grown by CBD over the dart-like and spherical shaped ZnO seed particles resulted in the hierarchical and aligned ZnO nanospines/nanorods respectively. Room temperature photoluminescence (PL) study exhibited highly intense UV emission with weak visible emissions in the visible region. The growth mechanism and the role of seed layer morphology on the formation of ZnO nanostructures were discussed. © 2010 Elsevier B.V. All rights reserved.

Mageshwari K.,PG and Research | Mali S.S.,Shivaji University | Sathyamoorthy R.,PG and Research | Patil P.S.,Shivaji University
Powder Technology | Year: 2013

MgO nanoparticles were synthesized by template-free reflux condensation approach. XRD and FTIR confirmed the formation of single phase MgO exhibiting cubic crystal structure. SEM and TEM analysis revealed the formation of MgO nanoflakes. The optical band gap of MgO nanoparticles estimated from UV DRS was in the range 5.40-5.45. eV. PL spectra of MgO nanoparticles showed visible emissions due to the formation of defects in the band gap region of MgO. Synthesized MgO nanoparticles exhibited appreciable photocatalytic activity for the degradation of methyl orange and methylene blue dyes under UV light irradiation. Results demonstrated that the origin of photocatalytic activity in MgO arises due to the existence of high concentration of native defects on the surface of MgO.© 2013 Elsevier B.V.

Mageshwari K.,PG and Research | Mali S.S.,Shivaji University | Hemalatha T.,PG and Research | Sathyamoorthy R.,PG and Research | Patil P.S.,Shivaji University
Progress in Solid State Chemistry | Year: 2011

We report a facile, low-temperature soft solution route to synthesize copper sulfide (CuS) nanomaterials with different morphologies by reflux condensation method. CuS nanomaterials were synthesized without the assistance of additional surfactant or templates, and the influence of key synthetic parameters namely solvent medium and sulfur source on the final structure of CuS was comprehensively investigated. XRD pattern of the synthesized products revealed the formation of hexagonal structure of covellite CuS. SEM analysis showed that the CuS products synthesized in water were ball-like microspheres and the products prepared in ethanol were spherical shaped CuS nanocrystals, but those synthesized in ethylenediamine were flower-like CuS hierarchical network consisting of self-assembled nanoflakes as primary building units. DRS exhibited the characteristics broadband absorption of CuS in near-IR region. The optical band gap of the CuS nanocrystals was in the range between 2.35 eV and 2.81 eV, exhibiting considerable blue shift due to quantum size effects. Electrical resistivity measurements confirmed the semiconducting nature of CuS. On the basis of experimental results, the plausible formation mechanism of different CuS nanostructures was put forward and discussed briefly. © 2011 Elsevier Ltd. All rights reserved.

Dhanam M.,PG and Research | Kavitha B.,PG and Research | Velumani S.,CINVESTAV
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2010

Cu(In1-xAlx)Se2 [CIAS] thin films were prepared for the first time by successive ionic layer adsorption and reaction [SILAR] method with two different dipping cycles. The thickness of the films was measured by gravimetric technique. The structural, morphological, compositional, optical transition and electrical investigation of SILAR CIAS thin films with respect to two different dipping cycles have been discussed in this paper. © 2010 Elsevier B.V. All rights reserved.

Matheswaran P.,PG and Research | Sathyamoorthy R.,PG and Research | Saravanakumar R.,PG and Research | Velumani S.,CINVESTAV
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2010

III-VI compound semiconductors receive great attention due to its applications in memory devices, switching devices, gas sensors, hybrid solar cells, etc. InTe thin films were prepared by sequential thermal evaporation of In and Te at Ar atmosphere. X-ray diffraction pattern of the films shows that the films posses mixed phase of In2Te3 and In 2Te5. Grain size (D) and dislocation density were calculated by using Scherer's formula. Surface morphology of the film is analyzed by SEM and the surface is found to be agglomeration of well defined grains. EDS analysis reveals that elemental composition is in right stoichiometry. The value of capacitance and tan δ was recorded with respect to different frequencies and at different temperatures. It is observed that the capacitance decreases with increase in frequency at all temperatures. The observed nature of the capacitance is due to the inability of the dipoles to orient in a rapidly varying electric field. The pronounced increase in capacitance toward the low frequency region may be attributed to the blocking of charge carriers at the electrodes which leads to space charge layer resulting in the increase of capacitance. The mechanism responsible for AC conduction is found to be electronic hopping. TCC and TCP values were calculated and the results are discussed. © 2010 Elsevier B.V. All rights reserved.

Bharthasarathi T.,PG and Research | Murugakoothan P.,PG and Research
Optik | Year: 2014

A novel method has been found to enhance the metastable zone width of solutions in their supersaturated region in order to grow large size crystals at a faster rate under stabilized conditions. In which, the incorporation of a small quantity of ethylinediamine tetra acetic acid (EDTA) and hydrogen peroxide (H2O2) a well-known chelating agents, enhances Ostwold-Mier's metastable zone width significantly due to their chelating action. Also this incorporation reduces the secondary nucleation rate and enhances the growth rate of the crystal. Powder X-ray diffraction, Fourier transform infrared (FTIR), UV-visible-NIR studies for the grown crystal reveal that EDTA and H2O2 addition do not affect the crystalline quality. This concept has been realized with barium nitrate Ba(NO3)2, a potential SRS crystal. The complexation also promotes the growth rate leading to a rapid growth with high crystalline quality. © 2014 Elsevier GmbH. All rights reserved.

Angela D.V.R.,PG and Research | Sheshasaayee A.,PG and Research
ACM International Conference Proceeding Series | Year: 2015

Morphological learning through unsupervised means enables the automatic identification of affixes, morphological segmentation of words followed by the generation of paradigms incorporating the list of affixes with the combined list of stems for a particular language. For segmenting the words into stems and affixes various unsupervised approaches have been deployed. But for highly agglutinative languages like Tamil very less computational work has been done in this direction. This paper mainly portrays a morphology acquisition framework based on an unsupervised approach for the morphological segmentation of highly agglutinative Tamil language. © 2015 ACM.

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