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Parveen A.,Government First Grade College | Koppalkar A.R.,S S Margol College | Roy A.S.,Indian Institute of Science
IEEE Sensors Journal | Year: 2012

Polyaniline-CaTiO 3 nanocomposites with their various weight percentages were prepared by chemical oxidative in situ polymerization technique. The prepared composites were characterized by Fourier transform infrared spectroscopy, scanning electronic microscope, and X-ray diffraction. The temperature-dependent dc conductivity of polyaniline-CaTiO 3 nanocomposite was studied within the range of 40-200°C and found that 50 wt% shows high conductivity compared to other composites. Humidity sensor properties of polyaniline-CaTiO 3 nanocomposite show better sensing properties and exhibit good linearity in sensing response curve, which discuss the implications of distortions and nonstoichiometry on their physical properties. Among all composites, 50 wt% of polyaniline-CaTiO 3 nanocomposites show high sensitivity up to ∼90% and their response-recovery times are 500 and 453 s, respectively. © 2001-2012 IEEE. Source


Parveen A.,Gulbarga University | Roy A.S.,Government First Grade College
Advanced Materials Letters | Year: 2013

Polyaniline/TiO2 nanocomposites have been prepared by sol-gel technique using citric acid and saturated solution of a-dextrose as a surfactant in presence of hydroxyl group at an anomeric position in sugar chain. The FTIR spectrum indicates the benzenoid, quinoid and MO peaks confirm the formation of PANI/TiO2 nanocomposites. The XRD studies show the monoclinic structure and the TEM study of nano TiO2 reveals that the average particles size is 9 ±2 nm whereas the composite size is 13 ± 2 nm and further it is observed that the TiO2 nanoparticles are intercalated to form a core shell of PANI. The formation of core shell is significant up to 30wt% observed from the SEM. The TGA-DSC curves show the thermal stability of polyaniline and its nanocomposites at 660 °C of temperature. © 2013 VBRI press. Source


Rajendra D.,University | Roy A.S.,Gulbarga University | Parveen A.,Government First Grade College
Composites Part B: Engineering | Year: 2013

Polyethylene oxide-NaClO3 composite have been prepared by solution casting technique with different weight percentages as a polymer electrolyte for battery application. The prepared composites were characterized by various tools like XRD, FTIR and SEM. The X-ray diffraction analysis shows the complexation of polymer with salt and existence of both crystalline and amorphous phases. From FTIR spectra confirms the formation of PEO-NaClO 3 composites. SEM images shows the grains are highly agglomerated and its average size increases with increase in salt ratio. Frequency dependence of dielectric property and ac electrical conductivity of polymer electrolytes were studied within the frequency range of 50 Hz to 5 MHz using complex impedance analysis technique. Ionic conductivity follows Arrhenius type behavior as a function of temperature. The fabricated cell of 25 wt.% of PEO-NaClO3 composites generated high current of 1.79 A. © 2013 Elsevier Ltd. All rights reserved. Source


Roy A.S.,Indian Institute of Science | Gupta S.,Indian Institute of Science | Sindhu S.,Indian Institute of Science | Parveen A.,Government First Grade College | Ramamurthy P.C.,Indian Institute of Science
Composites Part B: Engineering | Year: 2013

In this study, the dielectric properties of PVA/ZnO nanocomposites films were evaluated. The composites were prepared by a solution casting technique. The dispersion and functionalization of the ZnO nanoparticles in the composite films were characterized by spectroscopic technique. The surface morphology of the PVA/ZnO nanocomposites films were elucidated using AFM. The charge transport properties were evaluated based on the dielectric and impedance spectroscopy techniques. Low ZnO loading composite shows low dielectric value at higher frequency and behaves as a lossless material. The complex impedance spectra suggest the change in conductivity, due to the change in bulk resistance of the materials and less relaxation time. Thus, all PVA/ZnO nanocomposites behave as lossless materials above 106 Hz indicating the composites are useful in microwave application. © 2012 Elsevier Ltd. All rights reserved. Source


Harinarayana N.S.,University of Mysore | Raju N.V.,Government First Grade College
Electronic Library | Year: 2010

Purpose - The purpose of this paper is to explore recent trends in the application of Web 2.0 and Library 2.0 features as exemplified through university library web sites around the world. Design/methodology/approach - The top 100 universities from the ranked list of 200 provided on the Times Higher Education web site were considered for collection of data and from this list a selection was made of 57 of these universities. This selection was based on whether the site was in English and whether it had at least one Web 2.0 feature. For each of these universities their web sites were visited and data on their Web 2.0 features (such as Blogs, RSS, Instant Messaging, Wikis and the like) were collected and analyzed. Findings - Results reveal that 37 university libraries use RSS feeds for dissemination of library news, events and announcements and 15 university libraries provide blog space for users. Whereas wiki is the least applied Web 2.0 technology, with only one university using it, Instant Messaging is another most widely applied feature with 37 libraries already providing reference service through it. Podcast (used in three libraries) and Vidcast (used in six libraries) are yet to become popular facilities to be offered in university library web sites. Research limitations/implications - The study is based on the university ranking for 2007, as the World Top 200 Universities 2008 was not published until October 2008 when this article was being finalized. However, this does not affect the outcome of the Web 2.0 features being utilized by the universities. Originality/value - Most of the earlier studies on the subject deal with Web 2.0 tools and how they could be used in the library context. The present paper, however, provides concrete evidence of the application of Web 2.0 in university libraries. As such it should prove of interest to all types of libraries, even though its context is university libraries. © Emerald Group Publishing Limited 0264-0473. Source

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