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Andal V.,Center for Material Science
International Journal of ChemTech Research | Year: 2015

Nano-Fe2O3 was synthesized by precipitation method using starch as the precipitating agent. The characterization of the samples by XRD (X-ray diffraction) technique confirmed the formation of Fe2O3..Analysis by SEM (scanning electron microscope) was carried out to study the morphology and particle size. The SEM image shows that the particles are spherical in nature. The as prepared samples contained rhombohedral phase. MR fluid was prepared using Fe2O3 nano powder, silicone oil and grease. The aim of the work was to determine the viscosity of the MR fluid, under the influence of different values of electromagnetic field. To determine the viscosity and damping coefficient a modified experimental setup was fabricated. © 2015, Sphinx Knowledge House. All rights reserved.


Kalyva M.,Foundation for Research and Technology Hellas | Orava J.,University of Cambridge | Orava J.,Tohoku University | Siokou A.,Foundation for Research and Technology Hellas | And 5 more authors.
Advanced Functional Materials | Year: 2013

Structural transitions in materials are accompanied by appreciable and exploitable changes in physical-chemical properties. Whereas reversible optically-driven atomistic changes in crystal-to-amorphous transitions are generally known and exploited in applications, the nature of the corresponding polyamorphic transitions between two structurally distinct meta-stable amorphous phases is an unexplored theme. Direct experimental evidence is reported for the nature of the atomistic changes during fully reversible amorphous-to-amorphous switching between two individual states in the non-crystalline As 50Se50 films prepared by pulsed-laser deposition and consequent changes in optical properties. Combination of surface sensitive X-ray photoelectron spectroscopy and spectroscopic ellipsometry show that the near-bandgap energy illumination and annealing induce reversible switching in the material's structure by local bonding rearrangements. This is accompanied by switching in refractive index between two well-defined states. Exploiting the pluralism of distinct structural states in a disordered solid can provide new insights into the data storage in emerging optical memory and photonic applications. X-ray photoelectron spectroscopy and spectroscopic ellipsometry are combined to study reversible switching in the structure and optical properties of As50Se50 thin films prepared by pulsed-laser deposition. Switching is driven by near-bandgap light illumination and thermal annealing. The mechanism, namely, the amorphous-to-amorphous transition, is unique for pulsed-laser-deposited films. No such effect is observed for films of the same composition prepared by thermal evaporation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Jayanthi S.N.,Center for Material Science | Prabakaran A.R.,Pachaiyappas College | Subashini D.,Pachaiyappas College | Thamizharasan K.,Sir Theagaraya College
Materials Today: Proceedings | Year: 2015

L-histidinium perchlorate, a semi-organic crystal has been grown by slow evaporation solution growth technique at room temperature. The growth of L-histidinium perchlorate was confirmed by single crystal X-ray diffraction analyses. Results of indentation-induced hardness testing are presented. The Vicker's hardness of the material in the load range 10-100g was 29-59Kg/mm2. The values of elastic stiffness constant, fracture mechanics, brittleness index and yield strength have also been calculated. The dielectric measurements of the crystal in the frequency range 100Hz-1MHz were investigated. The activation energy of electrical processes was also calculated and reported. © 2015 Elsevier Ltd.


Kumar M.,Pondicherry University | Kumar M.,Center for Material Science | Subramania A.,Pondicherry University | Balakrishnan K.,Pondicherry University
Electrochimica Acta | Year: 2014

Co3O4 nanofibers are prepared by electrospinning technique and they are characterized by thermogravimetry analysis (TG), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) studies. BET analysis revealed that Co3O4 nanofibers have high specific surface area. Electrochemical properties of the electrospun Co3O4 nanofibers electrode performance are characterized by cyclic voltammetry (CV) and galvanostatic charge-discharge measurements in a 6 M KOH electrolyte using a three-electrode system. The electrospun Co3O4 nanofibers exhibit a specific capacitance of 407 F g-1 at a scan rate of 5 mVs-1. Futhermore, the Co3O4 nanofibers show an excellent cycle stability and better capacity rentation with 94% after 1000 continuous charge-discharge cycles at a constant current density of 1 Ag-1. Moreover, the enhanced supercapacitor performance is mainly due to its unique nanofibers structure provides larger reactive surface area capable of fast ion and electrone transfer. The results are compared with the existing reported systems in the literature. © 2014 Elsevier Ltd. All rights reserved.


Lakshmipathy R.,Center for Material Science | Sarada N.C.,Vellore Institute of Technology
Desalination and Water Treatment | Year: 2016

This study reports the feasibility of waste watermelon rind as adsorbent for the removal of methylene blue in batch and continuous column studies. Batch mode adsorption studies were performed by varying the batch parameters such as pH, contact time, adsorbent dose, initial dye concentration, and temperature. The equilibrium data were analyzed with Langmuir, Freundlich, and Temkin isotherm models and found to better with Langmuir and Temkin models. The kinetic data reveal that the present system follows pseudo-second-order kinetic model. Thermodynamic studies reveal that the present process is spontaneous and exothermic in nature. Fixed bed column studies were performed by varying the column parameters such as flow rate, bed height, and initial inlet concentration. The breakthrough curves obtained were analyzed with Adams–Bohart, Thomas, and Yoon–Nelson models. The results show that watermelon rind an agro waste can be successfully employed for the elimination of methylene blue from aqueous solution. © 2015 Balaban Desalination Publications. All rights reserved.


Venugopalarao G.,Vellore Institute of Technology | Lakshmipathy R.,Center for Material Science | Sarada N.C.,Vellore Institute of Technology
International Journal of Nanomedicine | Year: 2015

Background: The application of antibiotics has been limited due to weak biodistribution and pharmacokinetics. Encapsulation of these drugs in lipid vesicles might be a good solution for obtaining the required properties. Liposomes are one of the most suitable drug-delivery systems to deliver the drug to the target organ and minimize the distribution of the drug to non-target tissues. Objective: The study reported here aimed to develop cefditoren pivoxil liposomes by thin-film hydration, characterize them in terms of physical interactions, and undertake in vitro and in vivo release studies. Methodology: The pre-formulation studies were carried out using Fourier-transform infrared spectroscopy and differential scanning calorimetry. Cefditoren pivoxil liposomal formulations were formulated by thin-film hydration using biomaterials ie, soya lecithin and cholesterol in different molar ratios. The best molar ratio was determined by in vitro studies such as entrapment efficacy, particle size distribution, and diffusion. Results: From the in vitro release studies, it was found that the formulation that contained soya lecithin and cholesterol in a 1.0:0.6 molar ratio gave good entrapment of 72.33% and drug release of 92.5% at 36 hours. Further, the formulation’s zeta potential and surface morphology were examined and stability and in vivo studies were undertaken evaluating the pharmacokinetic parameters, which showed promising results. Conclusion: Formulation CPL VI showed the maximum drug-loading capacity of 72.3% with good controlled release and acceptable stability when compared with the other formulations. In vivo studies in rabbits showed that the drug release from the liposomes was successfully retarded with good controlled release behavior which can be used to treat many bacterial infections with a minimal dose. © 2015 Venugopalarao et al.


Maheswari A.,Center for Material Science | Gopal A.,Center for Material Science
International Journal of ChemTech Research | Year: 2015

A comparative study of biodiesel production from waste cooking oil using green synthesized nano Fe2O3 and CuO impregnated nano Fe3O4 was carried out. Biodiesel is an alternative to fossil fuel which provides solution to many environmental problems. Nano Fe2O3 was green synthesized usingCalotropis gigantean milk as a reducing and gelling agent at 60oC.CuO impregnated Fe3O4 was synthesized using green synthesized Fe2O3 and Copper nitrate solution. The synthesized powders were characterized by powder XRD, FTIR and FESEM. The effects of reaction time (2 to 6 h),reaction temperature (60∘C), methanol/oil molar ratio (6 to 25), catalyst loading (3wt%), and reusability of catalyst (1 to 4 times) on the conversion to biodiesel were studied. © 2015, Sphinx Knowledge House. All rights reserved.


Lakshmipathy R.,Center for Material Science | Sarada N.C.,Vellore Institute of Technology
Desalination and Water Treatment | Year: 2015

Chemically protonated watermelon rind (PWR) was evaluated as a low-cost and efficient adsorbent for the removal of Pb2+ and Cu2+ ions from aqueous solution. Protonation of watermelon rind (WR) was carried out with 0.1 M HCl as protonating agent. The adsorption process was found to be spontaneous and exothermic in nature. Kinetic investigations suggest that the present system follows pseudo-second-order kinetic model and rate-limiting step is not chemical reaction. The maximum loading capacity of PWR was found to be 116.2 and 39.2 mg g−1 for Pb2+ and Cu2+ ions, respectively. FTIR and energy dispersive X-ray analyses supported the sorption of metal ions onto PWR. The results suggested that WR can be an effective adsorbent for the removal of heavy metal ions from aqueous solution. © 2015 Balaban Desalination Publications. All rights reserved.


Kannaiyan S.,Center for Material science | Andal V.,Center for Material science
International Journal of ChemTech Research | Year: 2015

Syntheses of materials with antibacterial property are immense field of research in material science. In this paper biologically active new fuchsin based Schiff base (condensation reaction of new fuchsin and salicylaldehyde) was functionalised on green synthesized Ag nanoparticle. The Schiff base stabilized Ag nanoparticle wascharacterized by XRD, FT-IR, SEM and UV-Vis spectroscopy techniques. XRD pattern shows the formation of nanosilver with face-centered cubic structure. The FT-IR spectrum confirms the formation and stabilization of Schiff base over the Ag nanoparticle. SEM analysis confirms that particles areelongated in shape. Antibacterial activities ofprepared compounds were studied on Gram positive (Bacillus cereus, Staphylococcus aureus)and Gram negative (Escherichia coli, Klebsiellapneumonia) bacteria.The results revealed that Schiff base capped Ag nanoparticle showed high biological activity than Schiff base. © 2015, Sphinx Knowledge House. All rights reserved.


Lakshmipathy R.,Center for Material Science | Sarada N.C.,Vellore Institute of Technology
Environmental Science: Water Research and Technology | Year: 2015

The present study reports the feasibility of removing Pb2+ ions from aqueous solution using watermelon rind (WR) as a low cost adsorbent. Fixed bed column studies were employed to study the removal efficiency of Pb2+ ions by varying the column parameters such as flow rate, bed height and initial metal ion concentration. The results showed that breakthrough and exhaustion time increases with a decrease in flow rate, inlet concentration, and an increasing bed height. The breakthrough curves obtained were analyzed with Adams-Bohart, Thomas and Yoon-Nelson models. On comparison of the R2 values, both the Thomas and Yoon-Nelson models were found to have a better fit than the Adams-Bohart model and these two models can be used to predict the adsorption of Pb2+ ions in a fixed bed column. Desorption of Pb2+ ions on WR was repeated for three cycles in 0.1 M HCl solution. The loading capacity of WR was compared with other adsorbents and was found to be high. These results show that watermelon rind, a non-hazardous agro waste, can be successfully employed for the elimination of Pb2+ ions from aqueous solution. © 2015 The Royal Society of Chemistry.

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