Faculty Publications
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Item LiClO4-doped plasticized chitosan and poly(ethylene glycol) blend as biodegradable polymer electrolyte for supercapacitors(Institute for Ionics, 2013) Sudhakar, Y.N.; Muthu, M.; Bhat, D.K.Biodegradable polymer electrolyte comprising the blend of chitosan (CS) and poly(ethylene glycol) (PEG) plasticized with ethylene carbonate and propylene carbonate, as host polymer, and lithium perchlorate (LiClO4), as a dopant, was prepared by solution casting technique. The ionic conductivity has been calculated using the bulk impedance obtained through impedance spectroscopy. The variation of conductivity and dielectric properties has been investigated as a function of polymer blend ratio, plasticizer content and LiClO4 concentration at temperature range of 298-343 K. The DSC thermograms show two broad peaks for CS/PEG blend and increased with increase in the LiClO4 content. The maximum conductivity has been found to be 1. 1 × 10-4 S cm-1 at room temperature for 70:30 (CS/PEG) concentration. The electric modulus of the electrolyte film exhibits a long tail feature indicative of good capacitance. The activation energy of all samples was calculated using the Arrhenius plot, and it has been found to be 0. 12 to 0. 38 eV. A carbon-carbon supercapacitor has been fabricated using this electrolyte, and its electrochemical characteristics and performance have been studied. The supercapacitor showed a fairly good specific capacitance of 47 F g-1. © 2012 Springer-Verlag.Item A direct approach towards synthesis of copper nanofluid by one step solution phase method(Elsevier B.V., 2024) Kumar, S.P.; Shenoy, U.S.; Bhat, D.K.We adopted a simple one step approach to synthesize copper nanofluids by reduction of copper sulphate with fructose. The solution phase synthetic technique led to the formation of copper particles whose size was restricted to the nanodimensions by use of sodium lauryl sulphate. We studied the effect of various parameters on the formation and dispersion of the copper nanoparticles in the base fluid containing a 1:1 mixture of water and ethylene glycol. The resulting Newtonian nanofluid was found to be highly stable with increased thermal conductivity. Thus, the applied technique is found to be simple, economic, and extendable to other class of materials to obtain stable dispersions of nanofluids for heat transfer applications. © 2024 Elsevier B.V.Item Design, synthesis, and characterization of stable copper nanofluid with enhanced thermal conductivity(Elsevier Ltd, 2024) Bhat, D.K.; Kumar, S.P.; Shenoy, U.S.Nanofluids, which are liquids that contain small particles with dimensions in the nanometer range, have gained significant attention in recent years due to their enhanced thermal properties in various applications such as thermal management and energy conversion. This article aims to provide insights into the design and optimization of copper nanofluid synthesis and it investigates the thermal and rheological properties at varying concentrations of nanoparticles and temperature. The method involves simultaneous use of fructose as reducing agent and polyvinyl pyrrolidone as stabilizing agent to enable synthesis of copper nanofluid from copper sulphate. The resulting Newtonian nanofluid had a stability of 3 months with enhanced thermal conductivity of up to ∼500 % compared to 1:1 mixture of water and ethylene glycol which served as the base fluid. The approach is suitable for producing large volume of nanofluid using cost effective materials. © 2024 Elsevier Ltd