Faculty Publications
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Item Protein Recovery Using Biodegradable Polymer(wiley, 2022) Panchami, H.R.; Isloor, A.M.; A.F., A.F.; Susanti, R.Globally, with the consistent increment in population growth and urbanization, the demand for freshwater and food production is also increasing. Present conservation concerns about the limited availability of renewable resources and include disposal, recovery, and reuse for socioeconomic impact. The valuable resources include organic matter and essential nutrients, especially proteins, wasted in the wastewater stream. Developing efficient methodology using renewable and green technology is mandatory to recover valuable proteins and other nutrients with high production efficiency. In recent years, biodegradable polymers and the processes using biodegradable polymers are gaining wide attention from researchers. Such green processes/technologies are suitable for the recovery of proteins. Present short communication emphasizes the review of processes/technology using biodegradable polymer and the necessity for recovering or restoring valuable proteins from wastewater. © 2022 Scrivener Publishing LLC.Item Optical characterization of a new Donor-acceptor type conjugated polymer derived from 3,4-diphenylthiophene(2009) Manjunatha, M.G.; Vasudeva Adhikari, A.V.; Hegde, P.K.; Suchand Sandeep, C.S.; Philip, R.A new donor-acceptor type poly{2-(3,4-didecyloxythiophen-2-yl)-5-[3,4- diphenyl-5-(1,3,4-oxadiazol-2-yl)thiophen-2-yl]-1,3,4-oxadiazole} (P1) has been designed and synthesized starting from thiodiglycolic acid, 1,2-diphenylethane- 1,2-dione, and diethyl oxalate through multi-step reactions using precursor polyhydrazide route. The charge-transporting and linear optical property of the polymer has been investigated by cyclic voltammetric, UV-visible, and fluorescence emission spectroscopic studies. The UV-visible absorption spectrum of polymer in thin film form showed maxima at 420 nm. The polymer displayed bluish-green fluorescence both in solution and thin film form. The optical band gap is determined to be 2.27 eV. Third-order nonlinear optical property of the new polymer has been investigated at 532 nm using single beam Z-scan and degenerate four wave mixing (DFWM) techniques with nanosecond laser pulses. The absorptive nonlinearity observed for the polymer P1 is of optical limiting type, which arises due to an "effective" three-photon absorption (3PA) process. The third-order nonlinear optical susceptibility (?(3)) of the polymer is found to be 0.831 × 10-12 esu. Both linear and nonlinear optical studies revealed that the new polymer (P1) is a promising material for applications in photonic devices. © 2009 Springer Science+Business Media, LLC.Item LiClO4-doped plasticized chitosan as biodegradable polymer gel electrolyte for supercapacitors(2009) Muthu, M.S.; Bhat, D.K.Studies on redox supercapacitors using electronically conducting polymers are of great importance for hybrid power sources and pulse power applications. In this study, electrochemical properties of a chitosan-based biodegradable polymer gel electrolyte (PGE) and a p/p polypyrrole supercapacitor fabricated using this electrolyte have been investigated. The variation of conductivity and dielectric properties of the electrolyte film with temperature has also been measured. The PGE film chosen for the study exhibited a specific conductivity of 5.5 × 10-3 S cm~. The electric modulus of the electrolyte film exhibits a long tail feature indicative of good capacitance. The fabricated supercapacitor showed a fairly good specific capacitance of 120 F g-1 and a time constant of 1 s. © 2009 Wiley Periodicals, Inc.Item Nonlinear optical studies on new conjugated poly{2,2 l-(3,4- dialkoxythiophene-2,5-diyl) bis[5-(2-thienyl)-1,3,4-oxadiazole]}s(2010) Hegde, P.K.; Vasudeva Adhikari, A.V.; Manjunatha, M.G.; Suchand Sandeep, C.S.; Philip, R.Three new donor-acceptor type poly{2,2 1-(3,4-dialkoxythiophene- 2,5-diyl)bis[5-(2-thienyl)-1,3,4-oxadiazole]}s (P1, P2, and P3) were synthesized starting from thiodiglycolic acid and diethyl oxalate through multistep reactions. The polymerization was carried out using chemical polymerization technique. The optical and charge-transporting properties of the polymers were investigated by UV-visible, fluorescence emission spectroscopic and cyclic voltammetric studies. The polymers showed bluish-green fluorescence in solutions. The electrochemical band gaps were determined to be 2.03, 2.09, and 2.17 eV for P1, P2, and P3, respectively. The nonlinear optical properties of new polymers were investigated at 532 nm using single beam Z-scan and degenerate four-wave mixing (DFWM) techniques with nanosecond laser pulses. The polymers exhibited strong optical limiting behavior due to "effective" three-photon absorption. Values of the effective three-photon absorption (3PA) coefficients, thirdorder nonlinear susceptibilities (? (3)), and figures (F) of merit were calculated. © 2010 Wiley Periodicals, Inc.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 Tubular array, dielectric, conductivity and electrochemical properties of biodegradable gel polymer electrolyte(Elsevier Ltd, 2014) Sudhakar, Y.N.; Muthu, M.; Bhat, D.K.A supercapacitor based on a biodegradable gel polymer electrolyte (GPE) has been fabricated using guar gum (GG) as the polymer matrix, LiClO4 as the doping salt and glycerol as the plasticizer. The scanning electron microscopy (SEM) images of the gel polymer showed an unusual tubular array type surface morphology. FTIR, DSC and TGA results of the GPE indicated good interaction between the components used. Highest ionic conductivity and lowest activation energy values were 2.2 × 10-3 S cm-1 and 0.18 eV, respectively. Dielectric studies revealed ionic behavior and good capacitance with varying frequency of the GPE system. The fabricated supercapacitor showed a maximum specific capacitance value of 186 F g -1 using cyclic voltammetry. Variation of temperature from 273 K to 293 K did not significantly influence the capacitance values obtained from AC impedance studies. Galvanostatic charge-discharge study of supercapacitor indicated that the device has good stability, high energy density and power density. © 2013 Elsevier Ltd. All rights reserved.Item Effect of acid dopants in biodegradable gel polymer electrolyte and the performance in an electrochemical double layer capacitor(Institute of Physics Publishing custserv@iop.org, 2015) Sudhakar, Y.N.; Muthu, M.; Bhat, D.K.Proton-conducting biodegradable gellan gum gel polymer electrolytes (GPEs) have been prepared using three different dopants, namely ortho-phosphoric (o-H3PO4), sulfuric (H2SO4) and hydrochloric acids (HCl). The GPEs were cross-linked using borax. The polymeric gels were characterized by spectroscopic, thermal, ionic conductivities and dielectric measurements. Proton conductivity was in the range of 5.1 × 10-3 to 3.7 × 10-4 s cm-1 and activation energies were between 0.14 meV and 0.19 meV, at different temperatures. Among the doped acids, the H3PO4 doped GPE exhibited thermal stability at varying temperature. Electrochemical double layer capacitors (EDLCs) were fabricated using activated carbon as electrode material and GPEs. The EDLCs were tested using cyclic voltammetry, ac impedance spectroscopic and galvanostatic charge-discharge techniques. The maximum specific capacitance value was 146 F g-1 at a scan rate of 2 mV s-1. Quite stable values were obtained at a constant current density up to 1000 cycles. © 2015 The Royal Swedish Academy of Sciences.Item Preparation and characterization of phosphoric acid-doped hydroxyethyl cellulose electrolyte for use in supercapacitor(SpringerOpen, 2015) Sudhakar, Y.N.; Muthu, M.; Bhat, D.K.A new borax cross-linked biodegradable solid polymer electrolyte based on hydroxyethyl cellulose and phosphoric acid (H3PO4) was prepared. Characterizations of doped and undoped SPE were done using Fourier transform infrared spectroscopic and electrochemical studies. The ionic conductivity of the films increased with increase in acid concentration and the ionic conductivity obtained at 303 K was 4.1 × 10-3 S cm-1. Furthermore, effects of acid concentration on ionic conductivity and activation energy were discussed. Dielectric studies showed long tail-like feature indicating capacitive nature. A supercapacitor was fabricated and its electrochemical characteristics were studied. The supercapacitor showed a fairly good specific capacitance of 83 F g-1 at 2 mV s-1 and galvanostatic charge-discharge studies showed the mirror-like pattern with 98 % columbic efficiency. Cyclic stability was measured up to 2000 cycles. © 2015 The Author(s).Item Characterization of composites based on biodegradable poly(vinyl alcohol) and nanostructured fly ash with an emphasis on polymer-filler interaction(SAGE Publications Ltd info@sagepub.co.uk, 2016) Patil, A.G.; SelvaKumar, M.; Anandhan, S.A thermal power station fly ash (FA) was mechanochemically activated by high-energy ball milling that yielded nanostructured FA. This nanostructured FA was incorporated into biodegradable poly(vinyl alcohol) (PVA) matrix by solution mixing and ultrasonication. Transmission electron micrographs revealed that the smooth spherical particles of FA were changed into irregular and rough ones; in addition, the particle size of FA was reduced to a few hundred nanometers, and its specific surface area value increased after the high-energy milling process. All these factors, in turn, led to a thermodynamically favorable interaction between the mechanochemically activated FA and PVA as evidenced by Fourier transform infrared spectroscopy. The incorporation of a very small amount of the nanostructured FA led to an increase in crystallinity of the polymer matrix. The glass transition temperature of the PVA matrix increased by about 18°C when 5 wt% of the nanostructured FA was used as the reinforcement. © The Author(s) 2014.Item Effect of exhaust gas recirculation on a CRDI engine fueled with waste plastic oil blend(Elsevier Ltd, 2018) Ayodhya, A.S.; Lamani, V.T.; Bedar, P.; Kumar, G.N.The inevitable rise in the usage of plastic poses a serious threat to the environment owing to their non-biodegradable nature. The lack of proper infrastructure for treating and recycling plastic wastes give rise to the disposal problem. However, the oil synthesized from these waste plastics can be used as an alternative fuel for C.I engines which not only helps to tackle the disposal problem but also aids in recovering precious energy from these wastes. This experimental investigation aims to study the effects of plastic-diesel blend(P30) fuel on the performance, emission and combustion characteristics of a twin cylinder CRDI engine operating at different EGR rates (0%, 10% and 20%). The experimental results showed a slight drop in the engine performance while operating with plastic blend, mainly overall due to its higher viscosity and lower heating value. The vast upsurge of NOX emissions with plastic blend was mitigated by the aid of EGR methodology. Marginal increase in the discharge of regulated emissions like HC, CO and soot were noticed for both plastic blend as well as EGR operations. The experiments were carried out for five different loading conditions varying from 0% to 80% in steps of 20% each and found out that waste plastic-diesel blend can be successfully used as an alternative fuel in diesel vehicles without any prior modifications in the engine. © 2018 Elsevier Ltd