Faculty Publications
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Item Studies on corrosion of Mg-Al-Zn alloy in 30% aqueous ethylene glycol(Trans Tech Publications Ltd ttp@transtec.ch, 2015) Medhashree, H.; Nityananda Shetty, A.The Mg-Al-Zn alloy is used in the coolant systems of automobile engines. Corrosion of Mg-Al-Zn engine components by coolants, which consist of 30% aqueous ethylene glycol as a coolant composition, is an important issue in automobile industries. With this preview, in the present study it is intended to study the effect of environmental contaminant sulphate ions on the corrosion behavior of Mg-Al-Zn alloy in 30% (v/v) aqueous ethylene glycol solution. Electrochemical investigations were carried out by potentiodynamic polarization and electrochemical impedance spectroscopy techniques. Scanning electron microscopy (SEM) and energy dispersion X-ray analysis (EDX) were used to study the surface morphology and composition of the alloy. Activation parameters for the corrosion process were calculated by conducting the corrosion studies at different temperatures. It was observed that corrosion rate of the alloy in 30% (v/v) aqueous ethylene glycol increases with the increase in the concentration of sulphate ions and also with the increase in temperature. © (2015) Trans Tech Publications, Switzerland.Item Synthesis and characterization of reduced- graphene oxide/ nickel oxide/ polyaniline ternary nanocomposites for supercapacitors.(Elsevier Ltd, 2018) Viswanathan, V.; Nityananda Shetty, A.Reduced graphene oxide, polyaniline and nickel oxide ternary nanocomposites were synthesized in series by changing the weight ratio of polyaniline adopting in-situ single step chemical method. Their structural characterization was carried out, employing, powder-XRD, IR spectroscopy, and scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX) techniques. Thus synthesized composites were tested for their electrode property by cyclic voltammetry (CV), galvanostatic charge discharge and electrochemical impedance spectroscopy (EIS) with two electrode system using 6 M KOH as electrolyte at different weight ratio of polyaniline. Of all composites synthesized the one with polyaniline weight of 100 mg rendered the maximum capacitance of about 153.37 F g-1 with corresponding energy and power densities of 13.63 W h kg-1 and 392.54 W Kg-1,respectively. It exhibited 100% retention of its initial capacitance up to 10000 charge - discharge cycles. The obtained performance is superior to the binary combination of constituent materials, namely, reduced graphene oxide, polyaniline and nickel oxide. © 2018 Elsevier Ltd.Item Electrochemical comparison of nickel and nickel hydroxide nanoparticles composited with reduced graphene oxide and polyaniline for their supercapacitor application(American Institute of Physics Inc. subs@aip.org, 2018) Viswanathan, A.; Nityananda Shetty, A.The reduced graphene oxide/polyaniline/Ni(OH)2 (GP-Ni(OH)2) and reduced graphene oxide/polyaniline/Ni (GP-Ni) nanocomposites were synthesized by facile in situ single step chemical method. The constituents were confirmed by powder-XRD, and the electrochemical characterizations were carried out using cyclic voltammetry(CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS). The electrochemical contribution of Ni(OH)2 and Ni to their supercapacitance along with reduced graphene oxide and polyaniline was compared. The GP-Ni nanocomposite exhibited a specific capacitance of 266.66 F g-1, energy density of 53.33 W h kg-1 and power density of 1385 W kg-1 at a current density of 0.25 A g-1 and the results were enhanced to 21% and more promising than that of nanocomposite GP-Ni(OH)2. © 2018 Author(s).Item Amelioration of supercapacitance of mixed metal oxide dispersed reduced graphene oxide and polyaniline nanocomposites using Ch3SO3H as supporting electrolyte in H2SO4(Elsevier Ltd, 2019) Viswanathan, A.; Nityananda Shetty, A.Reduced graphene oxide/polyaniline/ Cu2O-SnO2 (5:2) nanocomposite was synthesised by facile in-situ one step chemical method. Its composition and structural morphology were characterized using powder-XRD, energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). The capacitive performances were evaluated using cyclic voltammetry (CV), galvanostatic charge – discharge(GCD), and electrochemical impedance spectroscopy (EIS) with 0.4 M H2SO4 and a mixture of 0.4 M H2SO4 and 0.4 M CH3SO3H (1:1) as electrolytes. The amelioration of electrochemical parameters was observed in the mixture of electrolytes. The specific capacitance of 230.41 F g–1, energy density of 46.08 W h kg–1, and power density of 1530.39 W kg–1 were obtained. The enhancement of the electrochemical properties was found to be about 20 % with the mixture of 0.4 M H2SO4 and 0.4 M CH3SO3H (1:1) over bare 0.4 M H2SO4. © 2019 Elsevier Ltd. All rights reserved.Item Corrosion inhibition of aluminum type 6061 Al-15 vol. pct. SiC(p) composite in 0.5-M sodium hydroxide solution by 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol(Emerald Group Publishing Ltd. Howard House Wagon Lane, Bingley BD16 1WA, 2014) Reena Kumari, P.D.; Nayak, J.; Nityananda Shetty, A.Purpose: The purpose of this paper is to report the studies on the corrosion inhibition property of 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol (APTT) for the corrosion of 6061 Al-15 vol. pct. SiC(p) composite. Design/methodology/approach: The corrosion behavior of 6061 Al-15 vol. pct. SiC(p) composite was studied at different temperatures in 0.5-M sodium hydroxide (NaOH) solution in the presence of APTT by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopic techniques. The effect of inhibitor concentration and temperature on the inhibitor effect of APTT was studied. The surface morphology of the metal surface was investigated by scanning electron microscopy. The activation parameters for the corrosion of the composite and base alloy, as well as the thermodynamic parameters for the adsorption of APTT on the composite and alloy surfaces, were calculated. Findings: The inhibition efficiency of APTT increases with the increase in the concentration of the inhibitor and decreases with the increase in temperature. The adsorption of APTT on the composite was found to be through physisorption, obeying Langmuir's adsorption isotherm. APTT acts as a mixed inhibitor with predominant cathodic action on the composite. Practical implications: APTT can be used as an inhibitor for the corrosion of 6061 Al-15 vol. pct. SiC(p) composite in the NaOH medium. Originality/value: This paper provides information regarding the corrosion inhibition property of APTT on 6061 Al-15 vol. pct. SiC(p) composite. An attempt was made to explain the mechanism of the inhibition action by APTT. © Emerald Group Publishing Limited.Item Investigation of influence of medium ph and sulfate ion concentrations on corrosion behavior of magnesium alloy ZE41(Allerton Press Inc., 2014) Dinodi, N.; Nityananda Shetty, A.Magnesium alloys have emerged as potential structural materials with all capabilities to even replace close contenders; aluminium alloys in weight-critical applications. High susceptibility to corrosion being the only limitation, corrosion of magnesium alloys continues to gather much attention among the material scientists worldwide. ZE41 is one such alloy of magnesium which is increasingly gaining importance as automobile and aerospace material. In the present study the influence of the medium pH and sulfate ion concentrations on the corrosion behavior of magnesium alloy ZE41 has been investigated using electrochemical techniques like the Tafel extrapolation and electrochemical impedance spectroscopy (EIS). The tests have been carried out in a range of conditions, with gradually varying pH and sulfate ion concentration. The morphology and composition of the corroded alloy surface have been determined by the scanning electron microscopy (SEM) and energy dispersion X-ray (EDX) analysis, respectively. The recorded results reflect a trend of a higher corrosion rate associated with a higher sulfate concentration at each pH and with a lower pH at each sulfate concentration. © 2014 Allerton Press, Inc.Item Alkyl carboxylates as efficient and green inhibitors of magnesium alloy ze41 corrosion in aqueous salt solution(Elsevier Ltd, 2014) Dinodi, N.; Nityananda Shetty, A.Long chain alkyl carboxylates like stearate, palmitate and myristate were investigated for their efficiency in inhibiting the corrosion of magnesium alloy ZE41 in an aqueous salt medium containing 0.2M Na2SO4 and 0.1M NaCl. The techniques like potentiodynamic polarization and EIS, along with SEM and EDX analyses were employed. The inhibition was proposed to be the result of adsorption of alkyl carboxylates, which was found to obey the Langmuir adsorption isotherm. The inhibition was assumed to be the outcome of the formation of a compact modified surface film due to the precipitation of adsorbed alkyl carboxylates of magnesium. © 2014 Elsevier Ltd.Item Simple glucose reduction route for one-step synthesis of copper nanofluids(Springer Nature, 2014) Shenoy, S.U.; Nityananda Shetty, A.One-step method has been employed in the synthesis of copper nanofluids. Copper nitrate is reduced by glucose in the presence of sodium lauryl sulfate. The synthesized particles are characterized by X-ray diffraction technique for the phase structure; electron diffraction X-ray analysis for chemical composition; transmission electron microscopy and field emission scanning electron microscopy for the morphology; Fourier-transform infrared spectroscopy and ultraviolet–visible spectroscopy for the analysis of ingredients of the solution. Thermal conductivity, sedimentation and rheological measurements have also been carried out. It is found that the reaction parameters have considerable effect on the size of the particle formed and rate of the reaction. The techniques confirm that the synthesized particles are copper. The reported method showed promising increase in the thermal conductivity of the base fluid and is found to be reliable, simple and cost-effective method for preparing heat transfer fluids with higher stability. © 2012, The Author(s).Item Synthesis, structural characterization, and biological application of p-[N,N-bis(2-chloroethyl) aminobenzaldehyde thiosemicarbazone and its nickel (II) complex(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2015) Sankaraperumal, A.; Nityananda Shetty, A.; Karthikeyan, J.New complex of Ni(II) with p-[N,N-bis(2-chloroethyl)]aminobenzaldehyde thiosemicarbazone (CEABTSC) have been synthesized and characterized by elemental analysis, IR, electronic, and 1H NMR spectroscopy. The crystal structure of the free ligand has been determined by single-crystal X-ray diffraction technique. The compound crystallizes in the Triclinic crystal system with space group P-1, Z = 2, Calculated density = 1.392 mg/m3, V = 761.64(18) A3 with unit cell parameters a = 8.2847(11) Å, ? = 99.074°, b = 8.7432(12) Å, ? = 94.035(7)°, c = 11.2423(15) Å, ? = 107.337(6)°; final R1 and wR2 are 0.0796 and 0.3021, respectively. The crystal structure reveals that the compound exists in the thione form and C12 and C11 are at E configuration to each other with respect to N2-N3 bond. The packing of the molecules in the crystal lattice is stabilized by intramolecular N(3)-H(3).S(1) and N(4)-H(4D).S(1) hydrogen bonds resulting in the formation of edge fused R22(8) ring motif. In the complex, thiosemicarbazone ligand is coordinated to nickel through (1:2 complex) SNNS mode. The complex has been tested for their antibacterial activity against various pathogenic bacteria. © 2015 Copyright © Taylor & Francis Group, LLC.Item Fabrication of hair and copper fiber reinforced polymethyl methacrylate (pmma) composites and evaluation of their mechanical properties, thermal conductivity and color stability for dental applications(Society for Biomaterials and Artificial Organs - India sharmacp@sbaoi.org, 2016) Jayaprakash, K.; Nandish, B.T.; Rijesh, M.; Nayak, J.; Bhat, S.M.; Shetty, K.H.K.; Nityananda Shetty, A.; Prabhu, S.The objective of the work was to fabricate and evaluate the impact strength, flexural strength, thermal conductivity and color stability of heat cure Polymethyl methacrylate denture base resin, reinforced with human hair fibers and copper fibers. Specimens were prepared by reinforcing human hair fibers of 2mm length and diameter in the range of 64 -78 ?m, in different quantities with respect to two different age groups and genders, to polymer-monomer mix before dough stage. Same procedure was followed to fabricate specimens with copper fibers (2mm length and 200 ?m diameter) too. The impact strength, transverse strength, thermal conductivity, and color stabilities were measured by using standard equipment's. Scanning electron microscope (SEM) was used to study the fractured surface of the fiber reinforced composites. The impact strength increased three times in hair reinforced and about twice in copper reinforced composites. The transverse strength was slightly decreased and the cause for it was investigated. Copper fiber reinforced composite significantly increased the thermal conduction. The human hair and copper reinforced Polymethyl methacrylate showed significant improvements in its mechanical properties and retained color stability similar to control specimens during storage in various beverages.