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G. Rajesh Kannan,P. Sathiya,T. Deepan Bharathi Kannan,M. Bhuvanesh Kumar 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.9
In this work, the technique of spin arc welding has been used to weld HSLA steel of grade 15CDV6. Experiments wereperformed according to the L9 Taguchi matrix using current, travel speed, wire feed rate, and spin rotation speed as inputparameters. The quality of the weld was analysed by measuring the bead geometry and microhardness. The Whale OptimizationAlgorithm (WOA) was used to identify the optimized welding parameters. The optimised parameters were identifiedthrough WOA as follows: current 230 A, voltage 24 V, travel speed 720 mm/min, and spin rotation speed 1500 rpm. Thepost-weld heat treatment (PWHT) was performed on the optimised welded sample to enhance the weld properties. Themicrohardness was increased by 79% after PWHT. Ferrite content was found to have reduced after welding and PWHT thegrain size and structure of the BM, HAZ, and WM were analysed by EBSD technique. The decrease in ferrite content hada significant effect on the microhardness. The Energy Dispersive Spectroscopy results showed the presence of Vanadiumcarbide (VC) precipitates which helped in increasing the microhardness.
Kannan Pugazhendhi,Raghunathan Malathi,Mohan Thangarajeswari,Palanivelu Shanthi,Periandavan Kalaiselvi 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.3
BACKGROUND: Endogenous pancreatic b-cell regeneration is a promising therapeutic approach for enhancing b-cell function and neogenesis in diabetes. Various findings have reported that regeneration might occur via stimulating b-cell proliferation, neogenesis, or conversion from other pancreatic cells to b-like cells. Although the current scenario illustrates numerous therapeutic strategies and approaches that concern endogenous b-cell regeneration, all of them have not been successful to a greater extent because of cost effectiveness, availability of suitable donors and rejection in case of transplantation, or lack of scientific evidence for many phytochemicals derived from plants that have been employed in traditional medicine. Therefore, the present study aims to investigate the effect of gymnemic acid (GA) on b-cell regeneration in streptozotocin-induced type 1 diabetic rats and high glucose exposed RIN5-F cells. METHODS: The study involves histopathological and immunohistochemical analysis to examine the islet’s architecture. Quantitative polymerase chain reaction (qPCR) and/or immunoblot were employed to quantify the b-cell regeneration markers and cell cycle proliferative markers. RESULTS: The immunoexpression of E-cadherin, b-catenin, and phosphoinositide 3-kinases/protein kinase B were significantly increased in GA-treated diabetic rats. On the other hand, treatment with GA upregulated the pancreatic regenerative transcription factor viz. pancreatic duodenal homeobox 1, Neurogenin 3, MafA, NeuroD1, and b-cells proliferative markers such as CDK4, and Cyclin D1, with a simultaneous downregulation of the forkhead box O, glycogen synthase kinase-3, and p21cip1 in diabetic treated rats. Adding to this, we noticed increased nuclear localization of Pdx1 in GA treated high glucose exposed RIN5-F cells. CONCLUSION: Our results suggested that GA acts as a potential therapeutic candidate for endogenous b-cell regeneration in treating type 1 diabetes.
Controlled synthesis of highly spherical nano-PbO2 particles and their characterization
Kannan, K.,Muthuraman, G.,Moon, Il Shik Elsevier 2014 Materials letters Vol.123 No.-
This letter describes the chemical synthesis of highly mono-dispersed spherical nano-PbO2. In the first step, sodium borohydride in the presence of TritonX-100 was used to reduce Pb(NO3)(2) to highly spherical nano-Pb, and the second NaOCI was used to oxidize nano-Pb to nano-PbO2 (both reactions were performed at room temperature). TEM, SEM, XRD, and XPS surface analyses showed that the prepared Pb and PbO2 particles were spherical, 95% were mono-dispersed and of the size of 30 nm. In addition, electrochemical active surface area studies confirmed the nano-particulate nature of the prepared PbO2 particles. The developed procedure is straightforward, rapid, performed at room temperature, and scalable to the industrial level. (C) 2014 Elsevier B.V. All rights reserved.
Effect of Bi-acids in the electrochemical synthesis of PbO2 electrode and its characterisations
( Kannan Karunakaran ),( G. Muthuraman ),문일식 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1
PbO<sub>2</sub> is a semiconductor but behave like a metal due to the property of non stoichiometric ratio of Pb and oxygen in the PbO<sub>2</sub> composition. Thus, it is still used as anodic material in real application such as Ozone production, and degradation of organic pollutants. Effective coating of PbO<sub>2</sub> is a toughest issue in HNO<sub>3</sub> medium due to evolution of NO<sub>2</sub> and NO<sub>X</sub> gases during electrolysis. Therefore, addition of supporting electrolyte might minimize such problems and enhance the PbO<sub>2</sub> coating. Here, we have demonstrated some inorganic acids as a supporting electrolyte in HNO<sub>3</sub> bath with different current densities. The effective deposition of PbO<sub>2</sub> was observed in different acids combination rather than single electrolyte. The material was Characterized by the XRD, SEM and Cyclic voltammetry techniques.
High speed switching in quantum Dot/Ti-TiOx nonvolatile memory device
Kannan, V.,Kim, H. S.,Park, H. C. Springer Science + Business Media 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.2
<P>We report a Ti-TiOx/CdSe-ZnS core-shell quantum dot based bipolar nonvolatile resistive memory device. The device exhibits an ON/OFF ratio of 100 and is reproducible. The memory device showed good retention characteristics under stress and excellent stability even after 100,000 cycles of switching operation. The switching speed measured was around 15 ns. The devices are solution processed at room temperature in ambient atmosphere. The operating mechanism is discussed based on charge trapping in quantum dots resulting in the Coulomb blockade effect with a ZnS shell layer and metal-oxide layer acting as the barrier to confine the trapped charges. The proposed mechanism is validated by a three terminal device designed exclusively for this purpose.</P>
Kannan, R.,Kim, A.R.,Kim, J.S.,Yoo, D.J. Pergamon Press ; Elsevier Science Ltd 2016 International journal of hydrogen energy Vol.41 No.40
<P>Nanoarchitectured carbon-palladium quantum dot (C-Pd)-supported manganese-titanium oxide/3D graphene (MTOx-3DG) catalyst is developed using a two-step process, for ethylene glycol fuel cells and oxygen evolution reactions. About 10 nm-sized carbon shell and a 5 nm-sized Pd catalyst over an MTOx-3DG support is established by the facile green chemical approach. The C-Pd-MTOx-3DG nanoarchitectured catalyst possesses excellent electrocatalytic activity with the peak current density of 23.8 mA/cm(2) for ethylene glycol electrooxidation. In addition, MTOx-3DG support material helps to remove the poisonous intermediates formed during the ethylene glycol electrooxidation. We addressed this point by suitable method in which about 80% of the poisonous compounds are removed, with the help of a supporting material at higher forward potential regions. In addition to that the formation of Pd adatoms and synergism of mixed metal atoms helped to effectively oxidize the fuel. The physical and chemical analyses show that the prepared C-Pd-MTOx-3DG electrocatalyst is nanostructured, with excellent catalytic activity, better intermediate tolerance, and sound long-term stability of the catalyst, attributed to the uniform dispersion of the Pd QDs and excellent interaction between the noble metal catalyst and the support. The present study sketches a simple and novel electrocatalyst for direct ethylene glycol fuel cells. (C) 2016 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.</P>
Kannan Karunakaran,Muthuraman Govindan,문일식 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.42 No.-
A combination of potential widening and electrocatalyst bimetallic oxide CoOx/PbO2 was chemicallysynthesized at room temperature for the first time. Nano-metals of Pb and Co were synthesized by usingNaBH4 in presence of surfactant solution, then the respective metal oxides made by addition of NaOCl. Analyses results obtained by XRD, SEM, TEM, XPS, UV-Visible, and FTIR indicated the resulting productswere PbO2 and CoOx. The mixed CoOx/PbO2 oxide prepared in this manner demonstrated a crystallinemorphology. CoOx/PbO2 mixed oxides with different Co to Pb ratios were investigated to understandwhether the prepared CoOx/PbO2 oxides are in guest/host stack arrangement. XRD, XPS, and TEManalyses of at a Pb to Co ratio of 1:1 ratio revealed the formation of bimetallic oxides of CoOx/PbO2 androd like morphology of pure CoOx turned to spherical like morphology with PbO2 demonstrated CoOx asguest of PbO2. For CoOx/PbO2 produced at higher Co to Pb ratios CoOx dominated the surface, meaningPbO2 was a guest of CoOx. The described optimized method provides a straightforward, convenient wayof synthesizing nano-mixed metal oxides at low temperature.
Kannan, Ramanujam,Kim, Ae Rhan,Nahm, Kee Suk,Yoo, Dong Jin American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.3
<P>The development of a facile, instep, and eco-friendly synthesis method of mono-dispersed low quantity palladium nanoparticle/carbon@functionllized carbon nanotube composite (Pd@C-f-CNT) electrocatalytic material was developed for use in the electrooxidation of xylitol. The prepared nanocatalyst was analyzed by powder X-ray diffraction analysis, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning and transmission electron microscopy. The electrocatalytic studies were performed using voltammetric methods. Formation of Pd NPs was observed within 2 min. The microscopic analysis showed 5- to 10-nm-sized Pd NPs that uniformly covered the CNT. The instep-formed carbon helped to improve the electrocatalytic activity of the catalyst. Our proposed method provides new insight for the development of highly efficient metal NPs/CNT nanocatalyst for direct alcohol fuel cell applications.</P>
( Kannan Karunakaran ),( Subramanian Balaji ),김정훈,이보열,문일식 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
Zeolites are complex alumino silicate molecules with specific porosity and pore size distribution. These unique properties make them to be used as molecular sieves in many industrial applications particularly in petrochemical industries. When precursor molecules for the synthesis of zeolites are coated over alumina tubes and subjected to controlled thermal heating, zeolites are formed by in situ growth over the alumina tubes. These tubular materials with coated zeolite materials act as tubular membranes and finds use in electrochemical tubular reactors as the separator. In the present investigation we have employed zeolite coated ceramic membranes for the metal ion oxidation in sulfuric acid medium. Here, we present the results on Cobalt(II) oxidation in sulfuric acid medium carried out under the various process parameters such ascurrent density of the electrodes, metal ion concentration and concentration of the acid electrolyte.