Expeditious and eco-friendly fabrication of highly uniform microflower superstructures and their applications in highly durable methanol oxidation and high-performance supercapacitors

Radhakrishnan, S.,Kim, H. Y.,Kim, B. S. Royal Society of Chemistry 2016 Journal of Materials Chemistry A Vol.4 No.31

<P>It is important to exploit copper sulfide products with desired structures as well as their potential applications due to their simple synthesis, low-cost and low toxicity. In this work, a novel 3D copper sulfide (CuS) microflower (MF) superstructure was fabricated on a large scale through a facile, environment-friendly and inexpensive synthesis method. The as-prepared CuS superstructures with a diameter of about 4.0 +/- 0.5 gm are assembled from large amounts of interleaving nanosheets, which have a uniform thickness of about 15 +/- 3 nm. The effect of reaction time, temperature, solvents and different copper and sulfur sources on the formation of the 3D CuS MF superstructure was investigated. Furthermore, the formation mechanism was studied based on XRD and FESEM observations by time and temperature dependent experiments during the formation of the MF structures. Furthermore, the electrochemical supercapacitance and methanol oxidation properties of the 3D CuS MF superstructures were also investigated. The CuS MF superstructures have demonstrated enhanced capacitance, with a maximum specific capacity of 438 F g(-1) at 3 mA cm(-2), and good cycling stability, retaining about similar to 87% of their capacitance after 2000 charge-discharge cycles as well as improved supercapacitor energy density without drop in power density. As a catalyst for methanol electro-oxidation, the CuS MF superstructures showed high current density (7.7 mA cm(-2)); high catalytic rate constant (1.01 x 10(6) cm(3) mol(-1) s(-1)) and good long-term stability.</P>

A novel CuS microflower superstructure based sensitive and selective nonenzymatic glucose detection

Radhakrishnan, S.,Kim, H.Y.,Kim, B.S. Elsevier Sequoia 2016 Sensors and actuators. B Chemical Vol.233 No.-

The design and fabrication of novel metal sulfides superstructures is crucial role for their application in electrochemical biosensor. Herein, we report the fabrication and testing of nonenzymatic glucose biosensor based on the use of CuS microflower (CuS MF) superstructure. The new CuS MF superstructure was prepared on a large scale through a facile solvothermal method without using any surfactants or templates. The morphology, surface property and crystal structure of the as-prepared CuS MF were characterized by FE-SEM, EDX and XRD. This CuS MF modified electrode showed a wide linear range (upto 5.4mM) with excellent sensitivity (1007μAmM<SUP>-1</SUP>cm<SUP>-2</SUP>) obtained at much lower potential (0.5V), fast response time (<4s), good anti-interference ability and outstanding long term stability during nonenzymatic electrochemical sensing of glucose. Further, the designed glucose sensor was applied to the determination of glucose in human blood serum sample with satisfactory result.

Evaluation of nonlinear optical parameters of TiN/PVA nanocomposite e A comparison between semi empirical relation and Z-Scan results

S. Divya,V.P.N. Nampoori,P. Radhakrishnan,A. Mujeeb 한국물리학회 2014 Current Applied Physics Vol.14 No.1

We report on the third order non linearity of TiN/PVA nanocomposites. Linear and nonlinear optical properties were studied from theoretical and experimental method. Theoretical method involved Tichy and Ticha relation pooled with generalised Miller’s rule. During the study dispersion of refractive index is analysed using the WempleeDi Domenico single oscillator model. Z-Scan was used as the experimental tool. The results derived from theoretical method deviated greatly from the experimental .We believe that such incongruity is due to the SPR property of the TiN nanoparticle whose SPR peak almost coincides with the irradiated laser wavelength.

Phytotoxic mechanisms of bur cucumber seed extracts on lettuce with special reference to analysis of chloroplast proteins, phytohormones, and nutritional elements

Lee, S.M.,Radhakrishnan, R.,Kang, S.M.,Kim, J.H.,Lee, I.Y.,Moon, B.K.,Yoon, B.W.,Lee, I.J. Academic Press 2015 Ecotoxicology and environmental safety Vol.122 No.-

Bioherbicides from plant extracts are an effective and environmentally friendly method to prevent weed growth. The present investigation was aimed at determining the inhibitory effect of bur cucumber seed extracts (BSE) on lettuce plant growth. Bur cucumber seeds were ground with water, and two different concentrations of seed extracts (10% and 20%) were prepared and applied to lettuce plants. Decreased plant height, number of leaves, leaf length, leaf width, anProd. Type: FTPd leaf area were found in lettuce exposed to BSE as compared with controls. A significant reduction in lettuce biomass was observed in 20% BSE-treated plants due to the presence of higher amounts of phenolic content in the extracts. Moreover, a significant inhibitory chemical, 2-linoleoyl glycerol, was identified in BSE extracts. The mechanism of plant growth inhibition was assayed in lettuce proteins by 2-dimensional electrophoresis (2-DE) and the LC-MS/MS method. In total, 57 protein spots were detected in plants treated with 20% BSE and control plants. Among these, 39 proteins were down-regulated and 18 proteins were up-regulated in plants exposed to 20% BSE as compared with controls. The presence of low levels of chlorophyll a/b binding protein and oxygen-evolving enhancer protein 1 in BSE-exposed plants reduced photosynthetic pigment synthesis and might be a reason for stunted plant growth. Indeed, the plant-growth stimulating hormone gibberellin was inhibited, and synthesis of stress hormones such as abscisic acid, jasmonic acid, and salicylic acid were triggered in lettuce by the effects of BSE. Uptake of essential nutrients, Ca, Fe, Mg, K, S, and Mo, was deficient and accumulation of the toxic ions Cu, Zn, and Na was higher in BSE-treated plants. The results of this study suggest that extracts of bur cucumber seeds can be an effective eco-friendly bioherbicide for weed control that work by inhibiting mechanisms of photosynthesis and regulating phytohormones and nutritional elements.

우빠니샤드 序說

라다하끄리슈난(S Radhakrishnan) 한국불교연구원 1993 佛敎硏究 Vol.10 No.-

Dissimilar metal study on C44300 tube to AA7075 -T651 tube plate with and without thread by FWTPET process

E. Radhakrishnan,L. A. Kumaraswamidhas,D. Muruganandam,S. Senthil Kumaran 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.5

Friction welding has vital industrial role in fabricating automobiles, aerospace, ship building, heat exchangers using similar, dissimilar and bi-metal of ferrous and non-ferrous metals at mass production level. In this study, admiralty brass C44300 tube and aluminium alloy AA7075 -T651, 6 mm thick tube plate were identified as base metals. Different joint surface area profile of with and without thread of different pitch values was chosen to study the mechanical properties and micro structures of these two base metals. 0.1 mm clearance was maintained between the AA7075-T651 tube plate and C44300 tube outer diameter to make friction welding. Taguchi’s L16 orthogonal array techniques were adopted for identifying the most significant ranking process parameters. Analysis of variance (ANOVA) has been used to analyze the input parameter contribution in terms of percentage. Genetic algorithm (GA) was used to access the suitable input parameter value to obtain effective joint strength in terms of hardness, compressive strength and microstructure formation in the interface of the joint. A Compression test (CT) was conducted to evaluate the level of compressive strength of the joint. Threaded profile pair with higher pitch value proved high compressive strength over unthreaded pair. Micro structure for base metal C44300 tube and AA7075-T651 tube plate, Heat affected zone (HAZ) and Weld zone (WZ) of the joint has been studied. Hardness of base metals, HAZ and WZ was measured by micro Vickers hardness tester and the observation shows that hardness at joint interface has been found to be higher in all pairs.

Novel MWCNT interconnected NiCo₂O₄ aerogels prepared by a supercritical CO₂ drying method for ethanol electrooxidation in alkaline media

Jayaseelan, S.S.,Ko, T.H.,Radhakrishnan, S.,Yang, C.M.,Kim, H.Y.,Kim, B.S. Pergamon Press ; Elsevier Science Ltd 2016 International journal of hydrogen energy Vol.41 No.31

<P>The design and development of an economic and highly active non-precious electrocatalyst for ethanol electro-oxidation is challenging due to expensiveness of the precursors as well as processes and non-Eco friendliness. In this study, a novel preparation of mesoporous NiCo2O4-MWCNT nanocomposite aerogels based on sol gel technique is proposed. Multiwall carbon nanotube (MWCNT)-supported NiCo2O4 nanocomposite aerogels as an efficient catalyst for the ethanol electro-oxidation is reported. The MWCNTs exhibit an interconnected fibrous network with uniform dispersion of NiCo2O4 nanoparticles. The effects of MWCNT concentration on the ethanol electro-oxidation of MWCNT/NiCo2O4 aerogels are studied. We found that using a proper loading of MWCNTs allowed us to reach higher current densities for the oxidation of ethanol in an alkaline media. The highly porous and fibrous MWCNT/NiCo2O4 aerogels are the promising electro-catalysts for the oxidation of a direct ethanol fuel cell. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</P>

Gibberellin secreting rhizobacterium, Pseudomonas putida H-2-3 modulates the hormonal and stress physiology of soybean to improve the plant growth under saline and drought conditions

Kang, S.M.,Radhakrishnan, R.,Khan, A.L.,Kim, M.J.,Park, J.M.,Kim, B.R.,Shin, D.H.,Lee, I.J. Gauthier-Villars ; Elsevier Science Ltd 2014 Vol. No.

The physiological changes in tolerant soybean plants under salt and drought stress conditions with Pseudomonas putida H-2-3 were investigated. A bacterial isolate H-2-3 was isolated from soil and identified as Pseudomonas putida H-2-3 by 16S rDNA sequences. The treatment of P. putida H-2-3 significantly increased the length, fresh and dry weight of shoot and chlorophyll content in gibberellins (GAs) deficient mutant Waito-c rice seedlings over the control, it might be the presence of GA<SUB>1</SUB>, GA<SUB>4,</SUB> GA<SUB>9</SUB> and GA<SUB>20.</SUB> The soybean plant growth was retarded in salt (120 mM sodium chloride) and drought (15% polyethylene glycol) stress conditions at 10 days treatments, while P. putida H-2-3 effectively enhanced the shoot length and fresh weight of plants suffered at salt and drought stress. The chlorophyll content was lower in abiotic stress conditions and bacterial inoculant P. putida H-2-3 mitigated the stress effects by an evidence of higher quantity of chlorophyll content in plants exposed to salt and drought. The stress hormonal analysis revealed that individual treatment of P. putida H-2-3, salt and drought significantly enhanced the abscisic acid and salicylic acid content than their control. P. putida H-2-3 applied to salt and drought stressed plants showed a lower level of abscisic acid and salicylic acid and a higher level of jasmonic acid content. Under stress condition induced by salt and drought in plants expressed higher level of total polyphenol, superoxide dismutase and radical scavenging activity and no significant changes in flavonoids. The bio-inoculant, P. putida H-2-3 modulated those antioxidants by declining superoxide dismutase, flavonoids and radical scavenging activity. P. putida H-2-3 induced tolerance against abiotic stress was confirmed by a reduction of Na content in abiotic stressed plants. The results suggest that P. putida H-2-3 application reprograms the chlorophyll, stress hormones and antioxidants expression in abiotic stress affected soybean plant and improves their growth under stress environment.

Analysis of Electrical and Thermal Conductivities of Polyethersulfone-Graphite Based Hybrid Nanocomposites

B. T. S. Ramanujam,S. Radhakrishnan,Shripad D. Deshpande 한국고분자학회 2017 Macromolecular Research Vol.25 No.4

Polyethersulfone (PES)-7 wt% graphite- x wt% filler (carbon black (CB), carbon nanofiber (CNF), expanded graphite (ExGr)) hybrid composites are synthesized by solution blending route. The electrical percolation threshold in hybrid composites varies exponentially with the aspect ratio of the second conducting filler. The aspect ratio of the second conducting filler has been found to vary in the order CB < CNF < ExGr. The percolation threshold is identified at 0.05 wt%, 0.4 wt%, 1.3 wt% for ExGr, CNF and CB added PES-7 wt% graphite composites. Through plane thermal conductivity of PES-x wt% graphite-y wt% CB (x=10, 20, 30, 40, 50, 60, y=0, 3, 7) hybrid composites has been found to increase with the addition of CB. Thermal conductivity has been increased to 0.42 W/m-K when 7 wt% CB is added to PES-60 wt% graphite from 0.2 W/m-K. Reduction of interparticular distance with the increased loading of CB facilitates better thermal transport. Aspect ratios of second conducting fillers have been found out from transmission electron microscopy and scanning electron microscopy analysis.

In-situ chemical oxidative polymerization of aniline monomer in the presence of cobalt molybdate for supercapacitor applications

Veerasubramani, G.K.,Krishnamoorthy, K.,Radhakrishnan, S.,Kim, N.J.,Kim, S.J. Korean Society of Industrial and Engineering Chemi 2016 Journal of industrial and engineering chemistry Vol.36 No.-

<P>A simple and green approach for the preparation of cobalt molybdate/polyaniline (CoMoO4/PANI) composite via in-situ polymerization method has been reported. The growth of PANI conductive layer on the surface of plate-like CoMoO4 nanostructures has been confirmed by XRD, FT-IR, Raman and FE-SEM techniques. The prepared CoMoO4/PANI composite delivered a maximum specific capacitance of 246 F/g at scan rate of 5 mV/s, whereas pristine PANI exhibits only 160 F/g which attributed to the synergic effect on the conducting network between CoMoO4 and PANI. The cyclic stability measurement revealed that above 80% of its initial capacitance is retained even after long cycles. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.</P>