Optimization of Drilling Characteristics for AI/SiC_p Composites Using Fuzzy/GA

Karthikeyan, R.,Jaiganesh, S.,Pai, B. C. 대한금속학회 2002 METALS AND MATERIALS International Vol.8 No.2

In this paper an attempt has been made to optimize the drilling characteristics for Al/SiCp composites using fuzzy logic and genetic algorithms (GA). The drilling characteristics studied were drill wear, specific energy and surface roughness. The parameters considered for the study include volume fraction of SiC in the aluminium matrix, cutting speed and feed rate. The experimental data was trained and simulated using fuzzy logic and optimization of cutting conditions were performed using genetic algorithms. The optimized cutting conditions were validated using confirmation experiments.

Facile synthesis of zinc oxide nanoparticles decorated graphene oxide composite via simple solvothermal route and their photocatalytic activity on methylene blue degradation

Atchudan, R.,Edison, T.N.J.I.,Perumal, S.,Karthikeyan, D.,Lee, Y.R. Elsevier Sequoia 2016 Journal of photochemistry and photobiology Biology Vol.162 No.-

Zinc oxide nanoparticles decorated graphene oxide (ZnO@GO) composite was synthesized by simple solvothermal method where zinc oxide (ZnO) nanoparticles and graphene oxide (GO) were synthesized via simple thermal oxidation and Hummers method, respectively. The obtained materials were thoroughly characterized by various physico-chemical techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Raman spectrum shows the intensity of D to G value was close to one which confirms the obtained GO and ZnO@GO composite possesses moderate graphitization. TEM images shows the ZnO nanoparticles mean size of 15+/-5nm were dispersed over the wrinkled graphene layers. The photocatalytic performance of ZnO@GO composite on degradation of methylene blue (MB) is investigated and the results show that the GO plays an important role in the enhancement of photocatalytic performance. The synthesized ZnO@GO composite achieves a maximum degradation efficiency of 98.5% in a neutral solution under UV-light irradiation for 15min as compared with pure ZnO (degradation efficiency is 49% after 60min of irradiation) due to the increased light absorption, the reduced charge recombination with the introduction of GO. Moreover, the resulting ZnO@GO composite possesses excellent degradation efficiency as compared to ZnO nanoparticles alone on MB.

Synthesis and characterization of graphitic mesoporous carbon using metal-metal oxide by chemical vapor deposition method

Atchudan, R.,Perumal, S.,Karthikeyan, D.,Pandurangan, A.,Lee, Y.R. Elsevier 2015 Microporous and mesoporous materials Vol.215 No.-

<P>Mn/MgO was prepared by wet impregnation method and was used as a catalytic template for the growth of graphitic mesoporous carbon (GMC) using acetylene gas as carbon precursor at 900 degrees C by CVD method. The deposited carbon nanostructured material was separated from the catalytic template by the acid treatment, and was investigated by various physico-chemical techniques such as XRD, BET, SEM, TEM, and Raman spectroscopy. The BET surface area of GMC is ca. 200 m(2) g(-1). The XRD pattern and Raman spectroscopic techniques revealed the crystallinity and the degree of graphitization of mesoporous carbon. The interlayer distance of graphene sheet in GMC is around 0.34 nm. All the analytical results strongly support that the prepared mesoporous carbon to be highly ordered and well in graphitic nature. Further, the results demonstrate that the GMC synthesized by using a Mn/MgO might be a promising contender for the large-scale synthesis. (C) 2015 Elsevier Inc. All rights reserved.</P>

A porous activated carbon supported Pt catalyst for the oxidative degradation of poly[(naphthaleneformaldehyde)sulfonate]

Karthikeyan, S.,Jo, Wan-Kuen,Dhanalakshmi, R.,Isaacs, Mark A.,Wilson, Karen,Sekaran, G.,Lee, Adam F. Elsevier 2018 JOURNAL- TAIWAN INSTITUTE OF CHEMICAL ENGINEERS Vol.93 No.-

<P><B>Abstract</B></P> <P>Wet catalytic oxidation of sodium poly[(naphthaleneformaldehyde)sulfonate], a hazardous contaminant of wastewater streams from the textiles industry, by hydrogen peroxide under ambient conditions was explored over platinum supported on a porous activated carbon (PAC). Bulk and surface properties of the Pt/PAC catalyst were investigated by XRD, XPS, SEM, TEM, FTIR, EPR and thermogravimetric analysis. The parent PAC, derived from pyrolysis and subsequent activation of rice husks, exhibited significant micro- and mesoporosity, and a high degree of surface oxidation. Incorporation of 1.7 wt% Pt resulted in mesopore blockage, and a corresponding drop in surface area, associated with the formation of large ∼8 nm metallic nanoparticles. Poly[(naphthaleneformaldehyde)sulfonate] oxidative degradation was studied as a function of reactant concentration and solution pH, revealing first order decomposition kinetics and good activity over pH 3–9 at ambient temperature. Electron Paramagnetic Resonance (EPR)-DMPO spin trapping experiments confirm that oxidation of the organic pollutant proceeded via hydroxyl radical generation. The 1.7 wt% Pt/PAC catalyst showed excellent catalyst stability for five consecutive runs over 25 h in a fluidised bed reactor, delivering > 85% removal of 100 mg/L sulfonate with negligible Pt leaching or activity loss, and comparable performance for treatment of a real tannery effluent stream with a COD equivalent of 1860 mg/L.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A facile route to Pt functionalized biogenically sourced porous activated carbon. </LI> <LI> First heterogeneous catalyst for poly[(naphthaleneformaldehyde)sulfonate] oxidation. </LI> <LI> Excellent activity and stability over a broad concentration and pH range. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

ACC deaminase containing diazotrophic endophytic bacteria ameliorate salt stress in Catharanthus roseus through reduced ethylene levels and induction of antioxidative defense systems

Karthikeyan, B.,Joe, M. M.,Islam, M. R.,Sa, T. INTERNATIONAL SCIENCE SERVICES ZEIST 2012 Symbiosis Vol.56 No.2

Influence of Switchgrass Generated Producer Gas Pre-adaptation on Growth and Product Distribution of Clostridium ragsdalei

Karthikeyan D. Ramachandriya,Mark R. Wilkins,Krushna N. Patil 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.6

Gasification-fermentation is a thermo chemicalbiologicalprocess for the production of fuels and chemicals. Producer gas cleanup is a major issue that must beaddressed for integration of these platforms. Pre-adaptationof producer gas fermenting microbes to gas impurities hasimproved tolerances to impurities and production of alcoholsin certain bacteria. In this research, the effect of switchgrassgenerated producer gas was studied with adapted andunadapted cultures of C. ragsdalei and compared tofermentations with a control of clean custom producer gas. Results indicated no inhibition to microbial growth withunadapted cells and final cell mass concentrations were22% higher when cells were exposed to switchgrass-basedproducer gas compared to control. The ethanol productivitywith adapted cells was 1.9 and 2.8 times higher thanunadapted and control treatments, respectively. Similarly,the ethanol yield (YETOH/X) of C. ragsdalei adapted toproducer gas was 119% more than the control and 35%greater than the unadapted cells used in this study. Thepresence of switchgrass-based producer gas also inducedmetabolic shifts resulting in reduction of acetic acid toethanol that increased ethanol to acetate ratios from 0.7 g/gin control to 4.9 g/g with unadapted cells and 13.7 g/g withadapted cells. Isopropanol was also observed as a productwhen switchgrass generated producer gas was used. Weconclude that cultural adaptation of C. ragsdalei to biomassgenerated producer gas during preculture stages could beused as an important strategy to enhance ethanol yields forintegrating gasification and fermentation platforms usingC. ragsdalei.

On-demand generation of heat and free radicals for dual cancer therapy using thermal initiator- and gold nanorod-embedded PLGA nanocomplexes

Guru Karthikeyan Thirunavukkarasu,G.R. Nirmal,이황재,이민규,박인규,이재영 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.69 No.-

Dual cancer therapy is an attractive strategy that can generate synergistic effects and also reduce drug-related side effects. Here, we developed multifunctional nanocomplexes capable of remote on-demand production of hyperthermia and free radicals in response to near infrared (NIR) light irradiation To this end, thermal initiator and gold nanorods were embedded in nano-sized temperature-responsive poly(lactic acid-co-glycolic acid). In vitro studies demonstrated controllable heat and radical production from the nanocomplexes with NIR and effective eradication of CT26 colon cancer cells with our nanocomplexes. Hence, our smart nanomaterial will potentially contribute precise and effective dual cancer treatment.

Three dimensional electro catalytic oxidation of aniline by boron doped mesoporous activated carbon

S. Karthikeyan,K. Viswanathan,R. Boopathy,P. Maharaja,G. Sekaran 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

In this report, boron doped mesoporous activated carbon (B-MAC) was synthesized by directhydrothermal route. The prepared B-MAC was characterized for HR-TEM, wide-angle XRD, SEM, XPS,FTIR and N2 sorption analyses. The results suggested that the B-MAC is mesoporous in structure andamorphous in nature, with surface area of 3.036 m2 g 1. The B-MAC was chosen as a catalyst for theelectrochemical oxidation of synthetic aniline solution. For the oxidations process, graphite rod waschosen as anode; SS 316 was chosen as cathode in the electrochemical catalytic oxidation process. Theelectro chemical oxidation of aqueous aniline solution was confirmed through UV–visible spectroscopy,Florescence emission spectrum and cyclic voltammetry analyses. The results revealed that, the removalefficiency of COD and aniline by B-MAC was found to be 76–80% and 80–85%, respectively, in electrocatalytic oxidation. MAC fluidized electro catalytic oxidation system removed COD by 40–45% andaniline by 50–62%, respectively. Thus, the B-MAC catalyst was found to be viable for the electrochemicaltreatment of aniline containing waste water.

Dimension Tolerances in Fabrication of Polymer Microfluidic Devices

K. Karthikeyan,L. Sujatha,R. Sundar,S. K. Sharma 대한전자공학회 2018 Journal of semiconductor technology and science Vol.18 No.2

In this paper, we discuss about critical issues in fabrication of polymer microfluidic devices which affect the dimensions of the microchannel and hence the volumetric analysis of the fluids. The optical and thermal properties of the materials used in the fabrication of devices determine the final structural dimensions and the reliability of the fabricated devices. A clear understanding of material properties and their effect on the dimensional variations of microfluidic devices during fabrication are essential in different applications such as micro dispensers, micro pump, micro mixers and micro reactors. It is possible to obtain microfluidic devices with perfect dimensions by carrying out the fabrication processes with perfect timing control and precisely controlled temperature during fabrication. This paper focuses on the dimensional stability of SU8 prime mould with respect to UV exposure time, effect of temperature on PDMS replicas and the effective sealing of the device by adhesive bonding.

Reactive Power Control and Neutral Current Elimination of Four Wire Five Level NPC Inverter based STATCOM using 3D-SVPWM Technique

Palanisamy R.,Karthikeyan D.,Vidyasagar S.,Kalyanasundaram V.,Selvakumar K.,Vijayakumar K.,Selvabharathi D. 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4

In this paper, three phase four wire fi ve level Neutral Point Clamped Inverter (NPCI) based Static synchronous Compensator (STATCOM) is implemented for reactive power control and neutral current elimination. Three dimensional Space Vector Pulse Width Modulation (3D-SVPWM) control strategy is developed to control this 5-level NPC inverter. The behaviour of static synchronous compensator is analyzed and reactive power control is done using constant DC voltage. The objective of this compensating method is to provide balanced and sinusoidal source currents under unbalanced and nonlinear load conditions and reactive power control. The 3D-SVPWM technique provides reduced harmonic content in output voltage and current, controlled source current, minimized common mode voltage and improved output voltage. In 3D-SVPWM, switching pulses are generated with non-redundant switching states, which lead to reduce the complexity in switching time calculation and computational time is less. The highlights of the paper includes the neutral current is reduced to 0.25A, source current harmonics is minimized and it provides balanced and sinusoidal source currents with help of STATCOM compensation. The simulation and experimental results demonstrates the sinusoidal and harmonics free source current and minimized neutral current for four wire fi ve level NPCI based STATCOM.