도시인 케리커쳐/공룡 , 도시의 25 시/「 멤포드 」는 현대도시인을 공룡이라 이름 짓는데(1970 년 5 권 9 호)

Edison 대한지방행정공제회 1970 도시문제 Vol.5 No.9

Supercapacitor performance of carbon supported Co₃O₄ nanoparticles synthesized using Terminalia chebula fruit

Edison, T.N.J.I.,Atchudan, R.,Sethuraman, M.G.,Lee, Y.R. Elsevier BV ; C/o Dept. of Chemical Engineering, N 2016 JOURNAL- TAIWAN INSTITUTE OF CHEMICAL ENGINEERS Vol.68 No.-

Carbon supported cobalt oxide nanoparticles (Co<SUB>3</SUB>O<SUB>4</SUB>Γ NPs) were synthesized by simple thermolysis of cobalt(II) acetate tetrahydrate and Terminalia chebula (T. chebula) fruit. The synthesized Co<SUB>3</SUB>O<SUB>4</SUB>Γ NPs were characterized using attenuated total reflection conjunction with Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) techniques. The specific surface area of Co<SUB>3</SUB>O<SUB>4</SUB>Γ NPs was measured by N<SUB>2</SUB> adsorption-desorption isotherm. The ATR-FTIR analysis revealed that the phytoconstituents of T. chebula were carbonized and supports the Co<SUB>3</SUB>O<SUB>4</SUB> NPs. The synthesized Co<SUB>3</SUB>O<SUB>4</SUB>Γ NPs were highly crystalline with carbon support, exposed by the XRD patterns. As inferred from microscopic images, the particle size of Co<SUB>3</SUB>O<SUB>4</SUB>Γ NPs is in the range of 15-25nm with distorted spherical shape. The EDS results confirmed the presence of three major elements such as Co, O and C in the synthesized Co<SUB>3</SUB>O<SUB>4</SUB>Γ NPs. The calculated specific surface area of Co<SUB>3</SUB>O<SUB>4</SUB> NPs is 22m<SUP>2</SUP>/g. The supercapacitor performance of synthesized Co<SUB>3</SUB>O<SUB>4</SUB>Γ NPs in 2M aqueous KOH was analyzed by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) methods. The Co<SUB>3</SUB>O<SUB>4</SUB>Γ NPs showed a maximum specific capacitance of about 642F/g at 1 A/g of discharging current density between 0 and 0.50V (vs. Ag/AgCl). The high specific capacitance of Co<SUB>3</SUB>O<SUB>4</SUB>Γ NPs could be attributed to the combination of both double layer capacitance and pseudocapacitance.

Ultrasonic synthesis, characterization and energy applications of Ni–B alloy nanorods

Edison, Thomas Nesakumar Jebakumar Immanuel,Atchudan, Raji,Karthik, Namachivayam,Sethuraman, Mathur Gopalakrishnan,Lee, Yong Rok Elsevier 2017 Journal of the Taiwan Institute of Chemical Engine Vol.80 No.-

<P><B>Abstract</B></P> <P>Alloy nanostructures had received much attention for their applications in energy, catalysis, and optics. This paper described a facile ultrasonic approach for the synthesis of Ni–B alloy nanorods (Ni–B NRs). The crystallinity, chemical state, surface area and surface morphology of Ni–B NRs were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N<SUB>2</SUB> adsorption–desorption isotherms and high-resolution transmission electron microscopy (HR–TEM) analyses, respectively. The electrocatalytic behavior of Ni–B NRs toward the oxygen evolution reaction (OER) was studied by linear sweep voltammetry (LSV) and Tafel polarization methods in 0.1 M aqueous KOH. The LSV results of Ni–B NRs showed very low OER onset potential of 1.44 V<SUB>RHE</SUB> with an overpotential of 212 mV<SUB>RHE</SUB>. The Ni–B NRs attained 10 mA/cm<SUP>2</SUP> of current density at a very low potential of 1.61 V<SUB>RHE</SUB> than bare SS (1.87 V<SUB>RHE</SUB>) and bare Pt (2.50 V<SUB>RHE</SUB>). Further, Ni–B NRs showed a low Tafel slope of 45 mV/dec when compared to other standard materials, revealed the fast OER kinetics. The calculated specific capacitance of synthesized Ni–B NRs was 581 F/g, from the results of cyclic voltammetry at a scan rate of 2 mV/s. The electrocatalytic and supercapacitor studies exposed that the synthesized Ni–B NRs can be used as an electrocatalyst for OER as well as pseudocapacitor for commercial electric vehicles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Amorphous Ni–B alloy nanorods (Ni–B NRs) are synthesized by ultrasonic method. </LI> <LI> Ni–B NRs shows excellent electrocatalytic activity toward OER than Ru and Ir. </LI> <LI> Ni–B NRs exhibit good pseudocapacitor behavior in aqueous KOH. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Binder-free electro-synthesis of highly ordered nickel oxide nanoparticles and its electrochemical performance

Edison, Thomas Nesakumar Jebakumar Immanuel,Atchudan, Raji,Lee, Yong Rok Elsevier 2018 ELECTROCHIMICA ACTA Vol.283 No.-

<P><B>Abstract</B></P> <P>In this work, highly ordered nickel oxide nanoparticles were electrochemically synthesized on nickel foam (NiO<SUB>x</SUB> NPs/Ni foam) via the formation and subsequent heat treatment of nickel hydroxide. The synthesized NiO<SUB>x</SUB> NPs were characterized using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) with elemental analysis and high resolution transmission electron microscopy (HR-TEM). The XRD results revealed the presence of two different oxide phases with high crystallinity. The synthesized NiO<SUB>x</SUB> NPs were highly ordered spherical morphology with average size of 7 nm, identified from the FE-SEM images. Further, the electrochemical performance of synthesized NiO<SUB>x</SUB> NPs/Ni foam was evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge discharge (GCD) methods. The calculated specific capacity of NiO<SUB>x</SUB> NPs/Ni foam was found to be 219 C/g (60.7 mAh/g) at scan rate of 5 mV/s. This present work implies that the electro-synthesized NiO<SUB>x</SUB> NPs/Ni foam as a good binder-free, highly stable battery-type material and it can be used as a positive electrode for hybrid-capacitors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Highly ordered NiO<SUB>x</SUB> nanoparticles were synthesized on Ni foam by cathodic electrodeposition. </LI> <LI> The average size of the NiO<SUB>x</SUB> NPs was about 7 nm with spherical shape. </LI> <LI> The electro-synthesized NiO<SUB>x</SUB> NPs shows good electrochemical performance in 2 M aqueous KOH. </LI> <LI> The NiO<SUB>x</SUB> NPs showed a maximum specific capacity of 219 C/g (60.7 mAh/g) at 5 mV/s. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Measurement of infinite dilution activity coefficients of selected environmentally important volatile organic compounds in polydimethylsiloxane using gas - liquid chromatography

Edison Muzenda,Mohamed Belaid,Freeman Ntuli 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.5

Silicon oil, chemically known as polydimethylsiloxane (PDMS), is a high boiling point solvent highly suitable for volatile organic compounds (VOCs) absorption. To use PDMS as an absorption solvent for a specific waste gas problem, it is important to determine the infinite dilution activity coefficients of the VOCs to be separated with PDMS. This work reports activity coefficients at infinite dilution of 13 VOCs in polydimethysiloxane determined by the dynamic gas liquid chromatographic technique. The measurements were carried out at various temperatures (303.15,313.15, 323.15., 333.15, 353.15, 373.15, 393.15 and 423.15 K). Four PDMS polymers with average molecular weight ranging from 760 to 13,000 were used as solvents. A control column packed by Perkin Elmer to our specifications was used to validate the coating and packing methods. Flow rate dependence of the elution peaks was also investigated by varying it from 10-50 ml/min. Precision was improved by reproducing the results using columns with different liquid loading, thus also studying the retention mechanism. The results compare well with the data from previous work using simple headspace and UNIFAC predictions and literature values. The successful comparison gives an indication of the GLC as a rapid, simple and accurate method for studying the thermodynamics of the interaction of a volatile solute with a nonvolatile solvent.

Corrosion inhibition performance of spermidine on mild steel in acid media

Edison, Thomas Nesakumar Jebakumar Immanuel,Atchudan, Raji,Pugazhendhi, Arivalagan,Lee, Yong Rok,Sethuraman, Mathur Gopalakrishnan Elsevier 2018 Journal of molecular liquids Vol.264 No.-

<P><B>Abstract</B></P> <P>The corrosion inhibition and adsorption behavior of spermidine on mild steel (MS) in 1 M sulfuric and 0.50 M hydrochloric acid have been investigated at room temperature by electrochemical methods viz., electrochemical impedance spectroscopy (EIS) and Tafel polarization techniques. The adsorption of spermidine on MS is studied by Langmuir adsorption isotherm, Fourier transform infrared (FT-IR) spectroscopy and density functional theory (DFT) analysis. The Tafel results imply that, spermidine behaves mixed mode inhibitor and the corrosion inhibition efficiency increases with increasing of spermidine concentration. The EIS results exposed that, the formation of adsorptive layer of spermidine increase the charge transfer resistance and subsequent drop in the double layer capacitance of MS in acids. The calculated free energy of adsorption (ΔG) for spermidine in HCl and H<SUB>2</SUB>SO<SUB>4</SUB> are −31.92 and −30.48 kJ mol<SUP>−1</SUP> which suggested the physical along with chemical mode of adsorption of inhibitor. The formation of inhibitive protection layer on MS is confirmed by FT-IR spectroscopy. The correlation of corrosion inhibition performance and molecular structure of spermidine is discussed by DFT method. All the results showed that spermidine is an excellent corrosion inhibitor for MS in both H<SUB>2</SUB>SO<SUB>4</SUB> and HCl acids.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The acid corrosion inhibition performance of spermidine on mild steel was evaluated. </LI> <LI> The spermidine act as mixed mode inhibitor revealed by Tafel studies. </LI> <LI> Spermidine adsorbed on mild steel and effectively retards corrosion. </LI> </UL> </P>

Direct electro-synthesis of MnO₂ nanoparticles over nickel foam from spent alkaline battery cathode and its supercapacitor performance

Edison, Thomas Nesakumar Jebakumar Immanuel,Atchudan, Raji,Karthik, Namachivayam,Xiong, Dangsheng,Lee, Yong Rok Elsevier 2019 JOURNAL- TAIWAN INSTITUTE OF CHEMICAL ENGINEERS Vol.97 No.-

<P><B>Abstract</B></P> <P>This work reports the recovery of manganese ions from spent primary alkaline battery (PAB) cathode, subsequent anodic electro-synthesis of MnO<SUB>2</SUB> nanoparticles on Ni foam (MnO<SUB>2</SUB> NPs/Ni foam) for supercapacitors. The as-fabricated MnO<SUB>2</SUB> NPs/Ni foam is characterized by common optical and surface analytical techniques. The X-ray diffraction (XRD) of MnO<SUB>2</SUB> NPs/Ni foam matches well with γ-MnO<SUB>2</SUB> NPs pattern and hence the synthesized MnO<SUB>2</SUB> NPs mainly exist in γ-phase. The synthesized MnO<SUB>2</SUB> NPs are mostly in spherical cluster shape with an average size of 15 nm, inferred from the scanning electron microscopic (SEM) images. The X-ray photoelectron spectroscopy (XPS) result reveals that, synthesized MnO<SUB>2</SUB> NPs embraces with two different oxidation states such as 4<SUP>+</SUP> (MnO<SUB>2</SUB>) and 3<SUP>+</SUP> (MnOOH). The MnO<SUB>2</SUB> NPs/Ni foam delivers a maximum specific capacity of 549 F/g at the scan rate of 5 mV/s in three electrodes aqueous K<SUB>2</SUB>SO<SUB>4</SUB> system. Further, the two electrode asymmetric supercapacitor device is constructed with MnO<SUB>2</SUB> NPs/Ni foam as a positive and commercial graphene nanoplatelets coated Ni foam (GNP/Ni foam) as a negative electrode. The assembled supercapacitor device yields a maximum specific capacitance of 105 F/g at 5 mV/s, which achieves a maximum energy density of 14.7 Wh/kg at the power density of 748.9 W/kg between 0 and 1.5 V of working potential. This effort may pave the way for recovery and utilization of spent PAB cathode materials for energy storage devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This work presents simple method for the recovery and utilization of Mn<SUP>2+</SUP> from spent alkaline battery cathode. </LI> <LI> The average size of the MnO<SUB>2</SUB> NPs was about 15 nm with spherical cluster shape. </LI> <LI> The electro-synthesized MnO<SUB>2</SUB> NPs revealed good electrochemical performance in K<SUB>2</SUB>SO<SUB>4</SUB>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Pulp revascularization with and without platelet-rich plasma in two anterior teeth with horizontal radicular fractures: a case report

Edison Arango-Gómez,Javier Laureano Nino-Barrera,Gustavo Nino,Freddy Jordan,Henry Sossa-Rojas 대한치과보존학회 2019 Restorative Dentistry & Endodontics Vol.44 No.4

Pulp revascularization is an alternative treatment in immature traumatized teeth with necrotic pulp. However, this procedure has not been reported in horizontal root fractures. This is a case report of a 9-year-old patient with multiple horizontal root fractures in 2 upper central incisors that were successfully treated with pulp revascularization. The patient presented for treatment 2 years after the initial trauma, and revascularization was attempted after the initial treatment with calcium hydroxide had failed. Prior to pulp revascularization, cone-beam computed tomography and autoradiograms demonstrated multiple horizontal fractures in the middle and apical thirds of the roots of the 2 affected teeth. Revascularization was performed in both teeth; platelet-rich plasma (PRP) was used in one tooth (#11) and the conventional method (blood clot) was used in the other tooth (#21). Clinical and radiographic follow-up over 4 years demonstrated pulp calcification in the PRP-treated tooth. Neither of the 2 teeth were lost, and the root canal calcification of tooth #11 was greater than that of tooth #21. This case suggests that PRP-based pulp revascularization may be an alternative for horizontal root fractures.

NaBH4 reduction of ortho and para-nitroaniline catalyzed by silver nanoparticles synthesized using Tamarindus indica seed coat extract

Edison, T. N.,Sethuraman, M. G.,Lee, Y. R. Springer Science + Business Media 2016 Research on chemical intermediates Vol.42 No.2

<P>This study deals with reduction of ortho and para-nitroaniline by NaBH4 with silver nanoparticles (AgNPs), synthesized by use of a green method, as catalyst. In the synthesis of the AgNPs an aqueous extract of Tamarindus indica (T. indica) seed coat was used as a reducing and capping agent. The effects of extract concentration and reaction time on formation of the AgNPs were studied by use of UV-visible (UV-Vis) spectroscopy. The stable AgNPs were characterized by dynamic light scattering (DLS), measurement of zeta potential, Fourier-transform infrared (FTIR) spectroscopy, and high-resolution transmission electron microscopy (HRTEM) with energy-dispersive spectrum analysis. Appearance of a yellow color and generation of a surface plasmon resonance peak in UV-Vis spectroscopy confirmed formation of the AgNPs. The FTIR results suggested that the phytoconstituents of T. indica seed coat extract are responsible for reduction of the Ag+ and protection of the AgNPs. HRTEM studies showed the size of the AgNPs was approximately 30-50 nm; their shape was distorted spherical. The TEM results were consistent with DLS study. The catalytic efficacy of stable AgNPs in the reduction of o and p-nitroaniline was studied by UV-Vis spectroscopy. The calculated rate constants (k) for catalytic reduction of o and p-nitroaniline by AgNPs were 2.43 x 10(-3) and 6.22 x 10(-3) S-1.</P>

Biogenic Synthesis of Silver Nanoparticles Using Cnidium officinale Extract and Their Catalytic Reduction of 4-Nitroaniline

Edison, Thomas Nesakumar Jebakumar Immanuel,Baral, Ek Raj,Lee, Yong Rok,Kim, Sung Hong Springer-Verlag 2016 Journal of cluster science Vol.27 No.1

<P>Silver nanoparticles (AgNPs) with two different morphologies were synthesized using aqueous extract of Cnidium officinale rhizomes under different reaction conditions and applied to the facile aqueous phase reduction of 4-nitroaniline (4-NA) as catalysts. The synthesized AgNPs are characterized by UV-Visible spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) method and high resolution transmission electron microscopy (HR-TEM) with energy dispersive X-ray spectroscopy (EDS) analysis. HR-TEM showed that the synthesized AgNPs had two different morphological forms; truncated triangular prism shapes with a mean size of similar to 35 nm and spherical shapes with a mean size of similar to 9 nm. The HR-TEM and XRD results are consistent with the standard values. The catalytic activities of both AgNPs were compared on the reduction of 4-NA in water by NaBH4 as a reducing agent. The reduction of 4-NA was monitored using UV-Visible spectroscopy. The similar to 9 nm (spherical) sized AgNPs showed superior catalytic activity than the larger AgNPs. The calculated rate constant (k) for the catalytic reduction of 4-nitroanilie by spherical AgNPs was 11.16 x 10(-3) s(-1).</P>