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V. Jayaprakash Narayanan,B. Karthik,S. Chandrasekar 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.4
Flashover of power transmission line insulators is a major threat to the reliable operation of power system. This paper deals with the flashover prediction of polymeric insulators used in power transmission line applications using the novel condition monitoring technique developed by PD signal time-frequency map and neural network technique. Laboratory experiments on polymeric insulators were carried out as per IEC 60507 under AC voltage, at different humidity and contamination levels using NaCl as a contaminant. Partial discharge signals were acquired using advanced ultra wide band detection system. Salient features from the Time-Frequency map and PRPD pattern at different pollution levels were extracted. The flashover prediction of polymeric insulators was automated using artificial neural network (ANN) with back propagation algorithm (BPA). From the results, it can be speculated that PD signal feature extraction along with back propagation classification is a well suited technique to predict flashover of polymeric insulators.
Narayanan, V. Jayaprakash,Sivakumar, M.,Karpagavani, K.,Chandrasekar, S. The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.5
Major problem in the high voltage power transmission line is the flashover due to polluted ceramic insulators which leads to failure of equipments, catastrophic fires and power outages. This paper deals with the development of a better diagnostic tool to predict the flashover and pollution severity of power transmission line insulators based on the wavelet transform and fuzzy c-means clustering approach. In this work, laboratory experiments were carried out on power transmission line porcelain insulators under AC voltages at different pollution conditions and corresponding leakage current patterns were measured. Discrete wavelet transform technique is employed to extract important features of leakage current signals. Variation of leakage current magnitude and distortion ratio at different pollution levels were analyzed. Fuzzy c-means algorithm is used to cluster the extracted features of the leakage current data. Test results clearly show that the flashover and pollution severity of power transmission line insulators can be effectively realized through fuzzy clustering technique and it will be useful to carry out preventive maintenance work.
Narayanan, V. Jayaprakash,Karthik, B.,Chandrasekar, S. The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.4
Flashover of power transmission line insulators is a major threat to the reliable operation of power system. This paper deals with the flashover prediction of polymeric insulators used in power transmission line applications using the novel condition monitoring technique developed by PD signal time-frequency map and neural network technique. Laboratory experiments on polymeric insulators were carried out as per IEC 60507 under AC voltage, at different humidity and contamination levels using NaCl as a contaminant. Partial discharge signals were acquired using advanced ultra wide band detection system. Salient features from the Time-Frequency map and PRPD pattern at different pollution levels were extracted. The flashover prediction of polymeric insulators was automated using artificial neural network (ANN) with back propagation algorithm (BPA). From the results, it can be speculated that PD signal feature extraction along with back propagation classification is a well suited technique to predict flashover of polymeric insulators.
V.Jayaprakash Narayanan,M.Sivakumar,K.Karpagavani,S.Chandrasekar 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.5
Major problem in the high voltage power transmission line is the flashover due to polluted ceramic insulators which leads to failure of equipments, catastrophic fires and power outages. This paper deals with the development of a better diagnostic tool to predict the flashover and pollution severity of power transmission line insulators based on the wavelet transform and fuzzy c-means clustering approach. In this work, laboratory experiments were carried out on power transmission line porcelain insulators under AC voltages at different pollution conditions and corresponding leakage current patterns were measured. Discrete wavelet transform technique is employed to extract important features of leakage current signals. Variation of leakage current magnitude and distortion ratio at different pollution levels were analyzed. Fuzzy c-means algorithm is used to cluster the extracted features of the leakage current data. Test results clearly show that the flashover and pollution severity of power transmission line insulators can be effectively realized through fuzzy clustering technique and it will be useful to carry out preventive maintenance work.
Rekharsky, Mikhail V.,Yamamura, Hatsuo,Mori, Tadashi,Sato, Akihiro,Shiro, Motoo,Lindeman, Sergey V.,Rathore, Rajendra,Shiba, Kouhei,Ko, Young Ho,Selvapalam, Narayanan,Kim, Kimoon,Inoue, Yoshihisa WILEY-VCH Verlag 2009 Chemistry Vol.15 No.8
<P>Water seeds: Complex stoichiometry/composition and degree of oligomerization (oligomeric supramolecular complex formation) of cucurbit[6]uril (CB[6]) with N-alkyl- and N,N′-dialkylpiperazine were investigated in aqueous solutions by means of isothermal titration calorimetry (ITC), ESI-MS, NMR and light scattering measurements. <img src='wiley_img/09476539-2009-15-8-CHEM200800398-content.gif' alt='wiley_img/09476539-2009-15-8-CHEM200800398-content'> </P><P>Complex stoichiometry/composition and degree of oligomerization (oligomeric supramolecular complex formation) of cucurbit[6]uril (CB[6]) with N-alkyl- and N,N′-dialkylpiperazine were investigated in aqueous solutions by means of isothermal titration calorimetry (ITC), ESI-MS, NMR and light scattering measurements. It was found that the complex stability and the degree of oligomerization increase with elongating the alkyl chain attached to the piperazine core. X-ray crystallographic studies revealed a clear correlation between the structure of CB[6]–alkylpiperazine crystals obtained from aqueous solutions and the molecular weight/properties of host–guest oligomers existed in the solution as supramolecular “seeds” of crystal formation.</P> <B>Graphic Abstract</B> <P>Water seeds: Complex stoichiometry/composition and degree of oligomerization (oligomeric supramolecular complex formation) of cucurbit[6]uril (CB[6]) with N-alkyl- and N,N′-dialkylpiperazine were investigated in aqueous solutions by means of isothermal titration calorimetry (ITC), ESI-MS, NMR and light scattering measurements. <img src='wiley_img/09476539-2009-15-8-CHEM200800398-content.gif' alt='wiley_img/09476539-2009-15-8-CHEM200800398-content'> </P>
A. Vijayaraj,R. Prabu,R. Suresh, L. Jagadish,R. Sangeetha Kumari,V. Kaviyarasan,V. Narayanan 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.11
A new series of acyclic mononuclear gadolinium(III) complexes have been prepared by Schiff-base condensation derived from 5-methylsalicylaldehyde, diethylenetriamine, tris(2-aminoethyl) amine, triethylenetetramine, N,N-bis(3-aminopropyl)ethylene diamine, N,N-bis(aminopropyl) piperazine, and gadolinium nitrate. All the complexes were characterized by elemental and spectral analyses. Electronic spectra of the complexes show azomethine (CH=N) within the range of 410-420 nm. The fluorescence efficiency of Gd(III) ion in the cavity was completely quenched by the higher chain length ligands. Electrochemical studies of the complexes show irreversible one electron reduction process around −2.15 to −1.60 V The reduction potential of gadolinium(III) complexes shifts towards anodic directions respectively upon increasing the chain length. The catalytic activity of the gadolinium(III) complexes on the hydrolysis of 4-nitrophenylphosphate was determined. All gadolinium(III) complexes were screened for antibacterial activity.
Vijayaraj, A.,Prabu, R.,Suresh, R.,Kumari, R. Sangeetha,Kaviyarasan, V.,Narayanan, V. Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.11
A new series of acyclic mononuclear gadolinium(III) complexes have been prepared by Schiff-base condensation derived from 5-methylsalicylaldehyde, diethylenetriamine, tris(2-aminoethyl) amine, triethylenetetramine, N,N-bis(3-aminopropyl)ethylene diamine, N,N-bis(aminopropyl) piperazine, and gadolinium nitrate. All the complexes were characterized by elemental and spectral analyses. Electronic spectra of the complexes show azomethine (CH=N) within the range of 410-420 nm. The fluorescence efficiency of Gd(III) ion in the cavity was completely quenched by the higher chain length ligands. Electrochemical studies of the complexes show irreversible one electron reduction process around -2.15 to -1.60 V The reduction potential of gadolinium(III) complexes shifts towards anodic directions respectively upon increasing the chain length. The catalytic activity of the gadolinium(III) complexes on the hydrolysis of 4-nitrophenylphosphate was determined. All gadolinium(III) complexes were screened for antibacterial activity.
Giribabu, K.,Haldorai, Y.,Rethinasabapathy, M.,Jang, S.C.,Suresh, R.,Cho, W.S.,Han, Y.K.,Roh, C.,Huh, Y.S.,Narayanan, V. ELSEVIER 2017 CURRENT APPLIED PHYSICS Vol.17 No.8
<P>In this study, poly(methyl orange) (PMO) was synthesized by electrodeposition onto a glassy carbon electrode (GCE), and the resulting structure was examined for the determination of 4-nitrophenol (4-NP). Cyclic voltammetry revealed that the PMO-modified GCE (PMO/GCE) exhibited excellent electrocatalytic activity for the oxidation of 4-NP in a 0.5-M phosphate buffer solution. In contrast, the bare GCE showed no oxidation peak. Interestingly, PMO/GCE exhibited an oxidation peak at approximate 0.93 V, and the background current was higher than that of the bare GCE. Furthermore, the developed electrochemical sensor exhibited a linear relationship with the 4-NP concentration from 600 nM to 10 mu M, and the limit of detection was 170 nM (signal/noise = 3). The sensor demonstrated excellent selectivity, good stability, and reproducibility. It was applied to the determination of 4-NP in water samples by the standard addition method and gave recoveries of 99.2-100.9%. (C) 2017 Elsevier B.V. All rights reserved.</P>
V. Vinod,Bipin Balaram,M. D. Narayanan,Mihir Sen 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.5
This paper investigates the dynamical behavior of coupled van der Pol oscillators in a ring to understand vibrations that may occur insystems such as turbine blades mounted on a single shaft. The objective is to investigate the effect of spatial differences in oscillator parametersand initial conditions that occur in realistic systems. The coupling between the neighboring oscillators is modeled as a lineardissipative element, and the mathematical model is analyzed asymptotically and numerically. Synchronization of self excited oscillatorsin mechanical systems has been predominantly investigated in recent literature by focusing on its parameter dependence. This work investigatesthe dependence of dynamics of such systems on initial conditions. The analysis is conducted for identical oscillators as well asoscillators with a frequency mismatch, along with three different sets of initial conditions. The dynamics of the system is discussed basedon time plots, frequency plots, instantaneous dynamics of each oscillator by Hilbert transform and the phase equation obtained by asymptoticexpansion. The study reveals interesting phenomena like amplitude death, oscillation suppression, oscillation resurrection, frequencylocking and beat frequency in the model when subjected to the different set of initial conditions.