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A Simulation Tool for Ultrasonic Inspection
Krishnamurthy, Adarsh,Mohan, K.V.,Karthikeyan, Soumya,Krishnamurthy, C.V.,Balasubramaniam, Krishnan The Korean Society for Nondestructive Testing 2006 한국비파괴검사학회지 Vol.26 No.3
A simulation program SIMULTSONIC is under development at CNDE to help determine and/or help optimize ultrasonic probe locations for inspection of complex components. SIMULTSONIC provides a ray-trace based assessment for immersion and contact modes of inspection. The code written in Visual C++ operating in Microsoft Windows environment provides an interactive user interface. In this paper, a description of the various features of SIMULTSONIC is given followed by examples illustrating the capability of SIMULTSONIC to deal with inspection of canonical objects such as pipes. In particular, the use of SIMULTSONIC in the inspection of very thin-walled pipes (with 450 urn wall thickness) is described. Ray trace based assessment was done using SIMULTSONIC to determine the standoff distance and the angle of oblique incidence for an immersion mode focused transducer. A 3-cycle Hanning window pulse was chosen for simulations. Experiments were carried out to validate the simulations. The A-scans and the associated B-Scan images obtained through simulations show good correlation with experimental results, both with the arrival time of the signal as well as with the signal amplitudes.
Optimization of active area of proton exchange membrane fuel cell with better water management
M. Karthikeyan,M. Muthukumar,P. Karthikeyan,C. Mathan 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.5
Water flooding is one of the major issues which is influencing the performance of PEMFC, while scaling up the active area. Water accumulation in between the GDL and cathode flow field landing in PEMFC can be removed by fixing porous inserts along the landing area of the cathode flow field. In this paper, the optimum active area of the PEMFC is found from the experimental investigations of three active area sizes of 25 cm2, 36 cm2 and 70 cm2 with better water management by fixing porous inserts along the landing surface. All three active areas of PEMFCs with three different flow fields viz. Serpentine; Uniform and Stagger patterned pin types having porous inserts on cathode side have been investigated experimentally. The PEMFCs with active area of 25 cm2, 36 cm2 and 70 cm2 with stagger patterned pin types having porous inserts have obtained maximum power densities as 0.270 W/cm2, 0.338 W/cm2and 0.170 W/cm2 respectively. The PEMFC with active area of 36 cm2 yields higher power density compared to 25 cm2 and 70 cm2 PEMFCs. So it is found that the active area of 36 cm2 is the optimum active area of single cell PEMFC for maximum performance.
Investigations on Doping of Poly(3-methyl-thiophene) Composites for Supercapacitor Applications
G. Karthikeyan,S. Sahoo,G. C. Nayak,C. K. Das 한국고분자학회 2012 Macromolecular Research Vol.20 No.4
Zinc ion (Zn2+)-doped poly(3-methyl-thiophene)/multi-walled carbon nano tubes (MWCNT) composites (M-PMT-ZN) and poly(3-methyl-thiophene)/MWCNT composites (M-PMT) were synthesized by in situ chemical oxidative polymerization and investigated as electrode material for supercapacitors. The interactions of Zn2+ ions with sulfur sites on the polymer chains were characterized by Fourier transform infrared spectroscopy. The morphology of the nanocomposites was characterized by scanning electron microscopy and high resolution transmission electron microscopy. The electrochemical properties were investigated using cyclic voltammetry, cyclic chargingdischarging tests, and electrochemical impedance spectroscopy in a three-electrode system. Use of M-PMT-ZN resulted in a higher specific capacitance of 235 F/g. The specific capacitance retention after 500 cycles on M-PMTZN was also higher compared with that of the M-PMT composite. These results indicate that transition metal ion doping enhances the electrochemical properties of the conducting polymer.
Karthikeyan, K.,Kannan, S.,Baskar, S.,Thangaraj, C. The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.4
Generation Expansion Planning (GEP) is one of the most important decision-making activities in electric utilities. Least-cost GEP is to determine the minimum-cost capacity addition plan (i.e., the type and number of candidate plants) that meets forecasted demand within a pre specified reliability criterion over a planning horizon. In this paper, Differential Evolution (DE), and Opposition-based Differential Evolution (ODE) algorithms have been applied to the GEP problem. The original GEP problem has been modified by incorporating Virtual Mapping Procedure (VMP). The GEP problem of a synthetic test systems for 6-year, 14-year and 24-year planning horizons having five types of candidate units have been considered. The results have been compared with Dynamic Programming (DP) method. The ODE performs well and converges faster than DE.
KARTHIKEYAN, K.,CHANDRAN, C.,TRUJILLO, J.J. The Korean Society for Computational and Applied M 2016 Journal of applied mathematics & informatics Vol.34 No.3
In this paper, we study boundary value problems for fractional integrodifferential equations involving Caputo derivative in Banach spaces. A generalized singular type Gronwall inequality is given to obtain an important priori bounds. Some sufficient conditions for the existence solutions are established by virtue of fractional calculus and fixed point method under some mild conditions.