Experimental study on circular concrete filled steel tubes with and without shear connectors

K. Chithira,K. Baskar 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.16 No.1

This paper deals with a study on ultimate strength behaviour of eccentrically loaded CFT columns with and without shear connectors. Thirty specimens are subjected to experimental investigation under eccentric loading condition. P-M curves are generated for all the test specimens and critical eccentricities are evaluated. Three different D/t ratios such as 21, 25 and 29 and L/D ratios varying from 5 to 20 are considered as experimental parameters. Six specimens of bare steel tubes as reference specimens, twelve specimens of CFT columns without shear connectors and twelve specimens of CFT columns with shear connectors, in total thirty specimens are tested. The P-M values at the ultimate failure load of experimental study are found to be well agreed with the results of the proposed P-M interaction model. The load-deflection and load-strain behaviour of the experimental column specimens are presented. The behaviour of the CFT columns with and without shear connectors is compared. Experimental results indicate that the percentage increase in load carrying capacity of CFT columns with shear connectors compared to the ordinary CFT columns is found to be insignificant with a value ranging from 6% to 13%. However, the ductility factor of columns with shear connectors exhibit higher values than that of the CFT columns without shear connectors. This paper presents the proposed P-M interaction model and experimental results under varying parameters such as D/t and L/D ratios.

Application of Opposition-based Differential Evolution Algorithm to Generation Expansion Planning Problem

K. Karthikeyan,S. Kannan,S. Baskar,C. Thangaraj 대한전기학회 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 Oppositionbased 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.

Application of Opposition-based Differential Evolution Algorithm to Generation Expansion Planning Problem

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.

Combined Economic and Emission Dispatch with Valve-point loading of Thermal Generators using Modified NSGA-II

M. Rajkumar,K. Mahadevan,S. Kannan,S. Baskar 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.3

This paper discusses the application of evolutionary multi-objective optimization algorithms namely Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and Modified NSGA-II (MNSGA-II) for solving the Combined Economic Emission Dispatch (CEED) problem with valvepoint loading. The valve-point loading introduce ripples in the input-output characteristics of generating units and make the CEED problem as a non-smooth optimization problem. IEEE 57-bus and IEEE 118-bus systems are taken to validate its effectiveness of NSGA-II and MNSGA-II. To compare the Pareto-front obtained using NSGA-II and MNSGA-II, reference Pareto-front is generated using multiple runs of Real Coded Genetic Algorithm (RCGA) with weighted sum of objectives. Furthermore, three different performance metrics such as convergence, diversity and Inverted Generational Distance (IGD) are calculated for evaluating the closeness of obtained Pareto-fronts. Numerical results reveal that MNSGA-II algorithm performs better than NSGA-II algorithm to solve the CEED problem effectively.

Growth and characterization of neodymium and ytterbium doped barium chloride dihydrate single crystals

Kalidasan M.,Baskar K.,Dhanasekaran R. 한국물리학회 2016 Current Applied Physics Vol.16 No.9

Pure, Nd doped and Nd:Yb co-doped barium chloride dihydrate (BaCl2$2H2O) single crystals were grown and analyzed with various characterization techniques. The measured unit cell parameters show that the grown crystals belong to monoclinic system. Powder X-ray diffraction spectra indicates that the dopants enhance (2 1 0) orientation of BaCl2$2H2O crystal. X-ray rocking curves have been recorded to analyze the crystallinity of the grown single crystals. Optical absorption spectra of the grown crystals contain strong absorption bands in infrared region. Spectral overlap of absorption bands of Yb3þ and Nd3þ ion around 850 nme1060 nm in Nd:Yb co-doped single crystal indicates the prospect of energy transfer between them. A significant enhancement has been observed in the photoluminescence spectrum of Nd:Yb codoped single crystal recorded with 244 nm laser excitation. Photon upconversion ability of the crystals was tested using Nd:YAG laser of wavelength 1064 nm. An unusual upconverted green emission from pure centrosymmetric BaCl2$2H2O single crystal has been observed. The energy of upconverted green light of Nd:Yb co-doped barium chloride dihydrate single crystal is higher which may be due to energy transfer occurred between Yb3þ and Nd3þ ions. FTIR and FT-Raman spectral analyses were carried out to study the vibrational modes of pure, Nd doped and Nd:Yb co-doped BaCl2$2H2O single crystals.

Numerical study on thin plates under the combined action of shear and tensile stresses

Sathiyaseelan, S.,Baskar, K. Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.6

Analytical (Rayleigh-Ritz method) and numerical studies are carried out and buckling interaction curves are developed for simply supported plates of varying aspect ratios ranging from 1 to 5, under the combined action of in-plane shear and tension. A multi-step buckling procedure is employed in the Finite Element (FE) model instead of a regular single step analysis in view of obtaining the buckling load under the combined forces. Both the analytical (classical) and FE studies confirm the delayed shear buckling characteristics of thin plate under the combined action of shear and tension. The interaction curves are found to be linear and are found to vary with plate aspect ratio. The interaction curve developed using Rayleigh-Ritz method is found to deviate in an increasing trend from that of validated FE model as plate aspect ratio is increased beyond value of 1. It is found that the observed deviation is due to the insufficient number of terms that is been considered in the assumed deflection function of Rayleigh-Ritz method and a convergence study is suggested as a solution.

Numerical study on thin plates under the combined action of shear and tensile stresses

S. Sathiyaseelan,K. Baskar 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.6

Analytical (Rayleigh-Ritz method) and numerical studies are carried out and buckling interaction curves are developed for simply supported plates of varying aspect ratios ranging from 1 to 5, under the combined action of in-plane shear and tension. A multi-step buckling procedure is employed in the Finite Element (FE) model instead of a regular single step analysis in view of obtaining the buckling load under the combined forces. Both the analytical (classical) and FE studies confirm the delayed shear buckling characteristics of thin plate under the combined action of shear and tension. The interaction curves are found to be linear and are found to vary with plate aspect ratio. The interaction curve developed using Rayleigh-Ritz method is found to deviate in an increasing trend from that of validated FE model as plate aspect ratio is increased beyond value of 1. It is found that the observed deviation is due to the insufficient number of terms that is been considered in the assumed deflection function of Rayleigh-Ritz method and a convergence study is suggested as a solution.

Hydrothermal synthesis of chalcopyrite CuInS2, CuInSe2 and CuInTe2 nanocubes and their characterization

S. Sugan,K. Baskar,R. Dhanasekaran 한국물리학회 2014 Current Applied Physics Vol.14 No.11

CuInS2, CuInSe2 and CuInTe2 nanocubes of chalcopyrite structure have been successfully synthesized by hydrothermal process using deionized water as solvent at 180 C for 20 h. The crystallinity, compositional, morphological and optical properties of the synthesized samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), Raman and photoluminescence (PL) spectra analyses. The Raman spectra of the synthesized CuInS2, CuInSe2 and CuInTe2 samples show the dominant A1 modes at 293, 172 and 121 cm1 respectively. The possible chemical reaction and mechanism of nanocubes formation were discussed. The emission wavelength of as synthesized CuInS2, CuInSe2 and CuInTe2 samples were blue shifted at 746 nm (1.66 eV), 863 nm (1.43 eV) and 859 nm (1.44 eV) respectively.

NSGA-II Technique for Multi-objective Generation Dispatch of Thermal Generators with Nonsmooth Fuel Cost Functions

M. Rajkumar,K. Mahadevan,S. Kannan,S. Baskar 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.2

Non-dominated Sorting Genetic Algorithm-II (NSGA-II) is applied for solving Combined Economic Emission Dispatch (CEED) problem with valve-point loading of thermal generators. This CEED problem with valve-point loading is a nonlinear, constrained multi-objective optimization problem, with power balance and generator capacity constraints. The valve-point loading introduce ripples in the input-output characteristics of generating units and make the CEED problem as a nonsmooth optimization problem. To validate its effectiveness of NSGA-II, two benchmark test systems, IEEE 30-bus and IEEE 118-bus systems are considered. To compare the Pareto-front obtained using NSGA-II, reference Pareto-front is generated using multiple runs of Real Coded Genetic Algorithm (RCGA) with weighted sum of objectives. Comparison with other optimization techniques showed the superiority of the NSGA-II approach and confirmed its potential for solving the CEED problem. Numerical results show that NSGA-II algorithm can provide Pareto-front in a single run with good diversity and convergence. An approach based on Technique for Ordering Preferences by Similarity to Ideal Solution (TOPSIS) is applied on non-dominated solutions obtained to determine Best Compromise Solution (BCS).

Effect of low Cobalt doping on morphology and properties of calcium ferrite and its application as cathode in Solid Oxide Fuel Cell

Suchita Dhankhar,Pankaj Tiwari,K. Baskar,Suddhasatwa Basu,Shubra Singh 한국물리학회 2017 Current Applied Physics Vol.17 No.4

Cobaltite perovskites, such as polycrystalline complex brownmillerite oxide Ca2Fe2xCoxO5, possess high catalytic activity with potential application as cathode materials for Solid oxide fuel cells. However, high Co concentration can lead to high thermal expansion coefficient, which makes them incompatible with widely used Zirconia electrolytes. In the present work we employ low Co concentration and elucidate the effect of morphology on the physical properties of wet chemical synthesized Ca2Fe2xCoxO5 (x ¼ 0, 0.01, 0.03). Oxygen stoichiometry was determined from iodometry titration at room temperature. Co incorporation in the lattice, as low as 1 mol%, reveals a change in morphology and grain size.We also evaluate the role of Ca2Fe2xCoxO5 samples as cathode material in a bilayer (Cathode/Electrolyte) based on Ce0.9Sm0.1O2 (Samarium doped Ceria) solid electrolyte. Alternating Current (A.C) impedance spectroscopy showed variation in ionic conductivity with respect to temperature for Ca2Fe2xCoxO5 (x ¼ 0, 0.01, 0.03) in a temperature range from 400 C to 800 C. Activation energy with respect to Co-doping and temperature is reported. The complex impedance plane plots show a relaxed mechanism due to grain size effect. Scaling behavior of imaginary part of impedance indicates that relaxation follows similar mechanism at various temperatures.