Experimental investigations on composite slabs to evaluate longitudinal shear strength

Saravanan, M.,Marimuthu, V,Prabha, P.,Arul Jayachandran, S.,Datta, D. 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.13 No.5

Cold-formed steel profile sheets acting as decks have been popularly used in composite slab systems in steel structural works, since it acts as a working platform as well as formwork for concreting during construction stage and also as tension reinforcement for the concrete slab during service. In developing countries like India, this system of flooring is being increasingly used due to the innate advantage of these systems. Three modes of failure have been identified in composite slab such as flexural, vertical shear and longitudinal shear failure. Longitudinal shear failure is the one which is difficult to predict theoretically and therefore experimental methods suggested by Eurocode 4 (EC 4) of four point bending test is in practice throughout world. This paper presents such an experimental investigation on embossed profile sheet acting as a composite deck where in the longitudinal shear bond characteristics values are evaluated. Two stages, brittle and ductile phases were observed during the tests. The cyclic load appears to less effect on the ultimate shear strength of the composite slab.

Advanced analysis of cyclic behaviour of plane steel frames with semi-rigid connections

Saravanan, M.,Arul Jayachandran, S.,Marimuthu, V.,Prabha, P. 국제구조공학회 2009 Steel and Composite Structures, An International J Vol.9 No.4

This paper presents the details of an advanced Finite Element (FE) analysis of a plane steel portal frame with semi-rigid beam-to-column connections subjected cyclic loading. In spite of several component models on cyclic behaviour of connections presented in the literature, works on numerical investigations on cyclic behaviour of full scale frames are rather scarce. This paper presents the evolution of an FE model which deals comprehensively with the issues related to cyclic behaviour of full scale steel frames using ABAQUS software. In the material modeling, combined kinematic/isotropic hardening model and isotropic hardening model along with Von Mises criteria are used. Connection non-linearity is also considered in the analysis. The bolt slip which happens in friction grip connection is modeled. The bolt load variation during loading, which is a pivotal issue in reality, has been taken care in the present model. This aspect, according to the knowledge of the authors, has been first time reported in the literature. The numerically predicted results using the methodology evolved in the present study, for the cyclic behaviour of a cantilever beam and a rigid frame, are validated with experimental results available in the literature. The momentrotation and deflection responses of the evolved model, match well with experimental results. This proves that the methodology for evolving the steel frame and connection model presented in this paper is closer to real frame behaviour as evident from the good comparison and hence paves the way for further parametric studies on cyclic behaviour of flexibly connected frames.

Structural, electrochromic and FT-IR studies on electrodeposited tungsten trioxide films

R.Vijayalakshmi,M.Jayachandran,C.Sanjeeviraja 한국물리학회 2003 Current Applied Physics Vol.3 No.2, 3

Tungsten trioxide (WO3conductor and hence it has recently attracted much interest in the field of solid state ionics. When the intercalation of the film is taken in the cyclic voltammograms for various concentrations (0.1, 0.5 and 1.0 N) of H2SO4, the voltage is recorded for the peakcurrent. The powder X-ray diraction pattern is taken and the peaks are compared with the JCPDS values. It is found to be thetriclinic structure. The FT-IR spectra are taken for the WO3 lms electrodeposited at dierent deposition current densities (0.25,0.50, 0.65 and 0.75 mA/cm2temperature of the bath constant. The lm exhibits a broad peak from 3780 to 3500 cm. 1 which indicated the OHH stretchingvibration. The peak at 3543 cm. 1 depends upon the coloration increase in the electrodeposited tungsten trioxide lm. A littleamount of molecular water may exist in the electrodeposited WO3 lm, which corresponds to a broad peak at 2500 cm. 1. A smallpeak at 820 cm. 1 exhibits WO stretching. After ion intercalation the peak positions are slightly changed.

Development of a novel high speed (electron-mobility)epi-n-ZnO thin films by L-MBE for III-V opto-electronic devices

C.Sanjeeviraja,M.Jayachandran,K.Sankaranarayanan,Pankaj Misra,L.M.Kukreja,K.Ramamoorthy 한국물리학회 2004 Current Applied Physics Vol.4 No.6

Intrinsic epitaxial zinc oxide (epi-ZnO) thin lms were grown by laser-molecular beam epitaxy (L-MBE), i.e., pulsed laserdeposition (PLD) technique using Johnson Matthey ‘‘specpure’’-grade ZnO pellets. The eects of substrate temperatures on ZnOthin lm growth, electrical conductivity (r), mobility (l ) and carrier concentration (n) were studied. As well as the feasibility ofdeveloping high quality conducting oxide thin lms was also studied simultaneously. The highest conductivity was found foroptimized epi-ZnO thin lms isr ¼ 0:06 . 103 ohm. 1 cm. 1 (n-type) (which is almost at the edge of semiconductivity range), carrierdensityn ¼ 0:316 . 1019 cm. 3 and mobility l ¼ 98 cm2/Vs. The electrical studies further conrmed the semiconductor charac-teristics of epi-n-ZnO thin lms. The relationship between the optical and electrical properties were also graphically enumerated.The electrical parameter values for the lms were calculated, graphically enumerated and tabulated. As a novelty point of view, wehave concluded that without doping and annealing, we have obtained optimum electrical conductivity with high optical trans-parency (P 95%) for as deposited ZnO thin lms using PLD. Also, this is the rst time that we have applied PLD made ZnO thinlms to iso-, hetero-semiconductorinsulatorsemiconductor (SIS) type solar cells as transparent conducting oxide (TCO) windowlayer. We hope that surely these data be helpful either as a scientic or technical basis in the semiconductor processing

Characterization on electron beam evaporated α-MoO3 thin films by the influence of substrate temperature

R. Sivakumar,R. Gopalakrishnan,M. Jayachandran,C. Sanjeeviraja 한국물리학회 2007 Current Applied Physics Vol.7 No.1

Electrochromic molybdenum oxide (MoO3) thin lms were prepared by electron beam evaporation technique using the dry MoO3pellets. The lms were deposited on glass and uorine doped tin oxide (SnO2:F or FTO) coated glass substrates at dierent substratetemperatures like room temperature (RT, 30.C), 100.C and 200 .C. The inuence of substrate temperature on the structural, surfacerhombic phase MoO 3 (a-MoO3) withh110i preferred orientation. The laser Raman scattering spectrum shows the polycrystalline natureof MoO 3 lms deposited at 200.C. The Raman-active band at 993 cm. 1 is corresponding to MoO stretching mode that is associatedwith the unique character of the layered structure of orthorhombic MoO3. Needlelike morphology was observed from the SEM anal-ysis. The energy band gap of MoO3 lms was evaluated which lies between 2.8 and 2.3 eV depending on the substrate temperature andsubstrates. The decrease in band gap value with increasing substrate temperature is owing to the oxygen-ion vacancies. The absorptionedge shift shows the coloration eect on the lms.

Development of a novel high optical quality ZnO thin films by PLD for III-V opto-electronic devices

K. Ramamoorthy,C. Sanjeeviraja,M. Jayachandran,K. Sankaranarayanan,Pankaj Misra,L.M. Kukreja 한국물리학회 2006 Current Applied Physics Vol.6 No.1

pulsed laser deposition (PLD) technique using Johnson Matthey ‘‘specpure’’- grade ZnO pellets. The eects of substrate tempera-tures on zinc oxide thin lm growth, optical transmission, absorption, reection and photoluminescence properties were studied. Aswell as the feasibility of developing high quality transparent oxide thin lms was also studied simultaneously. The optical transmis-sion window of such obtained lms, i.e.,T% (max) P 95% is broader than those of other transparent conducting oxides such asto emphasize as a interesting, signicant and novel physical eect that the average optical transmittance of ZnO thin lms rivals thatof the most transmittive TCO lms reported to date for this conductivity level (of the order of 103 X. 1 cm. 1). Also this is the rsttime that we have applied these PLD prepared ZnO thin lms to iso and hetero semiconductorinsulatorsemiconductor (SIS) typereective coatings. From photoluminescence study, we conrmed the purity and high electrical conductivity of the deposited thinlms of ZnO. The optical parameter values for the lms were calculated, tabulated and graphically emphasized. Supplementarystudies on surface, electrical, structural and internal morphological properties of zinc oxide thin lm growth correlated with opticaltransmission, absorption, reection and photoluminescence properties gives added advantages to this work. We hope that surelythese data should be helpful either as a scientic or technical basis in the semiconductor processing and technology.

Micro-structural and optical properties of reactive magnetron sputtered Aluminum Nitride (AlN) nanostructured films

B. Subramanian,V. Swaminathan,M. Jayachandran 한국물리학회 2011 Current Applied Physics Vol.11 No.1

The materials properties of nanostructured Aluminum nitride (AlN) film were studied. AlN films of about 2 μm thick were deposited on Si (100) and glass substrates by means of direct current reactive magnetron sputtering in an Ar + N_2 gas mixture. A hexagonal wurtzite structure with a predominant peak was observed along the (002) plane from XRD analysis. Photoelectron peaks from Al, N, O, C and Ar are detected on the surface of the film. Microstructure and topography were analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The images showed the presence of continuously covered pebble like spherical grains on the surface. AlN films are transparent in the visible region with an average transmittance of 60%. The optical absorption studies give direct band gap equal to 5.2 eV.

Microstructural, Tribological and Electrochemical Corrosion Studies on Reactive DC Magnetron Sputtered Zirconium Nitride Films with Zr Interlayer on Steel

B. Subramanian,V. Swaminathan,M. Jayachandran 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.6

Thin films of Zirconium Nitride (ZrN) were deposited by DC magnetron sputtering. The structure of the films was examined by X-ray diffraction and the crystallographic parameters were refined by Rietveld analysis. The columnar micro-structure was observed via cross-sectional SEM analysis. Defect induced,first order spectra were observed from Laser Raman studies. XPS showed the presence of Zr (N,O) ZrO2phases on the surface of the film. The pitting corrosion was substantially reduced by the employment of Zr film as an interlayer. Corrosion tests revealed that ZrN films with a Zr interlayer exhibited clear passivation characteristics with considerably better corrosion resistance than the film without an interlayer.

An electrochromic device (ECD) cell characterization on electron beam evaporated MoO3 films by intercalating/deintercalating the H+ ions

R. Sivakumar,C.S. Gopinath,M. Jayachandran,C. Sanjeeviraja 한국물리학회 2007 Current Applied Physics Vol.7 No.1

Thin lms of molybdenum oxide (MoO3) is one of the most interesting layered intercalation materials because of its excellent appli-transmittance electrochromic devices (ECD) based on Li+, H+ and K+ intercalation in transition metal oxide (MoO3) thin lms. Inthe present investigation, thin lms of MoO3 were prepared by electron beam evaporation technique on microscopic glass and uorinedoped tin oxide (FTO) coated glass substrates for the application in electrochromic device cells. The compositional stoichiometry of the+ions from the H2SO4 electrolyte solution using the cyclic-voltammetry (CV) technique. We studied the electrochromic device cells (ECD)incorporating an evaporated MoO3 thin lms as electrochromic layers. The devices exhibit good optical properties with low transmit-tance values in the colored state, which make them suitable for large-area window applications. The maximum coloration eciencyof the cell was observed at about 70 cm2/C.

THE INFLUENCE OF SUBSTRATE TEMPERATURE ON THE ELECTRICAL PROPERTIES OF ZnO FILMS PREPARED BY THE RF MAGNETRON SPUTTERING TECHNIQUE

K. SARAVANAKUMAR,V. SENTHILKUMAR,C. SANJEEVIRAJA,M. JAYACHANDRAN,V. GANESAN,RAUSHAN B. KOIZHAIGANOVA,T. VASUDEVAN,MU SANG LEE 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2008 NANO Vol.3 No.6

ZnO thin films were grown by the RF magnetron sputtering technique at different substrate temperatures, from RT to 300°C. The crystallite size was calculated from XRD and the grain size was measured from AFM for different substrate temperatures. The influence of the substrate temperature on the electrical properties of the films was investigated through the Hall effect, and conductivity studies were performed under UV light illumination. The conductivity and the carrier mobility of the films were found to increase with increasing substrate temperature, which can be due to the grain-boundary-dominated conduction mechanism. The thermal activation energy and photosensitivity of the films were calculated, and the results are presented in this paper.