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Arunkumar A.,Pondicherry Engineering College | Vanidha D.,Pondicherry Engineering College | Oudayakumar K.,Sri Manakula Vinayagar Engineering College | Rajagopan S.,Pondicherry Engineering College | Kannan R.,Pondicherry Engineering College
Journal of Applied Physics | Year: 2013

Variations in conductivity with particle size have been observed in cobalt ferrite, when synthesized by solgel auto-combustion method. Impedance analysis reveals metallic and semiconducting behavior at room temperature for a particle size of 6 nm and 52 nm, respectively. Upon thermal activation, metallic to semiconducting phase transition has been observed as a function of particle size and vice-versa. Grainboundary Resistance (Rgb), increased drastically with particle size (19 Mo for 6 nm and 259 Mo for 52 nm) at room temperature. AC conductivity and dielectric constants exhibit similar metallic to semiconducting phase transition at 6 nm and semiconducting behavior at 52 nm with temperature in the selected frequencies. Enhanced magnetic moment with an increase in the grain size along with decreased coercivity (1444 G to 1146 G) reveals transition from single domain to multi-domain. Increased inter-particle interaction is responsible for metallicity at the nano level and on the contrary semiconductivity is attributed to bulk. © 2013 AIP Publishing LLC. Source


Vijayshree J.C.,University | Palanivelu T.G.,Sri Manakula Vinayagar Engineering College
Proceedings of 2014 IEEE International Conference on Advanced Communication, Control and Computing Technologies, ICACCCT 2014 | Year: 2015

Nowadays due to the increase in demand for various multimedia services requiring high capacity, shortage of wireless resources becomes a serious problem in cellular networks. It is difficult to suddenly increase the capacity of wireless communication networks because of high cost and complexity. In order to increase the capacity of wireless communication networks with minor changes and low cost, internetworking is needed. The main objective of SIP is to support the upper layer and mobility management protocols to optimize the handover process between heterogeneous networks such as Ethernet, Bluetooth, Wi-Fi, WiMAX, 802.11 and various other networks. The basic purpose of the SIP standard is to facilitate between heterogeneous networks to provide seamless mobility. This standard also supports handover for the both mobile as well as stationary users. For mobile users, handover can occur when wireless link condition changes due to Mobile Node (MN) movement. In this proposed work, Vertical handover is implemented between WLAN and WiMAX networks by using Session initiation protocol and the performance metrics such as Network delay, Neighbour advertisements, Handover delay and throughput were obtained. © 2014 IEEE. Source


Meenakshisundaram S.P.,Annamalai University | Karthikeyan B.,Annamalai University | Muthu K.,Annamalai University | Sebastian S.,Sri Manakula Vinayagar Engineering College
Molecular Simulation | Year: 2013

The experimental and theoretical studies on the molecular structure and vibrational spectra of bis(thiourea)zinc(II) chloride (BTZC) crystals were investigated. The Fourier transform infrared, Fourier transform Raman and UV-vis spectra of BTZC were recorded. The molecular geometry and vibrational frequencies of BTZC in the ground state were calculated by using B3LYP with LANL2DZ as basis set. Comparison of the observed structural parameters of BTZC with single-crystal X-ray studies yields a good agreement. Vibrational analysis of the simultaneous IR and Raman activation of the Zn-Cl stretching mode in the molecule provides the evidence for the charge transfer interaction taking place within the molecule. The energy and oscillator strength are calculated by time-dependent density functional theory. The simulated spectra satisfactorily coincide with the experimental spectra. © 2013 Taylor & Francis. Source


Varalakshmi L.M.,Sri Manakula Vinayagar Engineering College | Florence S.G.,Pondicherry Engineering College
Multimedia Tools and Applications | Year: 2013

Encryption is one of the fundamental technologies that is used in the security of multimedia data. Unlike ordinary computer applications, multimedia applications generate large amount of data that has to be processed in real time. This work investigates the problem of efficient multimedia data encryption. A scheme known as the Randomized Huffman Table scheme was recently proposed to achieve encryption along with compression. Though this scheme has several advantages it cannot overcome the chosen plaintext attack. An enhancement of this Huffman scheme is proposed in this work which essentially overcomes the attack and improves the security. The proposed encryption approach consists of two modules. The first module is the Randomized Huffman Table module, the output of which is fed to the second XOR module to enhance the performance. Security analysis shows that the proposed scheme can withstand the chosen plaintext attack. The efficiency and security of the proposed scheme makes it an ideal choice for real time secure multimedia applications. © 2011 Springer Science+Business Media, LLC. Source


Jayavarthanan T.,Sri Manakula Vinayagar Engineering College | Sundaraganesan N.,Annamalai University | Karabacak M.,Afyonkocatepe University | Cinar M.,Afyonkocatepe University | Kurt M.,Ahi Evran University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

The solid phase FTIR and FT-Raman spectra of 2-amino-4-chloro-6- methylpyrimidine (2A4Cl6MP) have been recorded in the regions 400-4000 and 50-4000 cm-1, respectively. The spectra have been interpreted interms of fundamentals modes, combination and overtone bands. The structure of the molecule has been optimized and the structural characteristics have been determined by density functional theory (B3LYP) method with 6-311++G(d,p) as basis set. The vibrational frequencies were calculated and were compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. The infrared and Raman spectra have also been predicted from the calculated intensities. 1H and 13C NMR spectra were recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. UV-Vis spectrum of the compound was recorded in the region 200-400 nm and the electronic properties HOMO and LUMO energies were measured by time-dependent TD-DFT approach. Nonlinear optical and thermodynamic properties were interpreted. All the calculated results were compared with the available experimental data of the title molecule. © 2012 Elsevier B.V. All rights reserved. Source

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