Tiruchirappalli, India
Tiruchirappalli, India

Bishop Heber College is a Christian educational institution in Tiruchirappalli, Tamil Nadu, India. It was founded in 1966, although the school has historical roots extending through various earlier local religious schools to about the mid-nineteenth century. Wikipedia.

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Sivasankar V.,Thiagarajar College of Engineering | Ramachandramoorthy T.,Bishop Heber College | Chandramohan A.,Bishop Heber College
Journal of Hazardous Materials | Year: 2010

The present work is concerned with the defluoridation capacities of activated (ATFS) and MnO2-coated Tamarind Fruit Shell (MTFS), using batch and column sorption techniques. In the batch technique, the dynamics of fluoride sorption, with respect to pH, [F]o and sorbent dose, was studied. The applicability of pseudo-first order for ATFS and Ritchie-second order for MTFS was observed. The kinetics data were found to fit well with Temkin isotherm for ATFS and Langmuir for MTFS. The interaction of co-ions in the defluoridation capacity of the sorbent was studied. Column experiments were carried out under a constant fluoride concentration of 2mg/l, flow rate and different bed depths. The capacities of the breakthrough and exhaustion points increased with increase in the bed depth for ATFS unlike MTFS. The Thomson model was applied to the column experimental results. The characterization of the sorbents, ATFS and MTFS, was done using the FTIR, SEM and XRD techniques. © 2009 Elsevier B.V.

Vijayalakshmi K.,Bishop Heber College | Pillay V.V.,Sujatha Degree and PG College for Women
Microelectronic Engineering | Year: 2014

Thin films of aluminum nitride (AlN) were prepared on Si (1 0 0) substrate by dc reactive magnetron sputtering. The influence of sputter deposition time on the properties of the AlN films was studied. The films were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR) and Scanning Electron Microscope. Dielectric properties of the film were investigated using impedance analyzer. XRD measurements showed the presence of hexagonal wurtzite structure. The crystal orientation of the AlN films changed from (1 0 0) to (0 0 2) with increase in deposition time. The peak found in FTIR spectra was attributed to A1 (To) phonon modes. The morphology of the film improved with the increase in deposition time. MIS capacitors were fabricated on n type silicon substrates, and the dependence of dielectric parameters with deposition time was investigated. Dielectric constants of 6.0-6.8 were obtained at 1 MHz. Response of AlN/Si films of different thicknesses, with Al and Pd catalytic over layers, was investigated for 50 ppm hydrogen. Pd/AlN/Si device fabricated with 114 nm layer of AlN revealed an enhanced response in the C-V characteristics, while Al/AlN/Si device did not show any effect, indicating that the hydrogen sensitivity is highly dependent on the gate outer surface and deposition time. © 2013 Elsevier B.V. All rights reserved.

Sakkaravarthi K.,Bishop Heber College | Kanna T.,Bishop Heber College
European Physical Journal: Special Topics | Year: 2013

In this paper, we construct the bright-soliton bound states of an integrable (2 + 1)-dimensional multicomponent long wave-short wave resonance interaction (LSRI) system by using the exact bright-soliton solutions obtained in Ref. [24] and analyze their interesting collision dynamics. We show that the beating and breathing oscillations of the bound solitons can be controlled by tuning the polarization parameters. Also, we explore the interaction between the bound-soliton and a standard soliton. We also point out that the two bound-soliton state seems to be robust against collision with a standard soliton and remain to be bounded even after collision. © 2013 EDP Sciences and Springer.

John Robinson P.,Bishop Heber College
International Journal of Fuzzy System Applications | Year: 2016

Solving Multiple Attribute Group Decision Making (MAGDM) problems has become one of the most important researches in recent days. In situations where the information or the data is of the form of an Intuitionistic Triangular Fuzzy Number (ITrFN) or Intuitionistic Trapezoidal Fuzzy Number (ITzFN), a new distance function is defined for ranking the alternatives in the decision making process. After processing the decision information through a sequence of arithmetic aggregation operators, namely, the Intuitionistic Triangular Fuzzy Weighted Arithmetic Averaging (ITrFWAA), Intuitionistic Triangular Fuzzy Ordered Weighted Averaging (ITrFOWA) operator and the Intuitionistic Triangular Fuzzy Hybrid Aggregation (ITrFHA) operator, the proposed distance function is utilized to rank the best alternative. A model is proposed to solve MAGDM problems using the developed distance formula defined for ITrFNs. Numerical illustration is provided and comparisons are made with some of the existing MAGDM models and ranking procedures. © 2016, IGI Global.

Vijayalakshmi K.,Bishop Heber College | David Jereil S.,Bishop Heber College
Ceramics International | Year: 2015

TiO2 and Fe-doped TiO2 nanowires were synthesized by spray pyrolysis technique to study their gas sensing properties towards ethanol. Charge transfer from metal dopant to TiO2, and modification of TiO2 with Fe doping was investigated for their ability to enhance gas sensing activity. The X-ray diffraction results indicate that the Fe dopant was substitutionally incorporated by replacing Ti4+ cations. Fourier transform infrared spectral analysis confirmed the presence of brookite TiO2. The UV-visible spectra showed the increase in absorption with Fe doping when compared with undoped TiO2 film, and optical band gap decreased slightly with Fe doping. SEM images revealed the presence of one dimensional structure of straight nanowires for undoped TiO2 and curved nanowires for Fe doped TiO2 films. To understand the enhancement of sensing performance of TiO2 film with Fe doping, the gas sensing mechanism of the film towards Ethanol at room temperature was studied and discussed. © 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Sakkaravarthi K.,Bishop Heber College | Kanna T.,Bishop Heber College
Journal of Mathematical Physics | Year: 2013

The exact bright one- and two-soliton solutions of a particular type of coherently coupled nonlinear Schrödinger equations, with alternate signs of nonlinearities among the two components, are obtained using the non-standard Hirota's bilinearization method. We find that in contrary to the coherently coupled nonlinear Schrödinger equations with same signs of nonlinearities the present system supports only coherently coupled solitons arising due to an interplay between dispersion and the nonlinear effects, namely, self-phase modulation, cross-phase modulation, and four-wave mixing process, thereby depend on the phases of the two co-propagating fields. The other type of soliton, namely, incoherently coupled solitons which are insensitive to the phases of the co-propagating fields and arise in a similar kind of coherently coupled nonlinear Schrödinger equations but with same signs of nonlinearities are not at all possible in the present system. The present system can support regular solution for the choice of soliton parameters for which mixed coupled nonlinear Schrödinger equations admit only singular solution. Our analysis on the collision dynamics of the bright solitons reveals the important fact that in contrary to the other types of coupled nonlinear Schrödinger systems the bright solitons of the present system can undergo only elastic collision in spite of their multicomponent nature. We also show that regular two-soliton bound states can exist even for the choice for which the same system admits singular one-soliton solution. Another important effect identified regarding the bound solitons is that the breathing effects of these bound solitons can be controlled by tuning the additional soliton parameters resulting due to the multicomponent nature of the system which do not have any significant effects on bright one soliton propagation and also in soliton collision dynamics. © 2013 American Institute of Physics.

Vijayalakshmi K.,Bishop Heber College | Karthick K.,Bishop Heber College
Journal of Materials Science: Materials in Electronics | Year: 2013

In this paper, we report the synthesis of nano-structured Zinc Oxide (ZnO) and Magnesium doped Zinc Oxide (ZnO:Mg) using air stable and inexpensive chemicals, by microwave assisted processing. The as-synthesized ZnO and ZnO:Mg nanopowders were annealed at 800 C for 1 h. The samples were further characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and room temperature photoluminescence (PL) spectra. The crystallite size of ZnO decreased from 24 to 16 nm, and the intensity of most prominent vibration band of ZnO becomes weak when Mg dopant is added. SEM images of Mg doped ZnO showed clearly distinct hexagonal shaped nanoparticles with good crystalline quality and size contrast to ZnO. The PL result indicate that the ZnO exhibit strong and sharp UV emission peak at 380 nm. Our result showed that, by doping magnesium into ZnO, the UV emission peak shift towards the lower wavelength at ∼370 nm with increasing intensity, which may be attributed to the size confinement. From this study, the microwave processing method has been proved to be successful for preparing other metal oxide nanopowders with good crystal quality. © 2013 Springer Science+Business Media New York.

Vijayalakshmi K.,Bishop Heber College | Karthick K.,Bishop Heber College
Philosophical Magazine Letters | Year: 2012

Zinc oxide (ZnO) nanoparticles have been synthesized by a microwave heating method. The resulting powders were annealed at temperatures from 400°C to 800°C for 4h. The annealed powders were characterized in terms of their structural, morphological, and optical properties by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and room-temperature photoluminescence (PL) spectroscopy, respectively. The XRD patterns of the samples revealed the formation of phase-pure ZnO, apparently without any impurities. However, FT-IR spectra revealed the presence of carboxylate impurities, the signals of which disappear as the annealing temperatures are increased from 400°C to 800°C. SEM pictures showed increasing size ZnO nanoparticles with increase in annealing temperature. The powder annealed at 800°C is identified as hexagonal wurzite ZnO. The improved PL spectral performance of the ZnO powder correlates well with the improved crystalline quality of the nanoparticles, as revealed by the XRD and PL. Sharp ultraviolet (UV) band edge luminescence has been observed at 375nm, which is suitable for application in UV light emitting devices. The results also showed that the excitation wavelength dependence of the luminescence arises from quantum confinement effects. © 2012 Taylor & Francis.

Vijayalakshmi K.,Bishop Heber College | Karthick K.,Bishop Heber College | Gopalakrishna D.,Bishop Heber College
Ceramics International | Year: 2013

Nanostructured zinc oxide (ZnO) thin film sensors were prepared by spray pyrolysis, and their structural, optical, photoluminescence and morphological properties were investigated by X-ray diffractometer, UV-vis spectrometer, photoluminescence spectrometer, and scanning electron microscope (SEM), respectively. The post-annealing of ZnO film in air at 400 °C was found to be effective for the distribution of grains and their sizes, which favors the c-axis orientation of the film. This enhancement is accompanied by an increase in the optical band gap from 3.4 eV to 3.53 eV, which confirms the uniformity of ZnO film prepared by using a specially designed spray nozzle. SEM micrograph after heat treatment revealed uniform distribution of particles with well grown grains of ZnO. Hydrogen sensing measurement indicated the annealed ZnO film to show much higher response than the as deposited film. To understand the enhancement of the sensing performance of the annealed ZnO film, the gas sensing mechanism of the film was proposed and discussed. The magnitudes of the sensor response as well as its dependence on annealing differ significantly depending on the crystallite size of the film. © 2012 Elsevier Ltd and Techna Group S.r.l.

Kanna T.,Bishop Heber College | Sakkaravarthi K.,Bishop Heber College
Journal of Physics A: Mathematical and Theoretical | Year: 2011

We consider the integrable multicomponent coherently coupled nonlinear Schrödinger (CCNLS) equations describing simultaneous propagation of multiple fields in Kerr-type nonlinear media. The correct bilinear equations of m-CCNLS equations are obtained using a non-standard type of Hirota's bilinearization method, and the more general bright one solitons with single-hump and double-hump profiles including special flat-top profiles are obtained. The solitons are classified as coherently coupled solitons and incoherently coupled solitons depending upon the presence and absence of coherent nonlinearity arising due to the existence of the co-propagating modes/components. Further, the more general two-soliton solutions are obtained using this non-standard bilinearization approach, and various fascinating collision dynamics are pointed out. Particularly, we demonstrate that the collision between coherently coupled solitons and incoherently coupled solitons displays a non-trivial behaviour in which the former always undergoes energy switching accompanied by an amplitude-dependent phase-shift and change in the relative separation distance, leaving the latter unaltered. But the collision between coherently coupled solitons alone is found to be a standard elastic collision. Our study also reveals the important fact that the collision between incoherently coupled solitons arising in the m-CCNLS system with m = 2 is always elastic, whereas for m > 2 the collision becomes intricate, and for this case the m-CCNLS system exhibits interesting energy-sharing collision of solitons characterized by intensity redistribution, amplitude-dependent phase-shift and change in relative separation distance, which is similar to that of the multicomponent Manakov soliton collisions. This suggests that the m-CCNLS system can also be a suitable candidate for soliton collision-based optical computing in addition to the Manakov system. © 2011 IOP Publishing Ltd.

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