Raj A.M.E.,Scott Christian College Autonomous |
Jayachandran M.,CSIR - Central Electrochemical Research Institute |
Sanjeeviraja C.,Alagappa University
CIRP Journal of Manufacturing Science and Technology | Year: 2010
During the past few decades, considerable research effort has been directed towards the development of fundamental peculiarities of wide-gap (E g > 5 eV) inorganic dielectric thin films. Wide-gap dielectrics are used for various technical and technological applications as laser materials, electronic components, radiation resistant materials, spectral transformers for luminescent lamps, detectors and dosimeters of several kind of radiations, various sensors and catalytic agents. The optical characteristics of intrinsic electronic excitations in inorganic wide-gap dielectric are shifted towards the vacuum ultra-violet spectral region and therefore being studied insufficiently that impedes the elaboration of new materials and the modernization of the existing ones based on wide-gap dielectrics. Besides, alkali halides, the value of energy band gap E g >6 eV is typical of numerous wide-gap oxides: MgO, CaO, Al 2O 3, SiO 2, Y 2O 3, etc. Among this, magnesia (MgO) is a well-known refractory oxide, has the potential advantages of a wide band gap (E g ∼ 7.8 eV) and is predominantly preferred to be used as lattice templates for growing oriented ferroelectric and superconducting over layers because of its higher Poisson's ratio and lower Gibb's free energy. Well-defined procedures to prepare MgO surfaces of very high quality is of importance in a number of areas of surface physics and imperfect due to their preparation kinetics, inclusion of foreign matter and compositional variations. Even though, increasing number of researchers, laboratories have engaged in the fabrication and characterization of MgO because of its excellent scientifically based applications. The scope of this review article is to summarize briefly the important research achievements on higher quality MgO thin films with novel physical properties and systematic interrelationship for fabrication conditions, crystal structure, composition predictions, surface morphology, electrical and optical characterizations. Particular attention is given to the secondary electron emission coefficient of the fabricated film due to their applications in the alternating current plasma display panel as a protecting layer of dielectrics to improve the discharge characteristics and the panel's lifetime. © 2010 CIRP.
Khan M.F.,Sadakathullah Appa College Autonomous |
Godwin Wesley S.,Scott Christian College Autonomous
Marine Pollution Bulletin | Year: 2011
The activities of 210Po and 210Pb were determined in commonly consumed seafoods to evaluate the internal exposure and risk to humans residing Kudankulam coast where a mega nuclear power plant is under construction. The concentration of 210Po in seafoods ranged from 1.2±0.7 to 248±8.1Bqkg-1. Meanwhile, 210Pb ranged between 1.1±0.05 and 14.8±1.6Bqkg-1. The committed effective dose (CED) due to 210Po and 210Pb varied from 11.04 to 515.6 and 3.93 to 23.5μSvyr-1, respectively. The lifetime cancer risk for the public due to 210Po was in the range of 3.47×10-5-1.62×10-3 and it was 4.03×10-5-1.96×10-4 due to 210Pb. The activity intake, effective dose and cancer risk was found lesser than international guidelines and the seafood intake was considered to be safe for human consumption. © 2010 Elsevier Ltd.
Besky Job C.,Scott Christian College Autonomous
International Journal of ChemTech Research | Year: 2015
Sodium Penta Borate Na(H4B5O10) crystal has been grown by slow evaporation technique using deionized water as solvent. The grown crystal was confirmed by powder and single crystal X-ray diffraction studies. FTIR spectrum reveals the presence of functional groups present in the grown crystal. UV-Vis spectral studies performed the cut off wavelength of the grown crystal as 202 nm in the UV region. The thermal properties of the grown crystal were studied by TGA-DTA and the melting point has been found out as 198°C. The dielectric behaviour of the grown crystal has been investigated with different frequencies at different temperatures. © 2015, Sphinx Knowledge House. All rights reserved.
Feroz Khan M.,Sadakathullah Appa College Autonomous |
Godwin Wesley S.,Scott Christian College Autonomous
Marine Pollution Bulletin | Year: 2012
Protection of non-human biota from ionizing contaminants, especially in the vicinity of nuclear installations is a very important aspect for nuclear engineers and ecologists. In this view, a baseline data on the activity concentration of 210Po and 210Pb were quantified in different tissues of molluscs inhabiting the intertidal region along the coast of Kudankulam. The activity concentration was noticed higher in the organs associated with digestion and metabolism. Filter feeding bivalve molluscs registered the maximum activity of 210Po in their whole body compared to grazing gastropods. 210Po: 210Pb ratio was calculated to be greater than unity in most of the analysed tissues. The ecological sensitivity of molluscs to the radiation exposure and the safeness of the environment was analysed by calculating the external and internal dose rate. The hazard quotient for molluscs was lesser than the global bench mark dose rate of 10μGyh -1. © 2011 Elsevier Ltd.
Godwin Wesley S.,Scott Christian College Autonomous |
Rajan M.P.,Bhabha Atomic Research Center
Journal of Environmental Radioactivity | Year: 2014
The present study focused on the determination of the alpha-emitter, 210Po, in two species of marine mussels (bivalve molluscs) commonly available in the southern coastal region of India. The brown mussel, Perna indica was collected from the west coast and the green mussel, Perna viridis from the east coast. The concentration of 210Po was related to the allometry (length of shell, wet/dry weight of shell/soft tissue) of the mussels and significant results were found. The study period focused on three seasons namely, pre-monsoon, monsoon and post-monsoon for a 1-year period (2010-2011). The results revealed higher activity levels in smaller-sized mussels compared to larger ones. Marked variation in 210Po activity concentration was noted in the whole-body soft tissues between seasons and sampling site (p<0.05). The dose rate assessment for mussels was performed using the ERICA Assessment tool. The chronic exposure to mussels due to 210Po was found to be lesser than the global benchmark dose rate of 10μGyh-1. The effective ingestion dose to adults who intake mussels was estimated to be in the range 5.1-34.9μSvy-1. The measurement contributes to the furthering of knowledge of 210Po, since no data exist in this region. © 2014 Elsevier Ltd.