The Shanmugha Arts, Science, Technology & Research Academy, known as SASTRA University, is a deemed university in the town of Thirumalaisamudram, Thanjavur district, Tamil Nadu, India. Undergraduate and postgraduate engineering courses are its focus Wikipedia.
Chandiramouli R.,SASTRA University
Ceramics International | Year: 2014
The electronic transport properties of cadmium sulfide nanoribbon based molecular device were investigated by employing first principles calculation using density functional theory. The electronic properties are discussed in terms of density of states spectrum and electron density. The density of states of charge depends on the applied bias voltage. The electron density is seen more at cadmium sites. The transport properties of CdS nanoribbon are studied using transmission coefficient spectrum and transmission pathways. The electronic transmission all along the scattering region depends on the bias voltage; depending upon the bias voltage the transmission path also gets altered. The information provided in the present study will pave way to tailor nanostructures with improved performance in nanoelectronic devices. © 2014 Elsevier Ltd and Techna Group S.r.l.
Mani G.K.,SASTRA University |
Rayappan J.B.B.,SASTRA University
Sensors and Actuators, B: Chemical | Year: 2013
Nanostructured ZnO thin films were deposited on glass substrates at 503 K using spray pyrolysis technique and the films were post annealed at 673 K in air atmosphere for 3 h. The structural, morphological and optical properties of as-deposited and annealed samples were investigated. The annealed films showed uniform spherical morphology in contrast with as-deposited films. XRD patterns of both the annealed and as-deposited films confirmed the polycrystalline nature of the films with hexagonal wurtzite structure. Room temperature ammonia sensing characteristics of annealed films were studied for various concentration levels of ammonia at dry air and humidity conditions. A highest room temperature response of 233 was achieved at 25 ppm of NH3 with a response and recovery times of 20 and 25 s respectively. The response of the sensor to other gases such as methanol, ethanol, 2-propanol, benzyl alcohol and acetone indicated a high selectivity towards ammonia gas. The room temperature (303 K) operation, with high selectivity, repeatability and fast transition times of the sensor together with the low deposition cost suggests suitability for developing a low power cost-effective ammonia sensor. © 2013 Elsevier B.V.
Anthony S.P.,SASTRA University
ChemPlusChem | Year: 2012
Organic fluorescent materials have been an integral part of recently emerged optoelectronic device technologies owing to their good photophysical properties such as high quantum yields and significant photostability In particular, switchable and tunable solid-state fluorescence has attracted increasing attention in recent years both in the field of fundamental research and industrial applications. Unlike in solution, fluorescence in the solid state is a collective phenomenon of molecules that are commonly modulated through controlling molecular packing and the electronic conjugation of fluorophores. Several strategies, including chemical modification, have been developed to alter the fluorophore molecular arrangement in the solid state. This Review article describes the various strategies that have been effectively utilised to achieve switchable and tunable fluorescence in the organic solid state. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Chandiramouli R.,SASTRA University
Superlattices and Microstructures | Year: 2015
The band structure and electronic transport property of InP nanotube molecular device are studied using density functional theory with GGA/PBE exchange correlation functional. The substitution of nitrogen in InP nanotube slightly widens the band gap. The substitution of nitrogen and aluminium in InP nanostructure modifies the density of states across InP nanotube. The electron density is found to be more on phosphorus sites than indium sites. The substitution of aluminium increases the electron density, whereas nitrogen substitution decreases the electron density across phosphorus site. The transmission spectrum provides the insight to transmission along InP nanotube molecular device. The transmission pathways get modified with the substitution impurity along InP nanotube molecular device. The results of the present work will give information on tuning the band structure and transport properties of InP nanotube molecular device. © 2015 Elsevier Ltd. All rights reserved.
Chandiramouli R.,SASTRA University
Research Journal of Chemistry and Environment | Year: 2013
The realistic clusters of BaS were completely optimized using B3LYP/LanL2DZ basis set. The possible structures such as linear, ring and three dimensional structures were optimized for the structural stability using calculated energy and binding energy. The dipole moment and point symmetry were also studied for different structures. The electronic properties were studied with the help of HOMO-LUMO gap, ionization potential and electron affinity. The information reported for various structures of BaS will give an insight tosynthesizea proper structure which will find its potential importance in engineering applications.
Suribabu C.R.,SASTRA University
Journal of Hydroinformatics | Year: 2010
Water distribution networks are considered as the most important entity in the urban infrastructure system and need huge investment for construction. The inherent problem associated with cost optimisation in the design of water distribution networks is due to the nonlinear relationship between flow and head loss and availability of the discrete nature of pipe sizes. In the last few decades, many researchers focused on several stochastic methods of optimisation algorithms. The present paper is focused on the Differential Evolution algorithm (henceforth referred to as DE) and utilises a similar concept as the genetic algorithm to achieve a goal of optimisation of the specified objective function. A simulation-optimisation model is developed in which the optimization is done by DE. Four well-known benchmark networks were taken for application of the DE algorithm to optimise pipe size and rehabilitation of the water distribution network. The findings of the present study reveal that DE is a good alternative to the genetic algorithm and other heuristic approaches for optimal sizing of water distribution pipes. © IWA publishing 2010.
Hariharan G.,SASTRA University
Journal of Mathematical Chemistry | Year: 2013
In this paper, the Homotopy analysis method (HAM) is employed to obtain the analytical/numerical solutions for linear and nonlinear Kolmogorov Petrovskii-Piskunov (KPP) and fractional KPP equations. The proposed method is a powerful and easy-to-use analytical tool for linear and nonlinear problems. This method contains the auxiliary parameter h, which provides us with a simple way to adjust and control the convergence region of solution series. Some illustrative examples are presented. Moreover the use of HAM is found to be accurate, simple, convenient, flexible and computationally attractive. © 2012 Springer Science+Business Media New York.
Nagarajan S.,SASTRA University
Applied Biochemistry and Biotechnology | Year: 2012
Fat-splitting enzymes (lipases), due to their natural, industrial, and medical relevance, attract enough attention as fats do in our lives. Starting from the paper that we write, cheese and oil that we consume, detergent that we use to remove oil stains, biodiesel that we use as transportation fuel, to the enantiopure drugs that we use in therapeutics, all these applications are facilitated directly or indirectly by lipases. Due to their uniqueness, versatility, and dexterity, decades of research work have been carried out on microbial lipases. The hunt for novel lipases and strategies to improve them continues unabated as evidenced by new families of microbial lipases that are still being discovered mostly by metagenomic approaches. A separate database for true lipases termed LIPABASE has been created recently which provides taxonomic, structural, biochemical information about true lipases from various species. The present review attempts to summarize new approaches that are employed in various aspects of microbial lipase research, viz., screening, isolation, production, purification, improvement by protein engineering, and surface display. Finally, novel applications facilitated by microbial lipases are also presented. © Springer Science+Business Media, LLC 2012.
Thiruvasagam P.,SASTRA University
Designed Monomers and Polymers | Year: 2013
Thermally stable/high-performance polymers are able to provide long-term service at elevated temperatures. The development of different thermally stable polymers is continued due to the large requirement of high-temperature polymers. Polyimides (PI) and their copolyimides are well-established class of high-performance polymers that show good combination of thermal, mechanical, and electrical properties. These stable PI are widely used in electrical, electronics, automotive, and aerospace industries. This article reviews the synthesis and characterization of AB-type monomers, AB-type PI, and copolyimides having different structures. AB-type PI are synthesized by self-condensation of AB-type monomers. The requirement of stoichiometric equivalence to obtain high-molecular-weight polyimide will be easily met by using AB-type monomers. This discussion covers different structures of AB-type monomers based PI and their properties. The variations in the structure of the monomers have effect on the properties of the final PI. The structure-property relationships also have been discussed. Copyright © 2012 Taylor & Francis.
Amirtharajan R.,SASTRA University |
Balaguru Rayappan J.B.,SASTRA University
Information Sciences | Year: 2012
Steganography's role in secret communication extends from concealing information to communication. As one of several possible approaches to embed confidential information in digital images, the Least Significant Bit (LSB) technique has been widely used; however, maintaining the imperceptibility of the stego-image is still a serious concern. In this paper, an Adaptive Random (AR) k-bit embedding approach has been attempted to enhance the quality of stego-images. The original cover is divided into nonoverlapping blocks of equal size. The encrypted confidential data are embedded in each block through four different random walks. The best random walk, which provides the minimum degradation for a particular block, is identified, and is fixed for that block. The decision on the fixed random walk for each block is recorded and kept as the secret key. The AR method has also been combined with the Inverted Pattern approach, referred to as the Adaptive Random Inverted Pattern (ARIP) approach, to further enhance the quality of the stego-image. The estimated Peak Signal to Noise Ratio (PSNR) value for the ARIP method yields 1 dB enhancement. © 2011 Elsevier Inc. All rights reserved.