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Vijayakumar, V.
- A Study on Variation in Ionic Composition of Aqueous System in Different Lithounits around Perambalur Region, Tamil Nadu
Authors
1 Department of Earth Sciences, Annamalai University, Annamalai Nagar - 608 002, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 70, No 6 (2007), Pagination: 1061-1069Abstract
Hydrogeochemistry of a region is a reflection of the hydrodynamic processes, Lithological composition and physical constraints. Case study has been carried out in a varied lithologica] terrain with Archaean, Gondwana and Cretaceous rocks to unravel the hydrogeochemical process. The study area is around Perambalur region lying between Latitudes 11°O8OO" - ll°31OO" and Longitudes 78°35'00" - 78°5950" Pco2 values of water samples show wide variation in lithology, reflecting higher saturation index in carbonate minerals Mixing of water was witnessed in the Cretaceous formation Release of bicarbonate ions into the system is mainly derived from weathering of carbonate minerals reflecting lesser significance of silicate weathering. Thermodynamic equilibrium plot shows grouping of samples in the Kaolinite field with seasonal variation Saturation index (SI) for carbonate minerals is higher than silicate minerals Dilutions of samples are noted in the Archaean formation during Post-Monsoon season and migration of SI plume of carbonate minerals is towards southeast during Post-Monsoon season Geochemical reactions determining the water chemistry of the study area are also obtained by statistical analysis.Keywords
Hydrogeochemistry, Lithological Differentiation, Saturation Index, Perambalur Area, Tamil Nadu.- Enhanced Optical Effect on the Characteristics of MODFET under Back Side Illumination
Authors
1 Sathyabama University, Chennai-600118, Tamilnadu, IN
2 St.Josephs Engineering College, Chennai-600118, Tamilnadu, IN
Source
Programmable Device Circuits and Systems, Vol 3, No 7 (2011), Pagination: 348-353Abstract
The DC performance of depletion mode AlGaAs/GaAs MODFET under backside optical illumination is studied. A device structure with fiber inserted into the substrate upto the GaAs layer is considered for direct illumination into the GaAs layer. The AlGaAs layer is considered transparent to illumination. The photoconductive effect and the internal reflection effect which increase the 2DEG channel electron concentration are considered. These free electrons generated in the GaAs layer due to both photoconductive effect and the internal reflection effect are collected in 2DEG, there by increasing the source to drain current. The photo generated holes in GaAs layer drift towards the semi-insulating substrate and are capacitively coupled into the grounded source. The sheet concentration , I-V characteristics, transconductance and transfer characteristics of the device AlGaAs/GaAs MODFET have been evaluated and discussed. The I-V characteristics is compared with available experimental data at a particular gate source voltage with and without illumination.
Keywords
Optical Illumination, MODFET, Sheet Concentration, Transconductance, 2DEG.- A Comparative Study of CSA Design Using CNTFET and MOSFET
Authors
1 Sathyabama University, Chennai, Tamilnadu, IN
Source
Automation and Autonomous Systems, Vol 4, No 6 (2012), Pagination: 248-252Abstract
This paper enumerates the design and analysis of a Carry Select Adder (CSA) using Full Adder cell. The Full Adder is designed using MOSFET 32nm model, Stanford University CNTFET model and proposed 10nm CNTFET model. There are many issues facing while integrating more number of transistors like short channel effect, power dissipation, scaling of the transistors. Inorder to overcome these problems and still reduce transistor size, Carbon Nano Tube Field Effect Transistors or CNTFETs have promising applications in the field of electronics. The carbon nanotube is emerging as a viable replacement to the MOSFET. The transient and power analyses in this paper are obtained with operating voltage at 0.9V. The simulation results are presented and the analyses are compared with circuits designed using 32nm MOSFET. The comparison of results indicated that the proposed 10nm CNTFET based design is more efficient in power savings and speed.Keywords
CNT, CNTFET, Full Adder Cell, Carry Select Adder, Design Constraints, Circuit Simulation, CSA, 32nm, 10nm, Ballistic CNTFET Model, HSPICE, TSPICE.- Basic Volcanism along K-T Boundary from Rajahmundry, East Coast of India
Authors
1 Department of Geology, Andhra University, Visakhapatnam - 530 003, IN