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Search Results: 1 - 10 of 623 matches for " Krishnamoorthy Karthikeyan "
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Synthesis and properties of ZnO nanorods by modified Pechini process
Ramasamy Devaraj,Krishnamoorthy Karthikeyan,Kadarkaraithangam Jeyasubramanian
Applied Nanoscience , 2013, DOI: 10.1007/s13204-012-0072-1
Abstract: Zinc oxide (ZnO) nanorods have been successfully synthesized by modified Pechini process. The as-synthesized ZnO nanorods were characterized by X-ray diffraction, scanning electron microscope, Raman spectrum, ultraviolet–visible (UV–vis) spectrum. X-ray diffraction result shows that the ZnO nanorods are oriented in wurtzite phase. Raman spectroscopy measurements revealed the presence of E2 (high) mode at 437 cm 1 indicating the high crystallinity of the as-synthesized ZnO nanorods. The optical property of the ZnO nanorods were studied from their UV–vis spectroscopy analysis which exhibits the absorbance at 373 nm corresponds to the Zn–O absorption. A mechanism for modified Pechini process for the synthesis of ZnO nanorods using citric acid–ethylene glycol precursor has also been proposed.
Graphene oxide nanostructures modified multifunctional cotton fabrics
Karthikeyan Krishnamoorthy,Umasuthan Navaneethaiyer,Rajneesh Mohan,Jehee Lee,Sang-Jae Kim
Applied Nanoscience , 2012, DOI: 10.1007/s13204-011-0045-9
Abstract: Surface modification of cotton fabrics using graphene oxide (GO) nanostructures was reported. Scanning electron microscopic (SEM) investigations revealed that the GO nanostructure was coated onto the cotton fabric. The molecular level interaction between the graphene oxide and the cotton fabric is studied in detail using the Fourier transform infra-red (FTIR) spectra. Thermogravimetric analysis (TGA) showed that GO loaded cotton fabrics have enhanced thermal stability compared to the bare cotton fabrics. The photocatalytic activity of the GO-coated cotton fabrics was investigated by measuring the photoreduction of resazurin (RZ) into resorufin (RF) under UV light irradiation. The antibacterial activity was evaluated against both Gram-negative and Gram-positive bacteria and the results indicated that the GO-coated cotton fabrics are more toxic towards the Gram-positive ones. Our results provide a way to develop graphene oxide-based devices for the biomedical applications for improving health care.
Detection of Epileptic Seizure in EEG Recordings by Spectral Method and Statistical Analysis
D.K. Ravish,S. Shenbaga Devi,S.G. Krishnamoorthy,M.R. Karthikeyan
Journal of Applied Sciences , 2013,
Abstract: Electroencephalographs are records of brain electrical activity. It is an indispensable tool for diagnosing epileptic seizure. Manually reviewing EEG recordings for detection of epilepsy pattern is a time-consuming process. It is, therefore, necessary to automate the epileptic seizure detection. Further analyzing after the detection using large data set is a good supplement to the wide range of algorithms currently used for analysis. Seizure evolution is typically a dynamic and non stationary process and the EEG signals are composed of many frequency bands. The objective of this work was to determine features that differentiated epileptic seizure from a normal activity. Subjects suffering from a commonly occurring generalized epileptic seizure EEG segments and non seizure EEG segments are used for the study. The Spectral and Statistical methods are applied to the signal and the features are extracted. Spectral power, Standard deviation, Variance, Root Mean Square and Measure of Spread are the features that differentiate abnormal activity from normal activity whereas Median, Mode, Skewness, kurtosis are not able to differentiate. This study gives a method to detection of seizure and analysis in offline. It can be further extended to the real time. The algorithm is tested with two different databases covering children and as well as adult data sets.
Routing Strategy Selection for Zigbee Mesh Networks  [PDF]
Ramanathan Karthikeyan
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2010.37081
Abstract: Based on IEEE 802.15.4 Low Rate-Wireless Personal Area Network (LR-WPAN) standard, the Zigbee standard has been proposed to interconnect simple, low rate and battery powered wireless devices. The deployment of Zigbee network is expected to facilitate numerous applications such as Home-appliance networks, home healthcare, medical monitoring and environmental sensors. An effective routing scheme is more important for Zigbee mesh networks. In order to achieve effective routing in Zigbee Mesh networks, a Zigbee protocol module is realized using NS-2. The suitable routing for different data services in the Zigbee application layer and a best routing strategy for Zigbee mesh network are proposed. The simulation shows the selection of suitable routing for continuous data services and for bursting data services in the Zigbee application layer and the comparison of three routing strategies namely ERD (All packets Enable Route Discovery), SRD (All packets Suppress Route Discovery) and BOS (routing Based on Data Services) in the aspects of Efficiency and Overhead.
Comparison and Performance Analysis of FACTs Controller in System Stability  [PDF]
Karthikeyan Ramasamy
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.710253
Abstract: In large inter connected power systems, inter-area oscillations are turned to be a severe problem. Hence inter-area oscillations cause severe problems like damage to generators, reduce the power transfer capability of transmission lines, increase wear and tear on network components, increase line losses etc. This paper is to maintain the stability of system by damping inter-area oscillations. Implementation of new equipment consists of high power electronics based technologies such as FACTs and proper controller design has become an essential to provide better damping performance than Power System Stabilizer (PSS). With development of Wide Area Measurement System (WAMS), remote signals have become as feedback signals to design Wide Area Damping Controller (WADC) for FACTs devices. In this work, POD is applied to both SVC and SSSC. Simulation studies are carried out in Power System Analysis Toolbox (PSAT) environment to evaluate the effectiveness of the FACTs controller in a large area power system. Results show that extensive analysis of FACTs controller for improving stability of system.
A New Clock Gated Flip Flop for Pipelining Architecture  [PDF]
Krishnamoorthy Raja, Siddhan Saravanan
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.78119
Abstract: The objective of the work is to design a new clock gated based flip flop for pipelining architecture. In computing and consumer products, the major dynamic power is consumed in the system’s clock signal, typically about 30% to 70% of the total dynamic (switching) power consumption. Several techniques to reduce the dynamic power have been developed, of which clock gating is predominant. In this work, a new methodology is applied for gating the Flip flop by which the power will be reduced. The clock gating is employed to the pipelining stage flip flop which is active only during valid data are arrived. The methodology used in project named Selective Look-Ahead Clock Gating computes the clock enabling signals of each FF one cycle ahead of time, based on the present cycle data of those FFs on which it depends. Similarly to data-driven gating, it is capable of stopping the majority of redundant clock pulses. In this work, the circuit implementation of the various blocks of data driven clock gating is done and the results are observed. The proposed work is used for pipelining stage in microprocessor and DSP architectures. The proposed method is simulated using the quartus for cyclone 3 kit.
Hybrid Voltage Control Model for Hybrid Renewable Energy System Using Artificial Bees Colony Algorithm  [PDF]
Mahendran Krishnamoorthy, Prabha Umapathy
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.79238
Abstract: This paper proposed a hybrid control model-based voltage control of Hybrid Energy System (HES) that includes both solar and wind energy conversion systems. The proposed hybrid voltage control model is the combination process of both the Artificial Bees Colony algorithm (ABC) and Proportional Integral controller (PI). The novelty of the proposed method is intelligent foraging behavior of honey bee swarm, which provides random reduction and ability to adapt complex optimization problems. Here, the ABC optimizes the gain parameters under various operating conditions using the minimized Square Error (SE). It considers the actual voltage outcome of the buck converter and the set point voltage. By using the optimized gain parameters, the PI controller is operated. Each separate energy conversion system is controlled by the separate proposed hybrid voltage control model. The proposed method is implemented in MATLAB/Simulink platform and the performance is verified using the comparative analysis with the existing techniques. The comparison results prove the superiority of the proposed method.
Tire Pressure Monitoring System Using SoC and Low Power Design  [PDF]
A. Vasanthara, K. Krishnamoorthy
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.713337
Abstract:

This paper presents the tire pressure monitoring system (TPMS) by using the system on chip (SoC) mixed signals with the help of Bluetooth transmission and in advantage of low power consumption design. This is to monitor the variations in temperature and pressure of the vehicle’s tire, and the TPMS system is involved. It improves the driver’s safety by automatically detecting the tire pressure and temperature and then warning signal is sent to driver to take a measure, which prevents from accident. The proposed system of tire pressure monitoring system using SoC increases the speed of indication time to the driver by using mixed signals. The inflation of the tire can be avoided by preventing from high temperature and high pressure. Limitation of temperature and pressure in the previous system is also elongated i.e. temperature from 40to 125 and pressure from 0 to 750 Kpa. Sensors, wireless communication (Bluetooth dongle) and SoC unit are used to design the low power TPMS. Quantitative results are taken and the analogy between temperature and pressure is also verified. The tested results proved by need of the practical system. Signal conditioning voltage and SoC unit is the trace for low power design TPMS. Finally, the performance of the system is tested and executed by using proteus software given as a real time application.

Cardioprotective effect of the Hibiscus rosa sinensis flowers in an oxidative stress model of myocardial ischemic reperfusion injury in rat
Karunakaran K Gauthaman, Mohamed TS Saleem, Peter T Thanislas, Vinoth V Prabhu, Karthikeyan K Krishnamoorthy, Niranjali S Devaraj, Jayaprakash S Somasundaram
BMC Complementary and Alternative Medicine , 2006, DOI: 10.1186/1472-6882-6-32
Abstract: The medicinal values of the flowers of Hibiscus rosa sinensis (Chinese rose) have been mentioned in ancient literature as useful in disorders of the heart. Dried pulverized flower of Hibiscus rosa sinensis was administered orally to Wistar albino rats (150–200 gms) in three different doses [125, 250 and 500 mg/kg in 2% carboxy methyl cellulose (CMC)], 6 days per week for 4 weeks. Thereafter, rats were sacrificed; either for the determination of baseline changes in cardiac endogenous antioxidants [superoxide dismutase, reduced glutathione and catalase] or the hearts were subjected to isoproterenol induced myocardial necrosis.There was significant increase in the baseline contents of thiobarbituric acid reactive substances (TBARS) [a measure of lipid per oxidation] with both doses of Hibiscus Rosa sinensis. In the 250 mg/kg treated group, there was significant increase in superoxide dismutase, reduced glutathione, and catalase levels but not in the 125 and 500 mg/kg treated groups. Significant rise in myocardial thiobarbituric acid reactive substances and loss of superoxide dismutase, catalase and reduced glutathione (suggestive of increased oxidative stress) occurred in the vehicle treated hearts subjected to in vivo myocardial ischemic reperfusion injury.It may be concluded that flower of Hibiscus rosa sinensis (250 mg/kg) augments endogenous antioxidant compounds of rat heart and also prevents the myocardium from isoproterenol induced myocardial injury.Reperfusion of the ischemic myocardium is the only logical approach for the successful management of patients with IHD. Morphological observations of the ischemic myocardial tissue undergoing reperfusion suggest that it is a true pathological phenomenon and a distinct entity from the preceding ischemic injury [1,2]. Reperfusion of ischemic myocardium is accompanied by the development of oxidative stress and the generation of free radicals which plays a major role in the etiopathogenesis of reperfusion injury [3]. The
A validated, related substance, GC method for 1,4-cyclohexanedione mono-ethylene Ketal  [PDF]
B. Karthikeyan, V. Srinivasan
Journal of Biophysical Chemistry (JBPC) , 2010, DOI: 10.4236/jbpc.2010.11009
Abstract: ABSTRACT A simple, economic, and time-efficient related substance, GC method has been developed for the analysis of 1,4-Cyclohexanedione mono- ethylene ketal(will be specified as ketal) in the presence of a potential impurity 1,4-cyclohexa- nedione bis (ethylene ketal) [will be specified as diketal]. Successful chromatographic separa- tion of the ketal from the impurity was achieved on a DBWAX ETR, 30 m x 0.32 mm x 1.0μ FT column with nitrogen as carrier gas and FID detector. The method was validated for linearity, accuracy, precision, and specificity and can be used for quality control during manufacture of ketal. A validated GC method is reported for the ketal for the first time.
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