515 research outputs found

    Morpho-anatomical responses of Catharanthus roseus due to combined heavy metal stress observed under Scanning Electron Microscope

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    Heavy metals trigger various plant responses that basically vary with the intensity as well as duration of stress. Comprehension of the morphological and anatomical responses to such stress is essential for a holistic perception of plant resistance mechanisms to metal-excess conditions in higher plants. In the present study, the effects of heavy metals on morpho-anatomy of Catharanthus roseus based on its potential to tolerate metal stress has been studied in industrially polluted environments. The tissue samples of these plants grown in contaminated and uncontaminated soils were processed for analysis under Scanning Electron Microscope (SEM). Briefly, harvested tissues were pre-fixed using glutaraldehyde and paraformaldehyde in sodium cacodylate (CAC) buffer, followed by post fixation in osmium tetroxide. Further, the digital micrographs of critically dried samples were captured. The analysis of micrographs revealed structural changes like cell wall thickening, increased stele diameter, increased root and shoot diameter, variations in stomatal number, enlargement of trichomes and salt glands of plants grown in contaminated soil when compared to those grown in uncontaminated soil. The study also provided microscopic evidence of endophytic colonization of microorganisms within surface-disinfected plant tissues. Based on the varied morpho-anatomical responses due to heavy metal stress, several physiological and metabolic mechanisms of plants were deciphered

    Delay Comparison for 16x16 Vedic Multiplier Using RCA and CLA

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    In any integrated chip compulsory adders are required because first they are fast and second are the less power consumption and delay. And at the same time multiplication process is also used in various applications. So as the speed of multiplier increases then the speed of processor also increases. And hence we are proposing the Vedic multiplier using these adders. Vedic multiplier is an ancient mathematics which uses mainly 16 sutras for its operation. In this project we are using “urdhva triyagbhyam” sutra to do our process. This paper proposes the Vedic multiplier using the adders ripple carry adder(RCA) and carry look ahead adder(CLA) and puts forward that CLA is better than RCA.The major parameters we are simulating here are number of slices and delay. The code is written by using Verilog and is implemented using Xilinx ISE Design Suite

    Use of Plasma Pseudocholinesterase as a Predictor of Mortality in Organophosphate Poisoning

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    The study was conducted on patients of organophosphate poisoning admitted to Bapuji Hospital (J. J. M. Medical College), Davangere during a period of October 2011 to March 2013. To know the incidence of acute Organophosphate poisoning, epidemiological aspects of the patient and plasma pseudocholinesterase levels at the time of admission and correlation within hospital mortality. Total number of cases studied were 150. At the time of admission blood was drawn for estimation of plasma pseudocholinesterase estimation. The patients were clinically divided into three grades according to Dreishbachs criteria. Analysis was performed by cobas integra 400 cholinesterase assay system. All patients were followed-up for 3 days to know the outcome. Majority of the cases (40%) belong to 21 to 30 years age group and predominantly belonged to male sex (73%). Seventy eight cases (52%) had severe poisoning, 40 cases (26.67%) had moderate poisoning and 32 cases (21.33%) had mild poisoning. Sixty cases (40%) had fatal outcome. Suicidal consumption was seen in 128 cases (85.33%). Plasma pseudocholinesterase levels associated with fatalities in severe poisoning and was found to range from 912 to 2490 U/L which accounts to suppression of plasma pseudocholinesterase levels by 84.04 to 93.19%

    Comparative Analysis of QoS-Aware Routing Protocols for Wireless Sensor Networks

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    The main ability of wireless sensor networks (WSNs) is communicating and sensing between nodes, which are deployed in a wide area with a large number of nodes. Wireless sensor networks are composed of a large number of sensor nodes with limited energy resources. One critical issue in wireless sensor networks is how to gather sensed information in an energy efficient way, since their energy is limited. The limiting factors of the sensor nodes, such as their finite energy supplies and their moderate processing abilities, as well as the unreliable wireless medium restrict the performance of wireless sensor networks While contemporary best-effort routing approaches address unconstrained traffic, QoS routing is usually performed through resource reservation in a connection-oriented communication in order to meet the QoS requirements for each individual connection. This article surveys a sample of existing QoS-Aware Routing Protocols for Wireless Sensor Networks and highlights their key features, including merits and limitations. Keywords: Wireless sensor networks, Routing protocols, QoS-Aware Routing Protocols

    Preemptive Routing & Intrusion Detection for MANETs

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    An ad-hoc network will often change rapidly in topology, this courses for routes in the network to often disappear and new to arise. The Ad-hoc On-Demand Distance Vector Routing Protocol(AODV), is based on the principle of discover routes as needed. In this paper we will extend the definition of AODV with the ability to discover multiple routes to a host and switch between them, if an active route is becoming weak and there is a risk that it will disappear. We will refer to it as pre-emptive AOMDV . We will show that the performance of pre-emptive AOMDV do handle changes in topology better than AODV it self. To show the effect of extending AODV, the suggested protocol is implemented in a simulator. Performance enhancements will be presented from different scenarios, to compare pre-emptive AOMDV with the ordinary AODV. In this paper we also focus on intrusion detection based on Finite State Machine and cache memory in ad hoc networks. Security is one of the most important issues in current networks. The most common cases of attacks in mobile Ad hoc networks can be drop of routing packets and changes in the incoming packets which aims at disrupting the network routing and overall network reduce performance. The presented approach based on FSM focuses at recognizing the malicious nodes within the network in a fast and accurate way, then it deals with rapid introduction of the malicious nodes to other nodes in the network to prevent sending multiple packets and drop and packet change. Finally, we will show the significant improvement in comparison with others, we simulated our methods by NS2 software

    Fault Tolerant Multilevel Inverter Topologies with Energy Balancing Capability: Photovoltaic Application

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    The continuous increase in energy demand and depletion of conventional resources motivates the research towards the environment friendly renewable energy sources like solar and wind energy. These sources are best suitable for rural, urban and offshore locations, because of easy installation, less running cost and ample resources (sun light and wind). The remote locations are mostly islanded in nature and far away from technical expertise in case of troubleshooting. This motivates the research on development of fault tolerant converters. These fault tolerant converters increases the reliability, which provides the continuous power supply to critical loads. From the last few decades, the integration of multilevel inverters with renewable energy systems is also increasing because of advantages like, improved power quality, total harmonic distortion (THD) and reduced output filter size requirement. Employing conventional multilevel inverters for increasing the number of voltage levels increases the device count and isolated DC sources. As a result probability of semiconductor switch failure is more and energy balancing issue between sources, which in-turn degrades the reliability and performance of the inverter. The majority of conventional multilevel inverter topologies cannot address energy balancing issues between multiple photovoltaic (PV) sources, which may need because of partial shading, hotspots, uneven charging and discharging of associated batteries etc. If energy sharing not addressed effectively, the batteries which are connected to the shaded or faulty PV system will discharge faster which may cause total system shutdown and leads to under-utilization of healthier part of the system. To address these issues, fault tolerant multilevel inverter topologies with energy balancing capability are presented in this thesis. The major contributions of the proposed work are Single phase and three phase fault tolerant multilevel inverter topologies. viii Energy balancing between sources and dc off set minimization (or batteries) due to uneven charging and discharging of batteries for five-level inverter. Extending the fault tolerance and energy balancing for higher number of voltage levels. The first work of this thesis is focused to develop fault tolerant single phase and three phase multilevel inverter topologies for grid independent photovoltaic systems. The topologies are formed by using three-level and two-level half bridge inverters. The topology fed with multiple voltage sources formed by separate PV strings with MPPT charge controllers and associated batteries. Here the topologies are analyzed for different switch open circuit and/or source failures. The switching redundancy of the proposed inverters is utilized during fault condition for supplying power with lower voltage level so that critical loads are not affected. In general, the power generation in the individual PV systems may not be same at all the times, because of partial shading, local hotspots, wrong maximum power point tracking, dirt accumulation, aging etc. To address this issue energy balancing between individual sources is taken care with the help of redundant switching combinations of proposed five-level inverter carried out in second work. Because of partial shading the associated batteries with these panels will charge and discharge unevenly, which results voltage difference between terminal voltages of sources because of SOC difference. The energy balance between batteries is achieved for all operating conditions by selecting appropriate switching combination. For example during partial shading the associated battery with low SOC is discharged at slower rate than the battery with more SOC until both SOC’s are equal. This also helps in minimization of DC offset into the ac side output voltage. The mathematical analysis is presented for possible percentage of energy shared to load by both the sources during each voltage level. The third work provides single phase multilevel inverter with improved fault tolerance in terms of switch open circuit failures and energy balancing between sources. Generally multilevel inverters for photovoltaic (PV) applications are fed ix with multiple voltage sources. For majority of the multilevel inverters the load shared to individual voltage sources is not equal due to inverter structure and switching combination. This leads to under-utilization of the voltage sources. To address this issue optimal PV module distribution for multilevel inverters is proposed. Mathematical analysis is carried out for optimal sharing of PV resources for each voltage source. The proposed source distribution strategy ensures better utilization of each voltage source, as well as minimizes the control complexity for energy balancing issues. This topology requires four isolated DC-sources with a voltage magnitude of Vdc/4 (where Vdc is the voltage requirement for the conventional NPC multilevel inverter). These isolated DC voltage sources are realized with multiple PV strings. The operation of proposed multilevel single phase inverter is analyzed for different switch open-circuit failures. All the presented topologies are simulated using MATLAB/Simulink and the results are verified with laboratory prototyp
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