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Search Results: 1 - 10 of 223878 matches for " R.Valarmathi "
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Harmonic Analysis of Distributed PV System Under High and Low Irradiance
International Journal of Engineering and Technology , 2010,
Abstract: This paper presents a unique modelling of harmonics and comparison between high irradiance and low irradiance in PV system connected to a grid. The signals used are actual tested waveforms in a distributed PV system. The percentage error has been calculated for the individual parameters in both cases. The comparative study using Chirp Z transform (CZT) with 7 term B Harris Window will enable to model harmonics using this algorithm in the future. The paper shows the performance of the method proposed in different measurement conditions.
Akilandeswari .S,R.Senthamarai,,Prema.S,,R.Valarmathi
International Journal of Pharma Sciences and Research , 2010,
Abstract: Phytochemical investigations, Antibacerial and antifungal activity studies for leaf extracts of Sida acuta were carried out. Two common solvents i.e Chloroform and Ethanol (95%) were used successively for extraction of active principles from the dried powdered leaves. The Phytochemical tests of extracts revealed the Presence of Carbohydrates, Alkaloids, Phytosterols, Saponins and fixed Oils.The antimicrobial screening was done with two Gram +ve (Staphylococcus aureus NCIM 2079, Bacillus subtilis NCIM 2063) and two Gram –ve (E.coli NCIM 2065 Pseudomonas aeruginosa NCIM 2036) bacteria and fungi (Candida albicans NCIM 3102, Aspergillus niger NCIM 1054) as test microorganisms. All the three microorganisms were markedly effected by both the extracts under study.
R. Valarmathi et al.
International Journal of Pharmaceutical Sciences and Research , 2011,
Abstract: The potential antioxidant effect ethanol induced liver damage was investigated using crude methanolic extract of the whole plant of Mollugo pentaphylla Linn. The standard drug used was ascorbic acid mg / kg/day. Serum cholesterol, triglycerides aspartate amino transferase (AST) and alanine amino transferase (ALT) levels were measured as antioxidant indicators. There was a significant reduction in the elevated serum enzymes, triglycerides and total cholesterol levels. The histopathologial studies revealed that the liver cells undergoing hydrobic and fatty changes indicating hepato cellular damage in the case of ethanol administration while extract treated animals showed mostly normal hepatocytes and mild hydrobic changes. Hence the study concluded that the plant exhibits antioxidant property.
Simulation and Analysis of Wind Energy and Photo Voltaic Hybrid System
R. Valarmathi,S. Palaniswami,N. Devarajan
International Journal of Soft Computing & Engineering , 2012,
Abstract: This paper models a hybrid system consisting of a wind turbine and a photovoltaic array as main energy sources and this is simulated using MATLAB. To connect the PV system to the grid the only adaptation required is to adjust the DC bus voltage to the conventional/isolated grids characteristics. Both energy sources are parallely linked to a common PWM voltage source inverter through individual AC/DC and DC/DC converters. A AC/DC converter transforms the 3 phase variable frequency wind turbine AC power, into variable DC power. A DC/DC converter controls variable power from the solar array DC. Though all sources have their individual controllers they have a common configuration. A VLSI based fuzzy logic controller ensures constant voltage needed for the load through the convertor’s PWM signals. The wind turbine and photovoltaic array voltage are controlled through error signal which is fed to the controller to generate pulses for the dc-dc converter. Simulation results reveal that the hybrid system provides a constant power to the load.
Genetically Modified Crops: Insect Resistance
A. Karthikeyan,R. Valarmathi,S. Nandini,M.R. Nandhakumar
Biotechnology , 2012,
Abstract: Insect pests have become an integral part of agricultural crops worldwide. They significantly reduce yield and affect almost every aspect of the plants. For many years major challenge for scientists has been developing the resistant varieties against pests in plants. Plant breeders have also been successful during the last century in producing a few Insect-resistant cultivars/lines of some potential crops through conventional breeding, but this again has utilized modest resources. However, this approach seems now inefficient due to a number of reasons and alternatively, genetic engineering for improving crop pest and disease resistance is being actively followed these days by the plant scientists, world-over. New tools and genes have been developed for use in the genetic engineering of plants to introduce effective resistance to biotic stresses and to understand the mechanisms of resistance. Recent advances in genetic engineering, Bacillus thuringiensis (Bt) has resulted in successful control of many economically important pests in food crops. This approach should allow increases in both productivity and quality of plants in an environmentally friendly manner, thereby reducing the use of and reliance on chemical control of pests.
R. Valarmathi,A. Rajendran,S. Akilandeswari,V.N. Indu latha
International Journal of Pharma Sciences and Research , 2011,
Abstract: Liver damage caused by pathogen as well as chemical reagents are of similar nature and a proper treatment regime is absent for both. Most of the hepato toxic chemicals damage liver cells mainly by inducinglipid peroxidation and other oxidative damages. Lack of allopathic medicine for the cure of hepatic injury exhorted the scientist to explore herbal medicine. Thus we have attempted to establish the hepatoprotective potency if Mollugo cerviana. In the present investigation we examined the hepato protective activity alcoholicextract of Mollugo cerviana on CCl4 induced hepato toxicity. The results revealed that all the enzymes were significantly increased in rats treated with CCl4 compared with control rats. Silymarin (25 mg / kg) was used as positive control. Mollugo cerviana treated rats also showed a marked increase in activities of antioxidant enzymes. The increased activities of these enzymes antioxidant defenses and hence increased scavenging of free radicals and decreased lipid peroxidation. The presence of flavonoids compound in the extract may be responsible for the significant hepatoprotective property.
A Priority Based Bandwidth Reservation Protocol for Wireless Mesh Networks
K. Valarmathi,N. Malmurugan
International Journal of Computer Science Issues , 2012,
Abstract: In wireless mesh networks, when compared with traditional applications, multimedia application requires the need of inflexible Quality of services (QoS) for high speed digital audio and videos. Under such a condition, the need of proper resource allocation is extremely handy. In this paper, we propose to develop a Priority Based Bandwidth Reservation Protocol (PBRP) for wireless mesh networks. Our protocol consists of two phases namely Bandwidth Request phase and Bandwidth Reply phase. In the former Phase, a Bandwidth Request (BREQ) message is forwarded from the node that requests the admission of a new traffic flow to its destination. In the later Phase, a Bandwidth Reply (BREP) message proceeds backwards, hop-by-hop, from the destination node to the node that originated the request along the path laid down by the corresponding (BREQ) message. The destination node precedes the reply according to the priority of traffic classes and reserves the bandwidth on the reply path. By simulation results, we show that our proposed protocol achieves high bandwidth utilization and throughput with reduced delay, when compared with existing technique.
Knowledge of nurses towards dengue fever in a tertiary care teaching hospital in Nepal
S Valarmathi,S Parajulee
Journal of College of Medical Sciences-Nepal , 2013, DOI: 10.3126/jcmsn.v9i1.9667
Abstract: Background:? Nurses are important health care professionals and should have wide knowledge about common diseases especially infectious diseases like dengue. Dengue is associated with shock and can lead to death. Aim:? To assess the knowledge of nurses regarding dengue fever and to study the association between the demographic variables. Setting and design:? A cross sectional study was conducted at the College of Medical Sciences-Teaching Hospital, Nepal among the nurses during December, 2010. Study tool:? Semi structured question was prepared to assess the knowledge of nurses in which there was objective question and Yes or No type questionnaire. Statistical analysis:? The filled questionnaires were collected and data were entered in Microsoft excel sheet and analyzed as per study objectives. Descriptive statistic was used to calculate the median (IQR) and non parametric tests (Kruskal Wallis test and Mann Whitney test) to compare the total scores with demographic profile of the subjects. Results:? Of the study members 89% were from Proficiency Certificate level (PCL) background and the mean (IQR) age of the respondents was 21 years (20-22.75). Overall score of the nurses was 11 (9-13) with a maximum possible score of 17. There were no association between the respondents knowledge scores with age (p=0.14); educational qualifications (p=0.86); duration of experience (p=0.59); ward (p=0.28). Conclusion:? The study findings report a low knowledge among the nursing practitioners on dengue fever and its complications and their knowledge did not have any association with their demographic variables. Journal of College of Medical Sciences-Nepal, 2013, Vol-9, No-1, 7-13 DOI: http://dx.doi.org/10.3126/jcmsn.v9i1.9667
Knowledge of nursing students towards HIV/AIDS in Nepal
Sita Parajulee,Valarmathi Selvaraj
Journal of College of Medical Sciences-Nepal , 2012, DOI: 10.3126/jcmsn.v8i4.8697
Abstract: Aims First case of Acquired Immuno Deficiency Syndrome (AIDS) in Nepal was reported in the year 1988. Nurses are an integral part of the healthcare system and should be knowledgeable in providing care to AIDS patients. This study assessed the knowledge of nursing students towards HIV/AIDS, and the association (if any) between the knowledge scores of the nursing students with their selected demographic variables. Materials and methods A cross sectional study was conducted evaluating the nursing student knowledge using a self designed questionnaire. The correct answers were given a score of ‘1’ and wrong answers were given a score of ‘0’ (total possible maximum score ‘18’). Results Among the total 165 nursing students, 121 of them filled the questionnaire (response rate of 73.33%) and all of them were females. The mean ± SD age of the respondents was 18.3 ±1.75 years. The median (IQR) of the overall total scores was 13.0 (11.5-15.0). There was an association between the knowledge scores of the respondents with ‘age’ (p=000), ‘course of the study’ (p=0.001). However, there was no statistically significant association between the knowledge scores with the ‘year of study’ of the respondents (p=0.109), ‘mode of finance’ (0.611) and ‘native’ of the students (0.173). Conclusion The study suggested that nursing students have a poor overall knowledge on AIDS and especially areas such as post exposure prophylaxis.The findings also suggested the need for providing adequate knowledge to the students during their regular class room teaching and clinical postings. Journal of College of Medical Sciences-Nepal, 2012, Vol-8, No-4, 27-33 DOI: http://dx.doi.org/10.3126/jcmsn.v8i4.8697
Joint Design of Congestion Control Routing With Distributed Multi Channel Assignment in Wireless Mesh Networks
K. Valarmathi,N. Malmurugan
Computer Science , 2010,
Abstract: In Wireless Mesh Networks (WMN), a channel assignment has to balance the objectives of maintaining connectivity and increasing the aggregate bandwidth. The main aim of the channel assignment algorithm is to assign the channels to the network interfaces, from the given expected load on each virtual link. From the existing work done so far, we can examine that there is no combined solution of multi-channel assignment with routing and congestion control. In this paper, we propose a congestion control routing protocol along with multi-channel assignment. We use a traffic aware metric in this protocol in order to provide quality of service. The proposed protocol can improve the throughput and channel utilization to very high extent because it provides solution for multi-channel assignment and congestion control. The proposed algorithm assigns the channels in a way that, congestion is avoided and co-channel interference levels among links with same channel are reduced. By our simulation results in NS2, we show that the proposed protocol attains high throughput and channel utilization along with reduced latency.
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