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Search Results: 1 - 10 of 401336 matches for " M. Shyamala "
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The Inhibitory Action of the Extracts of Adathoda vasica, Eclipta alba, and Centella asiatica on the Corrosion of Mild Steel in Hydrochloric Acid Medium: A Comparative Study
M. Shyamala,P. K. Kasthuri
International Journal of Corrosion , 2012, DOI: 10.1155/2012/852827
Abstract: The Inhibitive action of the extracts of Adathoda vasica, Eclipta alba, and Centella asiatica on the corrosion of mild steel in 1N HCl has been studied using weight loss method, electrochemical methods, and hydrogen permeation method. Polarization method indicates that the plant extracts are under mixed control, that is, promoting retardation of both anodic and cathodic reactions. The impedance method reveals that charge-transfer process controls the corrosion of mild steel. The plant extracts obey Langmuir adsorption isotherm. Theoretical fitting of the corrosion data to the kinetic-thermodynamic model was tested to show the nature of adsorption. Physisorption mechanism has been proposed for the inhibition action of these plant extracts. The protective film formed on the surface was confirmed by SEM. From hydrogen permeation method, all the plant extracts were able to reduce the permeation current. Results obtained in all three methods were very much in good agreement in the order Eclipta alba > Adathoda vasica > Centella asiatica, and, among the three plant extracts studied, the maximum inhibition efficiency was found in Eclipta alba which showed 99.6% inhibition efficiency at 8.0% v/v concentration of the extract. 1. Introduction Mild steel was the material of choice due to its characteristics of wide application in motor car bodies, machines, gears, pipes, tanks, and so forth and in most of the chemical industries. Hydrochloric acid and sulphuric acids are the medium generally being used for pickling mild steel. About 90% of pickling problems can be solved by introducing appropriate pickling inhibitor to the medium. The recent and growing trend is using plant extracts as corrosion inhibitor. Owing to strict environmental legislation, emphasis is being focused on development of naturally occurring substances as corrosion inhibitors [1]. Recently, many plant extracts have been reported to be very effective corrosion inhibitors for the protection of mild steel in acidic media [2–19]. In this study, the inhibition effect of the leaf extracts of Adathoda vasica (Adathodai), Eclipta alba (Karisalankanni), and Centella asiatica (Vallarai) on the corrosion of mild steel in 1N hydrochloric acid was investigated using weight loss method, electrochemical methods, and hydrogen permeation method. There was no literature report on the studies of corrosion inhibition effect of the above plant extracts on mild steel in hydrochloric acid medium previously. From literature survey, it were found that the six plants selected for investigation was found to contain some
A Comparative Study of the Inhibitory Effect of the Extracts of Ocimum sanctum, Aegle marmelos, and Solanum trilobatum on the Corrosion of Mild Steel in Hydrochloric Acid Medium
M. Shyamala,P. K. Kasthuri
International Journal of Corrosion , 2011, DOI: 10.1155/2011/129647
Abstract: A comparative study of the inhibitory effect of plant extracts, Ocimum sanctum, Aegle marmelos, and Solanum trilobatum, on the corrosion of mild steel in 1N HCl medium was investigated using weightloss method, electrochemical methods, and hydrogen permeation method. Polarization method indicates plant extracts behave as mixed-type inhibitor. The impedance method reveals that charge-transfer process mainly controls the corrosion of mild steel. On comparison, maximum inhibition efficiency was found in Ocimum sanctum with 99.6% inhibition efficiency at 6.0%?v/v concentration of the extract. The plant extracts obey Langmuir adsorption isotherm. The SEM morphology of the adsorbed protective film on the mild steel surface has confirmed the high performance of inhibitive effect of the plant extracts. From hydrogen permeation method, all the plant extracts were able to reduce the permeation current. The reason for the reduced permeation currents in presence of the inhibitors may be attributed to the slow discharge step followed by fast electrolytic desorption step. Results obtained in all three methods were very much in good agreement in the order Ocimum sanctum > Aegle marmelos > Solanum trilobatum. 1. Introduction Mild steel is a structural material widely used in automobiles, pipes and used in most of the chemical industries. Mild steel suffers from severe corrosion in aggressive medium of acids and pickling processes. Hydrochloric acid is widely used for pickling, descaling, and chemical cleaning processes of mild steel. 90% of pickling problems can be solved by introducing appropriate pickling inhibitor to the medium. Generally, organic compounds containing O, N, and S atoms are normally used as inhibitors to reduce the corrosion of mild steel in hydrochloric acid medium [1, 2]. Environmental concerns worldwide are increasing and are likely to influence the choice of corrosion inhibitors in the present and in future. Environmental requirements are still being developed, but some elements have been established. One of the methods to protect metals against corrosion is addition of species to the solution in contact with the surface in order to inhibit the corrosion rate. Unfortunately, many of the inhibitors used are inorganic salts or organic compounds with toxic properties or limited solubility. Increasing awareness of health and ecological risks has drawn attention to find more suitable inhibitors which are nontoxic. Accordingly, greater research efforts have been directed towards formulating environmentally acceptable inhibitors. Due to the diversity of
Physicochemical Analysis of Borewell Water Samples of Telungupalayam Area in Coimbatore District, Tamilnadu, India
R. Shyamala,M. Shanthi,P. Lalitha
Journal of Chemistry , 2008, DOI: 10.1155/2008/152383
Abstract:
Production and Optimization of Indole Acetic Acid by Indigenous Micro Flora using Agro Waste as Substrate
M. Sudha,R. Shyamala Gowri,P. Prabhavathi,P. Astapriya
Pakistan Journal of Biological Sciences , 2012,
Abstract: Indole Acetic Acid (IAA) producing bacterium was isolated from the Rhizosphere soil and identified as Rhizobium sp. and Bacillus sp., Optimization of Indole acetic acid production was carried out at different cultural conditions, such as pH, temperature and substrate with Rhizobium sp., Bacillus sp. and Rhizobium sp., produced higher amount of Indole acetic acid (6.1 mg mL-1) than the Bacillus sp., (4.4 mg mL-1) at pH 7 and 37C in the Bengal gram substrate. Partial purification of Indole acetic acid was done by Thin Layer Chromatography (TLC). In conclusion Rhizobium sp., appear to be a suitable soil microorganism for high level of IAA production.
Economics Of Water Management
A. Shyamala
Golden Research Thoughts , 2012, DOI: 10.9780/22315063
Abstract: Water management depends on the interrelationship between a variety of factors including irrigation practices, land use and cropping pattern, individual and collective system of irrigation and overall economics. The saving of water is extremely complex since the development, operation and maintenance of the water supply system is the responsibility of the government, but the saving of water can only be obtained with the full cooperation of the farmers. The total water obtained as rain in the entire country works to about 400 m. ham per annum. The area irrigated at present in India is 25 per cent of the sown area and it is expected to increase to about 52 per cent of the cropped area in the year AD 2025.
THE ROLE OF CORONARY ANGIOGRAPHY IN ASSESING THE CLINICAL SEVERITY OF CORONARY ARTERY DISEASE
shyamala kumari
International Journal of Biomedical and Advance Research , 2012, DOI: 10.7439/ijbar.v3i5.387
Abstract: Introduction: We can presume that risk factors are predictive of the degree of anatomical impairment on coronary angiography in coronary artery disease. In the present study, an attempt has been made to address whether the coronary angiography alone is potentially be able in assessing the clinical severity of patients with ACS or can we include the risk factors also in this issue. Methods: 100 Patients with established CAD were divided into 4 groups based on the angiography &clinical severity. Body mass index (B.M.I.), Waist circumference& Waist a€“ hip ratio was calculated. Data collected was then analyzed in relation to the angiographic severity and the clinical presentation using Pearsona€ s chi square test and Analysis of Variance, using SPSS (Statistical Package for the Social Sciences). P value of less than 0.05 was considered as statistically significant. Result: Obesity is the highest common risk factor. Majority of the patients, i.e. 80 %, in study group had more than 2 risk factors. When angiographic severity was compared with total number of risk factors, the incidence of triple vessel disease was more with multiple risk factors, but this observation did not reach a point of statistical significance (p = 0.38). Conclusion: Angiographic severity could not predict the clinical manifestation with much precision. In view of such high prevalence of risk factors, it seems appropriate that we, as clinicians, should look for other possible risk factors in a given patient and manage them aggressively Key words: CAD angiogram BMI W/H ratio urine albumin
Dielectric and Optical Characterization of Boron Doped Ammonium Dihydrogen Phosphate  [PDF]
Delci Zion, Shyamala Devarajan, Thayumanavan Arunachalam
Journal of Crystallization Process and Technology (JCPT) , 2013, DOI: 10.4236/jcpt.2013.31002
Abstract:

Single crystals of pure and boron doped ammonium dihydrogen phosphate were grown from aqueous solution by slow solvent evaporation process. ICP studies were done to confirm the presence of the dopant boron in the parent crystal. The values of the lattice parameters were determined by single crystal X-ray diffraction. The pure and doped ADP crystals were found to have tetragonal structure. Complete optical characterizations of the crystals were done using the FTIR, UV-Vis and NLO studies. The presences of the various functional groups in the crystals were identified by FTIR spectrum. The band gap energies of the pure and doped crystals have been calculated at their cut off frequencies using the UV-Vis spectrum. The second harmonic generation efficiency of the crystals was determined. The electric properties of the grown crystal have been analyzed by studying the variation of dielectric constant and dielectric loss with frequency.

A Prospective Pilot Study to Validate the Management Protocol for Patients Presenting with Acute Urinary Retention: A Community-Based, Nonhospitalised Protocol
Shyamala S. Gopi,Chris M. Goodman,Allison Robertson,Derek J. Byrne
The Scientific World Journal , 2006, DOI: 10.1100/tsw.2006.379
Abstract:
NPAS IN INDIAN BANKING SECTOR: IMPACT ON PROFITABILITY
Dr. A. Shyamala
Indian Streams Research Journal , 2012,
Abstract: The level of NPA act as an indicator viewing the bankers credit risks and competence of allocation of resource. Non-performing Asset is an important factor in the analysis of financial performance of a bank as it results in decreasing boundary and higher provisioning requirement for doubtful debts. The Narasimhan Committee has suggested prudential norms on income recognition, asset classification and provisioning. In alter from the history; Income recognition is now not on an addition basis but when it is essentially received. Past problems faced by banks were to a great extent attributable to this. Classification of what an NPA is has changed with narrowing of prudential norms. At present an asset is "non-performing" if interest or installments of principal due stay unpaid for more than 180 days. To improve the efficiency and profitability, the NPA has to be scheduled. Various steps have been taken by government to reduce the NPA. The study finally viewed that the prudential norms and other schemes has rushed banks to improve their performance and accordingly resulted into orderly down of NPA as well as enhancement in the financial strength of the Indian banking structure.
Performance Comparison of Routing Attacks in Manet and WSN
Shyamala Ramachandran,Valli Shanmugam
International Journal of Ad Hoc, Sensor & Ubiquitous Computing , 2012,
Abstract: Routing is a basic step for data exchange. In wireless ad-hoc networks each node acts as a router and executes a routing protocol. Wireless ad-hoc networks are highly resource constrained in terms of network topology, memory and computation power. The reliable data transfer is a difficult task in wireless ad-hoc networks because of resource constraints. A mobile ad-hoc network (MANET) is a kind of wireless ad-hoc network, and is a self-configuring network of mobile routers connected by wireless links. A wireless sensor network (WSN) is a highly constrained wireless ad-hoc network. In these network, multicast is the efficient routing service for data broadcasting. Denial of service (DOS) attack, sinkhole, wormhole, sybil, black hole and rushing attacks are some routing attacks. So, it is necessary to study the impact of routing attacks on existing multicast routing protocols to suggest a suitable secure multicast routing protocol. The objective of this paper is to study the effects of black hole and rushing attack on MANET and WSN. The NS-2 based simulation is used in analyzing the black hole and rushing attacks. From performance metrics such as packet delivery ratio (PDR), packet drop ratio (PDrR), network throughput (NTh) and energy consumption it is observed that the routing attacks have severe impact on MANET than WSN.
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