446 research outputs found
Electrochemical behaviour of Solanum trilobatum plant extract on stainless steel in natural sea water environment
No full textAbstract In the present work, inhibition efficacy of Solanum trilobatum leaves (STL) extract on the corrosion of stainless steel in natural sea water environment is studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. Results from the study indicate that the inhibition efficiency increased with increase of inhibitor concentration and achieved maximum of more than 80% for polarization as well as impedance measurements. Electrochemical measurements show that both polarization and charge transfer resistances increases with increase of inhibitor concentration. The adsorption of STL inhibitor on the stainless steel surface obeys Frumkin adsorption isotherm and the calculated values of ∆G ads indicate that the adsorbed layer is spontaneous and stable one. Key words: Electrochemical, inhibition, stainless steel and Frumkin Cite this article as: Deepa Rani P,Selvaraj S. Electrochemical behaviour of Solanum trilobatum plant extract on stainless steel in natural sea water environment. Annalen der Chemischen Forschung. 2013;1(3):1-9
Analytical Solutions of Second Order Nonlinear Ordinary Differential Systems with high Order Nonlinearity
No full textThis thesis is submitted to the Department of Mathematics, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Mathematics, January 2016.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 25-30).Nonlinear oscillator models have been widely used in many areas of physics and engineering and are of significant importance in mechanical and structural dynamics for the comprehensive understanding and accurate prediction of motion.
The aim of the present study is to solve the second order autonomous Nonlinear Differential Systems with strong and high ((9th)) order nonlinearity in presence of small damping by combing He’s homotopy perturbation and the extended form of the KBM methods. The results obtained by the presented method are compared with those solutions obtained by the fourth order Runge-Kutta method in graphically.Deepa Rani GhoshMaster of Science in Mathematic
Inhibitive and Adsorption Properties of Punica granatum Extract on Brass in Acid Media
No full textThe inhibition efficacy of Punica granatum extract on the corrosion of Brass in 1N HCl has been studied by mass loss measurments at various time and temperature. The inhibition efficiency is markedly higher in HCl environment with addition of Punica granatum extract compared with those in the inhibitor free solution. The inhibition efficiency increased with increase of inhibitor concentration but decreased with rise in temperature and time. Based on the values of activation energy, free energy of adsorption and variation of inhibition efficiency with temperature, a physical adsorption mechanism is proposed for the adsorption of Punica granatum on the surface of Brass. It is found to follows Langmuir and Fremkin adsorption isotherms. The alcoholic extract of bio-inhibitor and the corrosion product (with inhibitor) is analysed by UV, IR and XRD studies leads to the bio-inhibitor as an adsorption inhibitor. Key words: Corrosion inhibition, Brass, Punica granatum, Isotherm P. Deepa Rani and S. Selvaraj. Inhibitive and Adsorption Properties of Punica granatum Extract on Brass in Acid Media. J Phytol 2/11 (2010) 58-6
Computational chemistry and molecular modeling : principles and applications / K.I. Ramachandran, G. Deepa, K. Namboori.
No full text"An exclusive URL (http://www.amrita.edu/cen/ccmm/) for this book with the required support materials has been provided for readers ..."--Preface.pharmacy bookfair2015Includes bibliographical references and index.xxi, 397 pages
Micro-raman spectroscopy of caries lesion formation in dental enamel
No full textCaries lesions form by a complex process of chemical interactions between dental enamel and its environment. They can cause cavities and pain, and are expensive to fix. Lesions form by slow demineralization over many months, even years. It is hard to characterize in vivo as a result of environmental factors and remineralization by ions in the oral cavity. In this thesis the process of demineralization was carried out in vitro and micro-Raman spectroscopy used to investigate and characterize the lesion's chemistry. Demineralization occurs by diffusion across the depth of the lesion of mineral ions via interstitial spaces in the dental enamel. Hydroxyl ions are initially lost by acidic attack, which increases the interstitial space. The demineralization is retarded by diffusion processes in the opposite direction, and a balance in the charges of the ions must be maintained. Having multiple ions diffusing simultaneously is termed “coupled diffusion”. A subsurface highly demineralized region is formed, but this can be remineralized.
Micro-Raman spectroscopy is a powerful tool for studying material composition by exciting chemical bonds in the sample. Using micro-Raman to characterize the chemical composition of lesions may help in developing preventative measures to stop their formation. Raman (λ=785 nm) was used to characterize lesions grown over 5, 7, 9, 11 and 14 days. The amide I peak at ~1605 cm-1, which has not been observed previously, was seen in the maturing lesions. The extreme demineralization in these lesions enables the organic peaks to be seen rather than the normally stronger mineral peaks. Analysis of crystallinity shows that there is always a reduction in mineral content with distance below the enamel surface, but this becomes magnified as the lesion matures. Type B carbonate substitution for phosphate ions can also be examined with Raman. Correcting for crystallinity shows that both carbonate and phosphate ions are lost at the same rate during demineralization.
In summary, micro-Raman is an effective and relatively easy tool to use in lesion characterization. It also has the advantage that it can be used to identify changes in both the mineral and protein phases of enamel.M.S.Includes bibliographical references (p. 53-55)
Comparison of best medical management with carotid intervention procedures in the prevention of stroke recurrence in patients with symptomatic internal carotid artery stenosis
No full textBackground: As per the current recommendations, carotid interventional procedures (carotid endarterectomy/carotid artery stenting) are considered superior to medical management in reducing the stroke recurrence in patients with symptomatic extracranial internal carotid artery (ICA) stenosis. Objective: The objective of this study is to compare the best medical management with carotid interventional procedures in the prevention of stroke recurrence in the patients with symptomatic extracranial ICA stenosis. Materials and Methods: This was a parallel, prospective, two-arm, open-label, observational study. Participants were selected consecutively and prospectively among patients from Outpatient and Inpatient Departments of Neurology at Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India. The study period was from January 2012 to December 2017. Results: Of 150 patients with symptomatic extracranial ICA stenosis of ≥50%, 100 preferred best medical management (m = 75, f = 25) and 50 (m = 37, f = 13) opted for carotid intervention. The mean age of the patient cohort was 59.8 ± 12.7. Follow-up was done at regular intervals from 3 months to 1 year. In the medical group, the recurrence occurred in 10 patients; 4 (40%) within 6 months, 5 (50%) within 6–12 months, and 1 (10%) after 1 year. In the intervention group, the recurrence occurred in 6 patients; 5 (83%) within the first 6 months and 1 (17%) within 6–12 months. Conclusions: Overall, there was no statistically significant difference in the rate of recurrence between the best medical management and the carotid interventional procedures
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Associations between sleep, obesity, and asthma in urban minority children.
No full textSTUDY OBJECTIVES: Although obesity, asthma, and sleep-disordered breathing are interrelated, there is limited understanding of the independent contributions of body-mass index and pulmonary function on polysomnography in children with asthma. METHODS: We conducted a retrospective chart review on 448 7- to 18-year-old children with asthma who had undergone polysomnography testing between 1/2007-12/2011 to elucidate the association between spirometry variables, body-mass index, and polysomnography parameters, adjusting for asthma and antiallergic medications. RESULTS: Obese children had poorer sleep architecture and more severe gas exchange abnormalities compared to healthy weight children. Multivariate analysis revealed an independent association of body-mass index with sleep efficiency, with more light and less deep sleep in both obese and healthy-weight children, and with baseline oxygen saturation and oxygen nadir in obese children. In obese children, forced vital capacity was independently associated with less deep sleep (time in N3 sleep) as well as with oxygen nadir, while among healthy-weight children, forced expiratory volume directly correlated but forced vital capacity inversely correlated with deep sleep. In obese children, inhaled corticosteroid was associated with baseline oxygen saturation, and montelukast was associated with lower end-tidal carbon dioxide. In healthy-weight children, inhaled corticosteroid was associated with arousal awakening index, and montelukast was associated with light sleep. Antiallergic medications were not independently associated with polysomnography parameters. CONCLUSIONS: Pulmonary function, body-mass index, and asthma medications have independent and differing influences on sleep architecture and gas exchange polysomnography parameters in obese and healthy-weight children with asthma. Asthma medications are associated with improved gas exchange in obese children and improved sleep architecture in healthy-weight children with asthma. CITATION: Conrad LA, Nandalike K, Rani S, Rastogi D. Associations between sleep, obesity, and asthma in urban minority children. J Clin Sleep Med. 2022;18(10):2377-2385
Corrections to “An Improved Harmonics Mitigation Scheme for a Modular Multilevel Converter” [2019 147244-147255]
No full textIn the above-named work, T. Deepa should have been listed as the second co-author of the article with the affiliation of (1): School of Electrical Engineering, Vellore Institute of Technology, Chennai 600127, India. The author's biography is also provided within this correction. Additionally, the correct zip code of affiliation (1) should be 600127, and the correct statement on financial support acknowledgement should be as follows: "This work was funded by the Renewable Energy Laboratory, Department of Communications and Networks Engineering, Prince Sultan University, Riyadh, Saudi Arabia." It is necessary to mention the nature of funding provided by Prince Sultan University and to note the correction in the spelling of the university in the same statement in the published manuscript
Creating Value Through Design: Company and Country Perspectives from East Asia
No full textFor the final Y.B. Min lecture of the semester, the Center for Asian Business welcomed Deepa Prahalad, an author and business strategist specializing in opportunities at the intersection of consumer experience, technology and strategy. In her presentation, titled “Creating Value through Design: Company and Country Perspectives from East Asia,” Prahalad discussed the role of design in creating value, the ingredients of good design and how this applies to Asian countries in particular.
Prahalad discussed the success of great brands such as Apple, Nike, Coca-Cola and Samsung and how they have created awareness of the value of design to business. Design today is an important source of strategic advantage for entrepreneurs, established companies and countries. Her talk focused on case studies of how companies and countries have used design to build brands and create a sphere of influence.
According to Prahalad, strategic challenges such as co-creation, customer experience, globalization, innovation and new business model creation all require design. Today, we’re seeing a convergence of brand and design. Leading brands such as Nike, Apple, McDonald’s and Mercedes are all identifiable by their logo alone. These brands have a distinct look, feel and experience, and the experience must be valued by the consumers. Prahalad went on to address how emotional connections often lead to business results.
At the conclusion of her lecture, she highlighted the following points: Behavior is as important as income There is a convergence of quantitative and qualitative data Looking at emotions creates obligations for companies A great design still needs a great business model
Passionate about emerging markets and innovation, Prahalad has worked as a management consultant with firms from start-ups to large multinationals. She researched and co-authored the book, Predictable Magic: Unleash the Power of Design Strategy to Transform Your Business. Prahalad speaks on design strategy and emerging markets at business schools and at global and government forums on the importance of design as a competitive innovation. Prahalad received a B.A. in Economics and Political Science from the University of Michigan and an MBA from the Tuck School of Business at Dartmouth.https://digitalcommons.lmu.edu/ybminlectureseries/1003/thumbnail.jp
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