Browsing by Author "Ravishankar, K."

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A reliability test for the body constitution diagnosis using wrist pulse analysis based on ayurveda
(National Institute of Science Communication and Policy Research, 2022) Sukesh Rao, M.; Ravishankar, K.; Rao, R.
Wrist pulse diagnosis is the most primitive and apparent way to know about the human body condition for the diagnosis of disease. Ayurveda, an ancient Indian science, introduced wrist pulse diagnosis in the name of 'Nadi'. Due to the lack of expertise and standardisation, the knowledge of Nadi is limited to very few Ayurvedic practitioners. An automated wrist pulse reading instrument can overcome this problem and help in non-invasive diagnosis using a wrist pulse based on Ayurveda. The primary objective of the research is to develop instrumentation to digitise the three pulse patterns viz., Vata (V), Pitta (P) and Kapha (K). Based on the signals acquired, the nature of the body (Prakriti) is identified and categorised into different classes. Wrist pulses are acquired using three thin-film flexible piezoelectric sensors and processed using a signal conditioning circuit. Signals are quantised using data acquisition module and processed. The studies carried out in the present work show substantial to moderate (based on the number of classes considered) agreement in the pulse-based classifications done by expert Ayurvedic physician and the developed instrument. Cohen's kappa of 0.719 and 0.454 are obtained as inter-rater reliability between traditional and instrumental readings on wrist pulse taken on basic level (VPK) and sub-levels (VP, VK PK). An inter-rater reliability test using Cohen's Kappa is adopted for this purpose. Similarly, reliability between Ayurvedic questionnaire-based and wrist pulse-based Prakriti identification are also tested. A Cohen's kappa of 0.587 and 0.476 is obtained between Prakriti and two different pulse reading data sets with basic level of classification viz. instrument and traditional method. © 2022, National Institute of Science Communication and Policy Research. All rights reserved.
Flexural strength of hydrogen plasma-treated polypropylene fiber-reinforced polymethyl methacrylate denture base material
(2018) Mathew, M.; Shenoy, K.; Ravishankar, K.
Objectives: The present study aimed to evaluate flexural strength of hydrogen plasma-treated polypropylene fibers-reinforced polymethyl methacrylate (PMMA) polymer composite. Materials and Methods: One control group with no fiber reinforcement and 9 polymer composite test groups with varying fiber weight percentage (2.5, 5, and 10 Wt%) and aspect ratio (3/220, 6/220, and 12 mm/220 ?m) were prepared. Flexural strength was measured using Instron. Results: All hydrogen plasma-treated polypropylene fiber-reinforced test groups obtained significantly higher flexural strength characteristics. Among the test groups, 6 mm long fibers reinforced in 10 Wt% showed superior flexural strength. Conclusion: Hydrogen plasma treatment on polypropylene fiber has a significant role in enhancing the adhesion between PMMA polymer matrix and the polypropylene fibers and thereby the flexural strength. 2018 The Journal of Indian Prosthodontic Society | Published by Wolters Kluwer - Medknow.
Flexural strength of hydrogen plasma-treated polypropylene fiber-reinforced polymethyl methacrylate denture base material
(Wolters Kluwer Medknow Publications B9, Kanara Business Centre, off Link Road, Ghatkopar (E) Mumbai 400 075, 2018) Mathew, M.; Shenoy, K.; Ravishankar, K.
Objectives: The present study aimed to evaluate flexural strength of hydrogen plasma-treated polypropylene fibers-reinforced polymethyl methacrylate (PMMA) polymer composite. Materials and Methods: One control group with no fiber reinforcement and 9 polymer composite test groups with varying fiber weight percentage (2.5, 5, and 10 Wt%) and aspect ratio (3/220, 6/220, and 12 mm/220 ?m) were prepared. Flexural strength was measured using Instron. Results: All hydrogen plasma-treated polypropylene fiber-reinforced test groups obtained significantly higher flexural strength characteristics. Among the test groups, 6 mm long fibers reinforced in 10 Wt% showed superior flexural strength. Conclusion: Hydrogen plasma treatment on polypropylene fiber has a significant role in enhancing the adhesion between PMMA polymer matrix and the polypropylene fibers and thereby the flexural strength. © 2018 The Journal of Indian Prosthodontic Society | Published by Wolters Kluwer - Medknow.
Impact analysis of natural fiber and synthetic fiber reinforced polymer composite
(American Institute of Physics Inc. subs@aip.org, 2018) Sangamesh, R.; Ravishankar, K.; Kulkarni, S.M.
Impact analysis of the composite structure is essential for many fields like automotive, aerospace and naval structure which practically difficult to characterize. In the present study impact analysis of carbon-epoxy (CE) and jute-epoxy (JE) laminates were studied for three different thicknesses. The 3D finite element model was adopted to study the impact forces experienced, energy absorption and fracture behavior of the laminated composites. These laminated composites modeled as a 3D deformable solid element and an impactor at a constant velocity were modeled as a discrete rigid element. The energy absorption and fracture behaviors for various material combinations and thickness were studied. The fracture behavior of these composite showed progressive damage with matrix failure at the initial stage followed by complete fiber breakage. Â© 2018 Author(s).
Influence of High Mn-Cu-Mo on Microstructure and Fatigue characteristics of Austempered Ductile Iron
(Institute of Physics Publishing helen.craven@iop.org, 2018) Banavasi Shashidhar, M.; Ravishankar, K.; Naik Padmayya, S.
The impacts of high Mn content on microstructure and fatigue characteristics of ADI at 300, 350 and 400 Â°C for 120 min have been examined. Optical microscopy images reveals bainite morphology only at 300Â°C. Higher Mn contents hinders bainite transformation in the locales of Mn and Mo segregation, where in stage II reaction initiates near the graphite nodules before stage I reaction ends away from the nodules which creates more unreacted austenite volume after cooling forming martensite around the periphery creating austenite-martensite zone at 350 Â°C and tremendously articulated at 400Â°C. Feathery ferrite laths, stable retained austenite and uniform density hardness in the matrix, promotes higher toughness and fatigue properties (250 MPa @ 106 cycles) at 300 Â°C. Presence of stage II carbides in the eutectic cell and austenite-martensite zone in the intercellular regions, due to their embrittlement in the matrix, makes easy crack path for initiation and propagation deteriorating properties at 350Â°C and above. SEM images of fatigue fractured surface revealed that at 300Â°C, showed a regular crack interconnecting graphite nodule, fatigue striation and quazi-cleavage fracture mode, and at 350 & 400Â°C reveals the carbide, austenite-martensite and porosity/defect final fracture region. Â© Published under licence by IOP Publishing Ltd.