Browsing by Author "Kumar, B.G."

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Biodegradation of PEEK Piston Rings
(Elsevier Ltd, 2021) Shetty, P.; Dsilva, P.; Sondar, P.R.; Kumar, B.G.; Hegde, S.
Polyether ether ketone (PEEK) is considered a high performance thermoplastic with excellent mechanical, chemical, and thermal properties. It is generally believed that this material is chemically and biologically inert, and is used for various biomedical and industrial applications, especially in the form of fiber reinforced polymeric composites. Contrary to the general belief, the present work reports the biodegradation of PEEK piston rings that were used in a reciprocating CO2 compressor. A series of circumstantial and direct evidences were collected by following various tests and characterization methods to confirm the degradation of the piston rings by bacterial attack. The bacterial cells were extracted from the degraded piston rings, cultured in agar medium and then studied using scanning electron microscope. An experimental simulation was carried out by depositing and incubating a bacterial culture on the pristine surface of a PEEK specimen. The simulation experiment revealed an early stage of bacterial degradation in the form of cracking of the PEEK specimen surface. The results of various tests, characterization, and the experimental simulation presented in the paper suggest that PEEK based composites degrade due to enzymatic hydrolysis process by Myxococcus Xanthus, the rod–shaped soil bacteria. © 2021
Effect of width of gallery of highwall mining on stability of highwall: A numerical modelling approach
(2014) Ram Chandar, K.; Kumar, B.G.
Owing to continuous increased demand for coal, along with existing mining methods, some novel methods are being looked for. Highwall mining is such a method where considerable quantity of coal blocked in the highwall can be extracted to a great extent. The major challenge in highwall mining is roof control along with the stability of highwall. This method was introduced in one of the opencast coal mines first time in India. A systematic study was taken up using numerical modelling approach to assess the influence of width of gallery of highwall on stability of highwall based on field investigations. The width of gallery was taken as 3.5, 4.25 and 5.0 m. It was found that the stress and strain was more in case of 5.0 m wide gallery compared with 3.5 m wide gallery and the stress and strain values were more at the end point of galleries compared with the starting points of the galleries. The factor of safety values were decreased as the width of gallery increased from 3.5 m to 5.0 m. 2014 Inderscience Enterprises Ltd.
Effect of width of gallery of highwall mining on stability of highwall: A numerical modelling approach
(Inderscience Enterprises Ltd., 2014) Ram Chandar, K.R.; Kumar, B.G.
Owing to continuous increased demand for coal, along with existing mining methods, some novel methods are being looked for. Highwall mining is such a method where considerable quantity of coal blocked in the highwall can be extracted to a great extent. The major challenge in highwall mining is roof control along with the stability of highwall. This method was introduced in one of the opencast coal mines first time in India. A systematic study was taken up using numerical modelling approach to assess the influence of width of gallery of highwall on stability of highwall based on field investigations. The width of gallery was taken as 3.5, 4.25 and 5.0 m. It was found that the stress and strain was more in case of 5.0 m wide gallery compared with 3.5 m wide gallery and the stress and strain values were more at the end point of galleries compared with the starting points of the galleries. The factor of safety values were decreased as the width of gallery increased from 3.5 m to 5.0 m. © 2014 Inderscience Enterprises Ltd.