Faculty Publications

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    Long-Term Climate Variability and Drought Characteristics in Tropical Region of India
    (American Society of Civil Engineers (ASCE), 2021) Vijay, A.; Sivan, S.D.; Mudbhatkal, A.; Mahesha, A.
    This work reports climate change signals and long-Term trend analysis of climate variables, meteorological drought, and extreme climate indexes over the tropical state of Kerala in India. The trend analysis reveals statistically significant decrease of annual and southwest monsoon rainfall (as much as 63 mm and 55 mm per decade, respectively). A decrease in number of annual rainy days (up to 2.8 days/decade) is also reported. Temperature trend analysis indicates an increasing trend with as high as 1.3°C/decade. The spatio-Temporal variation of extreme climate indexes across Kerala shows a decreasing trend of extreme precipitation indexes and an increasing trend of extreme temperature indexes. R95 and R95p decreased in northern and southern Kerala whereas R5 index increased in central and southern regions. Warm days have significantly increased whereas cold days exhibit a decreasing trend across the state. The increase in warmer nights is statistically significant whereas colder nights are decreasing in central and southern regions. Meteorological drought using Standardized Precipitation Index (SPI) reveals increasing occurrence of droughts in Kerala with higher frequencies over southern and central Kerala. © 2021 American Society of Civil Engineers.
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    Influence of oxidation on fracture toughness of carbon-carbon composites for high-temperature applications
    (Gruppo Italiano Frattura, 2021) Sunil Kumar, B.V.S.; Londe, V.N.; Lokesha, M.; Vasantha Kumar, S.N.; Surendranathan, A.O.
    Carbon-Carbon Composites (C-CC), used as composites for their remarkable qualities in the space industry and in many other industry sectors. C-CC has proven to be the most efficient material in extreme temperature situations. They are one among the best high-temperature materials with good thermal quality, such as high-temperature stability, outstanding thermal conductivity and low-temperature expansion coefficients. In aircraft, railways, trucks and even race vehicles, C-CC brake disks are in high demand. Compared to the favorable thermal and mechanical qualities of C-CC, their great sensitivity to oxidation in an oxidizing environment at temperatures even around 400°C is a major restriction with these composites. In particular, a study of the C-CC oxidation mechanism helps to create protective measures for these composites. The present experimental study explores the influence of oxidation in static air on the fracture toughness of C-CC. At a temperature of around 400°C to 700°C in an increment of 100°C, an oxidation evaluation of the material is carried out. Results show that there was a significant decrease in the fracture toughness when there was an increase in temperature from 400°C to 700°C. We can observe that C-CC fracture toughness is severely affected by oxidation. The decrease in the fracture toughness value in comparison with room temperature was 6% for 400°C and 45% for 700°C. © 2021.