Faculty Publications

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    Statistical Analysis of Seismicity Parameters and Completeness Period of Earthquake Catalog for Sree Padmanabhaswamy Temple, Thiruvananthapuram District, Kerala
    (Springer Science and Business Media Deutschland GmbH, 2023) Padmanabhan, M.P.H.; Siddhardha, R.; Kolathayar, S.; Hegde, R.
    In the present study, seismicity data analysis of Sree Padmanabhaswamy Temple, Thiruvananthapuram District, Kerala, India, has been performed. The area is having a radius of 500 km with Sree Padmanabhaswamy Temple (8.48°N Latitude and 76.94°E Longitude) as the center. Earthquake catalog from 1822 to 2021 has been compiled and homogenized into equivalent moment magnitude (Mw) using regional empirical relationships. Data on earthquakes were declustered using Urhammer method to exclude foreshocks and aftershocks within a time and space window, and then statistical analysis was done to ensure data completeness. Using the Guntenberg-Ritchers recurrence relationship, the seismic parameters obtained are 1.234 and 0.532, respectively. The Mmax value calculated using Kijko’s MATLAB algorithm found to be 6.08 ± 0.26. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
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    Effect of High Temperature on the Compressional Wave Velocity of Two Sandstones with Different Grain Sizes
    (Springer Science and Business Media Deutschland GmbH, 2024) Manikanta, V.; Hasainar, H.; Badiger, N.K.; Kothari, V.; Bhat, A.; Srinivasan, V.
    Understanding rock behaviour at high temperatures can serve as vital information in restoring fire-damaged monumental structures. This knowledge is essential for engineering and construction purposes, as it allows for assessing rock stability and potential hazards and developing appropriate safety measures in areas with high temperatures. This study investigates the effect of different temperatures on two sandstones with varying grain sizes. The rock was first heated to a range of temperatures such as 35, 250, 500, 750, and 1000 °C. To identify the thermal damage of the rock samples, the Ultrasonic Pulse Velocity measurement instrument is used to identify the inner cracks. This research discusses the application of Ultrasonic Pulse velocity (UPV) to identify thermal damage and analyse related parameters of two different sandstones. The ultrasonic method is one of the simple and reliable techniques to understand the damage conditions of rocks. There were significant variations in the P-wave velocity with thermal treatment, it is observed that a negative trend developed in the primary wave velocity as the temperature increased. They give qualitative and quantitative inferences on the extent of damage caused by various environmental parameters, particularly heating. The data obtained from the present study were compared to check the confidence of regression models. The mean absolute percentage error method, the root mean square error method (RMSE), was carried out on thermal damage of rock samples. Probabilistic analysis was also conducted to estimate the damage on rocks at different confidence levels. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
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    Laboratory and theoretical evaluation of clogging behaviour of porous friction course mixes
    (2010) Suresha, S.N.; George, V.; Ravi Shankar, A.U.
    The clogging of porous friction courses (PFCs) plays a major role in their resulting performance. Clogging occurs due to deposition of external and internal materials, leading to the loss of permeability and drainage characteristics of PFCs. In this study, investigations were conducted to determine the effect of clogging and de-clogging on the permeability of PFC mixes. Tests were conducted to study the effect of three different clogging materials on PFC mixes prepared using four different aggregate gradations. Permeability tests were conducted using the falling-head concept on cylindrical PFC specimens. The influence of the particle size ratios and the effective air voids on the permeability of fresh, clogged and de-clogged PFC specimens was analysed. Experimental results on the permeability observed were compared with those predicted using theoretical models. Although, the theoretical models tend to overestimate the permeability values, statistical analyses indicate good correlations with the observed results.
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    Abrasive wear behavior of granite-filled glass-epoxy composites by SiC particles using statistical analysis
    (2011) Basavarajappa, .S.; Manjunath Yadav, S.M.; Kumar, S.; Arun, K.V.; Narendranath, S.
    This experimental investigation deals with the evaluation of abrasive wear behavior of Glass Epoxy (G-E) composites on pin-ondisc test rig. A plan of experiments, based on the Taguchi Design of Experiments, was performed to acquire data in controlled way. An orthogonal array and the analysis of variance were employed to investigate the percentage of contribution of various process parameters like sliding speed, applied load, sliding distance and their interactions affecting the abrasive wear volume loss of composites. The correlations between the various factors affecting the abrasive wear behavior of composites were obtained by using multiple linear regression equations. The obtained results indicate that applied load and sliding distance were the wear factors that have the highest physical as well as statistical influence on the abrasive wear behavior of both filled and unfilled G-E composites. A good agreement between the predicted and actual wear resistance was observed within±12%. © Taylor & Francis Group, LLC.
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    Analysis of historical trends in hydrometeorological variables in the upper Cauvery Basin, Karnataka, India
    (Indian Academy of Sciences, 2017) Kumar Raju, B.C.; Nandagiri, L.
    The present study examines the significance and magnitude of trends in the monthly rainfall, monthly mean maximum and minimum daily temperatures and streamflow in the Upper Cauvery Basin, Karnataka for a 30-year period, i.e. 1981-2010. Using observed data from 33 rain gauges, 6 climate stations and 4 stream gauging sites, statistical parameters -coefficient of variation (CV) and percentage departure have been calculated for average monthly values separately for three decades. As expected, CV of rainfall showed large variations from December to March, while the percentage departure also varies during these months for different decades. Statistically significant trend was observed in maximum temperature for Chikmagalur and Hassan stations. CV of minimum daily temperature showed large variability from November to March for all climate stations and also a significant increasing trend for Hassan and Bengaluru stations, while for Madikeri a decreasing trend was observed with a variation of -0.16°C/year. Not much variation was found for streamflow, except in K. M. Vadi and T. Narasipur gauge sites, which showed significant decreasing trend of -0.778 m3/s/year. Long-range dependence analysis revealed a weak persistence for both rainfall and streamflow of the basin. Results provide information regarding historical climate trends in the Upper Cauvery Basin, which can form the basis for projecting likely future trends and preparing plans for climate change mitigation and adaptation.