Faculty Publications

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Subject: search.filters.subject.Coastal area

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    Rainfall trend analysis in coastal region of karnataka
    (Springer Science and Business Media Deutschland GmbH, 2021) Ashwin, S.; Kemmannu, K.; Doranalu Chandrashekar, D.C.
    Climate can be defined as the weather conditions or the weather patterns that is present in the particular geographical area for a very lengthy period. It can be assessed by the important factors like temperature, humidity, wind, precipitation. The climate of the region also depends on the latitude, terrain, water bodies, etc. Coastal Karnataka receives an average rainfall of 3456 mm; at summer, the temperature lies between 33.5 and 40 °C and the minimum temperature of 23.3 and 27.9 °C. Tropical monsoon climate covers whole coastal places of Karnataka and other nearby places too. Rainfall time series is divided into four periods. This region has a very hot climate with extreme rainfall in monsoon season, i.e., June to September. These drastic changes in the climate severely affect the various activities throughout the coastal area of Karnataka. Understanding the variability of climate in the region is essential. In this study, the variation in the climate for a period of 1984–2017 is observed and investigated and changes in the trend in the grid points can be noticed. Mann–Kendall trend test is applied for the precipitation to find trend patterns, and the magnitude of the trend is determined by Sen’s slope estimator. Increase in trend was found in the grid point 3 and grid point 4. © Springer Nature Singapore Pte Ltd 2021.
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    Free vibration studies of box type laterite masonry structures
    (2012) Unnikrishnan, S.; Narasimhan, M.C.; Venkataramana, K.
    Box-type laterite masonry structures are widely seen in south-west coastal areas of India. Not many studies are available in the literature on the dynamic response of such structures. Free vibration analysis of box-type laterite masonry structures has been attempted in this study, as a preliminary to a detailed dynamic analysis. Finite element analysis has been conducted to And the natural frequencies and corresponding mode shapes of box-type laterite masonry buildings. Results of detailed parametric studies conducted to find the effect of various parameters like modulus of elasticity of laterite masonry, provision of a lintel band or a roof slab, openings in long walls and aspect ratio on the natural frequencies and their mode shapes of box-type laterite masonry buildings are presented and discussed in this paper.
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    Quantifying aquifer properties and freshwater resource in coastal barriers: A hydrogeophysical approach applied at Sasihithlu (Karnataka state, India)
    (2012) Vouillamoz, J.-M.; Hoareau, J.; Grammare, M.; Caron, D.; Nandagiri, L.; Legchenko, A.
    Many human communities living in coastal areas in Africa and Asia rely on thin freshwater lenses for their domestic supply. Population growth together with change in rainfall patterns and sea level will probably impact these vulnerable groundwater resources. Spatial knowledge of the aquifer properties and creation of a groundwater model are required for achieving a sustainable management of the resource. This paper presents a ready-to-use methodology for estimating the key aquifer properties and the freshwater resource based on the joint use of two non-invasive geophysical tools together with common hydrological measurements.

    We applied the proposed methodology in an unconfined aquifer of a coastal sandy barrier in South-Western India. We jointly used magnetic resonance and transient electromagnetic soundings and we monitored rainfall, groundwater level and groundwater electrical conductivity. The combined interpretation of geophysical and hydrological results allowed estimating the aquifer properties and mapping the freshwater lens. Depending on the location and season, we estimate the freshwater reserve to range between 400 and 700 L m??'2 of surface area (A± 50%). We also estimate the recharge using time lapse geophysical measurements with hydrological monitoring. After a rainy event close to 100% of the rain is reaching the water table, but the net recharge at the end of the monsoon is less than 10% of the rain. Thus, we conclude that a change in rainfall patterns will probably not impact the groundwater resource since most of the rain water recharging the aquifer is flowing towards the sea and the river. However, a change in sea level will impact both the groundwater reserve and net recharge. © Author(s) 2012.
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    Development of resilient breakwater against earthquake and Tsunami
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2019) Chaudhary, B.; Hazarika, H.; Murakami, A.; Fujisawa, K.
    The coastal areas in Japan suffered devastating damage due to the great East Japan earthquake and tsunami in 2011. Breakwaters collapsed mainly because of foundation failures during the earthquake and tsunami. Due to the breakwater failures, the tsunami entered the coastal zones and imposed deep devastation. This study focused on the development of reinforcing countermeasures for a breakwater foundation that can produce a resilient breakwater against earthquakes and tsunamis, such as foundations reinforced with sheet piles and gabions. Physical model tests were carried out for scaled-down breakwater models to examine the performance of the reinforcing countermeasures under an earthquake and tsunami. During the tests, the developed reinforced model was found to be effective in mitigating the damage of the breakwater created by the earthquake and tsunami. Numerical simulations were performed to further clarify the mechanism. © 2018 American Society of Civil Engineers.
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    Underwater wireless optical communications based reconfigurable UOWSN for monitoring and discovering continental margin ore deposits
    (Optica Publishing Group (formerly OSA), 2022) Bhargava Kumar, B.K.; Naik, R.P.; Krishnan, P.; Majumdar, A.K.
    Changes in the environment, such as landslides, tsunamis, rising or falling sea levels in coastal oceans, and neighboring land surfaces, significantly impact the structure of the ocean and human life. These natural climate-change processes have unanticipated and deadly consequences for coastal areas. The continental margin part of the ocean has recently attracted the most attention because of the mineral sources and human activities such as exploration, navigation, recreation, and fishing. The continental margin stretches fromthe coastal mountains and plains to continental shelf, slope, and rise, where terrestrial and maritime means meet. In this paper, we propose a reconfigurable underwater optical wireless sensor network (UOWSN) based on underwater wireless optical communication (UWOC) to monitor and discover continental margin ore deposits. In this proposed system, a transceiver on the underwater wireless autonomous vehicle moving around the different regions of the continental margin collects information and transmits it to the seashore control station once it reaches the ocean surface. We investigated the outage probability and average bit error rate of the proposed system at the continental margin and used coding techniques to mitigate the effects of high turbulence in the continental shelf region. © 2022 Optica Publishing Group.