Nearshore sediment dynamics of Kavaratti Island, Lakshadweep archipelago using integrated modelling system

845-857The Kavaratti Island of Lakshadweep archipelago exhibits high coastal erosion and shoreline changes due to the anthropogenic stresses on the island morphology. This study focuses on the shoreline analysis using Digital Shoreline Analysis System model and nearshore sediment dynamics using an integrated modeling system with high resolution bathymetry of ~15 m. The sediment load and bed level change were estimated using the sediment transport model through the feedback mechanism of flow and wave forces. The model simulations were performed during winter, pre-monsoon, monsoon and post-monsoon seasons for the year 2015 and calibrated using the field observation datasets. Shoreline change studies indicate the coastal erosion of about 83.43 % and accretion of about 16.55 % along the island coast. The study signifies the erosion around the fishing jetty and accretion at the western (Katchery) jetty due to wave induced currents and tidal influx. The scouring effect due to the presence of tetrapods along the island coast is observed between 0.02 and 0.18 m

A numerical study of coastal inundation and its validation for Thane cyclone in the Bay of Bengal

The numerical modeling of coastal inundation from severe cyclones is a challenging area for coastal hazard mapping, emergency planning and evacuation measures. There is a need for realistic estimate of onshore coastal inundation by the operational weather centers for precise warnings to minimize loss of life and property. At present, there is no modeling effort to evaluate the extent of coastal inundation for any coastal state in India. The operational center disseminates information only on peak surge and its location just before cyclone landfall, with no prior information about onshore inundation. To bridge this gap, the present study applies the state-of-art ADCIRC hydrodynamic model to evaluate peak surge and onshore inundation along coastal Tamil Nadu for the December 2011 Thane cyclone event. Post-storm analysis and field reconnaissance survey report from IMD and ICMAM were available for the Thane cyclone to skill assess model computation. The model that computed peak surge and onshore inundation is in good concurrence with field measurements. The study signifies that near-shore beach slope has a direct bearing on onshore inundation, and its importance in numerical modeling is highlighted. This study being first of its kind for Indian coast, emphasized that coastal inundation modeling should form an integral part in a storm surge prediction system for operational needs

Performance and validation of a coupled parallel ADCIRC-SWAN model for THANE cyclone in the Bay of Bengal

An accurate prediction of near-shore sea-state is imperative during extreme events such as cyclones required in an operational centre. The mutual interaction between physical processes such as tides, waves and currents determine the physical environment for any coastal region, and hence the need of a parallelized coupled wave and hydrodynamic model. The present study is an application of various state-of-art models such as WRF, WAM, SWAN and ADCIRC used to couple and simulate a severe cyclonic storm Thane that developed in the Bay of Bengal during December 2011. The coupled model (ADCIRC-SWAN) was run in a parallel mode on a flexible unstructured mesh. Thane had its landfall on 30 December, 2011 between Cuddalore and Pondicherry where in-situ observations were available to validate model performance. Comprehensive experiment on the impact of meteorological forcing parameters with two forecasted tracks derived from WRF model, and JTWC best track on the overall performance of coupled model was assessed. Further an extensive validation experiment was performed for significant wave heights and surface currents during Thane event. The significant wave heights measured along satellite tracks by three satellites viz; ENVISAT, JASON-1 and JASON-2, as well in-situ near-shore buoy observation off Pondicherry was used for comparison with model results. In addition, qualitative validation was performed for model computed currents with HF Radar Observation off Cuddalore during Thane event. The importance of WRF atmospheric model during cyclones and its robustness in the coupled model performance is highlighted. This study signifies the importance of coupled parallel ADCIRC-SWAN model for operational needs during extreme events in the North Indian Ocean

Buckling and free vibrations behaviour through differential quadrature method for foamed composites

The current work focuses on predicting the buckling and free vibration frequencies (fn) of cenosphere reinforced epoxy based syntactic foam beam under varying loads. Critical buckling loads (Ncr) and fn are predicted using the differential quadrature method (DQM). Ncr and fn have been calculated for beams of varying cenosphere volume fractions subjected to axial load under clamped-clamped (CC), clamped-simply (CS), simply-simply (SS), and clamped-free (CF) boundary conditions (BC′s). Upon increasing the cenosphere volume fraction, Ncr and fn of syntactic foam composites increases. These numerical outcomes are compared with the theoretical values evaluated through the Euler-Bernoulli hypothesis and further compared with experimental outcomes. Results are observed to be in precise agreement. The results of the DQM numerical analysis are given out for the different BC′s, aspect ratios, cenosphere volume fractions, and varying loads. It is perceived that depending on the BC′s, the type of axial varying loads and aspect ratios has a substantial effect on the Ncr and fn behaviour of the syntactic foam beams. A comparative study of the obtained results showed that the beam subjected to parabolic load under CC boundary conditions exhibited a higher buckling load. © 2023 The Author

A New UPLC Method Development and Validation for Simultaneous Estimation of Netiputant and Palonosetron Using Bulk and Pharmaceutical Dosage Form Using UPLC

A simple and selective LC method is described for the determination of Netupitant and Palonosetron in tablet dosage forms. Chromatographic separation was achieved on a Inertsil ODS (C18) RP Column (250mm x 4.6 mm. 5µm) column using mobile phase consisting of a 55 volumes of mixed phosphate buffer and 45 volumes of acetonitrile were prepared with detection of 253nm. Linearity was observed in the range 25-125 µg/ml for Netupitant (r 2 =0.995) and 50-150 µg /ml for Palonosetron (r 2 =0.999) for the amount of drugs estimated by the proposed methods was in good agreement with the label claim. The proposed methods were validated. The accuracy of the methods was assessed by recovery studies at three different levels. Recovery experiments indicated the absence of interference from commonly encountered pharmaceutical additives. The method was found to be precise as indicated by the repeatability analysis, showing %RSD less than 2. All statistical data proves validity of the methods and can be used for routine analysis of pharmaceutical dosage form