National Institute of Technology, Karnataka

About: National Institute of Technology, Karnataka is a education organization based out in Mangalore, Karnataka, India. It is known for research contribution in the topics: Computer science & Corrosion. The organization has 5017 authors who have published 7057 publications receiving 70367 citations.

Selective colorimetric chemosensor for the detection of Hg2+ and arsenite ions using Isatin based Schiff's bases; DFT Studies and Applications in test strips

Abstract: Three isatin appended Schiff's base chemosensors (CS1-CS3) were synthesized and characterized by FT-IR, 1H-NMR, 13 C-N MR, and LC–MS. The sensing ability of the synthesized chemosensors towards Hg2+ and AsO2− ions was established through colorimetric / UV–vis techniques and achieved detection limit at ppm levels. All chemosensors CS1-CS3 exhibited rapid colorimetric / UV–vis response with Hg2+, also, CS1 and CS3 displayed dual-ion selectivity towards AsO2− (colour changes orange to aqua-blue) and Hg2+ (from orange to colorless). The binding properties and detection limit has been examined through the UV–vis instrument. The mechanism of binding was investigated using various analytical techniques like FT-IR, UV–vis, mass and 1H-NMR titration experiments. The experimental results were supported by theoretical DFT study. The developed colorimetric chemo-sensors showed a good binding affinity towards metal ions and exhibited good linearity (R2 ≈ >0.99). Further, the developed sensors were used for test strips application to detect the Hg2+, AsO2− ions and achieved naked-eye detection at ppm levels. Hence, CS1-CS3 sensors find its practical application in efficient detection of toxic metals like Hg2+ and AsO2−.

Investigation of Microstructure and Mechanical Properties of ECAP-Processed AM Series Magnesium Alloy

Abstract: Magnesium alloy Mg-Al-Mn (AM70) was processed by equal channel angular pressing (ECAP) at 275 °C for up to 4 passes in order to produce ultrafine-grained microstructure and improve its mechanical properties. ECAP-processed samples were characterized for microstructural analysis using optical microscopy, scanning electron microscopy, and transmission electron microscopy. Microstructural analysis showed that, with an increase in the number of ECAP passes, grains refined and grain size reduced from an average of 45 to 1 µm. Electron backscatter diffraction analysis showed the transition from low angle grain boundaries to high angle grain boundaries in ECAP 4 pass sample as compared to as-cast sample. The strength and hardness values an showed increasing trend for the initial 2 passes of ECAP processing and then started decreasing with further increase in the number of ECAP passes, even though the grain size continued to decrease in all the successive ECAP passes. However, the strength and hardness values still remained quite high when compared to the initial condition. This behavior was found to be correlated with texture modification in the material as a result of ECAP processing.

Spatial variation in drainage characteristics and geomorphic instantaneous unit hydrograph (GIUH); implications for watershed management—A case study of the Varada River basin, Northern Karnataka

Abstract: Geomorphological characteristics can be treated as signatures of hydrological responses. Geomorphologic instantaneous unit hydrograph (GIUH) is of utmost use in planning watershed management programs on a broad scale in absence of hydrologic data. Fifth order basins from different agroclimatic zones in the Varada River basin were selected to understand the spatial variation in drainage characteristics. These sub-basins show significant differences in their morphometric properties such as basin area, drainage density, bifurcation ratio, circularity ratio, constant of channel maintenance etc. These differences reflect variation in the hydrological process and geomorphologic instantaneous unit hydrograph (GIUH) of different sub-basins and can be used to understand watershed management aspects. Fifth order sub-basin in the Southern Transition agroclimatic zone is potential for artificial recharge programs. Sub-basins in the Hilly non-forest zone on the north are ideal for surface water storage like tank development program while Forested Hilly zone on the north are environmentally sensitive and prone to erosion.