Faculty Publications
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Item Characterization of PtIV-containing polyoxometalates by high-resolution solid-state 195Pt and 51V NMR spectroscopy(Royal Society of Chemistry, 2016) Dugar, S.; Izarova, N.V.; Mal, S.S.; Fu, R.; Joo, H.-C.; Lee, U.; Dalal, N.S.; Pope, M.T.; Jameson, G.B.; Kortz, U.We report on the feasibility of applying high-resolution solid-state 195Pt MAS NMR spectroscopy for several PtIV-containing polyoxotungstates, and of 195Pt as well as 51V for a PtIV-containing polyoxovanadate. This method is particularly useful for polyanions which are unstable in solution and/or poorly soluble, as well as for systems exhibiting crystallographic disorder of Pt and W sites. We also report solution 195Pt and 183W NMR spectra of hexatungstoplatinate(iv) [H3PtW6O24]5- for the first time. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016.Item Bio-corrosion impacts on mechanical integrity of ZM21 Mg for orthopaedic implant application processed by equal channel angular pressing(Springer, 2021) Sekar, P.; Nyahale, M.B.; Naik, G.M.; Narendranath, N.; Prabhu, A.; Rekha, P.D.The mechanical integrity of rolled ZM21 Mg was improved by equal channel angular pressing (ECAP) to function as a potential biodegradable bone screw implant. Electron backscattered diffraction (EBSD) revealed deformed grains of 45 µm observed in rolled ZM21 Mg. They were transformed to equiaxed fine grains of 5.4 µm after 4th pass ECAP. The yield strength of rolled and ECAPed ZM21 Mg alloys were comparable. In contrast, 4th pass ZM21 Mg exhibited relatively higher elongation when compared to rolled sample. The mechanical properties of rolled and ECAPed ZM21 Mg were dependant on both grain refinement and crystallographic texture. The rolled and 4th pass ECAPed tensile samples exhibited nonlinear deterioration of mechanical properties when tested after 7, 14, 21 and 28 days immersion in Hank’s solution. The evaluation signifies that regardless their processing condition, ZM21 Mg alloys are suitable for surgical areas that requires high mechanical strength. In addition, the 4th pass ECAP samples were viable to MG-63 cells proving themselves to be promising candidates for future in vivo studies. [Figure not available: see fulltext.] © 2021, The Author(s).Item Investigation of microstructure and mechanical properties of microwave consolidated TiMgSr alloy prepared by high energy ball milling(Elsevier B.V., 2022) Pradeep, N.B.; Rajath Hegde, M.M.R.; Rajendrachari, S.; Surendranathan, A.O.The nanostructured TiMgSr (at.% 70:10:20) was synthesized by ball milling process followed by cold compaction and microwave sintering. XRD results after 30 h milling showed crystallite size of ⁓41 nm with a lattice strain of 2.5% and evolution of solid solutions like Mg5.2Sr, MgTiO3. The phases formed from 30 h mechanically alloyed powder are in good agreement with TEM SADP results. Consolidation using microwave sintering resulted in the retention of nanostructure with crystallite size of 78 nm and lattice strain of 1.2%. Densification study results in porosity of 19.8% with almost 20% density reduction compared to CP-Ti. The obtained porosity has promoted density reduction along with low elastic modulus that could be biocompatible with human bone tissue. Nanoindentation test results showed a low modulus of 36 ± 7 GPa with a hardness of 1.8 ± 0.8 GPa. These results are comparable with those Ti alloys produced by various techniques and found to be relatively superior for biomedical applications. © 2022Item Molecular surface-dependent light harvesting and photo charge separation in plant-derived carbon quantum dots for visible-light-driven OH radical generation for remediation of aromatic hydrocarbon pollutants and real wastewater(Academic Press Inc., 2024) Meena, S.; Sethi, M.; Saini, S.; Kumar, K.; Saini, P.; Meena, S.; Kashyap, S.; Yadav, M.; Meena, M.L.; Dandia, A.; Nirmal, N.K.; Parewa, V.Despite the growing emphasis on eco-friendly nanomaterials as energy harvesters, scientists are actively searching for metal-free photocatalysts to be used in environmental remediation strategies. Developing renewable resource-based carbon quantum dots (CQDs) as the sole photocatalyst to harvest visible light for efficient pollutant degradation is crucial yet challenging, particularly for addressing the escalating issue of water deterioration. Moreover, the photocatalytic decomposition of H2O2 under visible light irradiation remains an arduous task. Based on this, we designed two types of CQDs, C-CQDs (carboxylic-rich) and A-CQDs (amine-rich) with distinct molecular surfaces. Owing to the higher amount of upward band bending induced by amine-rich molecular surface, A-CQDs efficiently harvest the visible light and prevent recombination kinetics resulting in prolonged lifetimes (25 ps), and augmented charge carrier density (35.7 × 1018) of photoexcited charge carriers. A-CQDs enabled rapid visible-light-driven photolysis of H2O2 (k = 0.058 min−1) and produced higher quantity of •OH radicals (0.158 μmol/sec) for the mineralization of petroleum waste, BETX (i.e. Benzene, Ethylbenzene, Toluene and Xylene) (k = 0.017–0.026 min−1) and real textile wastewater (k = 0.026 min−1). To assess comparative toxicities of both remediated and non-remediated real wastewater samples in a time and dose depended manner, Drosophila melanogaster was used as a model organism. The findings unequivocally demonstrate the potential of remediated wastewater for watering urban forestry. © 2024 Elsevier Inc.