Browsing by Author "Harel Thomas"

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Doping impacts of La2O3 on physical, structural, optical and radiation shielding properties of (30-x)BaCO3-30TiO2-40SiO2-xLa2O3 (0 ≤ x ≤ 6) glasses for optoelectronic applications
(Institute of Physics, 2023) Rajat Kumar Mishra; Savita Kumari; Shweta; Prince Sen; Sarvesh Kumar Avinashi; Zaireen Fatima; Harel Thomas; Manasi Ghosh; Krishna Kishor Dey; Chandkiram Gautam
Herein, synthesis of novel barium silicate glasses doped with La2O3 in the system (30-x)BaCO3-30TiO2-40SiO2-xLa2O3, BTSL (0 ≤ x ≤ 6) via fast melt-quenching technique was carried out. Further, to confirm the amorphous behaviour of prepared glass samples, x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were carried out. The density of all prepared glasses was determined using Archimedes’ principle and found to be in an increasing manner. To investigate the doping influence of La2O3 on the glasses, few more physical properties like molar volume (Vm), polaron radius (rp), and field strength (Fs) were also studied and found to be increased due to incorporation of La2O3 into BTSL glassy system. Moreover, to explore the structural, functional, and bonding mechanism of the glasses, FTIR, Raman and 29Si-MAS-ssNMR spectroscopies were performed. Further, to investigate the numerous optical parameters, UV-visible spectroscopy was executed, and energy band gaps were found in the decreasing manner as increasing the La2O3 concentrations. Additionally, to study the optoelectronic properties, refractive indices (η) and optical dielectric constant (ϵ) were determined and revealed the increasing behaviour and found suitable material for optoelectronic devices. Furthermore, the radiation shielding parameters, mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), etc were determined using Phy-X/PSD software and these parameters are increased owing to the doping of La2O3. Among all fabricated glasses, (30-x)BaCO3-30TiO2−40SiO2−6La2O3, BTS6L glass exhibited outstanding optical and radiation attenuation properties; can be tailored for the fabrication of optoelectronic and radiation protection devices. © 2023 IOP Publishing Ltd.
Evolution of the Permo-Triassic Satpura Gondwana Basin, Madhya Pradesh, India: Insights from geochemical provenance and palaeoclimate of the siliciclastic sediments
(John Wiley and Sons Ltd, 2023) Yumlembam Priyananda Singh; Oinam Kingson; Kongrailatpam Milankumar Sharma; Prosenjit Ghosh; Rajeev Patnaik; Raghavendra Prasad Tiwari; Jitendra Kumar Pattanaik; Pankaj Kumar; Harel Thomas; Ningthoujam Premjit Singh; Nongmaithem Amardas Singh
Geochemical study in the siliciclastic sediments of a basin provides an understanding of palaeoclimate, provenance and subsequently, it can be used to reconstruct the palaeo-tectonics and evolution of the basin. Sedimentation in the Gondwana basins, worldwide, generally provides a record of climatic fluctuations and evidences of the Permo-Triassic mass extinction. In spite of its global importance, our knowledge about the nature of sedimentation, basin development and conceptual regional tectonic model in the Satpura Basin, one of the Gondwana basins of India is limited. Major and trace element concentrations of the mudstones from the Denwa Formation along with the existing geochemical data of other formations are studied here for establishing a comprehensive idea about the palaeoclimate, tectonic settings, provenance and basin evolution. The composition of the sediments in the lowermost Talchir Formation revealed cold and dry climatic conditions at the sources, whereas the sources of the sediments for the overlying formations have experienced warm, humid and semiarid climates. The contributions of the mafic rock-derived sediments are relatively higher in the Talchir, Barakar and Motur formations compared to the overlying formations. Approximately 60% of the sediments in the overlying Bijori, Pachmarhi and Denwa formations were derived from the felsic volcanic rocks and granites of the Sausar Mobile Belt and Betul-Chindwara Mobile Belt (BCMB) with minor inputs from mafic volcanic rocks of the BCMB. Furthermore, the sediments of the Talchir Formation were derived from the BCMB when they became tectonically active, whereas the sediments in the younger formations have been derived from a passive tectonic setting. © 2022 John Wiley & Sons Ltd.
Geochemistry of the siliciclastic sediments from the Raniganj Gondwana basin, West Bengal, India, and its geological implications
(Science Press, 2025) Yumlembam Priyananda Singh; Oinam Kingson; K. Milankumar Sharma; Raghavendra Prasad Tiwari; Rajeev Patnaik; Prosenjit Ghosh; Anupam Sharma; Jitendra K. Pattanaik; Pankaj Kumar; Harel Thomas; Ningthoujam Premjit Singh; Prem Chand Kisku; Nongmaithem Amardas Singh
Elemental concentrations of the siliciclastic sediments from a sedimentary basin provide clues on paleo-weathering, paleoclimate, provenance, and tectonic setting of the basin. Records for Permo–Triassic mass extinction and climatic fluctuations are commonly traced from the sediments in the Gondwana basins. Nevertheless, our understanding on sedimentation, provenance, and regional tectonics of the Raniganj Basin, a Gondwana basin in the eastern India is poor. Minerals including clay particles and major and trace element concentrations of the siliciclastic sediments from different formations of the Raniganj Basin have been studied to establish the paleo-weathering, paleoclimate, provenance, and tectonic settings of the basin. This study suggests that the Talchir Formation experienced cold and dry climatic conditions at the sediment source area, while the Barakar, Raniganj, and Panchet formations had prevailing semiarid climates. The sources of the siliciclastic sediments are from the felsic rocks of the Chotanagpur Granite Gneissic Complex (CGGC). Further, the geochemical results suggest a rift-like (passive) tectonic setting for the Raniganj Basin, while few samples represent the collision tectonic setting of the basement CGGC, formed due to collision of major Indian blocks during the Paleo-Neoproterozoic time. © The Author(s), under exclusive licence to Science Press and Institute of Geochemistry, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2025.