Browsing by Author "Kumar, Hemant"

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    Al-doped ZnO based long range optical fibre sensor for efficient low refractive index detection
    (Springer, 2023) Kumar, Hemant; Kumar, Raj; Ramani, Umang; Singh, Bipin K.; Pandey, Praveen C.
    In this article, a simulation of surface plasmon resonance (SPR) based Al-doped ZnO (AZO) coated long-range low refractive index detections in infrared range sensor by the finite element method is presented. Plasmonic material Al-doped ZnO is used for SPR conditions in the desired range. The effects of AZO layer thickness on resonance wavelength, confinement loss, and sensitivity of the proposed sensor are examined for different analyte refractive indices. We have optimized coated AZO layer thickness of 90�nm and width of 124.70��m in our work. The proposed infrared sensor has achieved refractive index sensitivity 2000�16,000�nm/RIU, and the resolution 5.00�10-5-6.25�10-6RIU for the analyte�s refractive index range from 1.23 to 1.37. The proposed sensor may be utilized for detecting low refractive index organic chemicals, biomedical, and liquid foods and may also be used in other sensing applications. � 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
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    Geochemistry of recent sediments of the Kurheri basin, Son River, Madhya Pradesh, Central India: implications for source area weathering, sediment provenance, maturity, and sorting
    (Springer Science and Business Media Deutschland GmbH, 2023) Paul, Abdul Qayoom; Dar, Shamim A.; Singh, B.P.; Kumar, Hemant; Ahmad, Mansoor
    The geochemical signatures of recent stream sediments in the study area revealed an old recycled sedimentary source and weak to moderate chemical weathering. The sediments exhibit a positive correlation of large ion lithophile elements (Ba, Sr, and Rb), transition trace elements (Co, Cr, Cu, Ni, Sc, and V), and REE with Al2O3 and associated immobile oxides, indicating affinity with phyllosilicate sedimentary rocks of Semri Group of Vindhyan basin. The La�Th�Sc and Th�Sc�Zr/10 ternary plots show mixed sediment sources of clays, silts, and sands. Positive correlations of LREE with Th, Zr, Al2O3, and TiO2 and negative correlations with Y and P2O5 suggests the cumulative influence of Ti-bearing minerals and clay minerals. The high Zr/Sc ratio (mean 30.8), strong LREE/HREE enrichment (mean 8.1), prominent negative Eu anomalies (mean 0.57) and flat HREE suggest input from the recycled sedimentary source. The mean chemical index of alteration (69.17), plagioclase index of alteration (74.94), chemical index of weathering (93.08), and ACNK indicate weak to moderate weathering with the presence of minor K-feldspar mixed in illite�dominated mud. This is also supported by a high Rb/Sr ratio (mean 1.09) and K/Rb ratio (0.018). A higher K/Al than Na/Al ratio points to higher illite content. The presence of illite, minor feldspar, and less SiO2/Al2O3 ratio (mean 4.98) suggests low textural and compositional maturity, attributed to the mixing of sediments by significant physical weathering. The positive correlation between Th/Sc (mean 0.6) and Zr/Sc (30.8) indicates less fractionation, low to moderate hydraulic sorting, and sufficient sediment recycling in Kurheri sediments. � 2023, Geologische Vereinigung e.V. (GV).
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    Investigations on the Highly Sensitive Metal-Coated Broad Range D-Shaped Optical Fiber Refractive Index Sensor
    (Springer, 2021) Kumar, Hemant; Ramani, Umang; Singh, Bipin K.; Pandey, Praveen C.
    In this paper, we present a detailed study on surface plasmon resonance (SPR)-based D-shaped single-mode optical fiber sensor for the range of refractive index (RI) 1.33�1.42 sensing using the finite element method (FEM). Gold (Au), silver (Ag), and copper (Cu) metal layers have used separately to investigate the performance of proposed sensor employed with SPR conditions. Average and maximum sensitivity of the sensor increases with the thicknesses of the metal layer. We observe the higher sensitivity for the Au layer in comparison to Ag and Cu layers. Sensor with Au layer with 50�nm thickness shows the average sensitivity of 5855�nm/RIU with maximum sensitivity of 15,200�nm/RIU and resolution 1.780 � 10?5 RIU. The figure of merit (FOM) has also investigated for such sensor. The sensing performance of the sensor sequentially decreases with Ag and Cu layers. The proposed optical fiber sensors with high sensing performance can be utilized as RI sensors for different chemical and biological sensing. � 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
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    Virtual screening and molecular simulation study of natural products database for lead identification of novel coronavirus main protease inhibitors
    (Taylor and Francis Ltd., 2022) Tripathi, Nancy; Goel, Bharat; Bhardwaj, Nivedita; Sahu, Bharat; Kumar, Hemant; Jain, Shreyans K.
    3CL like protease (3CLpro or Mpro) is one of the main proteases of 2019-nCoV. The 3CLpro is a nonstructural protein of SARS-CoV and has an essential role in viral replication and transcription, thus, could be a potential target for anti-SARS drug development. The present study employed ligand- and structure-based approaches to identify the potent inhibitors of 2019-nCoV protease. The e-pharmacophore developed from 3CLpro-1 yielded virtual hits, that were subjected through drug likeliness and PAINS filters to remove interfering compounds. Further comprehensive docking studies, free energy calculations and ADMET studies resulted in two virtual leads- MolPort-000-410-348 and MolPort-002-530-156. The compounds MolPort-000-410-348 and MolPort-002-530-156 displayed good docking score of ?12.09 and ?13.38 Kcal/mol and free binding energy of ?63.34 � 2.03 and ?61.52 � 2.24 Kcal/mol, respectively. The compounds also exhibited satisfactory predicted ADMET profile and were subjected to molecular dynamic (MD) studies. The MD simulation produced stable complexes of these ligands with 3CLpro protein and ligand RMSD in acceptable limits. Communicated by Ramaswamy H. Sarma. � 2020 Informa UK Limited, trading as Taylor & Francis Group.