Highly selective, rapid and simple colorimetric detection of Fe3+ in fortified foods by L-Cysteine modified AuNP
N Borah, AJ Kalita, AK Guha, MR Das, C TamulyMicrochemical Journal , vol: 179 , 107480, 2022 , 10.1016/j.microc.2022.107480
Abstract:
Phosphoric acid assisted synthesis of fluorescent carbon dots from waste biomass for detection of Cr (VI) in aqueous media
J. Goswami, S. S. Rohman, A. K. Guha, P. Basyach, K. Sonowal, S. P. Borah, L. Saikia, P. HazarikaMaterials Chemistry and Physics , vol: 286 , 126133, 2022 , 10.1016/j.matchemphys.2022.126133
Abstract:
Viability of half‐sandwich complex of heavier group‐14 elements (SiPb) with neutral Be3 ring and its potential application as H2 storage material
A. J. Kalita, P. Dutta, F. Yashmin, R. R. Borah, R. P. Deka, A. K. GuhaInternational Journal of Quantum Chemistry , vol: 122 , e26878, 2022 , 10.1002/qua.26878
Abstract:
Novel thioether Schiff base transition metal complexes: Design, synthesis, characterization, molecular docking, computational, biological and catalytic studies
A. Singh, H. P. Gogoi, P. Barman, A. K. GuhaApplied Organometallic Chemistry , vol: 36 , e6673, 2022 , 10.1002/aoc.6673
Abstract:
Rhodium (I) carbonyl complexes containing amino acid ester ligands: synthesis, reactivity and DFT studies
B. J, Sarmah, J. Nath, A. K. GuhaJournal of Coordination Chemistry , 2022 , 10.1080/00958972.2022.2059358
Abstract:
Condensation Product of 1-Naphthaldehyde and 3-Aminophenol: Fluorescent “on” Probe for Ce3+ and “off” Probe for Dichromate (Cr2O72−)
P. Bordoloi, A. K. Guha, D. K. DasJournal of Fluorescence , vol: 32 , 1189, 2022 , 10.1007/s10895-022-02927-0
Abstract:
Chirally modified cobalt-vanadate grafted on battery waste derived layered reduced graphene oxide for enantioselective photooxidation of 2-naphthol: Asymmetric induction through non-covalent interaction
M. J. Baruah, T. J. Bora, G. Gogoi, N. Hoque, N. K. Gour, S. K. Bhargava, A. K. Guha, J. K. Nath, B. Das, K. K. BaniaJournal of Colloid and Interface Science , vol: 608 , 1526, 2022 , 10.1016/j.jcis.2021.10.091
Abstract:
Aromatic B3 Ring Stabilized Group 2 Dimer, B3-YY-B3 (Y= Be, Mg, Ca)
R. R. Borah, A. J. Kalita, F. Y.asmin, K. Sarmah, R. P. Deka, D. Konwar, A. K. GuhaPolyhedron , vol: 215 , 115681, 2022 , 10.1016/j.poly.2022.115681
Abstract:
Tetrametallic Copper Complex to Nanoscale Copper: Selective and Switchable Dehydrogenation‐Hydrogenation under Light
A. R. Shelte, K. Sarmah, A. K. Guha, S. PratiharChemistry–A European Journal , vol: 28 , e202103383, 2022 , 10.1002/chem.202103383
Abstract:
Planar Pentacoordinate Zinc Group Elements Stabilized by Multicentric Bonds
A. J. Kalita, I. Baruah, K. Sarmah, R. R. Borah, F. Yashmin, A. K. GuhaInorganic chemistry , vol: 61 , 1259, 2022 , 10.1021/acs.inorgchem.1c03426
Abstract:
Efficient hydroxylation of benzene to phenol by H 2 O 2 using Ni-doped CuWO 4 on carbon nitride as a catalyst under solar irradiation and its structure–activity relationship
P. Basyach, A. K. Guha, S. Borthakur, L. Kalita, P. Chetia, K. Sonowal, L. SaikiaJournal of Materials Chemistry A , vol: 10 , 10790, 2022
Abstract:
Highly sensitive and selective colorimetric detection of dual metal ions (Hg 2+ and Sn 2+) in water: an eco-friendly approach
R. Paw, M. Hazarika, P. K. Boruah, A. J. Kalita, A. K. Guha, M. R. Das, C. TamulyRSC advances , vol: 12 , 11345, 2022 , 10.1039/D2RA90034C
Abstract:
Missing Recipe in the Na-B Bond in NaBH3– Cluster
A. J. Kalita, K. Sharma, R. R. Borah, F. Yashmin, L. J. Mazumder, S. K. Purkayastha, K. Das, T. Dutta, A. K. GuhaChemistry Select , vol: 7 , e202201536, 2022 , 10.1002/slct.202201536
Abstract:
Nanofiber induced enhancement of electrical and electrochemical properties in polymer gel electrolytes for application in energy storage devices
S. Borah, A. K. Guha, L. Saikia, M. DekaJournal of Alloys and Compounds , vol: 886 , 161173, 2021 , 10.1016/j.jallcom.2021.161173
Abstract:
σ-Aromaticity in planar pentacoordinate aluminium and gallium clusters
AJ Kalita, K Sarmah, F Yashmin, RR Borah, I Baruah, RP Deka, AK GuhaScientific Reports , vol: 12 , 1, 2022 , 10.1038/s41598-022-14430-4
Abstract:
Insights into the Interaction between Polyphenols and β-Lactoglobulin through Molecular Docking, MD Simulation, and QM/MM Approaches
I Baruah, C Kashyap, AK Guha, G BorgohainACS Omega , 2022 , 10.1021/acsomega.2c00336
Abstract:
Neutral all metal aromatic half-sandwich complexes between alkaline earth and transition metals: an ab initio exploration
Amlan Jyoti Kalita, Prem Prakash Sahu, Ritam Raj Borah, Shahnaz Sultana Rohman, Chayanika Kashyap, Sabnam Swabaka Ullah, Indrani Baruah, Lakhya Jyoti Mazumder, Dimpul Konwar, Ankur Kanti GuhaStructural Chemistry , 2021 , 10.1007/s11224-021-01807-w
Abstract:
Phosphonate functionalized N-heterocyclic carbene Pd (II) complexes as efficient catalysts for Suzuki-Miyaura cross coupling reaction
B Bhattacharyya, AJ Kalita, AK Guha, N GogoiJournal of Organometallic Chemistry , 2021 , 10.1016/j.jorganchem.2021.122067
Abstract:
Fluorescent Sensors for Hg2+ and Cu2+ Based on Condensation Products of 4H-1, 2, 4 Triazole-4-Amine and Carboxylated Benzoic Acids
S Deka, AK Guha, DK DasJournal of Fluorescence , vol: 31 , 1937, 2021
Abstract:
Fe (III) superoxide radicals in halloysite nanotubes for visible-light-assisted benzyl alcohol oxidation and oxidative CC coupling of 2-naphthol
MJ Baruah, TJ Bora, R Dutta, S Roy, AK Guha, KK BaniaMolecular Catalysis , vol: 515 , 111858, 2021
Abstract:
Magnetically separable ZnFe2O4 nanoparticles: A low cost and sustainable catalyst for propargyl amine and NH-triazole synthesis
Roktopol Hazarika, Anirban Garg, Swadhin Chetia, Parmita Phukan, Akshay Kulshrestha, Arvind Kumar, Ankur Bordoloi, Amlan Jyoti Kalita, Ankur Kanti Guha, Diganta SarmaApplied Catalysis A: General , vol: 625 , 118338, 2021
Abstract:
Green synthesis of a vanadium (V) Schiff base complex by grinding method: study on its catalytic and anti-bacterial activity
JJ Boruah, ZS Bhatt, CR Nathani, VJ Bambhaniya, AK Guha, SP DasJournal of Coordination Chemistry , vol: 74 , 2055, 2021
Abstract:
Platin-C Nanoparticles: A Recipe for the Delivery of Curcumin-Cisplatin Combination Chemotherapeutics to Mitochondria
Bhabatosh Banik*, Akash Ashokan, Joshua Choi, Bapurao Surnar and Shanta Dhar*Dalton Transactions , vol: 52 , 3575-3585, 2023 , 10.1039/D2DT03149C
Abstract:
The success story of cisplatin spans over six decades now and yet it continues to be the key player in most chemotherapeutic regimens. Numerous efforts have been made to improve its efficacy, address its shortcomings, and overcome drug resistance. One such strategy is to develop new platinum(IV)-based prodrugs with functionally active ligands to deliver combination therapeutics. This strategy not only enables the drug candidate to access multiple drug targets but also enhances kinetic inertness of platinum complexes and thereby ensures greater accumulation of active drug at the target site. We report the synthesis of Platin-C, a platinum(IV) based cisplatin prodrug tethered to the active component of ancient herbal medicine, curcumin, as one of the axial ligands. This combination complex showed improved chemotherapeutic efficacy in cisplatin resistant A2780/CP-70 cell lines when compared to the individual components. An amine-terminated biodegradable polymer was suitably functionalized with triphenylphosphonium (TPP) cation to obtain mitochondria-directed drug delivery platform. Quantification of Platin-C loading into these NPs using complementary techniques employing curcumin optical properties in high-performance liquid chromatography and platinum-based inductively coupled plasma mass spectrometry evidenced efficacious payload incorporation to result functional activities of both the components. Stability studies for a period of one week indicated that the NPs remain stable enabling substantial loading and controlled release of the prodrug. The targeted nanoparticle (NP) platform was utilized to deliver Platin-C primarily in the mitochondrial network of cancer cells as monitored using confocal microscopy employing the green fluorescence of the curcumin pendant. Our studies showed that amine terminated NPs were relatively less efficient in their ability to target mitochondria despite being positively charged. This re-validated the importance of lipophilic positively charged TPP surface functionalities to successfully target cellular mitochondrion. We validated the capabilities of Platin-C and its mitochondria-targeted nanoparticles towards inflicting mitochondria-directed activity in cisplatin-sensitive and cisplatin-resistant cell lines. Furthermore, our studies also demonstrated the effectiveness of Platin-C incorporated targeted NPs to attenuate cellular inflammatory markers by utilizing curcumin component. This study advances our understandings of cisplatin prodrug approach to combine chemotherapeutic and inflammatory effects in accessing combinatory pathways.
Nanofiber induced enhancement of electrical and electrochemical properties in polymer gel electrolytes for application in energy storage devices
S Borah, AK Guha, L Saikia, M DekaJournal of Alloys and Compounds , vol: 886 , 161173, 2021
Abstract:
Effect of Solvent on Antioxidant Activity of Zanthoxylum oxyphyllum Edgew and its DFT Study
N Chelleng, M Hazarika, AJ Kalita, AK Guha, C Tamuly, vol: 17 , 2021
Abstract:
Modulation of electronic density states of carbon atom via multifaceted Cu doped Co2P particle for robust and efficient electrocatalytic hydrogen evolution reaction in aqueous acidic medium
S Lahkar, S Ahmed, A Bora, K Mohan, SS Rohman, AK Guha, SK DoluiElectrochimica Acta , vol: 455 , 142378, 2023
Abstract:
Synthesis and characterization of GA-AgNPs for highly sensitive and selective dual colorimetric detection of Thiourea and Thiophenol with DFT approach
MN Kaka, N Borah, AK Guha, C TamulyInorganic Chemistry Communications , 110868, 2023
Abstract:
Oriented electric field stabilized beryllium dimer
A K GuhaInternational Journal of Quantum Chemistry , 2023
Abstract:
Inorganic Bergman Cyclization: An Appeal From Theory
C Kashyap, SK Purkayastha, SS Rohman, AK GuhaChemPhysChem , vol: 24 , e202200504, 2023
Abstract:
Planar Octacoordinate Aluminium in Dual Aromatic AlBe4N4− Cluster
Amlan J Kalita, Shahnaz S Rohman, Chayanika Kashyap, Sabnam S Ullah, Indrani Baruah, Lakhya J Mazumder, Dimpul Konwar, Ankur K GuhaJournal of Cluster Science , vol: 34 , 1133, 2023
Abstract:
Robust and promising electrocatalytic oxygen evolution reaction by activated Cu–Co–B amorphous nanosheets
A Kumar, J Muhommad, SK Purkayastha, AK Guha, MR Das, S DekaACS Sustainable Chemistry & Engineering , vol: 11 , 2541, 2023
Abstract:
Inter‐Alkali‐Metal Dative Bond in the MMN3− (M=Alkali Metal) Cluster
A K GuhaChemPhysChem , e202200935, 2023
Abstract:
A theoretical investigation of Zn Zn and Be Be one electron bond
K Sarmah, AJ Kalita, AK GuhaInternational Journal of Quantum Chemistry , vol: 123 , e27006, 2023
Abstract:
Planar pentacoordinate carbon in 16 electron neutral CCu2Be3H4 cluster
AJ Kalita, N Gohain, A Bordoloi, AK GuhaPhysical Chemistry Chemical Physics , 2023
Abstract:
Heterogeneous iron catalyst for C (1)–H functionalization of 2-naphthols with primary aromatic alcohols
Subir Biswas, Dipankar Barman, Gautam Gogoi, Nazimul Hoque, Arpita Devi, Siddhartha K Purkayastha, Ankur Kanti Guha, Jayanta K Nath, Kusum K BaniaOrganic & Biomolecular Chemistry , vol: 21 , 1657, 2023
Abstract:
An in silico study of the selective adsorption and separation of CO 2 from a flue gas mixture (CH 4, CO 2, N 2) by ZnLi 5+ clusters
K Sarmah, SK Purkayastha, AJ Kalita, AK GuhaPhysical Chemistry Chemical Physics , vol: 25 , 5174, 2023
Abstract:
Visible-light driven reaction of CO 2 with alcohols using a Ag/CeO 2 nanocomposite: First photochemical synthesis of linear carbonates under mild conditions
A Malik, S Bhatt, A Soni, PK Khatri, AK Guha, L Saikia, SL JainChemical Communications , vol: 59 , 1313, 2023
Abstract:
Metallic clusters for realizing planar hypercoordinate second-row main group elements and multiple bonded species
Amlan J Kalita, Shahnaz S Rohman, Chayanika Kashyap, Lakhya J Mazumder, Indrani Baruah, Ritam Raj Borah, Farnaz Yashmin, Kangkan Sarmah, Ankur K GuhaElsevier , 2023
Abstract:
Cobalt-Catalyzed Stereospecific C–N/C–O Bond Formation of Oxiranes with Diaziridines
Prabhat K Maharana, Tanumay Sarkar, Subhradeep Kar, Siddhartha K Purkayastha, Ankur K Guha, Tharmalingam PunniyamurthyThe Journal of Organic Chemistry , 2023 , 10.1021/acs.joc.3c00445
Abstract:
Solvent Effect on the Photoinduced Intramolecular Charge-Transfer and Redox Potentials of Three Difuranones
Bidyut Das, Rohan Sharma, Alok Ch Kalita, and Abdul Wahab*The Journal of the Physical Chemistry A , vol: 127 , 4793 - 4800, 2023 , https://doi.org/10.1021/acs.jpca.3c01344
Abstract:
Tuning the Photophysical Properties and Photostability of Bis(naphthobipyrrolylmethene) derived BODIPY via Functionalization
Sahoo, S. S.; Sarma, T.; Kalavala, S. S.; Panda, P. K.Chem. Eur. J. , 2023 , https://doi.org/10.1002/chem.202300942
Abstract:
A series of NIR absorbing and emitting, naphthobipyrrole derived BODIPY dyes are reported. These dyes possess different functional groups viz. −CHO, −CN, −NO2, -Br and Ph at its α,α′-positions. All the derivatives were characterized thoroughly via various spectroscopic means as well as single-crystal X-ray structural analyses. Impacts of functionalization on its photophysical properties as well as photostability were evaluated. For instance, incorporation of the phenyl moieties at the α, α′-positions by Suzuki coupling of the dibromo-derivative 4 with phenyl boronic acid led to substantial bathochromic shift in absorption (762 vs 727 nm) and emission (778 vs 744 nm) relative to the unsubstituted parent dye VI. Theoretical calculations have been performed by ground state optimization to evaluate the electronic transitions which supports experimental observation.
Controlled assembly of a bicyclic porphyrinoid and its 3-dimensional boron difluoride arrays
Zhou, W.; Sarma, T.; Yang, L.; Lei, C.; Sessler, J. LChemical Science , vol: 13 , 7276-7282, 2022 , 10.1039/D2SC01635D
Abstract:
A fully conjugated cryptand-like bicyclic porphyrinoid ligand 4, incorporating three carbazole linkages and four dipyrrin moieties, was prepared via the acid-catalysed condensation of an extended 2,2′-bipyrrole analogue containing a central carbazole moiety and 3,4-diethyl-2,5-diformylpyrrole in 79% isolated yield. This new cryptand-like system acts as an effective ligand and allows for complexation of BF2 (boron difluoride) subunits. Three BODIPY arrays, containing two, three, and four BF2 subunits, namely 4·2BF2, 4·3BF2 and 4·4BF2, could thus be isolated from the reaction of 4 with BF3·Et2O in the presence of triethylamine at 110 °C, albeit in relatively low yield. As prepared, bicycle 4 is characterized by a rigid C2 symmetric structure as inferred from VT NMR spectroscopic analyses. In contrast, the three BODIPY-like arrays produced as the result of BF2 complexation are conformationally flexible and unsymmetric in nature as deduced from similar analyses. All four products, namely 4, 4·2BF2, 4·3BF2 and 4·4BF2, were characterized by means of single crystal X-ray diffraction analyses. Tetramer 4·4BF2 gives rise to a higher extinction coefficient (by 2.5 times) relative to the bis- and tris-BODIPY arrays 4·2BF2 and 4·3BF2. This was taken as evidence for stronger excitonic coupling in the case of 4·4BF2. All three BODIPY-like arrays proved nearly non-fluorescent, as expected given their conformationally mobile nature. The efficiency of reactive oxygen species (ROS) generation was also determined for the new BODIPY arrays of this study.
Kinetic trapping of a cobalt(II) metallocage using a carbazole-containing expanded carbaporphyrinoid ligand
Zhou, W.; Sarma, T.; Su, Y.; Lei, C.*; Sessler, J. L.*Chemical Science , vol: 13 , 692-697, 2022 , 10.1039/d1sc06514a
Abstract:
The meso-unsubstituted expanded porphyrinoid 3, incorporating two carbazole moieties, acts as an effective ligand for Co(II) and permits the isolation and X-ray diffraction-based characterization of a 6![[thin space (1/6-em)]](https://www.rsc.org/images/entities/char_2009.gif)
:3 metal-to-ligand metallocage complex that converts spontaneously to the constituent 2:1 metal-to-ligand metalloring species in chloroform solution. The discrete metalloring is formed directly when the Co(II) complex is crystallized from supersaturated solutions, whereas crystallization from more dilute solutions favors the metallocage. Studies with two other test cations, Pd(II) and Zn(II), revealed exclusive formation of the monomeric metalloring complexes with no evidence of higher order species being formed. Structural, electrochemical and UV-vis-NIR absorption spectral studies provide support for the conclusion that the Pd(II) complex is less distorted and more effectively conjugated than its Co(II) and Zn(II) congeners, an inference further supported by TD-DFT calculations. The findings reported here underscore how expanded porphyrins can support coordination modes, including bimetallic complexes and self-assembled cage structures, that are not necessarily easy to access using more traditional ligand systems.
On the Importance of H‑Bonding Interactions in the Enclathration of Boric Acids in Na(I) Polymers: Experimental and Theoretical Studies
Trishnajyoti Baishya, Kamal K. Dutta, Antonio Frontera, Rosa M. Gomila, Miquel Barceló‑Oliver and Manjit K. BhattacharyyaCrystals , vol: 13 , 895-909, 2023 , 10.3390/cryst13060895
Abstract:
Structure Guiding Supramolecular Assemblies in Metal-Organic Multi-Component Compounds of Mn(II): Experimental and Theoretical Studies
Manjit K. Bhattacharyya, Kamal K. Dutta, Pranay Sharma, Rosa M. Gomila, Miquel Barceló-Oliver and Antonio FronteraCrystals , vol: 13 , 837-851, 2023 , 10.3390/cryst13050837
Abstract:
Cooperative Ternary Assemblies Involving Anion–π/π–π/Anion–π Assemblies and Unconventional Cl•••Cl Interactions in Cu(II) Coordination Compounds: Experimental and Theoretical Studies
Pinku Sarma, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver and Manjit K. BhattacharyyaCrystals , vol: 13 , 517-534, 2023 , 10.3390/cryst13030517
Abstract:
Unconventional Dual Donor-Acceptor Topologies of Aromatic Rings in Amine-Based Polymeric Tetrahedral Zn(II) Compounds Involving Unusual Non-Covalent Contacts: Antiproliferative Evaluation and Theoretical Studies
Pranay Sharma, Rosa M. Gomila, Miquel Barceló-Oliver, Akalesh K. Verma, Diksha Dutta, Antonio Frontera and Manjit K. BhattacharyyaCrystals , vol: 13 , 382-406, 2023 , 10.3390/cryst13030382
Abstract:
Supramolecular Assemblies in Pyridine and Pyrazole based Coordination Compounds of Co(II) and Ni(II): Characterization, Hirshfeld analysis and Theoretical Studies
Trishnajyoti Baishya, Rosa M. Gomila, Miquel Barcelo-Oliver, Diego M. Gil, Manjit K. Bhattacharyya and Antonio FronteraCrystals , vol: 13 , 203-221, 2023 , 10.3390/cryst13020203
Abstract:
Enclathration of Mn(II)(H2O)6 guests and unusual Cu⋯O bonding contacts in supramolecular assemblies of Mn(II) Co-crystal hydrate and Cu(II) Pyridinedicarboxylate: Antiproliferative evaluation and theoretical studies
Trishnajyoti Baishya, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Manjit K. BhattacharyyaPolyhedron , vol: 230 , 116243-116259, 2023 , 10.1016/j.poly.2022.116243
Abstract:
Supramolecular Assemblies involving Energetically Significant Unconventional π(CN)-π and Anion-π(nitrile) Contacts in Zn(II) Coordination Compounds: Antiproliferative Evaluation and Theoretical Studies
Debasish Dutta, Trishnajyoti Baishya, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Manjit K. BhattacharyyaJournal of Molecular Structure , vol: 1274 , 134568-134584, 2023 , 10.1016/j.molstruc.2022.134568
Abstract:
Phenanthroline-based Ni(II) Coordination Compounds involving Unconventional Discrete Fumarate-Water-Nitrate clusters and Energetically Significant Cooperative ternary π-stacked Assemblies: Antiproliferative Evaluation and Theoretical Studies
Hiren Nath, Pranay Sharma, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Jumi Das, Manjit K. BhattacharyyaJournal of Molecular Structure , vol: 1248 , 131424-131340, 2022 , 10.1016/j.molstruc.2021.131424
Abstract:
Charge Assisted Hydrogen Bonded Assemblies and Unconventional O∙∙∙O Dichalcogen Bonding Interactions in Pyrazole-Based Isostructural Ni(II) and Mn(II) Compounds involving Anthraquinone Disulfonate: Antiproliferative Evaluation and Theoretical Studies
Pinku Sarma, Pranay Sharma, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Bandita Baruwa, Manjit K. BhattacharyyaJournal of Molecular Structure , vol: 1250 , 131883-131895, 2022 , 10.1016/j.molstruc.2021.131883
Abstract:
Dicarboxylic Acid-Based Co-Crystals of Pyridine Derivatives Involving Structure Guiding Unconventional Synthons: Experimental and Theoretical Studies
Pranay Sharma, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver and Manjit K. BhattacharyyaCrystals , vol: 12 , 1442-1458, 2022 , 10.3390/cryst12101442
Abstract:
Fumarato and phthalato bridged dinuclear metal–organic Cu(II) and Mn(II) compounds involving infinite fumarate–water assemblies and unusual structure-guiding H-bonded synthons: Antiproliferative evaluation and theoretical studies
Trishnajyoti Baishya, Pranay Sharma, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma and Manjit K. BhattacharyyaNew Journal of Chemistry , vol: 46 , 17817-17833, 2022 , 10.1039/d2nj01860h
Abstract:
Supramolecular Assemblies involving Unconventional Non-Covalent contacts in Pyrazole-Based Coordination Compounds of Co(II) and Cu(II) Pyridinedicarboxylates: Antiproliferative Evaluation and Theoretical Studies
Debasish Dutta, Pranay Sharma, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Trishnajyoti Baishya, Manjit K. BhattacharyyaPolyhedron , vol: 224 , 116025-116037, 2022 , 10.1016/j.poly.2022.116025
Abstract:
Terephthalato and Succinato bridged Mn(II) and Zn(II) Coordination Polymers involving Structure-guiding H-bonded Tetrameric Assemblies: Antiproliferative Evaluation and Theoretical Studies
Pinku Sarma, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Santana Saikia, Manjit K. BhattacharyyaPolyhedron 224 (2022) , vol: 224 , 115982-115994, 2022 , 10.1016/j.poly.2022.115982
Abstract:
Solvent-driven Structural Topologies in Phenanthroline-based Co-crystals of Zn(II) involving Fascinating Infinite Chair-like {[(bzH)4Cl2]2-}n Assemblies and Unconventional Layered Infinite {bz-H2O-Cl}n Anion-Water Clusters: Antiproliferative Evaluation and Theoretical Studies
Debasish Dutta, Pranay Sharma, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Bandita Baruwa, Manjit K. BhattacharyyaNew Journal of Chemistry , vol: 46 , 5638-5652, 2022 , 10.1039/d1nj05234a
Abstract:
Structural Topologies involving Energetically Significant antiparallel π-stacking and Unconventional N(nitrile)∙∙∙π(fumarate) Contacts in Dinuclear Zn(II) and Polymeric Mn(II) Compounds: Antiproliferative Evaluation and Theoretical Studies
Pranay Sharma, Trishnajyoti Baishya, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Jumi Das, Manjit K. BhattacharyyaNew Journal of Chemistry , vol: 46 , 5296-5311, 2022 , 10.1039/d1nj04786
Abstract:
Synthesis, structural topologies and anticancer evaluation of phenanthroline-based 2,6-pyridinedicarboxylato Cu(II) and Ni(II) compounds
Amal Das, Pranay Sharma, Rosa M. Gomila, Antonio Frontera, Akalesh K. Verma, Bipul Sarma and Manjit K. BhattacharyyaPolyhedron , vol: 213 , 115632-115641, 2022 , 10.1016/j.poly.2021.115632
Abstract:
Solvent Driven Structural Topologies involving Unconventional O–H(methanol)⋯π contact and Anti-cooperative HB⋯Anion-π⋯HB assemblies with Unusual Enclathration of dual guest (H2O)4 cores in Mn(II) and Ni(II) Coordination Compounds: Antiproliferative Evaluation and Theoretical Studies
Debasish Dutta, Pranay Sharma, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Munmi Gogoi, Manjit K. BhattacharyyaPolyhedron , vol: 210 , 115503-115516, 2021 , 10.1016/j.poly.2021.115503
Abstract:
Benzoato Bridged Dinuclear Mn(II) and Cu(II) Compounds involving Guest Chlorobenzoates and Dimeric Paddle Wheel Supramolecular Assemblies: Antiproliferative Evaluation and Theoretical Studies
Pranay Sharma, Debasish Dutta, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Manjit K. BhattacharyyaPolyhedron , vol: 208 , 115409-115422, 2021 , 10.1016/j.poly.2021.115409
Abstract:
Unconventional Enclathration of Guest Adipic acid and Energetically Significant Antiparallel π-stacked Ternary Assemblies involving unusual Regium-π(Chelate) Contacts in Phenanthroline-based Ni(II) and Cu(II) Compounds: Antiproliferative Evaluation and Theoretical Studies
Hiren Nath, Pranay Sharma, Rosa M. Gomila, Antonio Frontera, Miquel Barceló-Oliver, Akalesh K. Verma, Kasturi Dutta, Manjit K. BhattacharyyaJournal of Molecular Structure , vol: 1245 , 131038-131049, 2021 , 10.1016/j.molstruc.2021.131038
Abstract:
Supramolecular Assemblies involving Biologically relevant Antiparallel π-stacking and Unconventional Solvent Driven Structural Topology in Maleato and Fumarato bridged Zn(II) Coordination Polymers: Antiproliferative Evaluation and Theoretical Studies
Amal Das, Pranay Sharma, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Ruksana S. Ahmed, Sahid Hussain, Manjit K. BhattacharyyaNew Journal of Chemistry , vol: 45 , 13040-13055, 2021 , 10.1039/D1NJ00619C
Abstract:
Unconventional π-hole and Semi-coordination Regium Bonding interactions directed Supramolecular Assemblies in Pyridinedicarboxylato Bridged Polymeric Cu(II) Compounds: Antiproliferative Evaluation and Theoretical Studies
Pinku Sarma, Pranay Sharma, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Trinayan Barthakur and Manjit K. BhattacharyyaInorganica Chimica Acta , vol: 525 , 120461-120471, 2021 , 10.1016/j.ica.2021.120461
Abstract:
Biologically relevant Unusual Cooperative assemblies and Fascinating Infinite Crown-like Supramolecular Nitrate-Water hosts involving Guest Complex Cations in Bipyridine and Phenanthroline-based Cu(II) Coordination Compounds: Antiproliferative Evaluation and Theoretical studies
Pranay Sharma, Hiren Nath, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Sahid Hussain and Manjit K. BhattacharyyaNew Journal of Chemistry , vol: 45 , 8269-8282, 2021 , 10.1039/d1nj01004b
Abstract:
Biologically relevant and energetically significant cooperative ternary (π–π)2/(π–π)1/(π–π)2 assemblies and fascinating discrete (H2O)21 clusters in isostructural 2,5-pyridine dicarboxylato Co(II) and Zn(II) phenanthroline compounds: antiproliferative evaluation and theoretical studies
Sanjib Chetry, Pranay Sharma, Antonio Frontera, Utpal Saha, Akalesh K. Verma, Bipul Sarma, Paran Jyoti Kalita and Manjit K. BhattacharyyaNew Journal of Chemistry , vol: 45 , 3699-3715, 2021 , 10.1039/d0nj04338a
Abstract:
Energetically Significant Cooperative π-stacked Ternary Assemblies in Ni(II) Phenanthroline Compounds involving Discrete Water Clusters: Anticancer Activities and Theoretical Studies
Pranay Sharma, Pinku Sarma, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma, Bipul Sarma, Trinayan Barthakur, Manjit K. BhattacharyyaJournal of Molecular Structure , vol: 1229 , 129486-129502, 2021 , 10.1016/j.molstruc.2020.129486
Abstract:
Energetically Significant Anti-parallel π-stacking and Unconventional Anion-π interactions in Phenanthroline based Ni(II) and Cu(II) Coordination Compounds: Antiproliferative Evaluation and Theoretical Studies
Pranay Sharma, Pinku Sarma, Antonio Frontera, Sahid Hussain, Akalesh K. Verma, Manjit K. BhattacharyyaInorganica Chimica Acta , vol: 516 , 120082-120093, 2021 , 10.1016/j.ica.2020.120082
Abstract:
Oxalato Bridged Coordination Polymer of Manganese(III) involving Unconventional O∙∙∙π-hole(nitrile) and Antiparallel Nitrile∙∙∙Nitrile Contacts: Antiproliferative Evaluation and Theoretical Studies
Debajit Dutta, Pranay Sharma, Antonio Frontera, Anshuman Gogoi, Akalesh K. Verma, Diksha Dutta, Bipul Sarma, Manjit K. BhattacharyyaNew Journal of Chemistry , vol: 44 , 20021-20037, 2020 , 10.1039/D0NJ03712E.
Abstract:
Energetically Significant Nitrile⋯Nitrile and Unconventional C–H⋯π(nitrile) interactions in Pyridine based Ni(II) and Zn(II) Coordination Compounds: Antiproliferative Evaluation and Theoretical Studies
Amal Das, Pranay Sharma, Antonio Frontera, Akalesh K. Verma, Miquel Barcelo-Oliver, Sahid Hussain, Manjit K. BhattacharyyaJournal of Molecular Structure , vol: 1223 , 129246-129259, 2020 , 10.1016/j.molstruc.2020.129246
Abstract:
Unconventional Formation of a 1D-Chain of H-bonded Water Molecules in Bipyridine-based Supramolecular Hexameric Hosts of Isostructural Coordination Compounds of Co(II) and Zn(II): Antiproliferative Evaluation and Theoretical studies
Sanjib Chetry, Pranay Sharma, Antonio Frontera, Debajit Dutta, Akalesh K. Verma, Manjit K. BhattacharyyaPolyhedron , vol: 191 , 114809-114824, 2020 , 10.1016/j.poly.2020.114809
Abstract:
Adipato Bridged Novel Hexanuclear Cu(II) and Polymeric Co(II) Coordination Compounds involving Cooperative Supramolecular Assemblies and Encapsulated Guest Water Clusters in Square Grid Host: Antiproliferative Evaluation and Theoretical Studies
Hiren Nath, Debajit Dutta, Pranay Sharma, Antonio Frontera, Akalesh K. Verma, Miquel Barceló-Oliver, Mary Devi, Manjit K. BhattacharyyaDalton Transactions , vol: 49 , 9863-9881, 2020 , 10.1039/D0DT0107C
Abstract:
Charge-assisted Hydrogen bonds and nitrile⋯nitrile interactions directed Supramolecular Associations in Cu(II) and Mn(II) Coordination Complexes: Anticancer, Hematotoxicity and Theoretical Studies
Pranay Sharma, Anshuman Gogoi, Akalesh K. Verma, Antonio Frontera, Manjit K. BhattacharyyaNew Journal of Chemistry , vol: 44 , 5473-5488, 2020 , 10.1039/D0NJ00075B
Abstract:
Unconventional DNA-relevant π-stacked hydrogen bonded arrays involving supramolecular guest benzoate dimers and cooperative anion–π/π–π/π–anion contacts in coordination compounds of Co(II) and Zn(II) phenanthroline: experimental and theoretical studies
Manjit K. Bhattacharyya, Utpal Saha, Debajit Dutta, Antonio Frontera, Akalesh K. Verma, Pranay Sharma and Amal DasNew Journal of Chemistry , vol: 44 , 4504-4518, 2020 , 10.1039/c9nj05727g
Abstract:
Energetically significant unconventional O–H•••π Contacts involving Discrete Guest (H2O)8 Clusters in a Fumarato bridged Polymeric Supramolecular Host of Ni(II) Phenanthroline: Antiproliferative Evaluation and Theoretical studies
Hiren Nath, Pranay Sharma, Antonio Frontera, Akalesh K. Verma, Amal Das, Miquel Barceló-Oliver, Manjit K. BhattacharyyaPolyhedron , vol: 176 , 114266-114280, 2020 , 10.1016/j.poly.2019.114266
Abstract:
Energetically Significant antiparallel π-stacking contacts in Co(II), Ni(II) and Cu(II) Coordination Solids of Pyridine-2,6-dicarboxylates: Antiproliferative Evaluation and Theoretical Studies
Manjit K. Bhattacharyya, Debajit Dutta, Swah Mohd. Nashre-ul-Islam, Antonio Frontera, Pranay Sharma, Akalesh K. Verma, Amal DasInorganica Chimica Acta , vol: 501 , 119233-119246, 2020 , 10.1016/j.ica.2019.119233
Abstract:
Antiproliferative Evaluation and Supramolecular Association involving Electrostatically Enhanced π–π interaction in Isostructural Coordination Solids of Mn(II), Co(II) and Zn(II) Chlorobenzoates: Experimental and Theoretical Studies
Swah Mohd. Nashre-ul-Islam, Debajit Dutta, Akalesh K. Verma, Hiren Nath, Antonio Frontera, Pranay Sharma, Manjit K. BhattacharyyaInorganica Chimica Acta , vol: 498 , 119161-119174, 2019 , 10.1016/j.ica.2019.119161
Abstract:
Supramolecular association involving antiparallel CO⋯CO and anion–π contacts in Co(II) and Mn(II) complexes involving 2,5-pyridinedicarboxylate: Anticancer evaluation and theoretical studies
Swah Mohd. Nashre-ul-Islam, Debajit Dutta, Pranay Sharma, Akalesh K. Verma, Antonio Frontera, Manjit K. BhattacharyyaInorganica Chimica Acta , vol: 498 , 119108-119118, 2019 , 10.1016/j.ica.2019.119108
Abstract:
Antiproliferative evaluation and supramolecular association in Mn(II) and Zn(II) bipyridine complexes: Combined experimental and theoretical studies
Manjit K. Bhattacharyya, Anshuman Gogoi, Sanjib Chetry, Debajit Dutta, Akalesh K. Verma, Bipul Sarma, Antonio Franconetti, Antonio FronteraJournal of Inorganic Biochemistry , vol: 200 , 110803-110813, 2019 , 10.1016/j.jinorgbio.2019.110803
Abstract:
Cu(II) and Co(II) coordination solids involving unconventional parallel nitrile(π)–nitrile(π) and energetically significant cooperative hydrogen bonding interactions: Experimental and theoretical studies
Debajit Dutta, Swah. Mohd. Nashre‑ul‑Islam, Utpal Saha, Sanjib Chetry, Ankur K. Guha, Manjit K. BhattacharyyaJournal of Molecular Structure , vol: 1195 , 733-743, 2019 , 10.1016/j.molstruc.2019.06.040
Abstract:
Solvent-driven structural topology involving energetically significant intra- and intermolecular chelate ring contacts and anticancer activities of Cu(II) phenanthroline complexes involving benzoates: experimental and theoretical studies
Manjit K. Bhattacharyya, Utpal Saha, Debajit Dutta, Amal Das, Akalesh K. Verma and Antonio FronteraRSC Advances , vol: 9 , 16339-16356, 2019 , 10.1039/c9ra01181a
Abstract:
Energetically Significant unconventional π‒π Contacts involving Fumarate in a novel Coordination Polymer of Zn(II): in-vitro Anticancer Evaluation and Theoretical Studies
Anshuman Gogoi, Amal Das, Antonio Frontera, Akalesh K. Verma, Manjit K. BhattacharyyaInorganica Chimica Acta , vol: 493 , 1-13, 2019 , 10.1016/j.ica.2019.04.047
Abstract:
Energetically favorable anti-electrostatic hydrogen bonded cationic clusters in Ni(II) 3,5-dimethylpyrazole complexes: anticancer evaluation and theoretical Studies
Anshuman Gogoi, Debajit Dutta, Akalesh K. Verma, Hiren Nath, Antonio Frontera, Ankur K. Guha, Manjit K. BhattacharyyaPolyhedron , vol: 168 , 113-126, 2019 , 10.1016/j.poly.2019.04.043
Abstract:
Supramolecular association in Cu(II) coordination complexes involving energetically significant NO⋯NO π-hole interaction and cooperative π-stacked ternary assembly: Experimental and theoretical studies
Utpal Saha, Debajit Dutta, Hiren Nath, Antonio Franconetti, Antonio Frontera, Manjit K. BhattacharyyaInorganica Chimica Acta , vol: 488 , 159-169, 2019 , 10.1016/j.ica.2019.01.015
Abstract:
Supramolecular association involving nitrile–nitrile interactions in polymeric Mn(II) coordination complexes: A combined experimental and theoretical study
Swah Mohd. Nashre-ul-Islam, Debajit Dutta, Antonio Frontera, Manjit K. BhattacharyyaInorganica Chimica Acta , vol: 487 , 424-432, 2019 , 10.1016/j.ica.2018.12.055
Abstract:
A novel oxalato bridged supramolecular ternary complex of Cu(II) involving energetically significant π-hole interaction: Experimental and theoretical studies
Debajit Dutta, Hiren Nath, Antonio Frontera, Manjit K. BhattacharyyaInorganica Chimica Acta , vol: 487 , 354-361, 2019 , 10.1016/j.ica.2018.12.037
Abstract:
Werner type clathrates involving guest benzoic acid and benzoate in discrete Mn(II) hosts: Experimental and theoretical studies
Utpal Saha, Debajit Dutta, Antonio Bauzá, Antonio Frontera, Bipul Sarma, Manjit K. BhattacharyyaPolyhedron , vol: 159 , 387-399, 2019 , 10.1016/j.poly.2018.11.068
Abstract:
Supramolecular association in Cu(II) and Co(II) coordination complexes of 3,5-dimethylpyrazole: Experimental and theoretical studies
Anshuman Gogoi, Swah Mohd. Nashre-ul-Islam, Antonio Frontera, Manjit K. BhattacharyyaInorganica Chimica Acta , vol: 484 , 133-141, 2019 , 10.1016/j.ica.2018.09.035
Abstract:
An unusual werner type clathrate of Mn(II) benzoate involving energetically significant weak C‒H∙∙∙C contacts: A combined experimental and theoretical study
Swah Mohd. Nashre-ul-Islam, Debajit Dutta, Ankur K. Guha, Manjit K. BhattacharyyaJournal of Molecular Structure , vol: 1175 , 130-138, 2019 , 10.1016/j.molstruc.2018.07.095
Abstract:
A supramolecular dimer of two crystallographically independent Co(II) phthalate bipyridine complexes in one single crystal: Synthesis, crystal structure, and thermal studies
Anshuman Gogoi, Utpal Saha, Debajit Dutta, and Manjit K. BhattacharyyaJournal of structural Chemistry , vol: 60 , 338-345, 2019 , 10.1134/S0022476619020215
Abstract:
Structural Topology of Weak Non-covalent Interactions in a Layered Supramolecular Coordination Solid of Zinc Involving 3-Aminopyridine and Benzoate: Experimental and Theoretical Studies
Debajit Dutta, Swah. Mohd. Nashre‑ul‑Islam, Utpal Saha, Sanjib Chetry, Ankur K. Guha, Manjit K. BhattacharyyaJournal of Chemical Crystallography , vol: 48 , 156-163, 2018 , 10.1007/s10870-018-0723-5
Abstract:
Supramolecular association involving anion–π interactions in Cu(II) coordination solids: Experimental and theoretical studies
Debajit Dutta, Sanjib Chetry, Anshuman Gogoi, Bula Choudhury, Ankur K. Guha , Manjit K. BhattacharyyaPolyhedron , vol: 151 , 381-393, 2018 , 10.1016/j.poly.2018.05.039
Abstract:
Synthesis, crystal structure and application of new cobalt(II) complex [Co(bpy)2NO3](NO3)5H2O as sensitizer dye-sensitized solar cells
N. Goswami P.K. Gogoi, U. Saha, M.K. Bhattacharyya and T.R. ChetiaAsian Journal of Chemistry , vol: 30 , 679-683, 2018 , 10.14233/ajchem.2018.21083
Abstract:
Solid and solution structures and DNA binding properties of [MII (4-CNpy)2(SO4)(H2O)3]•H2O for M = Cu, Co, Ni
Manjit K. Bhattacharyya, P. Grihanjali Devi, Dipak Dasgupta, Sanchay J. Bora and Birinchi K. DasPolyhedron , vol: 35 , 62-68, 2012 , 10.1016/j.poly.2011.12.038
Abstract:
Inverse bilayer structure of mononuclear CoII and NiII complexes of the type M(H2O)3(SO4)(4-CNpy)2
Birinchi K. Das, Sanchay J. Bora, Manjit K. Bhattacharyya and Rama K. BarmanActa Crystallographica Section , vol: B65 , 467-473, 2009 , 10.1107/S0108768109021090
Abstract:
Synthesis and Crystal Structure of [Ni(H2O)2(pdc)(4-CNpy)]•2H2O (pdc = Pyridine-2,6-dicarboxylate, 4-CNpy = 4-cyanopyridne)
Manjit K. Bhattacharyya, Sanchay J. Bora and Birinchi K. DasJournal of Chemical Crystallography , vol: 38 , 195-203, 2008 , 10.1007/s10870-007-9289-3
Abstract:
L-alanine Derived Schiff Base Ligated Vanadium(IV) Complex with Phenanthroline as Co-ligand: Synthesis, Crystal Structure and Hirshfeld Surface Analysis
Tanaya Medhi, Manashi Sahariah & Anshuman GogoiJournal of Chemical Crystallography , 2024 , https://doi.org/10.1007/s10870-024-01006-5
Abstract:
Supramolecular assembly in Cu(II) and Zn(II) compounds with pyridine and anthraquinone-1,5-disulfonate: Experimental and theoretical analysis
Manjit K. Bhattacharyya, Kamal K. Dutta , Subham Banik , Rosa M. Gomila, Miquel Barcelo-Oliver , Antonio FronteraInorganica Chimica Acta , vol: 567 , 122042-122051, 2024 , https://doi.org/10.1016/j.ica.2024.122042
Abstract:
‘Charge Reverse’ Halogen Bonding Contacts in Metal-Organic Multi-Component Compounds: Antiproliferative Evaluation and Theoretical Studies
Subham Banik, Trishnajyoti Baishya, Rosa M. Gomila, Antonio Frontera, Miquel Barcelo-Oliver, Akalesh K. Verma , Jumi Das and Manjit K. BhattacharyyaInorganics , vol: 12 , 111-134, 2024 , https://doi.org/10.3390/inorganics12040111
Abstract:
Photophysics of a Monoannulated Indigo: Intra- and Intermolecular Charge Transfer
Bidyut Das, Smiti Rani Bora, Siddharth Mall Bishen, Hirdyesh Mishra, Dhruba Jyoti Kalita, and Abdul Wahab*The Journal of Physical Chemistry A , vol: 128 , 2565-2573, 2024 , https://doi.org/10.1021/acs.jpca.3c07763
Abstract:
An ensemble-based deep convolution neural network for computer-aided polyps identification from colonoscopy
Pallabi Sharma, Bunil Kumar Balabantaray, Kangkana Bora, Kunio Kasugai, Saurav Mallik, Zhongming ZhaoFrontiers in Genetics [IF: 4.772] , 2022 , https://doi.org/10.3389/fgene.2022.844391
Abstract:
A comparative assessment of deep object detection models for blood smear analysis
Kabyanil Talukdar, Kangkana Bora (Corresponding author), Lipi B. Mahanta, Anup K. DasTissue and Cell, Elsevier [IF:2.466] , vol: 76, , 2022 , https://doi.org/10.1016/j.tice.2022.101761
Abstract:
Study on Enhanced Deep Learning Approaches for Value-Added Identification and Segmentation of Striation Marks in Bullets for Precise Firearm Classification
Subrat K. Dutta, Sudarshan Saikia, Abhilasa Barman, Ritumoni Roy, Kangkana Bora (corresponding author), Lipi B. Mahanta, R SureshApplied Soft Computing, Elsevier [IF 8.263] , vol: 112 , 2022 , https://doi.org/10.1016/j.asoc.2021.107789.
Abstract:
Automated recognition of optical image based potato leaf blight diseases using deep learning
Kulendu Kashyap Chakraborty, Rashmi Mukherjee, Chandan Chakroborty, Kangkana Bora (Corresponding author)Physiological and Molecular Plant Pathology, Elsevier [IF: 2.747] , vol: 117 , 2022 , https://doi.org/10.1016/j.pmpp.2021.101781
Abstract:
Machine Learning Based Approach for Automated Cervical Dysplasia Detection Using Multi-Resolution Transform Domain Features
Kangkana Bora , Lipi B. Mahanta, Kasmika Borah, Genevieve Chyrmang , Barun Barua, Saurav Mallik, Himanish Shekhar Das and Zhongming ZhaoMathematics, MDPI, SCIE indexed [IF:2.592] , 2022 , 10.3390/math10214126
Abstract:
Early detection of Parkinson disease using fusion of discrete wavelet transformation and histograms of oriented gradients
Himanish Shekhar Das, Akalpita Das, Anupal Neog, Saurav Mallik, Kangkana Bora and Zhongming ZhaoMathematics, MDPI, SCIE indexed [IF: 2.5] , 2022 , https://doi.org/10.3390/math10224218
Abstract:
Breast Cancer Detection: Shallow Convolutional Neural Network against Deep Convolutional Neural Networks based approach
Himanish Shekhar Das, Akalpita Das, Anupal Neog, Saurav Mallik, Kangkana Bora and Zhongming ZhaoFrontiers in Genetics [IF:4.772] , 2022
Abstract:
A DWT-based Encoder-Decoder Network for Specularity Segmentation in Colonoscopy Images
Vanshali Sharma, M.K.Bhuyan, Pradip K. Das, Kangkana BoraMultimedia Tools and Application, Springer [IF:2.577] , 2023 , https://doi.org/10.1007/s11042-023-14564-1
Abstract:
ML based PCB Classification with Gabor and Statistical Features
Kangkana Bora, M.K. Bhuyan, Yuji Iwahori, Genevieve Chyrmang, Debajit SarmaInternational Conference on Data Electronics and Computing (ICDEC), NEHU, Shillong , 2022
Abstract:
Computer aided Identification of Loom Types of ethnic textile, the Gamusa, using Texture feaxtures and Random Forest Classififer
Kangkana Bora, Lipi B.Mahanta, C. Chakraborty, Prahlad Borah, Kungnor Rangpi, Barun Barua, Bishnu Sharma, R. MalaInternational Conference on Data Electronics and Computing (ICDEC), NEHU, Shillong , 2022
Abstract:
Stain Color Translation of Multi-Domain OSCC Histopathology Images using Attention gated cGAN
Barun Barua , Kangkana Bora , Anup Kr.Das , Gazi N Ahmed , Tashnin RahmanComputerized Medical Imaging and Graphics, Elsevier, vol - 106 [IF 7.422] , 2023 , https://doi.org/10.1016/j.compmedimag.2023.102202
Abstract:
A Blockchain-Based Authentication Scheme for 5G-Enabled IoT, Journal of Network and Systems Management, Springer, (Scopus, SCIE, IF: 3.6)
Bidisha Goswami and Hiten Choudhury, vol: 30 , 2022 , https://doi.org/10.1007/s10922-022-09680-6
Abstract:
5G cellular network is becoming a preferred technology for communication in deployments of the Internet of Things (IoT). However, 5G cellular network is essentially designed for cellular communication. Therefore, there are several areas in IoT over 5G cellular network, where there is scope for further improvement. One such area is development of efficient security mechanisms for authentication of the IoT devices. The authentication protocol currently being used in 5G cellular network maintains the security credentials of the devices at the home network in a centralised manner. Therefore, every time a device needs to be authenticated, the home network has to be communicated. However, considering the IoT scenario where there is large scale deployment of devices, frequent communication with the home network may result in increased communication latency. In this paper, we propose an authentication scheme where security credentials of the IoT devices are stored in a decentralized way using blockchain technology. The scheme is found to be safe and secured, through an informal and a formal security analysis using scyther tool. The smart contracts used in the scheme, when deployed in the ethereum test network, are also found to be efficient. Through experimental performance analysis, the scheme is found to have attained reduced communication latency compared to the existing protocols.
A privacy-preserving mutual authentication scheme for group communication in VANET, Computer Communications, Elsevier, (Scopus, SCIE, IF: 6.0)
Himun Jyoti Nath and Hiten Choudhury, vol: 192 , 2022 , https://doi.org/10.1016/j.comcom.2022.06.024
Abstract:
A Vehicular Ad-Hoc Network (VANET) represents a collection of vehicles that communicate among themselves and the road infrastructure for exchange of information through a wireless network. It provides services like road safety, infotainment, optimized traffic flow, location-based services and other on-demand services. However, due to its intrinsic ad-hoc nature, there are several challenges in the deployment of VANETs. One such challenging issue is ensuring security and privacy of the exchanged messages. Therefore, it is important that the vehicles are properly authenticated and necessary security associations are properly established. Most of the recent works in this area sends plain text messages while communicating, that results in compromise of message confidentiality. Moreover, in majority of these works, an active communication with a trusted authority is required during authentication that results in increased communication latency. This paper puts forward a privacy preserving mutual authentication scheme for group communication in VANET that does not require an active communication with a trusted authority. Furthermore, the proposed scheme use pseudonym for identity privacy and the messages exchanged in the scheme are encrypted before transmission. Formal and informal security analysis shows that the proposed scheme is robust against various security attacks. Through a performance analysis, the scheme is found to be efficient.
Remote Registration and Group Authentication of IoT Devices in 5G Cellular Network, Computers & Security, Elsevier, (Scopus, SCIE, IF: 5.6)
Hemangi Goswami and Hiten Choudhury, vol: 120 , 2022 , https://doi.org/10.1016/j.cose.2022.102806
Abstract:
The Fifth Generation (5G) of cellular mobile network, due its speed and flexibility, will be a preferred communication technology for future deployment of the Internet of Things (IoT). However, with the rapid growth in the number of connected devices, registration and authentication of the devices in 5G cellular network are set to become challenging tasks. Currently, the basis for registration and authentication of the devices in 5G mobile network is the Universal Subscriber Identity Module (USIM) that is provided to every device. But, with large scale deployments in IoT, providing a USIM and authenticating every device individually is going to be arduous. Recently, several group based authentication protocols have been proposed by researchers. Even so, none of these proposals can be easily adopted, since they are not based on the challenge response mechanism used in the 5G Authentication and Key Agreement Protocol (5G-AKA). In this paper, an efficient scheme for remote registration and group authentication of the IoT devices in 5G cellular network is proposed. The scheme is designed to work along with 5G-AKA protocol as its extension. It uses elliptic curve cryptography that is lightweight in nature and is suitable for resource constrained IoT environment. Security analysis and performance analysis shows that the proposed scheme is secured and efficient in comparison to similar recent proposals in the literature.
A lightweight D2D authentication protocol for relay coverage scenario in 5G mobile network, Computer Networks, Elsevier, (Scopus, SCIE, IF: 5.6)
Ponjit Borgohain and Hiten Choudhury, vol: 225 , 109679, 2023 , https://doi.org/10.1016/j.comnet.2023.109679
Abstract:
Mobile networks are set to play a crucial role as backbone network in IoT deployments due to their low cost, broad coverage, high bandwidth, and low latency. However, a challenging security issue prevalent in mobile networks across the various generations including 4G, is identity privacy. In a recent standard for 5G mobile network: 3GPP TS 33.501, an Elliptic Curve Integrated Encryption Scheme (ECIES) is adopted to tackle this issue. While this mechanism seems to provide a reasonable solution for modern smart phones, it may not be best suitable for resource constrained IoT devices because of the computationally intensive calculations involved in elliptic curve cryptography. In this paper, an alternative lightweight scheme for identity privacy of IoT devices in 5G mobile network is proposed. This new scheme called ‘HashXor’ requires only two Hash operations and three Xor operations for the IoT device to achieve its objective. The scheme is found safe and logically correct through security analysis and formal analysis (using AVISPA tool). Through an execution time analysis in the ATmega328P microchip, the scheme is found to be computationally efficient compared to ECIES and few other recent proposals in this area.
Enhancing the Elliptic Curve Integrated Encryption Scheme in 5G mobile network for home network identity privacy, Security and Privacy, Wiley, (ESCI)
Hiten Choudhury, vol: 5 , (ESCI), 2022 , https://doi.org/10.1002/spy2.222
Abstract:
In mobile network, ensuring privacy to the subscriber is an obligation of the mobile operator. It is the responsibility of the operator to ensure that the private information about the subscriber like his/her identity does not get compromised. While adopting technologies with regards to issues like this, operators mostly follow specifications standardized by the third Generation Partnership Project (3GPP). In a recent technical specification published by 3GPP for 5G mobile network, an Elliptic Curve Integrated Encryption Scheme (ECIES) is adopted for identity privacy. However, this scheme does not emphasize on protecting the identity of the home network with which the subscriber is registered. This may make the subscriber vulnerable to tracking by an adversary in a visited network through his/her home network identity. In this paper, we propose an enhanced scheme called scheme for home network identity privacy. Through a formal and an informal security analysis, the proposed scheme is found to be secured. Through a performance analysis, it is found that the scheme achieves its objective of securing the home network identity of the subscriber at the expense of 47% additional computation at the UE in comparison with the execution time that is incurred by ECIES.
Remote Registration and Group based Authentication of IoT over 5G
Henamgi Goswami and Hiten ChoudhuryProceedings of the 23rd International Conference on Distributed Computing and Networking (ICDCN `22), ACM , 240 - 241, 2022 , https://doi.org/10.1145/3491003.3491300
Abstract:
Cellular networks are preferred as a backbone network for IoT environment, due to their wider coverage and high flexibility. Therefore, security and privacy in IoT over cellular networks has attracted the attention of several researchers. Recently, a number of authentication schemes have been proposed for improving the security and privacy in IoT over 5G cellular network using various techniques, like lightweight cryptography, digital signature, group based authentication, blockchain technology, etc. However, it is seen that none of these works are able to address all the security issues. Moreover, the mechanisms currently being used for security in 5G cellular network cannot be adopted as-it-is in IoT because of resource constraint of IoT devices. Therefore, we are working on a novel scheme for remote registration and group-based authentication of IoT devices in 5G mobile network. Security analysis and performance analysis of the scheme, in comparison to recent proposals in the literature, have found the scheme to be secured and efficient.
ECG-NET: A Deep LSTM Autoencoder for Detecting Anomalous ECG
M. Roy, S. Majumder, A. Halder, U. BiswasEngineering Applications of Artificial Intelligence (Elsevier) [IF:7.802] , vol: 124 , 106484(20 pages), 2023 , https://doi.org/10.1016/j.engappai.2023.106484
Abstract:
Automatic Breast Mass Lesion Detection in Mammogram Images
R.K. Bania, A. HalderInternational Journal of Image and Graphics (World Scientific) , 2023 , In press
Abstract:
Computational analysis of gene expression data using bidirectional long short-term memory for disease diagnosis
S. Dasgupta, M. Dutta, A HalderInnovations in Systems and Software Engineering (Springer) , 2022 , https://doi.org/10.1007/s11334-022-00492-0
Abstract:
Traffic Sign Recognition System using Ensemble based Deep Learning Models
D. Dey, S. Majumder, A. HalderIn proc. Of International Conference on Intelligent Systems, Advanced Computing and Communication (ISACC) , 2023 , https://ieeexplore.ieee.org/document/10083886/
Abstract:
An eSIM-based remote credential provisioning and authentication protocol for IoT devices in 5G cellular network, Internet of Things, Elsevier, (Scopus, SCIE, IF: 5.9)
Hemangi, Goswami and Hiten Choudhury, vol: 23 , 100876, 2023 , https://doi.org/10.1016/j.iot.2023.100876
Abstract:
Embedded Subscriber Identity Module (eSIM) offers more flexibility compared to Universal Subscriber Identity Module (USIM). Unlike USIM, eSIM enables the operator to remotely provision security credentials in the devices. Therefore, in future deployments of IoT over cellular networks, eSIMs are more likely to be used in comparison to USIMs. In anticipation, the 3rd generation partnership project (3gpp) has recently published a mechanism for remote credential provisioning of eSIM-enabled IoT devices in 5G cellular networks (Technical Specification: TS 33.899, Release 14, Section 12.2). However, this technical specification does not include an authentication protocol, which is an indispensable part of any secure communication. In this paper, we propose a novel authentication protocol to complement the remote credential provisioning mechanism published in TS 33.899. While developing the protocol, due consideration to resource constraints of IoT devices is given by using lightweight cryptographic techniques like elliptic curve cryptography, one-way hash functions, XOR operations, etc. Security analysis of the proposed protocol using BAN logic and AVISPA shows the protocol to be secure. Performance analysis, involving the execution of the protocol in Arduino Uno Rev3 microcontroller board and a workstation, shows the protocol to be efficient in comparison to other similar proposals.
Privacy-Preserving Authentication Protocols in Vanet, SN Computer Science, Springer Nature, (Scopus)
Himun Jyoti Nath and Hiten Choudhury, vol: 4 , 589, 2023 , https://doi.org/10.1007/s42979-023-02122-3
Abstract:
Vehicular Ad hoc Network (VANET) is a versatile and ad hoc network, where the vehicles must be authenticated before sharing any critical information. During authentication, privacy of the users must be preserved. There are several surveys on privacy-preserving authentication schemes in VANET. However, none of them are focused on the ability of the schemes to address different security issues and their robustness against security attacks. In this paper, we present a review on various privacy-preserving authentication schemes in VANET. These schemes may be categorized into several types like symmetric/asymmetric key cryptography-based schemes, digital signature-based schemes, ID cryptography-based schemes, pseudonym-based schemes, homomorphic encryption-based schemes, and blockchain-based schemes. A comprehensive study of the prominent schemes, with regards to their effectiveness in addressing different security issues and their robustness against possible attacks, has been performed. Open issue and scope for future work are also highlighted.
A Group Authentication Scheme for IoT 5G Network Enabled e-Healthcare System, In International Conference on Communication, Electronics and Digital Technology, Springer, Singapore: Springer Nature Singapore
Hemangi Goswami and Hiten Choudhury, pp. 229-244., 2023 , https://doi.org/10.1007/978-981-99-1699-3_15
Abstract:
The Internet of Things (IoT) describes a network, which consists of real-life things/physical objects that can communicate with the virtual world and can make intelligent decisions. The rapid development of IoT has led to new opportunities in various real-time use case scenarios like smart homes, healthcare systems, transportation systems, education systems, agriculture systems, etc. With the growth in different technologies used for e-healthcare system, the numbers of security challenges are increasing day by day. It is due to the fact that it introduces several methods/techniques for medical data collection and data analysis. Different medical information are collected from the patient’s body using medical sensors that are attached to the patient’s body. Since the collected data and information are very sensitive, therefore, the transmission of those information securely over the Internet has become a challenging task. However, fifth-generation (5G) cellular network, because of its flexibility and high speed, has become a preferred alternative for the transmission of those data compared to other cellular networks. In this paper, a group authentication scheme for the e-healthcare systems in fifth-generation cellular network is proposed. In the proposed scheme, registration of the medical sensors is done remotely. The authentication process is performed as an extension of the existing Authentication and Key Agreement protocol for 5G cellular network (5G-AKA). Lightweight cryptographic techniques like one-way hash function, XOR operation, and elliptic curve cryptography (ECC) are used, which are suitable for resource-constrained IoT environment. The results obtained from the security and performance analysis of the proposed scheme show it to be secure and efficient.
Using Blockchain for Fast Re-Authentication in 5G Cellular Network, International Conference on Communication, Electronics and Digital Technology, Springer Nature Singapore.
Bidisha Goswami and Hiten Choudhury, 2023 , https://doi.org/10.1007/978-981-99-1699-3_16
Abstract:
In order to serve more users and to provide higher bandwidth, 5G cellular network supports deployment of small cells like femtocells, picocells and microcells. However, a user equipment in 5G cellular network may experience frequent handover, when the subscriber moves from the coverage area of one cell to another. Therefore, for seamless user experience, it is necessary that the re-authentication procedure during handover is made faster. In this paper, we propose a fast re-authentication scheme for handover in 5G cellular network based on blockchain technology. We have considered security requirements like forward secrecy, backward secrecy, anonymity, etc. The scheme shows it is robust against various kinds of security attacks by performing formal and informal security analysis. Through performance analysis, it is found that the protocol achieves its goals with minimum communication and computation overhead.
Lesion Detection in Women Breast’s Dynamic Contrast-Enhanced Magnetic Resonance Imaging using Deep Learning
Sudarshan Saikia, Tapas Si, Darpan Deb, Kangkana Bora, Saurav Mallik, Ujjwal Maulik and Zhongming ZhaoNature Scientific Reports , [IF 4.6], , vol: 13 , 2023 , https://doi.org/10.1038/s41598-023-48553-z
Abstract:
Breast cancer is one of the most common cancers in women and the second foremost cause of cancer death in women after lung cancer. Recent technological advances in breast cancer treatment offer hope to millions of women in the world. Segmentation of the breast’s Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) is one of the necessary tasks in the diagnosis and detection of breast cancer. Currently, a popular deep learning model, U-Net is extensively used in biomedical image segmentation. This article aims to advance the state of the art and conduct a more in-depth analysis with a focus on the use of various U-Net models in lesion detection in women’s breast DCE-MRI. In this article, we perform an empirical study of the effectiveness and efficiency of U-Net and its derived deep learning models including ResUNet, Dense UNet, DUNet, Attention U-Net, UNet++, MultiResUNet, RAUNet, Inception U-Net and U-Net GAN for lesion detection in breast DCE-MRI. All the models are applied to the benchmarked 100 Sagittal T2-Weighted fat-suppressed DCE-MRI slices of 20 patients and their performance is compared. Also, a comparative study has been conducted with V-Net, W-Net, and DeepLabV3+. Non-parametric statistical test Wilcoxon Signed Rank Test is used to analyze the significance of the quantitative results. Furthermore, Multi-Criteria Decision Analysis (MCDA) is used to evaluate overall performance focused on accuracy, precision, sensitivity, F1-score, specificity, Geometric-Mean, DSC, and false-positive rate. The RAUNet segmentation model achieved a high accuracy of 99.76%, sensitivity of 85.04%, precision of 90.21%, and Dice Similarity Coefficient (DSC) of 85.04% whereas ResNet achieved 99.62% accuracy, 62.26% sensitivity, 99.56% precision, and 72.86% DSC. ResUNet is found to be the most effective model based on MCDA. On the other hand, U-Net GAN takes the least computational time to perform the segmentation task. Both quantitative and qualitative results demonstrate that the ResNet model performs better than other models in segmenting the images and lesion detection, though computational time in achieving the objectives varies.
Multi-objective distributed cooperative spectrum sensing for cognitive radio networks using greedy-based coalitional game
P. Chauhan, S.K. Deka, and N. SarmaPhysical Communication (Elsevier) , vol: 61 , 2023 , https://doi.org/10.1016/j.phycom.2023.102211
Abstract:
Machine Learning approach to study social determinants of chronic illness in India: A comparative analysis
Aakanksha Agarwala, Barun Barua, Genevieve Chyrmang, Manab Deka, Kangkana BoraIndian Journal of Public Health (Accepted), IF 1.700, Scopus , 2024
Abstract:
An Empirical Evaluation of Research on “Library Management” at the Doctoral Level in India: A Study of the Last 50 Years from 1971 to 2020
Nishant Kashyap Ghatowar; Deepjyoti KalitaOpen Information Science , vol: 7 , 2023 , https://doi.org/10.1515/opis-2022-0138
Abstract:
The current study is undertaken to report a statistic and study the growth of doctoral research in India under the domains of “library management” in the last 50 years from 1971 to 2020. Two central repositories of India, i.e. INFLIBNET “Shodhganga” and INFLIBNET “INDCAT” services, were used to curate data for the PhD theses for the studied period. A hypothesis was formulated and statistically proved that research on library management has witnessed significant growth during the period. A total of 304 theses were produced by 89 universities during the period that dealt with the subject of library management, out of which Gauhati University produced the highest (4.23% of the total). Northeastern and Southern India universities have a higher thesis productivity average per institution than the national average during the studied period. A positive correlation was found between the age of the Library and Information Science (LIS) department with thesis productivity. Significantly, several non-LIS departments have produced PhDs in the areas of library management during the studied period. Decade-wise growth study revealed that after the year 2000, Financial Planning, Human resource management, Total Quality Management, and Management of Digital resources are some prominent micro-level areas of the doctoral theses of Indian universities in the last 50 years.
Silver linings in Indian Research Funding Scenario: A Study of Scientometrics Dimensions of Research funded by Department of Atomic Energy during 2003-2017
Deepjyoti KalitaJournal of Indian Library Association , vol: 58 , 125-142, 2022
Abstract:
The aim of the present study is to conduct quantitative and qualitative analysis of
research performed in institutes supported by the Department of Atomic Energy
(DAE), Government of India. Articles from the Scopus database were searched
and identified where funding source was acknowledged as DAE. Around 8240
articles were retrieved. The study revealed the exponential growth in immediacy
index in the research, funded by DAE, indicating the trendiness in research with
cited to uncited articles ratio of 12.55:1. Leimkuhlar model of Bradford’s distribution
yielded 26 core journals where 25.13% of the published articles were distributed.
India has a strong collaboration with USA, China, Germany and Russia in the
research activity funded by DAE. The analysis also found that DAE is providing
ample funding for research under the areas of Biochemistry, Biology, Medicine,
Spectroscopy and particle property studies in the selected time period i.e. 2003-
2017. DAE being a premier government research funding organization in India,
the outcome of the study may helpful to the government and policy makers of
DAE for deciding their future course of action in providing budgets for research.
Fuzzy risk analysis based on a similarity measure of fuzzy numbers and its application in crop selection
M K Gogoi, R ChutiaEngineering Applications of Artificial Intelligence , vol: 107 , 104517, 2022 , 10.1016/j.engappai.2021.104517
Abstract:
Crop selection is an important task for optimum output, as it involves various risk factors. Hence, it requires performing risk analysis on crop selection. Generally, these risk factors involved in crop selection can be assessed by probabilistic methods, which require lots of data and are very expensive. As such, an alternative to probabilistic analysis, possibilistic analysis can be performed where the data involved are linguistic variables. These linguistic variables can be observed as fuzzy numbers, in which case fuzzy risk analysis plays an important role. Generally, in the process of fuzzy risk analysis, the final risks are fuzzy numbers, which have to be transformed into linguistic variables, so that the final risks become communicable to the general audience. The similarity measure is such a tool that helps in the process of transformation. Literature reveals lots of similarity measures since its development. This happens as there is not a single universally accepted measure. In this work, an attempt is being made to develop a novel measure of similarity between fuzzy numbers. Generally, the existing measures do not comply with the basic properties of a similarity measure. Nevertheless, the current measure oath to follow some reasonable properties of the similarity measure.
Two new similarity measures for intuitionistic fuzzy sets and its various applications
B Gohain, R Chutia, P Dutta, S GogoiInternational Journal of Intelligent Systems , 2022 , 10.1002/int.22802
Abstract:
In this paper, two new tools of decision-making problems, namely similarity measures between intuitionistic fuzzy sets, are being forwarded. In general, parameters like the difference of membership degrees and the difference of nonmembership degrees are very prominent factors while constructing these tools. Various studies are evident which tried to incorporate concepts like the cross-evaluation factor and the difference of hesitancy factors. In some studies, it is claimed that the use of the hesitancy parameter is not proper. In this study, the hesitancy factor is being incorporated effectively. Furthermore, another prominent parameter is the difference in the minimum of cross-evaluation factor along with the difference in the maximum of cross-evaluation factor, which is not being used earlier. The incorporation of these parameters produces outperforming results, and the limitations of the existing methods are overcome. The numerical examples discussed to show the performance of the proposed distance measure. Furthermore, the applicability of the proposed similarity measures is exhibited by various applications in pattern recognition, face-mask selection, and clustering problems.
Ranking of generalized fuzzy numbers based on accuracy of comparison
M. Adabitabar Firozja, F. Rezai Balf, B. Agheli, R. ChutiaIranian Journal of Fuzzy Systems , vol: 19 , 49-61, 2022 , 10.22111/IJFS.2022.6787
Abstract:
Ranking generalized fuzzy numbers plays an important role in many applied models and, in particular, decision-making procedures. In ranking process of two generalized fuzzy numbers, it is natural to compare the sets of values in support of two generalised fuzzy numbers. Accordingly, the comparison of a real number and a generalised fuzzy number as well as two generalised fuzzy numbers have to be considered. On the other hand, it is seen that a definitive process of comparison of a real number and a generalised fuzzy number, as well as two generalised fuzzy numbers, is not possible. So in this study, a method for comparing a real number and a generalised fuzzy number with a degree of accuracy (between a zero and one) is defined and then the method is generalized to compare two generalised fuzzy numbers. In general, an index to rank a real number and generalised fuzzy number is constructed. Eventually, this index is extended to rank two generalised fuzzy numbers based on the concept of accuracy of comparison. The advantage of our method is that it can compare two generalised fuzzy numbers with an accuracy of comparison. Also, a definition is introduced to make a definitive comparison. Finally, the proposed method is illustrated by some numerical examples.
Magnetohydrodynamic unsteady natural convective flow in a porous medium over a moving infinite cylinder
Ashish PaulHeat Transfer , vol: 51 , 6548–6562, 2022 , https://doi.org/10.1002/htj.22612
Abstract:
The effect of the magnetic field on the unsteady natural convective one‐dimensional laminar flow of an incompressible viscous and slightly electrically conducting fluid over a vertical cylinder is investigated analytically. The cylinder is assumed to be embedded in a porous medium, and it moves with a uniform velocity along the vertically upward direction. The boundary layer flow equations are converted to a nondimensional form using appropriate non‐dimensional parameters, and the closed-form solutions are obtained using the Laplace transform method. Fluid velocity depends on radial distance, time, magnetic parameter, Grashof number, permeability parameter, and Prandtl number. Graphical and tabulated results of the fluid velocity profile and shear stress based on the analytical solutions are presented and discussed. The analytical solution reveals that the unsteady fluid velocity tends to a steady state at a large time. The present study demonstrates that increased porosity leads to enhancement in the fluid velocity, whereas the transverse magnetic field resists the fluid velocity. Furthermore, the absolute value of shear stress decreases with a decrease in porosity of the medium or an increase in magnetic field effect.
Numerical investigation on the thermal transportation of MHD Cu/Al2 O3-H2O Casson-hybrid-nanofluid flow across an exponentially stretching cylinder incorporating heat source.
Ashish Paul, Tusar Kanti Das, Jintu Mani NathPhysica Scripta , vol: 97 , 085701, 2022 , https://doi.org/10.1088/1402-4896/ac7981
Abstract:
This paper investigates the stagnation point flow and heat transfer of MHD boundary layer Casson hybrid nanofluid through a porous space across an exponentially stretched cylinder. The heat source impact is also considered in the model. A3-stage Lobatto IIIa formula, Bvp4c, is operated to obtain the numerical findings. The influences of dimensionless parameters, namely Prandtl number, Reynolds number, heat source parameter, and Casson fluid parameter on Skin-friction coefficient, velocity, thermal profile, and Nusselt number, are portrayed graphically and depicted through tables. The significant findings indicate that the hybrid Casson nanofluids have a higher thermal conductivity when compared to the Casson nanofluids. As a result, the Casson hybrid nanofluid fluid has a significant impact on increasing heat processes. It has been investigated that the coefficient of the
absolute Skin friction for Casson hybrid nanofluid is raised up to 29% compared to Casson nanofluids. The effective heat transfer rate of Casson hybrid nanofluid is improved over 9%compared to Casson nanofluid. As the heat source and Casson fluid parameters are incremented, the numeric values of the Nusselt number reduce.
Discrete similarity measures on Pythagorean fuzzy sets and its applications to medical diagnosis and clustering problems
B Gohain, R Chutia, P DuttaInternational Journal of Intelligent Systems , 2022 , https://doi.org/10.1002/int.23057
Abstract:
Darcy–Forchheimer MHD radiative flow through a porous space incorporating viscous dissipation, heat source, and chemical reaction effect across an exponentially stretched surface
Ashish Paul, Tusar Kanti DasHeat Transfer, Wiley , vol: 52 , 807–825, 2023 , https://doi.org/10.1002/htj.22717
Abstract:
Abstract
The impacts of viscous dissipation, Brownian motion, and the thermophoresis caused by temperature gradient on the steady two-dimensional incompressible chemically reactive and radiative flow of traditional fluid through an exponentially stretched sheet embedded in a Darcy porous media are explored by approaching boundary layer analysis. A magnetic field effect is also addressed along the transverse direction of the horizontal stretched sheet. With the implementation of some suitable nondimensional quantities, the regulating nonlinear partial differential equations, which represent the flow geometry, are transformed into coupled nonlinear ordinary differential equations. To acquire the numerical findings from this set of equations, a three-stage Lobatto IIIa, in-built MATLAB scheme named, Bvp4c is used. The effects of the dimensionless physical factors on the flow, heat, and concentration profile, as well as on the coefficient of drag force and the rate of thermal and mass transit at the surface, are graphically and numerically depicted. The thermal profile, as well as the magnitude of the coefficient of the drag force and the Sherwood number, is found to be escalated with the Darcy–Forchheimer factor, but the depreciation in the value of temperature gradient at the wall is noticed for the same.
Radiation effect on Transient Natural Convective MHD Flow over a fixed Cylinder in a permeable medium with Heat and Mass Transport
Ashish PaulInternational Journal of Ambient Energy , 1-9, 2022 , https://doi.org/10.1080/01430750.2022.2128873
Abstract:
Abstract
The thermal radiation impact on the unsteady magnetohydrodynamic flow of a Newtonian fluid past a stationary vertical cylinder with heat and solute transfer has been investigated. The viscous fluid is slightly electrically conductive, and the stationary cylinder is placed in a permeable medium. The linear PDEs that govern the flow is transformed to non-dimensional by suitable non-dimensional quantities, and the standard Laplace transform approach is used to derive the closed-form solutions. The impacts of the flow parameters are discussed through a table and graphs. It is found that the unsteady fluid velocity enhances with a rise in radiation parameter, permeability parameter and time, whereas it falls with reduced magnetic effect. The absolute skin friction value rises with an increase in thermal radiation and porosity parameter but falls with a rise in Schmidt number and transverse magnetic field.
Existence of Solution of Infinite Systems of Singular Integral Equations of Two Variables in C(I×I,l_p ) with I = [0, T], T > 0 and 1
Anupam Das, Bipan Hazarika, K. SadaranganiFilomat , vol: 36 , 3013–3023, 2022 , https://doi.org/10.2298/FIL2209013D
Abstract:
In this article, we discuss the solvability of infinite systems of singular integral equations of
two variables in the Banach sequence spaces C(I × I, ℓp) with I = [0, T], T > 0 and 1 < p < ∞ with the help
of Meir-Keeler condensing operators and Hausdorff measure of noncompactness. With an example, we
illustrate our findings.
A novel defuzzification approach of ranking parametric fuzzy numbers based on the value and ambiguity calculated at decision levels
R ChutiaInternational Journal of Uncertainty, Fuzziness and Knowledge-Based Systems , vol: 30 , 847-878, 2022 , 10.1142/S0218488522500258
Abstract:
Application of measure of noncompactness on integral equations involving generalized proportional fractional and Caputo-Fabrizio fractionan integrals
Anupam Das, Bipan Hazarika, Nihar Kumar Mahato, Vahid ParvanehFilomat , vol: 36 , 2022
Abstract:
Using Petryshyn's fixed point theorem, we show the existence of solution to fractional integral equations, including generalized proportional and Caputo Fabrizio fractional integrals. We also use appropriate examples to support our findings.
Meir-Keeler Condensing Operator to Prove Existence of Solution for Infinite Systems of Differential Equations in the Banach Space and Numerical Method to Find the Solution
Mohsen Rabbani, Anupam Das, Bipan Hazarika, Reza ArabFilomat , vol: 36 , 2022
Abstract:
In this paper, we establish the existence of solution for infinite systems of differential equations
in the Banach sequence space n(ϕ), ℓp(1 ≤ p < ∞) and c by using Meier-Keeler condensing operators. With
the help of examples we illustrate our results in the sequence spaces. Also for validity of the results, we
find an approximation of solution by using a suitable method with high accuracy.
Existence of an infinite system of fractional hybrid differential equations in a tempered sequence space
. Anupam Das, Bipan Hazarika, Bhuban Chandra DeuriFractional Calculus and Applied Analysis , vol: 25 , 2022 , , https://doi.org/10.1007/s13540-022-00084-6.
Abstract:
In this article, the existence of the solution of infinite system of fractional hybrid
differential equations with initial conditions by reducing them to integral equations in
the space C(I ,m(θ)β) is discussed based on Darbo fixed point theorem. In the end, a
suitable example to strengthen the article is included.
Solution of Hammerstein type integral equation with two variables via a new fixed point theorem
Anupam Das, Bhuban Chandra DeuriThe Journal of Analysis , 2022 , https://doi.org/10.1007/s41478-022-00537-4
Abstract:
In this manuscript, a new fixed point theorem(FTP) involving the measure of noncompactness
is discussed. This new FTP is a generalization of Darbo’s FTP in Banach space. Further, this newly established FTP is applied to analyze the solvability of Hammerstein type integral equation in two variables. At last, we provide examples to justify our results.
Solvability of infinite system of general order differential equations via generalized Meir-Keeler condensing operator and semi-analytic method
Anupam Das, Mohsen Rabbani, Bipan Hazarika, S. A. MohiuddineInt. J. Nonlinear Anal. Appl. , 2022 , http://dx.doi.org/10.22075/ijnaa.2022.26862.3431
Abstract:
In this article, a new fixed point theory and generalized condensing operator have been established to prove the existence of solutions for an infinite system of differential equations of nth order. Also, some interesting examples are employed to support the findings. To validate our discussion the solutions of the examples are approximated by an iterative algorithm with high accuracy. The algorithm is convergent and constructed based on the modified homotopy perturbation method.
Iterative algorithm and theoretical treatment of existence of solution for (k, z)-Riemann–Liouville fractional integral equations,
Anupam Das, Mohsen Rabbani, S.A. Mohiuddine, Bhuban Chandra DeuriJ. Pseudo-Differ. Oper. Appl. , vol: 13 , 2022
Abstract:
In our discussion, existence of solution for fractional integral equation (FIE) involving
(k, z)-Riemann–Liouville fractional integral is studied. To achieve this goal, first using
shifting distance functions,we establish a newgeneralization ofDorbo-type fixed point
theorem, in short,weshallwriteDFPT, and thenweapply ourDFPTon aforementioned
FIE to establish the existence result. Also, our results will be verified by considering
a suitable example. Moreover, an approximate solution of the example is given via a
convergent iterative algorithm constructed by modified homotopy perturbation (MHP)
method with a high accuracy.
A fixed point theorem using condensing operators and its applications to Erdélyi–Kober bivariate fractional integral equations
Anupam Das, Mohsen Rabbani, Bipan Hazarika, Sumati Kumari PandaTurkish Journal of Mathematics , vol: 46 , 2022
Abstract:
The primary aim of this article is to discuss and prove fixed point results using the operator type condensing
map, and to obtain the existence of solution of Erdélyi–Kober bivariate fractional integral equation in a Banach space. An instance is given to explain the results obtained, and we construct an iterative algorithm by sinc interpolation to find an approximate solution of the problem with acceptable accuracy.
Solution of a Fractional Integral Equation Using the Darbo Fixed Point Theorem
Bhuban Chandra Deuri, Marija V. Paunovi´c, Anupam Das, Vahid ParvanehJournal of Mathematics , vol: 2022 , 2022
Abstract:
The concept of measure of noncompactness in a Banach space is used in this paper to extend some tripled fixed point theorems.We prove the existence of fractional integral equation solutions using a generalized Darbo fixed point theorem. To demonstrate the validity of the main result, an example is provided.
Existence of Solutions for Nonlinear Integral Equations in Tempered Sequence Spaces via Generalized Darbo-Type Theorem
S.A. Mohiuddine, Anupam Das , Abdullah AlotaibiJournal of Function Spaces , vol: 2022 , 2022
Abstract:
Two concepts—one of Darbo-type theorem and the other of Banach sequence spaces—play a very important and active role in ongoing research on existence problems. We first demonstrate the generalized Darbo-type fixed point theorems involving the concept of continuous functions. Keeping one of these theorems into our account, we study the existence of solutions of system of nonlinear integral equations in the setting of tempered sequence space. Moreover, a very interesting and illustrative example is designed to visualize our findings.
Solvability of fractional integral equations via Darbo’s fixed point theorem
Bhuban Chandra Deuri, , Anupam DasJ. Pseudo-Differ. Oper. Appl. , vol: 13 , 2022
Abstract:
A fixed point theorem has been generalized herein, using a newly constructed contraction
operator. In addition to this, the solvability of fractional integrals based on this
generalized fixed point theorem along with suitable examples have also been reported
in this article.
Extension of Darbo’s fixed point theorem via shifting distance functions and its application
Hemant Kumar Nashine, Anupam DasNonlinear Analysis: Modelling and Control , vol: 27 , 2022
Abstract:
In this paper, we discuss solvability of infinite system of fractional integral equations
(FIE) of mixed type. To achieve this goal, we first use shifting distance function to establish a new
generalization of Darbo’s fixed point theorem, and then apply it to the FIEs to establish the existence
of solution on tempered sequence space. Finally, we verify our results by considering a suitable
example.
Application of a generalization of Darbo’s fixed point theorem via Mizogochi-Takahashi mappings on mixed fractional integral equations involving (k, s)-Riemann-Liouville and Erd´elyi-Kober fractional integrals
Anupam Das, V. Parvaneh B. Chandra Deuri, Z. BagheridInt. J. Nonlinear Anal. Appl. , vol: 13 , 2022
Abstract:
We have established the solvability of fractional integral equations with both (k, s)-Riemann-Liouville
and Erd´elyi-Kober fractional integrals using a new generalized version of the Darbo’s theorem using
Mizogochi-Takahashi mappings and justify the validity of our results with the help of suitable
examples.
A distance measure for optimistic viewpoint of the information in interval-valued intuitionistic fuzzy sets and its applications
B Gohain, R Chutia, P DuttaEngineering Applications of Artificial Intelligence , vol: 119 , 105747, 2023 , 10.1016/j.engappai.2022.105747
Abstract:
Existence of a solution to an infinite system of weighted fractional integral equations of a function with respect to another function via a measure of noncompactness
Anupam Das, Marija Paunović, Vahid Parvaneh, Mohammad Mursaleen, Zohreh BagheriDemonstratio Mathematica , vol: 55 , 1-11, 2023 , https://doi.org/10.1515/dema-2022-0192
Abstract:
On Non-Comaximal Graphs of Ideals of Commutative Rings
Bikash Barman, Kukil Kalpa RajkhowaArmenian Journal of Mathematics , vol: 15 , 2023 , https://doi.org/10.52737/18291163-2023.15.2-1-8
Abstract:
A fixed point result via new condensing operator and its application to a system of generalized proportional fractional integral equations
Anupam Das, Reena Jain, Hemant Kumar NashineJ. Pseudo-Differ. Oper. Appl. , vol: 14 , 2023 , https://doi.org/10.1007/s11868-023-00519-5
Abstract:
Thermal and mass transfer aspects of MHD flow across an exponentially stretched sheet with chemical reaction
Ashish Paul, Tusar Kanti DasInternational Journal of Ambient Energy , 2023 , https://doi.org/10.1080/01430750.2023.2179110
Abstract:
This investigation deals with the two-dimensional steady problem incorporating the magneto hydrodynamic effect with three distinct boundary layer streams of fluid across an exponentially stretched sheet under the influence of thermal radiation and chemical reactions. The concurrent flow model also accounts for the effect of Thermophoresis and Brownian movement, caused by temperature and concentration gradients between two boundaries, respectively. By using suitable similarity transformation variables, the nonlinear systems of governing PDEs are transformed into a system of nonlinear ODEs. The findings, obtained by using the Bvp4c strategy, are analysed and depicted graphically and through tables. Furthermore, the Nusselt number, Sherwood number and drag coefficient, which are crucial for industrial applications, are also shown in the table to demonstrate the impact of dimensionless physical parameters. In response to a steady rise in Lewis number and chemical reaction parameter, the heat transit rate tends to decline while the species transit rate increases.
The existence of a solution to more general proportional forms of fractional integrals via a measure of noncompactness
Bhuban Chandra Deuri, Anupam DasInt. J. Nonlinear Anal. , 1-9, 2023 , http://dx.doi.org/10.22075/ijnaa.2023.25659.3083
Abstract:
A fixed point theorem is proved using a newly constructed contraction operator in this article, and the solvability of a more general type of fractional integrals based here on the proportional derivative is analyzed. We also use suitable examples to illustrate our findings.
Keywords: Measure of noncompactness(MNC), integral equation, Fixed point
2020 MSC: 35K90, 47H10
Finite element method for hyperbolic heat conduction model with discontinuous coefficients in one dimension
Tazuddin AhmedProceedings: Mathematical Sciences , vol: 6 , 2022 , https://doing.org/10.1007/s12044-021-00646-3
Abstract:
Solvability of (P,Q)-functional integral equations of fractional order using generalized Darbo’s fixed point theorem
Anupam Das, Bipan Hazarika, Mohammad Mursaleen, Hemant Kumar Nashine, Vahid ParvanehFilomat , vol: 37 , 7849–7865, 2023
Abstract:
In this article, we establish a generalized version of Darbo’s fixed point theorem via some newly
defined condensing operators and we define a new fractional integral using (P,Q)-calculus and study its
properties. Finally, we apply this generalized Darbo’s fixed point theorem to check the existence of solution
of (P,Q)-functional integral equations of fractional order in a Banach space. We explain the results with the
help of simple examples.
An investigation of the MHD Cu-Al2O3/H2O hybrid-nanofluid in a porous medium across a vertically stretching cylinder incorporating thermal stratification impact
Ashish PAUL, Jintu MANI NATH, Tusar KANTI DASJournal of Thermal Engineering , vol: 9 , 799-810, 2023 , 10.18186/thermal.1300847
Abstract:
The thermal aspects of ?? − ??2?3/????? hybrid nanofluid in a porous medium across a ver-tically stretched cylinder with the incorporation of heat sink/source impact are investigated in this numerical study. A magnetic field along the transverse direction of the stretching cylinder and the thermal buoyancy effect is considered in the flow problem. A pertinent similarity vari-able has been employed to simplify the boundary layer equations which govern the flow and convert the coupled nonlinear partial differential equations into a set of non-linear ordinary differential equations. The numerical results are computed using the 3-stage Lobatto IIIa tech-nique, Bvp4c. The impacts of non- dimensional parameters, including Prandtl number, heat source/sink parameter, magnetic parameter, porosity parameter, curvature parameter, ther-mal stratification parameter, and thermal buoyancy parameter on the velocity curve, thermal curve, skin-friction coefficient, and Nusselt number, are illustrated graphically and numeri-cally portrayed in tables. The important results demonstrate that hybrid nanofluids are more thermally conductive than nanofluids. Therefore, the hybrid nanofluid has a considerable im-pact on improving thermal developments. It has been found that the absolute skin friction of the hybrid nanofluid is up to 31% higher compared to the nanofluid. The heat transport rate of the hybrid nanofluid is 7.5% enhanced in comparison to the nanofluid. The influence of heat stratification of the hybrid nanofluid flow is appreciably significant.
Common Fixed Point Theorem of Family of Contraction Maps and Its Applications in Integral Equations
Reza Arab, Bipan Hazarika2, Mohammad Imdad, Anupam DasThai Journal of Mathematics , vol: 21 , 253-263, 2023
Abstract:
The aim of this article is to prove existence of a unique common fxed point for a family
of contractive type self maps on a complete metric space. Finally we apply this theorem to study the
existence and uniqueness of a common solution for functional integral equations.
New fixed point theorems via measure of noncompactness and its application on fractional integral equation involving an operator with iterative relations
Sudip Deb, Hossein Jafari, Anupam Das , Vahid ParvanehJournal of Inequalities and Applications , 2023 , https://doi.org/10.1186/s13660-023-03003-2
Abstract:
In this paper, Darbo’s fixed point theorem is generalized and it is applied to find the existence of solution of a fractional integral equation involving an operator with iterative relations in a Banach space. Moreover, an example is provided to illustrate the results.
Thermally stratified Cu–Al2O3/water hybrid nanofluid flow with the impact of an inclined magnetic field, viscous dissipation and heat source/sink across a vertically stretching cylinder
Ashish Paul, Jintu Mani Nath, Tusar Kanti DasJournal of Applied Mathematics and Mechanics , 2023 , https://doi.org/10.1002/zamm.202300084
Abstract:
A numerical study of the thermally stratified flow of H2O based Cu − Al2O3 hybrid nanofluid over a linearly stretching cylinder placed vertically in a porous media has been performed. The influences of viscous dissipation, thermal source/sink, and an inclined magnetic field were also considered. Using appropriate similarity transformations, the non-linear mathematical equations of the flow model are translated into a dimensionless form. The in-build finite difference Matlab code Bvp4c is used to attain the numerical solution of the transformed non-linear ordinary differential equations (ODEs). Influences of nanoparticles when added to the water and also the flow parameters’ impacts on the flow rate and thermal transport rate are shown in graphs and tables. The results showed that the absolute value of the shear stress of the hybrid nanofluids was enhanced by up to 33% compared to the considered nanofluid. The study also revealed that the heat transport rate in the convective flow region was much higher in hybrid nanofluid as compared to nanofluid. For Cu − Al2O3/water hybrid nanofluid, the temperature went negative for high thermal stratification. The present study has important implications for the design and optimization of heat transfer devices that use thermally stratified hybrid nanofluids. The results also provide novel insights into the flow behavior of these fluids, that can be used to improve our understanding of their physical properties.
Existence of solutions for infinite system of nonlinear q-fractional boundary value problem in Banach spaces
S. A. Mohiuddin,∗ , Anupam Das , Abdullah AlotaibiFilomat , vol: 37 , 2023 , https://doi.org/10.2298/FIL2330171M
Abstract:
Studying various fixed point theorems on Banach spaces such as the Darbo’s fixed point theorem, has recently proved to be quite effective while doing research on existence problems. We here use a contraction operator to demonstrate a modified Darbo-type fixed point result with the intention to study the existence of solutions of infinite system of nonlinear q-fractional boundary value problem in the Banach spaces. Towards the end, reasonable example is presented to validate our findings.
Comparative flow and thermal transfer aspects of Casson-Williamson Hybrid Nanofluid
Tusar Kanti Das, Ashish PaulLatin American Applied Research , vol: 54 , 319-327, 2024
Abstract:
Mixed Convection of Shear-Thinning Hybrid Nanofluid Flow Across a Radiative Unsteady Cone with Suction and Slip Effect
Ashish Paul, Neelav Sarma, Bhagyashri PatgiriMaterials Today Communications , vol: 37 , 2023 , 10.1016/j.mtcomm.2023.107522
Abstract:
The present study examines the intricate dynamics of flow velocities, temperature distribution, and concentration profiles within Casson hybrid nanofluids as they traverse an unsteady vertical rotating cone, accounting for suction velocity and slip effects. The investigation dissects shear stress rates and thermal and mass transfer rates, leveraging the computational power of MATLAB's bvp4c method to tackle the problem's high non-linearity. The research extends to explore the interplay of magnetic parameters, radiation parameters, thermophoresis, Brownian motion, and chemical reactions in the context of Casson hybrid nanofluid flow over an unsteady vertical rotating cone. The incorporation of velocity slip effects and suction velocity emerges as a pivotal catalyst, elevating the rates of heat and mass transfer. Notably, the findings reveal a substantial enhancement in tangential and azimuthal skin friction by 52 % and 34 %, respectively, when transitioning from Casson nanofluid to Casson hybrid nanofluid. Most strikingly, the rate of heat transfer experiences a remarkable surge of 125 % when Casson hybrid nanofluid supplants Casson nanofluid. This research opens up exciting possibilities for improving heat and mass transfer in various industrial applications, making it a compelling contribution to the field of fluid dynamics and nanofluid research.
A generalized Darbo’s fixed point theorem and its applications to different types of hybrid differential equations
Anupam Das, Sudip Deb, Rupanjali Goswami, Tazuddin Ahmed, Zeynab Izadi, Vahid ParvanehBoundary Value Problems , 2023 , https://doi.org/10.1186/s13661-023-01800-8
Abstract:
In this article, a generalization of Darbo’s fixed point theorem using a new contraction operator is obtained to solve our proposed hybrid differential and fractional hybrid differential equations in a Banach space. The applicability of our results with the help of a suitable example has also been shown.
Modified version of fixed point theorems and their applications on a fractional hybrid differential equation in the space of continuous tempered functions
Sudip Deb, Anupam DasJ. Pseudo-Differ. Oper. Appl. , 2023 , https://doi.org/10.1007/s11868-023-00570-2
Abstract:
This article contains modified version of fixed point theorems with the help of freshly made contraction operators and the solvability of a fractional hybrid differential equation involving Caputo fractional derivative by using modified Darbo’s fixed point theorem in the space of continuous tempered functions. The fundamental tool used in the solvability of the fractional hybrid differential equation is the measure of noncompactness approach. Our results indicate the importance of fixed point theorem for finding solutions of the fractional hybrid differential equation and improve some known results, which have wider applications as well. Also, there are two suitable examples are given to illustrate our results.
Thermal and mass transfer analysis of Casson-Maxwell hybrid nanofluids through an unsteady horizontal cylinder with variable thermal conductivity and Arrhenius activation energy
Ashish Paul; Neelav Sarma; Bhagyashri PatgiriNumerical Heat Transfer, Part A: Applications , 2023 , 10.1080/10407782.2023.2297000
Abstract:
In this study, the flow, thermal transfer, and mass transport of Casson-Maxwell hybrid nanofluids are explored. The governing PDEs are converted into nonlinear ODEs using similarity transformations and then solved using MATLAB's Bvp4c scheme. Various non-dimensional parameters’ influences on fluid behaviour and transport are investigated. Results indicate that higher curvature parameter values boost velocity, temperature, and concentration fields, enhancing mass and heat transfer as well as fluid motion. The unsteadiness parameter affects velocity profiles and heat/mass transfer processes. Thermal and mass relaxation times, alongside parameters like thermophoresis, Brownian motion, variable thermal conductivity, Arrhenius activation energy, chemical reaction, and temperature difference ratio, significantly shape temperature and concentration profiles and optimise heat and mass transfer rates. Additionally, combining the Casson and Maxwell hybrid nanofluid models shows marked changes in skin friction performance: absolute skin friction rises by 30%, while heat transmission increases by almost 11% compared to the Casson-Maxwell nanofluid model.
An iterative algorithm to approximate the solution of a weighted fractional integral equation
Anupam Das, Mohsen Rabbani, Bipan HazarikaAsian-European Journal of Mathematics , vol: 17 , 2024 , https://doi.org/10.1142/S1793557123502418
Abstract:
In this paper, we present a new version of Darbo’s theorem to establish the solvability of a weighted fractional integral equation with respect to another function. To justify the validity of our results, a suitable example is provided and we construct an iterative algorithm by Sinc function to approximate the solution of the example.
Thermophoresis and Brownian Motion Influenced Bioconvective Cylindrical Shaped Ag–CuO/H2O Ellis Hybrid Nanofluid Flow Along a Radiative Stretched Tube with Inclined Magnetic Field
Neelav Sarma and Ashish PaulBioNanoScience , 2023 , https://doi.org/10.1007/s12668-023-01280-1
Abstract: This investigation aims to delineate bioconvection in cylindrical-shaped Ag-CuO/H2O Ellis hybrid nanofluid containing gyrotactic microorganisms around a steady stretched cylindrical tube. Considering Brownian and thermophoretic diffusions, along with effects from an inclined magnetic field and slip, we derive a nonlinear system using boundary layer equations. Employing MATLAB’s bvp4c function for numerical solutions, validated against established studies, we observe strong agreement. Graphical and tabular analyses demonstrate the impact of various parameters on velocity, temperature, concentration, gyrotactic microorganism profiles, skin friction coefficient, local Nusselt and Sherwood numbers, and gyrotactic microorganism coefficient, offering valuable interpretations. Observations reveal that the Ellis fluid parameter heightens velocity but reduces temperature, concentration, and gyrotactic microorganism profiles. Conversely, thermophoresis and Brownian motion enhance heat and mass transfer rates, while slip exhibits an opposite trend. Peclet number and bioconvective constants exhibit intriguing but contrary trends with gyrotactic microorganism profiles, yielding notable insights. A comparison between Ellis hybrid nanofluid and Ellis nanofluid reveals approximate variations in skin friction coefficients (up by 46.5%) and Nusselt numbers (down by 4%), suggesting improved aerodynamics and enhanced biomedical heat control for industrial optimization. Moreover, the reduction in Sherwood numbers (down by 56%) suggests potential applications in tailored environmental remediation and the optimisation of substance diffusion in pharmaceutical and biomedical therapeutics. This comprehensive analysis delves into intricate fluid dynamics, offering empirical insights applicable across engineering, biomedical sciences, and environmental remediation domains.
Numerical Assessment of MHD Thermo-mass Flow of Casson Ternary Hybrid Nanofluid Around an Exponentially Stretching Cylinder
Ashish Paul, Neelav Sarma and Bhagyashri PatgiriBioNanoScience , 2024 , https://doi.org/10.1007/s12668-024-01306-2
Abstract:
The present research delves into the intricate dynamics of Darcy-Forchheimer radiative magnetohydrodynamic flow of a Casson ternary hybrid nanofluid through a porous exponentially stretching cylinder, exploring the influence of several pivotal parameters on velocity, thermal, and mass profiles, as well as the rate of shear stress, heat, and mass transfer rates. Arrhenius activation energy and non-uniform heat flux are examined. By employing similarity conversions, the governing PDEs transformed into nonlinear ODEs. These are subsequently addressed computationally through the bvp4c technique within MATLAB for resolution. Physical factors, including the Casson fluid parameter, Darcy-Forchheimer parameter, magnetic field parameter, porosity parameter, radiation parameter, non-uniform heat sink/source parameters, chemical reaction parameter, and Arrhenius activation energy parameter, are analyzed. Significant findings from the investigation are plotted through graphs and tables. The study reveals that the introduction of the Darcy porous effect alters flow characteristics by decreasing velocity while increasing thermal and mass profiles. Additionally, the magnetic, Casson, and porosity parameters collectively reduce velocity but enhance the temperature and concentration curves, while radiation and non-uniform heat flux independently elevate temperature. The Casson fluid parameter decreases shear stress and heat/mass transfer rates, whereas Arrhenius activation energy boosts concentration, and the chemical reaction parameter diminishes it. It has been found that the Casson hybrid nanofluid exhibits an 11% increase in absolute skin friction compared to the Casson nanofluid. However, this increase sharply rises to 52.5% in the case of Casson ternary hybrid nanofluid when compared to Casson nanofluid. Similarly, the heat and mass transfer rates experience significant enhancements of approximately 15.5% and 8%, respectively, in Casson ternary hybrid nanofluid compared to Casson nanofluid. This model’s practical utility lies in predicting impact flow behavior and transfer rates, aiding in optimizing designs for various industrial and engineering applications, like energy systems, or material processing.
Darcy-Forchheimer flow of Ag–ZnO–CoFe2O4/H2O Casson ternary hybrid nanofluid induced by a rotatory disk with EMHD
Ashish Paul, Bhagyashri Patgiri and Neelav SarmaInternational Journal of Ambient Energy , 2024 , https://doi.org/10.1080/01430750.2024.2313697
Abstract:
This study comprehensively inspects the steady, three-dimensional electromagnetohydrodynamics Darcy-Forchheimer slip flow upon a Casson ternary hybrid nanofluid through a porous rotatory disk. The study plunges into the repercussions of key factors namely thermophoresis, chemical reaction, viscous dissipation, Brownian movement, thermal radiation, and activation energy attributes of the ternary hybrid nanofluid. The current endeavour is inspired by the flourishing requirement in several energy-related and industrial applications. A mathematical configuration is formed to express the fluid flow system and heat and nanoparticle mass transpiration processes. Then partial differential equations administrating our mathematical model, are reformed into ordinary differential equations with the assistance of specific similarity conversions and eventually interpreted numerically using the noteworthy bvp4c scheme. The consequences of discrete flow factors upon temperature, concentration, and velocity profiles and Nusselt number, skin friction’s coefficient, and Sherwood number are investigated. The achieved outcomes disclose the electric parameter aids in upgrading the tangential velocity and temperature profiles. The outcomes reveal that for Casson ternary hybrid nanofluid, the heat and mass transpiration rates elevate by 19.23% and 51.28%, respectively, compared to Casson nanofluid whereas skin friction coefficient is retrogressed by approximately 8.96% for Casson ternary hybrid nanofluid compared to ternary hybrid nanofluid.
Transformer oil-based Casson ternary hybrid nanofluid flow configured by a porous rotating disk with hall current
Ashish Paul, Bhagyashri Patgiri and Neelav SarmaZAMM‐Journal of Applied Mathematics and Mechanics , 2024 , https://doi.org/10.1002/zamm.202300704
Abstract:
The present work examines the 3D, incompressible, magnetohydrodynamic, mixed convective, and Darcy-Forchheimer Casson Cu−TiO2−SiO2 /transformer oil ternary hybrid nanofluid flow configured by a porous rotatory disk. This research work takes into account the influences of hall current, thermophoresis, heat absorption/generation, Brownian motion, joule heating, chemical reaction, thermal radiation, activation energy, and velocity slip condition. The administrative partial differential equations (PDEs) that expound the problem are modified into a set of ordinary differential equations (ODEs) by imposing a similarity conversion, which is further solved numerically by adapting the worthy bvp4c scheme. The velocity, thermal, and mass profiles are delineated through graphs, and the features of skin friction coefficient, heat, and mass transmission are also explicated thoroughly via tables. One significant observation of this research is that the Casson parameter weakens transversal velocity whereas a reverse tendency is noticed against the radial velocity. Our obtained outputs affirm that Casson ternary hybrid nanofluid has respectively 10.93 % and 8.86% higher heat deliverance rate when compared to Casson nanofluid and Casson hybrid nanofluid. Besides, the Casson ternary hybrid nanofluid has respectively 33.68 % and 27.52% higher mass deliverance rate when compared to the Casson nanofluid and Casson hybrid nanofluid. Also, the sturdy values of the Casson parameter lessen the skin friction coefficient. The inferences derived from our research may advantageously be used in rotating types of machinery, medical equipment, gas turbine rotators, etc.
Engine oil blended Casson hybrid nanofluid flow along a uniformly heated curved surface with Arrhenius activation energy and suction: A computational study
Neelav Sarma, Ashish PaulHybrid Advances , vol: 5 , 2024 , https://doi.org/10.1016/j.hybadv.2024.100161
Abstract:
The research studies the numerical analysis of an incompressible Casson hybrid nanofluid, composed of Fe3O4–Cu nanoparticles blended with engine oil, flowing over an exponentially stretched curved surface. It explores the effects of an aligned magnetic field, a uniform heat source, activation energy, and suction while maintaining a low Prandtl number. By employing appropriate similarity transformations, the original partial differential equations are converted into ordinary ones and solved using bvp4c in MATLAB. Graphs and tables depict the influence of dimensionless factors on skin friction coefficient, velocity, thermal, and concentration profiles, as well as Nusselt and Sherwood numbers. The computational findings reveal that magnetic field alignment significantly modifies velocity, decreasing it while uniformly enhancing temperature and concentration profiles. Casson fluid behavior in engine oil amplifies temperature and concentration profiles, thereby enhancing heat and mass transfer rates. Moreover, an increased heat source elevates temperature but reduces overall heat transfer. The chemical reaction parameter diminishes concentration, whereas activation energy enhances it, albeit impacting the mass transfer rate conversely. Additionally, suction increases flow resistance, while the stretching parameter exhibits an inverse effect, both positively influencing heat and mass transfer rates at higher values. Practically, these findings offer insights crucial for optimizing heat exchangers, biomedical devices, and cooling systems, enhancing their efficiency and performance. Additionally, they inform the design of industrial processes involving fluid flow, aiding in the development of more effective and sustainable solutions.
Existence of solutions of infinite system of hybrid fractional integro-differential equation
Simasri Deka, Anupam Das, Bhuban Chandra DeuriSão Paulo Journal of Mathematical Sciences , 2024 , https://doi.org/10.1007/s40863-024-00409-8
Abstract:
In this article, by using a new contraction operator we have developed some new fixed point theorem and then applied it to establish the solution of our proposed infinite system of hybrid fractional integro-differential equation in the space c0 and lp. Also, our findings have been shown with some examples.
Inspection of viscoelastic Ag+Cu+Fe3O4+Al2O3/kerosene oil tetra-hybrid nanofluid flow across a stretchable rotating disk with exponentially varying viscosity
Bhagyashri Patgiri & Ashish PaulJournal of Taibah University for Science , 2024 , 10.1080/16583655.2024.2336327
Abstract:
Fluid flow through rotating disks plays a critical role in various applications across daily life, engineering, and industry, including rotor-stator systems, ocean circulation models, and medical equipment. This study investigates the potential of a novel fluid type – tetra-hybrid nanofluids – in such applications. We explore the influence of factors like variable viscosity, thermal radiation, suction/injection, thermophoresis, nanoparticle shape, Deborah number, and Brownian motion on the flow characteristics of a viscoelastic tetra-hybrid nanofluid over a stretchable rotating disk. Employing the bvp4c numerical scheme, we analyze the governing dimensionless equations. The results demonstrate that the tetra-hybrid nanofluid exhibits significantly improved heat transfer rates compared to conventional nanofluids, hybrid nanofluids and tri-hybrid nanofluids with enhancements of 7.43%, 6.27%, and 5.35%, respectively. Additionally, the study reveals that lamina-shaped nanoparticles offer higher heat transport performance compared to spherical and blade-shaped nanoparticles.
MHD Al2O3/Cu-water Casson hybrid nanofluid flow across a porous exponentially stretching sheet
Ashish Paul, Neelav Sarma and Bhagyashri PatgiriLatin American Applied Research , vol: 54 , 2024
Abstract:
Combined Effect of Non-Linear Mixed Convection, and Non-Uniform Heat Source/Sink on Casson Ternary Hybrid Nanofluid Flow Across a Stretched Rotatory Disk
Ashish Paul, Bhagyashri Patgiri and Neelav SarmaJournal of Nanofluids , vol: 13 , 2024 , https://doi.org/10.1166/jon.2024.2136
Abstract:
Computational study of Jeffrey Hybrid nanofluid flow over on a non-uniformly heated permeable exponentially stretching surface with Arrhenius activation energy and inclined magnetic field
Neelav Sarma, Ashish Paul, Bhagyashri PatgiriHybrid Advances , vol: 6 , 100194, 2024 , https://doi.org/10.1016/j.hybadv.2024.100194
Abstract:
Even and odd nonautonomous NLSE hierarchy and reversible transformations
S Nandy, GK Saharia, S Talukdar, R Dutta, R MahantaOptik 247 , vol: 167928 , 2.443, 2021 , https://doi.org/10.1016/j.ijleo.2021.167928
Abstract:
Abstract Under investigation are the nonautonomous Nonlinear Schrödinger equation (NLSE) hierarchies. We have presented the soliton solution of the hierarchy in the most generalized form, namely in terms of the spectral parameter of nonautonomous NLSE spectral problem. We analysed crucial differences between the even order hierarchies and the odd order hierarchies and the corresponding solutions. We have also presented the generalized reversible transformations, which transform the nonautonomous NLSE hierarchy into variable coefficient autonomous NLSE hierarchy. We found that the reversible coordinate transformations are monotonic for odd order hierarchies but not strictly monotonic for even order hierarchies or for a combination of the both. The Jacobian of the transformation is, however, unity in all the transformations. We have identified a set of constraints among the dispersion and the nonlinear coefficients of the general nonautonomous NLSE hierarchy, which are preserved under the transformations. We hope that our analysis provides a universal mathematical platform to study diverse physical systems in nonlinear optics, plasma physics, atomic physics and climate physics.
Phototransferred thermoluminescence characteristics of microcline (KAlSi3O8) under 470 nm blue- and 870 nm infrared-light illumination
J.M. Kalita, M.L. ChithamboApplied Radiation and Isotopes , vol: 181 , 110070, 2022 , https://doi.org/10.1016/j.apradiso.2021.110070
Abstract:
We report phototransferred thermoluminescence (PTTL) induced in microcline by 470 nm blue- and 870 nm infrared-light. A conventional thermoluminescence (TL) glow curve measured from a sample irradiated to 40 Gy produces five composite TL glow peaks P1, P2, P3, P4 and P5 at 90, 123, 166, 298 and 391 °C respectively. The sample produces PTTL peaks also identified as P1, P2, P3 and P4 following illumination by blue or infrared light after irradiation to 40 Gy and preheating to 400 °C. Step-annealing suggests the presence of deep electron traps associated with a signal beyond 500 °C. However, preheating to 500 °C and exposure to blue or infrared light does not produce significant PTTL peaks. For doses between 40 Gy and 100 Gy, the maximum PTTL is emitted within 60 and 150 s of blue light illumination. On the other hand, the same feature under the infrared light illumination occurs within 100–200 s of illumination. PTTL peaks P1, P2, P3 and P4 reproduced under blue light illumination have a linear dose response between 10 Gy and 100 Gy and those reproduced under infrared light illumination have a superlinear dose response between 10 and 100 Gy. In contrast, donor peak P5 in both cases follows sublinear dose response within the same dose range. Fading of PTTL peaks P1, P2, P3 and P4 as well as the donor peak P5 are negligibly small under blue light illumination compared to that of infrared light illumination. PTTL glow curves are also found to be properly reproducible.
Thermoluminescence and optically stimulated luminescence of colemanite-rich borate mineral
J.M. Kalita, Ş. Kaya-Keleş, G.Ö. Çakal, N. Meriç, G.S. PolymerisJournal of Luminescence , vol: 242 , 118580, 2022 , https://doi.org/10.1016/j.jlumin.2021.118580
Abstract:
We report structural, chemical composition, thermal decomposition and stimulated luminescence properties of a colemanite-rich borate (Ca2B6O11•5H2O) mineral collected from Kırka, Eskişehir region of Turkey. X-ray diffraction shows that the colemanite phase has a monoclinic crystal structure. Further, Raman spectroscopic analysis reveals that the sample contains 45.83% of B and 17.93% of CaO. Thermogravimetric analysis indicates that there is removal of hydroxyl groups followed by explosive release of water from the sample at temperature below 200 °C. The sample produces thermoluminescence (TL) and optically stimulated luminescence (OSL) following beta irradiation. A TL glow curve measured at 1 °C/s consists of five glow peaks at ∼145, 175, 215, 267 and 322 °C. The activation energy associated with the peaks are ∼0.73, 0.77, 0.83, 0.90 and 1.19 eV respectively and the frequency factors are ∼106 ‒ 108 s−1. The lifetimes of the traps at room temperature are estimated to be ∼1.42 days to 2.33 × 104 years. The peaks at ∼175, 215 and 267 °C show supralinear dose response between 32 and 16000 Gy whereas the ones at ∼145 and 322 °C show supralinearity between 32 and 2048 Gy. Analysis of the OSL decay curve shows that the decay curve has a ‘fast’-, ‘medium’- and a ‘slow’ component. The dose response of the fast component is found to be linear within 2–4096 Gy and that of the medium- and slow components are found to be superlinear between 2 Gy and 4096 Gy.
Light-induced inter-electron-trap charge movement in annealed Al2O3:C,Mg
M.L. Chithambo, A.J. Lontsi Sob, J.M. KalitaPhysica B: Condensed Matter , vol: 624 , 413438, 2022 , https://doi.org/10.1016/j.physb.2021.413438
Abstract:
Inter-electron-trap charge movement induced under phototransferred thermoluminescence (PTTL) in Al2O3:C,Mg annealed at 700 and 900 °C is reported. Such annealing modifies the emission spectrum and electron trapping states in Al2O3:C,Mg. The glow curve of Al2O3:C,Mg annealed at 700 °C has eight peaks at 46, 76, 100, 170, 199, 290, 330 and 375 °C respectively. In comparison, that of the sample annealed at 900 °C has nine at 49, 80, 100, 174, 206, 235, 290, 335 and 375 °C. The peaks are labelled I, II, III … in that order. Only peaks I-IV re-appear under phototransfer. The PTTL is analysed qualitatively as well as by computational and phenomenological models as systems of an acceptor and multiple donors. Point defects that likely contribute to emergence of PTTL are discussed and are deduced to lie mostly in the oxygen sub-lattice.
Phototransferred thermoluminescence of BeO: Time-response profiles and mechanisms
M.L. Chithambo, J.M. KalitaJournal of Applied Physics , vol: 130 , 195101, 2021 , https://doi.org/10.1063/5.0067758
Abstract:
Phototransferred thermoluminescence (PTTL) from BeO is reported. The conventional TL glow curve has five peaks, I–V, at 50, 182, 283, 437, and 535 °C when measured at 1 °C s−1 The dominant one is peak II. Only the first three reappear under phototransfer. Electron traps for peaks IV and V weakly contribute to the PTTL. The PTTL at peak III, supposedly associated with these weak donors, is counterintuitively intense. All PTTL peaks are affected by light-induced fading, thermal quenching, and all but peak II by thermal fading. The activation energy for thermal quenching was found as 0.56±0.020.56±0.02, 0.53±0.050.53±0.05, and 0.94±0.07eV0.94±0.07eV using peaks I, II, and III, respectively. Electronic processes relevant in the PTTL of BeO are discussed. PTTL time-response profiles are analyzed using systems of coupled linear differential equations as well as by theoretical modeling.
Thermally-assisted optically stimulated luminescence from deep electron traps in microcline
J.M. Kalita, M.L. ChithamboRadiation Measurements , vol: 154 , 106786, 2022 , https://doi.org/10.1016/j.radmeas.2022.106786
Abstract:
We report thermally-assisted optically stimulated luminescence (TA-OSL) of microcline (KAlSi3O8) from Sri Surya Pahar hill in Assam state, North-Eastern India. To study the luminescence associated with deep electron traps, a beta-irradiated sample was first heated to 500 °C at 1 oCs−1 to deplete all electron traps accessible up to this temperature. Thereafter, the sample was illuminated by 470 nm blue- or 870 nm infrared light at various temperatures between 30 and 300 °C and TA-OSL associated with deep electron traps recorded. The intensity of TA-OSL increased with measurement temperature. The TA-OSL decay curves measured under both types of illumination can be described by a sum of two exponential components. Further, the TA-OSL stimulated by blue light is more intense than that corresponding to infrared light. The TA-OSL is consistent with the presence of at least two types of deep electron traps with differing values of the activation energy for thermal assistance. As regards dose response, the TA-OSL intensity increases sublinearly with dose between 100 and 1000 Gy.
Processes related to phototransfer under blue- and green-light illumination in annealed Al2O3:C,Mg
M.L. Chithambo, J.M. Kalita, N.M. TrindadeJournal of Applied Physics , vol: 131 , 245101 , 2022 , https://doi.org/10.1063/5.0094547
Abstract:
Phototransferred thermoluminescence (PTTL) of Al2O3:C,Mg induced by 470 nm blue, 525 nm green, and 870 nm infrared light is reported. Although its conventional TL glow curve measured during heating to 600 °C has seven peaks (labeled I–VII), only peak II is reproduced under phototransfer, except when the sample is preheated to 180 °C when peak IV also re-appears. The dependence of PTTL intensity on the duration of illumination for both PTTL peaks is analyzed using phenomenological and kinetic models as systems of acceptor and donors, with the number of the latter determined by experiment. The intensity of PTTL increases with the temperature of illumination with an activation energy of thermal assistance of either 0.015 ± 0.002 or 0.047 ± 0.002 eV when either 470 or 525 nm light is used but decreases at elevated temperatures with an activation energy of thermal quenching equal to 0.51 ± 0.02 eV independent of illumination wavelength. The long term behavior of time-response profiles for a system of one acceptor and a single donor, as an exemplar, as studied by stability theory, shows an unstable critical point. Mechanisms for the PTTL are discussed and the emission is ascribed to electron centers in the oxygen sub-lattice.
Concerning a hole trap in α-Al2O3:C,Mg
J.M. Kalita, M.L. ChithamboJournal of Applied Physics , vol: 132 , 015103, 2022 , https://doi.org/10.1063/5.0092064
Abstract:
We report the existence of a hole trap in α-Al2O3:C,Mg as determined using thermoluminescence (TL) and optically stimulated luminescence (OSL). The associated experiments are based on the hypotheses that if a TL glow peak is associated with a hole trap in the glow curve of α-Al2O3:C,Mg, that hole trap will not participate in any light-induced electron-transfer process and its removal will not cause the OSL intensity to decrease. To examine the first hypothesis, a TL glow curve was recorded at 1 °C/s to establish the position of glow peaks. There is a high intensity peak at 184 °C (labeled as peak IV) and eight secondary peaks at 48, 80, 108, 228, 288, 320, 386, and 426 °C (peaks I, II, III, and V–IX). The light-induced charge transfer between various electron traps associated with the peaks was studied. This study reveals that all peaks except the one at 228 °C (peak V) participate in the charge-transfer process. A test of the second hypothesis shows that peak V is also not reproduced by illumination (phototransfer), and the depletion of this peak does not influence the charge-transfer process. An additional study on the effect of temperature on the TL and OSL intensity was carried out to further assess the nature of the charge traps associated with the peaks. The depletion of peak V does not affect the OSL intensity. The results from both experiments are clear evidence consistent with the hypothesis that the charge trap associated with peak V is a hole trap.
X-ray sensing characteristics of a spin-coated n-ZnO film
Jigyas Das, J.M. Kalita, Ronald P. KoushikSensors and Actuators A: Physical , vol: 350 , 114142, 2023 , https://doi.org/10.1016/j.sna.2022.114142
Abstract:
We report X-ray sensing characteristics of a thick n-ZnO film. The film was synthesised using a spin-coating method from a specific solution of zinc acetate dihydrate, ethanol and triethanolamine (TEA). An X-ray diffraction analysis confirmed that the film has crystalline nature having hexagonal crystal structure. The thickness of the film was determined using a scanning electron microscope (SEM) and found to be ~29 – 45 μm. An analysis of absorption spectrum revealed the optical bandgap of the sample to be 3.45 eV. The current-voltage (I-V) characteristics were recorded under dark condition and X-ray (at 30 keV, 8 mA) illumination condition. The resistivity of the sensor under the dark condition at bias voltage 2.0 V was found to be 6.4×107 Ωcm and that under the X-ray illumination, 4.8×106 Ωcm. The sensor shows high signal-to-noise ratio within 0.5 to 6.0 V bias voltage. The analysis of response time of the sensor shows a rise time of 0.87 s and fall time of 1.08 s at 3.0 V bias voltage. The sensor is also found to be visible blind within 370 – 700 nm. A quantitative analysis of photoresponse characteristics with dose rate reveals that the sensor shows sublinear response between 0.015 and 0.220 Gy/s. The sensitivity for 0.220 Gy/s dose rate at a bias voltage of
(Invited)Nonlinear Schrödinger equation: Autonomous and nonautonomous soliton
Sudipta NandyOptik (Elsevier) , vol: 287 , 2023 , https://doi.org/10.1016/j.ijleo.2023.171035
Abstract:
This article contains a brief review of the autonomous and nonautonomous solitons supported by autonomous and nonautonomous nonlinear Schrödinger equations. Majority of the results reported here are theoretical. However, few important instances of experimental achievements have also been cited. The present review is expected to be useful and interesting to readers and young researchers.
Saturating current characteristic of 120 μm thick ZnO film and its X-ray sensing features
Jigyas Das, JM KalitaMaterials Science in Semiconductor Processing , vol: 164 , 107642, 2023 , https://doi.org/10.1016/j.mssp.2023.107642
Abstract:
We report a saturating current characteristic of a 120 μm thick ZnO film and explore its X-ray sensing features. The film was deposited using a sol-gel spin coating technique. The film has a polycrystalline nature. Measurement of current-voltage (I–V) characteristic under dark condition shows two sublinear regions from 0 to 6.0 V and 6.0–8.0 V followed by a saturation region between 8.0 and 12.0 V bias voltage. The electrical resistivity in each region is found to be ∼1.0 × 1011, 1.2 × 1011 and 1.6 × 1011 Ω cm. The I–V characteristic was further recorded under X-ray irradiation. The current under the X-ray irradiation shows a linear region from 0 to 6.0 V followed by two sublinear regions from 6.0 to 8.0 V and 8.0–12.0 V with higher magnitude than the dark current. The resistivity in each region was found to decrease by ∼101 order of magnitude under X-ray. Analysis of X-ray sensing features reveals that the signal-to-noise ratio of the device is consistent between 3.0 and 12.0 V. The rise-time and fall-time are nearly 1 s. The device shows sublinear dose rate response between 0.015 and 0.293 Gy/s with a minimum sensitivity of 28.46 ��.��−1.��−3 at 0.292 Gy/s. The device is also found to be visible-blind between 375 and 750 nm. The physical mechanism responsible for sublinear and saturating current characteristics have been explained based on retrapping and recombination of conduction electrons.
Anomalous bluish-green light emitting features of europium doped barium aluminate (BaAl2O4:Eu2+) phosphor
Manash Kalita, J.M. KalitaMaterials Today Communications , vol: 36 , 106782, 2023 , https://doi.org/10.1016/j.mtcomm.2023.106782
Abstract:
Eu doped barium aluminate is an important material for light emitting devices. Here we report structural, optical absorption and emission features of 1–5 % Eu doped barium aluminate phosphor and explore its ‘anomalous’ emission feature. The structural analysis suggests that the undoped sample has a mixture of BaAl2O4 and BaAl12O19. On the other hand, the samples doped with Eu have a mixture of BaAl2O4, Ba(Al2O4) and BaAl12O19 phases. Among these, the major phase in all the samples was BaAl2O4. The undoped sample shows a high absorption peak at around 209 nm followed by three weak intensity peaks apparent at around 250, 288 and 338 nm. In contrast, all the doped samples show three maxima at around 209, 266 and 340 nm. The position and intensity of these absorption maxima are found to vary with the Eu concentration. The optical bandgap of the undoped sample is estimated to be 5.05 eV and it is found to reduce to 4.68 eV after doping of Eu at 5 %. All the samples produce common PL emission peaks centred at ∼405, 428 and 456 nm due to potential oxygen vacancies. The doped samples show additional peaks at around 485, 518 and 657 nm due to Eu2+ and Eu3+ ions. In particular, the sample doped with 2 % of Eu produces a strong anomalous emission band of Eu2+ ion in the bluish-green region. Our study reveals that the broadband bluish-green emission of Eu2+ ions can be achieved when the barium aluminate crystal is doped by 2 % of Eu. When the host is doped by Eu at >2 % or <2 %, the emission band associated with oxygen vacancies dominates over the Eu2+ emission.
Dark-bright soliton interactions in coupled nonautonomous nonlinear Schrödinger equation with complex potentials
S Nandy and A BarthakurChaos, Solitons and Fractals , vol: 143 , 110560, 2021
Abstract:
Generalized reversible transformations and new nonautonomous higher order Nonlinear Schrödinger equation
S Nandy, Gautam K. Sahariah, A BarthakurOptik , vol: 223 , 165452, 2020
Abstract:
Pairwise three soliton interactions, soliton logic gates in coupled nonlinear Schrödinger equation with variable coefficients,
S Nandy and A BarthakurCommunications in Nonlinear Science and Numerical Simulation , vol: 69 , 370-385, 2019
Abstract:
Bilinearization of the generalized coupled nonlinear Schrödinger equation with variable coefficients and gain and dark-bright pair soliton solutions
S Chakraborty, S Nandy, A BarthakurPhysical Review E , vol: 91(2) , 023210, 2015
Abstract:
Hirota bilinearization of coupled higher-order nonlinear Schrödinger equation
S Nandy, D Sarma, A Barthakur, A BorahCommunications in Nonlinear Science and Numerical Simulation , vol: 15(11) , 3386-3389, 2010
Abstract:
Probing the electron trap-depth distribution in Sr4Al14O25:Eu2+,Dy3+
J.M. Kalita, M.L. ChithamboJournal of Luminescence , vol: 265 , 120245, 2024 , https://doi.org/10.1016/j.jlumin.2023.120245
Abstract:
Sr4Al14O25:Eu2+,Dy3+ is a superluminous persistent luminescence phosphor. Owing to its intrinsic and extrinsic point defects, it tends to luminescence incessantly after excitation, in some cases doing so for as long as 20 h. We report analysis for the energy distribution of its electron traps. The study was done using thermoluminescence (TL) measured on a sample irradiated to 2 Gy at 20 °C. A glow curve measured at 1 °C/s shows two glow peaks at 64 °C (labelled as P1) and at 252 °C (P2). The variation of intensity of peak P1 as a function of heating rate is consistent with competing radiative and non-radiative recombination processes. When the heating rate is faster than 1 °C/s, non-radiative recombinations dominate and the luminescence efficiency drops sharply beyond 70 °C. The activation energy for thermal quenching is estimated to be 0.69±0.06 eV. Once corrected for thermal quenching, the glow curves show a secondary peak (P1A) on the high temperature end of P1. The so-called Tm-Tstop method shows that peaks P1 and P2 gradually shift towards high temperature with preheating temperature Tstop. Indeed, the peak position Tm of both peaks increases with irradiation temperature Tirr. Together, these results suggest that peaks P1 and P2 are each composed of closely spaced overlapping peaks. Analysis of the fractional area between a pair of glow curves measured from the sample irradiated at different temperatures (Tirr) shows that the trap distribution associated with peak P2 is Gaussian whereas that associated with peak P1 follows a non-Gaussian distribution. The activation energy of the electron traps responsible for P1 are estimated to be in the range 0.63–0.68 eV. On the other hand, the Gaussian distribution of trap energy levels responsible for peak P2 suggests that most of the traps have an activation energy of ∼1.58 eV.
Fokas-Lenells equation dark soliton and gauge equivalent spin equation
Sudipta NandyOptical and Quantum Electronics, Springer , vol: 55 , 1-17, 2023 , https://doi.org/10.1007/s11082-023-05460-x
Abstract:
We propose the Hirota bilinearization of the Fokas–Lenells derivative nonlinear
Schrödinger equation (FLE) with a non-vanishing background. In the proposed method,
we have introduced an auxiliary function to transform the equation into bilinear form. The
use of an auxiliary function makes the method simpler than the ones reported earlier. Using
the proposed method we have obtained the dark (and bright) one soliton solution. We have
also discussed the properties of the obtained soliton and mentioned the criteria upon which
the nature of the soliton being dark or bright depends upon. Then we have obtained the
dark (and bright) two soliton solution and discussed the respective properties and also
through asymptotic analysis showed how the phase between the two individual solitons
changes before and after interaction. Eventually we have proposed the scheme for obtain-
ing N soliton solutions. The proposed method can be extended to other nonlinear equations
where straightforward bilinearization is not feasible. Later, we have introduced a gauge
transformation which transforms the spectral problem of FLE into a spectral problem for
the Landau–Lifshitz (LL) spin system. Soliton act as an information carrier and LL system
exhibits a variety of nonlinear structures so the study is worth doing.
Multi soliton solutions of the Fokas-Lenells equation using modified Bilinear method and Conservation laws
Sagardeep Talukdar, Riki Dutta, Gautam Kumar Saharia and Sudipta NandyJournal of Optics, Springer , 2023 , 10.1007/s12596-023-01523-0
Abstract:
In this paper, we propose the bilinearization of the Fokas-Lenells derivative
nonlinear Schr¨odinger equation (inshort gauged Fokas-Lenells equation) with a
vanishing boundary condition. In the proposed bilinearization we make use of
an auxiliary function to convert the trilinear equations into a set of bilinear
equations.We obtain bright 1-soliton, 2- soliton solutions and present the scheme
for obtaining N soliton solution. In the soliton solution the presence of an additional
parameter allows tuning the position of soliton. We find that the proposed
scheme of bilinearization using auxiliary function, considerably simplifies the procedure
yet generates a more general solution than the one reported earlier. We
show that the obtained soliton solution reduces to an plane wave in the limit of
infinite width. Further we show explicitly that the soliton interactions are elastic
through asymptotic analysis, that is the amplitude of each soliton remains same
before and after interaction. The mark of interaction is left behind only in the
phase of each soliton. Secondly, we propose a generalised Lax pair for the equation
and obtain the conserved densities by solving Riccati equation. We believe that
the present investigation would be useful to study the applications of the gauged
Fokas-Lenells equation in nonlinear optics and other branches of physics.
Study of blue-light emission properties of WO3:Eu microstructures
J.M. Kalita, Samasis Dev SarmaCeramics International , vol: 50 , 7067-7076, 2024 , https://doi.org/10.1016/j.ceramint.2023.12.064
Abstract:
Structural, surface morphological, optical absorption and emission properties of 0–5% Eu doped WO3 samples are studied. The samples are synthesised by acidic precipitation method. The structural analysis reveals that the sample has ‘room-temperature monoclinic’ structure. The average crystallite size of the undoped sample is ∼58.57 nm and it decreases to 34.72 nm after doping of Eu at 5%. The undoped sample has hexagonal disc-like grain structures with average diameter of ∼0.84 μm. All the samples show a sharp absorption edge above 350 nm. The transmittance of the samples increases above 400 nm and reaches its maximum at ∼490 nm. The extinction coefficient of the undoped sample is minimum at 390 nm and it has a relatively smaller value than that of the doped samples. The optical bandgap of the undoped sample is found to be 3.56 eV and it decreases to 3.28 eV with the increase of concentration of Eu to 5%. Analyses of PL spectra show that the undoped sample under 355 nm UV excitation produces a broad blue emission band with five maxima at ∼403, 414, 435, 473 and 495 nm due to band-to-band transitions and transitions involving intrinsic defects. A blue emission band centred at ∼435 nm is increased by two-fold after doping of Eu at 1%. In addition, a secondary emission band is found at ∼505 nm due to formation of an aggregate defect (F2 centre). When the doping concentration is increased to 5%, another secondary band is observed at 610 nm due to interstitial Eu3+ centre. The enhancement of the blue emission band is attributed to formation of oxygen vacancies due to substitution of W6+ ions by Eu3+ ions. The enhanced blue light in the sample doped with 1% of Eu has potential application in WLED as well as other light emitting applications.