Browsing by Author "Pankaj K. Tripathi"

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In silico investigation on molecular modeling of tyramine and its deprotonated form
(Elsevier B.V., 2023) M. Kushal; S. Yadav; T. Yadav; A.K. Vishwkarma; S. Bhushan; R. Kumar; R.V. Yadav; Pankaj K. Tripathi
The present investigation covers structural, thermodynamics and vibrational spectroscopic study of tyramine neurotransmitter and its deprotonated form in the gas phase. The ab initio calculations on both the tyramine and its deprotonated form have been performed at DFT/B3LYP/6-31++G(d,p) level in order to optimize the electronic structures and computation of vibrational frequencies. Besides, the computed frequencies of tyramine and its deprotonated form have been compared with the experimentally reported IR and Raman frequencies which showed that most of the vibrational frequencies are in well agreement with earlier reported data. We have also documented the effect of hydrogen removal from the site of oxygen atom on the theoretically computed vibrational frequencies and geometrical parameters of tyramine. To explore the transition profile frontier bond orbitals energies have been computed. Moreover, natural bond orbital (NBO) calculations have also been performed to ensure stability of optimized electronic structures of tyramine and its deprotonated form. © 2023 Elsevier B.V.
Manifestation of strong magneto-electric dipolar coupling in ferromagnetic nanoparticles−FLC composite: evaluation of time-dependent memory effect
(Taylor and Francis Ltd., 2018) Tripti Vimal; Shivani Pandey; Swadesh K. Gupta; Dharmendra P. Singh; Kaushlendra Agrahari; Govind Pathak; Sumit Kumar; Pankaj K. Tripathi; Rajiv Manohar
Rod-shaped 5 wt.% copper-doped ZnO (ZnO:Cu2+) ferromagnetic nanoparticles (NPs), prepared by hydrothermal method, were dispersed in ferroelectric liquid crystal (FLC) named Felix 17/100. The effect of ferromagnetic NPs on the physical properties of FLC material (Felix 17/100) has been investigated by dielectric, electro-optical and polarising optical microscopic methods. A noteworthy time-dependent memory has been observed in the NPs-dispersed FLC composite attributed to the coupling of magnetic field associated to NPs with the director orientation of FLC. Improvement in spontaneous polarisation and dielectric susceptibility of FLC material has been ensued with the addition of ferromagnetic NPs. Faster electro-optic response, at lower applied voltage, has also been observed in NPs-dispersed FLC composite. These changes are accredited to the magneto-electric dipolar coupling existing due to the interactions between magnetic-dipole and electric-dipole moments of magnetic NPs and FLC material, respectively. The formation of periodic domains capable to show memory effect has been observed in composite. The observed time-dependent memory was confirmed by dielectric and electro-optical methods. FLC material enriched with the properties of ferromagnetic NPs can be utilised in advanced multifunctional optical devices, time-dependent memory-based security devices and computational purposes. © 2017 Informa UK Limited, trading as Taylor & Francis Group.
Superior dielectric and electrical characteristics of poly(methylmethacrylate) (PMMA)-BiFeO3-Polystyrene-2% divinyl benzene (PDB) composites
(Elsevier GmbH, 2023) N.P. Yadav; Bibhuti B. Sahu; R.N. Mahaling; Tarun Yadav; Pankaj K. Tripathi; Srikanta Moharana
An extraordinarily high dielectric constant and low dielectric loss PMMA-BFO-PDB composite material was developed by mixing poly(methylmethacrylate) (PMMA) as the polymer matrix, bismuth ferrite (BFO), and polystyrene 2% divinyl benzene (PDB) as fillers using the solution casting process. The surface morphology analysis demonstrations the PDB particle uniformly dispersed in the PMMA matrix. The frequency dependent dielectric and electrical characteristics of the PMMA-BFO-PDB composite films on various weight percentages of PDB contents and wide range of frequency at room temperature were investigated. It is observed that the maximum dielectric constant of the PMMA-BFO-PDB composites was achieved around ≈ 108 and similarly dielectric loss factor of just about ≈ 1 for 20 wt% of PDB contents at 102 Hz. In addition, the PMMA-BFO-PDB composite achieved a dielectric constant of 108 at 102 Hz, which is 21 times higher than that of the pure PMMA matrix. PMMA-BFO-PDB composite films may be used as a high performance dielectric in future energy storage devices, such as high storage capacitors. © 2023 Elsevier GmbH