Faculty Publications

Now showing 1 - 4 of 4

Energy storage and management in supercapacitors for application in piezoelectric energy harvesting systems
(Sphinx Knowledge House info@sphinxsai.com, 2015) Sripad, S.; Kumar, S.; Jain, A.
Electrical double layer capacitors (supercapacitors) were fabricated using activated carbon as the active material and polyvinylidine fluoride (PVDF) as a binder with a suitable conductive additive (MWCNTs) together in an optimized ratio. The supercapacitor cells were assembled using an aqueous solution of 0.5M Na2SO4 as the electrolyte. These cells had an average capacitance of 1.7F each as measured by the constant current charging method. The two electrode symmetric cell had a specific capacitance of 23.05 F/g. The fabrication methodology has been discussed as well as the potential applications of the supercapacitor in piezoelectric element based energy harvesting systems have been elucidated. © 2015, International Journal of ChemTech Research. All rights reserved.
Capsule Network–based architectures for the segmentation of sub-retinal serous fluid in optical coherence tomography images of central serous chorioretinopathy
(Springer Science and Business Media Deutschland GmbH, 2021) Pawan, S.J.; Sankar, R.; Jain, A.; Jain, M.; Darshan, D.V.; Anoop, B.N.; Kothari, A.R.; Venkatesan, M.; Rajan, J.
Central serous chorioretinopathy (CSCR) is a chorioretinal disorder of the eye characterized by serous detachment of the neurosensory retina at the posterior pole of the eye. CSCR results from the accumulation of subretinal fluid (SRF) due to idiopathic defects at the level of the retinal pigment epithelial (RPE) that allows serous fluid from the choriocapillaris to diffuse into the subretinal space between RPE and neurosensory retinal layers. This condition is presently investigated by clinicians using invasive angiography or non-invasive optical coherence tomography (OCT) imaging. OCT images provide a representation of the fluid underlying the retina, and in the absence of automated segmentation tools, currently only a qualitative assessment of the same is used to follow the progression of the disease. Automated segmentation of the SRF can prove to be extremely useful for the assessment of progression and for the timely management of CSCR. In this paper, we adopt an existing architecture called SegCaps, which is based on the recently introduced Capsule Networks concept, for the segmentation of SRF from CSCR OCT images. Furthermore, we propose an enhancement to SegCaps, which we have termed as DRIP-Caps, that utilizes the concepts of Dilation, Residual Connections, Inception Blocks, and Capsule Pooling to address the defined problem. The proposed model outperforms the benchmark UNet architecture while reducing the number of trainable parameters by 54.21%. Moreover, it reduces the computation complexity of SegCaps by reducing the number of trainable parameters by 37.85%, with competitive performance. The experiments demonstrate the generalizability of the proposed model, as evidenced by its remarkable performance even with a limited number of training samples. [Figure not available: see fulltext.]. © 2021, International Federation for Medical and Biological Engineering.
Charge-transfer interface of insulating metal-organic frameworks with metallic conduction
(Nature Research, 2022) Sindhu, P.; Ananthram, K.S.; Jain, A.; Tarafder, K.; Ballav, N.
Downsizing materials into hetero-structured thin film configurations is an important avenue to capture various interfacial phenomena. Metallic conduction at the interfaces of insulating transition metal oxides and organic molecules are notable examples, though, it remained elusive in the domain of coordination polymers including metal-organic frameworks (MOFs). MOFs are comprised of metal centers connected to organic linkers with an extended coordination geometry and potential void space. Poor orbitals overlap often makes these crystalline solids electrical insulators. Herein, we have fabricated hetero-structured thin film of a Mott and a band insulating MOFs via layer-by-layer method. Electrical transport measurements across the thin film evidenced an interfacial metallic conduction. The origin of such an unusual observation was understood by the first-principles density functional theory calculations; specifically, Bader charge analysis revealed significant accumulation and percolation of charge across the interface. We anticipate similar interfacial effects in other rationally designed hetero-structured thin films of MOFs. © 2022, The Author(s).
Insulator-to-metal-like transition in thin films of a biological metal-organic framework
(Nature Research, 2023) Sindhu, P.; Ananthram, K.S.; Jain, A.; Tarafder, K.; Ballav, N.
Temperature-induced insulator-to-metal transitions (IMTs) where the electrical resistivity can be altered by over tens of orders of magnitude are most often accompanied by structural phase transition in the system. Here, we demonstrate an insulator-to-metal-like transition (IMLT) at 333 K in thin films of a biological metal-organic framework (bio-MOF) which was generated upon an extended coordination of the cystine (dimer of amino acid cysteine) ligand with cupric ion (spin-1/2 system) – without appreciable change in the structure. Bio-MOFs are crystalline porous solids and a subclass of conventional MOFs where physiological functionalities of bio-molecular ligands along with the structural diversity can primarily be utilized for various biomedical applications. MOFs are usually electrical insulators (so as our expectation with bio-MOFs) and can be bestowed with reasonable electrical conductivity by the design. This discovery of electronically driven IMLT opens new opportunities for bio-MOFs, to emerge as strongly correlated reticular materials with thin film device functionalities. © 2023, The Author(s).

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