Faculty Publications

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Publications by NITK Faculty

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Author: search.filters.author.Singh, R.

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    Polymer Electrolytes and Separators for Magnesium-Ion Batteries
    (CRC Press, 2024) Singh, R.; Khalifa, M.; Janakiraman, S.; Adyam, V.; Anandhan, S.; Biswas, K.
    Magnesium (Mg)-ion-based rechargeable batteries are attractive because magnesium is bivalent, abundant, non-toxic, and inexpensive. In the development of Mg-ion batteries (MIBs) with high energy densities, their ionic conductivity and safety have become important features. The most commonly used cathodes are Mo6S8, MoO3, V2O5, MnO2, and TiO2, but they are limited due to low voltages (<2.0 V) and low specific capacities. Therefore, electrolytes are needed to improve the voltage stability and ease of synthesis. In this chapter, polymer electrolytes and separators in MIBs with liquid or gel electrolytes are briefly outlined. Polymer electrolytes are classified into two categories, namely solid polymer electrolytes and gel polymer electrolytes (GPEs). Solid polymer electrolytes have several advantages such as high safety, lightweight, and favorable mechanical properties, but their weakness is their relatively lower ionic conductivity. To overcome these issues, GPE, which is a combination of liquid electrolyte and a polymer matrix, is explored. Poly(vinylidene fluoride)-based gel electrolytes showed a high ionic conductivity of the order of 10−3 S cm−1 at room temperature. In GPEs, an electrolyte is used as an ion transport medium between the electrodes, whereas a polymer membrane acts as a separator, thereby eliminating the physical contact between the electrodes. © 2025 selection and editorial matter, Prasanth Raghavan, Akhila Das, and Jabeen Fatima M. J.
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    Dynamics of strongly coupled fluid-filled micro-cavities and PMUTs in integrated microfluidic devices
    (American Society of Mechanical Engineers (ASME) infocentral@asme.org, 2016) Dangi, A.; Singh, R.; Deshmukh, D.; Pratap, R.
    In this work, we present a novel device developed by integration of an array of Piezoelectric Micromachined Ultrasonic Transducers (PMUTs) with a microfluidic chip that can be used for characterizing the acoustical properties of the liquid present in the back-cavity of the PMUT. PMUT membrane operates in flexural mode of vibration and it is directly coupled with the cylindrical back-cavity formed during the release of the PMUT membrane. This leads to very strong structural-acoustic coupling between the PMUT and the liquid present in the its back-cavity. Presence of fluid around the thin PMUT membrane causes a significant reduction in the resonant frequencies of the PMUT due to mass loading imposed by the surrounding fluid. It also leads to the excitation of the acoustic modes of the cylindrical back-cavity when the PMUT vibrates near the fundamental acoustic frequencies of the cavity. These acoustic reverberations appear in the vibration response of the PMUT in form of additional resonant peaks. Further we explore the feasibility of capturing the acoustic signature of microbubbles introduced in the backcavity liquid. Microbubbles are generated on the microfluidic chip using flow focusing technique and introduced in the cylindrical back-cavity of the PMUT through a network of channels and wells made on PDMS and adhered to the PMUT from the backside. This approach can provide an alternative method for on-chip characterization of microbubbles. © © 2016 by ASME.
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    Estimating multiple physical parameters from speech data
    (IEEE Computer Society help@computer.org, 2016) Kalluri, S.B.; Vijayakumar, A.; Vijayasenan, D.; Singh, R.
    In this work, we explore prediction of different physical parameters from speech data. We aim to predict shoulder size and waist size of people from speech data in addition to the conventional height and weight parameters. A data-set with this information is created from 207 volunteers. A bag of words representation based on log magnitude spectrum is used as features. A support vector regression predicts the physical parameters from the bag of the words representation. The system is able to achieve a root mean square error of 6.6 cm for height estimation, 2.6cm for shoulder size, 7.1cm for waist size and 8.9 kg for weight estimation. The results of height estimation is on par with state of the art results. © 2016 IEEE.
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    Micro-Architectural support for High Availability of NoC-based MP-SoC
    (Institute of Electrical and Electronics Engineers Inc., 2019) Singh, R.; Ranga, S.V.; Patil, S.; Krishna, M.; Mehta, M.; Anoop, M.N.; Nandy, S.K.; Haldar, C.; Narayan, R.; Neumann, F.; Baufreton, P.
    In this paper, we focus on increasing the availability of Multi-Processor System on Chip (MP-SoC) for executing user applications, even when some components of the system are faulty. A Network-on-Chip (NoC) provides high bandwidth communication substrate for the multitude of components/modules in such MP-SoCs. Health of such MP-SoC, and hence its availability, is largely dependent on the health of the NoC. We consider an NoC comprising a bidirectional toroidal mesh interconnection of routers. We use a distributed built-in-self-test to identify faulty communication links. We use information so obtained to determine healthy subsystems that can be made available for executing user applications. This feature is key for enhancing availability of MP-SoCs. We realize this feature as a micro-architectural enhancement in MP-SoC that incurs an insignificant hardware overhead of less than 2%. Latency incurred for analyzing availability of MP-SoC is also insignificant. We functionally validate our proposal by emulating the system on a FPGA device and demonstrate increase in availability of the MP-SoC. © 2019 IEEE.
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    BEV-MoSeg: Segmenting Moving Objects in Bird's Eye View
    (Institute of Electrical and Electronics Engineers Inc., 2023) Sigatapu, A.K.; Satagopan, V.; Sistu, G.; Singh, R.; Narasimhadhan, A.V.
    Accurate detection of moving objects plays a vital role in motion planning and vehicle maneuvering for autonomous vehicles. Though there is a significant improvement in perception tasks like object detection and semantic segmentation by adopting Bird's Eye View (BEV) based techniques like LiftSplatShoot, SimpleBEV etc., the moving object segmentation has gained limited attention. This research addresses this gap and propose a novel end-to-end architecture that implicitly utilizes temporal cues like optical flow in BEV space by correlation or cross-attention for moving vehicle segmentation. This work also introduces custom labels to annotate moving objects in the nuScenes dataset, enhancing its utility for the BEV motion segmentation task. We achieved an Moving Vehicle IoU Score of 26% on nuScenes dataset on full six camera rig and 22% on single front camera. The code for generating these labels and the qualitative results of our model can be found in, Project page with code: https://ajayrafa25.github.io/BEV-MoSeg/ © 2023 IEEE.
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    Theoretical Investigation of BC3Monolayer for the Electrode of Na-ion Batteries
    (Institute of Electrical and Electronics Engineers Inc., 2024) Vudumula, K.; Jasil, T.K.; Yadav, A.K.; Singh, R.; Vinturaj, V.P.; Pandey, S.K.
    Recently, the Boron Carbide (BC3) material has gained more attention as the electrode of Li/Na ion batteries due to its ability to store lithium or sodium metal without ion clustering and phase separation. In this work, using the Quantum ESPRESSO tool, density functional theory (DFT) calculations were carried out to perform the structural and electrical properties of the BC3 monolayer material. The lattice parameters were optimized to achieve the minimum energy structure for further calculation of band structure, the density of states and dielectric constants in the pristine and Na-adsorbed on the 2 ∗ 2 ∗ 1 BC3 monolayer. The obtained minimum energy value is -330.302 Ry for the pristine BC3 monolayer, where as for Na- adsorbed BC3 the obtained minimum energy is -417.485. Additionally, the pristine and Na-adsorbed BC3 reveal semiconducting nature (indirect band gap 0.43 eV) and metallic nature respectively. Our study demonstrates that the BC3 monolayer has prominent potential for its application as the electrode of Na-ion batteries. © 2024 IEEE.
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    Leveraging Hybrid Modeling for Enhanced Runtime Prediction in Big Data Jobs
    (Institute of Electrical and Electronics Engineers Inc., 2024) Singh, R.; Zadokar, V.N.; Kumar, S.; Doddamani, S.S.; Bhowmik, B.
    In an era of rapid data expansion, big data has significantly transformed various industries, redefining the processes of data processing, analysis, and utilization. The widespread adoption of digital technologies has driven this surge in big data, leading to an unprecedented accumulation of information from sources such as social media, sensors, and transactions. As big data evolves, it presents significant challenges and unique opportunities, necessitating innovative solutions to leverage its potential fully. One critical challenge in big data environments is accurately predicting job runtimes, essential for optimizing resource utilization and enhancing overall system performance. Current approaches, including analytical models and machine learning algorithms, often need help to manage the complexities of unstructured data and maintain interpretability effectively. This paper proposes a novel hybrid modeling approach that integrates the strengths of both techniques to improve job runtime predictions. The hybrid architecture combines an analytical model, which captures the intricate characteristics of jobs and execution environments, with a machine learning model trained to detect patterns and relationships in historical data. As demonstrated on real-world big datasets, the hybrid model achieves greater accuracy by merging these capabilities. Utilizing the flexible capabilities of PySpark and incorporating advanced feature engineering techniques, the model dynamically adapts to various dataset sizes and complexities, ensuring robust performance across different scenarios. © 2024 IEEE.
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    An electroactive ?-phase polyvinylidene fluoride as gel polymer electrolyte for magnesium–ion battery application
    (Elsevier B.V., 2019) Singh, R.; Janakiraman, S.; Khalifa, M.; Anandhan, S.; Ghosh, S.; Adyam, A.; Biswas, K.
    The gel polymer electrolytes (GPEs) are currently interesting research area in rechargeable batteries. In the present study, synthesis and characterization of electroactive gel polymer electrolyte (EGPE) for Mg-ion batteries application have been investigated. The bead free electroactive polyvinylidene fluoride (PVDF) with high porosity is achieved by an electrospinning process. The ?-phase of PVDF is polar and electroactive with a high dipole moment. Electroactive ?-phase is confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Field emission scanning electron microscopy (FESEM) study is done to analyze the structure and morphology of the electroactive membrane. The electroactive gel polymer electrolyte is formed by immersing an electroactive PVDF membrane in 0.3 M magnesium perchlorate (MgClO4) and propylene carbonate (PC) solution. The ionic conductivity of electroactive ?-phase PVDF membrane is achieved to be 1.49 mS cm?1 at 30 °C, which is higher than commercial available polypropylene (PP) Celgard. Tortuosity of electroactive gel polymer electrolyte is found to be 1.44. The voltage stability of the EGPE is stable up to a high voltage of 5.0 V against Mg+2/Mg. The total ionic transference number and magnesium ion transference number of EGPE are also investigated to confirm high ionic conductivity. © 2019 Elsevier B.V.
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    Development of thick SiC coating on thin wall tube of zircaloy-4 using laser based directed energy deposition technique
    (Elsevier B.V., 2020) Rai, A.K.; Srinivasulu, B.; Paul, C.P.; Singh, R.; Rai, S.K.; Mishra, G.K.; Bontha, S.; Bindra, K.S.
    In the present study, optimization of various laser-processing parameters for the deposition of thick SiC coating on zircaloy-4 (Zry-4) tube is studied in view of the development of accident tolerant fuel clad material for current and future nuclear reactors with the enhanced safety. The SiC coatings are deposited using laser directed energy deposition (LDED). It is found to be quite challenging to deposit desired SiC coating on a thin (~400 ?m) substrate of Zry-4 tubes due to either its excessive melting or damage. This is minimized largely by cooling the tube from inside by passing Ar gas (20 l min?1). It is observed that different processing parameters play a vital role on homogeneity, uniformity and defects-free SiC coatings as well as on the melting and oxidation of Zry-4 substrate. A uniform and homogeneous coating of SiC is deposited on Zry-4 at the optimized laser power density of 4.52 kW cm?2, powder feed rate of 2.71 g min?1and scan speed of 325 mm min?1. The interface between SiC coatings and substrate is characterized using different techniques such as optical microscopy, scanning electron microscopy and X-ray diffraction to access the homogeneity, uniformity, defects and to identify the different phases formed in the coated layer. Coated layer is found to be consisting of Zr(?), SiC, ZrSi2, ZrSi and ZrC types of phases and the same is also confirmed by the ThermoCalc(R) based ternary phase diagram. Further, the effect of processing parameters on substrate melting and the nature of SiC coating is explained by simulating the substrate temperature using COMSOL@ multi-physics. To the author's best knowledge, this would be the first study to report the laser directed energy deposition of SiC on Zry-4 alloy. © 2020 Elsevier B.V.
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    A high thermally stable polyacrylonitrile (PAN)-based gel polymer electrolyte for rechargeable Mg-ion battery
    (Springer, 2020) Singh, R.; Janakiraman, S.; Khalifa, M.; Anandhan, S.; Ghosh, S.; Adyam, A.; Biswas, K.
    The ionic conductivity and thermal stability of the electrolyte-separator system is an essential parameter for improving battery performance and safety. The present work addresses the high thermally stable gel polymer electrolyte (GPE) using polyacrylonitrile (PAN) as a polymer membrane and magnesium perchlorate in propylene carbonate (Mg(ClO4)2-PC) as a liquid electrolyte. The PAN based polymer membrane is prepared by electrospinning process which produces a bead free and uniformly distributed nanofibers. The electrospun PAN based GPE is characterized by different physical and electrochemical techniques like X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, ionic conductivity, linear sweep voltammetry, magnesium ion transference number and electrochemical impedance spectroscopy. The ionic conductivity of PAN is 3.28 mS cm?1, compared to that of PP Celgard is 1.97 × 10–4 mS cm?1 at 30 °C. The electrochemical stability of PAN is 4.6 V and also exhibits excellent interfacial stability with magnesium metal. The results showed that the PAN-based GPE has higher ionic conductivity and thermal stability than the polypropylene (PP) Celgard membrane. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.