BITS Faculty Publications
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Item Smartchain: a smart and scalable blockchain consortium for smart grid systems(IEEE, 2019) Dua, AmitSmart grid (SG) provides a peer-to-peer energy trading mechanism wherein the electric vehicles (EVs) can trade for energy with their peers using the information and communication technologies. However, the dependence on third party for coordinating the energy trading decisions leads to a bottleneck for any distributed environment. Therefore, blockchain technology can provide a privacy-preserving and effective consensus mechanism without the control of trusted third party. Although blockchain provides inherent secure framework for transactional process, but the this security is because of computational complexity enforced. In SG environment, the conventional blockchain process could not be employed due to limited computational resources with EVs, which makes it difficult to solve the tough computational puzzles to validate the transactions. On the other hand, any compromise on the computation difficulty makes it more vulnerable to various types of attacks. Therefore, in this paper, SmartChain: a blockchain inspired smart and scalable ledger framework which does not require much computational complexity is designed for secure peer-to-peer energy trading in SG ecosystem. The proposed framework is evaluated using the parameters such as execution and validation time. The results obtained depict the superiority of SmartChain in contrast to the conventional blockchain process.Item Li+ NASICON nanocrystallites in ionic glasses: A potential nano composite system for all-solid-state Li+ ion batteries(AIP, 2019-07) Dalvi, AnshumanIn order to prepare a suitable oxide based solid electrolyte for Li+ ion batteries, Li+ NASICON LATP nanocrystallites [LiAl0.3Ti1.7(PO4)3] have been externally dispersed in fast ionic oxide glassy system, viz, 60[Li2SO4]-40[Li2O-P2O5]. To prepare this novel composite, milling assisted synthesis route was adopted in which ionic glass and LATP were separately ball milled, subsequently mixed and pelletized. The present work reports that even for a very small amount of LATP (1 wt%) in the mixture, the conductivity exhibits a significant enhancement. Structural and electrical properties of the composite with a typical composition of 1%(LATP)-99%(60LSLP) have been reported. X-ray diffraction confirmed that milling leads to reduction in the size of both the glass grains and the LATP crystallites. These novel composites have been found to be potential candidates for all solid-state battery applicationsItem Synthesis and characterization of novel electronic-ionic glass-ceramic system for cathode applications(AIP, 2020-11) Dalvi, AnshumanLi+ NASICON based mixed conducting glass-ceramic composites have been developed by mechanical milling assisted synthesis where the mixed ion conducting glass [90V2O5-10P2O5] (abbreviated as VOPO) has been externally dispersed in LiTi2(PO4)3 (LTP). The glass-ceramic with a composition 10(VOPO-0h)-90(LTP-18h) (in wt%) has been structurally and electrically characterized. XRD shows no precipitation of any crystalline phase from VOPO in resultant glass-ceramic composite. The highest total conductivity has been found to be ∼10−5 Ω−1cm−1 at 100 °C which is relatively higher than that of LTP. The total electrical transport is found to be due to the conduction of electrons and Li+ ions in the composite. Reversible cyclic voltammetry scans suggest ohmic nature of the composites. These materials have been found to be suitable as cathodes for Li+ ion battery applications.Item Electrical conductivity and thermal studies on [EMIM]BF4, Li+ and Cu2+ confined silica gel composites(AIP, 2020-11) Dalvi, Anshuman; Sivasubramanian, S.C.Ionic liquid ([EMIM]BF4), Li+ and Cu2+ confined silica gel of composition 33.3LiNO3-xCuCl2-1IL-(65.7- x)SiO2 have been prepared via sol gel route. Structural, thermal and electrical conductivity investigations have been carried out on these composites which reveal interesting results. X-ray diffraction patterns of the samples confirm their amorphous nature. TGA shows continuous water elimination from the as prepared composite. EPR spectrum shows existence of Cu2+ ions in the solid matrix at room temperature. Electrical conductivity of the composites increases with increase in the amount of CuCl2 in the composite as well as due to the increase in temperature. As these composites exhibit good ion conducting properties, they seem to have good potential as solid electrolytes in Li+ ion battery applications.Item Structural relaxation and electrical transport in NASICON reinforced Na+ ion solid polymer electrolytes(AIP, 2020-11) Dalvi, AnshumanNASICON (NaTi2(PO4)3 known as NTP) crystallites reinforcement in PEO-NaI polymer matrix leads to enhanced electrical transport. Thus, the effect of NTP ceramic filler particles on structural relaxation of polymer chains and conductivity relaxation has been studied using M′′-ω and σ′-ω spectra. Temperature dependence of dc conductivity exhibits Vogel-Fulcher-Tammann (VFT) nature for PEO-NaI and Arrhenius behavior for NTP-polymer composite films. The conductivity behavior of two samples (with and without NTP) near glass transition temperature of PEO reveals that NTP crystallites facilitate electrical transport by providing conduction pathways. Due to significant conductivity enhancement near room temperature, the composites are found to be potential candidates for all-solid-state Na+ ion battery applications.Item Electrical And Electrochemical Characterization Of ‐ Composite Polymer Electrolytes(AIP, 2011-07) Dalvi, AnshumanThe flat, thin, and flexible ion conducting polymer films were prepared by solution casting technique from PEO complexed with Structural, electrical and electrochemical properties have been studied. The samples are found to be essentially ionic in nature. The highest conductivity is found to be at for sample with 15 weight percent of in PEO matrix. cells are fabricated using polymer films as electrolytes do confirm the ionic nature. The films are found to be stable under the battery conditions.Item New generation Li+ NASICON glass-ceramics for solid state Li+ ion battery applications(AIP, 2018-04) Dalvi, AnshumanLithiumion conducting NASICON glass-ceramics have been prepared by a novel planetary ball milling assisted synthesis route. Structural, thermal and electrical investigations have been carried out on the novel composites composed of LiTi(PO4)3 (LTP) and 50[Li2SO4]-50[Li2O-P2O5] ionic glass reveal interesting results. Composites were prepared keeping the concentration of the ionic glass fixed at 20 wt%. X-ray diffraction and diffe rential thermal analysis confirm the glass-ceramic formation. Moreover, the structure of LTP remains intact during the glass -ceramic formation. Electrical conductivity of the glass-ceramic composite is found to be higher than that of the pristine glass (50LSLP) and LTP. The bulk and grain boundary conductivities of LTP exhibit improvement in composite. Owing to high ionic conductivity and thermal stability, novel glass -ceramic seems to be a promising candidate for all solid-state battery applications.Item Novel hybrid composites NaCF3SO3–PEO–NASICON for sodium ion battery applications(AIP, 2019-07) Dalvi, AnshumanNa+ ion based hybrid solid polymer electrolyte with high ionic conductivity and appreciable electrochemical stability has been reported. Addition of nano NASICON ceramic fillers [NaTi2(PO4)3] in polymer electrolyte matrix leads to significant ionic conductivity enhancement. These composites have been prepared in wide composition range and exhibit thermal stability at least upto 100°C for compositions with large amount of NASICONs. A maximum ionic conductivity of 3×10−5 Ω−1cm−1 is obtained at 40°C for a typical composition 10NaCF3SO390[0.7NTP0.3PEO]. The hybrid polymer composites are potential candidates for Na+ ion based solid-state battery applicationsItem Second order harmonic ripple reduction in DC microgrid using sliding mode control approach(IEEE, 2016) Gautam, Aditya RA single phase inverter feeding AC loads injects a substantial pulsation of the second order harmonic current (SHC) ripple at DC link. Moreover, this ripple may propagate to the DC source in the absence of the suitable controller or large size DC link capacitor. This paper proposes a SHC ripple reduction technique based on the sliding mode control for the DC microgrid application. The control technique utilizes the concept of the output impedance shaping of the DC source in order to resist the propagation of the ripple to input. A non-isolated boost converter topology has been considered as a voltage booster. This converter feeds the single phase inverter loads, and also acts as the output impedance shaping tool of the source. The proposed control technique is verified using MATLAB-simulink.Item DC bus voltage regulation in the presence of constant power load using sliding mode controlled dc-dc Bi-directional converter interfaced storage unit(IEEE, 2015) Gautam, Aditya RThe paper presents a robust sliding mode controller for a dc/dc, bidirectional converter interfacing storage unit to ensure dc bus voltage regulation in a stand-alone dc microgrid. The dc bus supplies a combination of a constant power load and conventional resistive load. In order to enhance the battery life, a state-of-charge based charging algorithm is also implemented. Depending on the measured dc bus voltage, the controller selects the appropriate operating mode of the converter. The effectiveness of the proposed controller has been validated through simulation results.