Effect of calcium substitution on structural, dielectric, ferroelectric, piezoelectric, and energy storage properties of BaTiO3

Borkar Shilpa N.,Aggarwal Preeti,Deshpande V.K. 한국물리학회 2022 Current Applied Physics Vol.39 No.-

The effect of calcium substitution on the structural, dielectric, ferroelectric, piezoelectric, and energy storage properties of BaTiO3 (BT) ceramics has been investigated. XRD confirmed the phase formation of Barium Calcium Titanate (BCT), and structural Rietveld refinement was used to estimate the lattice parameters. It is evident from the SEM data that the average grain size decreases as calcium is added. At Curie temperature (110 ◦C), BCT 0.10 ceramic has a good dielectric constant of 15834 and a very low dielectric loss of 0.009. According to the ferroelectric and piezoelectric investigations, BCT 0.10 exhibits maximum spontaneous polarization with the highest piezoelectric charge coefficient of 100 pC/N. BCT 0.10 has a maximum energy storage density of 96.8 mJ/cm3 and a good energy storage efficiency of 53.9%, which is around three times that of pure BaTiO3. These results suggest that the BCT ceramic has good potential for energy storage applications.

Immobilization and stabilization of Pseudomonas aeruginosa SRT9 lipase on tri(4-formyl phenoxy) cyanurate

Borkar Prita,Khobragade Chandrahas,P. Venkata Ramana,Bodade Ragini,M. Swetha 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.3

Lipase was extracted and purified from Pseudomonas aeruginosa SRT9. Culture conditions were optimized and highest lipase production amounting to 147.36 U/ml was obtained after 20 h incubation. The extracellular lipase was purified on Mono QHR5/5 column, resulting in a purification factor of 98-fold with specific activity of 12307.81U/mg. Lipase was immobilized on tri (4-formyl phenoxy) cyanurate to form Schiff’s base. An immobilization yield of 85% was obtained. The native and immobilized lipases were used for catalyzing the hydrolysis of olive oil in aqueous medium. Comparative study revealed that immobilized lipase exhibited a shift in optimal pH from 6.9 (free lipase) to 7.5 and shift in optimal temperature from 55℃ to 70℃. The immobilized lipase showed 20-25% increase in thermal stability and retained 75% of its initial activity after 7 cycles. It showed good stability in organic solvents especially in 30% acetone and methanol. Enzyme activity was decreased by ~60% when incubated with 30% butanol. The kinetic studies revealed increase in K_M value from 0.043mM (native) to 0.10 mM for immobilized lipase. It showed decrease in the V_max of immobilized enzyme (142.8 μmol min^(−1) mg^(−1)), suggesting enzyme activity decrease in the course of covalent binding. The immobilized lipase retained its initial activity for more than 30 days when stored at 4 ℃ in Tris-HCl buffer pH 7.0 without any significant loss in enzyme activity.

Laser-Deposited In Situ TiC-Reinforced Nickel Matrix Composites: 3D Microstructure and Tribological Properties

Borkar, T.,Sosa, J.,Hwang, J. Y.,Scharf, T. W.,Tiley, J.,Fraser, H.,Banerjee, R. Springer Verlag 2014 JOM Vol.66 No.6

A new class of Ni-Ti-C-based metal-matrix composites has been developed using the laser-engineered net shaping (TM) process. These composites consist of an in situ formed and homogeneously distributed titanium carbide (TiC) phase reinforcing the nickel matrix. Additionally, by tailoring the Ti/C ratio in these composites, an additional graphitic phase can also be engineered into the microstructure. Serial-sectioning, followed by three-dimensional reconstruction of the microstructure in these composites, reveals homogeneously distributed primary and eutectic titanium carbide precipitates as well as a graphitic phase encompassing the primary carbides within the nickel matrix. The morphology and spatial distribution of these phases in three dimensions reveals that the eutectic carbides form a network linked by primary carbides or graphitic nodules at the nodes, which suggests interesting insights into the sequence of phase evolution. These three-phase Ni-TiC-C composites exhibit excellent tribological properties, in terms of an extremely low coefficient of friction while maintaining a relatively high hardness.

Strength versus ductility in carbon nanotube reinforced nickel matrix nanocomposites

Borkar, Tushar,Hwang, Jaewon,Hwang, Jun Yeon,Scharf, Thomas W.,Tiley, Jaimie,Hong, Soon Hyung,Banerjee, Rajarshi Cambridge University Press (Materials Research Soc 2014 Journal of materials research Vol.29 No.6

<▼1><B>Abstract</B><P/></▼1><▼2><P>Two types of carbon nanotube reinforced nickel (CNT/Ni) nanocomposites were processed, both involving spark plasma sintering (SPS) of precursor powders consisting of nickel and carbon nanotubes. The first type involved simple mechanical dry milling of nickel and CNT powders, followed by sintering using SPS, resulting in nanocomposites exhibiting a tensile yield strength of 350 MPa (about two times that of SPS processed monolithic nickel with a strength of 160 MPa) and about 30% elongation to failure. In contrast, the nanocomposites processed by SPS of powders prepared by molecular-level mixing (MLM) exhibited substantially higher tensile yield strength of 690 MPa but limited ductility with an 8% elongation to failure. While the former type of processing involving dry-milling is expected to be lower in cost as well as easy to scale-up, the latter type of processing technique involving MLM leads to a more homogeneous distribution of nanotubes, leading to extraordinarily high strength levels.</P></▼2>

해양생물 체내 잔류 미세플라스틱 조사

Shweta Borkar,Sondavid Nandanwar,김영일,김돈,심현관,김학준 한국수산과학회 2020 한국수산과학회지 Vol.53 No.2

Microplastic pollution in the marine ecosystem has been emerged as a global issue. In this study, we investigated theabundance of microplastics from clam Meretrix lusoria, blood arkshell Scapharca broughtonii, and warty sea squirtStyela clava obtained from a local market in Busan, Korea. The marine organisms were digested in 10% KOH, andwere incubated at 40˚C and 150 rpm, for 7 days. The digest was filtered through standard sieve (5 mm, 1 mm, 300μm, and 100 μm), and mciroplastics were identified using a light microscope and microFT-IR. The abundance ofmicroplastics of clam, blood arkshell, warty sea squirt was 0.08 items/g, 0.05 items/g, and 0.12 items/g, respectively. The predominant microplastic size was in the range of 100-300 μm, occupying 48%, and the predominant type wasfiber. The composition of microplastics was mostly rayon, semi-synthetic cellulosic material and polyester, which aremain component of fabric and textile. We strongly believe that this preliminary work may provide useful informationfor the establishment of the standardized analysis method of microplastics ingested by marine organisms.

Acoustic Signal based Optimal Route Selection Problem: Performance Comparison of Multi-Attribute Decision Making methods

( Prashant Borkar ),( M. V. Sarode ),( L. G. Malik ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.2

Multiple attribute for decision making including user preference will increase the complexity of route selection process. Various approaches have been proposed to solve the optimal route selection problem. In this paper, multi attribute decision making (MADM) algorithms such as Simple Additive Weighting (SAW), Weighted Product Method (WPM), Analytic Hierarchy Process (AHP) method and Total Order Preference by Similarity to the Ideal Solution (TOPSIS) methods have been proposed for acoustic signature based optimal route selection to facilitate user with better quality of service. The traffic density state conditions (very low, low, below medium, medium, above medium, high and very high) on the road segment is the occurrence and mixture weightings of traffic noise signals (Tyre, Engine, Air Turbulence, Exhaust, and Honks etc) is considered as one of the attribute in decision making process. The short-term spectral envelope features of the cumulative acoustic signals are extracted using Mel-Frequency Cepstral Coefficients (MFCC) and Adaptive Neuro-Fuzzy Classifier (ANFC) is used to model seven traffic density states. Simple point method and AHP has been used for calculation of weights of decision parameters. Numerical results show that WPM, AHP and TOPSIS provide similar performance.

Investigation of Microplastics from Three Marine Organisms

Shweta Borkar,Sondavid Nandanwar,Young-IL Kim,Don Kim,Hyun Kwan Shim,Hak Jun Kim 한국수산과학회 양식분과 2020 한국수산과학회 양식분과 학술대회 Vol.2020 No.7

Second classical Zariski topology on second spectrum of lattice modules

Pradip Girase,Vandeo Borkar,Narayan Phadatare 강원경기수학회 2020 한국수학논문집 Vol.28 No.3

Let $M$ be a lattice module over a $C$-lattice $L$. Let $Spec^{s}(M)$ be the collection of all second elements of $M$. In this paper, we consider a topology on $Spec^{s}(M)$, called the second classical Zariski topology as a generalization of concepts in modules and investigate the interplay between the algebraic properties of a lattice module $M$ and the topological properties of $Spec^{s}(M)$. We investigate this topological space from the point of view of spectral spaces. We show that $Spec^{s}(M)$ is always $T_{0}-$space and each finite irreducible closed subset of $Spec^{s}(M)$ has a generic point.

Design and Synthesis of p-hydroxybenzohydrazide Derivatives for their Antimycobacterial Activity

Bhole, Ritesh.P.,Borkar, Deepak.D.,Bhusari, Kishore.P.,Patil, Prashant.A. Korean Chemical Society 2012 대한화학회지 Vol.56 No.2

The main mycobacterial infection in human is tuberculosis caused by Mycobacterium tuberculosis. Tuberculosis is the leading infectious cause of death in the world. Therefore there is continuing and compelling need for new and improved treatment for tuberculosis. The entire logic towards design of new compounds containing 4-hydroxy-N'-(1,3-thiazoldin- 2-yldene)benzohydrazide moiety is basically for superior antimycobacterial activity. The recent advances in QSAR and computer science have provided a systematic approach to design a structure of any compound and further, the biological activity of the compound can be predicted before synthesis. The 3D-QSAR studies for the set of 4-hydroxy-N'-(1,3-thiazoldin- 2-yldene)benzohydrazide and their derivatives were carried out by using V-life MDS (3.50). The various statistical methods such as Multiple Linear Regression (MLR), Partial Least Square Regression (PLSR), Principle Component Regression(PCR) and K nearest neighbour (kNN) were used. The kNN showed good results having cross validated $r^2$ 0.9319, $r^2$ for external test set 0.8561 and standard error of estimate 0.2195. The docking studies were carried out by using Schrodinger GLIDE module which resulted in good docking score in comparison with the standard isoniazid. The designed compounds were further subjected for synthesis and biological evaluation. Antitubercular evaluation of these compounds showed that (4.a), (4.d) and (4.g) found as potent inhibitor of H37RV.

Characterization of jute fibre reinforced pine rosin modified soy protein isolate green composites

Sakhare, Karishma M.,Borkar, Shashikant P. Techno-Press 2022 Advances in materials research Vol.11 No.3

Very slow degradation of synthetic based polymers has created a severe environmental issue that increased awareness towards research in polymers of biodegradable property. Soy protein isolate (SPI) is a natural biopolymer used as matrix in green composites but it has limitations of low mechanical properties and high water sensitivity. To enhance mechanical properties and reduce water sensitivity of Jute-SPI composites, SPI was modified with pine rosin which is also a natural cross-linking agent. 30% glycerol on the weight basis of a matrix was used as a plasticizer. The fibre volume fraction was kept constant at 0.2 whereas the pine rosin in SPI ranged from 5% to 30% of the matrix. The effects of pine rosin on mechanical, thermal, water sensitivity and surface morphology have been characterized using various techniques. The mechanical properties and water absorbency were found to be optimum for 15% pine rosin in Jute-SPI composite. Therefore, Jute-SPI composite without pine rosin and with 15% pine rosin were chosen for investigation through characterization by Fourier transforms infrared spectroscopy (FTIR), Thermo-gravimetric analysis (TGA), X-Ray diffraction (XRD) and Scanning electron microscope (SEM). The surface morphology of the composite was influenced by pine rosin which is shown in the SEM image. TGA measurement showed that the thermal properties improved due to the addition of pine rosin. Antimicrobial test showed antimicrobial property in the composite occurring 15% pine rosin. The research paper concludes that the modification of SPI resin with an optimum percentage of pine rosin enhanced mechanical, thermal as well as water-resistant properties of jute fibre reinforced composites.