IR@CGCRI - Central Glass and Ceramic Research Institute (CSIR)
Not a member yet
4657 research outputs found
Sort by
Explosion induced rogue waves and chaotic multi-pulsing in a passively mode-locked all-normal dispersion fiber laser
No full textIn this work, an experimental study of non-stationary pulse dynamics consisting of explosion events and chaotic multi-pulsing from an all-normal dispersion Yb-fiber laser operating in noise-like pulse (NLP) state have been reported. During explosion in NLP state, which resembled soliton explosion, dispersive Fourier transform measurements revealed large, intermittent amplitude fluctuations in the real-time spectrum indicative of rogue waves. The fluctuations either appeared randomly at the lasing wavelength within the Yb-gain spectra or at the frequency downshifted Raman Stokes wavelength. It was also observed that such fluctuation at the Raman wavelength could even exceed the amplitude of the spectral components at the main lasing wavelength. With suitable adjustments to polarization controllers, the laser operation could be switched to chaotic multi-pulsing state where the acquisition of a large number of consecutive roundtrips revealed inter-pulse motion with unique trajectories occurring over millisecond time scales
Synthesis and magnetic properties of stable cobalt nanoparticles decorated reduced graphene oxide sheets in the aqueous medium
No full textWe have synthesized cobalt nanoparticles-reduced graphene oxide (Co-RGO) nanocomposites. The Co NPs achieve shape variation in different nanocomposites due to the strategic use of variety in the preparation techniques. The transmission electron microscope image of composites confirms the decoration of different shapes of Co NPs on RGO sheets. The magnetic study with the variation of temperature indicates a change in the form of hysteresis loops. This is due to the transition from ferromagnetic to superparamagnetic behavior. We found that cubic-shaped Co NPs while decorating RGO show the highest values for some critical magnetic parameters. Coercivity, magnetic moment, and squareness ratio are these parameters. Besides, the nanocomposite-impregnated aqueous sols are found to be quite stable and could be a potential candidate for inkjet printing and ferrofluid as the squareness ratio (M-r/M-S) is very small
A simple electrochemical approach to fabricate functionalized MWCNT-nanogold decorated PEDOT nanohybrid for simultaneous quantification of uric acid, xanthine and hypoxanthine
No full textMedical diagnostics and detection of food spoilage require estimation of hypoxanthine (HX), xanthine (XN), and uric acid (UA). A selective sensing platform has been proposed for simultaneous detection of all these species. Functionalized multi-walled carbon nanotube (fMWCNT) stabilized nanogold decorated PEDOT:TOS polymeric nanocomposite (Au-PEDOT-fMWCNT) was synthesized through rapid one-step electropolymerization to enhance conductivity and active surface area by several folds. Electrochemical activities of the proposed sensing platform were analyzed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS). Analyses through SEM, FESEM and TEM were performed to explore the surface morphology and elemental analysis of the polymeric nanohybrid was investigated by XPS, Raman, FTIR, XRD spectroscopy. Electro-catalysis of UA, XN and HX occurred at low oxidation potentials i.e. 0.082, 0.463 and 0.808 V, respectively in the optimized conditions. The uniquely designed simple, interference free Au-PEDOT-fMWCNT/GCE sensor exhibited high selectivity, good reproducibility, reusability (similar to 180 times) and stability (similar to 3 month) with excellent sensitivity of 1.73, 14.31 and 3.82 mu A mu M-1 cm(-2) for UA, XN and HX, respectively. The sensor exhibited linear ranges of detection as 0.1-800, 0.05-175 and 0.1-150 mu M with detection limits of 199.3, 24.1 and 90.5 nM for quantification of UA, XN and HX respectively. The performance of the proposed sensor was validated by addition of UA, XN and HX in human serum, urine and fish samples by comparing to those using HPLC. The results indicated good applicability of the proposed sensor for simultaneous detection of UA, XN, HX in real biological fluids. (C) 2020 Elsevier B.V. All rights reserved
Application of green synthesized ZnO nanoparticle coated ceramic ultrafiltration membrane for remediation of pharmaceutical components from synthetic water: Reusability assay of treated water on seed germination
No full textDischarges from pharmaceutical sectors into water bodies are major environmental issue as most of them are persistent in nature and causes endocrine disruption. Treatment processes presently undertaken are not effective in complete removal of these contaminants. Removal study of ibuprofen has been undertaken by adsorption and nanofiltration membrane whereas little knowledge of atenolol separation by membrane has been reported. Ceramic ultrafiltration membrane developed from green synthesized zinc oxide nanoparticles (ZnO NPs) was employed in this present study for removal of atenolol and ibuprofen drugs from synthetic solution. About 96% and 99% removal of atenolol and ibuprofen respectively was obtained by single step ultrafiltration process. OF membrane developed had surface area of 21.503 m(2)/g and pore diameter of 39.8 angstrom. X-ray diffraction study of unsupported membrane showed pure phase crystalline zinc oxide particles. The effect of different parameters viz., TMP (Transmembrane pressure), time, feed concentration etc. on membrane filtration efficiency was analyzed by RSM (Response Surface Methodology). Germination studies on Vigna mungo was performed using untreated atenolol and ibuprofen solutions and membrane treated permeate to assess the membrane efficiency of producing clean water suitable for reuse. The study revealed higher germination rate in presence of ibuprofen solution but lower germination for atenolol solution. Protein content on the other hand were highly affected in both ibuprofen and atenolol solution. Seeds germinated in membrane permeate showed better germination rate and protein content and comparable to that of control
Visible-light-induced nitrogen photofixation ability of g-C3N4 nanosheets decorated with MgO nanoparticles
No full textNitrogen fixation is a natural or artificial process, in which molecular nitrogen is combined with other elements to form more-reactive compounds containing nitrogen elements. In this study, graphitic carbon nitride nanosheets were combined with nanoparticles of MgO to fabricate an efficient binary visible-light-induced photocatalysts (abbreviated as NCN/MgO), and they were applied for the photofixation of nitrogen gas. The synthesized photocatalysts were characterized to investigate the morphology, phase structure, optical, and textural properties. The results displayed that the NCN/MgO (10%) nanocomposite has considerable performance in the nitrogen photofixation reaction compared with the pristine CN and NCN, which is 10.8 and 2.8 times, respectively. The stability of the optimum sample, as a vital characteristic of photocatalyst, was examined in three runs. Also, the effect of MgO loading, calcination temperature, solvent, electron scavenger, pH, and absence of N-2 in solution upon the NH4+ production rate was examined. Finally, an anticipated mechanism was proposed for the meaningful nitrogen photofixation enhancement. (C) 2020 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved
Nitrogen photofixation ability of g-C3N4 nanosheets/Bi2MoO6 heterojunction photocatalyst under visible-light illumination
No full textIn this study, we combined bismuth molybdate with graphitic carbon nitride nanosheets with different percentages of 10%, 20%, 30%, and 40%, in which noticeable N-2 photoreduction under visible-light illumination was seen for the binary g-C3N4 nanosheets/Bi(2)MoO(6 )photocatalysts, denoted as NCN/BMO. The XPS, HRTEM, TEM, XRD, EDX, UV-vis DRS, N-2 adsorption-desorption, FT-IR, TGA, PL, photocurrent, and EIS instruments were utilized to characterize the fabricated photocatalysts. The results displayed the construction of type-II heterojunction between the NCN and BMO components for the easy charge transfer. Under mild conditions and using ethanol as a hole scavenger, the NCN/BMO (30%) nanocomposite showed the maximum capability for ammonia generation by 3271 mu mol/L g, which is 1.9 and 9.2 times higher than the NCN and BMO components, respectively. The effects of solvent type, pH of solution, and electron scavenger on the rate of NH4 production were also studied and conversed. Finally, the stability of the NCN/BMO (30%) nanocomposite was evaluated for four cycles, in which the results were desirable. (C) 2019 Elsevier Inc. All rights reserved
X-ray photoelectron spectroscopy and ion dynamics study of W6+ doped La2Mo2O9 as SOFC electrolyte (vol 105, pg 36, 2018)
No full textFacile synthesis of doped ceria-based oxide by co-precipitation technique and performance evaluation in solid oxide fuel cell
No full textCo-precipitated nanocrystalline gadolinium (Gd)-doped ceria (CeO2) has been synthesized with varying mole ratios of Gd in CeO2 from 0.1-0.8 with intricate maintenance of solution pH. Phase pure Gd-doped CeO2 (CGO) is obtained after calcination at 750 degrees C and depending on the mole % dopant concentration, the typical crystallite size is found to vary in the range 9-27 nm. Careful observation reveals that, calcined particle size decreases with the decrease in Gd content and an optimization of the particle size with exposed (111) stable] and (100) plane reactive] happens to occur for Ce0.8Gd0.2O2-delta (CG(0.8)). High resolution transmission electron micrograph of CG(0.8) reveals highly interpenetrating lattice planes corresponding to cubic fluorite structure. The effectivity of such CG(0.8) is further supported by its high electrical conductivity of 0.02 and 0.105 S/cm @ 600 and 700 degrees C respectively. The bulk impedances exhibit ohmic (R-0) and interfacial (R-p) polarizations to be 146 and 29.96 omega cm(2) at a temperature of 600 and 700 degrees C with activation energies 0.36 and 0.8 eV respectively. The application of CG(0.8) is further established as an interlayer in nickel oxide-yittria stabilized zirconia (NiO-YSZ)/YSZ/CGO/La-Sr-Co-Fe-based single cell with a current density of 1.2 A/cm(2) @ 0.5 V and 700 degrees C using hydrogen as the fuel and oxygen as the oxidant
Degradation, wettability and surface characteristics of laser surface modified Mg-Zn-Gd-Nd alloy
No full textThis work evaluates the effects of laser surface modification on Mg-Zn-Gd-Nd alloy which is a potential biodegradable material for temporary bone implant applications. The laser surface melted (LSM) samples were investigated for microstructure, wettability, surface hardness and in vitro degradation. The microstructural study was carried out using scanning and transmission electron microscopes (SEM, TEM) and the phases present were analyzed using X-ray diffraction. The in vitro degradation behaviour was assessed in hank's balanced salt solution (HBSS) by immersion corrosion technique and the effect of LSM process parameters on the wettability was analyzed through contact angle measurements. The microstructural examination showed remarkable grain refinement as well as uniform redistribution of intermetallic phases throughout the matrix after LSM. These microstructural changes increased the hardness of LSM samples with an increase in energy density. The wetting behaviour of processed samples showed hydrophilic nature when processed at lower (12.5 and 17.5 J/mm(2)) and intermediate energy density (22.5 and 25 J/mm(2)), which can potentially improve cell-materials interaction. The corrosion rate of as cast Mg-Zn-Gd-Nd alloy decreased by 83% due to LSM. GRAPHICS]
Cooling rate effects on the structure of 45S5 bioglass: Insights from experiments and simulations
No full textDue to its ability to bond with living tissues upon dissolution, 45S5 bioglass and related compositions materials are extensively used for the replacement, regeneration, and repair of hard tissues in the human body. However, the details of its atomic structure remain debated. This is partially due to the non-equilibrium nature of glasses, as their non-crystalline structure is highly dependent on their thermal history, namely, the cooling rate used during quenching. Herein, combining molecular dynamics (MD) simulations with cooling rates ranging over several orders of magnitude and experimental studies using nuclear magnetic resonance (NMR), we investigate the structure of the nominal 45S5 bioglass composition. These results suggest that the MD simulation results when extrapolated to experimental cooling rates can provide a reasonable estimate of the structure of 45S5 bioglass. Finally, based on these results, we suggest the propensity of the phosphate group to form isolated orthophosphate species. Overall, these results reconcile the simulation and experimental results on the structure of 45S5 bioglass, and particularly on the speciation of the phosphate group, which may be key in controlling the bioactivity of 45S5 bioglass