IR@CGCRI - Central Glass and Ceramic Research Institute (CSIR)
Not a member yet
4657 research outputs found
Sort by
Optical amplification performance of erbium doped zirconia-yttria-alumina-baria silica fiber [Invited]
No full textThe suitability for optical amplification in the C + L band of a new zirconiayttria-alumina-baria silica glass fiber is evaluated. The gain and noise figure are characterized using this fiber as the gain medium. A flat gain of 25 dB with a variation of less than 3 dB in the range of 1525 to 1565 nm with a significantly low noise figure less than 4.2 dB at small signal input power, are achieved using a short length of fiber with only 1 m. The performance of the amplifier can be improved with higher pump powers and longer fiber lengths. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen
Newly developed chromium-doped fiber as a saturable absorber at 1.55-and 2.0-mu m regions for Q-switching pulses generation
No full textWe demonstrate a Q-switching operation laser at 1.55 -and 2-mu m region using a homemade 10 cm long of Chromium-doped fiber (CrDF) as a passive saturable absorber (SA). Erbium-doped fiber (EDF) and Thuliumdoped fiber (TDF) as a gain medium cooperate in the all-fiber ring cavity configuration. CrDF was fabricated by Modified Chemical Vapour Deposition (MCVD) technique in conjunction with conventional solution doping (SD) method. The CrDF has a saturable absorption of 9% at 1.55-mu m region with a saturation intensity of 22 MW/cm(2). Therefore, a stable pulse train obtainable within 75-173 mW, with a repetition rate increases from 68.12 kHz to 115.9 kHz. At the maximum pump level, a shorter pulse width, maximum output power, and maximum pulse energy are 3.85 mu s, 10.86 mW, and 94.1 nJ, respectively. In TDF laser cavity, the laser pulsing generates from 363mW to 528 mW, where the repetition rate increases from 13.02 kHz to 27.62 kHz. At maximum pump power, a shorter pulse width, maximum output power, and pulse energy are obtained with 4.48 mu s, 6.36 mW, and 230.27 nJ, respectively. Both pulse trains at 1.55- and 2-mu m region are stable with a signal-to-noise ratio (SNR) of 71 dB and 44 dB, respectively. These findings are important to the discovery of robust passive saturable absorber development in a form of fiber which has a similar melting point to the rest of the silica fiber in the proposed cavities. Thus, it will be a kick-started to alternative form of passive SAs in developing a future high-power fiber lasers
Marine organisms as a source of natural matrix for bone tissue engineering
No full textIt is a huge challenge to develop an effective regenerative approach which can be employed to restore diseased or defective part of the bone to its original anatomical and physiological function. Exploration of rich biodiversity in marine ecosystem is one of the most exciting prospects for development of biomaterial for bone tissue engineering. Due to their organic nature, the materials which are fabricated from natural environment are usually safe, biocompatible, biodegradable and osteoconductive which stimulates osteogenesis. Furthermore, marine derived biomaterials are superior to the current available materials which are employed for either in vitro or in vivo grafts or scaffolds as there are some limitations with the present strategies. Regardless of their immense potential, the natural marine resources are enormously unexploited. This review recounts various biomaterials which can be extracted from marine organism for future medical application
Interaction of Thulium Fiber Laser with Urinary Stone: Effect of Laser Parameter on Fragmented Particle Size and Retropulsion
No full textSingle-mode thulium fiber laser (TFL) at 1.94 mu m with optimal energy and pulse settings has potential benefits for lithotripsy over the presently used Ho:YAG laser. A fiber Bragg grating-based, all-fiber, continuous-wave and modulated TFL at 1.94 mu m is configured to deliver up to 30 W of laser power with efficiency of 50%. The TFL operating in the range of repetition rate 10 Hz-1 kHz and corresponding pulse energy 2 J-1.05 mJ is irradiated on urinary stone for in-vitro evaluation of fragmented particle size and retropulsion. TFL irradiation at higher repetition rate fragments the stones into smaller particle size (average size of few hundreds microns) resulting reduced retropulsion
Effect of Forging on Microstructure, Mechanical Properties and Acoustic Emission Characteristics of Al Alloy (2014): 10 wt.% SiCp Composite
No full textIn this paper a systematic study has been undertaken to study the effect of forging on microstructure, mechanical properties and acoustic emission (AE) characteristics of Al alloy (2014)10 wt.% SiC metal-matrix composites. Hammer forging was carried out at a temperature of 470 degrees C in an open die, with a deformation ratio of 3.5:1. Microstructural analyses were carried out at three different positions of forged billet. Significant material flow was observed in the sample taken from the sides of the forged billet, but no appreciable material flow was observed at the center of the forged billet. The microstructural characterization showed that forging resulted in cracking of SiC particles in Al alloy (2014)-10 wt.% SiC composite. The AE results during forging showed an increase in AE signal intensity during the initial yielding period and a subsequent decrease in the intensity of AE signals with sudden burst at the end of the forging. The plastic deformation at room temperature was less ductile in nature but at high temperature, appreciable ductility was observed. The FESEM micrographs of fracture surfaces of the tensile specimens showed appreciable clustering of SiC particles during plastic deformation both at room and high temperature
Shape-dependent magnetoelectric coupling in nanoscale BiFeO3
No full textThe nanorods and nanocuboids of multiferroic BiFeO3 exhibit remarkable shape dependence of crystallographic, ferroelectric, and magnetoelectric properties. The nanorods, for example, assume R3m space group (as against R3c observed both in bulk and nearly spherical nanosized particles) and are found to be oriented preferentially with long axis parallel to 101]. The magnetic and electric coercive fields as well as magnetoelectric coupling - measured from change in remanent polarization under a magnetic field - are found to be larger in nanocuboids. The shape dependence of multiferroic properties originates from that of microstrain and anisotropy. (C) 2018 Elsevier B.V. All rights reserved
Soft-template synthesis of high surface area mesoporous titanium dioxide for dye-sensitized solar cells
No full textIn the present work, 10 to 14 nm titania nanoparticles with high-packing density are synthesized by the soft-template method using a range of cationic surfactants including cetyl trimethylammonium bromide (CTAB), Sodium dodecyl sulfate (SDS), and dodecyl trimethylammonium bromide (DTAB). The synthesized nanoparticles are used as a photoanode material in dye solar cells. Density functional theory (DFT) simulations reproduce our experimental results of charge transfer and strong interaction between the TiO2 and N719. N719-TiO2 complex establishes strong electrostatic bonding through H of the dye with the O of TiO2 surface. Solar cell efficiency of 6.08% with 12.63 mA/cm(2), 793 mV, and 48.5% for short circuit current density, open circuit voltage, and fill factor, respectively, are obtained under 1 sun illumination for the dye-sensitized solar cell (DSSC) using a film of mesoporous TiO2 synthesized from the SDS surfactant. On the other hand, the 21 nm commercial TiO2 powder (P25) device results in 4.60% efficiency under similar conditions. Electrochemical impedance spectroscopic studies show that the SDS device has lesser charge transport resistance than the other devices because of its higher surface area, packing density, and dye loading capacity. Our results show that employing high packing density-based TiO2 nanoparticles represents a commercially viable approach for highly beneficial photoanode development for future DSSC applications
Wide-band flat-gain optical amplifier using Hafnia and zirconia erbium co-doped fibres in double-pass parallel configuration
No full textA new compact and wide-band erbium-doped fibre amplifier (EDFA) was demonstrated by combining Hafnia-bismuth Erbium co-doped fibre (HB-EDF) and zirconia-yttria-aluminum Erbium co-doped fibre (Zr-EDF) as a hybrid gain medium, in parallel double-pass configuration. The proposed amplifier comprises a 0.5 m long HB-EDF and 4 m long Zr-EDF optimized for C- and L-band operations, respectively. The HB-EDF and Zr-EDF has erbium ion concentration of 12,500 ppm and 2800 ppm, respectively. At -10 dBm input signal, a wide-band flat gain of 15.7 dB is achieved with gain fluctuation of less than 1.5 dB within a wavelength region from 1525 to 1600 nm. Compared to same configuration of HB-EDF and Zr-EDF amplifiers which are using two pieces of HB-EDF and Zr-EDF, respectively with the same total amount of erbium ions, the proposed EDFA with hybrid gain medium provides even better performances in term of flat gain, bandwidth and noise figure
Preparation, Characterization and Properties of Newly Synthesized SnO2-Polycarbazole Nanocomposite via Room Temperature Solution Phase Synthesis Process
No full textThe introduction of inorganic metal oxide nanoparticles in a polymer matrix is found to significantly modulate its optical, electrical and electrochemical properties. Here, we report the one-pot synthesis of SnO2-polycarbazole (PCz) nano composite via solution phase technique (in situ chemical oxidative polymerization route) for the first time. The morphological and compositional analyses of these organic-inorganic hybrid nano composites were done by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), the Fourier transform infrared (FTIR) spectroscopy and ultraviolet-visible (UV-visible) spectroscopy. The successful loading of SnO2 nanoparticles by PCz was apparent from FESEM micrographs. UV-Visible spectroscopy revealed that optical property of the pristine PCz was significantly revamped after incorporation of SnO2 nanoparticles. The Synergetic interactions between polycarbazole and tin oxide nanoparticles were apparent from the FTIR and XRD spectra. Thermal stability of the material estimated by Thermo gravimetric (TGA) analysis; which shows thermal strength is significantly increased after incorporation of SnO2 nanoparticles in the PCz matrix. The I-V curve shows good ohmic contact of the material with tin electrode and electrical conductivity of the material is significantly altered with varying the loading percentage of SnO2 nano particles in PCz matrix. (C) 2019 Published by Elsevier Ltd
Photocatalytic hydrogen generation using gold decorated BiFeO3 heterostructures as an efficient catalyst under visible light irradiation
No full textPerovskites based oxides materials with a suitable energy level have been considered as efficient photocatalysts
for solar hydrogen generation. Gold nanoparticles (Au NPs)-sensitized BiFeO3 (BFO) perovskite heterostructures
was synthesized, characterized and tested for hydrogen generation under visible light (λ > 420 nm) irradiation.
Au/BFO heterostructures was synthesized using a facile hydrothermal method followed by radiolysis without
using any surfactant or strong reducing agent. The shape-dependent photocatalysis revealed that the BFO octahedron
(BFO-Oct) exhibited higher hydrogen generation (1.4 mmol h–1 g–1) than the BFO nanosheets (BFO-Ns)(1.1 mmol h–1 g–1) and BFO cylindrical shaped (BFO-Cyl) (0.5 mmol h–1 g–1). After radiolytic construction of the Au/BFO heterostructure, more efficient hydrogen generation was obtained due to the photoinduced electron transfer. The photoresponse of the Au/BFO heterostructures was also assessed in terms of the photocurrent via photoelectrochemical (PEC) measurement which showed Au/BFO-Ns generated higher photocurrents than BFONs by a factor of ∼3.8. The Nyquist plot demonstrated facile charge transfer of BFO-Ns after formation of
heterojunction with Au NPs. The Mott–Schottky plot revealed that catalysts are n-type and photo generated charge carrier concentration has been increased for Au/BFO heterostructures (0.92×1017 cm−3) compared to pure BFO (0.47×1017 cm−3). On the basis of experimental results, the enhanced photocatalytic activities of Au/BFO heterostructures could be ascribed to the significant visible light absorption and the efficient charge carrier separation. This study offers a new route to design noble metal modified perovskites based heterostructure as photocatalysts for water splitting