IR@CGCRI - Central Glass and Ceramic Research Institute (CSIR)
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Titanium dioxide-based picoseconds pulsed fiber laser performances comparison in the 1.5-micron region
Get PDFWe demonstrated and compared picoseconds pulsed fiber lasers based on Titanium dioxide based saturable absorbers (SAs); 20 cm long Titanium dioxide-doped fiber (TiO2DF) and Titanium dioxide PVA film (TiO2PF) in the 1.5-micron region. The laser cavity utilized 2.4 m long Erbium-doped fiber (EDF) as the gain medium. A self-starting pulsed laser with a consistent repetition rate of ∼1 MHz emerged stably with the incorporation of TiO2 based SAs. The TiO2DF SA produced 9.74 ps pulsed laser at a central wavelength of 1553 nm within a pump power range of 106-142 mW. The fiber SA promoted slightly higher slope efficiency and maximum pulse energy of 13.17 and 8.56 nJ, respectively in comparison with the film SA. On the other hand, the TiO2PF SA generated stable 3.89 ps pulsed laser at an operating wavelength of 1560 nm within 86-142 mW pump power range. The film SA also produced slightly greater maximum output power of 12.17 mW and maximum peak power of 3.43 kW, respectively at the maximum pump power. The results confirmed that both TiO2 SAs can be good alternative pulse modulator in the 1.5-micron region
Prospective treatment of Parkinson's disease by a siRNA-LDH nanoconjugate
No full textIn the world, among the neurodegenerative diseases, Parkinson's is the second most common disease. Although several medications are available in the market, this disease still remains incurable and only the symptoms are controlled to a certain extent with severe side effects. For these reasons we decided to search for a novel therapeutic measure. The objective of this publication was to find a therapeutic procedure to cure this devastating disease. In this study, a biocompatible, easily permeable, cationic nanoparticle-layered double hydroxide was synthesized. Within the layers of these nanoparticles we intercalated a synuclein siRNA, which helps to silence the a synuclein gene. After the intercalation, which was optimized at a 1 : 40 ratio of siRNA: (LDH), we studied its stability in blood by a RNase protection test and serum protection assay. Both proved that LDH was an excellent nanocarrier that can protect intercalated molecules within its layers. After that, several cellular studies were performed by FACS to evaluate its biocompatibility after intercalation and cellular internalization. Results of the biocompatibility studies found it to be nontoxic and in the cellular internalization study, 51.55% of cells were taken into the nanoconjugate and confocal microscopy supported the data from FACS. Lastly, ELISA was performed to discover protein levels in the control, overexpressed, and treated groups of the SH-SY5Y cell line. These results verified that this nanoconjugate is a protective treatment procedure for Parkinson's disease
Investigation of the Brillouin effect in highly nonlinear hafnium bismuth erbium doped fiber
No full textThis paper demonstrates the generation of the Brillouin fiber laser (BFL) with 0.5 m long hafnium bismuth erbium doped fiber (HBEDF) as a hybrid gain medium. As the gain medium is pumped by a 980 nm laser diode at the power of 170 mW, a stable Stokes is observed at the output power of -2.96 dBm with Brillouin pump (BP) power of 3 dBm. The laser operates at wavelength shifted by 0.09 nm from the BP. To the best of the authors' knowledge, this is the first report of a compact BFL without employing any lengthy SMF, which features a simple cavity configuration
Wideband and flat gain series erbium doped fiber amplifier using hybrid active fiber with backward pumping distribution technique
No full textA modern wideband and flat gain erbium-doped fiber amplifier (EDFA) is suggested and accomplished, by employing a recently fabricated hafnia-bismuth-erbium doped fiber (HB-EDF) and zirconia-erbium doped fiber (Zr-EDF) as a hybrid active fiber. The performance of the proposed EDFA is examined in both forward and backward pumping schemes, using 0.5 m long HB-EDF and 4 m long Zr-EDF in series structure to fulfill a wideband amplification that cover C-and L-telecommunication bands, respectively. At the optimum laser diodes powers, the backward pumping amplifier attained a gain flatness of 14.6 dB with the maximum gain variation of +/- 1.8 dB, throughout a wide bandwidth of 70 nm, that is from 1530 nm to 1600 nm. The noise figure fluctuates from 4.3 dB to 7.9 dB within the gain flatness band. Using the backward pumping distribution technique, the proposed amplifier demonstrates not only an efficient performance, but also a cost reduction since only one laser diode is utilized to pump two stages
Regenerated grating produced in a multimaterial glass-based photosensitive fiber with an ultrahigh thermal regeneration ratio
No full textThis work demonstrates thermal regeneration of gratings inscribed in a new type of multi-material glass-based photosensitive fiber. And isothermal annealing procedure has been carried out on a type-I seed grating (SG) imprinted in erbium-doped zirconia-yttria-alumina-germanium (Er-ZYAG) silica glass-based fiber, which is initiated from room temperature of 25 degrees C up to 900 degrees C. The findings show that the created regenerated grating (RG) has an ultrahigh thermal regeneration ratio with a value of 0.72. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen
Than fire clay: characterization, beneficiation and utilization revisited
No full textThan fire clay available in Surendranagar district of Gujarat was characterized in details for its mineralogy physico-chemical characteristics and rheological properties. The crude Than clays varied widely in their characteristics and presented difficulties in manufacturing of consistent quality washed Than clay. An appropriate technique for the same has been developed and its adequacy established through laboratory and industrial trials. Washed Than clay prepared by developed technique was incorporated in a standard porcelain body in gradually increasing quantity while keeping the rational analysis of experimental bodies constant. The investigation showed washed Than clay to be 1.5 time more effective in improving dry unfired strength of he body in comparison o Bikaner clay. Its favorable effects include better rheology, lower virification temperature and reduced residual quartz in the body. However it rendered the bodies prone to high Pyroplastic deformation
Synthesis of new glassy Mg-Ca-Zn alloys with exceptionally low Young's Modulus: Exploring near eutectic compositions
No full textWe report two new magnesium-rich glassy Mg-Ca-Zn alloys of one eutectic (Mg72Ca12Zn16) and another near eutectic (Mg63Ca15Zn22) composition. The glass-forming ability of the alloys is slightly lower than that of the Mg60Ca5Zn35 alloy which has been well explored earlier. The Young's Modulus of the new glassy alloys is exceptionally low (similar to 35 GPa) and much lower than that of the Mg(60)Ca(5)Zn(35)glassy alloy (similar to 50 GPa) indicating possible potential biomedical applications. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved
Development and performance evaluation of a novel CuO/TiO2 ceramic ultrafiltration membrane for ciprofloxacin removal
No full textPharmaceutical and Personal Care Products (PPCPs) consists of diverse group of organic chemicals, which becomes a source of emerging concern, if their concentration in aqueous solution exceeds a certain limit. Ciprofloxacin, a frequently used antibiotic, gets excreted from body and its residues are found in water bodies. It is known to inhibit growth of microflora of ecosystem thereby posing great threat to environment. The present work focusses on novel approach of one step removal of ciprofloxacin from synthetic solution using nano composite ceramic ultrafiltration membrane based separation process. Copper oxide nanoparticles (CuO NP) synthesized by green route were used along with TiO2 nanoparticles (TiO2 NP) as composite to develop high flux ceramic ultrafiltration (UF) membrane over indigenously developed clay-alumina based macroporous support. The membrane was characterized in terms of X Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) to confirm about the membrane composition, field emission scanning electron microscopy (FESEM), Atomic Fluorescence Microscopy (AFM) was done to get an insight into the morphological properties, the permeation of the membrane was analyzed in terms of BET, clean water permeability, molecular weight cut-off (MWCO). FTIR analysis of membrane post filtration, suggested surface adsorption of ciprofloxacin on membrane and involvement of C=O, COO-, Ti-O-Ti and CuO groups in the process. Effect of various process parameters viz., transmembrane pressure (TMP), cross-flow velocity (CFV), operating time and feed concentration was observed on rejection efficiency of ciprofloxacin using the UF membrane. About 99.5% removal of ciprofloxacin was achieved within 60 min of operating time at 2.0 bar TMP and 2 Lmin(-1) of CFV using a feed concentration of 500 mu gL(-1) Toxicity evaluation of membrane treated permeate was carried out in algae and impact on cellular components and stress enzymes were quantified, showing reduced effect on membrane treated permeate than untreated solution. The process thus targets in remediation of such emerging organic contaminants in a cost-effective, environmental-friendly way for production of clean permeate that can be safely disposed off in the environment
Realization of phosphor-in-glass thin film on soda-lime silicate glass with low sintering temperature for high color rendering white LEDs
No full textY3Al5O12:Ce3+ phosphor-in-glass (PiG) thin film on soda-lime silicate glass substrate has been applied using screen-printing method for generation of white LED light in modern day lighting. In this work, a glass composition in a ZnO-Bi2O3-B2O3 system has been optimized to have low softening temperature, as well as matching the refractive index with that of Y3Al5O12:Ce3+ phosphor. The sintering of the PiG layers was performed at a relatively low temperature of 560 degrees C to avoid the chemical degradation of the phosphors. We employed a combination of powder x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, UV-visible absorption and fluorescence spectroscopy, as well as Fourier transfer infrared spectroscopy to study the detailed structure and different spectral properties of PiG samples. This Y3Al5O12:Ce3+-based PiG exhibits an external quantum efficiency of similar to 40%, even with its thickness of only 5 mu m. Under the excitation of the blue laser diode source, the synthesized PiG thin film has exhibited a bright white light with high color rendering index (CRI = 92 and CCT = 3877 K). The synthesized PiG sample was used to design a high-power white-light-emitting diode module by combining it with a 3 W blue LED on-board chip. This module is expected to be a promising candidate for next-generation illumination at a relatively lower cost, with long-term reliability. (C) 2019 Optical Society of Americ
Microscopic length scale of charge transport and structural properties of cobalt doped Ni-Zn ferrite nanocrystals: A structure property correlation study
No full textCobalt doped Ni-Zn ferrite nanoparticle (NZFC) were synthesized via citrate auto-ignition method to investigate the structural correlations with microscopic length scale of charge transport in system. Impedance spectroscopy revealed that both grain and grain boundary have combined effect on the conductivity relaxation process. Temperature dependent dc conductivity showed Arrhenius behavior for both grain interiors and grain boundaries. Dielectric relaxation mechanism has been elucidated via Harviliak-Negami (H.N.) formalism. Two characteristic length scales i.e. mean square displacement and spatial extent of the charge carriers inside the system were calculated via standard methods. Microstructural parameters such as bond length, bond angles, bond valence sums (BVS) etc. were estimated by Rietveld refinement of the X-Ray Diffraction (XRD) data. Changes in microstructural parameters followed the same trend as the characteristic length scales with the variation of doping content. Optimum transport properties were observed for 10 mol % of doping which were correlated with electron density plotting and BVS of different samples