IR@CGCRI - Central Glass and Ceramic Research Institute (CSIR)
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Influence of Various Physiochemical Parameters of AFeO(3) (A = Bi, Er, Ga, La, Sm, Y) Fillers on the Dielectric, Ferroelectric, Energy Storage, and Mechanical Energy Harvesting Performance of PVDF
No full textDifferent filler particles are very often used by researchers all over the world to tune the dielectric, ferroelectric, piezoelectric, energy storage, and energy harvesting properties of poly(vinylidene fluoride) (PVDF). In the present work, different perovskite ferrites, AFeO(3) (A = Bi, Er, Ga, La, Sm, and Y), are included into PVDF matrix separately. The roles of different parameters like, particle size, dielectric permittivity, ferroelectric polarization, crystal structure, etc. of the fillers in tuning the performance of respective PVDF-based composites are comprehensively and simultaneously studied here. Non-centrosymmetric fillers are found to improve the output performances of PVDF more effectively compared to that of centrosymmetric fillers. 5 wt% BiFeO3-loaded PVDF film (5BF) shows the best performance in all aspects. Upon repeated human finger tapping, the maximum instantaneous output power density and instantaneous current across a 10 M ohm resistor connected across the 5BF film are found to be approximate to 3 mu W cm(-2) and 1.25 mu A, respectively. The rectified voltage from 5BF nanogenerator is used to charge a 10 mu F commercial capacitor up to approximate to 2.8 V and lights up some LEDs as a part of its real life applicability. The fabricated nanogenerator also shows good vibration and pressure sensing ability
DEAE- Cellulose-based composite hydrogel for 3D printing application: Physicochemical, mechanical, and biological optimization
No full text3D bioprinting is a layer-by-layer additive manufacturing process that requires the incorporation of biomaterials, cells, growth factors, etc. The biomaterial-ink used in bioprinting should comprise essential properties like shear thinning, proper viscosity and reduced shear stress on cells, structural integrity, porosity, biocompatible and degradable, etc., Especially in extrusion-based bioprinting, optimization of biomaterial ink is critical. Even though single-aspect biomaterials have been used for establishing a biomaterial ink, however, they often fail to meet all properties needed to be used as a biomaterial ink. Carrying this point in view, we have formulated hydrogels using Diethylaminoethyl Cellulose (DEAE-Cellulose), Alginate (ALG), and Gelatin (GEL) as biomaterial inks. Initially, six different hydrogel formulations (F1-F6) were prepared with varying concentrations of DEAE-Cellulose (0.45%-2%), alginate (1%-2%), and keeping gelatine concentration constant at 3.33%. These for-mulations were then assayed by swelling and degradation tests. Out of six, three hydrogels (F3, F4, and F5) were eliminated after initial studies due to the rapid degradation rate. The other three hydrogels ( F1, F2, and F6) were further thoroughly analyzed by the rheological study, mechanical study, printability assay, morphological analysis, and biocompatibility assays. Here, We have demonstrated the successful formulation of three bioma-terial inks utilizing three different biopolymers for the field of tissue engineering with adequate swelling, degradation, rheological and printability properties. It was observed that the incorporation of DEAE-Cellulose significantly improved the shear thinning and viscosity recovery of hydrogels. Also, it improves mechanical integrity and printing accuracy. Moreover, all three hydrogels have shown excellent hemocompatibility and cytocompatibility. To conclude, this study proposes the optimization of composite hydrogel for 3D printing applications
In vitro and in vivo degradation assessment and preventive measures of biodegradable Mg alloys for biomedical applications
No full textMagnesium (Mg) and its alloys have been widely explored as a potential biodegradable implant material. However, the fast degradation of Mg-based alloys under physiological environment has hindered their widespread use for implant applications till date. The present review focuses on in vitro and in vivo degradation of biodegradable Mg alloys, and preventive measures for biomedical applications. Initially, the corrosion assessment approaches to predict the degradation behavior of Mg alloys are discussed along with the measures to control rapid corrosion. Furthermore, this review attempts to explore the correlation between in vitro and in vivo corrosion behavior of different Mg alloys. It was found that the corrosion depends on experimental conditions, materials and the results of different assessment procedures hardly matches with each other. It has been demonstrated the corrosion rate of magnesium can be tailored by alloying elements, surface treatments and heat treatments. Various researches also studied different biocompatible coatings such as dicalcium phosphate dihydrate (DCPD), beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HA), polycaprolactone (PCL), polylactic acid (PLA), and so on, on Mg alloys to suppress rapid degradation and examine their influence on new bone regeneration as well. This review shows the need for a standard method of corrosion assessment to predict the in vivo corrosion rate based on in vitro data, and thus reducing the in vivo experimentation
Development of Advanced Glass based Specialty Optical Fibers for Nonlinear Photonic Applications
No full textDevelopment of Semiconductor Nanomaterial based Heterostructures for Photocatalytic Applications
No full textDesign and fabrication of artificial catalytic systems to mimic natural photosynthesis which can
harvest solar energy and directly convert into usable or storable energy resources may resolve the
global energy and environment crisis. Remarkably, photocatalysis is an efficient approach to
utilize solar photons in order to drive the thermodynamic uphill reaction to generate chemical fuels
H2 and O2 by water splitting in presence of efficient photocatalyst. In this regards, Bi-based
semiconductors are focused as photocatalyst due to low cost, nontoxic, facile synthesis, interesting
optoelectronic and physicochemical properties. As single semiconductor could not meet all the
stringent requirements for water splitting under visible light, development of new functional
semiconductor based hybrid materials and understanding of interfacial band edge energetics have
been studied in this thesis work, which are useful for photocatalytic and photoelectrochemical solar
fuel H2 generation. The coupling of two materials as a semiconductor heterostructures is an
effective strategy to increase charge separation efficiency and lowering the fast electron-hole
recombination by allowing multiple active sites and thereby improve their solar light harvesting
efficiency. The conventional heterostructures of Type-II, Schottky junction, p-n junction and
advanced type direct and indirect Z-scheme heterostructures have been developed by facile methods and studied their physical, morphological, optical and electrochemical properties and finally the charge transfer mechanisms through the junction interfaces are proposed.
Therefore, the present work will be focused to introduce a stable, reusable, nontoxic, cost effective and visible light active Bi-based heterostructures as photocatalysts for the environmental remediation and renewable energy production
Incorporations of gold, silver and carbon nanomaterials to kombucha-derived bacterial cellulose: Development of antibacterial leather-like materials
No full textBacterial cellulose (BC), derived from kombucha scoby have extraordinary organoleptic properties suitable for development of leather-like materials. An improvement in physical and mechanical property is desirable for the practical applications. This work deals with the treatment of BC by incorporations of three different nanomaterials such as gold nanoparticles (AuNP), silver nanoparticles (AgNP) and graphene oxide (GO). Achieving combined benefits via synergic interactions of different nanomaterials is the major objective herein. While graphene oxide can influence some of the parameters related to mechanical properties, silver nanomaterials can offer antibacterial characteristics. Gold nano materials can bridge the BC/silver/graphene oxide as well as provide the desirable aesthetic colour. Different physical chemical and mechanical characteristics were studied in detail. For example, changes in morphology by imaging fiber network were studied using scanning electron microscopy. Fibre properties were studied by Small Angle X-Ray Scattering (SAXS) and X-Ray Diffraction (XRD). Elemental composition was studied by X-ray photoelectron spectroscopy (XPS) analysis and Raman analysis. The improvement of hydrophobicity was studied by Contact angle meter. Thermal analysis was performed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). A Picture was provided in ESI to show the modified material's leather-like appearances
Study of dry sliding wear and corrosion behavior of nanocomposite Al-Si-N coated steel
No full textThe present investigation evaluates the wear and corrosion performance of Al-Si-N coated and uncoated steel substrates. The magnetron sputtering technique was used to develop the optically transparent nanocomposite AlSi-N coating over the steel substrate. The Al-Si-N coating was the composite of a polycrystalline phase of wurtzite (hexagonal) AlN and the amorphous phase of Si3N4. The steel's surface hardness value was enhanced significantly by the Al-Si-N coating. The coated steel exhibited -19 GPa hardness value, whereas uncoated steel has -6 GPa. The wear performance testes of the coated and uncoated steels, examined by the ball on disc tribometer, marks 60% less wear of the coated steel than the uncoated steel at 2 N loads. The coated steel wear out by chipping and pull-out abrasive mechanism. The potentiodynamic polarization study indicates improved barrier property and adhesion of the coating than the passive film on the steel with a similar corrosion current value of -10 nA/cm2. The corrosion performance of the uncoated steel (SS 304) did not deteriorate with the Al-Si-N coating. Our analysis-based observations conclude that the nanocomposite Al-Si-N coating exhibits a unique combination of optically transparency, high wear, and corrosion resistance, making Al-Si-N a potential protective candidate for solar panels, optoelectronic devices, automotive shields, and optical devices
Sensitivity Analysis of Sidelobes of the Lowest Order Cladding Mode of Long Period Fiber Gratings at Turn Around Point
Get PDFA new methodology to enhance the sensitivity of a long period fiber grating sensor (LPFG) at the Turn Around Point (TAP) is here presented. The LPFG sensor has been fabricated by etching the fiber up to 20.4 mu m, until the sidelobes of dispersed LP0,2 cladding mode appeared near TAP in aqueous medium. The dual peak sensitivity of the sidelobes was found to be 16,044 nm/SRIU (surrounding refractive index units) in the RI range from 1.333 to 1.3335
Preparation of nanocrystalline Pd/SnO2 thin films deposited on alumina substrate by reactive magnetron sputtering for efficient CO gas sensing
No full textWe have prepared nanocrystalline Pd/SnO2 thin films deposited on alumina substrate by reactive magnetron sputtering for highly sensitive and selective CO gas sensing. The deposited thin films have a nanocrystalline nature and uniform granular morphologies as characterized by GIXRD and FESEM, respectively. The oxidation states and defect states were measured using XPS and PL spectra, respectively. The sensing performance of samples for CO gas was recorded at different conditions. An enhanced sensing performance of Pd/SnO2 (sensor response, SR -90.5% with fast response/recovery time -15 s/34 s) was achieved compared to pristine-SnO2 film (SR -81.7% and response/recovery time -60 s/98 s) for 91 ppm CO gas at 200 ? operating temperature. Further, Pd/SnO2 film exhibits an excellent SR -65.5% even at 100 C operating temperature. Thus, the prepared nanocrystalline Pd/SnO2 thin films can be used for the fabrication of CO gas sensors with efficient sensing performance
Tunable femtosecond nonlinear absorption and optical limiting thresholds of La2O3-B2O3 glasses by controlling the borate structural units
No full textUtilization of optical limiting materials to suppress the input intense laser energy is obligatory in a wide variety of applications that deploy the high-power laser sources. In this letter, we demonstrate that the optimization of borate structural units in lanthanum borate (LB) glasses through the addition of various concentrations of heavy metal oxides (HMOs) (PbO and Bi2O3) resulting in achievement of an optimum optical threshold value. The structural changes of these glasses were analyzed by B-11 MAS-NMR and Raman spectroscopic techniques. Nonlinear optical attributes were assessed by the Z-scan technique. The enhancement of two-photon absorption coefficient and decrement in optical limiting threshold factors suggest the LB glasses containing HMOs could be beneficial for power optical limiting devices. The achieved optical limiting threshold values of 0.075 and 0.114 J/cm(2) at 700 and 800 nm, respectively, are superior compared to advanced materials such as nanoparticles, carbon nanotubes, and few-layers of MoS2/Polymethylmethacrylates. (c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved