IR@CGCRI - Central Glass and Ceramic Research Institute (CSIR)
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Local delivery systems of morphogens/biomolecules in orthopedic surgical challenges
No full textMusculoskeletal disorders and bone deficiencies have been established among the most important human health conditions that exist today. Because of the numerous and complex functions of bone, there are many disorders, such as osteoarthritis, rheumatoid arthritis, osteoporosis and bone cancer that arise with time. Conventional therapy alone does not always yield satisfactory results and the treatment protocol is difficult, time consuming and expensive. Systemic therapy has the disadvantages of the need for long-term treatment due to being unable to create a high local concentration and the resultant risk of toxicity in addition to problems of drug transport and cost. As a result, intensive research activity on targeted local delivery of drugs/growth factors has been initiated. Local drug delivery is potentially an advantage over standard oral/intravenous therapy/other modalities. In the present review, we have highlighted various drugs/growth factors/molecules and their potential local delivery systems for effective management of bone disorders
Influence of gamma irradiation on photoluminescence and nonlinear optical properties of Eu3+ activated heavy metal borate glasses
No full textGamma irradiation effect on absorption, photoluminescence (PL), and nonlinear optical (NLO) features of Eu3+ doped heavy metal borate glasses was studied and elucidated in detail. With blue light excitation, the emission intensity of Eu3+ doped glass was monitored with respect to irradiated dose. The PL intensity of the glasses was reduced with a raise in gamma dose rate because of the formation of colour centres. The quality of the emission colour of the pre- and post-irradiated glasses was analysed using 1931 CIE system. The Nonlinear Optical (NLO) features were examined by the Z-scan technique in the near-infrared spectral region and using femtosecond pulse excitation. The NLO attributes were enhanced with increase gamma irradiation dose. These enhancements are ascribed to the development of defects and non-bridging oxygens when irradiated with gamma radiation. The enhancement of NLO coefficients with gamma irradiation dose suggest the high dose irradiated glasses are useful for photonic device applications, particularly for optical limiters
Recent progress in 3D-printed polyaryletherketone (PAEK)-based high-performance polymeric implants for musculoskeletal reconstructions
No full textPolyaryletherketones (PAEK) have been hitherto the most promising high-performance semicrystalline thermoplastic polymers (HPPs) for several biomedical applications. These polymers make a competent replacement to implantable metals due to their biocompatibility, osteointegration properties, substantial bond strength, pliability, radiolucency and a comparable bone-like flexural modulus. Lately, additive manufacturing (AM) of customized 3D-printed patient-specific implants (PSI) using rapid prototyping techniques has been used for several surgical and medical implantations. Also, rapid technological progresses viz., fused deposition modelling and selective laser sintering in consort with enhanced imaging know-hows have streamlined the critical glitches of conventional HPPs processability with directing them to manufacture medically proficient 3D-PSI. Thus, PAEK and its polymers could not only be tailored into end-use implantable medical devices but also fit into newer AM technology-mediated biomedical arenas for other unexplored HPPs. This review summarizes the till date research on 3D-printed PAEK implant technology and its potential possibilities for their modernization and expansion in diverse musculoskeletal and soft tissue applications
Optimum Placement of Long Gauge FBG Sensor in Reinforced Concrete Bridge: A Case Study
Get PDFIn the world today, civil infrastructure plays a major role in the advancement of the modern age. They are huge in scale, complex in their behaviour and create great impact in everyday life. To ensure safety of these structures, assessment of their structural integrity is an important and challenging task. The sole purpose of structural health monitoring is to detect damage in the structures and suggest suitable rehabilitation measures. Various sensors are employed to achieve the task of damage detection and establish a warning system to avoid failure of the structures. For large structures, long-gauge Fibre Bragg Grating (FBG) sensors which are sensitive to the global behaviour, can be suitably used for this purpose. However, health monitoring of a structure with large number of sensors is expensive and hence there is a need to optimize the number of sensors deployed to minimize the cost of the exercise without compromising on performance assessment. For this purpose, several optimization algorithms are available in literature. In this study, the Effective Independence Method (EIM) which optimizes the response of the structure based on modal analysis, is used to derive the Optimum sensor placement (OSP) protocol for a reinforced concrete (RC) bridge-deck in Poland, the geometry of which has been taken from literature. This will enable the placement of 40 long gauge FBG sensors in regions for efficient damage response in the bridge-deck. Further, the optimum orientation of the sensors is further validated with a finite element model of the bridge-deck, where a moving load is applied, and strains are recorded in the sensing fibre in both longitudinal (along length) and transverse (along breadth) alignments. It has been found that long gauge FBG sensors placed in the transverse direction are more efficient in damage detection than when they are placed longitudinally
Realizing cool and warm white-LEDs based on color controllable (Sr,Ba)(2)Al3O6F:Eu2+ phosphors obtained via a microwave-assisted diffusion method
No full textGlobally, phosphor converted white-LEDs (W-LEDs) are among the most suitable sources to reduce energy consumption. Nevertheless, modernization of efficient broadband emitting phosphors is most crucial to improve the W-LED performance. Herein, we synthesized a series of novel broadband emitting Sr2-xAl3O6F:xEu(2+) phosphors via a new microwave-assisted diffusion method. Rietveld refinement of the obtained X-ray diffraction results was performed to recognize the exact crystal phase and the various cationic sites. Oxygen vacancies (V-O) formed under synthetic reducing conditions enabled Sr2Al3O6F to demonstrate bright self-activated bluish emission. Doping of Eu2+ ions unlocked the energy transfer process from the host to the activator ions, owing to which, the self-activated emission diminished and the Eu2+-doped sample showed amplified bluish-green emission. The gradual increase in Eu2+ concentrations regulated the controllable emissions from the bluish (0.34, 0.42) to the greenish (0.38, 0.43) zone under UV excitation. Because of the different absorption preferences of Eu2+ ions located at the different Sr2+ sites, Sr2-xAl3O6F:xEu(2+) exhibited bluish-white emission under blue irradiation. A further enhancement in PL intensity had been observed by the cation substitution of Ba2+ for Sr2+ sites in the optimum Sr1.95Al3O6F:0.05Eu(2+) phosphor. The as-fabricated W-LEDs utilizing the optimized Sr1.75Ba0.2Al3O6F:0.05Eu(2+) phosphor exhibited a cool-white light emission along with a 372 nm NUV-LED and a 420 nm blue-LED with a moderate CRI of 70 and a CCT above 6000 K. Such cool white emission was controlled to natural white with the CCT close to 5000 K, and the CRI above 80 via utilizing a suitable red emitting phosphor. The W-LED performances of the optimized phosphor justified its applicability to produce white light for lighting applications
Development of Mullite Based Refractory Pot for High Lead Containing Glass Melting
No full textRadiation shielding window (RSW) glass for nuclear reactor is primarily required for protecting the operating personnel from harmful radioactive rays produced during nuclear energy generation in nuclear hot cells. In this respect, the production of high lead (>70% PbO) containing RSW glass is generally made using platinum pot through bottom pouring flow casting technique. However, owing to low capacity (40 L max.) of high cost platinum pot, the production of glass slab is limited to a maximum dimension of 400x400x100 mm(3). Therefore, an alternate cost effective technology is highly required for making higher dimension glass slabs. To fulfill the requirement, low cost and higher volume refractory pot based tilt casting technology can be adopted. In this regard, the refractory pot is to be developed with adequate thermal, chemical and mechanical stabilities towards sustaining high corrosive lead oxide containing molten glass at 1100 degrees-1200 degrees C. For this purpose, a clay based alumino-silicate pot material enriched with mullite has been developed and characterized systematically. The rectangular bars have been fabricated by slip casting technique and the fabricated bars have been fired between 1450 degrees and 1550 degrees C. The fired materials have been characterized in terms of bulk density, apparent porosity, cold and hot modulus of rupture, etc. The RSW glass with more than 70% lead oxide content has successfully been melted in the pot. The quality of RSW glass produced using the pot has also been studied. In an optimized composition of the pot, the formation of higher content of mullite phase having high thermal shock and corrosion resistance with the desired mechanical stability is the key factor behind the stability of the refractory pot for making defect free RSW glass slabs. This cost effective refractory pot technology can substitute the platinum pot technology for producing larger dimension RSW glass slabs
Hydrothermal synthesis, characterization, and the influence of Bi+3 doping over nanocomposite thin films
No full textIn this study, we report ZnO and Bismuth-doped ZnO (rBi/Zn) (r = 3, 6, 9 wt%) nanoparticles through the hydrothermal synthesis method. Different characterization techniques such as XRD, TGA, FTIR, XPS, FESEM, EDX analysis, UV spectroscopy, and PL spectroscopy have been used to investigate the influence of Bi+3 doping over the synthesized rBi/Zn nanoparticles. XRD result reveals a reduction of average particle size from 30 to 21 nm with the increment of Bi+3 (3 → 9 wt%) concentration. The mass variation in rBi/Zn was found more than the pure ZnO sample which reveals in TGA results. The material rBi/Zn exhibits a single-stage to multi-stage decomposition with the enhancement of Bi+3 (3 → 9 wt%) concentration while the XPS result indicates that the reduction of binding energy with increasing Bi+3 doping. UV analysis shows that as the concentration of Bi+3 increases the band gap of the material rBi/Zn reduces from 3.217 to 2.901 eV. However, the conductivity analysis shows the enhancement in the conductivity of rBi/Zn (0 → 6 wt%) but decreases from 6 → 9 wt%. Furthermore, the morphology of rBi/Zn also changes as the doping of Bi+3 increases which is possibly due to the enhancement of lattice mismatch, and pH variation. Such a kind of rBi/Zn nanocomposite material could be used in optoelectronic devices or fiber optics-based gas-sensing applications
Architectural Glass Testing in India & Architectural Glass Research and Testing (AGRT) facility at CSIR-CGCRI, Kolkata
Get PDFArchitectural glass, a profound building material, has been in
use for an exceptionally long time. Glass being a most versatile and fully recyclable material is considered as a green and sustainable material with high durability and long life
Crystal Structure of 27R-SiAlON Synthesized Under Carbothermal Nitridation
No full textLaboratory synthesized (carbothermal-reduction-nitridation) 27R-SiAlON is studied in terms of crystallographic and microscopic features by detailed X-ray diffraction and electron microscopy experiments. 27R- SiAlON is analyzed to possess rhombohedral R3m structure and is best represented as Si1.1Al7.9O1.9N8.1. Lattice parameters, ion positions, bond lengths, angles as well as the crystallite size and strain have been determined for the constituent phase. The R3m phase in hexagonal setting exhibits enormous anisotropy with pseudo-tetragonality ratio c/a root 6 similar to 10. The electron microscopy too offers evidence of preferential growth of platelike crystals of SiAlON due to its large c-axis
Interaction between sodium dodecylsulfate (SDS) and pluronic L61 in aqueous medium: assessment of the nature and morphology of the formed mixed aggregates by NMR, EPR, SANS and FF-TEM measurements
No full textThe interaction of copolymer L61 i.e., (EO)(2)(PO)(32)(EO)(2) (where EO and PO are ethylene and propylene oxides, respectively) with surfactant SDS (sodium dodecylsulfate) in relation to their self-aggregation, dynamics and microstructures has been physicochemically studied in detail employing the Nuclear Magnetic Resonance (NMR), Electron Paramagnetic Resonance (EPR), Small-Angle Neutron Scattering (SANS), and Freeze-Fracture Transmission Electron Microscopy (FF-TEM) methods. The NMR self-diffusion study indicated a synergistic interaction between SDS and L61 forming L61-SDS mixed complex aggregates, and deuterium (H-2) NMR pointed out the nonspherical nature of these aggregates with increasing L61]. EPR spectral analysis of the motional parameters of 5-doxyl steraric acid (5-DSA) as a spin probe provided information on the microviscosity of the local environment of the L61-SDS complex aggregates. SANS probed the geometrical aspects of the SDS-L61 assemblies as a function of both L61] and SDS]. Progressive evolution of the mixed-aggregate geometries from globular to prolate ellipsoids with axial ratios ranging from 2 to 10 with increasing L61] was found. Such morphological changes were further corroborated with the results of H-2 NMR and FF-TEM measurements. The strategy of the measurements, and data analysis for a concerted conclusion have been presented