Faculty Publications

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Statistical optimization of melt-quenching process parameters for multiple properties of ternary barium phosphate glasses
(Elsevier Ltd, 2015) Narayanan, M.K.; Shashikala, H.D.; Manjaiah, M.
In the present work simultaneous optimization of density, refractive index and hardness (multiple performance characteristics) of ternary barium phosphate glasses has been carried out using Taguchi based grey relational analysis. Effect of the parameters such as CaF2 content, melting temperature and melting time on the response parameters of (50 - X)BaO-XCaF2-50P2O5 (X = 0, 10, 20 mol%) glasses prepared according to the experimental layout of Taguchi's standard orthogonal array has been studied. Highest grey relational grade is the performance criteria used in this study to indicate the optimum level of process parameters needed for the best multiple performance characteristics. Analysis of variance (ANOVA) conducted on grey relational grade shows that under 95% confidence level, CaF2 content is the only parameter significantly affecting multiple performance characteristics. Experimental values of response parameters obtained by conducting the confirmatory experiment at optimum level of process parameters are closer to the optimal set of predicted values. © 2014 Elsevier B.V. All rights reserved.
Thermal and optical properties of BaO-CaF2-P2O5 glasses
(Elsevier B.V., 2015) Narayanan, M.K.; Shashikala, H.D.
Thermal and optical properties of ternary phosphate glasses prepared by conventional melt-quenching technique, belonging to the series (50 - X)BaO-XCaF2-50P2O5 (X = 0 to 10 mol%) were investigated with increase in CaF2 content. Thermal stability and glass forming ability studied using differential thermal analysis (DTA) were found to increase with the increase in CaF2 content. Powder X-ray diffraction (XRD) analysis of heat treated samples also revealed that CaF2 addition improves the thermal stability against crystallization. Increase in both glass transition temperature and onset crystallization temperature with the increase in CaF2 content can be attributed to the partial substitution of Ba2 + ion with Ca2 + ion, which is having larger field strength. The observed decrease in the melting temperature of glass batch with the increase in CaF2 content indicates that CaF2 acts as a flux and reduces the viscosity of the glass melt. The decrease in refractive index of the glasses with the increase in CaF2 content can be attributed to replacement of lower field strength Ba2 + by Ca2 + or the partial substitution of more polarizable oxygen ion by fluorine. Optical band gap energy slightly increased and Urbach energy marginally reduced with the increase in CaF2 content. Increase in optical band gap energy was further confirmed by calculating theoretical optical basicity of glasses. Average anion polarizability (?O/F) of (50 - X)BaO-XCaF2-50P2O5 glasses calculated from refractivity data using Lorentz-Lorentz relation was correlated with its theoretical optical basicity (?th) using the previously established correlation for oxyfluoro phosphate glasses. © 2015 Elsevier B.V. All rights reserved.
Optimization and analysis of process parameters of melt quenching technique for multiple performances of rare earth doped barium borate glass synthesis using Taguchi's design and grey relational approach
(Elsevier B.V., 2023) Ingle, A.I.; Shashikala, H.D.; Narayanan, M.K.; Dubeto, M.T.; Gupta, S.
Glass materials with strong physical, structural, and optical properties are in high demand in today's social and industrial sectors. Researchers have recently established the extensive uses of these widely utilized glassy materials in optoelectronic devices, aerospace, nuclear industries, etc. Optimization usually plays a significant role in the synthesis of material. Hence, this article uses the statistical optimization of multiple process parameters of the melt quenching technique for rare earth doped barium borate glass 60B2O3-(40-X)BaO-XMO (MO-Er2O3/CeO2 and X = 0.5,1.0,1.5 mol percentage)by Taguchi's Design of Experiment. The multiple performance characteristics were studied using Grey relational analysis. An experimental format for preparing the Barium Borate glass was utilized with a standard L9 orthogonal array designed by Taguchi. Grey relational analysis was used to analyze the effects of processing parameters, including melting temperature, the composition of rare-earth oxide, and melting time of glasses on density, refractive index, and indirect bandgap. Analysis of variance (ANOVA) showed the influence of process parameters on the multiple response parameters as directed by the S/N ratio of the response parameter. The prediction of optimal conditions for contributing process parameters to the multiple response parameters was estimated efficiently. Additionally, as compared to the initial conditions, the optimal confirmatory experiment exhibited a considerable improvement in the response parameters (refractive index, density, and indirect bandgap). Grey relational grade and analysis of variance (ANOVA) revealed that melting temperature to be sole factor significantly affecting multiple responses with a 95% confidence level. The objective of the work is to optimize the melt quenching process parameters and their influence on the physical and optical properties of glass for photonic applications. Using this optimization method, melt quenching was found to be the most influential parameter contributing about 73–74% in tuning the desired response parameters. The findings also revealed a very less deviation between the statistically predicted and experimental data of response parameter, with deviation ranging from 0.37 to 2.14%. This good agreement between experimental and predicted values of response parameters indicated the suitability of Taguchi method of optimization for melt quenching technique. © 2022 The Authors

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