Dynamic high‐temperature crystallization and processing properties of industrial soda–lime–silica glasses

In situ dynamic crystallization properties of industrial soda–lime–silica glasses at realistic processing temperatures have not yet been explored. Hence, we collected in situ high‐temperature X‐ray diffraction patterns for 10 different industrially manufactured soda–lime–silica glasses as a function of temperature between 900 and 1200°C to investigate the phase relations in their devitrified melts. The high‐temperature X‐ray diffraction study was complemented by measuring the liquidus temperature of those glasses by the temperature gradient technique. A multiple variable regression analysis was applied to the experimental and modeled data to produce a predictive model for the rate of solidification and liquidus temperature based on glass composition. We have demonstrated that forms of quartz (SiO2) and Na2CaSiO4, which are not traditionally identified by room temperature X‐ray diffraction studies of commercial soda–lime–silica glasses, are the dominant crystalline phases at 800 and 900°C. Upon further heating, different forms of cristobalite become the primary phase field prior to the formation of X‐ray amorphous melts, irrespective of the glass composition. Sporadic unidentified as well as high‐temperature stable SiO2 polymorphs that are not recoverable to room temperature were also observed. In contrast to the literature, wollastonite (CaSiO3) and devitrite (Na2Ca3Si6O16), which are the main predictor variables in previously developed liquidus temperature models, were not observed prior to the formation of X‐ray amorphous glass melts, and hence their influence on liquidus temperature may be questionable. It was also found that the difference between glass processing and liquidus temperatures can be excessively high, and such large temperature differences can potentially be exploited and reduced to enable decreases in melting or processing temperatures of industrial soda–lime–silica glass melts

X-Ray fluorescence analysis of feldspars and silicate glass: effects of melting time on fused bead consistency and volatilisation

Reproducible preparation of lithium tetraborate fused beads for XRF analysis of glass and mineral samples is of paramount importance for analytical repeatability. However, as with all glass melting processes, losses due to volatilization must be taken into account and their effects are not negligible. Here the effects of fused bead melting time have been studied for four Certified Reference Materials (CRM’s-three feldspars, one silicate glass), in terms of their effects on analytical variability and volatilization losses arising from fused bead preparation. At melting temperatures of 1065 °C, and for feldspar samples, fused bead melting times shorter than approximately 25 minutes generally gave rise to greater deviation of XRF-analyzed composition from certified composition. This variation might be due to incomplete fusion and / or fused bead inhomogeneity but further research is needed. In contrast, the shortest fused bead melting time for the silicate glass CRM gave an XRF-analyzed composition closer to the certified values than longer melting times. This may suggest a faster rate of glass-in-glass dissolution and homogenization during fused bead preparation. For all samples, longer melting times gave rise to greater volatilization losses (including sulphates and halides) during fusion. This was demonstrated by a linear relationship between SO3 mass loss and time1/2, as predicted by a simple diffusion-based model. Iodine volatilization displays a more complex relationship, suggestive of diffusion plus additional mechanisms. This conclusion may have implications for vitrification of iodine-bearing radioactive wastes. Our research demonstrates that the nature of the sample material impacts on the most appropriate fusion times. For feldspars no less than ~25 min and no more than ~60 min of fusion at 1065 °C, using Li2B4O7 as the fusion medium and in the context of feldspar samples and the automatic fusion equipment used here, strikes an acceptable (albeit non-ideal) balance between the competing factors of fused bead quality, analytical consistency and mitigating volatilization losses. Conversely, for the silicate glass sample, shorter fusion times of less than ~30 minutes under the same conditions provided more accurate analyses whilst limiting volatile losses

A survey of commercial soda–lime–silica glass compositions: Trends and opportunities II—Principal component analysis (PCA) of glass compositions

In the first part of the study, we sampled and investigated the composition of commercial glasses in the UK market from 2022 to 2023, as well as property data provided by various models. In this part, we utilize principal component analysis (PCA) to conduct a comparative analysis, integrating these data with the composition of commercial glass documented in previous literature. The widely held belief that the composition of commercial soda–lime–silica glasses has remained essentially unchanged over the past 30+ years is challenged by this research. The differences in composition of current commercial glass compositions compared to glasses from 30 to 40 years ago have been quantified. This not only sheds light on the direction of travel and reasons for adjustments to UK glass compositions over recent decades, but it also provides insights and predictions into the future trends

X-ray Fluorescence Analysis of Feldspars and Silicate Glass: Effects of Melting Time on Fused Bead Consistency and Volatilisation

Reproducible preparation of lithium tetraborate fused beads for XRF analysis of glass and mineral samples is of paramount importance for analytical repeatability. However, as with all glass melting processes, losses due to volatilisation must be taken into account and their effects are not negligible. Here the effects of fused bead melting time have been studied for four Certified Reference Materials (CRM’s: three feldspars, one silicate glass), in terms of their effects on analytical variability and volatilisation losses arising from fused bead preparation. At melting temperatures of 1065 °C, and for feldspar samples, fused bead melting times shorter than approximately 25 min generally gave rise to a greater deviation of the XRF-analysed composition from the certified composition. This variation might be due to incomplete fusion and/or fused bead inhomogeneity but further research is needed. In contrast, the shortest fused bead melting time for the silicate glass CRM gave an XRF-analysed composition closer to the certified values than longer melting times. This may suggest a faster rate of glass-in-glass dissolution and homogenization during fused bead preparation. For all samples, longer melting times gave rise to greater volatilisation losses (including sulphates and halides) during fusion. This was demonstrated by a linear relationship between SO3 mass loss and time1/2, as predicted by a simple diffusion-based model. Iodine volatilisation displays a more complex relationship, suggestive of diffusion plus additional mechanisms. This conclusion may have implications for vitrification of iodine-bearing radioactive wastes. Our research demonstrates that the nature of the sample material impacts on the most appropriate fusion times. For feldspars no less than ~25 min and no more than ~60 min of fusion at 1065 °C, using Li2B4O7 as the fusion medium and in the context of feldspar samples and the automatic fusion equipment used here, strikes an acceptable (albeit non-ideal) balance between the competing factors of fused bead quality, analytical consistency and mitigating volatilisation losses. Conversely, for the silicate glass sample, shorter fusion times of less than ~30 min under the same conditions provided more accurate analyses whilst limiting volatile losses

Mechanical and structural properties of soda lime silica glasses as a function of composition.

Significant changes in mechanical and structural properties can be obtained by modifying commercial soda-lime-silica glass composition within a narrow range; and this can potentially enable the glass scientists and technologists to produce commercially viable, stronger and lighter soda-lime-silica glass products. In this research, four different series of soda-lime-silica glasses have been produced; MgO and CaO glass series are fabricated by varying the magnesia/silica and calcia/silica ratios respectively; and CaO-MgO and Al2O3 glass series were produced by altering the calcia/magnesia and (alumina + soda)/silica ratios, respectively. Mechanical properties such as Vicker’s hardness and fracture toughness were measured by indentation method; and bending fracture toughness was also obtained by the surface crack in flexure method. Differential thermal analysis was used to determine the glass transition temperatures of these glass series. The variation of mechanical properties of glass series have been interpreted in terms of acquired structural information from 29Si NMR, Raman and FTIR absorption spectroscopies. It is found that magnesia and calcia act as network modifiers when they are substituted for silica in MgO and CaO glass series, and therefore they reduce connectivity of glass series. However, at fixed silica and soda contents, addition of magnesia at the expense of calcia increases network polymerisation. Indentation experiments showed that magnesia rich soda-lime-silica glasses are more susceptible to stress-corrosion than calcia rich glasses, and that they exhibit large discrepancies between direct and 24 hour indentation toughness values. Raman spectra of MgO and CaO-MgO glass series show that the intensity reduction in the long tail of the low frequency band is less for magnesia rich soda-lime-silica glasses compared to the observed reduction in calcia rich ones, and presumably this is potentially linked to presence of relatively larger membered rings in magnesia rich glasses. And therefore, the potential higher abundance of large membered rings might reduce stress-corrosion resistance of high magnesia containing glasses. No significant trend between bending fracture toughness and indentation fracture toughness could be identified. Moreover, large discrepancies are observed between direct and 24 hours indentation toughness values of MgO glass series. And all these inconsistencies raise the doubts over the accuracy of indentation method which has also been discussed in the literature. Elastic moduli have been measured by acoustic means, and it was found that Young’s moduli of MgO, CaO, CaO-MgO and Al2O3 glass series increase with network depolymerisation; and the significant role of packing density on Young’s modulus and Poisson’s ratio is obtained. Bending (surface crack in flexure) experiment has been used to minimise the uncertainties associated with indentation method. Contrary to the reports of previous works, the addition of magnesia in place of calcia does not increase fracture toughness. However, substitution of calcia in place of silica or magnesia gives rise to higher fracture toughness values in CaO and CaO-MgO glass series. It was also found that the replacement of alumina by silica can increase fracture toughness of soda-lime-silica glasses, and this increment in fracture toughness can be attributed to reduced stiffness and easier plastic deformation of silicate backbone as a result of removal of alumina that have significantly larger bond strength than that of other conventional oxides used in soda-lime-silica glasses. Furthermore, glasses that are more resilient to sharp contact loading exhibit lower fracture toughness values; whereas, glasses that possess larger packing densities and Poisson’s ratios favour easier shear flow and show larger fracture toughness values. Therefore, increasing alkaline earth oxide content preferably using a less covalent one in place of silica; or removing structural units (i.e. AlO4) that have very high dissociation energy per unit volume from silicate network can reduce stiffness of backbone of silicate glass and hence can increase plastic deformation capacity and bending fracture toughness of soda-lime-silica glasses. Calcium oxide-rich glasses (i.e. 14CaO glass) exhibit one of the highest fracture toughness values (~0.95 MN m-3/2) whilst the lower fracture toughness values (~0.78 MN m-3/2) are observed for low calcium oxide containing silicate glasses; and the total increment of fracture toughness is ~ 22% due to the replacement of silicon dioxide by calcium oxide. This significant improvement in the fracture toughness with composition can enable to formulate new glass compositions to produce thin-walled and tougher soda-lime-silica glass products such as container glass (i.e. bottles and jars) in glass manufacturing industry. Additionally, addition of calcium oxide in place of silicon dioxide can also reduce melting temperature of the glass batch. Consequently, higher calcium oxide/silicon dioxide ratio in soda-lime-silica glass can be more beneficial for glass industry to manufacture lighter and energy-efficient glass products. Higher fracture toughness values are generally observed for calcium oxide-rich soda-lime-silica glasses that are more packed than silicon dioxide-rich glasses, and this shows that denser soda-lime-silica glasses exhibit higher fracture toughness values. However, it can be possible to produce tougher soda-lime-silica glasses that have larger network openness and relatively lower density as is obtained in Al2O3-free glass; but energy consumption will be significantly higher for these high silica containing soda-lime-silica glasses, although these glasses exhibit good chemical durability. Overall, market competitiveness and high energy costs in glass industry can dictate the use of cost-effective glass compositions such as calcium rich soda-lime-silica glasses

A survey of commercial soda–lime–silica glass compositions: Trends and opportunities. I—Compositions, properties and theoretical energy requirements

This research aimed to investigate the compositions of commercial soda–lime–silica glasses currently present in the UK market, as there is a lack of recent research on the subject, with the most recent studies now being over 20 years old. This study involved sampling and analyzing the compositions of over 30 commercial soda–lime–silica container and float glass samples, primarily from the UK market, in 2022 to 2023. Based on the results, the characteristics of these commercial glasses has been evaluated using multiple property models and analysis methods. In the first part, we illustrated the opportunities for glass manufacturers to modify or adjust their glass compositions to enable lower melting temperatures, thereby reducing energy demand and fuel carbon emissions. This can help the glass industry meet its net zero carbon emissions targets. It de‐risks compositional modifications for a glass manufacturer by highlighting that other manufacturers have already successfully commercially implemented such changes

Sugammadex improves neuromuscular function in patients receiving perioperative steroids

Context: Sugammadex has steroid‑encapsulating effect.Aim: This study was undertaken to assess whether the clinical efficacy of sugammadex was altered by the administration of steroids.Setting and Design: Sixty patients between 18 and 60 years of age with the American Society of Anesthesiologists I–IV and undergoing elective direct laryngoscopy/biopsy were included in this study.Materials and Methods: Patients were assigned to two groups based on the intraoperative steroid use: those who received steroid (Group S) and who did not (Group C). After standard general anesthesia, patients were monitored with the train of four (TOF) monitoring. The preferred steroid and its dose, timing of steroid administration, and TOF value before and after sugammadex as well as the time to recovery (TOF of 0.9) were recorded.Statistical Analysis Used: SPSS software version 17.0 was used for statistical analysis.Results: There is no statistically significant difference between groups in terms of age, gender, preoperative medication use, and TOF ratio just before administering sugammadex. The reached time to TOF 0.9 after sugammadex administration was significantly shorter in Group S than Group C (P < 0.05). A within‑group comparison in Group S showed no difference in TOF ratio immediately before sugammadex as well as the dose of sugammadex in those who received prednisolone; time to TOF 0.9 was higher in prednisolone receivers as compared to dexamethasone receivers (P < 0.05).Conclusion: In patients receiving steroids, and particularly dexamethasone, an earlier reversal of neuromuscular block by sugammadex was found, in contrast with what one expect. Further studies are required to determine the cause of this effect which is probably due to a potential interaction between sugammadex and steroids.Keywords: Anesthesia, steroids, sugammadex, train‑of‑four monitorin