Effect of boron oxide addition on the viscosity‐temperature behaviour and structure of phosphate‐based glasses
Bibliographic record
Abstract
Abstract In this study, nine phosphate‐based glass formulations from the system P2O5‐CaO‐Na2O‐MgO‐B2O3 were prepared with P2O5 content fixed as 40, 45 and 50 mol%, where Na2O was replaced by 5 and 10 mol% B2O3 and MgO and CaO were fixed to 24 and 16 mol%, respectively. The effect of B2O3 addition on the viscosity‐temperature behaviour, fragility index and structure of the glasses was investigated. The composition of the glasses was confirmed by ICP‐AES. The viscosity‐temperature behaviour of the glasses were measured using beam‐bending and parallel –plate viscometers. The viscosity of the glasses investigated was found to shift to higher temperature with increasing B2O3 content. The kinetic fragility parameter, m and F1/2, estimated from the viscosity curve were found to decease with increasing B2O3 content. The structural analysis was achieved by a combination of Fourier transform infrared spectroscopy and solid state nuclear magnetic resonance. 31P solid‐state magic‐angle‐spinning nuclear magnetic resonance (MAS‐NMR) showed that the local structure of the glasses changes with increasing B2O3 content. As B2O3 was added to the glass systems, the phosphate connectivity increases as the as the Q1 units transforms into Q2 units. The 11B NMR results confirmed the presence of tetrahedral boron (BO4) units for all the compositions investigated. Structural analysis indicates an increasing level of cross‐linking with increasing B2O3 content. Evidence of the presence of P‐O‐B bonds was also observed from the FTIR and 31P NMR analysis. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 764–777, 2017.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".