Disordering during melting: An <sup>17</sup> O NMR Study of crystalline and glassy CaTiSiO <sub>5</sub> (titanite)
Bibliographic record
Abstract
Although titanite (CaTiSiO 5 ) has one of the highest known entropies of fusion among silicates, the corresponding melt is a relatively good glass-former, which provides an opportunity to investigate the structural origin of disorder in the liquid. Here we present an 17 O NMR study of CaTiSiO 5 glass, using detailed new results on the crystalline phase, collected at magnetic fields of 9.4, 14.1, 18.8, and 21.1 Tesla, to interpret the spectra. We find that the glass contains significant concentrations of Si-O-Si and Si-O-Ca sites in addition to the Ti-O-Ti and Ti-O-Si sites of the crystal, suggesting considerable network disorder. Simulations of the spectra for the crystal allow the derivation of isotropic chemical shifts and quadrupolar coupling constants (C Q ) for each of the five O atom sites. In addition the Ti-O-Ti site has an unusually large chemical shift anisotropy and an unusually small C Q value.
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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".