Bibliographic record
Abstract
Thermal analyses (DTA and TG) were carried out on sturmanite and ettringite from the Kalahari Manganese Field, South Africa. The TG trace for sturmanite, approximately Ca6(Fe3+1.5Al0.3Mn2+0.2)2.0{[B(OH)4]1.2(SO4)2.3}3.5(OH)12•25H2O, indicates that H2O(g) is lost at about 135°C, SO3(g) is lost at about 1349°C, and the residue melts at about 1154°C. In sturmanite, a polymorphic transition occurs at about 627°C. For ettringite, approximately Ca6Al2(SO4)3(OH)12•26H2O, the H2O(g) and SO3(g) are lost at about 149 and 753°C, respectively, and the residue melts at about 1176°C. Ettringite melts after the liberation of both H2O(g) and SO3(g), whereas sturmanite melts after the liberation of H2O(g). The loss of SO3(g) occurs at a considerably lower temperature in ettringite than in sturmanite. Using powder X-ray diffraction, the unit-cell parameters for sturmanite are a 11.157(1), c 21.846(3) Å, V 2355.2(8) Å3 for the hexagonal supercell, and a 11.147(3), c 10.918(5) Å, V 1174.9(9) Å3 for the subcell. The unit-cell parameters for ettringite are a 11.223(1), c 21.474(2) Å, V 2342.2(5) Å3 for the hexagonal supercell, and a 11.229(1), c 10.732(2) Å, V 1171.9(3) Å3 for the subcell. The volume of sturmanite is only slightly larger than that of ettringite.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.003 | 0.004 |
| Science and technology studies | 0.003 | 0.002 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.347 | 0.158 |
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".