A multinuclear MAS NMR study of calcium-containing aluminosilicate inorganic polymers
Bibliographic record
Abstract
Natural abundance 43Ca, 27Al and 29Si MAS NMR spectra were acquired for a series of aluminosilicate inorganic polymers (geopolymers) containing up to 50 wt% of Ca(OH)2, CaCO3, Ca3(PO4)2 and both amorphous and crystalline CaSiO3. The 27Al and 29Si MAS NMR spectra of these geopolymers were generally consistent with those of conventional materials, with their XRD diffractograms showing the presence of the added crystalline phases. Comparison of the 43Ca MAS NMR spectra with those of the calcium starting materials suggests that both the calcium silicates and Ca(OH)2 enter into the geopolymer network, but the spectra of geopolymers containing CaCO3 and Ca3(PO4)2 are identical to those of the original compound, suggesting that the role of these materials is simply as a filler. At the highest concentration of CaCO3, the 43Ca resonance of the aragonite polymorph appears in the geopolymer but disappears on heating at 400 °C for 36 h, suggesting that this is a metastable phase formed in situ under the highly alkaline conditions of geopolymer formation and in the presence of calcite nuclei.
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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".