Role of PVA Flakes in Promoting Self-Degradation of Sodium Metasilicate-Activated Cement under a Hydrothermal Environment at ≥150°C
Bibliographic record
Abstract
We investigated the effect of flakes of polyvinyl alcohol (PVA) on the self-degradation of sodium metasilicate (SMS)-activated slag/Class C fly ash cement, which is used as temporary sealer for fractures in Enhanced Geothermal System (EGS) wells under a hydrothermal environment at ³150°C and at pressure of 1000 psi. The reactions between PVA and SMS dissolved in an aqueous medium at 85°C led to the formation of a colloidal hydroxylated silicate-cross-linked PVA gel in the cement body. This gel-incorporated cement had a compressive strength >2000 psi, so ensuring that it adequately plugs the fractures. Increasing the hydrothermal temperature to ³150°C triggered the transformation of the gel into a sol. This in-situ gel®sol phase transition played a pivotal role in promoting the cement’s self-degradation because of the extensive spreading of sol in the cement body, and its leaching from the cement. In contrast, when gel was dry heated at ³150°C, the gel®xerogel phase transformation engendered the molecular fragmentation of PVA. This fragmentation yielded polysilicate cross-linked PVA derived from the combination of extended-chain scission, carboxylation and condensation, so that it no longer served as a self-degrading promoter of cement..
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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".