Effects of Poly(vinylpyrrolidone) on the Dynamic Viscosity of Methane Hydrate Systems at High-Pressure Driving Forces: Investigation of Concentration, Molecular Weight, and Shear Rate
Bibliographic record
Abstract
The viscosity of methane hydrate slurries with poly(vinylpyrrolidone) (PVP) at 700 and 7000 ppm by weight, molecular weights of 40 000 (PVP40) and 360 000 (PVP360) Da, and shear rates of 400 and 80 s –1 were measured in a high-pressure rheometer with pressures up to 30 MPag and compared to pure water systems. The additives successfully reduced the formation of high-viscosity slurries but at low concentrations were incapable of delaying hydrate agglomeration at the late growth stage. The average relative time required for PVP40 solutions at 700 ppm to grow to 50 mPa·s was 1.9 times the water reference value but only 1.2 times to reach 200 mPa·s. Improved inhibition was observed for the higher concentration and higher molecular weight sets, where the relative times to reach 50 mPa·s were 8.2 and 2.6 times the water reference value, respectively. While the additives demonstrated antinucleation properties and suppressed crystal growth initially, they accelerated the hydrate clusters agglomeration rate and potentially weakened the hydrate mechanical properties.
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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 | 0.001 |
| 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 | 0.001 |
| 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".