Observation of two-step nucleation in methane hydrates
Bibliographic record
Abstract
In this work we show that homogeneous nucleation of methane hydrate can, under appropriate conditions, be a very rapid process, achieved within tens of nanoseconds. In agreement with recent experimental results on different systems, we find that the nucleation of a gas hydrate crystal appears as a two-step process. It starts with the formation of disordered solid-like structures, which will then spontaneously evolve to more recognizable crystalline forms. This previously elusive first-stage state is confirmed to be post-critical in the nucleation process, and is characterized as processing reasonable short-range structure but essentially no long-range order. Its energy, molecular diffusion and local structure reflect a solid-like character, although it does exhibit mobility over longer (tens of ns) timescales. We provide insights into the controversial issue of memory effects in methane hydrates. We show that areas locally richer in methane will nucleate much more readily, and no 'memory' of the crystal is required for fast re-crystallization. We anticipate that much richer polycrystallinity and novel methane hydrate phases could be possible.
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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".