Structural studies of gas hydrates
Bibliographic record
Abstract
An overview of recent structural work focusing on the gas hydrates of methane and carbon dioxide is given. Both the crystal structure and the microstructure are considered. We report on the pressure-dependent molecular structure of methane clathrate hydrate using laboratory-made hydrogenous and deuterated samples investigated by neutron and hard-X-ray synchrotron diffraction experiments. The isothermal compressibilities are determined for hydrogenated and deuterated CH4 hydrate, and isotopic differences between both compounds are established for the first time. The cage filling of carbon dioxide and methane hydrate is determined and compared with predictions from statistical thermodynamic theory. In the case of small cages in methane hydrate, experimental results and predictions do not agree. Field-emission scanning electron microscopy reveals the meso- to macro-porous nature of gas hydrates formed with an excess of free gas. Furthermore, in situ measurements of the formation kinetics of porous hydrates are reported in which differences between methane and carbon dioxide are established quantitatively and the transient existence of a type II carbon dioxide structure is found. PACS Nos.: 82.75-z, 61.10Nz, 61.12Ld, 68.37Hk
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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".