Acceleration of butane vapor nucleation by carbon dioxide gas
Bibliographic record
Abstract
Carbon dioxide (CO2) gas is known to strongly accelerate nucleation of other gas phase components, such as water and toluene. The acceleration was attributed to the formation of transient heteromolecular dimers and referred to as the chaperon mechanism. In this work, we investigate this phenomenon for butane-CO2 gas mixtures with mass spectrometry in the post-nozzle flow of a Laval expansion at a temperature of 51 K and a pressure of 40 Pa. At moderate CO2 and butane concentrations, we observed an acceleration of butane nucleation by the chaperon mechanism, albeit only by a factor of about two compared to unary butane nucleation. The fact that the chaperon mechanism is less important for butane than for water and toluene can be rationalized by the weaker intermolecular interactions between butane and CO2. At higher CO2 and butane concentrations, nucleation and cluster growth overlap in time, which leads to saturation of the measured total butane concentration. Using a kinetic model, we show that saturation is caused by the formation of heteromolecular butane-CO2 clusters of different sizes and compositions. Studies on nucleation at low temperatures in such systems are relevant for flue or natural gas separation.
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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) | 0.002 | 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".