Melting and Fluid Behavior of Asphaltene Films at 200−500 °C
Bibliographic record
Abstract
The behavior of the asphaltene fraction in crude oils and bitumens plays a significant role in production, separation, and transportation, but low-temperature precipitation measurements are of limited value in projecting the physical state at refining temperatures. The melting behavior of five types of asphaltenes was observed by heating thin films at ca. 16.5 °C/s on Curie-point alloys in an inert atmosphere. The heptane-insoluble asphaltenes from Arab Heavy, Arab Light, Athabasca, Gudao, and Maya all showed evidence for formation of a liquid melt at temperatures between 214 and 311 °C, which was significantly lower than initial reaction temperatures of ca. 400 °C. The majority of the n -heptane-insoluble asphaltenes must exist, therefore, in either a molten phase or as a solution at process temperatures typical of distillation and reaction. With an average melting temperature of 294 °C, the Maya melting point was significantly higher than the melting points of Athabasca, Arab Light, and Arab Heavy, which were in the range of 224−245 °C. This difference in melting point did not correlate with any average chemical 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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.003 | 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".