Fluid Properties of Asphaltenes at 310−530 °C
Bibliographic record
Abstract
The viscosity and surface tension of n -heptane-insoluble asphaltenes and asphaltene−vacuum residue blends were determined by measuring the forces on liquid bridges between thin films. Asphaltenes from a variety of heavy oils and bitumens gave surface tensions in the range of 15−19 mN/m at 358 °C and viscosities of 9−16 Pa s. At temperatures above ca. 400 °C, the viscosity increased to as much as 70 Pa s because of cracking and coke formation, whereas the surface tension declined to values as low as 5 mN/m. The properties of vacuum residues and blends of residue and asphaltenes all approached the properties of the asphaltenes at high temperature, because of extensive cracking and devolatilization. The contact angles of the asphaltene melts were in the range of 18°−57° on Ni/Fe and coke surfaces. The differences in fluid properties between asphaltenes did not correlate with the average chemical characteristics.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".