Investigation of Subfractions of Athabasca Asphaltenes and Their Role in Emulsion Stability
Bibliographic record
Abstract
The ability to stabilize water-in-oil (W/O) emulsions for six studied asphaltene subfractions is dependent on their solubility rather than on their concentration, polarity, molecular weight, or other parameters. Paraffinic froth treatment technology recently introduced in the oil sand industry yields a clean bitumen product (<0.1 wt % water and <0.1 wt % solids) at a solvent-to-bitumen ratio above a critical value, which corresponds to the onset of asphaltene precipitation. Six subfractions of Athabasca bitumen asphaltenes were obtained by precipitation with a gradually increasing heptane-to-bitumen (H/B) ratio, from 1.25 to 40. The properties of the asphaltene subfractions obtained were investigated by elemental analysis, Fourier transform infrared (FTIR) and ultraviolet-visible (UV−vis) spectroscopy, and vapor pressure osmometry (VPO). There were no significant differences in the molecular masses of the six asphaltene subfractions. However, the aromaticity and the metalloporphyrin (vanadyl) content in the asphaltene subfractions systematically decreased as the H/B ratio increased. The first three subfractions had lower H/C ratios, as well as higher metalloporphyrin content, and were less soluble in heptane/toluene (H/T) mixtures. Also, their solubility was more sensitive to the aromaticity of the solvent. The last three subfractions had higher H/C ratios and lower metalloporphyrin content. Their solubility in H/T was greater and less sensitive to the aromaticity of the solvent.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 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".