Dilational Interfacial Rheology for Increasingly Deasphalted Bitumens and <i>n</i>-C5 Asphaltenes in Toluene/NaHCO<sub>3</sub> Solution
Bibliographic record
Abstract
Understanding the properties and behaviors of diluted bitumen/water interfaces under stresses is important for remediating emulsion problems in bitumen production. We studied the dilational interfacial rheology of toluene-diluted mineral-free Athabasca bitumen, its n -pentane ( n -C5) asphaltenes, and partially deasphalted Athabasca bitumens in a NaHCO 3 solution. n -Heptane ( n -C7) added in increasing mass ratios to diluted bitumen produced the partially deasphalted bitumens. The solvent-free deasphalted bitumens and the precipitated n -C7 asphaltenes were recovered for study. The number averaged molecular weight ( M n ) of the samples was first measured as a function of the mass concentration in toluene. The slopes of these curves indicated that asphaltenes showed higher aggregation tendencies than the bitumens. This tendency was reduced significantly for the deasphalted bitumens. For all oscillation frequencies studied, the interfacial viscoelastic modulus of Athabasca bitumen-in-toluene reached a maximum at 0.865 g·L –1 (0.1 wt%) bitumen, then declined as the bitumen concentration increased. The n -C5 asphaltenes-in-toluene made up at the same concentration at which they occur in the diluted bitumen showed higher elastic and viscous moduli than those for the diluted source bitumen, at all frequencies tested. Both systems showed direct dependence of viscoelasticity on the logarithm of frequency; the n -C5 asphaltenes showed a higher viscoelasticity gradient than that for the bitumen. Distinct differences between the interfacial properties for asphaltenes-in-toluene/water vs source bitumens-in-toluene/water were observed. The interfacial viscoelasticity values for the partially deasphalted bitumens also show apparent dependence on the mass ratio of resins to residual asphaltenes (R/A). Different asphaltene aggregates present in the bitumens may also influence the R/As correlated with reduced elasticity. The interfacial behaviors of asphaltenes only in toluene are thus not indicative of those of bitumens.
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 | 0.000 | 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".