Disaggregation of Asphaltene Aggregates in Solutions Depending upon Affinity Indices of the Hansen Solubility Parameter Using Ultrasmall-, Small-, and Wide-Angle X-ray Scattering
Bibliographic record
Abstract
Disaggregation of asphaltene aggregate in solution is investigated using ultrasmall-, small-, and wide-angle scattering of X-rays up to 300 °C under isobaric conditions. Wide-angle scattering profiles indicate that the longer range structure of asphaltene aggregates in toluene collapses around 150 °C. A further increase in the temperature to 300 °C, however, leads to a slight reversion to the aggregated state. This specific behavior in solution is discussed in terms of the transition of asphaltene from a solid to a melted state around 200 °C and the corresponding change in affinity indices of the Hansen solubility parameter (HSP) at elevated temperatures. Ultrasmall- and small-angle scattering profiles of samples in solution clearly show the correlation of asphaltene aggregation with the HSP indices. To understand a deeper insight into key aspects of asphaltene aggregation behavior, small-angle scattering of model compounds in toluene is measured. The scattering intensities of model compounds are classified into two groups: suggesting and confirming molecular structures contributing to enhanced aggregation and heteroaromatics containing sulfur, peri-condensed aromatic rings, and porphyrin.
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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 | 0.001 |
| 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".