Dispersion of Asphaltene Nanoaggregates and the Role of Rayleigh Scattering in the Absorption of Visible Electromagnetic Radiation by These Nanoaggregates
Bibliographic record
Abstract
Asphaltenes exist in the form of a colloidal dispersion in crude oils and solvents. Even in a good solvent such as toluene, asphaltene aggregates persist at the nanoscale. In this study, the impact of Rayleigh scattering on the apparent absorption of visible radiation by asphaltene aggregates in solution was assessed. Recent work with a stirred diaphragm diffusion cell indicates that membranes with pore sizes less than 5 nm are capable of removing the species responsible for the absorption of visible light with wavelengths >550 nm. A further analysis of the spectra of the whole asphaltene samples in toluene indicates that the absorbance of visible light with wavelengths >600 nm follows a λ –4 dependence for asphaltenes from a range of sources over a wide range of concentration. This functional dependence is consistent with Rayleigh scattering, rather than a mixture of colored components or chromophores. Rayleigh scattering equations were combined with experimental visible spectra to estimate the average nanoaggregate sizes, which were in a very good agreement with the sizes reported in the literature by other methods. Various additives, solvents, and ultrasound and heat treatments were employed in an attempt to completely disaggregate the asphaltene nanoaggregates in solution at room temperature. None of the treatments eliminated nanoaggregration, but some treatments increased absorption due to formation of larger aggregates, as confirmed by acoustic spectroscopy.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".