Size matters: asphaltenes with enlarged aromatic cores promote heat transfer in organic phase-change materials
Bibliographic record
Abstract
Recent experiments and atomistic computer simulations have shown that asphaltene byproducts of oil refineries can serve as thermal conductivity enhancers for organic phase-change materials such as paraffin and therefore have the potential to improve the performance of paraffin-based heat storage devices. In this work, we explore how the size of the polycyclic aromatic cores of asphaltenes affects the properties of paraffin-asphaltene systems by means of atomistic molecular dynamics simulations. We show that increasing the size of the asphaltene core from 7-8 aromatic rings to ∼20 rings drastically changes the aggregation behavior of asphaltenes. Instead of relatively small, compact aggregates formed by small-core asphaltene molecules, enlarged cores promote the formation of extended single-column structures stabilized in paraffin by asphaltene's aliphatic periphery. Chemical modification of the asphaltenes by removing the periphery leads to the formation of bundles of columns. In contrast to small-core molecules, asphaltenes with enlarged cores do not suppress paraffin crystallization even at high filler concentrations. Remarkably, asphaltenes with enlarged aromatic cores are able to increase the thermal conductivity of liquid paraffin to a greater extent compared to their small-core counterparts. This effect becomes even more pronounced for modified asphaltenes without the aliphatic side groups. Overall, our computational findings suggest that asphaltenes with enlarged aromatic cores can significantly improve the performance of heat storage devices based on organic phase change materials.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".