Geometric pore surface area and fractal dimension of catalyzed electrodes in polymer electrolyte membrane fuel cells
Bibliographic record
Abstract
Geometric pore surface area is a significant parameter for the description of the irregular, somewhat random, porous structure of the catalyzed electrodes in polymer electrolyte membrane (PEM) fuel cells; however, its value is sensitive to the experimental methods employed, which necessitates the measurements via different methods. In this study, the geometric surface area of the porous electrode is determined by two different methods: the method of standard porosimetry (MSP) and Brunauer-Emmett-Teller (BET). The theory of fractal dimension is employed to analyze the data obtained from the MSP, and the fractal surface area calculated using nitrogen molecules as the scale is compared with the BET surface area. The results indicate that the geometric pore surface area is a property of the porous electrode that depends greatly on the “scale” size (ie, molecule size of the working fluid)—a smaller scale yields a larger value of the surface area. The surface area determined by the BET is found to be about one order of magnitude larger than that obtained by the MSP. Thus, the fractal dimension theory based on MSP demonstrates a useful tool to determine the accessible pore surface area at different length scales.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| 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 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".