Measuring Gas Diffusivity of Partially Water-Saturated Gas Diffusion Layers
Bibliographic record
Abstract
At high current densities, proton exchange membrane fuel cells produce more water, increasing the saturation level of the gas diffusion layer (GDL) and hence lowering reactant gas diffusivity. Few studies have measured the gas diffusivity of partially water-saturated GDLs due to the complexity of controlling saturation levels. This paper introduces a new ex situ method for measuring the diffusivity of partially saturated GDLs using a symmetrical modified Loschmidt cell. The diffusivity of four commercially available GDL types, with different PTFE contents, one of which includes a microporous layer, is assessed across various saturation levels. These findings are compared with existing data in the literature. The present results indicate that gas diffusivity decreases exponentially as GDL water saturation increases. Additionally, at relatively high saturation levels (i.e., >30%), the effect of the GDL microstructure becomes negligible, with water saturation becoming the dominant factor limiting gas diffusion.
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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 | 0.001 |
| 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".