Study of EIS Behavior of Air-Starved Cells Over Different Cell-Counts in a PEM Air-Cooled Stack
Bibliographic record
Abstract
This paper presents results from a set of experiments performed on a Ballard air-cooled PEM stack equipped with an Electrochemical Impedance Spectroscopy (EIS) system that permits measuring impedance over different cell-counts. The EIS scans were collected over a single cell as well as a collection of 2/5/10/20/35 & 50 cells spanning the original single cell. The intent of this research testing was to first understand how the EIS of single-and multiple-air-starved cells ‘add’ in a stack of mostly ‘good’ cells, and then to learn the required conditions for detecting significant internal transfers or hydrogen crossover within an air-cooled stack. Nitrogen was injected into the air stream entering the target cell at various rates to dilute the oxygen on the cathode side to emulate the phenomena of crossover recombination. It was found that EIS signatures of healthy cells within a stack are fully additive. Furthermore, adding a single cell with a relatively low oxygen concentration resulting from higher nitrogen injection rates generated large low-frequency arcs that showed even in scans of one air-starved cell in a large pool of healthy cells.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".