Simultaneous Nitric Oxide/Atomic Oxygen Laser-Induced Fluorescence in an Arcjet Facility
Bibliographic record
Abstract
Simultaneous nitric-oxide and atomic-oxygen laser-induced-fluorescence experiments were performed in the Hypersonic Materials Environmental Test System facility at the NASA Langley Research Center. The data serve as an experimental database for validation for chemical and thermal nonequilibrium models used in hypersonic flows. Measurements were taken over a wide range of stagnation enthalpies using an Earth atmosphere simulant with a composition of 75% nitrogen, 20% oxygen, and 5% argon (by volume). These are the first simultaneous measurements of nitric-oxide and atomic-oxygen laser-induced fluorescence to be reported in literature for the Hypersonic Materials Environmental Test System facility. The maximum atomic-oxygen laser-induced-fluorescence mean signal intensity was observed at a stagnation enthalpy of approximately , whereas the maximum nitric-oxide laser-induced-fluorescence mean signal intensity was observed at a stagnation enthalpy of . The experimental results were compared to a fluorescence model that assumes equilibrium conditions in the plenum and frozen chemistry in an isentropic nozzle expansion (Mach 5). The equilibrium calculations were performed using CANTERA v2.1.1 with 16 species. The fluorescence model captured the correlation in mean atomic-oxygen laser-induced-fluorescence and nitric-oxide laser-induced-fluorescence signal intensities over a large range of stagnation enthalpies tested. The agreement between equilibrium calculations and the experimental laser-induced fluorescence signals was better for nitric oxide than atomic oxygen. Very weak correlations between single-shot atomic-oxygen laser-induced-fluorescence and nitric-oxide laser-induced-fluorescence intensities were observed in the experiments at all of the stagnation enthalpy conditions. It was found that the overall magnitude of nitric-oxide laser-induced-fluorescence fluctuations was much larger than atomic-oxygen laser-induced-fluorescence fluctuations.
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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".