Utility of ammonium salts for the calibration of NH<sub>3</sub> sensors
Bibliographic record
Abstract
Abstract The calibration of NH3-sensing instruments has been an ongoing challenge to atmospheric chemists. Here, the potential utility of ammonium nitrate (NH4NO3), -sulfate ((NH4)2SO4), -bisulfate (NH4HSO4), -carbonate ((NH4)2CO3), and -bicarbonate (NH4HCO3) to generate gas streams containing NH3 or aerosol NH4 + calibrated by measuring the co-emitted acids was investigated. Head space vapors and aerosols were analyzed using a commercial total nitrogen (Nt) instrument modified to quantify Nt mixing ratios in both the gas- and particle phases, scanning mobility particle sizing, thermal-dissociation cavity ring-down spectroscopy, and Fourier transform infrared spectroscopy. The best results were obtained with NH4HCO3. Using a simple gas delivery setup consisting of two dilution stages and a line heater, the NH3 output from NH4HCO3 was calibrated by quantifying the stoichiometric co-emission of CO2 with a relatively inexpensive non-dispersive infrared spectrometer. The new approach constitutes a viable alternative to conventional NH3 cylinder calibration setups.
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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 | 0.001 | 0.002 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".