Qualitative analysis of high-pressure N2 plasma generated by dual-polarity nanosecond-pulsed discharges
Bibliographic record
Abstract
Over the last two decades, the world has seen a rapid transition from carbon-based fuel sources to renewable sources.This paradigm shift has led to a reevaluation of traditionally high energy synthesis processes, particularly the Haber-Bosch process.This utilized ammonia synthesis reaction pathway is heavily dependent on fossil fuels and is reliant on economies of scale to maximize energy yields and minimize operating costs.More flexible ammonia synthesis techniques have been theorized and tested at a laboratory scale over the last two decades, including a plasma-driven reaction pathway which has the lowest theoretical energy consumption.This Master's thesis focuses on optimizing reaction conditions for plasma-assisted ammonia production.Reaction conditions were investigated by generating nitrogen plasma at pressures from 1 to 5 atm and qualitatively analyzing the sample using optical emission spectroscopy.A dual-polarity nanosecond-pulsed power supply designed and built by McGill University's Plasma Processing Laboratory delivered consistent discharges across an interelectrode gap ranging from 1 to 5 mm between two stainless steel pin electrodes.The spectra obtained from the emission of the nitrogen plasma were then analyzed with specific attention to N2's second positive system (SPS).N2's SPS is an indicator of an excited state of nitrogen below its ionization energy.These energized particles are theorized to contribute to the enhancement of surface-based ammonia generation in catalytic reactors at milder conditions than the Haber-Bosch process.By cycling various voltage drops in a newly designed and built reactor, it was determined that the nanosecond-pulsed power supply was able to generate plasmas with spectra only displaying N2's SPS.By lowering the pressure and electrode gap distance, the power supply generated a higher energy plasma containing some ionized species, in addition to the non-ionized, energetic N2.In addition, varying frequency of pulses as a parameter influenced the amount of power being delivered into the plasma without changing the maximum electric field.This provides control over the prevalence of lower energetic states without introducing ionized species to the reactor.Phillip Servio, for their insight and contributions to my development as a researcher.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| 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 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".