Air-coupled ultrasound using broadband shock waves from piezoelectric spark igniters
Bibliographic record
Abstract
We used an optomechanical sensor to study the ultrasound generated by manually operated piezoelectric spark igniters. These low-energy sparks produce short-duration acoustic shock-wave pulses, with sub-microsecond rise times and frequency content extending well beyond 2 MHz in air. The same source-receiver combination was then used to demonstrate broadband characterization of solid (polymer and glass) plates in a simple setup, where single spark events yielded high-SNR data without the need for critical alignment. This setup also enabled us to estimate pressure excursions approaching 105 Pa at millimeter-scale distances from the spark. The results are in large part made possible by the small size, wide bandwidth, and high sensitivity of the optomechanical sensor, and might be of interest for air-coupled ultrasound applications in non-destructive testing.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".