Impedance and Brewster angle measurement for thick porous layers
Bibliographic record
Abstract
For thin nonlocally reacting porous layers, a method derived from the work of [Chien and Soroka, J. Sound Vib. 43, 9–20 (1975)] has been used to localize the pole of the reflection coefficient located at a complex angle close to π∕2 and to measure the surface impedance at this angle. Measurements are performed with a small source/receiver separation. The method is used in the present work to measure the surface impedance of acoustically thick porous layers of high flow resistivity. Simulations show that the measured impedance, which is related to a complex angle close to π∕2 like for thin porous layers, is close to the impedance at grazing incidence. It is also shown that for semi-infinite layers the method provides a measure of the Brewster angle of the medium. Measurements of the cosine of the complex angle and of the related impedance on two granular media of high flow resistivity, Ottawa sand and glass beads, are in a reasonable agreement with predictions for frequencies above 1kHz for a source/receiver separation of 30cm.
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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 | 0.000 |
| 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".