Improvement of micro-perforated panel absorbers sound performance using resistive screens and sensitivity analysis of the composite absorber models
Why this work is in the frame
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Bibliographic record
Abstract
The sound attenuation performance of a composite absorber constituted by a micro- perforated panel, a resistive screen that is inserted into the air cavity and a rigid back plate, is studied. Using a nonlinear acoustic impedance model, the surface impedance of the absorber is determined by transfer matrix method, and the models are validated by comparison with experimental measurements performed at different sound pressure levels up to 150 dB. The contribution of the resistive screens in improving the acoustic performances of micro-perforated panel absorbers is presented. It is shown that the resistive screen increases the resistance of the absorber resulting in broadening of the absorption frequency band and improvement of the absorption coefficient when an appropriate perforation ratio of the panel is used. Sensitivity analysis is performed at higher pressure excitations, and the dimensionless input parameters are the perforation ratio of the panel, the ratio of the perforation diameter by the thickness of the panel, the ratio of the cavity depth by the thickness, the orifice Mach number and the resistance per unit area of the screen. The analysis shows the impact of the input parameters on the normalized surface impedance and the sound absorption coefficient of the absorber. It is demonstrated that the resistance per unit area of the screen influences strongly the acoustic properties of the absorber in the linear regime, while the perforation ratio of the panel and the orifice Mach number are the dominant parameters which control the acoustic behavior of the absorber in the nonlinear regime.
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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 | 0.001 | 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 | 0.000 |
| 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 it