Analysis of an MRI gradient coil duct with a micro‐perforated panel acoustic absorber
Bibliographic record
Abstract
Abstract An analytical model was developed for an MRI gradient coil duct with a micro‐perforated panel (MPP) acoustic absorber placed inside the duct. The absorption coefficients of a series of MPP absorbers with varying design parameters including diameter of the holes, perforation rate and thickness of the air gap were calculated. Boundary Element Method (BEM) models were then developed for the coil duct with MPP absorbers and porous materials with varying design parameters and material properties. The acoustic power, sound pressure levels and sound field inside the duct were calculated using the BEM. The results show that the principal advantage of an MPP acoustic absorber is its effectiveness in absorbing relatively low frequency noise. By using the proper combination of parameters, a MPP acoustic absorber can be designed to be a wide bandabsorber or a narrow band absorber at any specific central frequency. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 37B: 103–115, 2010
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".