Scale-model investigation of the effects of surface absorption and nearby foliage on noise-barier performance
Bibliographic record
Abstract
Two factors that may affect the acoustical performance of highway noise barriers -surface absorption and nearby vegetation -were investigated using a 1:31.5-scalemodel highway.Model materials were chosen by performing excess-attenuation measurements and a best fit to find the effective flow resistivity.Surface absorption was tested on single and parallel noise barriers of varying heights, allowing for a comparison between adding absorption and increasing the height.Foliage tests were performed on single and parallel barriers with various configurations of model trees.Barrier absorption prevented the amplification of sound between parallel barriers; in this case, adding absorption to the full source side of the barriers was equivalent to increasing the height of the barriers by 0.33 m.The foliage test results showed that both scattering and absorption occurred, increasing and decreasing barrier performance by up to 4 dB. s o m m a i r eDeux facteurs qui peuvent influencer la performance acoustique des écrans routiers -l'absorption des surfaces et de la végétation adjacente -ont été étudiés à l'aide de la maquette d 'une configuration routière à l 'échelle réduite de 1:31.5.Les matériaux pour la maquette ont été choisis par l 'intermédiare de tests d 'atténuation excédentaire qui permettaient de determiner la meilleure approximation de la résistivité à l 'écoulement à partir des mesures prises.L 'effet de l 'absorption surfacique a été testé sur des écrans simples et paralèlles de différentes hauteurs, ce qui a permis une comparaison entre les effets de l 'absorption et d 'un écran plus haut.D 'autres tests ont été faits avec des écrans simples et paralèlles en présence de diverses configurations de végétation.L 'absorption surfaçique a empêché l'amplification du son entre les écrans paralèlles; le rajout de l 'absorption à la surface entière de l'écran côté source a été équivalent à une augmentation de la hauteur de l 'écran de 0,33 m.Quant à la végétation, elle a causé et de la diffusion et de l'absorption, tout en augmentant et diminuant la performance jusqu'à 4 dB.Vol. 40 No. 4 (2012) -
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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) | 0.000 | 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) | 0.001 | 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 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".