Optimization of parallel coiled cavities of different depths in microperforated panel sound absorbers.

This paper presents a microperforated panel (MPP) sound absorber with parallel coiled-up-cavities of different-depths (PCD) and the corresponding optimization on their cavities. In this study, an analytical model is initially proposed for estimating the cavity depths of the PCD-MPP absorber upon normal incidence absorption coefficient evaluation at given resonance frequencies. Cavity effective depths and normal incidence absorption coefficient are evaluated after coiling up cavities for a compact structure.

The effects of speech intelligibility on English scientific literature reading in Chinese open-plan offices.

A laboratory experiment was conducted to study the effects of speech intelligibility on English scientific literature reading performance in Chinese open-plan offices (both the occupants' native language and ambient speech noise were Chinese). The objective performance and subject perceptions of 20 participants were tested under different speech intelligibility conditions. The results highlight the significant negative impact of speech noise on occupants' performance.