1. Kai Ming Li School of Mechanical Engineering Research in Environmental Acoustics Ray W. Herrick Laboratories

2. Current Research Areas Physical AcousticsPhysical Acoustics  Propagation of sound waves  Physical Phenomena: Diffraction, Reflection, Refraction, and Scattering Propagation of sound in a complex urban and sub-urban environmentsPropagation of sound in a complex urban and sub-urban environments Environmental NoiseEnvironmental Noise Innovation for sound absorption at low frequenciesInnovation for sound absorption at low frequencies Noise/Vibration interactionNoise/Vibration interaction Room AcousticsRoom Acoustics

3. Methodologies Analytical formulation – enhance understanding of the fundamentals Numerical simulations –Ray tracing technique, Fast Field Program, Parabolic Equation, time-domain finite difference computations Indoor scale model experiments Outdoor full scale measurements

4. Selected Recent Results No Treatment Diffuser Arrangement I Diffuser Arrangement II Comparisons of measured noise level attenuations in a “T” shape corridor with and without diffusers (QRD type). The plots show sound pressure level (SPL) reductions with referring to 1m free field levels in 1/3 octave bands of (a) 800 Hz, (b) 1000 Hz and (c) 1600 Hz.

5. Future Directions Detection of buried objects under outdoor ground surfacesDetection of buried objects under outdoor ground surfaces Optimal control of low-frequency noise by smart structuresOptimal control of low-frequency noise by smart structures Acoustical Characteristics of sound absorption materialsAcoustical Characteristics of sound absorption materials Monitoring of environmental noiseMonitoring of environmental noise Human perception of low-frequency soundHuman perception of low-frequency sound Propagation of low-frequency sound and vibration in urban and suburban environmentsPropagation of low-frequency sound and vibration in urban and suburban environments