the paper presents the results of an investigation on the acoustic performance of vertical profile parallel barriers with quadratic residue diffuser tops and faces. a 2d boundary element method (bem) is used to predict the barrier insertion loss. the results of rigid and with absorptive coverage are also calculated for comparisons. using qrd on the top surface and faces of all vertical profile ...

Airborne sound insulation index of the noise barrier panel and the sound absorption coefficient of the barrier surface are the acoustic parameters that are usually determined in specialized laboratories, however they can be also determined in situ. Acoustic characteristics of a barrier include also the diffraction index difference determined from comparison of barriers with plain top edges and ...

construction plans are regarded as the basis of the economy in the society. any delays in the utilization of projects can cause to waste the investments and the loss of technical and economic justifications. in this paper, the barriers of on-time delivery in water projects will be scrutinized in mazandaran regional water company. so, the independent variables such as management obstacles, cultu...

We have developed a cantilever holder for spurious-free cantilever excitation in liquid by piezoactuator. In the holder, generation and propagation of an acoustic wave are suppressed by "acoustic barriers," i.e., boundaries between two materials having significantly different acoustic impedance while cantilever vibration is excited by "flexure drive mechanism" utilizing elastic deformation of a...

Understanding acoustic events and monitoring their occurrence is a useful aspect of many research projects. In particular, acoustic goniometry allows researchers to determine the source of an event based solely on the sound it produces. The vast majority of acoustic goniometry research projects used custom hardware targeted to the specific application under test. Unfortunately, due to the wide ...