Low-frequency noise is difficult to deal with by traditional porous material due to its inherent high acoustic impedance. This study seeks to extend the effective range of sound absorption to lower frequencies by filling a low density gas, such as helium, in the porous material. Compared with conventional air-filled absorption material, the helium-filled porous material has a much reduced chara...

The main goal of this paper is to use the multilayer perceptron neural network to suggest a 3D cube of the Total Organic Caron (TOC) in the lower Barnett shale gas reservoir. 3D Poststack seismic data recorded near two horizontal wells drilled in the lower Barnett formation are used as an input to train the neural machine, while the calculated acoustic impedance from sonic and density well-logs...

The acoustic attenuation of a single-pass, perforated concentric silencer filled with continuous strand fibers is investigated first theoretically and experimentally. The study is then extended to a specific type of hybrid silencer that consists of two single-pass perforated filling chambers combined with a Helmholtz resonator. One-dimensional analytical and three-dimensional boundary element m...

The design of the mathematical model of the respiratory system is described in the study. The model has been designed using an electro-acoustic analogy and geometrical dimensions of the morphological models of the respiratory system. The dependence of the geometrical dimension of the airways upon the total lung impedance is studied. Geometrical dimensions of adult respiratory system and neonate...

Ultrasonic impedance has directly been measured for various binary mixtures using a novel experimental technique. The mixtures are dimethyl sulphoxide with benzene, carbon tetrachloride and methanol at 295 K in different mole fraction ratios. The acoustic impedance of binary mixtures thus obtained was found to be in good agreement with those calculated from experimentally measured ultrasonic ve...