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Full-Text Articles in Mechanical Engineering
Experimental Analysis Of Ultrasonic Multiple Scattering Attenuation Through The Air With Fine Dust, Ukyong Woo, Hajin Choi, Homin Song
Experimental Analysis Of Ultrasonic Multiple Scattering Attenuation Through The Air With Fine Dust, Ukyong Woo, Hajin Choi, Homin Song
Michigan Tech Publications
In this study, we experimentally evaluated the application of multiple scattering theory for measuring ultrasonic attenuation. Based on the independent approximation theory, the method adopted for calculating the attenuation of coherent waves through air with fine dust is discussed. To obtain a scattering wavefield, a unique ultrasonic scattering hardware was developed, and signal processing schemes were suggested. Four cases of standard particle doses (0, 0.004, 0.008, and 0.012 g) were investigated inside a chamber. The results obtained from the experiments demonstrate that the proposed signal processing approach successfully calculates the scattering attenuation, which correlates well with the applied doses of …
Numerical Analysis Of Ultrasonic Multiple Scattering For Fine Dust Number Density Estimation, Homin Song, Ukyong Woo, Hajin Choi
Numerical Analysis Of Ultrasonic Multiple Scattering For Fine Dust Number Density Estimation, Homin Song, Ukyong Woo, Hajin Choi
Michigan Tech Publications
In this study, a method is presented for estimating the number density of fine dust particles (the number of particles per unit area) through numerical simulations of multiply scattered ultrasonic wavefields. The theoretical background of the multiple scattering of ultrasonic waves under different regimes is introduced. A series of numerical simulations were performed to generate multiply scattered ultrasonic wavefield data. The generated datasets are subsequently processed using an ultrasound data processing approach to estimate the number density of fine dust particles in the air based on the independent scattering approximation theory. The data processing results demonstrate that the proposed approach …
Multi-Modal And Short-Range Transmission Loss In Ice-Covered, Near-Shore Arctic Waters, Miles B. Penhale
Multi-Modal And Short-Range Transmission Loss In Ice-Covered, Near-Shore Arctic Waters, Miles B. Penhale
Dissertations, Master's Theses and Master's Reports
In the past century, extensive research has been done regarding the sound propagation in arctic ice sheets. The majority of this research has focused on low frequency propagation over long distances. One of the most commonly used excitation methods for air-ice-water layers has been explosives. However, environmental regulation has become more stringent, disallowing the use of almost all explosive excitation types. Due to changing climate conditions in these environments, new experimentation is warranted to determine sound propagation characteristics in, through, and under thin ice sheets, in shallow water, over short distances. In April, 2016 several experiments were conducted approximately 2 …