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Marcia J. Isakson - One of the best experts on this subject based on the ideXlab platform.
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Underwater Acoustics education at the University of Texas at Austin
The Journal of the Acoustical Society of America, 2014Co-Authors: Marcia J. Isakson, Mark F. Hamilton, Clark S. Penrod, Frederick M. Pestorius, Preston S. WilsonAbstract:The University of Texas at Austin has supported education and research in Acoustics since the 1930s. The Cockrell School of Engineering currently offers a wide range of graduate courses and two undergraduate courses in Acoustics, not counting the many courses in hearing, speech, seismology, and other areas of Acoustics at the university. An important adjunct to the academic program in Acoustics has been the Applied Research Laboratories (ARL). Spun off in 1945 from the WW II Harvard Underwater Sound Laboratory (1941–1949) and founded as the Defense Research Laboratory, ARL is one of five University Affiliated Research Centers formally recognized by the US Navy for their prominence in Underwater Acoustics research and development. ARL is an integral part of UT Austin, and this symbiotic combination of graduate and undergraduate courses, and laboratory and field work, provides one of the leading Underwater Acoustics education programs in the nation. In this talk, the Underwater Acoustics education program will be described with special emphasis on the Underwater Acoustics course and its place in the larger Acoustics program. Statistics on education, funding, and placement of graduate students in the program will also be presented.
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Highlights of the Underwater Acoustics Technical Committee at the 167th Meeting of the Acoustical Society of America
The Journal of the Acoustical Society of America, 2014Co-Authors: Marcia J. IsaksonAbstract:The Underwater Acoustics (UW) technical committee (TC) is a dynamic group of investigators researching such varied fields as acoustic tomography, Underwater acoustic communications, and shallow water waveguide propagation. In this overview of the UW TC, a brief introduction of the goals and interests of the community will be followed with a series of highlights of what one can expect at the UW sessions.
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Computer modeling as teaching tool in Underwater Acoustics
The Journal of the Acoustical Society of America, 2013Co-Authors: Marcia J. IsaksonAbstract:One of the challenges of teaching Acoustics is to bridge the gap between theory and application. However, laboratory experiments are often too difficult or costly particularly for large-scale phenomena such as ray bending in ocean Acoustics. Computer modeling is a low cost, easily accessible way for students to visualize acoustic phenomena without the overhead of laboratory experiments. In the Underwater Acoustics course at the University of Texas at Austin, students develop an acoustic modeling suite throughout the course culminating in a code to solve the sonar equation for a target in a shallow water environment. Beginning with simple attenuation, students model rays bending due to sound speed profiles, modes, both propagating and leaky, reverberation, target scattering, array steering, and signal processing. Each component builds on previous code and, at the end of the course, the student has a coherent collection of Underwater acoustic modeling tools.
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An introduction to the Underwater Acoustics Technical Committee
The Journal of the Acoustical Society of America, 2012Co-Authors: Marcia J. IsaksonAbstract:Acoustics is considered the best means of remote sensing in oceans, lakes, and estuaries due to the high attenuation of electromagnetic radiation in water. The members of the Underwater Acoustics technical committee are concerned with the generation and propagation of sound in an Underwater environment as well as acoustic reflection and scattering from the seabed, sea surface and objects in the water column and on or beneath the seabed. In this talk, a short history of Underwater Acoustics will be followed by an overview of the current state of research in the field.
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Computer modeling in graduate level Underwater Acoustics
The Journal of the Acoustical Society of America, 2011Co-Authors: Marcia J. IsaksonAbstract:The more a student can become part of the teaching process, the more engaged he is. In a laboratory setting, this involves physically implementing the learned theories. However, for upper level graduate courses, laboratory experiments are often unrealistic. For example, in an Underwater Acoustics class, it is impossible for a student to physically realize ray bending in the ocean without a large-scale experiment. However, computer modeling can bridge the gap. In this example, students write their own simulation of Underwater propagation based on concepts learned in the lecture. Through the computer simulation, students manipulate the environment to determine the effects on acoustic propagation. As the course progresses, interface and target scattering and array and signal processing are added to the propagation code, leaving the student with a comprehensive ocean Acoustics modeling toolkit.
Karim G. Sabra - One of the best experts on this subject based on the ideXlab platform.
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paul langevin s contributions to the development of Underwater Acoustics
Journal of the Acoustical Society of America, 2015Co-Authors: Karim G. SabraAbstract:Paul Langevin made significant contributions to the understanding of piezoelectricity and the development of piezoceramics materials. For instance, Professor Langevin's invented the quartz sandwich transducer in 1917 for Underwater sound transmission. He subsequently used this to develop the first Underwater Sonar for submarine detection during World War I, and his work was extensively used the French and American Navy. After world war I, SONAR devices he helped developed were used in several French ocean-liners. We will review Paul Langevin’s most noteworthy contributions to the development of Underwater Acoustics.
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Paul Langevin’s contributions to the development of Underwater Acoustics
The Journal of the Acoustical Society of America, 2015Co-Authors: Karim G. SabraAbstract:Paul Langevin made significant contributions to the understanding of piezoelectricity and the development of piezoceramics materials. For instance, Professor Langevin's invented the quartz sandwich transducer in 1917 for Underwater sound transmission. He subsequently used this to develop the first Underwater Sonar for submarine detection during World War I, and his work was extensively used the French and American Navy. After world war I, SONAR devices he helped developed were used in several French ocean-liners. We will review Paul Langevin’s most noteworthy contributions to the development of Underwater Acoustics.
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An Underwater Acoustics program far from the ocean: The Georgia Tech case
The Journal of the Acoustical Society of America, 2014Co-Authors: Karim G. SabraAbstract:The Underwater Acoustics education program at the Georgia Institute of Technology (Georgia Tech) is run by members of the Acoustics and Dynamics research area group from the School of Mechanical Engineering. We will briefly review the scope of this program in terms of education and research activities as well as discuss current challenges related to the future of Underwater Acoustics education.
Adel A. Hashad - One of the best experts on this subject based on the ideXlab platform.
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Recent progress on the theoretical modeling of Underwater Acoustics induced by sonic booms
The Journal of the Acoustical Society of America, 2008Co-Authors: Johnson C. Wang, Charles P. Griffice, Adam M. Fincham, John R. Edwards, Adel A. HashadAbstract:This paper, review and status in nature, consists of three parts: (1) The salient nature and results of the published papers from an ocean sonic boom (OSB) project will be reviewed including theoretical and experimental studies of the wavy surface effect on the Underwater Acoustics, a three‐dimensional theory of Underwater Acoustics and the Underwater Acoustics induced by a sonic boom traveling at hyper‐velocity speeds. (2) New unpublished results will be reported including studies of sonic boom Underwater overpressures affected by ocean finite depth and ocean stratification (variable sound speed). These studies are possible due to the derivation of a semi‐similar transformation for the Underwater Acoustics governing equations and the application of high performance computers. (3) The preliminary results of the work‐in‐progress will also be discussed including three‐dimensional extensions of former professor H. K. Cheng's two‐dimensional wavy surface theory and laboratory verification.
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Acoustics2008/3566 Recent Progress on the Theoretical Modeling of Underwater Acoustics Induced By Sonic Booms
2008Co-Authors: Johnson C. Wang, Adam M. Fincham, John R. Edwards, C. P Grice, Adel A. HashadAbstract:by ocean finite depth and ocean stratification (variable sound speed). These studies are possible due to the derivation of a semi-similar transformation for the Underwater Acoustics governing equations and the application of high performance computers. (3) The preliminary results of the work-in-progress will also be discussed including three-dimensional extensions of former professor H. K. Cheng’s two-dimensional wavy surface theory and laboratory verification.
Johnson C. Wang - One of the best experts on this subject based on the ideXlab platform.
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Recent progress on the theoretical modeling of Underwater Acoustics induced by sonic booms
The Journal of the Acoustical Society of America, 2008Co-Authors: Johnson C. Wang, Charles P. Griffice, Adam M. Fincham, John R. Edwards, Adel A. HashadAbstract:This paper, review and status in nature, consists of three parts: (1) The salient nature and results of the published papers from an ocean sonic boom (OSB) project will be reviewed including theoretical and experimental studies of the wavy surface effect on the Underwater Acoustics, a three‐dimensional theory of Underwater Acoustics and the Underwater Acoustics induced by a sonic boom traveling at hyper‐velocity speeds. (2) New unpublished results will be reported including studies of sonic boom Underwater overpressures affected by ocean finite depth and ocean stratification (variable sound speed). These studies are possible due to the derivation of a semi‐similar transformation for the Underwater Acoustics governing equations and the application of high performance computers. (3) The preliminary results of the work‐in‐progress will also be discussed including three‐dimensional extensions of former professor H. K. Cheng's two‐dimensional wavy surface theory and laboratory verification.
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Acoustics2008/3566 Recent Progress on the Theoretical Modeling of Underwater Acoustics Induced By Sonic Booms
2008Co-Authors: Johnson C. Wang, Adam M. Fincham, John R. Edwards, C. P Grice, Adel A. HashadAbstract:by ocean finite depth and ocean stratification (variable sound speed). These studies are possible due to the derivation of a semi-similar transformation for the Underwater Acoustics governing equations and the application of high performance computers. (3) The preliminary results of the work-in-progress will also be discussed including three-dimensional extensions of former professor H. K. Cheng’s two-dimensional wavy surface theory and laboratory verification.
David R. Dowling - One of the best experts on this subject based on the ideXlab platform.
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phase conjugation in Underwater Acoustics
Journal of the Acoustical Society of America, 1991Co-Authors: Darrell R. Jackson, David R. DowlingAbstract:Phase‐conjugate mirrors are used in optics to compensate for aberrations caused by inhomogeneities in the propagation medium and by imperfections in optical components. In Acoustics, analogous behavior can be achieved by a time‐reversed retransmission of signals received by an array. Compensation for multipath propagation and array imperfections is automatic and does not require knowledge of the detailed properties of either the medium or the array. The behavior of acoustic phase‐conjugate arrays is illustrated in several examples, some highly idealized and some more realistic. The effects of aperture size and inhomogeneities in the propagation medium are treated for both the near‐field and far‐field regions. It is concluded that phase‐conjugate arrays offer an attractive approach to some long‐standing problems in Underwater Acoustics.
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Application of phase conjugation to Underwater Acoustics
The Journal of the Acoustical Society of America, 1990Co-Authors: Darrell R. Jackson, David R. Dowling, Edward O. BelcherAbstract:Phase conjugation shows promise as a means of compensating for multipath propagation and array deformation in Underwater Acoustics. In acoustic phase conjugation, an initial probe signal is received by a large, multielement array. If the output of each element is time‐reversed and retransmitted, the resulting field will converge on the location of the probe transmitter and will compensate for multipathing. Applications of phase conjugation to Underwater Acoustics will be illustrated. Constraints imposed by aperture size and time variation of the medium will be discussed. [Work supported by ONR.]
