Propagation Loss Modelling on the Scotian Shelf

Propagation Loss Modelling on the Scotian Shelf PDF Author: David M. F. Chapman
Publisher: Dartmouth, N.S. : Defence Research Establishment Atlantic
ISBN:
Category : Underwater acoustics
Languages : en
Pages : 54

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Propagation Loss Modelling on the Scotian Shelf

Propagation Loss Modelling on the Scotian Shelf PDF Author: David M. F. Chapman
Publisher: Dartmouth, N.S. : Defence Research Establishment Atlantic
ISBN:
Category : Underwater acoustics
Languages : en
Pages : 54

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Technical Abstract Bulletin

Technical Abstract Bulletin PDF Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 104

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Bottom-Interacting Ocean Acoustics

Bottom-Interacting Ocean Acoustics PDF Author: William A. Kuperman
Publisher: Springer Science & Business Media
ISBN: 1468490516
Category : Science
Languages : en
Pages : 700

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Book Description
vi These categories seem to represent the basic breakdown by field of present-day research in this area. Though each paper has been classified into one of these categories (for conference organization purpose), many papers overlapped two or three areas. It is also interesting to note that not only are scientific results being communicated, but the latest techniques and the state-of-the-art tools of the trade (existing and in development) are also being presented. The forty-six papers presented at this conference represent the work of seventy scientists working at universities, government laboratories, and industrial laboratories in seven different countries . We would like to thank the contributors for their efforts and especially for their promptness in providing the editors with their final manuscripts. William A. Kuperman Finn B. Jensen La Spezia, Italy July 1980 CONTENTS GEOACOUSTIC PROPERTIES OF MARINE SEDIMENTS Attenuation of Sound in Marine Sediments . • 1 J. M. Hovem Directivity and Radiation Impedance of a Transducer 15 Embedded in a Lossy Medium . •• •••••• G. H. Ziehm Elastic Properties Related to Depth of Burial, Strontium Content and Age, and Diagenetic Stage in Pelagic Carbonate Sediments . . • • . • • • . 41 M. H. Manghnani, S. O. Schianger, and P. D. Milholland Application of Geophysical Methods 'and Equipment to Explore the Sea Bottom . •• •••. • 53 H. F. Weichart The Acoustic Response of Some Gas-Charged Sediments in the Northern Adriatic Sea • • • • . • • • • 73 A.

Impact of Littoral Environmental Variability on Acoustic Predictions and Sonar Performance

Impact of Littoral Environmental Variability on Acoustic Predictions and Sonar Performance PDF Author: Nicholas G. Pace
Publisher: Springer Science & Business Media
ISBN: 9401006261
Category : Science
Languages : en
Pages : 592

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Book Description
The limiting influence of the environment on sonar has long been recognised as a major challenge to science and technology. As the area of interest shifts towards the lit toral, environmental influences become dominant both in time and space. The manyfold challenges encompass prediction, measurement, assessment and adaptive responses to maximize the effectiveness of systems. Although MCM and ASW activities are dom inated in different ways and scales by the environment, both warfare areas have had to consider the significantly changing requirements posed by operations in the littoraL The fundamental scientific issues involved in developing models relating acoustics to the environment are matched in difficulty by the need for data for their validation and eventual practical use for prediction. In many instances the need is for on-line adaptation of systems to changing circumstances whilst other needs are for the Ionger term planning activities. This book and the attached full-color CD are the proceedings of a conference organ ised by the SACLANT Undersea Research Centre, held at Villa Marigola, Lerici, Italy, on 16-20 September 2002. The fundamental problems associated with environmental 1 variability and sonar were explored at a previous SACLANTCEN conference in 1990. These problems have not gone away but, on the one hand are exaggerated by the move to the littoral and on the other hand, are open to treatrnent in new ways that advances in technology and computer power allow.

Offshore Site Investigation

Offshore Site Investigation PDF Author: Society for Underwater Technology (SUT)
Publisher: Springer Science & Business Media
ISBN: 9401173583
Category : Science
Languages : en
Pages : 308

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c. P. Wroth, Oxford University, UK I am grateful to the Organising Committee that were covered on the first day. First, we for the invitation to attempt to sum up the had Dr Riemersma talking about positioning proceedings. Summing up is not really the requirements, and it seemed to me to be an appropriate phrase - it is a difficult job to unhappy reflection on human frailty that he do justice in a summary to the amount of was concentrating so much on the errors in material that has been presented over the the system and on the human factors that two days of the conference. Clearly, each led to trouble, emphasizing that the techni paper merits further individual attention in ques are vastly superior to the ability of the order to reflect on its content. What I am human beings who used them. Then, Dr going to say must necessarily be an unbal Palmer talked about a fascinating case his anced critique, because we are considering a tory of the Ocean Thermal Power Project; whole range of knowledge and experience in this was of particular interest because most a wide diversity of topics, and my comments of the other stories we heard were not so are bound to be biased by my own interests. specific and not about such a novel project.

Shear Waves in Marine Sediments

Shear Waves in Marine Sediments PDF Author: J.M Hovem
Publisher: Springer Science & Business Media
ISBN: 9401135681
Category : Science
Languages : en
Pages : 593

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Book Description
Shear waves and closely related interface waves (Rayleigh, Stoneley and Scholte) play an important role in many areas of engineering, geophysics and underwater acoustics. In some cases interest is focused on large-amplitude waves of low frequency such as those associ ated with earthquakes and nuclear explosions; in other cases low amplitude waves, which have often travelled great distances through the sediment, are of interest. Both low and high frequency shear and interface waves are often used for seafloor probing and sediment characterization. As a result of the wide spectrum of different interests, different disciplines have developed lines of research and a literature particularly suited to their own problems. For example water-column acousticians view the seafloor sediment as the lower boundary of their domain and are interested in shear and interface waves in the near bottom sediments mainly from the standpoint of how they influence absorption and reflection at this boundary. On the other hand, geophysicists seeking deep oil deposits are interested in the maximum penetration into the sediments and the tell-tale characteristics of the seismic waves that have encountered potential oil or gas bearing strata. In another area, geotechnical engineers use shear and interface waves to study soil properties necessary for the design and the siting of seafloor structures.

Ocean Seismo-Acoustics

Ocean Seismo-Acoustics PDF Author: T. Akal
Publisher: Springer Science & Business Media
ISBN: 1461322014
Category : Science
Languages : en
Pages : 898

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Book Description
Seafloor investigation has long been a feature of not only seismology but also of acoustics. Indeed it was acoustics that produced depth sounders, giving us the first capability of producing both global and local maps of the seafloor. Subsequently, better instrumentation and techniques led to a clearer, more quantitative picture of the seabed itself, which stimulated new hypotheses such as seafloor spreading through the availability of more reliable data on sediment thickness over ocean basins and other bottom features. Geologists and geophysicists have used both acoustic and seismic methods to study the seabed by considering the propagation of signals arising from both natural seismic events and man-made impulsive sources. Although significant advances have been made in instrumentation, such as long towed geophysical arrays, ai r guns and ocean bot tom seismometers, the pic ture of the seafloor is still far from complete. Underwater acoustics concerns itself today with the phenomena of propagation and noise at frequencies and ranges that require an understanding of acoustic interaction at both of its boundaries, the sea surface and seafloor, over depths ranging from tens to thousands of meters. Much of the earlier higher frequency (>1 kHz) work included the characterization of the seafloor in regimes of reflection coefficients which were empirically derived from surveys. The results of these studies met with only limited success, confined as they were to those areas where survey data existed and lacking a physical understanding of the processes of reflection and scattering.

Marine Acoustics

Marine Acoustics PDF Author: James L. Buchanan
Publisher: SIAM
ISBN: 0898715474
Category : Science
Languages : en
Pages : 344

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Book Description
Marine Acoustics: Direct and Inverse Problems presents current research trends in the field of underwater acoustic wave direct and inverse problems. It is the first to investigate inverse problems in an ocean environment, with heavy emphasis on the description and resolution of the forward scattering problem.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 704

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Marine Mammals and Noise

Marine Mammals and Noise PDF Author: W. John Richardson
Publisher: Academic Press
ISBN: 0080573037
Category : Science
Languages : en
Pages : 593

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Book Description
Many marine mammals communicate by emitting sounds that pass through water. Such sounds can be received across great distances and can influence the behavior of these undersea creatures. In the past few decades, the oceans have become increasingly noisy, as underwater sounds from propellers, sonars, and other human activities make it difficult for marine mammals to communicate. This book discusses, among many other topics, just how well marine mammals hear, how noisy the oceans have become, and what effects these new sounds have on marine mammals. The baseline of ambient noise, the sounds produced by machines and mammals, the sensitivity of marine mammal hearing, and the reactions of marine mammals are also examined. An essential addition to any marine biologist's library, Marine Mammals and Noise will be especially appealing to marine mammalogists, researchers, policy makers and regulators, and marine biologists and oceanographers using sound in their research.