Download or read book Global Model for Sound Absorption in Sea Water Parts 1 3 written by R. H. Mellen and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Model for Sound Absorption in Sea Water written by R. H. Mellen and published by . This book was released on 1987 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Model for Sound Absorption in Sea Water Part 3 Arctic Regions written by and published by . This book was released on 1987 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sound absorption in sea water is known to be caused by ionic relaxations involving magnesium sulfate, boric acid and magnesium carbonate. Absorption is regionally dependent, due mainly to the pH-dependence of the boric acid relaxation. In the nominal sea-water pH range 7.7-8.3, the magnitude increases by roughly a factor of four at the lower frequencies. Since pH varies with depth as well as location, absorption also depends on the ray paths. A predictive global model for the World Ocean has developed, employing contour charts of the pH correction-factor (K-factor) at the depths, 0, 0.5, 1, 2, and 4 km. Profiles required for loss-integration along ray paths can be generate by the algorithm provided. This report extends the model to cover Arctic regions. In polar waters, sound speed generally increases monotonically with depth and upward refraction causes a concentration of energy near the surface. Excess attenuation, evidently due to underice scattering, makes long-range propagation feasible only at very low frequencies. Reverberation is also an order of magnitude higher than that at lower latitudes. Thus absorption effects are important only for direct-paths and high frequencies. For depths of 1 km or less, the ranges of concern are therefore on greater than about 50 km in ice- covered waters. The range of pH in the Arctic Ocean is roughly 8.0-8.3, corresponding to an absorption range of a factors of two at most. Because the variability occurs much closer to the surface, the depths 0, 0.1, 0.3, 0.5 and 1 km are found only in basin regions and variability is negligible at these depths.
Download or read book Global Model for Sound Absorption in Sea Water written by R. H. Mellen and published by . This book was released on 1987 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Model for Sound Absorption in Sea Water Impact Study written by and published by . This book was released on 1988 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report examines the impact of the model on sonar performance and the surface and bottom-loss models upon which predictions are currently based. The present analysis is limited mainly to active systems operating in the frequency range 3-4 kHz. The four regions examined are: North Atlantic, North Pacific, Eastern Mediterranean and Norwegian Sea. Comparison of K model predictions with those based on the Thorp formula indicates that two-way path absorption for the first CZ zone ranges from approximately 4 dB less in the North Pacific to 12 dB greater in the Eastern Mediterranean. In the bottom- bounce mode, these values are reduced roughly in proportion to range. The MGS bottom-loss model is based on analysis of one-way paths using the Thorp formula. The difference between the K model and Thorp formula for 10 degree grazing angle in the Eastern Mediterranean is roughly 4 bB, making the actual bottom-loss smaller by about on province number. the differences decrease with increasing grazing angle and are smaller in the other areas. Corrections to the MGS model should therefore be relatively minor.
Download or read book Global Model for Sound Absorption in Sea Water Part 2 GEOSECS PH Data Analysis written by and published by . This book was released on 1987 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ionic relaxations involving magnesium sulfate, boric acid and magnesium, carbonate are known to account for sound absorption in sea water. Regional dependence of sound absorption has been shown to be caused mainly by the pH-dependence of the boric acid relaxation. In the nominal sea water pH range 7.7-8.3, the magnitude can be expected to vary over neatly a factor of four at lower frequencies. Since pH varies with depth as well as locations, net absorption will also depend on the ray paths. An interim global model, based on published pH contours for the World Ocean, has been proposed. Correction factors for the sound-channel, convergence-zone and surface-duct modes are provided by individual contour charts. However, if there is no clearly dominant propagation mode, integrations of loss over all ray paths may be indicated, which requires profiles of correction-factor vs depth. Part-2 reports analysis of pH data obtained during the GEOSECS expeditions 1972-1978. The purpose is to check the accuracy of the global model contous charts and to investigate methods of estimating profiles of correction-factor vs depth. PH profiles for all the stations reported in the Atlantic, Pacific, and Indian Oceans are presented graphically and derived correction factors are listed in tables. Correction- factor contour charts at depths 0, 0.5, 1, 2, an 4 km are also developed and agreement with the earlier versions appears to be within expected experimental error. The five values provided by the contour charts should permit reasonably accurate estimation of the correction-factor profiles in most of the World Ocean.
Download or read book Scientific and Engineering Studies written by R. H. Mellen and published by . This book was released on 1987 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1987-08 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Treatise on Geochemistry written by and published by Newnes. This book was released on 2013-10-19 with total page 14787 pages. Available in PDF, EPUB and Kindle. Book excerpt: This extensively updated new edition of the widely acclaimed Treatise on Geochemistry has increased its coverage beyond the wide range of geochemical subject areas in the first edition, with five new volumes which include: the history of the atmosphere, geochemistry of mineral deposits, archaeology and anthropology, organic geochemistry and analytical geochemistry. In addition, the original Volume 1 on "Meteorites, Comets, and Planets" was expanded into two separate volumes dealing with meteorites and planets, respectively. These additions increased the number of volumes in the Treatise from 9 to 15 with the index/appendices volume remaining as the last volume (Volume 16). Each of the original volumes was scrutinized by the appropriate volume editors, with respect to necessary revisions as well as additions and deletions. As a result, 27% were republished without major changes, 66% were revised and 126 new chapters were added. In a many-faceted field such as Geochemistry, explaining and understanding how one sub-field relates to another is key. Instructors will find the complete overviews with extensive cross-referencing useful additions to their course packs and students will benefit from the contextual organization of the subject matter Six new volumes added and 66% updated from 1st edition. The Editors of this work have taken every measure to include the many suggestions received from readers and ensure comprehensiveness of coverage and added value in this 2nd edition The esteemed Board of Volume Editors and Editors-in-Chief worked cohesively to ensure a uniform and consistent approach to the content, which is an amazing accomplishment for a 15-volume work (16 volumes including index volume)!
Download or read book Underwater Acoustic Modeling and Simulation written by Paul C. Etter and published by CRC Press. This book was released on 2018-04-06 with total page 639 pages. Available in PDF, EPUB and Kindle. Book excerpt: This newest edition adds new material to all chapters, especially in mathematical propagation models and special applications and inverse techniques. It has updated environmental-acoustic data in companion tables and core summary tables with the latest underwater acoustic propagation, noise, reverberation, and sonar performance models. Additionally
Download or read book Ambient Noise in the Sea written by Robert J. Urick and published by . This book was released on 1984 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Underwater Acoustic Modeling and Simulation Fourth Edition written by Paul C. Etter and published by CRC Press. This book was released on 2013-02-21 with total page 557 pages. Available in PDF, EPUB and Kindle. Book excerpt: Underwater Acoustic Modeling and Simulation, Fourth Edition continues to provide the most authoritative overview of currently available propagation, noise, reverberation, and sonar-performance models. This fourth edition of a bestseller discusses the fundamental processes involved in simulating the performance of underwater acoustic systems and emphasizes the importance of applying the proper modeling resources to simulate the behavior of sound in virtual ocean environments. New to the Fourth Edition Extensive new material that addresses recent advances in inverse techniques and marine-mammal protection Problem sets in each chapter Updated and expanded inventories of available models Designed for readers with an understanding of underwater acoustics but who are unfamiliar with the various aspects of modeling, the book includes sufficient mathematical derivations to demonstrate model formulations and provides guidelines for selecting and using the models. Examples of each type of model illustrate model formulations, model assumptions, and algorithm efficiency. Simulation case studies are also included to demonstrate practical applications. Providing a thorough source of information on modeling resources, this book examines the translation of our physical understanding of sound in the sea into mathematical models that simulate acoustic propagation, noise, and reverberation in the ocean. The text shows how these models are used to predict and diagnose the performance of complex sonar systems operating in the undersea environment.
Download or read book Proceedings of the International Congress on Acoustics written by and published by . This book was released on 1992 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1989 with total page 1004 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index Corporate author written by and published by . This book was released on 1987 with total page 1028 pages. Available in PDF, EPUB and Kindle. Book excerpt:
