Author : Donald J. Shirley
Publisher :
Page : 137 pages
File Size : 15,1 MB
Release : 1979
Category :
ISBN :
Work under Contract consisted of three parts: (1) redesign and updating of the ARL:UT profilometer system used to measure in situ sound velocities of ocean bottom sediments, (2) development of transducers to measure shear wave and acoustic impedance parameters of sediments, and (3) laboratory measurements to develop and confirm theoretical models for acoustic propagation in sediments. Data obtained for the three parts of the program are reported.
Author : Donald J. Shirley
Publisher :
Page : 52 pages
File Size : 12,14 MB
Release : 1977
Category :
ISBN :
During this reporting period, research was directed towards measuring sediment acoustic parameters in situ. Four field trips were made to use the ARL profilometer to make in situ sound speed measurements. Laboratory work continued to add the capability of measuring shear wave speed and acoustic impedance to the existing profilometer. Shear wave and compressional wave data measured in laboratory sediments are reported.
Author : Robert D. Stoll
Publisher : Springer
Page : 172 pages
File Size : 46,78 MB
Release : 1989-12-15
Category : Science
ISBN :
Sediment Acoustics describes the development of a mathematical model to be used to predict the propagation characteristics of acoustic waves in marine sediments. The model is based on the classical theory of Maurice Biot. Over the past 20 years, R.D. Stoll has published many technical papers covering various stages of development and different applications of Biot's theory. This work is summarized in one reference volume for the first time and presents enough introductory material so that researchers and students may use the model without extensive literature searches. Scientists working in the areas of acoustical oceanography, marine seismology, and ocean engineering will find this monograph useful in predicting the wave velocity and attenuation of seafloor sediments based on the geology of an area and such measurable physical properties as porosity and geostatic stress. A simple, interactive computer program is given as an aid in calculating velocity and attenuation, and a number of examples from recent field experiments are presented so that the predictions of the model may be compared with the "ground truth."
Author :
Publisher :
Page : 100 pages
File Size : 37,8 MB
Release : 2010
Category :
ISBN :
The primary purpose of this work was to conduct laboratory and field studies of the acoustics of sandy ocean bottom sediments, with sufficient control of experimental uncertainly to make meaningful comparisons to existing and developing models. The work began with a focus on low frequencies, below the Biot transition frequency, but expanded in frequency range to cover frequencies above the Biot transition frequency. Initially, the work was focused on sandy sediments, but additional multiphase ocean-bottom materials were eventually studied, too, including gas-bearing sediments and seagrass. The work was initially focused on laboratory measurements, but expanded to include work during the large-scale, ONR-sponsored at-sea experiment Shallow Water '06. Results of a large number of associated laboratory and field measurements are presented along with model comparisons, for the various ocean bottom materials mentioned above.
Author : Lloyd Hampton
Publisher : Springer Science & Business Media
Page : 568 pages
File Size : 48,98 MB
Release : 2013-03-09
Category : Science
ISBN : 1468408380
The phenomenon of sound transmissions through marine sediments is of extreme interest to both the United States civilian and Navy research communities. Both communities have conducted research within the field of this phenomenon approaching it from different perspectives. The academic research community has approached it as a technique for studying sedimentary and crustal structures of the ocean basins. The Navy research community has approached it as an additional variable in the predictability of sound trans mission through oceanic waters. In order to join these diverse talents, with the principal aim of bringing into sharp focus the state-of-the-science in the problems relating to the behavior of sound in marine sediments, the Office of Naval Research organized and sponsored an invited symposium on this subject. The papers published in this volume are the results of this symposium and mark the frontiers in the state-of-the-art. The symposia series were based on five research areas identified by ONR as being particularly suitable for critical review and for the appraisal of future research trends. These areas include: 1. Physics of Sound in Marine Sediments, 2. Physical and Engineering Properties of Deep-Sea Sediments, 3. The Role of Bottom Currents in Sea Floor Geological Processes, 4. Nephelometry and the Optical Properties of the Ocean I'laters, S. Natural Gases in Marine Sediments and Their Mode of Distribution. These five areas also form some of the research priorities of the ONR program in Marine Geology and Geophysics.
Author : C. K. Jonys
Publisher :
Page : 136 pages
File Size : 25,29 MB
Release : 1976
Category : Sediment transport
ISBN :
This report combines three studies on the acoustic method of sediment bed-load measurement in gravel-bearing rivers. The results of laboratory work, a theoretical feasibility study and a summary of the observations and analysis of a field investigation program are presented. Laboratory experiments were carried out to verify some acoustical aspects of impact noise in water for application in the development of a theoretical relationship between the noise generated by riverbed pebble collisions and bed-load transport rates. Underwater pebble noise was simulated by rolling ceramic balls on a bed of similar balls in a large laboratory flume. Sound was measured with a stationary hydrophone located in the water above the pebble bed. In field experiments, underwater sound samples were recorded in two gravelbearing rivers during periods with and without bed-load movement. Also, samples of artificially generated interparticle collision noise by different sizes of gravel pebbles were recorded. Flow velocities and bed-load transport were measured as well. The purpose of the observations was to obtain field data for the study of the feasibility of the acoustic method for bed-load measurement.
Author :
Publisher :
Page : 1048 pages
File Size : 19,22 MB
Release :
Category : Science
ISBN :
Author :
Publisher :
Page : 102 pages
File Size : 12,44 MB
Release : 1980
Category : Marine sediments
ISBN :
During the period 1 January - 31 December 1979, work under Contract N00014-76-C-0117 consisted of three parts: (1) use of the profilometer system to obtain in situ compressional wave data and to test in situ shear wave transducers, (2) development of theoretical models for acoustic propagation in sediments, and (3) laboratory measurements of compressional wave and shear wave parameters in laboratory sediments. Data obtained for the three parts of the program are reported. (Author).
Author : William A. Kuperman
Publisher : Springer Science & Business Media
Page : 700 pages
File Size : 36,98 MB
Release : 2013-03-13
Category : Science
ISBN : 1468490516
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.
Author :
Publisher :
Page : 82 pages
File Size : 35,12 MB
Release : 1982
Category :
ISBN :
The work consisted of (1) final development of the ARL:UT profilometer recorder and transducer to enable the in situ measurement of compressional wave, shear wave, acoustic impedance, and static shear strength of ocean bottom sediments during geophysical coring, and (2) laboratory acoustical measurements on artificial sediments to test predictions of the Hovem model when the pore fluid viscosity is varied. The new profilometer recorder and transducer are described in detail as well as the microcomputer band playback system. Data obtained from the laboratory measurements are displayed.
