| Characterization of a Mud Deposit Offshore of the Patos Lagoon, Southern Brazil |
Feb-2009 |
13 pages |
| Authors:
K T Holland; Allen H Reed; Richard W Faas; Mead A Allison; Lauro J Calliari; S E O'Reilly; W C Vaughan; A Alves; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOACOUSTICS DIV
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 | Rapid deposition of mud on the beach along the shoreface of Rio Grande do Sul, Brazil dramatically influences the normal operations in the littoral zone. In the surf zone, fluid and suspended mud opposes water-wave movement and dissipates water-wave energy; on the beach, mud limits trafficability. As part of a multinational, multidisciplinary program to evaluate the influence of mud strength, density and viscosity on water-wave attenuation, sediments were evaluated in ... |
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| Thermal Diffusivity and Strength of Tidal Flat Sediments During a Tidal Simulation |
Jan 2009 |
6 pages |
| Authors:
Allen H Reed; Jennifer L Miselis; K T Holland; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| Coastal margins and tidal flat sediment systems are some of the most complex, heterogeneous and energetically dynamic regions on earth. Tidal flats are repositories of terrigenous and biogenous sediments that are shaped by tides, waves and storms and utilized by birds and benthic organisms. They often lie adjacent to rivers that enable inland passage for ships and access to spawning grounds for fish. As such, they are subject to numerous ... |
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| Application of a New Grain-Based Reconstruction Algorithm to Microtomography Images for Quantitative Characterization and Flow Modeling |
Jun-2008 |
14 pages |
| Authors:
Stephanie Nyman; Karsten E Thompson; Allen H Reed; Clinton S Willson; Christopher D White; Janok P Bhattacharya; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOACOUSTICS DIV
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| X-ray computed microtomography (XMT) is used for high-resolution, nondestructive imaging and has been applied successfully to geologic media. Despite the potential of XMT to aid in formation evaluation, currently it is used mostly as a research tool. One factor preventing more widespread application of XMT technology is limited accessibility to microtomography beamlines. Another factor is that computational tools for quantitative image analysis have not kept pace with the imaging technology ... |
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| The Low-Frequency Sound Speed of Fluid-Like Gas-Bearing Sediments |
22-Jan-2008 |
7 pages |
| Authors:
Preston S Wilson; Allen H Reed; Warren T Wood; Ronald A Roy; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOACOUSTICS DIV
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| The low-frequency sound speed in a fluid-like kaolinite sediment containing air bubbles was measured using an acoustic resonator technique and found to be 114 m/s with negligible dispersion between 100 and 400 Hz. The sediment's void fraction and bubble size distribution was determined from volumetric images obtained from x-ray computed tomography scans. A simplified version of Wood's effective medium model, which is dependent only upon the ambient pressure, the void ... |
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| Geotechnical Properties of Fluid Mud |
Jan 2008 |
3 pages |
| Authors:
Allen H Reed; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| The goals of this project were as follows: determine the physical response of fluid and consolidated mud on water waves and quantify the changes in the consolidated mud bed that occur during the buildup towards and onset of sediment fluidization; and determine the relationship between in situ yield strength properties or the critical stress required for fluid mud to initiate flow, shear strength, and the rheologically determined properties of the ... |
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| Evidence of Dispersion in an Artificial Water-Saturated Sand Sediment |
Feb-2007 |
10 pages |
| Authors:
Preston S Wilson; Allen H Reed; Ronald A Roy; Jed C Wilbur; TEXAS UNIV AT AUSTIN DEPT OF MECHANICAL ENGINEERING
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| A laboratory experiment was conducted to measure the speed of sound in an artificial water-saturated granular sediment composed of cleaned and sorted medium-grained sand and degassed distilled water. The experiment was conducted within a range of frequencies where dispersion is predicted by a number of existing models. Between 2 and 4 kHz, the sound speed was inferred from measurements of the resonance frequencies of a thin-walled cylindrical container filled with ... |
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| Relationship Between Packing Structure and Porosity in Fixed Beds of Equilateral Cylindrical Particles |
23-Sep-2006 |
16 pages |
| Authors:
Wenli Zhang; Karsten E Thompson; Allen H Reed; Liese Beenken; LOUISIANA STATE UNIV BATON ROUGE DEPT OF CHEMICAL ENGINEERING
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| Fixed beds of cylindrical particles are important in chemical engineering applications, but their packing structures are not as well understood or as well characterized as sphere packings. In this work, X-ray microtomography is used to obtain 3D images of 1.8 mm diameter equilateral cylinders in a 23 mm cylindrical container over a range of bulk porosities. A novel algorithm is used to computationally reconstruct the packings, resulting in data sets ... |
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| Flow Through a Laboratory Sediment Sample by Computer Simulation Modeling |
07-Sep-2006 |
7 pages |
| Authors:
Allen H Reed; R B Pandey; Edward Braithwaite; Ray Seyfarth; J F Gettrust; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| A laboratory sediment sample is digitized by X-ray computed tomography system to obtain a host matrix of size 1003 of porosity 0.282. Flow through the porous medium is studied by an interacting lattice gas model for fluid driven by pressure bias. The bias H(0 less than or equal to H less than or equal to 1) is implemented via soft and hard pressure constraints in selecting the stochastic movement of ... |
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