Thesis--Wisconsin. / Includes bibliographical references (leaf 44).

Thesis (M.A.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 111-118). Also available on the World Wide Web.

No description available.

Dredging is a critical part of maintaining the nation’s ports and harbors that play a major role in international trade. The design of dredge equipment requires knowledge of the forces expected on an average dredge. For a cutter suction dredge one of the largest forces is applied on the cutter head. To determine the design criteria for a given cutter suction dredge the forces on the cutter head must be known. Forces on a 33 cm (13 inch) model cutter head have been measured using a model cutter suction dredge 10.2 cm ( (4 inch)) suction and 3 inch (7.6 cm) discharge) in the Haynes Coastal Engineering Laboratory. The experimental results are compared to the results of a previously developed theory for estimating cutterhead forces. A MATLAB program is written and used to solve the theoretical equations. The sediment used in the study had a d50 of 0.27 mm and an angle of internal friction of 21.6°. The sediment is contained in the deep sediment pit 7.6 m (25 ft long), 3.7 m wide(12 ft ) and 1.5 m deep(5 ft) in the dredge/tow tank that is 45.7 m long(150 ft), 3.7 m wide(12 ft), and 3.0 m deep(10 ft). The objectives of the study are to calculate the forces using existing theory and MATLAB program and compare the theoretical results to those measured in the laboratory. The effects of the depth of cut, direction of swing, and cutter rpm on the forces acting on the cutter head are evaluated. The forces on the cutterhead are determined through the use of a set of six load cells rated at 13.3 kN (3000 lb). The load cell measurements allow direct calculation of the forces on the cutter head through the use of static equilibrium equations with the assumption of a constant swing speed. Once the forces are determined the results can be scaled to fit an actual dredge and then be applied in the determination of dredge design characteristics. The study shows the ability of the theory to determine the forces within an order or magnitude. The theoretical forces allow design of a cutter using a factor of safety. The variability of the forces in the laboratory study shows the assumption that the cutting forces are generally steady is not always valid.

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 109-111).

Thesis (M.S.)--University of North Carolina at Wilmington, 2003. / Includes bibliographical references (leaves : [69]-72).

The purpose of this thesis is to describe the three-dimensional velocity flow field measurements in the vicinity of the inlet mouth of a cutterhead suction dredge. Using acoustic Doppler velocimeters (ADVs), an accurate visualization of the velocity flow field was used to determine the region of influence around the cutterhead. Similitude is used in the experimental study to determine the correlation between the velocity flow field and other dredge parameters such as suction intake diameter without the cutterhead and with a rotating cutterhead. This is useful to the dredging community for two reasons: first, knowing the region of influence around the cutterhead helps the dredger achieve higher production by using a more efficient cutting depth and second, achieving similitude with the velocity flow field allows for more accurate model testing in the future. In order to help understand the more complex flow field around the cutterhead created by the cutting process, scenarios involving three different suction flow rates, three cutterhead rotation speeds, and two swing speeds, were investigated. Prior studies of the flow field around the cutterhead provided a means to predict the velocity at the cutterhead intake. The flow field studies herein provide an extension into three dimensions as well as a verification of the previous results. The highest velocities were found to occur nearest the cutterhead, specifically in the lower hemisphere of the cutterhead where the suction intake is located. The magnitude of these values greatly decreased with increasing distance from the cutterhead. In addition, the flow rate is shown to directly correlate to the velocity around the cutterhead. It was found that the region of influence was nearly symmetrical around the cutterhead, but the shape could more accurately be described as an ellipsoid. The volumes of the regions of influence ranged from 10 ft^3 (0.283 m^3) to 80 ft^3 (2.27 m^3) for the model dredge and from 2,250 ft^3 (63.70 m^3) to 17,000 ft^3 (481.40 m^3).

No description available.

No description available.

The Naples Bay Estuarine System, situated in southwest Florida, has undergone extensive modifications caused directly and indirectly by anthropogenic influences. These alterations include the substitution of mangrove-forested shorelines with concrete bulkheads, canalization of the watershed and along the bay shoreline, and navigational channel dredging. The system consists of northern Naples Bay, southern Naples Bay, and Dollar Bay, whose shorelines range from highly developed to undeveloped, respectively. This project explored the natural geological response of the system to these alterations using data from side scan sonar, sediment grab samples, and vibracores. In highly urbanized northern Naples Bay, benthic substrates consist primarily of muddy sands, with few oyster reefs. Southern Naples Bay and Dollar Bay, however, consist of coarser sediment, and are characterized by extensive mangrove shorelines and numerous oyster reefs. The impact of anthropogenic alterations has significantly shifted sediment distributions in northern Naples Bay from a coarser to a finer grained substrate. This shift has occurred to a lesser degree in southern Naples Bay, and Dollar Bay has not made this transition, due to the relative lack of anthropogenic modifications made to this part of the system.