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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

A Bezier based higher order panel method for steady flow analysis of lifting and non-lifting bodies

Roessler, Edmund B. (Edmind Brian), 1963- January 2001 (has links)
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2001. / Includes bibliographical references (p. 81-84). / by Edmund B. Roessler. / S.M.
42

Optimization of an advanced high speed hull form

Zajic, Henri W. (Henri William) January 1995 (has links)
Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1995. / Includes bibliographical references. / by Henry W. Zajic. / Nav.E.
43

The effectiveness and economic impact of enhancing container security

Dresser, Eric L. (Eric Lane) January 2004 (has links)
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2004. / Includes bibliographical references (p. 96-101). / Over the past few decades, international containerized shipping has evolved to become the main artery of global trade, providing both convenient and inexpensive access to goods from markets around the world. Yet the very size and efficiencies that have made container shipping such an attractive means of transport have also created a system that is highly vulnerable to terrorist exploitation. This paper outlines the current initiatives taken by both the public and private sector to address the security vulnerabilities in the container industry. The solution targets three main areas for, security: documentation/information, physical security, and inspections. The technology utilized to improve the physical security of the container can also be used to track shipments and secure the container from pilferage. This generates a win-win relationship between enhancing container security while improving supply chain information and control. An economic model is used to demonstrate the cost savings and cost avoidance from the information and control provided by security technologies. The savings to shippers more than offsets the cost of implementing these technologies. This is a valuable approach to solving the problem of container security because it concurrently provides incentive to the private sector and protects global interests. / by Eric L. Dresser. / S.M.
44

The forward speed diffraction problem in following seas

Osborne, Gregory E., 1964- January 1994 (has links)
Thesis (Ocean. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1994. / Includes bibliographical references (p. 97-99). / by Gregory E. Osborne. / Ocean.E.
45

A comparison of experimental and theoretical sail forces

Klein, Andreas Kirschmer January 1990 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1990. / Includes bibliographical references (leaves 69-70). / by Andreas Kirschmer Klein. / M.S.
46

Navier-Stokes simulations of steep breaking water waves with a coupled air-water interface

Hendrickson, Kelli L January 2005 (has links)
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2005. / Includes bibliographical references (p. 367-378). / Wave breaking on the ocean surface significantly facilitates the transfer of mass, momentum, heat and energy across the air-sea interface. In the context of the near field flow about a surface ship, the breaking bow wave is a key element to the bubbly signature and an appreciable portion of the wave drag of the ship. Yet, despite its direct effect on many aspects of ocean engineering, this phenomenon is not well understood even at a basic level. Most of the knowledge has been contributed by experiments in the laboratory and the field although results are often limited due to the difficulty in taking measurements of local quantities during the breaking event. Numerical solution of the breaking wave problem has generally been limited to the pre-breaking phase as it avoids complex mechanisms such as surface re-entry, spray formation, air entrainment and strong turbulence. Additionally, relatively few experimental or numerical studies exist which dynamically couple the air-water interface. The objective of this thesis is to contribute to the knowledge of steep breaking waves in the context of the coupled air-water interface. Of central importance are basic kinematics and dynamics, the rate of energy dissipation and energy flux at the interface during the breaking event. / (cont.) To this end, a systematic study of a range of breaking waves is performed by direct numerical simulation (DNS) of the Navier- Stokes equations using an Eulerian interface capturing method. The advantage of the DNS approach is that all physical scales are resolved and no turbulence closure models are necessary. However, because of this, DNS is limited to the study to moderate Reynolds numbers with a relatively high computational cost for each simulation. For this reason, this study is limited to two-dimensional flows at Reynolds number 0(10³). The interface capturing method used is a modified form of the level set method which is better suited for simulating coupled air-water flows. The level set method provides a natural numerical treatment of the coupled air-water interface through complex surface topology changes. Thus, no ad-hoc treatment of the air-water interface during the breaking event is necessary. The key findings of this thesis represent new contributions to the study of breaking waves in three distinct areas. The first is the kinematics and dynamics of deep water breaking waves for both spilling and plunging types. For the waves in this study, there was no indication of flow reversal or separation in the water while the air flow showed separation on the front face of the wave and over the crest. / (cont. ) Localized shear regions are found in spilling breaking waves and curvature effects are identified as the dominant mechanism of vorticity generation in both types of breaking waves. The second area is the energy dissipated by breaking waves. The volumetric dissipation rates as well as its spatial variation for both air and water are presented for the range of waves in this study. While the water volume experienced an increase in dissipation rate during the breaking event, the increase is more pronounced in the air volume to the point that it becomes the same order of magnitude as that in the water for some waves. The amount of energy in the wave lost due to breaking is quantified as a function of the energy in the wave prior to breaking. A threshold below which waves do not break is identified and qualitative comparisons to experiment are made when applicable. The third area is the transfer of energy at the air-water interface during breaking which is an aspect of the breaking process that has not received much attention in the literature. In this thesis, the formulation of a term in the energy equation which accounts for the energy flux rate at the air-water interface is presented. The waves in this numerical study give evidence that this quantity is appreciable. / (cont.) Although the calculation of this term is sensitive to errors associated with the conservation of energy, values as high as 25% of the energy lost to breaking are found. At the Reynolds numbers in this study, the dominant mechanism for each type of wave is identified as inviscid for spilling breaking waves and viscous for plunging breaking waves. This numerical effort has contributed to the basic knowledge of wave breaking at moderate Reynolds numbers. Through the inclusion of the coupled air-water interface, unique insight to the kinematics, dynamics, dissipation and energy fluxes of breaking waves was obtained. The information gained in this study provides an initial step towards physics-based turbulence models for the study of wave breaking at larger scales. / by Kelli L. Hendrickson. / Sc.D.
47

Preliminary design and analysis of propulsors for axisymmetric underwater vehicles

Taylor, Todd Eric January 1996 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1996. / Includes bibliographical references (leaves 211-217). / by Todd E. Taylor. / Ph.D.
48

Fisheries management and flags of convenience / Flags of convenience and environmental impact

Papaioannou, Maria Andriana January 2004 (has links)
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2004. / Page 123 blank. / Includes bibliographical references (p. 105-107). / The over-exploitation of the world's fish resources and the depletion of many fish stocks have brought into focus the need for effective fisheries management and conservation measures. Many states have adopted international instruments or have participated in regional conservation committees to regulate and control fishing activities within their jurisdiction as well as on the high seas. However, compliance with the provisions of the fishery laws has been limited and as fishing restrictions increase, more incidents of illegal, unregulated and unreported (IUU) fishing activities are being reported. IUU fishing is facilitated by the use of flags of convenience (FOC), which enable fishing vessel owners to escape regulations, and often avoid liability for their actions. Many measures have been introduced and many existing laws have been reinforced to address the implications of FOCs in effective fisheries management. However, the FOC fishing fleet continues to increase, indicating that there are flaws in the current regulatory scheme. The objective of this thesis is to identify those flaws by examining both the conservation regime for fisheries as well as the role of FOCs in the world's fish trade, rather than focusing solely on their negative impact. / (cont.) By studying the rationale for the decisions of all participants in the fishing industry, from lawmakers, to major traders, we conclude that increasing transparency and flag state responsibility, although necessary, will not eliminate IUU fishing. FOCs are not the driving force for illegal fishing; on the contrary, they are the means to serve the purpose, which in this case is the satisfaction of high demand for high-valued scarce fishery resources. / by Maria Andriana Papaioannou. / S.M.
49

Improving performance of intermodal terminals through automation and rail-for-truck modal switch

Denisis, Athanasios, 1970- January 2002 (has links)
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2002. / Includes bibliographical references (leaves 94-97). / by Athanasios Denisis. / S.M.
50

Inversion of acoustic zooplankton measurement for adaptive physical-biological ocean forecast

Renard, Bertrand, 1977- January 2003 (has links)
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2003. / Includes bibliographical references (leaves 66-68). / by Bertrand Renard. / S.M.

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