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VanZwieten, J.H. (Florida Atlantic University) | Baxley, W.E. (Florida Atlantic University) | Alsenas, G.M. (Florida Atlantic University) | Meyer, I. (Stellenbosch University) | Muglia, M. (University of North Carolina) | Lowcher, C. (University of North Carolina) | Bane, J. (University of North Carolina at Chapel Hill) | Gabr, M. (North Carolina State University) | He, R. (North Carolina State University) | Hudon, T. (PCCI) | Stevens, R. (Fugro-McClelland Marine Geosciences) | Duerr, A.E.S. (New West Technologies)
To assist in the development of mooring and foundation solutions for ocean current based electricity production, an overview of the resource and seafloor characteristics in three potential power production regions are presented. These regions are offshore Florida USA, North Carolina USA, and South Africa. Maximum measured flow speed off both the USA and South Africa were around 3.0 m/s and maximum temporally averaged energy densities were between 2.0 - 3.0 kW/m2. Water depths at considered locations range from 60-400 m, and bottom type varies greatly. Most evaluated locations contain occasional flow reversals and occasions when current speed approached 0.0 m/s (only locations near the core of the Gulfstream off SE Florida did not measure either event). While low current events are undesirable from energy production and mooring design perspectives, they might provide unique opportunities to install or maintain equipment.
A three-dimensional in-house transient computational code ITU-WAVE based on panel method, potential theory and Neumann-Kelvin linearization is extended to take into account wave interaction in an array system using two and four truncated vertical cylinder arrays. ITU-WAVE transient fluid-structure interaction panel code is validated against analytical array results before applied to power absorption from ocean waves for different array configurations. The effects of the separation distances between array system and heading angles on energy absorption in both sway and heave modes are studied by the support of numerical simulations which show sway mode has wider bandwidth than heave mode for energy absorption. It is also shown wave interactions are stronger when the array systems are close and these wave interactions are reduced significantly and shifted to larger times when the separation distance is increased. The wave interaction is much stronger at the same separation distance and heading angle in heave mode than in sway mode. Numerical experience also shows that more power is absorbed in sway mode than heave mode in both two and four array systems at any separation distances and heading angles when the bodies in array system have the same displacement in both sway and heave modes.
INTRODUCTION In the 1970s, the four international consortia based in the United States and Canada started deep-ocean mining R & D from "zero-base knowledge on 5,000-m-range deep ocean floor," when 100-m depth was called "deep water." Among the four consortia, Ocean Minerals Company (OMCO) started its deep ocean mining program in 1975. The operating company was Lockheed Missiles & Space Co. Inc. ("Lockheed"). OMCO successfully deployed the world's most advanced deep ocean mining system from the Hughes Glomar Explorer ("Explorer") with a 5,000-m steel pipe, a buffer at its bottom end, buffer-link-(remotely controlled) oceanfloor miner with Archimedeanscrew propulsion and collector in the North Pacific Ocean.
Development of deep ocean hydrothermal poly-metallic ore mining is a highly anticipated industry in Japan to increase self-sufficiency of metals and bring economic benefits, however there are many issues still to be clarified, including waste disposal and its economic feasibility impact. This paper examines the current applicable regulations in Japan to understand what the potential barriers and problem waste elements may be. The results show that waste water treatment under three different sets of regulations may require at least 99.9% removal of As, Hg and suspended solids from the slurry before it is released.