984 resultados para Campbell.


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The Republic of Kiribati is a vast South Pacific island group with one of the largest exclusive economic zones (EEZs) in the world. Kiribati waters support a wealth of marine fisheries activities. These activities occur in oceanic, coastal and inshore environments and range from large, foreign, industrial-scale oceanic fishing operations to small-scale, domestic, inshore subsistence fisheries, aquaculture and recreational fisheries. Kiribati has developed a framework of domestic and international governance arrangements that are designed to sustainably manage its wealth of marine resources. The report provides background information for fisheries projects in Kiribati that aim to build food security, improve artisanal livelihoods and strengthen community engagement in fisheries governance. It provides information on the current status of Kiribati fishery resources (oceanic and coastal), their current governance and future challenges. Fish and fisher alike pay little heed to maritime boundaries and bureaucratic distinctions. This report covers both sides of the oceanic/coastal boundary because of the I-Kiribati communities’ interest in oceanic fisheries such as tuna and their heavy dependence on its fisheries resources for food security and economic development. The report focuses on two potential pilot sites for community-based fisheries management projects: North Tarawa and Butaritari.

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The potential use of YBa2Cu3C7as an active component in a magnetic bearing is being investigated. Measurements are being made of the load bearing capacity and related stiffnesses in comparison to predictions from the critical state model. Although the load bearing capacity is high and increases with the square of the magnetic field trapped the stiffness is low. We report on a novel design concept to overcome this problem. © 1995 IEEE

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Melt processed HTSC bulk samples usually show a high inhomogeneity. These inhomogeneities influence application-relevant properties such as the lévitation force or the trapped field. In this contribution a technique is presented which allows investigation of these inhomogeneous properties. The measurements are performed by scanning the sample surface with a small coil system and detecting the first and third harmonic of the inductive response. The critical current density jc is calculated from the measured signal using a modified critical state model. Jcdistributions yielded by this technique are shown. © 1997 IEEE.

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The potential use of YBa2j as an active component in a magnetic bearing is being investigated. Although the load bearing capacity is high and increases with the square of the magnetic field trapped, the stiffness is low. Both the stiffness and the lévitation height are a function of the loading history of the bearing. At Cambridge we have been investigating the effects of dynamic loading such as single large excursions from steady state loads and cyclically applied loads such as vibrations. Since a superconducting bearing has little inherent damping cyclic loads applied at or near its natural frequency can have catastrophic effects. The information being gathered at Cambridge will be used to enable these effects to be mitigated in the bearing design process. © 1997 IEEE.

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Axial and journal bearings have been investigated for use in superconducting flywheel systems. Our test rig comprises of an Evershed type magnetic bearing used to levitate a 35 kg rotor. The stabilizing forces are provided by superconducting axial and journal bearings. In this study we focus on the vertical stiffness measurements and explore the use of journal bearings. The journal bearing consists of radial magnets with alternating polarities. Our results indicate that this type of journal bearing can effectively stabilize the rotor. Spin-down test shows a linear behavior.