Installed 160 miles South of New Orleans in 1300 m of water, the Marco Polo Tension Leg Platform is subjected to an extensive monitoring campaign to benchmark design data and methods. The purpose of the full scale monitoring campaign is to evaluate the design in operation exposed to hurricane and loop-current conditions. Interests comprise the high and low frequency modes of motion, the fatigue loading of the platform and the dynamic behavior of the tendons and risers with focus on vortex induced vibrations. To evaluate these results wind, wave and current conditions are closely monitored. Figure 1: Marco Polo TLPThe monitoring system was in operation during the passage of hurricanes Ivan, Katrina and Rita. Although Marco Polo was extremely close to the center of these severe hurricanes, no significant damage was inflicted to the platform, even though wind speeds in excess of 138 mph and maximum wave heights over 28 m were measured. However, very valuable data was collected on the wave, wind, current, as well as on the response of the TLP during the Hurricane conditions.
The challenging development of new platform concepts and their installation in deeper water in more remote areas and more severe weather conditions require a direct feedback from offshore experience to design and engineering. Moreover the platform operation itself can be enhanced by utilizing the actual behavior of the platform and its environmental conditions.
The hull forms used for FPSOs and trading tankers look very similar. So similar in fact that it may appear that one could use the same design and design methods for both vessels. Both vessels will be subject to extreme and fatigue loading and both will have a similar design life. But each will have different design requirements and therefore different designs.The trading tanker spends most of its life moving oil from one location to another, in either one of two draft conditions, ballast or laden. They are dry-docked at regular intervals for maintenance, inspection and if necessary repair.FPSOs are stationary, i.e. they have zero forward speed, the vessel's draft is continuously changing, the maintenance and inspection is done in situ, and they are not usually dry-docked.These apparently subtle differences, see Table 1, in design requirements are not so subtle with respect to the load differences, both short term and long term for the two designs. This difference is the driver for the FPSO Integrity Joint Industry Project.The JIP was established to obtain fatigue load information on an FPSO through full-scale measurements. The main goals were as following.• Develop of a computational model for fatigue loading • Evaluate current practice.• Have the Classification Societies conduct a comparative study, and • Recommend a fatigue method for use in design of FPSOs.The work in this JIP is being further enhanced through a sister JIP "FPSO Fatigue Capacity" being administered by DnV. By combining the results of the two JIPs, the industry is gaining a better knowledge of the fatigue loads and fatigue resistance on FPSOs. Predictive methods are being developed to calculate the fatigue lifetime of FPSOs and this is leading toward more reliable systems.
We report about a patient with polyarticular rheumatoid arthritis taking methotrexat and 5 mg prednisolone who developed in the course of a RA flare a septic arthritis in the right shoulder. Listeria monocytogenes could be identified as the causative bacteria. Clinically, the Listeria-induced septic arthritis could not be differentiated from rheumatoid arthritis; fever was not present. The synovial analysis showed a granulocytic effusion with 19,000 cells/ml; there was no microbiological growth within the first 24 hours. Only the low glucose level indicated a possible septic arthritis. After 48 hours, gram-positive bacterial growth was evident and Listeria monocytogenes could be isolated after 72 hours. Therapy was initiated by antibiotic treatment and arthrotomy with synovectomy followed by extensive irrigation which proved effective in bacterial elimination but joint destruction resulted. During the whole course, Listeria antibodies were negative and proved to be too insensitive. The incidence of Listeria-induced arthritis is very low; a review of the literature revealed only 24 reported cases. It occurs primarily in patients with rheumatic diseases under immunosuppression and in prosthetic joints. The diagnosis is based on cultural detection. It is important to cultivate synovial effusions for longer than 24 hours in order to identify Listeria. This is of relevance since Listeria serology is not sensitive.
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