查看更多>>摘要：The International Maritime Organization (IMO) has been discussing technical issues by dividing the second-generation intact stability criteria for ships into five types. In this paper, we paid attention to the dead ship condition and introduced the process for the assessment of Levels 1 and 2 in detail. Dead ship condition refers to a case where a large angle of rolling motion occurs due to waves incident on the side of the ship's hull after the ship's engine has failed. Basically, in the dead ship condition, if the Level 1 criterion for analysis related to the GZ curve is not satisfied, an evaluation is performed against the Level 2 criterion considering the hydrodynamics of waves. The method for the effective wave slope function required to obtain the spectrum of the effective relative roll angle, which is the most important factor in the calculation of Level 2, was implemented. In particular, unlike existing ship types in terms of various experiences, this study performed stability evaluation using special ship data of a 5000HP tug boat and obtained results that satisfied both Level 1 and 2 standards. Through this example of dead ship condition evaluation for a tug boat, we aim to ensure the expansion of IMO second-generation intact stability evaluation targets for various types of ships.
Fabio Gouveia Telles de MenezesFabricio Nogueira CorreaBreno Pinheiro Jacob
194-217页
查看更多>>摘要：This work describes an offshore gas monetization solution for harsh environmental conditions at ultra-deepwater and remote locations, as an alternative to conventional onshore plants associated with long subsea pipelines for Greenfield projects. Although gas-to-liquids and marine compressed natural gas are initially evaluated, associated gas is supposed to be exported from deepwater floating production storage and offloading units to a central floating liquefied natural gas (FLNG) facility for additional treatment, fractionation, and liquefaction, producing liquefied natural gas (LNG) and liquefied petroleum gas (LPG) for further tandem offloading. To demonstrate the technical feasibility of the proposed FLNG, its key technologies are reviewed, including liquefaction process selection, cargo containment system, station-keeping, offloading, and power generation. A full-electric FLNG is proposed, replacing conventional feed gas power generation systems with inner hull nuclear power modules, envisaging neutral CO_2 emissions and earlier first LNG drop milestone achievement. The FLNG general arrangement is developed, along with its internal cargo tanks layout, for preliminary LNG and LPG production rundown and feed gas throughput. Numerical analyses are carried out to show that static and dynamic tilt criteria can be met, even for harsh sea states. Gas import riser configurations for the challenging ultra-deepwater location are outlined, after appropriate FLNG station-keeping analyses, in addition to a feasibility assessment of seawater intake risers, aiming for an overall gas plant efficiency increase.
查看更多>>摘要：The paper presents a novel approach of cooperative multiagent reinforcement learning (CMARL) combined with A* search to address ship multicabin equipment layout considering pipe route, aiming to minimize pipe cost while considering practical requirements. The formulation is established through equipment simplification and grid marking, and A* search is utilized to value the pipe route. By designing equipment states, the equipment layout in each cabin is solved using a CMARL approach that involves three actions. Subsequently, comparative experiments were conducted on an engine room case by CMARL against genetic algorithm and single multiagent reinforcement learning methods under the condition of coupling with A* search. The parameter values for these methods were sampled using Latin Hypercube. The findings demonstrate that CMARL has superior combination properties.
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