The concepts of floating structure plays a very important role in deepwater projects; and the design of the floating structure is one of the most important tasks in the project. The importance of the floating structur...The concepts of floating structure plays a very important role in deepwater projects; and the design of the floating structure is one of the most important tasks in the project. The importance of the floating structure in offshore projects can be demonstrated in the following several areas： the substantial dynamic structure responses due to wave loading and current loading; the limited motion requirements of risers in deep water; and the increasing difficulty of installation for different components of the system. Three major technical aspects have to be considered, i.e. the strength of structure, the fatigue resistance capacity of the system, and local and global stability of the structure. This paper reviews the current design practice of floating structures, evaluates the main tasks during the design and associated major technical requirements, and addresses the major technical challenges encountered during the design. As a close-out of the paper, the authors discuss some potential future developments in the design of floating structures.展开更多
The step load response of reciprocating engines is one of the key characteristics when considering its application in medium to large scale stationary power generation especially with islanded generation. This paper d...The step load response of reciprocating engines is one of the key characteristics when considering its application in medium to large scale stationary power generation especially with islanded generation. This paper discusses the impacts of power frequency deviation on the generators and electrical equipment in the network and presents the relationship between step load capabilities and generator operating parameters. For a power plant consisting of a number of generators both step load and power output requirements must be satisfied. An analysis method is proposed to facilitate the development of an operation strategy which can meet both step load and power demand requirements in the full load range.? Typical reciprocating engine step load curves are used to demonstrate the analysis method and the results are further optimised for lower operational cost. This analysis method provides a general approach to operation strategy of large reciprocating engines used in islanded power generation.展开更多
Geologists can offer key insights in regard to several high profile environmental issues that are faced today. At the same time, like scientists in most other disciplines, many geologists are not naturally adept at co...Geologists can offer key insights in regard to several high profile environmental issues that are faced today. At the same time, like scientists in most other disciplines, many geologists are not naturally adept at communicating in an effective manner with non-geologists. This paper firstly identifies the more subtle facets of topical major issues （the drivers） where geologists can contribute important perspectives. Next, the detractions to effective communication are identified, along with the recommended means to overcome them （the mechanisms）. Many topical issues are in fact geologically-underpinned （e.g. obviously, geohazards）, so geologists ought to have something meaningful to say. By the same token, if geologists have difficulty communicating with other scientists, how can they possibly hope to communicate with journalists and with the public at large？ Proper scientific contextualization is an ideal starting point, but this fundamental framing step does not always suit protagonists who have non-scientific agendas. Thus, geologists not only have to convey their science （geology） in an understandable way, but to do so in a truly effective manner must recognize and take into account possible predispositions that their audience may have.展开更多
Dredging plume dispersion studies, use dredging plume models to predict the fate of sediment plumes resulting from dredging activities and dredge spoil disposal. The model results are applied as input to environmental...Dredging plume dispersion studies, use dredging plume models to predict the fate of sediment plumes resulting from dredging activities and dredge spoil disposal. The model results are applied as input to environmental impact assessment of the proposed dredging, particularly those associated with suspended sediments and sedimentation. Model validation and performance are still not resolved because of the difficulty of site measurements and the understanding of the parameters used in the model. This paper presents a 3-D dredging plume model based on the MIKE3 software package to investigate parameters which affect the model performances. As a result of lack of site data for the public domain uses, the model scenarios are designed artificially for sensitive runs to identify the key parameters affecting plume behaviours. The factors include dredging spill rates using different dredging methods, equipment and sediment settling velocities. The influence of wave and wind effects combined with tidal forces on the sediment re-suspended rates and the advection/dispersion scales are also assessed.展开更多
基金Supported by China National 111 Project Under Grant No.B07109
文摘The concepts of floating structure plays a very important role in deepwater projects; and the design of the floating structure is one of the most important tasks in the project. The importance of the floating structure in offshore projects can be demonstrated in the following several areas： the substantial dynamic structure responses due to wave loading and current loading; the limited motion requirements of risers in deep water; and the increasing difficulty of installation for different components of the system. Three major technical aspects have to be considered, i.e. the strength of structure, the fatigue resistance capacity of the system, and local and global stability of the structure. This paper reviews the current design practice of floating structures, evaluates the main tasks during the design and associated major technical requirements, and addresses the major technical challenges encountered during the design. As a close-out of the paper, the authors discuss some potential future developments in the design of floating structures.
文摘The step load response of reciprocating engines is one of the key characteristics when considering its application in medium to large scale stationary power generation especially with islanded generation. This paper discusses the impacts of power frequency deviation on the generators and electrical equipment in the network and presents the relationship between step load capabilities and generator operating parameters. For a power plant consisting of a number of generators both step load and power output requirements must be satisfied. An analysis method is proposed to facilitate the development of an operation strategy which can meet both step load and power demand requirements in the full load range.? Typical reciprocating engine step load curves are used to demonstrate the analysis method and the results are further optimised for lower operational cost. This analysis method provides a general approach to operation strategy of large reciprocating engines used in islanded power generation.
文摘Geologists can offer key insights in regard to several high profile environmental issues that are faced today. At the same time, like scientists in most other disciplines, many geologists are not naturally adept at communicating in an effective manner with non-geologists. This paper firstly identifies the more subtle facets of topical major issues （the drivers） where geologists can contribute important perspectives. Next, the detractions to effective communication are identified, along with the recommended means to overcome them （the mechanisms）. Many topical issues are in fact geologically-underpinned （e.g. obviously, geohazards）, so geologists ought to have something meaningful to say. By the same token, if geologists have difficulty communicating with other scientists, how can they possibly hope to communicate with journalists and with the public at large？ Proper scientific contextualization is an ideal starting point, but this fundamental framing step does not always suit protagonists who have non-scientific agendas. Thus, geologists not only have to convey their science （geology） in an understandable way, but to do so in a truly effective manner must recognize and take into account possible predispositions that their audience may have.
文摘Dredging plume dispersion studies, use dredging plume models to predict the fate of sediment plumes resulting from dredging activities and dredge spoil disposal. The model results are applied as input to environmental impact assessment of the proposed dredging, particularly those associated with suspended sediments and sedimentation. Model validation and performance are still not resolved because of the difficulty of site measurements and the understanding of the parameters used in the model. This paper presents a 3-D dredging plume model based on the MIKE3 software package to investigate parameters which affect the model performances. As a result of lack of site data for the public domain uses, the model scenarios are designed artificially for sensitive runs to identify the key parameters affecting plume behaviours. The factors include dredging spill rates using different dredging methods, equipment and sediment settling velocities. The influence of wave and wind effects combined with tidal forces on the sediment re-suspended rates and the advection/dispersion scales are also assessed.
