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Exhaust gas after treatment on medium-speed diesel engines
AuthorsU Hopmann
PublisherIMarE Conferences and Symposia
AbstractTests with a catalytic converter were carried out on MaK engines within the framework of the CLEAN project. The contaminant components of marine diesel engines are described and the ideas behind reducing emissions are discussed. The Siemens selective catalytic reduction (SCR) system used in the tests is described. The TT-Line ferry newbuilding Nils Dacke was used as a test ship for practical trials of the experimental SCR plant. Besides experience with gas oil operation on the MV Nils Dacke trials were also carried out on the MaK experimental test bed with an engine running on heavy fuel and an SCR catalyzer. Results are discussed and optimisation possibilities for future SCR exhaust gas cleaning plants are outlined.
AuthorsDate publishedU Hopmann
1999
PublisherIMarE Conferences and Symposia
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Green sea and water impact on FPSO: numerical predictions validated against model tests
AuthorsC T Stansberg ; O Hellan ; J R Hoff et al.
Date published2002
AbstractA recently developed numerical design method for analysis of green sea events and resulting impact loads on deck structures of FPSO's is validated against model test data. Steep irregular wave conditions are considered and numerical time series reconstructions are made using the measured wave as input. A second-order numerical random wave description is combined with standard 3D wave diffraction and related vessel motions to predict the relative wave kinematics. A modified shallow water formulation is applied for the prediction of the propagation on deck and resulting local pressures on the deckhouse are estimated by a similarity solution. Comparisons to the experiments are made for the relative wave amplitudes water propagation on deck and the resulting deck-house loads. Thus selected green sea events are investigated in detail and characteristics identified.
AuthorsC T Stansberg ; O Hellan ; J R Hoff et al.
Date published2002
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Hydrodynamics Aspects of the Sinking of the Ferry Herald of Free Enterprise Read in London at a meeting of RINA on 20 April 1988
AuthorsI W Dand
Shelf Location215d
AbstractThis paper reports on the investigation carried out by British Maritime Technology into the capsize and sinking of the passenger/ freight ferry `Herald of Free Enterprise'. The study concentrated on hydrodynamic aspects of the incident and involved a multidisciplinary approach using computer models physical models and a full-scale trial. Once sufficient water was on the deck stability was lost and the ship heeled and entered a severe turn due to yaw/heel coupling. Centrifugal effects aggravated the heel with the ship ultimately resting on her beam ends.
AuthorsDate publishedI W Dand
1989
Shelf Location215d
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Impact of a large-scale area closure on patterns of fishing disturbance and the consequences for benthic communities
AuthorsT A Dinmore ; D E Duplisea ; B D Rackham et al.
Date published2002
AbstractThe aim of this paper is to predict the effects of area closure on fishing effort distributions and the production of benthic communities. Also there is comparison of the effects of observed effort distributions with the effects of uniformly or randomly distributed effort on the same fishing grounds. It is determined how the spatial scale of analysis affects the results. The analyses focus on the response of the international beam trawl fleet to the cod box closure as assessed by satellite monitoring. A look is taken at methods covering study area estimates of trawling disturbance and effects on benthic production. Next results are considered. These are followed by discussion.
AuthorsT A Dinmore ; D E Duplisea ; B D Rackham et al.
Date published2002
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Influence of axial force on the vibration of Euler-Bernoulli beam structures solved by DQEM using EDQ
AuthorsChang-New Chen
Date published2005
AbstractThe analysis of influence of axial force on the vibration of Euler-Bernoulli beam structures is frequently necessary for modern engineering design. Numerical methods can be used to solve this vibration problem. An efficient method that can be used to develop a solution algorithm for this structural problem is DQEM (the differential quadrature element method). The influence of axial force on the vibration of Euler-Bernoulli beam structures is analysed by DQEM using EDQ (extended differential quadrature). DQEM uses the differential quadrature to discretise the governing differential eigenvalue equation defined on each element the transition conditions defined on the inter-element boundary of two adjacent elements and the boundary conditions of the beam. Numerical results solved by the developed numerical algorithm are presented. The convergence of the developed DQEM analysis model is efficient. The developed analysis technique can be used to solve more structural problems existing in the offshore field.
AuthorsChang-New Chen
Date published2005
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Investigation of draft effects on analysis of hydroelastic responses of pontoon-type VLFS
AuthorsSa Y Hong ; Yoon R Choi ; S W Hong
Date published2001
AbstractIn the present study effect of draft changes on hydro-elastic response of pontoon type VLFS is investigated mainly focusing on local response wave run-up along the waterline. Three dimensional higher-order boundary element method (Hong et al; 1999 Choi Hong and Choi; 1998) is extended to be able to generally treat hydrodynamic forces of elastic bodies (Newman 1994). Thin plate equation is used for representing elastic behaviours of the structure. Intensive numerical calculations are carried out for box type structures to investigate draft effect on elastic responses as well as hydrodynamic forces on pontoon type VLFS. Main attention is paid to wave run-up along the waterline for various cases of draft scantling.
AuthorsSa Y Hong ; Yoon R Choi ; S W Hong
Date published2001
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On the icebreaking forces and resistance of a ship advancing in level ice
AuthorsP Valanto
PublisherAmerican Society of Mechanical Engineers - ASME
AbstractThe icebreaking forces and resistance on the design waterline of a ship advancing in level ice have been studied with simple analytical and numerical models to shed light on the dependency of icebreaking forces on the local angles at the waterline. The influence of compressive membrane stresses in the ice cover were studied as the flexural stresses are reduced which postpones the ice cover failure at the waterline of the advancing ship causing additional resistance. With higher ship speeds the in-plane forces gain further importance as the fluid foundation of the ice cover becomes harder; the development of the flexural stresses but not the membrane stresses are slowed. This breaking mechanism has relevance both to icebreaking resistance and to the ice loads on the ship hull and should be included in numerical models describing the icebreaking process at the waterline.
AuthorsDate publishedP Valanto
1997
PublisherAmerican Society of Mechanical Engineers - ASME
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On the occurrence of strong higher harmonic wave forces and induced ringing loads on vertical cylinders
AuthorsJohn Grue ; Morten Huseby
Date published2002
AbstractExperimental observations of a secondary load cycle in the force acting on a vertical cylinder exposed to long and steep waves are considered. A complementary discussion of the occurrence of ringing of models of offshore structures is given. The paper summarizes the occurrence of pronounced higher harmonic forces observed in wave tank experiments in periodic waves the leading transient part of a wave group focussing waves and irregular waves. Results from other scientific groups are collected and compared with the measurements made at the University of Oslo. The paper also includes the main findings of a larger investigation.
AuthorsJohn Grue ; Morten Huseby
Date published2002
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Strength of New-Type Steel Plate Having Surface Layers With Ultrafine Grain Microstructure
AuthorsT Ishikawa ; T Koseki ; Y Hagiwara et al.
Date published2001
AbstractThe effects of ultra-fine grain microstructure on fracture toughness and fatigue strength in air and artificial seawater are investigated. SUF steel plates have superior fatigue properties both in air and seawater. Especially the shape and depth of corrosion pits formed on the surface of the SUF region in the seawater fatigue test were completely different from those on conventional microstructures. Inner surfaces of corrosion pits on SUF microstructure were smoother than those on conventional microstructure and depth of corrosion pits on SUF microstructure were shallower than those on conventional microstructure. Therefore the fatigue strength Of SUF in seawater is better than that of conventional microstructures.
AuthorsT Ishikawa ; T Koseki ; Y Hagiwara et al.
Date published2001
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Stress path pore pressure and microstructural influences on Q in Carnarvon Basin sandstones
AuthorsA F Siggins ; D N Dewhurst ; P R Tingate
Date published2001
AbstractUnderstanding the dependence of velocity and attenuation on confining pressure and pore pressure in reservoir sandstones is vital both for extracting subsurface dynamic elastic parameters from seismic data and also for relating laboratory measurements to larger scale lower frequency data. The influence of pore pressure on velocity and attenuation is of obvious interest to the oil industry as the ability to predict overpressure and lithology pre-drill can have significant impact on well costing. Triaxial loading combined with ultrasonic testing is carried out on two Carnarvon Basin reservoir sandstones from the Australian Northwest Shelf. Results are explained and presented graphically.
AuthorsA F Siggins ; D N Dewhurst ; P R Tingate
Date published2001
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Study of the impact of marine lubricants additive chemistry on adhesive wear scuffing and corrosive wear - relationship between neutralisation speed measured by NAMO and corrosive wear
AuthorsJ-Ph Roman ; C Foin ; K Hosonuma et al.
Date published2001
AbstractIn modern marine diesel engine operation the tendency is to increase the power the PME (mean effective pressure) and the piston speed while reducing the fuel and lube oil consumption. This has a great impact on cylinder lubricant performance requirements especially in the very large bore and long-stroke crosshead engines. However as pressure increases so lubricant film thickness reduces and the time of exposure to combustion is extended. This increases the probability of adhesive wear and scuffing. In addition as HFO (heavy fuel oils) contain high amounts of sulphur corrosive wear can remain depending on the engine condition. New test methods on pin-on-disc tribometers are developed which can describe adhesive wear
AuthorsJ-Ph Roman ; C Foin ; K Hosonuma et al.
Date published2001
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Study on building local marine geomagnetic field model based on interpolation method
AuthorsJianhu Zhao ; Hui Liu ; Juanjuan Li
Shelf Location214b
AbstractGeomagnetic navigation based on a geomagnetic field model is an autonomous navigation which is very useful for the activity of underwater vessels. Geomagnetic navigation can provide real-time positioning information by matching geomagnetic observation data and geomagnetic background map or LGFM (local geomagnetic field model). A very important factor which restricts the accuracy of geomagnetic navigation is the accuracy of LGFM. The primary difference between local normal geomagnetic field modelling and global geomagnetic field modelling is the number of observation points and the building model methods. Usually polynomial surface method is adopted in building LGFM rather than spherical harmonic analysis because LGFM does not have 3D meaning. Although the polynomial surface method is simple and convenient it is difficult to achieve satisfying model accuracy in actual applications. In order to obtain high-accuracy LGFM to serve underwater geomagnetic navigation two typical surface interpolation methods are studied: SSF (spine surface function) and MSF (multi-surface function). The two methods are described in detail and conclusions and recommendations are drawn.
AuthorsDate publishedJianhu Zhao ; Hui Liu ; Juanjuan Li
2008
Shelf Location214b
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Study on possibility for monitoring of marine diesel engine wear condition
AuthorsTakaaki Hashimoto ; Senichi Sasaki
Date published2004
AbstractCBMS (condition-monitoring-based survey) is now available on propeller shaft and bearing metal on board ships under some conditions. However a surveyor must inspect the lubricating surfaces of a diesel engine every 5 years. This can be called a 'time-based survey'. The possibility of using a CMBS for ship diesel engines is investigated. One trial the combination test of an acoustic emission analysis and cylinder drain oil analysis was done on board a sailing ship and the results were reported in 2002 at a marine symposium. The other trial analysing oil containing foreign metal wear particles is considered here. Two foreign metals (cobalt and yttrium) were embedded in piston ring test piece and another foreign metal (barium) in a white metal test piece. PDWT (pin on disk wear tests) were run by a private wear test machine. The first wear test was run for 180 hours under an oil temperature of 160 ºC and a load of 5000 N. The second wear test was run for 97 hours under an oil temperature of 100 ºC and a load 3500 N. The oil in service was analysed by a spectrometric oil analysis program and a ferrography analysis method.
AuthorsTakaaki Hashimoto ; Senichi Sasaki
Date published2004
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The Influence of Wave Grouping on Wave Height Distribution
AuthorsA D Velcheva ; Z I Cherneva
Date published1998
AbstractWave groups a finite run of higher than normal waves are often observed at sea and in the wave records. The wave group phenomena have an important impact on a wide range of ocean and coastal activities and should be taken into account for sophisticated design of deep water and coastal structures. Here the effect of wave grouping on the wave height distribution was investigated on the basis of field data. Field observations were conducted at the Research Station “Shkorpilovtzi” in the Institute of Oceanology - Bulgarian Academy of Sciences. The tendency that wave height distribution becomes wider as the degree of wave grouping is higher is examined. The problem of suitable wave group parameters which can present the influence of wave group structure on probability density function of wave heights is also discussed.
AuthorsA D Velcheva ; Z I Cherneva
Date published1998
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A guide to the Offshore Installations (Safety Case) Regulations 1992: guidance on regulations
AuthorsHealth and Safety Executive
Shelf Location227c
AbstractThis publication provides guidance on the Offshore Installations (Safety Case) Regulations 1992. After the introduction, the text of each regulation and schedule is given in italics followed by guidance on it. A concluding section of the publication sets out more detailed guidance on the preparation of safety cases as required under the Regulations. The primary aim of the Regulations is to reduce risks to the health and safety of the workforce employed in offshore installations or in connected activities.
AuthorsPublisherHealth and Safety Executive
London : HMSO, 1992.
Shelf LocationDate published227c
1992
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A laboratory simulation of wet icing build-up on H V insulators
AuthorsM Farzaneh ; J-L Laforte
Date published1997
AbstractA practical laboratory method is proposed to simulate wet atmospheric ice accretion on HV insulators. The method is based on first accumulating a low density soft rime on energized insulators and then heating the produced deposits. The liquid water fraction of the ice accretion is determined using a centrifuge. The performance of insulators under wet snow-like conditions with relatively low cost equipment can be determined.
AuthorsM Farzaneh ; J-L Laforte
Date published1997
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A risk-based approach for the evaluation of fire & safety equipment on liquefied gas jetties
AuthorsR J Roue
Date published1998
AbstractThe development of a document in which quantitative risk assessment (QRA) is used to determine the effectiveness and requirements for fire fighting equipment on jetties has been carried out by AEA Technology on behalf of SIGTTO. Objectives theoretical background and the principles of QRA are explained and a simplified overview of the risk based approach for the evaluation of fire and safety equipment on LPG jetties presented.
AuthorsR J Roue
Date published1998
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An investigation of ballast water management methods with particular emphasis on the risks of the sequential method
AuthorsLefteris Karaminas
Shelf Location226b
AbstractThe objectives of this study on ballast water management are: to investigate the effects of the one of the IMO ballast water exchange at sea methods, the sequential method, on the ship’s structure and the assessment criteria in respect of classification, statutory and operational aspects; and to develop a safe operational envelope, on the basis of sea-keeping analysis, to control the dynamic effects for the ballast condition under consideration.
AuthorsPublisherLefteris Karaminas
Lloyd's Register
Shelf LocationDate published226b
2000
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Changing technologies - implications for personnel on naval platforms
AuthorsL A Kemp ; Colin Corbridge ; A O'Shea
PublisherIMarE Conferences and Symposia
AbstractWork conducted by the Defence Evaluation and Research Agency (DERA) Centre for Human Sciences (CHS) to examine the effects of lean manning and increasing technology on the Royal Navy (RN) organisation is described. First a look is taken at skill requirements platform organisation and branch structure problems. After this two studies carried out to investigate the impact of new technology on the personnel organisation on a frigate sized naval platform are described and discussed.
AuthorsDate publishedL A Kemp ; Colin Corbridge ; A O'Shea
2000
PublisherIMarE Conferences and Symposia
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Climate change and its effects on coastal management
AuthorsAlan H Brampton
Date published1996
AbstractThe observed or deduced changes in both the hydraulic and sedimentary regime of the UK coastline is examined and some case histories are presented. After some introductory information attention is given to effects on coastal management in view of recorded climatic changes and the widely expected continuation of global warming. Next a look is taken at effects of changes in wave climate including impacts on man-made defences and impacts on beaches. This is followed by consideration of other effects covering rainfall changes in winds and temperatures in water temperature.
AuthorsAlan H Brampton
Date published1996