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Ice loads on a model podded propeller blade in milling conditions
AuthorsJungyong Wang ; Ayhan Akinturk ; Stephen J Jones et al.
Date published2005
AbstractPropeller-ice interaction experiments were conducted in the ice tank at the National Research Council of Canada's Institute for Ocean Technology. A podded propeller was used in "Puller" mode and loads on an instrumented blade were measured. During the propeller-ice interaction hydrodynamic loads and ice milling loads were acting on the propeller blade. This paper focuses on the ice milling loads both in water and in air. The non-dimensional ice milling loads including inseparable hydrodynamic loads on the blade are presented against advance ratio with varied depths of cut. The results help to reduce the gap of knowledge for interaction between ice and propeller and give information about significant variables acting on the propeller blade during interaction.
AuthorsJungyong Wang ; Ayhan Akinturk ; Stephen J Jones et al.
Date published2005
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Impurity effects on pore formation at Al2O3-alloy interfaces
AuthorsP Y Hou
Date published2003
AbstractThe adhesion of Al2O3 scales on commercial grade alloys that do not contain a reactive element is usually poor due to the presence of 10-50 wppm of sulphur impurity and-or of pores that formed at the scale-alloy interface. The effect of impurities on pore nucleation and growth is evaluated. Sulphur in the alloy as well as possible surface contaminates are considered. Sulphur is usually believed to segregate to the interface to weaken the interfacial bonding and to stabilise interfacial pores. By using field emission scanning Auger microscopy the distribution of sulphur on pores and on oxide-imprinted areas at Al2O3-FeAl interfaces is precisely determined. Interfacial pore growth as a function of oxidation time was obtained from SEM (scanning electron microscopy) and AFM (atomic force microscopy) analyses. The effects of sulphur segregation surface impurity and reactive elements on pore nucleation and growth are discussed.
AuthorsP Y Hou
Date published2003
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Maritime traffic effects on biodiversity in the Mediterranean Sea : Volume 2 - legal mechanism to address maritime impacts on Mediterranean biodiversity
Authorseditors: Nilufer Oral ; Francois Simard
Shelf Location232d
AbstractTo examines the impact of shipping on marine biodiversity in the Mediterranean Sea, a workshop was convened in Istanbul in September 2007. One of the most important outcomes of the workshop was the preparation of four background papers outlining the legal framework and the measures available within this framework. These papers have been collected together in this volume. Chapters include an overview of opportunities under the law of the sea to improve marine environmental conservation affected by maritime traffic; a review of global experience with particularly sensitive sea areas (PSSAs); the application of international measures for the protection of the marine environment from the impacts of shipping; and maritime traffic, marine biodiversity and the Green Paper on a future Maritime Policy for the EU.
AuthorsPublishereditors: Nilufer Oral ; Francois Simard
International Union for Conservation of Nature and Natural Resources
ISBN number9782831710808
Shelf LocationDate published232d
2008
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Report on the use of PLUTOcen-F on 'Lilac' owned by Shin-Nihonkai Ferry
AuthorsH Shimizu
Date published2000
AbstractThe fuel improver PLUTOcen-F is used on a subject vessel and its performance is reported. The active compound incorporated in PLUTOcen products is the ironorganic compound ferrocene. It is reported that fuel combustion improves and soot is reduced as well as the physical structure of soot being changed to a dryer softer structure. The effect of its use is to minimise wear on piston rings and cylinder line and to reduce consumption of system oil and to keep clean the nozzle ring the blade of T-C the combustion chamber of M-E boiler and EGE.
AuthorsH Shimizu
Date published2000
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Sampling variance of species identification in fisheries-acoustic surveys based on automated procedures associating acoustic images and trawl hauls
AuthorsPierre Petitgas ; Jacques Masse ; Pierre Beillois et al.
Date published2002
AbstractIn this paper the sampling variance of species identification is developed and automated procedures are used allowing energy allocation to be carried out by a non-expert. The procedures are based on the fact that at the sampling stage trawl hauls are linked with particular acoustic images. The procedures have two steps: the classification step corresponds to species identification and the aggregation step to energy allocation. Classification is performed on the identified images. Aggregation is performed on non-identified images and results in post-stratifying the data. The estimation is then derived automatically and is conditioned by the post-stratification. Two approaches are followed one based on the echo-trace characteristics making full use of the echogram (acoustic-image classification) and the other on the spatial continuity of the species composition between trawl hauls (trawl-haul classification). These methods are described and compared.
AuthorsPierre Petitgas ; Jacques Masse ; Pierre Beillois et al.
Date published2002
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Some environmental considerations and their influence on the design and operation of ships
AuthorsJohn S Carlton
PublisherIMarE (Sydney)
AbstractFollowing a brief review of the significance of the marine contribution to air pollution on both a local and global scale the paper then considers the influence that emission controls are likely to have on ship design and operation in the future. Legislation is likely to be introduced on an international scale to limit the oxides of nitrogen and sulphur consequently these emissions are considered first in the paper. In the case of NOx emissions both primary and secondary methods are reviewed and the various implications of the direct and indirect methods of verification of compliance with emission regulations are discussed. Following this the implications of fuel sulphur levels in terms of their influence on SOx production abatement technologies and their implications for particulate emissions are considered. The paper then discusses the influence of ship design machinery selection and operational modes on emission species in general; paying attention to the CO CO2 and HC species as well as those previously considered. Finally the implications of introducing abatement technology onboard ships in terms of manning and ship operation are examined.
AuthorsDate publishedJohn S Carlton
1995
PublisherIMarE (Sydney)
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The Effect of the Wave-Current Interaction on Second Order Drift Loads
AuthorsM R Martins ; J A P Aranha ; H L Brinati et al.
Date published2000
AbstractThe aim of this work is to analyze the effect of the wave-current interaction on the second order drift loads acting on the unit. This analysis permits to estimate the influence of the wave-current interaction on the second order motion of the floating unit. One VLCC (Very Large Crude Carrier) operated by PETROBRAS in deep water is used to illustrate numerically the wave current interaction effect on the second order drift loads acting on the unit. For this analysis is used some wave and current data of the Campos basin and North Sea.
AuthorsM R Martins ; J A P Aranha ; H L Brinati et al.
Date published2000
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The Influence of Heave Motion on the Damping Force of a Mooring Line
AuthorsJ Fan ; X Chen ; X Huang
Date published1998
AbstractIn this paper we presented some investigations on the influence of heave motion on the damping of a mooring line. The variation of the dissipated energy of mooring line damping force was calculated in the time domain with the different upper end motions which were composed of a low frequency surge motion and the wave frequency heave motion. From the results we found that the wave frequency heave motion has significant effect on the damping of the mooring line on the low frequency surge motion. With the increase of amplitude and frequency of the heave motion the damping of the mooring line increases. So in estimating the damping of mooring line on the low frequency surge motion the effect of wave frequency heave motion should be taken into account.
AuthorsJ Fan ; X Chen ; X Huang
Date published1998
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The methods of analytical representation for dependencies of WIG-craft aerodynamic characteristics on parameters of its motion and the results of experimental investigation of basic configuration elements geometry influence on stability of longitudinal mo
AuthorsL D Volkov ; D A Iosafov
Date published2000
AbstractThe methods of analytical representation for dependencies of WIG-craft aerodynamic characteristics on parameters of its motion are examined. Firstly the method of determining a WIG's aerodynamic coefficients as functions of flight altitude variation rate is considered. Then the position of centre of height at large heights of a WIG-craft's flight is investigated. Finally the results of experimental investigation of basic configuration elements' geometry influence on the stability of longitudinal motion are presented.
AuthorsL D Volkov ; D A Iosafov
Date published2000
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Ultra-low emission gas turbine combustion: an experimental investigation of catalytically stabilised lean pre-mixed combustion on modern gas turbine conditions
AuthorsJeevan Jayasuriya ; Anders Ersson ; Sven G Jaras et al.
Date published2004
AbstractThe experimental study and investigations are described that have been carried out on catalytic combustion under gas turbine operating conditions. Experiments were designed to focus on the operational behaviour of single catalytic segments as well as combinations of them under different experimental conditions. Two types of fuels methane and simulated mixture of gasified biomass were considered separately for a series of catalytic combustion tests. Some of the initial results are presented. The results from this study highlight the influence of pressure space velocity air fuel ratio and air inlet-temperature on ignition combustion stability and emissions. The purpose is to gain experimental data-knowledge on the operational behaviour of different types of combustion catalysts under gas turbine operation conditions. Eventually the knowledge will be gathered together to design catalytic combustors for gas turbines running on natural gas and gasified biomass.
AuthorsJeevan Jayasuriya ; Anders Ersson ; Sven G Jaras et al.
Date published2004
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13 years on: Orimulsion operations and R and D
AuthorsP A Gunter ; C Villoria ; P Masciangioli
Date published2002
AbstractOrimulsion operations and the research and development of Orimulsion are considered. Significant resources have been committed over the past 13 years to assess the environmental risks in the event of a spill to develop a good understanding of Orimulsion spill behaviour and to develop tools in the spill response armoury. Not all of these tools are appropriate for all spills and each location should be considered on a case by case to determine the most appropriate and realistic response plan. Studies have also been undertaken on the detection and monitoring of spills and on assessing shoreline impacts and clean up strategies should spilled Orimulsion reach the shore. Parallel work is currently on- going in France and Canada evaluating the natural persistence and recovery of contaminated shorelines and determining optimum hydraulic washing conditions for removal of bitumen.
AuthorsP A Gunter ; C Villoria ; P Masciangioli
Date published2002
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A 2-D stochastic model for the hydrodynamic dispersion of pollutants on the sea surface
AuthorsM Di Natale
Date published1995
AbstractA 2D random walk model for the analysis of the hydrodynamic dispersion of pollutants on the sea surface is presented. In this mathematical model coastal circulation is produced by the action of the wind on the sea surface. The equation of advective-diffusive transport is based on the hypotheses of Taylor's theory and the solute is assumed to be non- reactive. The advective component of the transport is due only to wind-generated circulation. A numerical example has been reported based on suitable computer programs implemented for the analysis of the field of motion and dispersion phenomenon. A numerical application of the proposed method is presented to simulate space-time evolution of a polluting surface plume in the Pozzuoli Gulf located in the Tyrrhenian Sea.
AuthorsM Di Natale
Date published1995
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A Nonlinear Model for Random Forces on a Vertical Cylinder Set in Finite Depth Water
AuthorsL R Lando ; R Gentile ; G Scarsi
Date published1998
AbstractTwo simplified models with a different level of accuracy are suggested which are capable of providing to third order of approximation the drag inertia and total random forces acting in the flow separation regime on an isolated smooth vertical cylinder. The model adopts the TMAR model to identify the surface frequency spectrum on decreasing depths the corresponding spectrum on deep water being assigned. It uses the Morison equation to obtain the sectional random forces from which the total ones are deduced in analytical form; specifies the equation by using the kinematics to third order of approximation and introduces a polynomial development to evaluate the drag forces. Some considerations are made on the behaviour relevant to several significant statistical quantities pointing out the differences with regard to a complete model and some comparisons are made with experimental data from other authors.
AuthorsL R Lando ; R Gentile ; G Scarsi
Date published1998
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A study on fatigue management system for LNG carriers using fatigue damage sensor
AuthorsToshiro Koiwan ; Norio Yamamoto ; Hirotsuga Dobashi et al.
Date published2006
AbstractA pro-active safety management system of ship structures which quantifies the aging effect such as fatigue and corrosion on ship structural integrity is proposed as a new approach to ship's structural surveys that have conventionally been done according to a more passive management system. A compact fatigue damage sensor has been developed that can detect accumulated fatigue damage in the weld structures by being stuck to the member and then inspected after a certain period. This sensor has been applied to hull structures of an LNG carrier for experimental purposes and its long-term durability under the severe environments of the ship is ascertained and quantitative data on accumulated fatigue damage from this ship are obtained. HFMS (hull fatigue management system) is proposed that uses this sensor and is part of HAMS (the hull aging management system). A study on the improvement of accumulated fatigue damage detection accuracy using this sensor is introduced. The evaluation method was applied on a trial basis to an LNG carrier and results were successfully obtained.
AuthorsToshiro Koiwan ; Norio Yamamoto ; Hirotsuga Dobashi et al.
Date published2006
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An experimental study of the ecological impacts of hydraulic bivalve dredging on maerl
AuthorsC Hauton ; J M Hall-Spencer ; P G Moore
Date published2002
AbstractA short-term experiment to assess the ecological impact of a hydraulic blade dredge on a maerl community was carried out during November 2001 in the Clyde Sea area on the west coast of Scotland. A fluorescent sediment tracer was used to label dead maerl which was then spread out on the surface of sediment to act as a proxy for living maerl. The likely ecological consequences of hydraulic dredging on maerl grounds are discussed and a case is made for protecting all maerl grounds from hydraulic dredging and establishing them as reservoirs to allow for the recruitment of commercial bivalve populations at adjacent fished sites.
AuthorsC Hauton ; J M Hall-Spencer ; P G Moore
Date published2002
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Characterization of Environmental Loads on Subsiding Offshore Platforms
AuthorsS Pawsey ; D Driver ; J Gebara et al.
Date published1998
AbstractWave loads were computed on three North Sea jackets which have been exposed to an increasing level of mudline subsidence. In order to estimate wave loads on the jackets and decks new environmental criteria were established from data not available at design. Due to the increased risk of waves impinging on the decks wave forces from both the jacket and the decks were computed and used in a reliability analysis. The wave forces on the decks were computed from a procedure that estimates the various components of the wave forces using a strong theoretical background incorporating the effects of shielding and blockage. The wave in deck procedure was indirectly calibrated and subsequently verified against model tests. The new procedure eliminates the need for developing the wave in deck loads in a separate software and incorporating them as nodal loads and allows the maximum load to be calculated accurately eliminating the effect of the phase angle difference between the jacket load and the deck loads.
AuthorsS Pawsey ; D Driver ; J Gebara et al.
Date published1998
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Experiment on the bottom shear stress of sand ripple bed under wave action
AuthorsShi Sen Li ; Jie Gao ; Chongren Qin et al.
Date published2005
AbstractWhen the strength of wave travelling over a sandy bed reaches a certain condition the bed form is changed to become a sand ripple bed. The formation mechanism of the bottom shear stress on the ripple bed differs from that on a plane bed. However investigation into the bottom shear stress on a ripple bed is the foundation of an investigation into wave damping with travelling and sediment transport. Therefore this investigation is significant. Bottom shear stress was measured directly and provided formulas to calculate the bottom friction factor and shear stress on the ripple bed. The expression is very simple and suitable for engineering practice.
AuthorsShi Sen Li ; Jie Gao ; Chongren Qin et al.
Date published2005
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Feasibility of ballast water exchange methods on the open sea
AuthorsMarko Perkovic ; Matej David
Date published2001
AbstractThe introduction of nuisance species (bio-pollution) represents a threat to human health and losses for the national economy. Research into prevention methods has lead to the statement that organisms which live in the open sea and are released in coastal waters (and vice versa) generally do not survive. On this basis the IMO recommends (in two methods) the sequential or the flow-through method of ballast water exchange on the open sea. Here it is questioned whether these two methods are safe. The feasibility of these two methods is verified. Research is carried out on the computer simulator Cargo Handling Trainer 2000b Norcontrol on the ship model VLCC (very large crude carrier) 220.000 DWT. The results of the research are presented together with guidance for security improvements.
AuthorsMarko Perkovic ; Matej David
Date published2001
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Influence of freezing on the dynamic properties of a silty sand
AuthorsYao-Chung Chen ; Chao-Chong Huang
Date published2002
AbstractThe 1999 Chi-Chi earthquake in Taiwan caused widespread liquefaction in inland alluvial areas and in several coastal hydraulic fills that led to significant damage to lifeline systems buildings and harbour facilities. As a result a 3-year integrated research programme was set up to perform an overall evaluation on the liquefaction behaviour of granular materials in Taiwan and to make necessary modifications to the current practice of assessing the potential of sand liquefaction. The influence of the freezing process on the dynamic properties of a silty sand is discussed. The specimens were recovered from a liquefied site during the Chi-Chi earthquake. Remoulded samples were prepared by moist tamping method with two different water contents 5% and 28%. Samples were applied a freeze-thaw process before being subjected to undrained cyclic triaxial tests. The effects of freeze-thaw process on the liquefaction resistance were investigated together with other factors such as relative density and fines content. Resonant column tests were also carried out to study the effects of the freeze-thaw process on the maximum shear modulus.
AuthorsYao-Chung Chen ; Chao-Chong Huang
Date published2002
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Marine Accident Investigation Branch (MAIB) Report of the Chief Inspector of Marine Accidents into the reopened inquiry into the explosion on the motor tanker Esso Mersey on 4 September 1991 resulting in the loss of two lives
AuthorsMAIB
PublisherDepartment of Transport (DOT)
AbstractFollowing new evidence that the contractor who carried out work on the cargo pump of the Esso Mersey failed to exercise acceptable quality control procedures the inquiry was reopened. The inquiry determined that quality control procedures were inadequate but the contractor was not alone in this respect.
AuthorsDate publishedMAIB
1996
PublisherDepartment of Transport (DOT)