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Time-reversal techniques have been demonstrated in ultrasonics and underwater acoustics environments. A technique resulting from the analysis of the iterative time reversal process has been developed. This is called the DORT method (decomposition of the time reversal operator) is a scattering analysis technique using a source receiver array (SRA). The efficacy of this method for ultrasonic detection and selective focusing on different scatterers in an inhomogeneous media has been shown. Mordant et al have shown the robustness of the method in an ultrasonic waveguide. While the performance of classical detection methods usually decreases due to multiple reflections at the waveguide interfaces the DORT method takes advantage of the waveguide boundaries and multi-path propagation in order to improve spatial resolution. The first experiment in a realistic shallow water waveguide is presented. The experiment uses a 24-element source receiver array at 12 kHz central frequency. The DORT method is applied to detect two targets at 27 m distance. Numerical and experimental back-propagation of the dominant singular vectors of the array response matrix enable the localisation of the individual targets. After a brief description of the experimental set-up the measurement of the array response matrix K(ù ) is explained and the singular value distribution is shown revealing the apparent reflectivity of each scatterer.

Public awareness and understanding of ocean issues is key to generating the political will to address these problems. The case for the importance of an ocean literate public in moving from issues to solutions has been made in a series of reports by national commissions starting with the Stratton Commission in 1969. Since 2004 there has been a renewed interest in promoting ocean literacy both at the K-12 grade levels and of the general public. Aquariums and other informal science institutions are seen as key players. The Aquarium of the Pacific has focused on public ocean literacy and during its 10th anniversary year has embarked upon a major initiative to bring major ocean issues to the public in new and novel ways to evaluate the efficacy of these modalities and through a national conference in May 2009 to bring scientific experts together with experts in exhibit design film-making environmental journalism and story0twling to develop a portfolio of materials designed for different modalities of delivery for each of the major ocean issues that can be used widely to engage educate and enpower the public in moving from ocean issues to solutions. Participation by the MTS and its members is invited. In this paper the need for an ocean literate public is briefly explored together with what ocean literacy means the special roles that free-choice learning (informal science) institutions can play. The Aquarium's 10th Anniversary program is then described as well as its national conference in an attempt to elicit collaborators from MTS.

A full-scale field trial of a taut leg mooring was performed by Saga Petroleum in 1996 offshore Norway. The trial used suction anchors and two types of fibre ropes attached to a semi-submersible drilling unit. The aim was to qualify the technique as an effective mooring system for floating drilling units. The execution of the trial is described in detail. Fibre rope data obtained from other laboratory and field measurements are discussed and it is concluded that sufficient data are available to qualify these ropes for taut leg mooring. The benefits of taut leg moorings are presented in terms of their use on a congested seafloor in shallow water (200-400 m) and in terms of deep water (800-1500m). The trial successfully demonstrated effective installation and retrieval of suction anchors and fibre ropes from a standard AHTS vessel. It is concluded that this method of taut leg mooring is a viable alternative to conventional mooring and dynamically positioned units.

Recent developments in CFD (computational fluid dynamics) associated with increasing power of computer are able to offer further opportunities to realize CFD-based aerodynamic or hydrodynamic design optimisation. However the increasing complexity of engineering systems together with the inherent difficulty to deal simultaneously with a growing number of design goals and constraints has raised interest in the development of efficient global optimisation schemes which can be used with computationally expensive analysis tools such as RANS (Reynolds-averaged Navier-Stokes) solver. The main focus of the present work is on investigation and development of such optimisation schemes and demonstration for practical design problem. High-performance multi-objective evolutionary algorithms for CFD (computational fluid dynamics)-based design optimization are presented. In particular Binary Coded MOGA (Multi-Objective Genetic Algorithm) and RC-MOGA (Real Coded MOGA) are investigated. In order to overcome the limitations of classical approach for particular issues in CFD-based multi-objective design optimisation advantages of evolutionary algorithms are discussed in conjunction with parallel nature of the algorithm along with inherent efficiency of parallel processing. Message Passing Interface based parallel coding methods are also discussed so that capability of distributed-memory-model parallel computing environment is fu91918

Petrobras is developing new fields in Campos Basin offshore Rio de Janeiro - the main oil province in Brazil responsible for 85% of national production. The Petrobras HP-HT pipeline P-53/PRA will be installed at Marlim Leste field in Campos Basin. A numerical study for this pipeline is presented. It will connect P-53 platform in deep-water (1031m) to an Autonomous Platform for Intermediate Pumping (PRA-1) in shallow water (100 m). HP-HT pipelines resting on seabed can develop thermal buckling which is an important concern for the pipeline structural integrity. The aim of this study is to verify the P-53/PRA-1 pipeline behaviour during lateral buckling due to thermal cycles and pressure variations using a new approach for the pipe-soil interaction model in contrast with the traditional Mohr-Coulomb friction model. The pipe-soil interaction model considers soil berms formed due to pipe cyclic displacements representing different phases of the soil lateral reaction force versus displacement curve: breakout force suction release berm formation and residual resistance. The results presented compare the traditional Mohr-Coulomb model with the proposed one for several loads cycles analysing displacements stresses and strains behaviour during thermal buckling.

Conf held in Aberdeen 26 - 27 March 1985 Papers are Hook up and commissioning technology - the North Sea effect Historical lessons for future design and hook ups Hook up - where does it start? Hook up experience on statpipe development project platforms How to optimise an offshore hook up Approaching hook up and commissioning through management of risk Cost savings in hook up using big lifts The completion strategy for offshore hook up projects - the construction engineers role Cost planning integration during offshore hook up and commissioning Hook up minimisation programmes - recent experience from the Norwegian sector Site based materials management systems - a cornerstone of succesful hook up control Communications - the forgotten link in hook up and commissioning Gravity platforms and their hook up Some ways to reduce the cost of offshore hook up Buchan Alpha - offshore platform inshore refit Offshore logistics - an overview Supply bases - the future - an operators view A practical solution to cost control and analysis of logistics in the offshore environment using computer technologies Personnel The logistics of materials and documentation for an offshore development The future of the offshore vessel market The development of helicopter support to the offshore industry The role of the all cargo airline as a support to the oil and gas industry

Human factors practitioners working as part of a ship design programme face a set of problems on a scale to those involved with smaller stand-alone equipment. They have to address a wide range of often competing human factors issues across a ship. Usually the individual systems comprise off-the-shelf components whose design is outside the scope of the ship's programme. Components will be chosen and the systems designed by large teams of architects engineers and draftsmen with various degrees of appreciation of the human factors issues. Invariably professional human factors resources will be thinly spread and human factors practitioners will have to make hard choices about where to concentrate their efforts. This paper summarises practical techniques for maximising human factors influence derived from experience in real-life projects. It shows how techniques such as task analysis can be used to identify critical human factors risk areas and thus focus design effort. It explains how human factors practitioners can become properly integrated within ship design teams and can influence the design by educating assisting and monitoring the various technical specialisms. In particular it describes how human factors practitioners can contribute to design review and can sign-off procedures by managing the traceability of design back to critical operational and safety requirements. Also considered is how to carve the warship design problem into manageable portions and thus achieve effective human factors integration.

The extraction of hydrocarbons has recently moved to deeper water depths (in excess of 1000 m). The deepwater deployment of production systems has been associated with certain critical issues for example VIV (vortex induced vibration) of risers. VIV remains a largely unsolved problem. The recent requirement for deployment of marine risers in deep-water has provided an additional thrust to the VIV research. The effort to mitigate this problem has led to a number of solutions for VIV suppression. One of these solutions is to add a vortex suppression device such as helical strakes perforated shrouds fairings splitters guiding vanes spoiler plates etc. Helical strakes have been used for long time in civil structures such as chimneys funnels and tall towers as a means of suppressing wind-induced vibration and are now being widely used as a means of VIV suppression for marine risers. Hydrodynamic coefficients of cylinders fitted with strakes in oscillatory flows are investigated. Three different pitch ratios are tested - the pitch ratios of infinity 8 and 4. The cylinders are forced to oscillate in otherwise calm water in a water tank. To validate as well as to compare the experiment results a smooth cylinder is included in the test matrix. Digital signal filtering is found to influence the results obtained. Thus sine-fitted signals are used to obtain the coefficients. For cylinders with strakes it is also found that the coefficients vary little with Reynolds number. It is further concluded that the pitch ratio has a significant impact on the hydrodynamic coefficients.

Nelly Bay Harbour on Magnetic Island Queensland is located in both the GBR (Great Barrier Reef) Marine Park and in the GBR World Heritage Area. It is composed of breakwaters marina ferry terminal residential development and commercial enterprises and has had a very long and controversial history. Started in the late 1980s the original proponent abandoned construction in the face of pressure from environmental groups and some difficult engineering problems. Recently the state government resurrected the project with additional funding. The proposed construction process requires dewatering during construction and dredging of the marina basin. This dewatering will be a continuous process since the breakwaters and substrate of the marina cannot be completely sealed. The effluent has the potential to damage coral reefs that lie along both sides of the marina as well as along much of the nearby island coastline. It was proposed that the extracted water be discharged approximately 100 m seaward from the HWM (high water mark). It is investigated whether an outfall situated 400 m from the HWM would reduce the concentration of sediment over coral colonies. Methodology is presented followed by simulation details and results.

The primary aim of this research is to locate the source of the vortex-induced vibrations (VIV) for long flexible cylinders at high-mode number and to help determine the source region for future predictions. The two Gulf Stream tests were conducted to collect data on a scale-model pipe that was excited at high-mode numbers. Two methodologies are presented to locate the area of the region that is the source of the vibration. In VIV the current causing the vibrations is important. Therefore one important question is which section of the pipe will be the source of the vibrations for a known current profile. This source region is known as the power-in region. Four different factors are presented that effect the locations of the power-in region: the angle of the pipe with respect to the vertical the gradient of the current direction the current profile and the end effects at high mode number. A dimensionless parameter is presented which helps in the prediction of VIV given a current profile. The power-in factor predicts the region where the source of the vibration occurs using a combination of the current velocity and the source region length.

Hydrocarbons have recently been discovered in the shallow waters of the Northern Caspian Sea. There is now a need for intensive drilling to be carried out shortly to explore this potential. Until now the only experience of operating mobile drilling units in seasonally ice-infested waters has been in on the Sunkar drilling barge at Kashagan and Kalamkas. However with increased drilling activity imminent innovative drilling concepts are required to maintain drilling operations during the ice period with conventional non-ice-resistant drilling platforms. External SIBs (shoulder ice barriers) are proposed to protect conventional jack-up drilling rigs from the hazards of drifting ice in shallow water. The design of SIBs design should increase ice rubble generation at the ice-facing slope and thereby provide sufficient protection from drifting ice impact. The modular concept of the SIB makes it possible to deploy each module in a floating mode to site where they are ballasted and connected to each other forming a sheltered position for the jack-up. Just before the end of the drilling campaign the SIB modules may be retrieved by de-ballasting and towing out without significantly impacting the environment.

Naval operations can be seriously disrupted by the presence of sea mines in operating areas. Tow innovative conceptual designs for mine countermeasures ships are offered together with an operational concept for their timely and efficient employment in conducting mine warfare. The first design concept is for a small SWATH (small water plane area twin hull) vessel for mine hunting in near shore waters. These small craft (Drones) are crewless and remotely controlled from a mother ship (Host). They are also stealthy to enhance clandestine operations in the hostile littoral prior to arrival of an expeditionary assault force. The Host vessel solves the problem of transporting small craft to remote locations and supporting mine countermeasure operations with minimal dependence on deployed naval combatants. The Host has space and services for maintaining several Drones as well as unique capabilities for launch and retrieval in rough seas. Cruise speed of the Host is adequate to accompany an amphibious task force in all sea states. Endurance is sufficient to reach most remote locations via ports of call. These new SWATH designs and the HAD (Host and Drone) concept of employing them with amphibious forces in advance of assault are considered to be fundamental to the success of future marine expeditionary campaigns.

The architecture of an inspection AUV (autonomous underwater vehicle) is much more complex than that of a survey type AUV since it requires high manoeuvrability and hovering capacity. It needs a specific AMS (autonomy management system) and navigation software as well as dedicated sensors to allow it to navigate relative to the structure to be inspected instead of the type of 'absolute' navigation usually used for survey AUVs where the only purpose is to give an accurate location of the vehicle. The relationship between different autonomy-related issues due to this complexity is shown using the findings from the development and testing of the ALISTAR 3000 AUV. This AUV is designed to answer the complex requirements to enable the inspection of underwater structures such as pipes wellheads mooring lines through embarked intelligence. The focus is on the functional description of the AMS in displaying different dual concepts that help to structure general functions linked to autonomy: supervisor and vehicle perception and decision symbolical and numerical descriptions mission and environment description external and internal worlds etc. This dualist approach leads to an AMS whose structure comprises one main supervisor

Stirred tanks have wide applications in the chemical and process industries. Crystallisation operations liquid-liquid extractions biological fermentations and heterogeneous catalytic reactions are just a few examples of industrial operations usually carried out in mixing tanks. Traditionally solid-liquid mixing has always been regarded as an empirical technology with many aspects of mixing dispersing and contacting where related to power draw. One important application of solid-liquid mixing is the preparation of brine from sodium formate. This material has been widely used as a drilling and completion fluid in challenging environments such as in the Barents Sea. Large-eddy simulations of a turbulent flow in a solid-liquid baffled cylindrical mixing vessel with a large number of solid particles are carried out to obtain insight into the fundamental aspects of a mixing tank. The impeller-induced flow at the blade tip radius is modelled using the dynamic-mesh Lagrangian method. The simulations are four-way coupled which implies that both solid-liquid and solid-solid interactions are taken into account. By using a soft particle approach the normal and tangential forces are calculated acting on a particle due to viscoelastic contacts with other neighbouring particles. The results show that the granulated form of sodium formate may provide a mixture that allows faster and easier preparation of formate brine in a mixing tank. In addition it is found that exceeding a critical size for grains phenomena such as caking can be prevented. The numerical results obtained suggest that

During offshore drilling operations marine risers carry mud and debris from below the sea floor and during production operations they are responsible for transporting oil or gas from the hydrocarbon reservoir to the surface platform. The integrity of a marine riser is therefore critical to the success of offshore drilling and production. The flow of seawater around marine risers is subject to vortex shedding which excites oscillations known as VIV (vortex-induced vibrations). When the VIV frequency approaches one of the natural frequencies of the structure resonance or lock-in occurs. This results in enhancement of the vibration amplitude of the structure and may have potentially destructive consequences due to high bending stresses and fatigue damage of the riser. At present the production of this phenomenon is one of the most challenging areas in the offshore industry. In experimental investigations of VIV large-aspect ratio risers - that is long cylinders with relatively small diameters pose a modelling challenge. This paper focuses on the development field-testing and data analysis of a large-scale model riser capable of transmitting data in real-time under realistic operating conditions. The large-scale riser was mounted to the port side of a small vessel and towed off the east coast of Newfoundland through a series of vessel velocities corresponding to realistic operating conditions for deep-water risers. Results are presented. Also included is an analysis of the modal vibrations experienced by the riser as well as the in-line and cross-stream motions over a series of vessel speX35409

Diesel TES Engine Oil has a high-energy efficiency and can therefore help to reduce carbon dioxide emissions and so it is expected that this will be widely adopted. However several issues remain including the bother of engine oil maintenance. The purpose of this research was therefore to lengthen the maintenance interval of the engine oil to 16000 hours. To achieve this longer maintenance interval a special oil was developed that has a synthetic base stock. Simulations of the oil's degradation were carried out and it was succeeded in preventing degradation by developing a system for extracting degraded oil and adding new oil. It was also made possible to monitor degradation of engine oil by installing a soot sensor to measure the concentration of soot which is the factor that has the largest effect on the degradation of diesel engine oil. In addition an electrostatic dust collector was installed to avoid problems caused by soot contamination. This collector worked well when the oil deteriorated. The verification tests of this system showed that the oil's properties stopped changing completely after 1500 hours of operation and operation is now continuing smoothly at the 8000-hour point. However even if the oil maintains its high performance tests of small engines have confirmed that the conditions of the pistons change over time. While engine oil maintenance can be avoided the engine itself must continue to be maintained at regular intervals.

Daring the Royal Navy's new Type 45 Destroyer first went to sea in July 2007 and is due to enter service in February 2010. She uses an HV (high voltage) (4.16 kV) IEP (integrated electric propulsion) system with LV (440 V) supplies derived directly from the HV bus bar via transformers. The LV distribution system is therefore subject to the transients seen on the propulsion bus bar. This paper looks at the methods used to capture and analyse quality of power supplies data onboard. The results show that the requirement for Def Stan 61-5 - Stanag 1008 supplies is met although the envelope of allowable excursions is fully explored. The expertise built up over a number of sea trials has enabled problems to be rapidly identified and resolved. The causes of some unusual and unexpected excursions are explored. The response of the system to LV short circuit faults was also captured and is reported in this paper. As might be expected a number of equipments have failed during setting to work with assertions that QPS (quality of power supply) excursions are the root cause. A sample of the resultant studies is presented to illustrate the value of the QPS capture methods used in resolving issues speedily and economically. From the experience of Type 45 design and operation proposals are made to reduce the cost of procurement through management of QPS requirements.

The Joint Wildlife Countryside and Environment Links (Joint Links) believe that the UK urgently needs a strategic plan-led approach in the marine environment to help avoid or reduce conflict to identify and permit appropriate and compatible developments and to protect and enhance important environmental and social assets from inappropriate development. Marine spatial planning is fundamental to deliver the Government's vision as detailed in the Marine Stewardship Report. The merits of such an approach are identified and it is explored how such a system might operate in practice. This follows a number of government commitments and initiatives. As development and activity increases in the marine environment the sectoral approach is no longer an option. It is thought that a plan-led system is now essential. This plan-led system is presented. It is believed that a strategic marine spatial planning based on natural ecosystem boundaries is essential to begin to halt the decline in marine biodiversity to protect underwater cultural heritage and to promote and plan for sustainable development and use in the marine environment. It is considered why the UK needs a strategic marine planning system. This is followed by consideration of policy what a marine spatial plan (or strategy) might look like and who would develop such a plan. The core principles aims and objectives are outlined. The Joint Links are therefore calling upon the Government to promote and develop a system of strategic Marine Spatial Planning as a product of the current DfT review.

A 3D numerical model ASL-COCIRM is applied to examine the impact of the Burrard Generating Station cooling water on the circulation patterns and thermal regime in the receiving water of Port Moody Arm. A key aspect involves properly incorporating the submerged cooling water buoyant jet into the 3D model. To overcome the scale and interface barriers between the near-field and far-field zones of the buoyant jet a sub-grid scheme is applied and the coupled system of equations of motion heat conservation and state are solved with a single modelling procedure over the complete field. Special care is taken with the diffusion and jet entrainment by using a second order turbulence closure model for vertical diffusion and the Smagorinsky formula for horizontal diffusion as well as jet entrainment. The model is calibrated and validated in terms of buoyant jet trajectory centreline dilution and temperature and velocity profiles. Extensive modelling experiments with and without the Burrard Generating Station in operation are carried out to investigate the receiving water circulations and thermal processes under the influence of the cooling water discharge. The model results reveal that under the influence of the cooling water discharge peak ebb currents are stronger than peak flood currents in the near-surface layer and the reverse is true in the near-bottom layer. Meanwhile the model reveals a well-developed eddy at the southeast side of the buoyant jet in the near-surface layer. It is also found that the warmer water released from the cooling water discharge is mainly confined to the upper layer of the Arm whX38886

Tides and large-scale disturbances to the ocean waters during cyclone storm surge and tsunamis could be classified under long waves governed by SWE (shallow water equations). Appropriate modelling of such shallow water processes for real ocean have to be carried out numerically since the ocean has irregular boundaries and the equations under consideration are non-linear. As the scale of disasters due to such phenomena is massive the modelling gains centre stage for the purpose of forecasting the level of the disasters and the mitigation measures. The SWE being compact and simpler is an effective mathematical tool in the modeling of tsunamis on the global earth. This can also model tsunami travel times and landfall amplitudes close to the observed data. However the irregular boundaries of the coastlines of the global ocean can better be represented using unstructured grid and more accurate solution can be achieved than the structured grid. SWE are solved using an UEFEM (unstructured explicit finite element method) to simulate long waves in the ocean. The formulation of the UEFEM has been described and found to be computationally efficient for large problems such as basin level modeling of tsunamis. Different domains have been considered to simulate the propagation of the waves due to an artificially imposed initial disturbance. The domain of Bay of Bengal has been considered for simulation with an initial disturbance which resembles the type and location of the 2004 Indian Ocean Tsunami. The Wave elevation and deformations as well as time of travel of tsunami are reproduced. The method hence has high potential of being attractive forX37823 Modelling of the sediment transport at the Belgian coast