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Advances in knowledge of the oceans are limited by a lack of sustained observations over extended periods and large areas. More than 20 years of planning has resulted in current efforts to build support for an integrated ocean and coastal observing system. Numerous user groups will benefit from this. Different user groups will have different motivations and requirements for ocean information. An observing system will need to obtain an extremely wide range of information covering the entire spectrum of ocean disciplines. The issue now is how to translate growing consensus on the need for an integrated ocean and coastal observing system into support and understanding by Congress and the federal government the oceanographic community and public that is necessary to make it a reality. Over the past 20 years we have seen successful planning and implementation of a number of large federal inter-agency efforts to support environmental research monitoring and prediction. Three in particular (weather service modernisation global change research and the converged polar-orbiting meteorological satellite program) offer case studies for identifying common elements of a successful program that can be applied to the ocean and coastal observing system. These are presented followed by implications for an ocean and coastal observing system.

Offshore pipelines are often placed in the seabed by 'jetting' the soil to soften it and allow pipeline penetration. This is shown to have implications for the resistance of the soil to upwards pipeline movements caused by pipeline temperature changes (upheaval buckling). To investigate this a series of centrifuge model tests have been carried out to investigate the uplift capacity and the load-displacement behaviour of pipelines buried in recently liquefied clay. Both short and long-term loadings are considered. The undrained uplift capacities were seen to be lower than the drained capacity so that it was the undrained failure conditions that were critical. Recently liquefied clay may still be consolidating when pipelines are commissioned and are subject to upheaval loads. In such cases the effective stresses in the soil (and thus the shear strengths) at the expected switch-on time have to be calculated in order to calculate the uplift capacity of the pipeline. A simple method is presented which predicts uplift capacity from the average degree of consolidation of the backfill. Good comparison between the experimental results and the simple prediction method suggests that such a method may be appropriate for initial pipeline design.

Infrafone invented a method for cleaning boilers by infrasound in the 1970s. The first sonic cleaner operating at infrasound frequencies was installed in 1978 on a paper mill boiler. Since then there have been some 500 successful installations. However at the beginning of the current project in the early 1980s there were also many installations where there was no cleaning effect at all by the infrasound. It was understood that there is a certain combination of the parameters of a sound field that has a cleaning effect. It was also understood that that combination was achieved by luck in some installations but not in others. Some questions are presented and answered about: which parameter of the sound field has a cleaning effect; how often and at which cycle time should the sonic cleaner operate; what should the frequency of the infrasound be; where should the sonic cleaner be installed. It is concluded that successful cleaning of exhaust gas boilers using infrasound requires high-particle velocity of the sound at the heating tubes. This is best induced by generating sound intermittently at a frequency equal to a harmonic of the natural frequency of the gas column in the uptake using a device located upstream or downstream of the boiler in a vicinity of high acoustic resistance.

The book is a report on 'The World Coal Study' (WOCOL), which was an international project of 18 months duration, involving over 80 people from 16 major coal-using and coal producing countries. The report presents a plausible solution for the world's most acute energy need - increasing fuel supplies to support essential growth. It shows how coal can meet that need and be mined, moved and used in ways which meet stringent environmental standards. The major conclusions of the project include that: coal is capable of supplying a high proportion of future energy needs, that coal can be mined, moved and used in most areas in ways that conform to high standards of health, safety and environmental protection by the application of available technology and without unacceptable cost increases and that the technology for mining, moving and using coal is well-established and steadily improving. Subject areas included within the sections/chapters are: The need for coal; World energy prospects; Coal markets and prices; Environment, health and safety; Coal resources, reserves and production; Maritime transportation and ports; Coal-using technologies and Capital investment in coal.

Extensive tank test programmes continue to be used in the offshore oil and gas industry (i.e. a physical modelling technique as distinct from the numerical modelling that is also used in the design of offshore structures.) Technip who specialise in float-over installation methodology has developed a new solution allowing topsides installation onto either floating platforms or conventional jackets at low or high air gap. The DSIV is a catamaran-shaped vessel capable of installing or uninstalling up to 20000T topsides on a jacket or spar at a 20 m final airgap. In order to validate the development of a new catamaran vessel for deck installation by the float-over method an integrated set of tank testing and numerical analysis has been carried out to explore the degree of confidence to which tank test experiments can provide benchmark datasets for the numerical model using the hydro-structure coupling method. Firstly an overview of the challenges with hydrodynamic verification of a novel vessel design is given. The role of the model testing in the verification process as well as the range of relevant values to be measured is then discussed. In particular the combination of model test and computer simulation for validation of the coupling approach is presented. Initial considerations such as the mathematical methodology coupling) for the investigation of the catamaran phenomenon

Around 75% of the Earth is covered by water but only about 0.1% of the oceans' bottoms have been explored. This research has shown that there are large quantities of precious metals and minerals and methane hydrates to be found there. Currently a large submarine can only dive to a depth of about 400 m (1312 ft) but the deepest part of the ocean is 29 times deeper than this. As a submarine dives deeper and deeper the external hydrostatic pressure increases so that the wall thickness of the submarine has to be increased. Eventually the wall thickness becomes so large that the vessel has no reserve buoyancy and will sink like a stone. The only way to overcome this problem is to use a material with a higher strength to weight ratio than high-strength metals. Such materials are GFRP (glass fibre reinforced plastic) and CFRP (carbon fibre reinforced plastic). There are many other composites that are suitable but GFRP and CFRP are cheaper than many of the other composites and have been used successfully for other structure. This paper describes the investigation experimentally and theoretically into the collapse of 22 composite tubes each of circular cross section under the application of external hydrostatic pressure. Investigations centre on the collapse of fibre reinforced plastic tube specimens

Numerical simulations of a foil in heaving or in pitching motions near a flat ground are presented. Four flow configurations are considered and calculated. The unsteady incompressible 2-D N-S equations are solved with a simple version of the Smagorinsky turbulence model in all computations. A multi-block multi-group grid system is developed for numerical implementation of complex geometry conditions and for simulation of foil motion. Some aerodynamic characteristics are studies versus the Strouhal number. Several static pressure contour plots are used to show the influence of ground clearance. The Reynolds number studies is 1x10 to the power 6. Some parameters varied to investigate their influence upon the foil: ground clearance the amplitude of heaving or pitching oscillation and the Strouhal number. Results are presented and discussed. The computational results show that it is possible to find an optimum value of the Strouhal number for the design of propulsion efficiency of a foil in unsteady motion near a flat ground. It is also shown that the ground effect can improve the efficiency of propulsion. Graphs are presented on pages 300-302.

While all the major NATO navies have been under considerable pressure to downsize following the end of the post-Cold War the higher degree of political instability worldwide has led to a desire to increase the deployability of the reduced number of naval assets. Thus there has been an increased interest in providing a new generation of naval support vessels as part of each navy's contribution of Coalition peacekeeping. These new support ships are often also required to provide a contribution of amphibious capabilities including humanitarian tasks in littoral operations. This means there is a challenging combination of capabilities being sought from the current replacements of traditional afloat support ships. The design work undertaken by the Design Research Centre at UCL is described. This work consists of designing a range of possible design options to investigate the impact of capabilities on the configuration of this innovative concept exploring the requirement's two levels of capability namely 'shall' and 'should' as part of designing to cost and capability. A range of concepts was designed using the USL Design Building Block approach using the SURFCON module of the Graphics Research Corporation PARAMARINE ship design system. The advantage this approach gave in designing these novel solutions is shown through the ability of the DRB concept approach to balance both technical and configurational features thereby enabling significantly different ship styles to be readily produced and compared.

Crude oil tankers play a strategic role in the transportation of crude oil all over the world. The risk of oil tanker accidents is particularly high and this has been recognised as a result of many accidents with enormous oil spillage mass into the sea in the last decades. These oil spillage disasters have endangered the natural life and caused an economical loss due to the loss of crude oil ship damage or ship out of service time and due to the expenses necessary to deal with oil pollution. Corrosion can be defined as the chemical or the electrochemical reaction between a material usually a metal and its environment that produces a deterioration of the material and its properties. Marine structures in contact with seawater are very prone to corrosion in addition to the contact with their cargo which is often also a source of corrosion. The corrosion deterioration of crude oil single hull tankers is considered taking into account the corrosion degradation process from both the internal and external sides of plating. The corrosion degradation of the external side of the tanks is modelled as corrosion degradation under atmospheric conditions or under immersion conditions or under repetitive atmospheric and immersion conditions depending on the location of the plate elements. The corrosion degradation of the internal side of the crude oil tank is estimated as corrosion under tank environment considering the chemical and physical conditions of the crude oil. The different corrosion deterioration mechanisms under the different environments and the correspondiX13028 Corrosion monitoring in the oil petrochemical and process industries

This paper critically assesses the requirement of the time-domain diffraction and motion analysis program for use in the design of a semi-submersible. The time-domain motion behavior results are compared with physical wave-tank measurements. A Noble deep-water semi-submersible drilling vessel is considered for this assessment. In the time domain approach a numerical wave tank and its free surface are modeled in the computer. A nonlinear regular wave is generated on the free surface with a potential flow fluid media. The panel body is evaluated for its panel pressure and the rigid body floating motion in the time-domain. The effect of instantaneous position of the vessel with respect to the wave and the integration of the forces to the actual wetted surface above and below the mean-free-surface is considered. The wave incident diffraction radiation pressures and the rigid body motions are obtained for large regular waves.

This book deals with data structures, the science and art of arranging data in computer programs. It is intended for an audience of professional engineers and students interested in creating engineering software, so it concentrates on the kinds of data structures most useful in engineering applications. These include not only all important vector and arrays of numerical computation, but also the stacks, queues, and linked structures of communications engineering, for they all serve as building blocks in creating the complex data entities encountered in software practice. While the illustrative examples in this book are drawn mainly from electrical engineering, its subject matter is applicable over a much wider spectrum of applications. Substantially the same data management problems arise in software for structural, transportation, and various other engineering branches. Engineering software typically involves extensive numerical computation so engineers are often very well trained in numerical methods and scientific computation techniques. Yet many come to recognise the close interplay of computational method and data structure only after entering into professional practice or advance study. As the programming languages used in engineering software grow to encompass object-oriented programming-particularly since the introduction of C++ and Ada – the right choice of data structures becomes more important than ever in the creation of robust, maintainable software.

It is anticipated that Russia will be one of the major suppliers of LNG to meet energy demand in Europe and in the US in the future. As a result large quantities of gas will be transported from Russia by sea in LNG ships. Due to the geographical location of large gas fields in Russia these LNG ships will need to be designed specifically to operate in severe weather conditions. Meeting the transportation challenge demands an analytical and a more comprehensive and systematic approach to the management of the risks. More detailed analysis has been made possible through developments in computing and modelling technology. That technology plays an essential role in addressing the key safety issues associated with emerging LNG transportation needs in Arctic trade. In addition the application of risk assessment methodology in the evaluation of novel concepts allows a better understanding of the risks associated with LNG shipping in arctic waters and its integration into design technical standards survey requirements and operational practices. Various aspects of the ship design and operational requirements are discussed from a Classification perspective. Particular consideration will be given to issues such as the strength of the hull structure to endure ice loads on deck ice-breaking capabilities and the design of the containment system to withstand the dynamic loads envisaged under harsh weather conditions in particular sloshing loads. In addition requirements for safety equipment and systems under freezing condition are addressed together with the propulsion systems for ships in this Design assessment of engineering systems with particular reference to shaft alignment

The detection of QPC (quadratic phase coupling) is an important problem in several contexts most notably in damping analysis of shock mounts design of optimal placement of machinery in plants and passive identification and classification of targets such as ships and submarines. The detection of QPC is necessary to determine if spectral lines at potentially coupled frequencies are indeed coupled. The problem of detection of QPC in a shallow underwater channel is addressed. The channel has been numerically modelled using normal mode theory. This paper addresses the problem of detection of QPC at a passive receiver when the source signal has traversed through an underwater channel. Extensive simulations have been carried out of the received signal of moving and stationary targets in shallow underwater channel to arrive at a robust algorithm for detection of QPC. The algorithm takes advantage of the slow variation of the bi-spectrum phase of the received signal which is due to the channel characteristics. Specifically the detector is based on the zero crossings of the bi-spectrum phase of the received signal across observation intervals. The proposed detector is observed to be robust in several typical shallow underwater channels. Detailed results of the detection performance of the algorithm in different SNR conditions are presented. The role of bi-spectrum in the detection of QPC is reviewed. The problem addressed is discussed. The signal model used to analyse the detector performance is presented followed by the QPC-detection algorithm. The simulation procedure is described and the simulation results are presentX45212 Detection of small man-made objects in sector scan imagery using neural networks

A NWT (numerical wave tank) for 3-D problems is developed. The motion of an ideal fluid and the motion of a floating body are simulated in a time domain. The BVP (boundary value problems) for velocity field and acceleration field are solved taking into account the interaction between the fluid and floating body motions. The QBEM (quadratic boundary element method) is used to solve these fields. Implicit boundary condition method is used for the acceleration field. Time integration is carried out with the RK4 (4th order Runge-Kutta method). Free surface is updated with the semi-Lagrangian time marching scheme. A double-node technique is used to properly update the intersections between the free surface and the body. Some calculations are carried out by the newly developed 3-D NWT and the following three cases are presented: 1 the simulation of 3-D waves in a circular wave basin; 2 the simulation of hydrodynamic forces on a sphere in forced heave motion; 3 the simulation of the free heave motion of a sphere in a circular wave basin.

NOx emissions from diesel engines are known to be a principal source of air pollution. In recent years global and local regulations for exhaust gas emissions in medium and large diesel engines used for power generation on land and propulsion system in vessels has become more stringent. Consequently engine makers have made every effort to meet the regulations. It is well known that when water is added to the combustion process NOx emissions are abated from decreased peak combustion temperature. Water can be introduced into the combustion chamber in various ways. A technique to moisturise charged air using water steam and packing block is studied. This offers a more effective means of moisturising charged air than the general water spraying method. This new water injection system is called a CAM (charged air moisturiser) system. The system is applied to SCDE and a medium-speed engine. The tests show very successful results. In applying the CAM system to the single cylinder diesel engine more than 66 per cent of NOx reduction rate was achieved with a maximum humidity of 66g per kg. The prototype CAM system for the HiMSEN engine showed a NOx abatement of 20 - 40 per cent with 20 - 39 g water per kg air humidity ratio. After the final optimising process the CAM system for HiMSEN engine is expected to show even better performance.

Throughout the oil industry vertical pipes are used to convey crude oil either offshore from the bottom of the sea or onshore from the depths under the soil. These pipes otherwise called risers are attached to a platform at one end and are buried under the seabed or in the ground at the other end. The stability of these pipes is the subject of this investigation. The history of such analysis dates back over five decades when the vibration and stability of fluid conveying Trans-Arabian pipeline network was first studied; albeit for an on-shore environment. For that case it was found that instability of the flow can be induced by vibration and that if such a horizontal conveyance pipe is supported at both ends it bows out and buckles when the flow velocity of the conveyed fluid exceeds a critical value. Because of the industrial relevance of such conveyance networks the problem has continued to generate interest over the years and especially now that deep waters offshore exploration is assuming increased importance in the Oil and Gas sector. When dealing with the stability of these pipes most workers usually assume the Euler-Bernoulli hypothesis which requires that plane sections perpendicular to the axis of the beam remain plane and perpendicular both before and after deformation. This essentially means that the deformation of such sections is neglected. However the Timoshenko hypothesis accounts for such deformation by including transverse shear which is usually neglected. In this paper the energy method is invoked to derive the governing equations including the effects of externa90509

Evaluation of hydrodynamic performance of two vessels in close proximity that are either stationary or advancing in waves is of paramount importance for many offshore and naval engineering applications. Hydrodynamic interactions between the vessels combined with non-linear mechanical interactions due to mooring and fendering systems make the problem more complicated. An efficient time-domain method is presented for evaluating the seakeeping and maneuvering performance of proximate vessels advancing with forward speed. The method computes the six DOF (degree-of-freedom) motions of a pair of hydrodynamically interacting vessels subject to wind waves currents and maneuvering effects at zero and non-zero speeds in regular or random seaways. Model tests carried out to validate the method are described and results presented. The validation efforts carried out so far have yielded satisfactory comparisons thereby reinforcing the confidence in the method and its applicability to such problems. The method has been used to predict safe operational limits of two vessels in skin-to-skin operations conducted by the US Navy. A similar analysis is presented for a different pair of vessels. Since it is based on time domain simulation this method also allows the inclusion of non-linear effects due to mooring lines fenders and effects of viscous roll damping which is not possible with two-body hydrodynamic interaction solutions in frequency domain.

In shipbuilding a ship hull structure is made of many ship hull blocks which consist of steel plates and stiffeners using welding in a shipbuilding dock. As one block weighs hundreds of tons holding it in a proper position with tolerable welding gaps and welding it to the neighbouring blocks take long time and many resources. Therefore the manufacturing accuracy of a block of a ship hull structure has a strong impact on the manufacturing costs. Accurate dimensions of a ship hull block with the minimal weld gap adjustment have been achieved in Japanese shipyards over the years using a knowledge database of weld shrinkage. However fierce competition in the shipbuilding industry is demanding a revolution of the conventional accuracy control system in Japanese shipyards in order to achieve weld-gap-adjustment free block erection in a dock. Research was carried out to develop an advanced accuracy control system. As a part of this coordinate measuring products were surveyed: a theodolite with a range meter; photogrammetry products with a film camera or with a digital camera; a laser scanner with an amplitude modulated laser beam; and a coordinate measuring machine using pattern recognition with a special probe. These products were evaluated by ease of use time required for measurement and measuring accuracy. Two measuring experiments revealed that a photogrammetry product the V-STARS system using a high-resolution digital camera is the best measuring method for ship hull production with some limitation in block size.

The longitudinal connections at the inner and outer hulls of ocean-going vessels often experience fatigue cracking as a result of dynamic stress fluctuations due to environmental loadings. A crack may begin at the area of stress concentration. It can then continue to grow through the longitudinal stiffener until it reaches the shell plate. Subsequently it creates a surface crack that goes through the plate. If this crack is not repaired it can grow to a critical size and may result in catastrophic structural failure. As a result it may induce structure failure and associated significant environmental impact and large financial losses. In view of previous studies on the fatigue analysis of ships and offshore structures shell elements are commonly used to calculate hot spot stress for complex connections. There are few studies using solid elements for longitudinal connections. Shell elements simulate only the mid-plane of a plate and weld is not modelled or modelled by some idealisations such as rigid links inclined shell element etc. This paper deals with a rigorous fatigue analysis using solid elements with full weld representation. A full-scale test of side longitudinal in FPSOs tested by DNV (Det Norske Veritas) is introduced and FE comparative studies are presented. After this effects of weld returns to connect two fillet welds and non-welded gaps in fillet weld are discussed. Finally

Continuing ocean experiments show specific applications in which a jellyfish-tracking ROV pilot assist enhances collection of scientific data. Recent results have repeatedly shown the tracker's ability to follow a jelly target for extended periods as long as 34 minutes. Thus far experimental demonstrations of the jelly tracker have incorporated a linear control law. The jelly-tracking controller is modified using extensions to the control law that enable two new capabilities. The first extension compensates for steady ROV disturbances. The second extension gives pilots full authority in the null space of the jelly-tracking regulation law. Bias compensation serves to smooth transition from human pilot to combined computer-human control and to establish a clear zero reference for supplementary pilot commands issued during tracking. Use of the regulator null space enables the pilots to view the target from multiple angles. The jelly-tracking system used in ocean trials is reviewed together with its linear control law and the results of recent ocean experiments with MBARI ROV Ventana. Then extensions to the fielded system are examined which are intended to improve interaction between automation and human control. Next the ROV dynamic equations are presented. An estimator is presented. This is based on these dynamic equations which can smooth transition during system initialisation. A control framework is proposed which allows the human pilot to command large motions in the regulation law null space.