bluuebunny/crossref_metadata_2025_split huggingface dataset:
Testing and Certification in Europe
Authors: Gundlach H.C.W. 
Published: October 2008

ABSTRACT
In 1.985 a "White Paper" was published by the European Commission concerning the creation of a single market, with free movement of goods, services, people and capital within the European Community. It was clear that differences in standards, tests and certification created barriers to trade. To 1.evel down these barriers to trade a "New Approach" was started and a CE-mark was introduced. This mark for products is a tool to cross the borders but not a sign of quality.

INTRODUCTION
In Europe technical barriers to trade have arisen for a variety of reasons, one of them being the legislative requirementsof different Member states protecting the health and safety of their people. Also a wide variety of other non-legislative reasons ranging from simple purchaser preference, through the use of local standards, to insistence on local testing and certification build up serious barriers. (Fig. 1)
Elimination of these barriers to trade is dictated by their nature, whether they are in the regulated/ mandatorysector, that is to say due to legislation, or are due to some other reason. To gain a clear insight into the industry'sview on different types of barriers to trade, a questionnaire was sent out to over 20.000 companies in all 1.2 Member states of the European Community. The questionnaire was inquiring how the companies evaluated the barriers to trade as a whole. The different barriers to trade were rankedas follows:Technical standards and regulationsAdministrative barriersFrontier formalitiesFreight transport regulationsValue-added tax referencescapital market controlGovernment procurement restrictionsImplementation of Community law
Technical regulations were thus considered by the industrialists as the most important single category of barriers to trade. Also repeated testing and certification of the same product in different Member states constitute technical barriers in the common market. In order to level down the legal barriers to trade, in 1.985 the Council of Ministers agreed a resolution on a"New Approach to Technical Harmonisation and Standards". The New Approach Directives set out "Essential Requirements" which stipulate in broad terms must be achieved in order to protect health, safety and environment, rather than how it should be achieved.A product must satisfy the Requirements of all relevant Directives before it can be placed on the market.
A Directive is legally obliging Member states to implement the regulations in national laws. The broad nature of the "Essential Requirements", together with majority voting introduced under the New Approach, makes agreement on the continent of Directives more straightforward and allows greater flexibility in product development.
In recognising the diversity of testing, inspection and certification activities, the EC has drawn up a series of standard conformity assessment techniques, known as "Modules", for use in the New Approach Directives. Theserange from manufacturer declaration, through a variety of routes involving design and type approval, to full third party certification..
Low-Frequency Motions of Tankers on Tandem Offloading Condition
Authors: Feikema G.J. , Huijsmans R.H.M. , Aalbers A.B. 
Published: October 2008

ABSTRACT
In this paper a number of hydrodynamic aspects of tandem mooring operations of floating VLCCS will be discussed. The effect of shielding of the wind and current on the export tanker are established by means of model test experiments. The interaction of two floating vessels on the wave drift forces exerted on each other is treated by means of potential theory calculation methods. One of the findings of this study is that the current loads and wave drift forces on the export tanker are reduced with respect to the undisturbed case, provided that the F(P)SO heading angle is close to 180 deg. However, for larger heading angles even an increase of the longitudinal forces on the export tanker can be observed.

INTRODUCTION

Tandem Mooring
Nowadays, oil off loading from storage tankers is common practice due to the presence of several dozens of tanker-based FpSOS and FSOS moored at sea. With the in Creasing number of marginal fields in development it may be expected that more (easily transferable)tanker-based F(P)SOS will follow.
For the economy of the oil production system it is beneficial if the 'weather window? for oil offloading is large: an export or off take (OT) tanker should be able to stay connected and keep loading in relatively high sea states.
Model tests and experience have learned that a tandem mooring arrangement can be maintained in higher sea states than a side-by-side mooring, so that all present F(P)SO designs assume that offloading takes place by an export tanker which is hawser moored to the F(P)SO stern.

Operability
The limitations for the operability of tandem off loading are determined by two aspects:The low frequency drift motions of the export tanker with respect to the F(P)SO, which may be due to wave drift forces as well as galloping (mooring instability).The wave induced (high frequency)relative motion between the two tankers in way of the bow hawser, at the time that the low frequency excursion is at a maximum.
Improvement of the operational limits of tandem offloading has been focused on optimization of bow hawser characteristics and bow hawser length. Properly chosen elasticity will help reduce the peak loads due to the second aspect mentioned above, while a properly chosen bow hawser length will avoid galloping, ref. [1] and [2].
Still, low frequency 'fishtailing? motions of the export tanker form the basis for the limitations in the operability of tandem moored offloading. Modern methods to improve on this are in development: thruster assisted bow hawser mooring and dynamically positioned(DP) offloading. In thruster assisted mooring the bow (tunnel) thrusters of the export tanker are used to maintain a good alignment of the bow hawser, whilst the main propeller provides some astern thrust to avoid slack. In DP offloading the bow hawser is not necessary: an automatic thruster control system takes care that the tanker keeps position behind the F(P)SO, [3].
Operation of a Dynamic Positioning Offshore Vessel
Authors: Reinertsen V. , Halvorsen C.P. , Alvheim N. 
Published: October 2008

ABSTRACT
This paper describes the criteria used in the design of a dynamically positioned vessel. There are two main criteriaClass RegulationsGuidelines including the user's particular requirements
This paper is presented in four parts:Experience in Operating DP Controlled Vessels,Comparison between DP and Anchor Mooring Controlled Operation both using a Monohull Vessel,The Basic Design Philosophy for all DP Vessels with the Class Notation "DYNPOS".Description of a Latest Generation DP Vessel with the DnV Class Notation "AUTR" and Corresponding ERN 99.99S9.

EXPERIENCE IN OPERATING DP CONTROLLED VESSELS
Ugland Companies have been involved in the design and operation of DP vessels since 1976, including specialised offehore installation vessels and shuffle tankers. Considerable experience has bean gained in the intervening years, all of which haa been put to good effect in the specification for the Ugland Maxita described in this paper.
However, the technological developments have been further advanced in the design of a duel purpose vessel currently under construction. She will incorporate the greatest DP control capability of any installation vessel and hence will offer the maximum operational flexibility in the offshore industry during the Summer months,
Advanced features will include:Open System ArchitectureMan/Machines InterfaceDecision Support
The design of the vessel has been accomplished as a result of cooperation between Ugland and the Finnish National 6oard of Navigation who are the Owners,
During the Winter months, she will be employed as an Icebreaker in Finnish waters; In this capacity she will also provide the most efficient service available,
The use of dynamically positioned vessels, and their application, has increased tremendously during the last 10 years, The flexibility of this type of vessel is substantial, as is the benefit to the user. The standard and complexity of the systems available has improved, and redundancy has become a key issue. Systems today have a high level of safety, and from a technical point of view, reliable operation are to be expected.
In the past, more than 50% of all DP "accident" have been due to human error on the part of the operator of the DP system. However, under current Rules In the North Sea, certification of the DP operator is a mandatory requirement, and this is a step in the right direction. On board the vessel, the system require highly skilled operators and service personnel,
Consequential analysis performed on-line by the computer, and based upon worst case failure, Is now a standard requirement during operation, This provides a good operational guideline for the operator

COMPARISON BETWEEN DP AND ANCHOR MOORING CONTROLLED OPERATION BOTH USING A MONOHULL VESSEL
The main objective for all parties involved in offshore work is to make the operations as safe as possible. The safe working limits for each activity are based upon this fundamental principle.
Drag Embedment Anchor Performance Prediction in Soft Soils
Authors: Stewart W.P. 
Published: October 2008

ABSTRACT
A rational approach to calculating the drag embedment performance of marine anchors in cohesive soils is presented. The method considers the geotechnical and gravity/buoyancy forces acting on all components of the anchor system including various areas on the anchor and the attached mooring line which may be either chain or wire. The solution proceeds in a piece-wise linear manner until an equilibrium position is found for the anchor. This equilibrium position is described in terms of the anchor burial depth, the anchor drag distance, and an anchor angle of rotation in the soil. The equilibrium position may be such that the anchor holds the applied line load and no further movement occurs, or it may be such that the anchor can dig no deeper and horizontal movement is predicted with a given maximum resistance.
The solution technique requires a computer program. Such program has been developed and the results from the program have been compared with large scale tests performed in the Gulf of Mexico in 1990.

HISTORICAL ANCHOR DESIGN
This paper is concerned primarily with relatively large marine drag embedment type anchors which areused in the offshore industry. However, it is worth considering the evolution of anchors in general. The first patent that was filed for describing an anchor was that by Hawkins in 1821. This patent described an anchor consisting of two flukes which were articulated about a pin perpendicular to the shank of the anchor. This concept has remained in use today and falls now into two main categories of stockless anchors and stock anchors.
Stockless anchors are widely used today on warships and on merchant ships. They are not typically used inthe offshore industry.
Articulated stock anchors are more widely used incommercial applications today than stockless anchors. The Danforth anchor is a typical example developed in the late 1930s. These anchors are used on barges and semi-submersible drilling rigs. Names in common use include Danforth, LWT, and Offdrill.
The requirements of the offshore industry to provide ever larger capacities of anchors led to a scaling up ofexisting models. Stockless and stock anchors weighing up to 30 tons in air have been built. Special anchor handling vessels have been developed specifically for the placement and retrieval of these anchors. In the last decade, the increasing use ofpermanent mooring systems for floating production has resulted in the design of anchors specialized to certain types of soil conditions. In the soft cohesive soils typical of many deep water areas in the world, increasing use of anchors fabricated from steel plates has occurred. These fabricated anchors replace cast steel anchors. They are more efficient in terms of their holding capacity compared to their weight. However, they are very specific to individual applications and cannot be regarded as general purpose anchors.
The Disconnectable Mooring System Of The FPSO Vessel At Huizhou, South China Sea, Lives Up To Its Promises
Authors: Dodelin Daniel Forest 
Published: October 2008

ABSTRACT
The system chosen to develop the HZ-21 and HZ26 oilfield offshore the People's Republic of China was a tanker based FPSO incorporating an innovative disconnectable mooring design to allow the tanker to leave the area in the event of an approaching typhoon. This paper gives an outline of the design and construction, and describes the installation and first 18 months operational experience.

INTRODUCTION
The HZ-21 and HZ-26 fields, jointly developed by the ACT OPERATORS GROUP (ACT-OG) comprising Agip, Chevron, Texaco and the Chinese NanhaiEast Oil Corporation, lies in the South China Sea approximately 100 miles S.E. of Hong Kong in 116 meters of water.
The area is notorious for typhoon conditions where a combination of wind, wave and storm driven currents result in far more severe weather conditions than encountered, for instance, in the North Sea.
However, the seasonality, low frequency andpredictability of typhoons made the choice of a disconnectable rather than permanent mooring system more attractive. In addition to the relative costs, down time due to disconnection would be minimal since the production facility in the field required evacuation and hence production would be halted in any case.
The system involved locating an internal turret inthe forepeak structure of the FPSO supported by a three race roller bearing allowing the tanker to weathervane around the mooring (refer to Figure 1). Connection of the turret to the submerged mooring buoy carrying the eight catenary anchor legs is effected by means of a mechanical connector once the mooring buoy has beenwinched up to the tanker from its neutral buoyancy position 35 m below mean sea level (refer to Figure 2).
The design concept is described in greater detailin OTC 6251, Innovative Disconnectable Mooring System for Floating Production System of HZ-21-1 Oil Field at Huizhou, South China Sea, while SPE 22377, First 12 Months' Experience of Disconnectable Mooring System for HZ-21/HZ-26 FPSO, gives a review of the first year of operation of the system.

MOORING SYSTEM
The Buoyant Turret Mooring (BTM) was designed to allow reconnection in 3.5 m significant sea states. As with any disconnectable mooring system there are three major elements:the mooring buoy which carries the risers and the anchor legs,the turret around which the tanker weathervanes,the swivel which provides the connectionbetween the earthbound risers and the piping on the rotating tanker.

Mooring Buoy
The mooring buoy carries the eight catenary anchor legs, comprising of wire rope and chainterminated with a high holding power anchor as well as the risers from the production platform. The buoy is of novel design since the buoyancy is controlled to allow the buoy to sink, when disconnected, to a depth of 35 m where the net buoyancy is equal to the suspended weight of the chains and risers.
Sliding Mode Acoustic Servoing for an Autonomous Underwater Vehicle
Authors: Marco D.B. , Healey A.J. 
Published: October 2008

ABSTRACT
Currently in use at the Naval Postgraduate School is a fully functional experimental autonomous underwater vehicle (AUV). The vehicle serves as a test bed for research in autonomous control, autonomous obstacle avoidance, automatic fault detection, guidance and control at slow speed. It measures over seven feet (two meters) in length and weighs about 430 pounds (215 kg). Maneuvering control is provided by four rudders and dive planes, has twin propulsion motors, and onboard sensors for speed, depth, angular rates and positions and four ultrasonic sensors for range information. All shipboard action is controlled by a 68030 microprocessor running under an OS-9 operating system and a G-96 bus with code written in 'C' language. All systems are powered by lead acid gell batteries for a test mission duration of about two hours.
This paper presents some experimental modeling results upon which computer simulations of the dynamic positioning performance are based. Details are given of the vehicle modeling, the influence of thruster dynamiclags, Sliding Mode control design including integral control for the compensation of ocean current effects, and a Kalman filter design for the estimation of target range and velocity from noisy sonar data. The filter can remove transient fault anomalies which are common insonar data.

INTRODUCTION
This paper provides an analysis of the effects of ocean current, thruster dynamic lags and acoustic sensor noise on the motion control of an underwater vehicle in the longitudinal direction. The context and importance of this work lies in the increased use of ROV's for deep ocean intervention and inspection tasks. With the ever increasing emphasis on reduction of costs, it is the contention of the authors that the use of fully autonomous vehicles will be needed for routine underwater jobs because they can be deployed from platforms and will not need the support of expensive surface assets. One of the missions foreseen for vehicles of this type is to provide inspection of underwater facilities. Motion control using onboard sonar to 'servo'to a target will be a typical operation.
Current research at NPS and elsewhere is aimed at designing robust controllers for underwater vehicles, the slow speed behavior of which are highly uncertain. The robust control of ROV's has been addressed by Yoerger and Slotine (1985), and the design and operation of the Jason supervisory control system hasbeen described by Yoerger et. al. (1986), in which a surface operator drives the vehicle using a manual teleoperated link from a surface ship. More recently, Fossen (1991) has studied the same subject. At NPS we are exploring the behavior of fully autonomous underwater vehicles which are programmed prior to launch and for which there is no tether. After recovery, the data stored on board is uploaded for data visualization and postprocessing. All mission functions are controlled by the onboard autonomous controller..
Testing Program Probes Capabilities and Potentialities of TFL Systems
Authors: Chioetto Stefano , De Ghetto Giambattista 
Published: October 2008

ABSTRACT
In autumn 1991 AGIP concluded a test campaign on 3 in. Through Flow-Line (TFL) equipment, at a purpose-built test-site at Cortemaggiore, Italy. Testing included over 220 runs in a live onshore well, using a large number of different tools and functions.
TFL Side-Pocket Gas Lift and Jet Pump installation and operation techniques were also tested.
This article is a concise summary of the results and conclusions of the project.
Potential prospects for the future of TFL systems are evaluated in the light of present trends in offshore productiondevelopments and existing alternatives to TFL.

INTRODUCTION
Long-term .trials on 3 in. TFL equipment and procedures were run by AGIP for 3 years, at a test facility built for the purpose in Cortemaggiore, Italy (Figs. 1, 2). The site was set up next to an old, depleted oil well that had watered out and was recompleted to accommodate TFL for testing purposes (Fig. 3). Test operations were organized in two phases:the preliminary phase (March 1988, April 1990) of tests on the surface, where the various tools and operations were tested in a short flow-line loop (280 m.) and in a horizontal mock-up TFL well completion;the main phase (July 1990, June 1991), where the tools and operations weretested in the well.
OTC paper 6433 offers a thorough description of the test facilities, andsynthesizes the results from the preliminary phase of surface tests 1. The present article is the sequel to that first paper, and describes the second phase of the testing, performed in Well Corte 57.

Well and reservoir characteristics
A Residual Oil Saturation test performedin the Spring of 1990, just before the work-over to re-complete Well Corte 57 for TFL testing, yielded the following data:Water Cut - 100 % approx.;Salt concentration of formationwater - 210 gr/l;Static BHP - 2767 psi;Static THP - 41 psi;Static BHT - 52°C;P.I. - 1.4 (m3 /d)/(kg/cm2);Sand volume fraction - 1% approx.
The well completion specifications are as follows (Fig. 4):vertical well;Perforated interval = 1740 - 1745 m.;Inner casing profile = 9 5/8 in. 1.0. to 1448 m.; 6 5/8 in. 1.0. liner from1047 m. to bottom.
The well completion is composed of a double TFL string, 3 1/2 in. * 3 1/2in., down to the depth of 1009 m., where an H-Member Cross-Over Head provides the lowest circulation point for TFL operations. Below this:the "primary" string follows as a 3 1/2 in. TFL string down to the Foot-Valve (1029 m. depth), and, from there on, as a non-TFL single string to the perforations; a prepack screen is installed at the bottom of the string to protect TFL tools from sand;the "secondary" string follows to the depth of 1017 m, where it ends with a No-Go type KN Landing Nipple.