Graduation date: 1999

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references. Also available in electronic version.

Thesis (Ph.D.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 129-136.

Thesis (Ocean E)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1982. / Supervised by J. Kim Vandiver and Henri O. Berteaux. Includes bibliographical references (leaves 151-153).

Problem: Leveranser av IT tjänster från lågkostnadsländer till Sverige. Syfte: Att ta reda på hur svenska företag ser på leveranser av IT tjänster från lågkostnadsländer och ta reda på vilka drivkrafter och hinder som existerar. Eftersom Indien är det land som står för de största volymerna vad gäller produktion av IT tjänster så blir det naturligt att fokusera mest på det landet. Teori och modell: Idag produceras hälften av världens IT tjänster i Indien. Svenska företag ligger ungefär tre år efter sina brittiska och amerikanska kollegor vad gäller att köpa IT tjänster från Indien. Metod: Vi valde en kvalitativ metod för att få fördjupad information kring ämnet och genomförde nio intervjuer med olika svenska företag. Förutom dessa intervjuer hämtade vi data från publicerade artiklar. Resultat: Vår undersökning visar på att Indien är ett land att satsa på vad det gäller leveranser av IT tjänster. Att hitta tillräckligt stora IT projekt för att Indien ska ses som lönsamt, verkar vara det främsta hindret. Kompetensen i Indien och kostnadsreduktion är de starkaste drivkrafterna.

Proper selection of drilling fluids plays a major role in determining the efficient completion of any drilling operation. With the increasing number of ultra-deep offshore wells being drilled and ever stringent environmental and safety regulations coming into effect, it becomes necessary to examine and understand the behavior of water based drilling fluids - which are cheaper and less polluting than their oil based counterpart - under extreme temperature and pressure conditions. In most of the existing literature, the testing procedure is simple - increase the temperature of the fluid in steps and record rheological properties at each step. A major drawback of this testing procedure is that it does not represent the continuous temperature change that occurs in a drilling fluid as it is circulated through the well bore. To have a better understanding of fluid behavior under such temperature variation, a continuous test procedure was devised in which the temperature of the drilling fluid was continuously increased to a pre-determined maximum value while monitoring one rheological parameter. The results of such tests may then be used to plan fluid treatment schedules. The experiments were conducted on a Chandler 7600 XHPHT viscometer and they seem to indicate specific temperature ranges above which the properties of the drilling fluid deteriorate. Different fluid compositions and drilling fluids in use in the field were tested and the results are discussed in detail.

Until today the offshore wind power has grown in a steady pace and many new wind farms are being constructed around the globe. An important factor that is investigated today in the industry are the security of power supply to the equipment needed for controlling the offshore system during emergency situations. When a offshore wind farm is disconnected from the external grid and an emergency case occur the wind turbine generators lose their ability to transfer power and they are forced to be taken out of operation. As there are a number of loads in the wind turbines (navigation lights, sensor- and communication-apparatus, ventilation- and heating equipment etc.) they have a load demand which must be supplied in emergency mode. The German Transmission System operator (TSO) TenneT GmbH has set a requirement that the wind turbines is to be supplied by an auxiliary power supply (APS) in 12 hours and therefore there is need for a long-term auxiliary power supply system. This master thesis was assigned to investigate the most feasible APS-system. From the study of a number of different APS's one concept was chosen. This was the diesel gen-set solution placed on an offshore substation at sea. The system was modeled in the software DIgSILENT PowerFactory where a load flow analysis validated the calculated data and a study of the impact of  transients in the system was performed.

A rapid development of offshore wind power is planned in GB as a part to fulfil the EU2020 targets. 25 GW wind power capacity has been awarded to developers in nine different offshore zones outside the coast of UK. VSC-HVDC transmission is expected to be a both technical and economical favourable solution for transmitting the power into the main grid. This study investigates if such a transmission solution could comply with the regulatory framework in UK. Vattenfall and Scottish Energy Renewable will be part of this development and have been awarded the rights to develop 7200 MW of wind capacity outside the cost of East Anglia as a part of the offshore expansion plans in UK. The zone is broken down to several projects. The first project is called East Anglia ONE and this project is used as a reference case in this study. The GB Grid Code has been broken down into four areas, voltage and frequency variations; fault ride through requirements, active power control and reactive power control. Load flow calculations and dynamic simulations are designed to investigate compliance of each area. Further, simulations to investigate the interaction between the wind turbines and the offshore converter stations where done. A model representing East Anglia ONE was built in PSS/E and used to investigate grid codes compliance by load flow calculations and dynamic simulations. Data from earlier studies at Vattenfall was used to get a good representation of the wind park. A model representing a HVDC-transmission solution was provided by ABB. The results from load flow calculations and simulations show that a HVDC-solution can comply with the investigated parts of the grid codes. The limiting factor seems to be the capability to inject enough reactive power to the gird at small voltage dips during normal operation. This capability can, however, be enhanced with the right tap-changer settings at the onshore converter transformer.

Die Herstellung großer, dickwandiger Schweißkonstruktionen ist durch einen hohen fertigungstechnischen Aufwand gekennzeichnet. Dieser erhöht sich mit zunehmender Bauteilgröße in überproportionalem Maße. Mit dem Beginn der Fertigung von Gründungsstrukturen für Offshore-Windenergieanlagen, stellt sich die Frage nach der Automatisierung schweißtechnischer Prozesse neu. Im Rahmen einer Machbarkeitsstudie wurde ein schienengeführtes traktorähnliches System entwickelt. Der folgende Pro Engineer Anwendervortrag umfasst das Erstellen dreidimensional geformter Schienensegmente. Weiterhin wird das Gesamtsystem der schweißtechnischen Automatisierung, bestehend aus Schweißtraktor und Schiene, mit Hilfe von Gelenkverbindungen in Pro Engineer zu einer zwnagsläufigen räumlichen Kinematik verbunden. Außerdem wird die Fahrt des Schweißtraktors entlang der Schweißfugenkontur an Hand einer Animation gezeigt, welche mit Pro Engineer DAO (Design Animation Option) erstellt wurde.

For an offshore platform structure applied to wave-energy conversion system, in order to catch the maximum waves to generate more powers, similar to wind-energy power generators, a range of angles for the devices normal to the propagating direction of incident waves is required, particularly when the power converting system has directional preference. In this study, an electro-magnetic wave energy conversion device was developed and tested in a single-mooring offshore platform system. In order to find the best design parameters for the electro-magnetic generators system in various wave periods a water-tank experiment was designed and performed. During the experimental study, both wave parameters and dimensional related parameter of the generator were under investigation. It was found in this study that the newly developed wave conversion system can work well under certain periods and height of waves. The relationships between the parameter were presented into figures.