Grounding in a wind power application

The subject of this master’s thesis is to research grounding in a particular wind power application. The aim is to define how the grounding from different points effects to the function of the whole system. The investigated subjects are generator voltage spikes, ground currents and system fault situations. The first part of this thesis represents power electronics, which is commonly used in wind power systems. The second part concentrates more to the grounding, electrical safety demands and potential fault situations. The object of the simulations is to investigate voltage spikes and fault situations. Measurements will be made with small-scale setup and in the last part simulation and measurement results are compared to each other and to a full-scale system.

DFM(A)-Aspects of an Advanced Cable Gland Design

Nowadays typical motor junction boxes do not incorporate cable glands, which would provide good electrical performance interms of electromagnetic compatibility. In this paper, a manufacturability and assembly analysis for the new construction of a rigid body feeder cable junction of an electric motor is presented especially for converter drives (practical tests were carried out at LUT during 2007). Although the cable junction should also clamp the cable to provide enough tensile strength, the phase conductors should not get squashed by the groundingconnection. In order to ensure good performance in an electrical mean especially in converter drives, the grounding of the cable should be connected 360 degrees around the cable. In this paper, following manufacturing technologies are discussed: traditional turning, precision and centrifugal casting, and rotation moulding. DFM(A)-aspects are presented in detail.

Efficient installed base information management and utilization in global after sales service business

This Master´s thesis explores how the a global industrial corporation’s after sales service department should arrange its installed base management practices in order to maintain and utilize the installed base information effectively. Case company has product-related records, such as product’s lifecycle information, service history information and information about product’s performance. Information is collected and organized often case by case, therefore the systematic and effective use of installed base information is difficult also the overview of installed base is missing. The goal of the thesis study was to find out how the case company can improve the installed base maintenance and management practices and improve the installed base information availability and reliability. Installed base information management practices were first examined through the literature. The empirical research was conducted by the interviews and questionnaire survey, targeted to the case company’s service department. The research purpose was to find out the challenges related to case company´s service department’s information management practices. The study also identified the installed base information needs and improvement potential in the availability of information. Based on the empirical research findings, recommendations for improve installed base management practices and information availability were created. Grounding of the recommendations, the case company is suggested the following proposals for action: Service report development, improving the change management process, ensuring the quality of the product documentation in early stages of product life cycle and decision to improve installed base management practices.

Survey of transportation of liquid bulk chemicals in the Baltic Sea

This study is made as a part of the Chembaltic (Risks of Maritime Transportation of Chemicals in Baltic Sea) project which gathers information on the chemicals transported in the Baltic Sea. The purpose of this study is to provide an overview of handling volumes of liquid bulk chemicals (including liquefied gases) in the Baltic Sea ports and to find out what the most transported liquid bulk chemicals in the Baltic Sea are. Oil and oil products are also viewed in this study but only in a general level. Oils and oil products may also include chemical-related substances (e.g. certain bio-fuels which belong to MARPOL annex II category) in some cargo statistics. Chemicals in packaged form are excluded from the study. Most of the facts about the transport volumes of chemicals presented in this study are based on secondary written sources of Scandinavian, Russian, Baltic and international origin. Furthermore, statistical sources, academic journals, periodicals, newspapers and in later years also different homepages on the Internet have been used as sources of information. Chemical handling volumes in Finnish ports were examined in more detail by using a nationwide vessel traffic system called PortNet. Many previous studies have shown that the Baltic Sea ports are annually handling more than 11 million tonnes of liquid chemicals transported in bulk. Based on this study, it appears that the number may be even higher. The liquid bulk chemicals account for approximately 4 % of the total amount of liquid bulk cargoes handled in the Baltic Sea ports. Most of the liquid bulk chemicals are handled in Finnish and Swedish ports and their proportion of all liquid chemicals handled in the Baltic Sea is altogether over 50 %. The most handled chemicals in the Baltic Sea ports are methanol, sodium hydroxide solution, ammonia, sulphuric and phosphoric acid, pentanes, aromatic free solvents, xylenes, methyl tert-butyl ether (MTBE) and ethanol and ethanol solutions. All of these chemicals are handled at least hundred thousand tonnes or some of them even over 1 million tonnes per year, but since chemical-specific data from all the Baltic Sea countries is not available, the exact tonnages could not be calculated in this study. In addition to these above-mentioned chemicals, there are also other high volume chemicals handled in the Baltic Sea ports (e.g. ethylene, propane and butane) but exact tonnes are missing. Furthermore, high amounts of liquid fertilisers, such as solution of urea and ammonium nitrate in water, are transported in the Baltic Sea. The results of the study can be considered indicative. Updated information about transported chemicals in the Baltic Sea is the first step in the risk assessment of the chemicals. The chemical-specific transportation data help to target hazard or e.g. grounding/collision risk evaluations to chemicals that are handled most or have significant environmental hazard potential. Data gathered in this study will be used as background information in later stages of the Chembaltic project when the risks of the chemicals transported in the Baltic Sea are assessed to highlight the chemicals that require special attention from an environmental point of view in potential marine accident situations in the Baltic Sea area.

Perspectives on narrative discourse markers : focus on Old English þa

Ett element som har intresserat forskarna av fornengelska sedan början av filologiska studier är adverbet þa ’då’, som är högfrekvent i många berättande texter. Utöver ordföjldsregeln enligt vilken satsinitialt þa följs av omvänd ordföljd, finns det redan tidigt kommentarer om användningen av þa för emfas, livlighet och konnektivitet. Även om sådana karakteriseringar tar den textuella kontexten i beaktande, är deras fokus inte på diskursfunktioner utan på satsgrammatik. Denna avhandling betraktar användningen av þa från diskursstrukturens perspektiv och undersöker dess funktioner i markeringen av berättelsens huvudlinje (eng. grounding), kohesiva kontinuiter (eng. continuities), samt vändpunkter och spänning (eng. peak, tension) i texten. I stället för att fokusera på bara en funktion som har associerats med þa, undersöks denna frekventa element från olika perspektiv. Genom både kvantitativa och kvalitativa analyser av narrativt material, visar de inkluderade delstudierna att detta ord spelar en viktig roll i struktureringen av fornengelska berättelser. Parallellt med kärnfunktionen att markera berättelsens huvudlinje, används þa i samspel med andra strukturerande element för att uttrycka den hierarkiska strukturen och spänning i berättelsen. Jämförelser med andra uttryck av temporal kontinuitet visar att þa skiljer sig från dem i sina användningsmönster, vilket vidare bekräftar dess status som en narrativ diskursmarkör.

Ohjelmistoradion hyödyntäminen tiedonsiirron tutkimisessa LVDC-verkossa

Työssä tutkitaan tiedonsiirtoa eri modulaatioilla, bittinopeuksilla ja amplitudin voimakkuuksilla ja tuloksia tarkastellaan Bit Error Ration avulla. Signaaleja siirrettiiin myös koodattuna ja vertailtiin koodauksen etuja ja haittoja verrattuna koodaamattomaan tietoon. Datavirta kulkee AXMK-kaapelissa, joko tasasähkön mukana, tai maadoituskaapelissa. Tuloksissa havaittiin, että suurempi bittinopeus ei kasvattanut häviöiden määrää. Koodauksen käyttö toisaalta vähenti bittivirheiden määrää.

Kriittisyysanalyysin kehittäminen kemianalan tuotantolaitokseen

Tutkimuksen tarkoituksena oli löytää menetelmä, jolla löydetään tuotannon kannalta kriittiset laitteet. Vertailu suoritettiin suomalaisen PSK 6800-standardin ja saksalaisen DIN standardin mukainen BASF:n laatiman Risk-based Maintenance concept:n välillä. Tutkimuksessa kehitettiin tehtaan tarpeisiin soveltuva kriittisyysanalyysi. Tarkoituksena oli kehittää tehtaalle ominaisilla tunnusluvuilla soveltuva analysointimenetelmä. Tehtaan kunnossapidolta kerätyn pohjatiedon avulla laadittiin kriittisyysanalyysi. PSK-6800 standardin pohjalle kehitetty kriittisyysanalyysi testattiin ja vertailtiin BASF:n mallin mukaisesti kehitetyn kriittisyysanalyysin tuloksiin. Analysointi suoritetaan tuotantoprosessin alkupään laitteistolle. Kahden kriittisyysanalyysin tulokset ovat yhtenevät. Tuotantolaitos voi valita kahdesta kriittisyysanalyysistä tarpeisiinsa sopivan analysointi menetelmän.