Permanent magnet synchronous generator design solution for large directdrive wind turbines: Thermal behavior of the LC DD-PMSG

Wind is one of the most compelling forms of indirect solar energy. Available now, the conversion of wind power into electricity is and will continue to be an important element of energy self-sufficiency planning. This paper is one in a series intended to report on the development of a new type of generator for wind energy; a compact, high-power, direct-drive permanent magnet synchronous generator (DD-PMSG) that uses direct liquid cooling (LC) of the stator windings to manage Joule heating losses. The main param-eters of the subject LC DD-PMSG are 8 MW, 3.3 kV, and 11 Hz. The stator winding is cooled directly by deionized water, which flows through the continuous hollow conductor of each stator tooth-coil winding. The design of the machine is to a large degree subordinate to the use of these solid-copper tooth-coils. Both steady-state and timedependent temperature distributions for LC DD-PMSG were examined with calculations based on a lumpedparameter thermal model, which makes it possible to account for uneven heat loss distribution in the stator conductors and the conductor cooling system. Transient calculations reveal the copper winding temperature distribution for an example duty cycle during variable-speed wind turbine operation. The cooling performance of the liquid cooled tooth-coil design was predicted via finite element analysis. An instrumented cooling loop featuring a pair of LC tooth-coils embedded in a lamination stack was built and laboratory tested to verify the analytical model. Predicted and measured results were in agreement, confirming the predicted satisfactory operation of the LC DD-PMSG cooling technology approach as a whole.

Collective redundancies in the State of California of the United States and in the Republic of Finland. Procedures and Provisions

Video games industry has recently bonded California and Finland in a new way and where the employers are recruiting they also need to be aware of the provisions and procedures related to terminations. In general, collective dismissals are on a relatively high level both in Finland and in California. In California, collective redundancies are regulated under the WARN law. The WARN obligates employers with 75 or more employees to give a 60-day notice prior to a mass lay off and some other similar events. Employers with less than 75 employees are free to administer the terminations without the WARN notice period. Generally, the California at-will presumption allows employment relationship to be terminated any day with or without reason and without notice period if conditions of collective agreements or employment contract do not limit this right. Termination cannot anyhow be in violation of the anti-discrimination law. In Finland the termination related provisions are part of the Employment Contracts Act and the Act on Co-operation within Undertakings. Collective redundancies are allowed under financial and production related grounds. Small employers with less than 20 employees follow the termination provisions of the Employment Contracts Act and are obligated to inform the employee to be terminated on the details of the termination itself and also the services of the Employment and Economic Development Office. Employers with 20 or more employees are to initiate co-operation procedure under the Act on Co-operation within Undertakings when reducing personnel. The co- operation negotiations are to inform employees on the employer’s plans and financial situation as well as to involve them in the decision making regarding the terminations. The employer’s duty to inform the employees of the services of Employment and Economic Development Office needs to be fulfilled also in terminations under the co-operation procedure. Discrimination is prohibited in Finland in terminations of employment. As an alternative for terminations, employees can for example be transferred to another position or be temporarily laid off. Employer’s duties related to search of alternatives for layoff are broader in Finland than in California. The recent development of the labor laws in Finland and in California suggests that the labor law is not static in either one of these environments but changes can be expected as the needs of the business life so require.

Robottihitsauksen toimintojen kehittäminen hitsaustuotannossa

Tämän diplomityön tarkoituksena oli kehittää robottihitsauksen toimintoja KKR Steel Oy:ssä. Tärkeimmät tutkimuskohteet olivat robottisolujen toiminnan tehostaminen ja uusien robottihitsaukseen sopivien tuotteiden kartoittaminen. Työ on jaettu teoreettiseen ja käytännön osuuteen. Teoriaosassa perehdytään kirjallisuuskatsauksen kautta robottihitsauksen perusteisiin, hitsauksen robotisointiin sekä tuottavuuteen ja laatuun. Robottihitsauksen osuudessa käsitellään hitsausrobotin rakennetta, siihen liittyviä oheislaitteita ja robottien ohjelmointia. Hitsauksen robotisoinnissa selvitetään syitä robottihitsauksen käyttöönotolle, robotisoitavilta tuotteilta vaadittavia ominaisuuksia sekä erilaisia toimenpiteitä robottiaseman toiminnan tehostamiseksi. Tuottavuuteen liittyvässä osuudessa selvitetään erilaisten laskentakaavojen ja tunnuslukujen käyttöä ja merkitystä hitsauksessa. Käytännön osuudessa kartoitettiin yrityksen robottihitsauksen lähtötilanne ja selvitettiin ongelmakohtien perusteella kehittämistoimenpiteitä. Tutkimuksissa seurattiin ja havainnoitiin hitsaustuotannon eri vaiheita, minkä perusteella laadittiin erilaisia parannuskeinoja. Toimenpiteistä saatavan hyödyn arviointiin käytettiin yrityksen tuotantoon sopivia mittareita kuten läpimenoaikaa ja kaariaikasuhdetta. Havaittujen ongelmakohtien perusteella ryhdyttiin kehittämään hitsauskiinnittimien suunnittelua ja käsittelylaitteiden käyttöä hitsaustuotannossa sekä hyödyntämään etäohjelmointia tuotteiden viennissä robottiasemille. Lisäksi robottiasemien käyttöastetta pyrittiin nostamaan tutkimalla käsinhitsattavia tuotteita ja siirtämällä niistä robotille soveltuvimmat robottiasemille hitsattavaksi.

Political Legitimacy and Ethnocultural Justice. Essays on Public Reason, Democratic Citizenship, and the Rights of Cultural Minorities

In this thesis, I argue that there are public cultural reasons that can underpin public justifications of minority rights of indigenous and national minorities in a constitutionaldemocracy. I do so by tackling diverse issues facing a liberal theory of multiculturalism. In the first essay, I criticize Will Kymlicka’s comprehensive liberal theory of minority rights and propose a political liberal alternative. The main problem of Will Kymlicka’s theory is that it builds on the contestable liberal value of individual autonomy and thus fails to take diversity seriously. In the second essay, I elaborate on the Rawlsian political liberalism assumed here by criticizing Chandran Kukathas’s version of political liberalism as overly accommodating to diversity. In the third essay, I discuss questions of method that arise for a political liberal approach to the moral-political foundations of multiculturalism, and propose a certain understanding of the political liberal enterprise and its crucial standard of reasonableness. In the fourth essay, I dwell on the political liberal ethic of citizenship and propose a strongly inclusionist interpretation of the duty of civility. In the fifth and last essay, I introduce a certain understanding of ethnocultural justice and propose a view on certain cultural reasons as public cultural reasons. Cultural reasons are public when they are based on necessarily established cultural marks of a democratic polity, as specified by the cultural establishment view; and when they are crucial for the societal cultural bases of self-respect of citizens. The arguments in this thesis support, and help to spell out, moral-political rights of indigenous and national minorities as formulated in international legal documents, such as the Declaration on the Rights of Indigenous Peoples (United Nations 2007) or the International Covenant on Economic, Social and Cultural Rights (United Nations 1966).

Dynamic Modelling of Circulating Fluidized Bed Plant with Gas Turbine Repowering

Increasing amount of renewable energy source based electricity production has set high load control requirements for power grid balance markets. The essential grid balance between electricity consumption and generation is currently hard to achieve economically with new-generation solutions. Therefore conventional combustion power generation will be examined in this thesis as a solution to the foregoing issue. Circulating fluidized bed (CFB) technology is known to have sufficient scale to acts as a large grid balancing unit. Although the load change rate of the CFB unit is known to be moderately high, supplementary repowering solution will be evaluated in this thesis for load change maximization. The repowering heat duty is delivered to the CFB feed water preheating section by smaller gas turbine (GT) unit. Consequently, steam extraction preheating may be decreased and large amount of the gas turbine exhaust heat may be utilized in the CFB process to reach maximum plant electrical efficiency. Earlier study of the repowering has focused on the efficiency improvements and retrofitting to maximize plant electrical output. This study however presents the CFB load change improvement possibilities achieved with supplementary GT heat. The repowering study is prefaced with literature and theory review for both of the processes to maximize accuracy of the research. Both dynamic and steady-state simulations accomplished with APROS simulation tool will be used to evaluate repowering effects to the CFB unit operation. Eventually, a conceptual level analysis is completed to compare repowered plant performance to the state-of-the-art CFB performance. Based on the performed simulations, considerably good improvements to the CFB process parameters are achieved with repowering. Consequently, the results show possibilities to higher ramp rate values achieved with repowered CFB technology. This enables better plant suitability to the grid balance markets.

Hakeperävaunun aerodynamiikan parantaminen

Raskaankaluston ajoneuvojen aerodynaaminen kehitys on kulkenut väärään suuntaan jo vuosisadan verran ja niiden muodon määräävä tekijä on kuljetustilan maksimointi ja toi-minnallisuus. Lähiaikoina on astumassa EU:ssa uusi direktiivi voimaan, joka sallii lisämas-san käyttämisen aerodynaamisiin lisäosiin. Työn tarkoituksena on tutkia mahdollisuuksia parantaa hakeperävaunun aerodynamiikkaa yksinkertaisilla lisäosilla. Työ on rajattu koskemaan perävaununetuosaan, -sivuosaan ja -pohjaan. Lisäksi rajoitteita asettaa Suomenlainsäädäntö ja EU:n direktiivit. Työssä perehdytään ilmanvastusvoiman syntymekanismeihin raskaankaluston ajoneuvojen kannalta ja käydään läpi merkittävimmät vaikuttavat tekijät ilmanvastusvoimiin sekä kuorma-auton perävaunun eri muotojen ja osien vaikutus. Perävaunuun asetettavien il-manohjaimien vaikutukset ja toiminta selvitetään. Avainasemassa hakeperävaunun aerodynamiikan parantamisessa on ilmavirtauksen estä-minen perävaunun alle sekä etupuolelta. Lisäksi virtausten muuttamien perävaunun takana on hyödyllistä. Merkittävimmät hyödyt saadaan niistä ratkaisuista, jotka estävät ilman virtausta perävau-nun alle sekä renkaisiin. Näitä ratkaisuja olivat sivuhelmat ja pohjan sekä renkaiden kote-lointi. Lisäksi ilmavirtauksen estäminen perävaunun edestä tuotti merkittävää hyötyä. Levy perävaunun välissä tai koko välin peittämällä saadaan aikaan huomattavaa vähenemistä ilmanvastuksessa.