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8597 Uppsatser om Power quality problems - Sida 64 av 574
Utvärdering av konsekvenserna för nätanslutning av vindkraftparker i Sverige vid införandet av nätkoden Requirements for Generators
Grid codes are becoming more demanding on power generating units due to the factthat the complexity of the power grid is increasing. The penetration of wind powerhas grown over the last years and it is clear that wind farms need to be addressedwith the same type of grid codes as conventional generation units. There is howeveran undeniable difference between the technology in conventional synchronousgeneration units, and the asynchronous generation units in wind farms.This thesis has reviewed the current grid code in Sweden and compared it to the newcode proposed by ENTSO-E, ?the Requirements for Generators?, in the aspect ofwind farms with an installed power of 30 MW or more. The comparison has beencomplemented by an analysis of how wind farms of two different technologies(Doubly fed induction generators and full power converters) can meet therequirements and technical proposals have been given on how to be able to meetcompliance with the new grid codes.The Requirements for Generators contains many non-exhaustive and optionalrequirements, because of this it has been difficult to, at this stage, exactly point outthe technical impact on the grid connection of future wind farms in Sweden.
Rapportering om förortsproblematik i media : - Ett uttryck för stigmatiserande strukturell diskriminering eller en arena för möjlighetsorienterade politiska lösningar?
This thesis aims to examine the nature of the medial compartment regarding the reporting of problems in conjunction with suburbs. Previous research on discrimination in the media shows that people living in the suburbs considers suburbs being portrayed negatively in the media. They perceive that this has a negative effect on integration which in turn increases the risk of stigmatization. This study strives to contribute to the clarification of whether medias means of reporting around this area can help in the development of problems in suburbs by examining whether there is a reflection of actual political focus in the media or if media only plays a stigmatizing role. The research method used has been quantitative content analysis, making an overview of how much space is given to the different types of reporting. The thesis concludes that the reporting examined in this study did not appear to be of a structurally discriminatory nature, even if that type of reporting occurred.
Epiphytic lichens associated with different traffic intensities along the highway E4
Inventories of epiphytic lichens on Scots pine (Pinus sylvestris) were conducted at three sites in east central Sweden: along the newly build motorway (Road E4), along the old road (Road 600) and in a reference site, to compare the effects of traffic pollution on lichen diversities. At each site, species richness, lichen mean sensitivity value (MK), air quality index of the forest stand/sample plot (LKI) and nitrogen impact value (N) were calculated and it was tested if there was any difference between the sites. Twenty-four species were observed in total, and Parmeliopsis ambigua and Hypogymnia physodes were the most common species at all sites. At Road E4, fewer lichen species were observed than at the other sites and this might be due to the impact of air pollution. The species richness at Road 600 was similar to that of the reference site, which might be explained by the improved air quality.
Bors E23 - Framtagning av eldriven röravklippningsmaskin
Our Bachelor´s Thesis has been performed in co-operation with Bors Automation & Tool AB.Our task was to develop a servomotor powered tube cutting-machine with initial point fromtoday's hydraulic driven tube cutting machine Bors HYD 23. The purpose with the newconstruction was to achieve a more power-efficient tube cutting machine which could lowerthe power consumption, and also meet the market continued growing demand forenvironmental-conscious production.Bors Automation & Tool gave us relatively free hands in order to enable new thinking ideaswithout following their traditional constructional solutions.Our solution resulted in a construction based on a power source existing of a servomotordrivenrollerscrew, witch provides a more rational use of energy compared with the currentmethod.Bors Automation & Tool AB has decided to fabricate a prototype of Bors E 23 during theautumn of 2007, which they are planning to revile at the Tube 2008 exhibition in Düsseldorf,Germany.NOTE:Due to an agreement signed by the authors in the beginning of this project, no appendix is published at this time.If you want to wiew these documents, please contact the authors..
Interaktionens pris : Mot en ny konstkritik
The paper discusses the problems contemporary Swedish art criticism faces when judging performance art and interactive art. Problems include among others that performance art is collectively ignored in Swedish newspaper art criticism. This prevents art critics from fair contextualising of contemporary performance art. Down in the rabbit hole, performance by Tris Vonna-Michell and its reception exemplifies these problems. Performance and interactive art seems to be disturbing art critics.
Cancersjuka patienters upplevelse av livskvalitet och välbefinnande i samband med yogautövning. : En deskriptiv kvalitativ studie med semistrukturerade intervjuer.
AbstractAim: The aim of this study was to describe cancer patients? experiences of quality of life and wellbeing in relation to yoga practice.Method: A descriptive qualitative study with semi structured interviews was carried out during the fall of 2009 at the University of Uppsala. Informants in the study were cancer patients who were participating in the yoga/psychotherapy group at the clinic of oncology at the Akademiska hospital in Uppsala.Result: Five out of six informants experienced that their quality of life and their wellbeing improved by practicing yoga. One informant had mixed feelings which were not due to the yoga practicing, but to the place where it was practiced. For her this place was associated with illness.
Tidssynkroniserade mätningar i vattenkraftstationer
Vattenfall and Svenska Kraftnät perform start-up tests, where hydropower generators are used to power up the electrical grid in case of a blackout. To monitor the electrical grid, Phasor Measurement Units (PMU) are used. Each PMU is individually equipped with a GPS-receiver to precisely timestamp the data relative to the official time UTC. During the test, it is also of interest to timestamp the measurement signals from individual hydropower generators to later compare with PMU-data, and thus study the power grids impact on the generator. The aim is to work out an appropriate method to make these measurements and to build a data acquisition system, capable of timestamp data relative to UTC, from a generator in one of Vattenfalls hydroelectric power stations. The problem is that the generator is located in an underground station which hampers the reception of GPS-signals and wiring should be avoided if possible. Time synchronization has been solved by using Vattenfalls network, which is synchronized by the network protocol NTP.
Vad det nu hette...Jämställdhet...? : Ett utredningsarbete på en klinik
The aim of this investigation work " What was it called...Equality...? is to study a clinics current gender equailty plan from a gender approach and by a field survey see if, and in that case, how it can be improved. A connection between existing gender norms and gender power strukctures is applied in the results of this survey in order to illustrate their significance from an individual as well as a structural perspektive.The survey has been carried through by a field survey as well as a discourse analysis as method. Yvonne Hirdmans gender power system is on of the main theoretical points of departure.The results that I have achieved in this essay is that gender can be looked at in different ways within the labour market where women have the main responsibility over the family and are considered more nursing then men. Men on the other hand are thinking of their carriers and have higher salary requirements.
Lämpliga främmande trädslag för Kalmar och Mönsterås kommuner
This report concerns the for Sweden foreign tree species hybrid larch, hybrid aspen and poplar, and focuses on the area Kalmar and Mönsterås municipalities. The report shows that there are not only advantages with these species. The larch, the most common of the alien tree species has the greatest problems due to that its timber is difficult to sell in the area but also the Larch´s poor pulp quality and is more likely to be damaged by wildlife than the spruce is. Hybrid Aspen is much easier to sell and is used like regular aspen for match wood and textile pulp. Its disadvantage is the high cost for plants and to prevent damage from wildlife.
Miljöutredning av gaturenhållningen, park- och naturförvaltningen i Göteborgs Stad
The ability to tackle NP-hard problems has been greatly extended by the introduction of Metaheuristics (see Blum & Roli (2003)) for a summary of most Metaheuristics, general problem-independent optimisation algorithms extending the hill-climbing local search approach to escape local minima. One of these algorithms is Iterated Local Search (ILS) (Lourenco et al., 2002; Stützle, 1999a, p. 25ff), a recent easy to implement but powerful algorithm with results comparable or superior to other state-of-the-art methods for many combinatorial optimisation problems, among them the Traveling Salesman (TSP) and Quadratic Assignment Problem (QAP). ILS iteratively samples local minima by modifying the current local minimum and restartinga local search porcedure on this modified solution. This thesis will show how ILS can be implemented for MSA.
Strukturerat arbete vid verksamhetsplanering och mjukvaruuttveckling : en studie på Volvo IT i Trollhättan
The ability to tackle NP-hard problems has been greatly extended by the introduction of Metaheuristics (see Blum & Roli (2003)) for a summary of most Metaheuristics, general problem-independent optimisation algorithms extending the hill-climbing local search approach to escape local minima. One of these algorithms is Iterated Local Search (ILS) (Lourenco et al., 2002; Stützle, 1999a, p. 25ff), a recent easy to implement but powerful algorithm with results comparable or superior to other state-of-the-art methods for many combinatorial optimisation problems, among them the Traveling Salesman (TSP) and Quadratic Assignment Problem (QAP). ILS iteratively samples local minima by modifying the current local minimum and restartinga local search porcedure on this modified solution. This thesis will show how ILS can be implemented for MSA.
Studentens användning av elektronisk handel och dess tjänster
The ability to tackle NP-hard problems has been greatly extended by the introduction of Metaheuristics (see Blum & Roli (2003)) for a summary of most Metaheuristics, general problem-independent optimisation algorithms extending the hill-climbing local search approach to escape local minima. One of these algorithms is Iterated Local Search (ILS) (Lourenco et al., 2002; Stützle, 1999a, p. 25ff), a recent easy to implement but powerful algorithm with results comparable or superior to other state-of-the-art methods for many combinatorial optimisation problems, among them the Traveling Salesman (TSP) and Quadratic Assignment Problem (QAP). ILS iteratively samples local minima by modifying the current local minimum and restartinga local search porcedure on this modified solution. This thesis will show how ILS can be implemented for MSA.
Förslag till nytt energimätningssystem på Volvo Aero Corporation i Trollhättan
The ability to tackle NP-hard problems has been greatly extended by the introduction of Metaheuristics (see Blum & Roli (2003)) for a summary of most Metaheuristics, general problem-independent optimisation algorithms extending the hill-climbing local search approach to escape local minima. One of these algorithms is Iterated Local Search (ILS) (Lourenco et al., 2002; Stützle, 1999a, p. 25ff), a recent easy to implement but powerful algorithm with results comparable or superior to other state-of-the-art methods for many combinatorial optimisation problems, among them the Traveling Salesman (TSP) and Quadratic Assignment Problem (QAP). ILS iteratively samples local minima by modifying the current local minimum and restartinga local search porcedure on this modified solution. This thesis will show how ILS can be implemented for MSA.
Förbättring av tillgänglighet robotcell för diskmaskinsbehållare samt cylinder-behållarline tvättmaskinscylindrar och behållare
The ability to tackle NP-hard problems has been greatly extended by the introduction of Metaheuristics (see Blum & Roli (2003)) for a summary of most Metaheuristics, general problem-independent optimisation algorithms extending the hill-climbing local search approach to escape local minima. One of these algorithms is Iterated Local Search (ILS) (Lourenco et al., 2002; Stützle, 1999a, p. 25ff), a recent easy to implement but powerful algorithm with results comparable or superior to other state-of-the-art methods for many combinatorial optimisation problems, among them the Traveling Salesman (TSP) and Quadratic Assignment Problem (QAP). ILS iteratively samples local minima by modifying the current local minimum and restartinga local search porcedure on this modified solution. This thesis will show how ILS can be implemented for MSA.
Utveckling av en provmetod för ett CAN-baserat nätverk
The ability to tackle NP-hard problems has been greatly extended by the introduction of Metaheuristics (see Blum & Roli (2003)) for a summary of most Metaheuristics, general problem-independent optimisation algorithms extending the hill-climbing local search approach to escape local minima. One of these algorithms is Iterated Local Search (ILS) (Lourenco et al., 2002; Stützle, 1999a, p. 25ff), a recent easy to implement but powerful algorithm with results comparable or superior to other state-of-the-art methods for many combinatorial optimisation problems, among them the Traveling Salesman (TSP) and Quadratic Assignment Problem (QAP). ILS iteratively samples local minima by modifying the current local minimum and restartinga local search porcedure on this modified solution. This thesis will show how ILS can be implemented for MSA.