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367 Uppsatser om Wind erosion - Sida 3 av 25
Fotogrammetrisk analys av kornstorleksfördelningeni erosionsskydd vid kraftverksdammar
This master thesis was made to investigate the possibilities of using the Matlab-basedsoftware Basegrain to determine grain size distributions of erosion protections onhydropower dams. Basegrain is a photogrammetric tool developed to generate grainsize distributions and other information about coarse flood sediments by analyzing adigital photo of the stone bed. The investigation was made by validating the ability forBasegrain to assess grain size distributions of various materials smaller than the blocksused in an erosion protection by comparing sieving results or manual measurementswith the results obtained by the program. A statistical comparison was then made bycomparing the results from sieving and the program. The possibilities of using thesame method on existing hydropower dams were then investigated by determiningwhether the method was practically viable or not.The results showed that Basegrain generated grain size distributions for coarse gravelthat were very close to the sieving results.
Stranderosion i Skåne
Erosion är en ständigt pågående process som formar om vårt landskap. Längs med kusten pågår ett samspel mellan vind, vågor, strömmar och sediment. Ett område kan sägas vara utsatt för erosion om mängden borttransporterat material är större än den mängd som avsätts. Det omvända kan också inträffa, det vill säga att stränder växer. Detta kallas för ackumulation.
En vindkraftparks inverkan på Gävle Energis elnät
The effects from a planned wind farm on the grid utility Gävle Energis electrical grid have been studied. The wind farm is planned to be built in the forest 15 km north of Gävle and will have 23 turbines with rated power from 2 to 2.5 MW, resulting in a total installed power between 46 MW and 57.5 MW. The grid connection will be made at 70 kV. The aim of the analysis was to determine what effects the wind farm would have on the power grid in the form of electrical disturbances (flicker etc.), need for new investment and raised operational cost. To allow the connection of the wind farm technical solutions (new lines, power stations and grid reinforcements) have been constructed.
Vindkraftens påverkan på sin omgivning : En fallstudie
Purpose of this thesis is to study the impact of wind turbines on their surroundings. It also aims to analyze how the communication looks between the authorities, the planner and local residents prior to the establishment of wind turbines in Lännäs/Odensbacken in Örebro, where three wind turbines set up in a group.The results of this survey show that the participants experience themselves not as especially disturbed of the turbines in the form of large noise, shadows, and sleep disturbance indoors and outdoors. Participants felt that no change had taken place on the natural environment (52%) since the turbines became operational. It was 49% of participants had got no information about the establishment of Örebro Municipality, Örebro County Administrative Board or Wind Power Company. Scientists/experts had the highest confidence of 86%, politicians and the media/journalists had least confidence.
Simulering av elektriska förluster i en vindkraftpark : Utveckling av programvaran Wind Farm ElectricSystem Calculator (WFESC)
When planning new wind farms, the cost for the internal electrical grid is estimated to account for 8-9 % of the total investment cost. On top of that, the cost for accumulated reduced income over several years (due to electrical losses), has to be added. The economic lifespan is relatively long (about 20 years) which means that an error in the loss calculation could lead to a bad decision basis. The accumulated reduced incomes due to electrical losses can be higher than the initial investment cost for the internal electrical grid.Today, Statkraft Sweden is using a template number when estimating the electrical losses in a wind farm. The actual losses are probably lower than the template number which could lead to an unnecessary high loss cost when planning a new wind farm.The aim of this M.Sc.
Vindkraftens framtida scenarier
In several countries that have been early in the development of wind farms, there is today a second hand market for the used wind turbines. The European Union (EU) has established a waste hierarchy in order to minimize throwaway mentality. The second hand market is a part of this as the steps are to minimize, reuse, recycle, extract energy and landfill.In order to promote the development of renewable energy, there are energy certificates for the producers that provide it, wind power being one type of renewable energy. After 15 years the energy certificates for a specific wind turbine are no longer paid, and after that there are several different scenarios for the wind turbine. The scenarios investigated in this bachelor?s thesis are export of the wind turbine to countries that are not as far along as Sweden in their development towards renewable energy, selling in Sweden to individuals, and recycling of the wind turbine, as it mostly consists of metals and therefore is recyclable.
Kunskap om dental erosion hos en grupp fotbollsspelare
Introduktion: Erosionsskador är ett växande problem bland barn, ungdomar och unga vuxna. Dental erosion har en multifaktoriell etiologi som består av endogena och exogena orsaker. Att erosionsskador på tänderna ökar kan bero på den höga konsumtionen av sura drycker bland barn, ungdomar och unga vuxna. Personer som idrottar kan löpa risk för dental erosion på grund av frekvent intag av sura sport/energidrycker men även till följd av påverkat salivflöde. Få studier har undersökt fotbollsspelares kunskap om dental erosion och dess konsumtion av sport/energidryck.Syfte: Att studera kunskapen om erosionsskador bland en grupp fotbollsspelande kvinnor och män.Frågeställningar: Vilken kunskap har fotbollsspelande kvinnor om erosionsskador? Vilken kunskap har fotbollsspelande män om erosionsskador? Vilken konsumtion har fotbollsspelarna av energi/sportdryck?Metod: Studien är en kvantitativ, empirisk, tvärsnittsstudie.Resultat: Totalt deltog 44 personer i studien, 29 kvinnor och 15 män.
Urban vindkraft : Vindkraftsprojekt Järvafältet & vindkraft i Sverige
Wind power is an energy source that is becoming increasingly popular in Sweden and around the world. The establishment of large wind farms supply and contributes to energy production within grid in search of a more sustainable energy production. Wind power is becoming more popular and opens up new areas of implementation. More cities are starting to use small-scale urban wind power, everything from full-scale work for a little less work adapted to the villas. Sweden has high goals regarding the production of green electricity and the work which deals with the conditions Sweden plays in achieving those goals.
Accessoarer för framtidens kontor
This thesis investigates if a system for small scale electricity production located in anurban environment can be profitable. The work has been divided up into two parts,one extensive literature study and one case study. The purpose of the literature studywas to investigate the area, resulting in a choice of which technology to be studied indepth in a case study.In the case study a system containing small scale wind turbines and photovoltaicsmounted on Gränby Centrums roof was examined. From data containing wind power,wind direction and total irradiation, possible production from a system weresimulated. Three products of each technology were examined in the simulations.From the simulated production an economic analysis was carried out, this toinvestigate if a system is profitable.
Strömningen i och över en skog : utvärdering av en 'mixing-layer' hypotes
A new theory for predicting the windprofile over a canopy has been evaluated. The theory was first presented by Harman and Finnigan (2007). The theory relies on the forming of a mixing-layer above the canopy, due to different mean wind in and above the canopy. Characteristics from both mixing-layer and Monin Obukhov similarity theory have been used to develop the governingequations that give the wind profile. The theory has been used to calculate wind profiles for sixdifferent atmospheric stabilities.
Skydd mot yterosion i slänter av finmorän
Slopes in fine till soils are exposed to surface erosion due to rainfall, snowmelt and upland water sources. Large areas of road slopes are therefore covered for surface erosion protection. Preventive methods like ditches and trenches are also being used. Silt tills are particularly troublesome since the water can bring the soil into suspension and cause mudslides. Different methods for erosion protection have been studied in this work, with the emphasis placed on rockfill covering. The need for and the dimensioning of this type of covering has been examined in literature and field studies.
Utvärdering av svensk vindkraft : Skillnaden mellan skogs- och traditionella placeringar
During the last years commercial Wind Power Turbines (WPT) has become larger regardingto the generator sizes and hub heights. Available hub heights around 100 meters is nowcommon, which has led to profitability for WPT located in forests where there normally are tolow wind speeds. The current knowledgement regarding turbulence and the variation in thewind profile for the outcome of the power production for the WPT in forests is limited.In this Master of Science thesis an investigation concerning forest located wind power plantshas been made. The purpose has been to investigate if plants located in forest perform lesscompared to wind power turbines located at more common locations.The analyses are based on statically material for determining the availability,production/generator size, production/hub height, production/swept area and how thetopography affect the production results.The analyses show that the variation in production result for WPT located in forest comparedto turbines located at other locations is small. The availability is high and the productionresults are good..
Privata markägares syn på vindskadeförebyggande åtgärder :
Wind and wind damage has become a hot subject because of the storm ?Gudrun? in January 2005. The main purpose of this study was to establish how the land owners attitude toward preventive wind damage actions was changing immediately after they had been struck by a storm.
The result of the study was built on interviews. In springtime 2005 a total number of 20 private land owners were interviewed. Ten of the landowners lived in the province of Småland and ten in the province of Värmland.
Stormskador i lärk och gran : en jämförelse efter stormen Gudrun
The storm Gudrun January 8-9 2005 felled about 70 millions cubic metres forest in southern Sweden. The majority of the wind damaged forest was spruce (Picea abies). In order to decrease the risk of wind damages in the future other trees species are of interest for forestry in southern Sweden.
The purpose of this master thesis was to study if larch were more wind tolerant than spruce. The method was to compare larch, Japanese larch (Larix kaempferi Lamb.), European larch (L.
Småskalig elproduktion i urban miljö : Fallstudie av elproducerande system på ett handelscentrum
This thesis investigates if a system for small scale electricity production located in anurban environment can be profitable. The work has been divided up into two parts,one extensive literature study and one case study. The purpose of the literature studywas to investigate the area, resulting in a choice of which technology to be studied indepth in a case study.In the case study a system containing small scale wind turbines and photovoltaicsmounted on Gränby Centrums roof was examined. From data containing wind power,wind direction and total irradiation, possible production from a system weresimulated. Three products of each technology were examined in the simulations.From the simulated production an economic analysis was carried out, this toinvestigate if a system is profitable.