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296 Uppsatser om Wind speeds - Sida 18 av 20

Site preparation, planting position and planting stock effects on long-term survival, growth and stem form properties of Pinus contorta on southern Iceland

In order to evaluate different afforestation methods for exposed heath lands a field experiment was established in Mosfell on southern Iceland in 1989. The trial comprised six different site preparation methods (control, herbicide application, tree shelters, patch scarification, TTS trenching and mounding). In total 960 container seedlings (1+0) and 960 Nisula roll transplants (2+1) of lodgepole pine were planted. Various planting positions (furrow, hinge, no site preparation (control) and on top of mounds) were tested within the site preparation treatments. This study involves renewed measurements and analyses of the trial.After 19 years the overall survival was 51,7 %.

Dammet, vår minsta gemensamma nämnare : En känsla av tillhörighet

Dust, our smallest common denominator                                                                                                                                                                 Charlotta Lindvall ABSTRACT  I find it fascinating to know that we are all made of the same material as the stars and that everything is connected to each other and in a constant movement and transformation, a recycle of material. We are all made of stardust. In fact all life is sprung out of dust.In my essay I investigate the dust and ask the question if there are any traces in the dust. I look at the history of the dust and how it has affected us and our world through the decades. What does this small and airy but oh so unappreciated dust tell us? Why do we want to get rid of it? Is it possible to find a sense of belonging in the big context by investigating the dust and its origin and could I transform such a low material as dust into something magic that makes people reflect on our origin and belonging and how everything is connected? In my work I use dust as a material and in the essay I compare my work with other artists who have worked with dust as a material.Dust is everywhere because its source is from everything.

Resultat av tjugofem års mätningar av Cs-137-halter i älg i Uppsala län

At the end of April 1986 reactor number 4 of the nuclear power plant at Chernobyl explod-ed and large amounts of radioactive particles were then released into the atmosphere due to both the explosion as well as the consecutive fire of the graphite core. A cloud of radioac-tivity was spread over the northern hemisphere, including Sweden, due to the prevailing wind directions. The radioactive particles were washed out from the cloud by rain and snowfall in some areas of Sweden and deposited on the ground. The deposited radionu-clides, primarily cesium and iodine isotopes, were later absorbed into the soil and taken up by the roots of the plants. Some of these radionuclides, like 137Cs, still persist in some of the terrestrial ecosystems at relatively high concentrations which lead to contamination of the meat of moose, roe deer and wild boar even today.The two municipalities Heby and Uppsala, in the eastern part of central Sweden, experi-enced a relatively large deposition of 137Cs which resulted in high levels of 137Cs in moose and other game.

Utvärdering av statistiska analysmetoder för detektion av partiell nedisning av anemometrar

Detaljerad information om vindförhållandena på en site är en nödvändighet för att göra beräkningar av lönsamhet i ett vindkraftsprojekt. Mätningarna behöver vara kontinuerliga och så korrekta som möjligt. Därtill bör de göras under minst ett års tid eftersom vindförhållandena på en plats är säsongsberoende. Under vintertid och framför allt på högre latituder eller altituder, kan mätutrustning påverkas av nedisning. En nedisad anemometer kan ge databortfall eller felaktiga mätningar.Identifiering av felaktiga data är en viktig del av analyseringsarbetet eftersom risken annars är att vindförhållandena på platsen underskattas.

Vindkraft i motvind : En studie om kommunikation kring ett vindkraftprojekt

Etableringen av en vindkraftspark är sällan okontroversiell och involverar en stor mängd intressenter i form av företag, myndigheter, föreningar och privatpersoner. I den här Cuppsatsen studeras ett planerat vindkraftsprojekt på Mästermyr utanför Hemse på Gotland. Mästermyrprojektet är ett tydligt exempel på en lång och utdragen planeringsprocess som i slutändan ledde fram till att byggtillståndet överklagades och att projektet lades ner. Kommunikation i vindkraftsprojekt har i rapporten Wind energy and local acceptance: Howto get beyond the Nimby effect identifierats som ett effektivt vapen mot NIMBY-effekten. NIMBY står för ?not in my backyard? och med detta menas att människor och organisationer ogärna vill ha vindkraftverk i sin närhet även om de över lag är för vindkraft.Uppsatsens syfte är således att studera kommunikationen i Mästermyrsprojektet för att svara på vad i processen som leder fram till att byggtillståndet överklagas samt vilka möjligheter att påverka utbyggnadsplanen som intressenter har haft.

Utredning av frekvensregleringens påverkan på mekanisk utrustning i en kaplanturbin

As a consequence of increasing wind power installations in the Nordic grid the last years, the need for regulating power has become larger. In the Nordic grid, regulating power is mainly provided by hydro power. One part of the regulating power is called frequency control, which ensures that the grid frequency is stable and close to 50 Hz.However, setting the turbine into frequency controlled operation may cause stress and wear of the components in the mechanical control system. Frequency controlling implies large and frequent servo forces and longer travelling distance of the sliding bearings in the Kaplan turbine.Based on one selected Kaplan turbine, Selsfors G1, measurements and MATLAB calculations have been performed in order to determine forces and movements of the linkage system. With these forces and movements as input, stresses and fatigue have been determined as well as sliding distances, bearing pressures and wear of bearings during a typical lifetime of 40 years.The results indicate that no severe wear exists on the bearings during 40 years of service.

Timeliness cost for agricultural sprayers : weed control in cereal crops

Evaluation of machinery costs is necessary for selecting appropriate farm machinery. Timeliness cost due to untimely operations is an important component of machinery costs. Timeliness costs can be high for crop sprayers, since pesticide application must be carried out within a short time interval. This Master thesis investigated the timeliness cost and the probability of a suitable workday for spraying. Timeliness factors were estimated for four different crops (oats, spring wheat, winter wheat and barley) using historical weed trial data.

Optimal välfärd och hälsa för kalvar :

In order to optimize calf welfare and health it is important to know the behavior of cattle in free ranging conditions. When the cow is about to give birth to a calf she will leave the heard about 12 hours before. It is then rather obvious that isolating the cow about calving time in a single pen is imitating the cows? natural behavior. To save space and minimize building cost it?s common that the farmers build calving pens for four of five cows especially at larger farms.

Hästinventering i Degerfors kommun

Animal welfare in Sweden has gone through major changes during the later years. In 2004, Swedish Animal Welfare Agency took over the central responsibility for the animal welfare from the Swedish Board of Agriculture, and in 2007 the board again became the central authority for animal welfare in Sweden.Even the practical supervision has changed, from the 1 of January 2009 the supervision is to be performed by the county administrative boards, instead of by the individual municipalities. Since 2006 every horse in the European Union has to have an identification card, in Sweden called a ?horse passport? which describes the color and markings of the horse as well as any veterinary treatments.The ELOF-project, a collaborative project between the Swedish Board of Agriculture and the county administrative boards, intends to make the animal welfare supervision effective, standardised, fair and risk-based. Because of the takeover of the supervision and of the ELOF-project the Örebro County Administrative Board has began to make an inventory of the number of horses and horsefarms in the county. Another Ethology and Animal Welfare-student and I did, in collaboration with the county administrative board created a checklist that in connection with the inventory will lead to a risk-based animal welfare supervision.

Smarta lokala energisystem, Vision-Teknik-Tillämpning

The energy sector is facing an impending paradigm shift. Today?s technology enables the end-user to generate their own energy locally at home. Furthermore, recently developed storage technologies make it possible to balance energy demand with stored energy and integrate district heating with the local power grid. This means that in the future heat and electric power will interact and energy flows is converted over energy boundaries.

Det blåser kring vindkraft! : En kontroversstudie om vindkraftsetablering på Västkusten

Vårt syfte med denna studie är att undersöka de kontroverser som uppstått vid vindkraftsetableringar på Västkusten. Detta syfte innefattar frågeställningar om vilka argument och aktörer som är inblandade och vad som formar en aktörs åsikter.Anledningen till att vi valde detta område var på grund av ett förslag vi fick från en konsult inom området. När vi studerat ämnet närmare insåg vi att det existerar kontroverser kring de olika etableringar som skett och även runt de som endast är i planeringsstadiet. Dessutom insåg vi att det inte fanns mycket aktuell forskning inom området.Studien är baserad på material som har insamlats i form av samrådsredogörelser, artiklar, insändare och fyra utförda intervjuer. Tolkning av materialet har skett utifrån en diskursanalys som gett resultat i form av tre olika diskurser inom kontroversen; Miljödiskursen, Lekmannadiskursen och den Ekonomiska diskursen.

Modellering och styrning av flis till en sulfatkokare

At the Skoghall pappermill, sulphatepaper pulp is produced in a continuous digester originally from 1969. To be able to maintain a high level of production there is a need for a process with few disturbances. Variations in how well the wooden chips are packed in the digester is one form of disturbance. Today there are no available measurements on how well the chips are packed. Instead this is regarded as being constant.

Sorterar skotaren bort det timmer som skördaren har tillrett? :

The efficiency of the harvesters work is more often reviewed, than the work of the forwarders. In a local Stora Enso office the differences between the harvesters reported volume of timber, and the actual volume delivered to the industry had been noticed. Therefore, the decision was made to do a review on the forwarders work. The review was conducted together with a worker from Vmf Qbera, who is working daily with wood measurement, in order to get a valid evaluation of the logs. Eight sites were included in the survey, and on each site 50 logs were marked. Approximately one third of the marked logs were pulpwood, and the remaining logs marked were timber.

En jämförelse av energiåtgång och emissioner för olika persontransportslösningar i Stockholm stad

This master thesis sets out to compare the different public transport modes in Stockholm city.Both energy consumption and air pollution are compared. The chosen transport methods are car,bus and metro.Traditionally the rail industry has had environmental arguments as a strong competitiveadvantage when it comes to passenger transportation. However, in recent years the automotiveindustry has been getting more positive media attention regarding environmental issues, forexample Roger Kemp?s statement that the car is the most environmental friendly passengertransportation mode in the UK. This study will show the environmental advantages of railwaytraffic in cities.The energy sources of the world are not endless and the use of the different sources affects theenvironment in different ways.

Trädens utveckling efter att de har lämnats som naturhänsyn : tillväxt, mortalitet och strukturell förändring 6-18 år efter avverkning

Today green tree retention, together with leaving dead wood, is a common practice with the aim to reduce negative impacts on biodiversity and environment due to clear-felling. To better understand whether this conservation practice also makes a long-term difference, it is important to know what happens to these trees after harvest. Few studies have made an assessment of what happens to retention trees over a longer time period. In this study I inventoried retention trees that were left at clear-cuts six, twelve and eighteen years ago. I carried out a re-inventory of 57 retention patches (divided into free-standing tree groups, small swamp forests and edge zones) and free standing dead trees, spread over 25 previous clear-cuts in central Sweden.

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