Open ecosystems, such as grasslands and pastures, have naturally been shaped by disturbances like fire and grazing. These processes play a crucial role in creating habitats with high biological diversity, particularly favourable for a wide range of herbaceous plant species. In recent years, many of these disturbances have ceased, leading to encroachment, fragmentation and habitat loss. The aim of this study was to examine and compare the effects of fire, herbivory and a combination of fire and herbivory on the emergence of herbaceous plants. The study was conducted at the Ecopark at Nordens Ark.

This thesis investigates the socio- and environmental economic effects of a deep repository for spent nuclear fuel in Forsmark in the municipality of Östhammar. I seek to show the general picture but focus on the effects on employment, environment and income. Cost-benefit analysis is used to investigate the differences in utility between a scenario with and a scenario without a deep repository in Forsmark. Most of the possible effects can not be valued and many can not even be quantified with the data available today. Therefore this thesis has a bit of a ?preliminary study character? and seeks to show what we know today and what needs to be further investigated when available data allow it. The costs that could be valued are noise from the traffic during the period of building and emissions of carbon dioxide and nitrogen oxides from the transportation of rock masses during the building period.

Highly polluted urban storm water from e.g. highways can contain large amounts of heavy metals that may cause harm if they are discharged into recipients. To remove the heavy metals a possible low-cost method that does not require much maintenance, could be the use of reactive filters with filter materials consisting of industrial residues or other cheap mineral based materials. Dissolved metal ions are removed by reactive filters through the processes of ions binding to active sites on the surface of the filter materials, or by formation of insoluble precipitates.The ability of CaO-treated granulated blast-furnace slag, iron oxide coated sand, olivine and nepheline to remove seven heavy metals (Cr, Cd, Cu, Ni, Zn, Pb and Hg) from urban storm water was studied. Initially batch experiments were performed where the effect of pH, dissolved organic carbon (DOC) and dissolved ions on the adsorption efficiency was studied.

Lotsbroverket is the largest wastewater treatment plant on the Aland Islands and it isdesigned for handling wastewater from approximately 30 000 persons. In 2011,Lotsbroverket produced about 2800 m3 of dewatered sludge. The sewage sludge that isproduced is transported to a contractor where it is processed to eventually be used e.g.in the construction of green space. This study aims to investigate available applicationoptions in terms of the sewage sludge that is produced in Lotsbroverket. The main aimis to study the feasibility of using the produced sewage sludge as a fertilizer in theagriculture of the Aland Islands.The sludge already fulfills limit values for heavy metals in accordance with the Act"The Aland Government´s directive on the use of sewage sludge in agriculture." Inorder to clarify the sludge content of pharmaceutical and organic substances it isrequired that the substances are identified and a risk assessment is performed.

Welding is a common method for joining of metal or plastic construction parts. This report describes several different weld methods in general terms. The report focuses on the GMAW method, specifically MAG welding.A case study has also been performed for the company Wenmec. The task received from the company was to compare the mechanical properties of joints welded with the tube electrode called Nittetsu SM-3A and joints welded with the homogenous electrode called ESAB Aristorod 12.63. Both types of weld joint were welded with the MAG method with an Argon based shielding gas with 18% CO2.

Det råder i dagens läge konkurrens mellan gatuträden och infrastrukturen. Människan som lever i den urbaniserade världen vill ha alla bekvämligheter inne i staden som kräver avloppsledningar, vattenledningar, gatubelysning, elledningar m.m. Samtidigt vill man ha gröna ytor i staden med stora pampiga träd. Oftast får dessa två, träden och infrastrukturen, slåss om platsen under marken och det är oftast det gröna som får lämna plats. Eftersom detta är ett återkommande problem vid de flesta nybyggnationer och nyanläggningar av ledningar, gator, parkeringar etc.

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.

Four different kinds of filter-materials with reactive surfaces have been studied concerning their capacity to absorb heavy metals in leachate from a municipal waste deposit. The heavy metals studied were: lead, cadmium, copper, mercury, chromium, nickel and zinc. The leachate contains high levels of dissolved organic carbon (DOC) and has a high pH-value along with a high buffer capacity. These characteristics of the leachate make it difficult to remove pollutants and require efficient filters. The filters that were examined in the report are blast-furnace slag with CaO, sand covered with iron oxides, olivine and nepheline.

During 2006 SNVDB (the national road data base for forestry) is being introduced to Holmen Skog. This data base contains all information about Holmen Skogs road systems. The information will then be used in different kinds of optimisation models which only produce correct and reliable results if the input data are of the adequate quality. Today there are reasons to believe that road data is of various qualities. The forest roads are often in a bad condition and have to be improved before a planned harvest. The cost of maintenance and construction of new roads is a large part of the total harvesting cost.

The eutrophication of lakes and seas with the algal bloom and deficiency inoxygen that follow, has been given priority by the Swedish government as oneof 16 environmental objectives. The purpose of this project was to develop a toolbased on a simple model, limited amount of data and geographic informationsystem (GIS) to identify areas with risk for phosphorus losses due to surfacerunoff. This tool can act as a decision support to decide where appropriatemeasures should be applied with the aim of reducing phosphorus losses and bythat the eutrophication.The method that has been used is a combination of two models, one calculatingthe potential erosion while the other one identifies areas of erosion (net erosion)or deposition. This ability is of great importance because potential erosionshould be calculated on areas with net erosion. Areas with high potential erosionhave an increased risk for phosphorus losses due to surface runoff.The potential erosion was calculated based on factors which describe how topography(LS), land use (C), soil type (K) and precipitation (R) effect the erosion.All of them have been modified to a greater or lesser extent.

It has been observed by both onion producers and a plant protection advisor on Öland (an island off the east coast of Sweden) that basal rot is the largest contributory factor to reduced onion quality and yield. Basal rot is mainly caused by species of Fusarium fungi. The aim of this study was to: a) investigate which species of Fusarium that can be found in onion produced on Öland, b) describe the symptoms caused by the different Fusarium fungi found and c) explore, through interviews with the onion producers on Öland, the mechanisms that may be involved in the observed increase in basal rot.Onion bulbs (Allium cepa) were sampled on two occasions. In total 181 onions from 11 different fields were analysed. In addition, eight onion producers were interviewed.

When protection zones for wells are delineated, it is important to acquire good knowledge about possible travel time from different points in the catchment area to the well. Often, simple analytical methods are used for estimating travel times and the assumption is made that the hydraulic conductivity is relatively homogenous within the aquifer. Nevertheless, many aquifers are strongly heterogeneous which may lead to differences between estimates and actual travel times. As a part of the process to develop improved methods for delineating protection zones for groundwater supply wells, a tracer experiment was performed in a glaciofluvial esker formation in Järlåsa. On the basis of the experiment, a numerical flow model was created for the test site.The purpose of this master?s thesis was to apply the flow model to an aquifer where the hydraulic conductivity shows great variability and should be described by a stochastic distribution.

X-ray fluorescence (XRF) detection of heavy metals is a cost- and time-effective method for investigation of polluted areas. Compared to laboratory analysis, XRF analysis is limited by high detection limits and uncertainties in some situations. Preparation of samples is known to affect the results of measurements.The purpose of this thesis is to bring a deeper understanding of how different factors affect the results of XRF-analysis. A large number of measurements have been made with the instruments Niton XLt 700 and Niton Xli 700. Results from measurements of lead, zinc and copper have been analysed.This study has shown that a greater moisture content will give a lower measured concentration for the same sample.

After the last is age there was a long period when there was no shortage of forest for peoples needs. People living in Sweden could use the forest resources at their will. Around 4000 years BC the inhabitants of southern Sweden started to use the agricultural system and people become more stationary. The farms were located together in groups and together they formed a social association, the village. Successively the population grew and in some areas the forest started to become a finite resource.

BAE Systems Hägglunds has a long history of producing high performance terrain tracked vehicles (mostly for military applications), and they are now aiming at developing a tracked forwarder with similar techniques.The forwarder will be of series hybrid type where a diesel engine via a generator will power the motors (one for each drive wheel). Thanks to individually controlled motors and the gentle rubber tracks, this forwarder is calculated to have a considerably higher average speed in the terrain and to be more gentle to the soil. The forwarder with a weight of 11 metric tons and a load capacity of 15 metric tons is specified to have an average working speed of 7-10 km/h, a top speed in terrain of 15 km/h and a top speed on roads of 40 km/h.This master?s thesis aims at developing a conceptual design of the forwarder?s drive module which includes electric motor, gear unit, brake and drive wheel.To investigate if the requirements can be fulfilled a study of the dimensioning loading scenarios has been carried out. The resulting needs regarding the torque has been considered in order to determine the required gear ratios for different motor options.