This report is a study in voltagelevel in connection with regeneration of brake energy from the tramtype M31 in Gothenburg.In the act of braking, the tram M31 uses electrical braking where the electrical motors generates energy and if possible send it back to the overheadline, where other trams in the nearby can use this regenerated energy for its own driving force. In cases where no other energyconsumers are located in the same section, there is a resistance witch task is to convert this energy into heat. The regulation of this resistance appears to cause an increase in the voltagelevel into far too high levels.Investigations of the trams regulationequipment and its construction have been done. Further have measurements on the overheadline been performed in order to map the voltagevariations during a longer period of time.The result have been showing that the voltagelevel during regeneration often is as high as 880V-920V, more extreme values have not been observed in a large scale. The values are especially high compared to the nominal voltagelevel.

Turning solar collectors, heliostats, is certainly not a new idea but has been explored for at least two decades. Projects on this subject have resulted in more or less realistic constructions, in a commercial point of view. Far too often the technical goals have had higher priority than the economical, which has resulted in a few constructions having the ability to compete with conventional, fix solar collectors. The economical issues have been given high priority in this project, without decreasing the demands on reliability. The system has been given the following mechanical and electronical properties: One-axis movement, fix heat carrying fluid system, microcomputer controlled movement and automatic protection from overheating.

Today when new and harder demands on CO2 emissions are developed, vehicle manufacturers must work to develop new engine solutions to new kinds of fuels to replace fossil fuels. A fuel that could be applied is hydrogen. When hydrogen is combusted only water vapor occurs. Hydrogen is known to be explosive and flammable. These properties are both good and bad for combustion.

Estimation of the variation in the integrated hydraulic conductivity around the Tunåsen infiltration facility - An investigation of the effects of uncertainties in existing informationAlmost half of Sweden?s drinking water volume is produced from groundwater. The main fraction of this is extracted from eskers, some of which allow for very large extraction rates. Despite this, the groundwater volume is not sufficient in some areas. This has led to an extensive use of artificial recharge.In Uppsala, the total volume added through artificial recharge is divided between four infiltration facilities.

This thesis adresses the subject of stormwater management and the problematic with stormwatermanagment and landuse in the compact city. The thesis research different solutions in stormwater managment and how to implement them in the context of the compact city. And at the same time preserve and make good recreaational places and keep quality green land per capita. The thesis also analyses risks and problems that could effect the environment with focus on stormwater managment and hov to minimize these problematic factors an create a good environment. In an urban context where the water has a natrual place, and is used as a asset.

A titania-supported nickel catalyst was prepared and tested in methanation in order to evaluate its catalytic properties (activity, selectivity and specially, activity loss), and compare it with an alumina-supported nickel catalyst.The titania-supported catalyst did not only show higher stability than alumina, but also presented a different cause of deactivation, carbon formation. In addition, a kinetic model was obtained for the titania-supported catalyst, and a study of the effect of different operating conditions (temperature, composition and partial pressures of synthesis gas and water) on the deactivation rate and carbon formation of this catalyst was performed.

The purpose of this investigation was to find out more about students? spontaneous ideas about properties and transformations of matter. Examples of matter chosen are such which students know about from everyday life and focus is mainly on the questions if students know that all matter has weight and that matter is preserved in transformations.The method used is semi structured qualitative interviews with individual students. Different experiments were carried out together with the students who afterwards were interviewed. However, the students show varying answers and no generalizations can be done.

The purpose of this thesis was to examine how locally produced bioenergy may contribute to meet the climate target year 2050 in the municipality of Uppsala. The goal of reduced GHG-emissions from current 6,8 ton CO2-equivalents to 0,5 ton CO2-equivalents per capita and year, year 2050 is based on avoiding harmful penalties of an increased level of GHG in the atmosphere. By estimating available biomass in the county together with examining future technologies and emission factors for the substrates used, four possible future scenarios has been developed focusing either on electricity generation or production of biofuels. GHG-emissions of year 2050 have been calculated using the software LEAP. The conclusion is that bioenergy, depending on how it is integrated in the energy system, may reduce greenhouse gas emissions between 0.6 ton CO2-equivalents and 1.4 ton CO2-equivalents per capita or 12% to 25% compared to 5.5 ton CO2-equivalents in the reference scenario 2050. The greatest reduction is obtained if biofuels are produced in combination with energy efficient heat requirements in buildings..

I detta examensarbete undersöktes möjligheten att installera värmeåtervinningssystem för ett flerfamiljehus i Hovgården som ligger en bit utanför Borlänge. I rapporten redovisas två olika sätt för energibesparingar som är aktuella för att ersätta borttagning av oljepannan som används i huset i dag. En rad svårigheter dök upp under undersökningen för installation av nytt värmesystem. Lämpliga lösningar kunde hittas efter mycket analys. Syftet med rapporten var att undersöka möjligheten och lönsamheten för installation av något av följande system; FVP eller VBX-modul som kan återvinna värme ur frånluften.

Rooted in Industrial Ecology (IE) theory, this report evaluates how urban agricultural concepts and techniques, can contribute to improved ecological sustainability within the inner city boundaries of Stockholm. An overarching literary study as well as an interview was carried out, resulting in a qualitative analysis followed by suggestions for practical implementations. A substantial convergence was found between the eco-restructuring objectives of IE and the principal motives for urban agriculture. Consequently, eco-restructuring objectives are found in varying degrees in the presented urban agricultural techniques. Industrial symbioses, permaculture and combinations of urban agricultural techniques are tools which are capable of corresponding adequately to the diversity of urban settings.

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.

In this thesis proposals for different designs of a borehole thermal energy storage (BTES) have been developed for the building DN-huset in Stockholm, Sweden. To build a BTES results in savings in energy costs by approximately 44 %, i.e. 2 million Swedish crowns annually. Furthermore, a BTES would reduce the annual environmental impact with roughly 75-157 tonnes of CO2 equivalents per year, depending on how the electricity consumption?s environmental impact is estimated.

With the days DGPS-technology can a position of 5 centimetres decides. With this exactly position is the technology very interesting for the agriculture. I think this technology can come more and more in the future. You can also move the fact and information further to the spreader, sprayer and seeders. If the combine is equipped with harvest accounting, can you with help of the system make harvest maps.

With growing economies and better living standards in many parts of the world today, there is a need of expanding the capacity of generating electricity. The alternatives for renewable energy technologies are not fully developed and have still some problems to conquer.The company Minesto has developed a technology that is called Deep Green. It is designed to gain electricity from tidal currents. Deep Green works in a similar way as a kite that is attached to the seafloor with a moving wire. It contains of a wing that moves due to the water current.

This is a paper about the effects from smoldering fire on lithic objects from an archaeological view. The introduction gives the background to this paper, a short orientation to forest wildfires and why the work is limited to: flint, quartz, quartzite and slate. Material and methods describes the stone materials and the setup that was used in the temperature logged tests with three replications for each type of material. The fuel in the burnings was peat on a bottom of sand. Flint showed a more drastic effect from heat compared with the other materials. Slate seems to have greater tendencies to change to darker colour and luster at lower temperatures than the other materials.