During the nineties, ecological handling of urban storm water became very popular in Sweden. Together with Chalmers University of Technology and two Swedish communities, DHI Water and Environment has been doing research of storm water ponds and constructed wetlands. This thesis work is a part of that research project. The work has been applied at the Bäckaslöv storm water treatment plant in Växjö, Sweden. The plant consists of one storm water pond and a downstream constructed wetland.

In this report a new gear concept is evaluated using the magnetic finite element method (FEM)software MagNet and Ansys as well as the mechanical FEM software Abaqus. The gear conceptis evaluated in terms of maximum torque capability, torsional stiffness, gear ratio and efficiency.ABB Corporate Research has proposed a new gear concept which should be less expensive thangearboxes used today. The new concept is called aMagnetic Harmonic Traction Drive and usesthe principles of a harmonic drive gear to achieve a high reduction ratio. The gear conceptreplaces the wave generator used in traditional harmonic drives with magnets and uses tractioninstead of gear teeth to transfer the torque. The main components in the gearbox are the magnets,the flexspline, the magnetic portion and the circular spline.

In Uppsala, Sweden, Vattenfall has a combined heat and power plant. On the premises there is an engineering workshop with old fluorescent and mercury lamps that need to be replaced. This provides a great opportunity to save energy and money by installing more efficient lighting. The main purpose of this study was to present two functional and energy efficient lighting systems including control system. The lighting systems were designed by investigating the working environment, measuring illuminance and by simulations in the software DIALux.

Detta arbete har utförts tillsammans med FOA 3 i Linköping som en undersökning av molntextur och molnklotter i flygbilder som registrerar värmestrålning. I dessa sammanhang betyder klotter en slags spräcklighet i bilden, eller att det inte går att se några mönster och strukturer i den..

By applying a segmentation procedure to two different sets of computed tomography scans, two geometrical models of the abdominal aorta, containing one inlet and two outlets have been constructed. One of these depicts a healthy blood vessel while the other displays one afflicted with a Abdominal Aortic Aneurysm. After inputting these geometries into the computational dynamics software FLUENT, six simulations of laminar, stationary flow of a fluid that was assumed to be Newtonian were performed. The mass flow rate across the model outlet boundaries was varied for the different simulations to produce a basis for a parameter analysis study. The segmentation data was also used as input data to a surface description procedure which produced not only the surface itself, but also the first and second directional derivatives in every one of its defining spatial data points.

 AbstractThis Master?s thesis analyses the dynamics of the medieval counterweight lever engine, ortrebuchet, a type of mechanical artillery. The purpose is to study the differences between different types of these machines, and see if computer simulations can be used to validate preserved advice on construction. Simulations include machines with a fixed counterweight, a hinged counterweight and a combination of both counterweights.Due to the almost complete lack of archaeological finds and insufficient historical source material there are still, after more than a century of research, many unanswered questions concerning the design and performance of these machines.The present study is based on an analysis by Jahsman (2004). A more detailed mathematical model employing Coulomb-friction is used.

This thesis examines the environmental benefits resulting from the choice of environmental certification scheme, with focus on energy. This was carried out by studying the measures that were implemented as a result of the certification of Sweco's three largest office buildings in Stockholm, Gothenburg and Malmö. The office property in Stockholm has been certified with the Swedish Environmental Building, Gothenburg with the British BREEAM and Malmö with the U.S system LEED.The results from the study indicate that an environmental certification can reduce the energy consumption by up to 59 percent and the water consumption by 20 to 66 percent. However; the interviews, literature study and simulations in MATLAB indicate that the size and scope of these environmental benefits depend on several identified factors: the type of building and its conditions, system selection, grade level, the choice of indicators, the ambition of those involved and when in time the certification process begins. The comparison between Environmental Building, LEED and BREEAM showed that Environmental Building for the office property in Stockholm gave the largest environmental benefit in terms of reduced energy consumption thanks to several large measures.

A Swedish electronics company wants to make the cooling of one of their electronic components more efficient. They propose that a retrofit liquid cooler is the way to achieve this goal. The current air cooling has high energy cost due to the high amount of power needed to power fans and heat exchangers. Using high volumes of air for cooling also leads to noise pollution. The conversion from air to liquid cooling would possibly make the operation of the electronics more cost efficient and less noisy.The purpose of this project is to theoretically evaluate different concepts of drawing the heat generated by the electronic component in to a fluid, using numerical calculations in Matlab and FEM simulations in ANSYS.

A new build in the Swedish nuclear power system would entail increased re-quirements for the proposed repository, which is adapted after the reactors of today. With a fast reactor, capable of burning nuclear waste, operating in parallel with the light water reactors, the increased requirements on the repository could be reduced.In this thesis, simulations of a light water reactor and a fast reactor have been performed by using the Monte Carlo code Serpent to investigate the changes in the fuel inventory. The light water reactor in the study is a boiling water reactor and the fast reactor of the type sodium-cooled fast reactor and they have been used for three different operation scenarios.By studying the fuel composition and the results from the simulations of the three scenarios conclusions can be drawn. Conclusions regarding the change of the fuel inventory and decay heat in Clab as well as the interim storage facility and in the repository. Depending on the operation alternative the changes dif-fered significantly and especially regarding the mass of burned actinides for different fuels in the fast reactor.The lowest increase of fuel assemblies was meet when using 50 years old fuel with 20MWd/kg U burnout and 2,0 % enrichment for start up of the fast reactor and 30 years old fuel assemblies with 50MWd/kg U burnout and 4,7 % enrichment for the further operation of the reactor.The increase of the number of fuel assemblies was 3174, which is equivalent to 641tons of heavy metal.

Syftet med vårt arbetat är att undersöka geografiämnets historia och utveckling samt att analysera vilken bild eleverna har av ämnet idag. Vi har valt att analysera kursplaner och läroböcker från 1900-talet samt utföra en enkätundersökning bland årskurs 9 eleverna på en större skola i Skåne. Vår undersökning av kursplaner och läroböcker visade att läroböckerna följer kursplanerna och att kursplanerna förändras med samtiden. Enkätundersökningen visade på att naturgeografin dominerar men att deras förståelse för geografi är förhållandevis god..

Detta examensarbete är gjort på uppdrag av skogsvårdsstyrelsen i Västra Götaland. Det övergripande syftet är att finna en metod som visar förekomsten av igenväxande hagmarker i Västra Götaland, samt ett sätt att beskriva tillståndet på dessa. Tillståndet skall beskrivas ur naturvårdssynpunkt och produktionssynpunkt. Tyngdpunkten ligger på naturvård. Även rådgivning om de praktiska åtgärderna behandlas..

The purpose of this work has been to explore what ecosystem services a small green area in an urban environment can offer and whether specific trees can be used to maximize regulatory ecosystem services in a cultural-historical environment. Additionally, it investigates whether there is any difference in ecosystem services depending on whether these trees, or trees that better fit into the cultural-historical environment, are used. Through simulations and comparisons with existing trees in Pommerska tomten, Mariestad, Sweden, a pocket park within a national interest area, different hypothetical tree planting options are analyzed and evaluated. To measure ecosystem services, the website My-Tree, developed by the US equivalent of the Department of Agriculture, was used. By inputting data about the tree, such as location, species, vitality, stem diameter, and solar exposure, My-Tree calculates some of the ecosystem services the tree provides.

Denna studie undersöker hur lärare arbetar med kartor i skolan och hur elever uppfattar användandet av kartor, både i skolan och i vardagslivet. Hur lärare uppfattar förändringen i mötet med kartan genom bytet från Lpo 94 och Lgr 11 kommer också att belysas. För att få svar på dessa frågor har åtta stycken intervjuer av lärare på högstadiet samt fyra fokusgrupper innehållande fyra elever styck genomförts. I intervjuerna uppger lärarna att det idag finns en bristfällig helhetssyn gällande kartan hos eleverna, fokus ligger ofta på ett litet område. Lärarna anser att denna utveckling inom ungdomars kartuppfattning påverkas av dagens teknik, som till exempel GPS där fokus ligger på start- och slutpunkten.

Frigoscandia Freezer AB have seen themselves as an entrepreneur company for a long time, but have lately begun to realise that they have to go against a more administrative era. With that insight they have begun to examine their enterprise in order to achieve this. The division Team Spare Parts has started a project with the intention of checking-up the inventory management, and improving it for the future. To get support for this and other point of views, they decided to let us do our exam thesis as a part of the project.The first part of the thesis deals with the appropriate inventory theory. All calculations in the other parts of the thesis have been based upon this.

This pre-study investigates the possibility of U-value measurements through an acoustic method. A hypothesis about an acoustic model built on acoustic theories combined with U-value theories is presented to answer the questions: ? Can U-value theory be combined with acoustic theories? ? Can the coefficient of heat be affirmed trough an acoustic measurement? The idea for this dissertation begun with a logical idea in mathematical similarity, between the coefficient of heat transmission units and sound intensity units. The U-value theory is based on assumptions such as initial resistance for inner walls and initial resistance for outer walls. The resistance in the material is interpreted through sound intensity theory. The argument is built upon mass law theory, which means if the frequency or thickness of the material layer doubles it implies an increase of sound reduction by 6 dB.