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.

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 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.

Denna examensrapport redogör för en utvecklingsprocess av en webbasserad släktforskningsapplikation, där resultat från släktforskning kan delas av flera aktiva släktforskare. Genom att grundligt undersöka olika datamodeller och befintliga applikationer försöker arbetet säkerställa grunden till en unktionell webbapplikation. Arbetet ledde till en betaversion med begränsad funktionalitet som skall vidareutvecklas i framtiden till ett GNU/GPL projekt med öppen källkod för gratis användning och nerladdning. Målet med arbetet uppfylldes i stora drag, det frångicks dock lite på grund av tidsbrist som uppstod i samband med prototypprogrammeringen..

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.

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.

The aim of this paper is to describe how to measure welfare effect of the deregulation and increased competition of the public transport by railway in Sweden. The paper also includes a numerical example of how to measure the welfare effect. In our study we use public data from SJ regaring quantity and ticket prices for the period 1996 - 2005. We have used equivalent variation, EV, as the method to measure the welfare effect. We demonstrate how to derive the equation to calculate EV by starting with a Marschallian demand function.

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.

Reading difficulties is the most common learning difficulty in the western world and it is common that people with reading disabilities also exhibit arithmetic difficulties. Different theories about the cause of the relationship exists, one theory describes the importance of good phonological ability in reading as well as in arithmetic, while another theory describes the importance of a reliable number system and that only a subgroup of students with reading disabilities also have difficulties with arithmetic. The purpose of this study is to investigate how students with reading difficulties (RD), without any known mathematical difficulties, perform on mathematical tasks relative to a control group. The study was theoretically grounded on the Triple code model (Dehaene, 1992), which is a model for numerical information processing that describes how various numerical and arithmetic tasks are processed through three distinct representation systems in the brain, a verbal and a visual representation system and a quantity system. Reading skills, phonological skills, arithmetic skills and number processing skills were examined in 61 students through a variety of tests.

To design new and high tech products the engineers rely more and more on computer based simulations to investigate the properties and behavior for a component or system.To verify these computer based simulations the dynamic properties for the components of the drivetrain needs to be verified. Therefore measurements of the stiffness and vibrations for the rear axle has been performed. This report show how the measurements has been implemented and evaluated, along with some interesting results for the rear axles properties.The static stiffness for the drive shaft along with the axle-gear has been determined. It is found that the stiffness for the whole rear axle is near the stiffness for the drive shaft, which means that the drive shaft becomes the dominant component of the system and affects the rear axle stiffness the most. The measured stiffness of the driveshaft is close to its theoretical stiffness.The stiffness for solely the hypoid-gear have been calculated using the stiffness for the rear axle and driveshaft, and thus has a range for the stiffness of the hypoid gear been determined.The backlash for the whole rear axle and for some individual components has been determined, where the backlash between pinion and crown-wheel has negligible impact on the total backlash.Measurements of the crown-wheel and pinion movements have been conducted, where the direction of movement is consistent with the theoretical direction of the forces.The vibration measurements show that the vibrations are more severe at certain rotational speeds.

In several scientific and technical educations today we meet mathematical studies in differential- and integral calculus. The classic mechanics is a foundation for the physics and it has made it possible for today's technical developments that we in our everyday life meet and make use of. The intention for this essay is to give a picture of the person behind this discoveries that changed the science and the world. Besides the purpose to bring the reader on a journey through Isaac Newton's life the main intention is to give an understanding of the way he discovered the binomial theorem, the differential- and integral calculus, the numerical methods Newton-Raphson's and Newton's interpolation-polynomial, Newtons identities and his classification of third-degree curves and elliptic curves. A derivation of Kepler's first law is also included..

Planet rendering plays an important role in universe visualization and geographic visualization. The recent tools and methods allow better data acquisition, usually with very high resolution. However in computer graphics, there is always the limitation on the resolution of geometry and texture due to numerical imprecision. Not many applications can handle high resolution data effectively.This thesis introduces, Implicit Surface Scene, a level of detail scene management inspired by dynamic coordinate system and SCALEGRAPH? which change over time depending on the current camera position relative to the planet surface.