This thesis deals with numerical simulation of earth pressure against tubular bridges in the software Plaxis. Plaxis is a FEM (Finite Element Method) software based on numerical calculations for which approximate solutions are developed through an iterative process. The program is specifically designed for soil and rock mechanical tests, such as voltage and deformation calculations in soil.The Royal Institute of Technology conducted in 2005, field tests on tubular bridges of corrugated steel, which was part of Ersa Bayoglu Fleners PhD (Bayoglu Flener, 2009). She studied how two different tubular bridges deformed during installation and filling. Tests and measurements were made during filling.

In this thesis a rural network in Norrbotten, Sweden, has been to designed and planned with the purpose of improving distribution reliability by exchanging existing overhead lines with underground cables. General network design considerations are discussed as well as the ones for the specific low voltage grid. During the design phase the maximum power of domestic consumers has been estimated using Velander?s method. Currents, voltage drop and impedance of the network have been calculated and fuse operation and selectivity has been considered.

The purpose of this study is to examine young adults', 18-19 years old, attitudes towards corporal punishment and with the help of social constructionism, grid-group theory and relevant concepts analyze the results and compare it with previous research. The research questions introduce various factors such as gender, origin and personal experiences of corporal punishment that may affect the attitudes. In order to fulfill the purpose and answer the research questions, a quantitative research method has been selected. There was 118 participants in the survey. The study was conducted by means of surveys in high schools in Örebro. Social constructionism made us realize how the community, perceptions and expectations might influence attitudes. Grid-group theory gave us an insight into how different family structures may explain why attitudes toward corporal punishment of children differ between individuals.

Due to historically low prices for electricity in Sweden, many small-scale hydropowerplants were closed down. A small-scale power plant has more or less the samemaintenance costs as larger plants, but doesn?t generate as much income. Today?sincreasing price for electricity in combination with a desire for renewable energysources makes small-scale hydropower interesting again.

Dyskalkyli (specifika ra?knesva?righeter) a?r en av flera orsaker till matematiksva?righeter. Studier har pa?visat samband mellan dyskalkyli och dyslexi och att personer med dyskalkyli har sva?rt att klara skolmatematiken. Tva? skilda synsa?tt fo?rklarar orsaken till dyskalkyli: systemteorin och modula?rteorin.

During the period 2009-2013, investments in the Swedish national grid increase by a factor of ten compared to previous years. In order to fulfil their mission to manage the national grid in a safe, efficient and environmentally sound way, Svenska Kraftnät (Swedish National Grid) needs to take all these perspectives into account while planning new investments. To compare and relate perspectives of technology, economy and environment the same yard stick must be used. That yard stick is commonly money. A problem arises however as environmental issues are difficult to price.The purpose of this master?s degree project was to develop a tool for evaluation of environmental impact related to investments in the Swedish national grid.

An important process for grid companies in order to reduce power losses in electricity distribution grids is to figure out where and how they appear. This report describes the factors that cause power losses in low voltage distribution grids and methods for how they could be measured and analyzed. Measurement data for consumed and injected energy were collected for twelve low voltage distribution grids owned by Gävle Energi AB in order to analyze the size of the power losses and how the measurement uncertainty affects the collected data. Then models of three of the grids were created in MATLAB in order to analyze the data and the power losses were calculated to be compared to the collected data. Curve fitting were also used as a method in order to analyze the power losses from collected data.The results show that the losses in the studied grids are low.

Syftet med denna studie har varit att undersöka de svenska politiska partiernas åsikter gällande den förstärkning av personvalsinslaget som infördes år 1998 samt att fastslå hur dessa ställer sig gentemot en ytterligare reformering av valsystemet. Valreformer är historiskt ett politiskt område inom vilket det förekommit stora motsättningar enligt den traditionella ?höger vänsterskalan?. I studien analyseras huruvida dessa kvarstår efter den senaste reformen. För att ytterligare studera partiernas åsikter har dessa även analyserats i enlighet med Grid-Group teorins analysverktyg.

Comfort analyses regarding human induced vibrationsIt is not too common among civil engineers in Sweden to perform comfort analyses considering the vibrations caused by human activities. In addition, the Swedish standards lack requirements to be used for comfort analyses in design of floor-systems. The demand for large spans in combination with slender slabs, is today a reason to investigate the floor-system constructions, in order to prevent disturbing vibrations and oscillations.The purpose of this thesis is to create a guide for how a comfort analysis, considering vibrations, should be implemented. Göran Svedenbjörk who is an expert in structural dynamics has been interviewed where he presents his latest project Värtaterminalen and answers some questions about vibrations due to human activities.Floor-systems, consisting of concrete slabs supported by steel or concrete beams, have been investigated with simulations in the finite element program Abaqus. In the simulations, the influence of various factors on the natural frequency of floor-systems and the acceleration level caused by dynamic loads, is studied.

The voltage level in the power grid varies due to variations in load and production. Normally these variations are manageable, but they may be excessively large during a disturbance. If the voltage is too high it may damage the equipment in the grid and too low voltages may cause problems like voltage instability. The magnitude of the voltage variation depends on the short circuit power capacity of the point of interest.This problem may become lore prominent due to automatic voltage regulation that acts on shunt reactors and shunt capacitors. When the shunt reactor is connected or disconnected to the grid it may cause such large changes in the voltage that the shunt reactor starts hunting.

The aim of the project was to develop a method to investigate differences in adhesion of microorganisms to materials that contains lignocellulose. The method was tested on a gram-positive (Micrococcus lutea) and one gram-negative (E-coliJM109) bacteria.The study was begun by cultivation of the two microorganisms. The cultivation was done to calculate the generation times of the bacteria and to obtain growth curves. Cells from these cultivations were also frozen (-70ºC) and later used for inoculation.At STFI-Packforsk AB the total charge on the mass was measured and later a conductivity titration on the mass was executed as well, all to find out more about the different properties of the mass. Properties that in a later part of this study could possibly be linked to the adhesion of cells to the pulp.

Värnamo Elnät owns and operates a ripple control system which is used to control loadsespecially when the grid is heavily loaded and for control of street lighting. This report aims atclarifying technical and economic aspects of the ripple control system?s future. The system wasinstalled from 1975 and onwards and its use was greater in those days when the controllableloads where greater then today, the current controllable load level is about 3 MW. The reporthighlights three different aspects of the ripple control system?s future ? retain the currentsystem, reinvest in a newer system or discontinue the system.In the report the author also discusses relevant connections to Smart Grids and future meteringsystems and tariffs.

The thermal response of a borehole field is often described by non?dimensional response factors called gfunctions.The g?function was firstly generated as a numerical solution based on SBM (Superposition BoreholeModel). An analytical approach, the FLS (Finite Line Source), is also accepted for generating the g?function. In thiswork the potential to numerically produce g?functions is studied for circular borehole fields using the commercialsoftware COMSOL.

Målet med detta examensarbete, utfört på uppdrag av Vectura Consulting AB, har varit att undersöka möjligheten att ansluta en vindkraftpark till järnvägens kontaktledningsnät. Möjligheten att koppla om vindkraftparken till järnvägens hjälpkraftnät, som bland annat förser växelvärmare och signalsystem med effekt, har också undersökts. Eftersom kontaktledningsnätet och hjälpkraftnätet arbetar med olika frekvenser och spänningar, 16? Hz och 15 kV respektive 50 Hz och 22 kV, måste därför en komplett krets för frekvensomvandling, spänningsomvandling och omkoppling tas fram. Projektet har begränsats till en del av Botniabanan, sträckan Örnsköldsvik-Nordmaling.I denna rapport har trafikfrekvensen på den valda sträckan på Botniabanan undersökts för att bestämma en genererad effekt till inkopplingspunkten, samt för att undersöka när det kan vara lämpligt att koppla om till hjälpkraftnätet.

Målet med detta examensarbete, utfört på uppdrag av Vectura Consulting AB, har varit att undersöka möjligheten att ansluta en vindkraftpark till järnvägens kontaktledningsnät. Möjligheten att koppla om vindkraftparken till järnvägens hjälpkraftnät, som bland annat förser växelvärmare och signalsystem med effekt, har också undersökts. Eftersom kontaktledningsnätet och hjälpkraftnätet arbetar med olika frekvenser och spänningar, 16? Hz och 15 kV respektive 50 Hz och 22 kV, måste därför en komplett krets för frekvensomvandling, spänningsomvandling och omkoppling tas fram. Projektet har begränsats till en del av Botniabanan, sträckan Örnsköldsvik-Nordmaling.I denna rapport har trafikfrekvensen på den valda sträckan på Botniabanan undersökts för att bestämma en genererad effekt till inkopplingspunkten, samt för att undersöka när det kan vara lämpligt att koppla om till hjälpkraftnätet.