In the electronic industrials, power control of AC motors is commonly used. For example power control of a washing machine motor, a vacuum cleaner motor or a coffee machine motor. The company Rejlers Ingenjörer AB has many projects where power control of AC motors is included. A prototype card for this task can save time and money for the company in the future and this is the reason for this thesis.The motors are power controlled by a TRIAC and control of the trigging pulses to the TRIAC. This card is modularly built and can easily be adapted for future projects where the power control of AC motors are included.The prototype card can be used as a subsystem in a larger electronics projects or as it is in lab environment for testing and evaluating new motors..

This master thesis is about a place that has a story to tell. Olsson?s garden came about when Mr Carl Oscar Olsson acquired a piece of land in Landalabergen in the beginning of the 1930's and at that time he started his industrious work of uniting much of Sweden's flora in his garden. Since the very beginning Olsson's garden has played a lot of different rolls in a variety of situations and meant different things for different people. Today one can find traces from Mr Olsson's life and deeds in the garden.

The purpose of this thesis was to make an energy survey and quantify energy flows of individual unit operations associated with the biogas production in Uppsala Vatten och Avfall AB:s biogas plant, located at Kungsängens gård. Moreover, large consumers of energy would be identified and analyzed. The objective of this energy survey was to obtain a detailed understanding of the energy use in the biogas production.The energy survey was divided into two parts: electricity and heat. Each part was treated separately and with somewhat different approach. To estimate the electricity usage during the projcet the rated power of each selected unit operation was noted and multplied with thenmeasured time of usage.

The purpose of this thesis was to make an energy survey and quantify energy flows of individual unit operations associated with the biogas production in Uppsala Vatten och Avfall AB:s biogas plant, located at Kungsängens gård. Moreover, large consumers of energy would be identified and analyzed. The objective of this energy survey was to obtain a detailed understanding of the energy use in the biogas production. The energy survey was divided into two parts: electricity and heat. Each part was treated separately and with somewhat different approach. To estimate the electricity usage during the projcet the rated power of each selected unit operation was noted and multplied with the measured time of usage.

The aim of my study is to investigate how last year students in upper secondary schoolunderstand certain mathematical concepts, in particular the unit circle and its trigonometry.I have used intentional analysis to interpret student?s actions when they solve certain tasks onthe basis of a cognitive, situated and cultural context.Interviews with four university teachers in mathematics about the unit circle, trigonometry,and mathematical understanding, serve both as background for the study and as basis for adiscussion, where I relate students understanding to what the teachers want new students toknow about these concepts when they begin university studies in mathematics.The students were arranged in three groups with three students in each group. Each group waspresented with two tasks, one in which they were asked to calculate the cosine values for onepointed, one blunt and one straight angle, each located in a separate triangle. They were alsoasked to decide whether the points (0,71; 0,71) and d (1 2 , 3 2 ) are located on the unit circleor not.My conclusion is that students mainly have an operational conception of the unit circle andtrigonometry. The lack of structural conceptions result in difficulties in seeing connectionsbetween the concepts in unfamiliar situations.

The aim of my study is to investigate how last year students in upper secondary schoolunderstand certain mathematical concepts, in particular the unit circle and its trigonometry.I have used intentional analysis to interpret student?s actions when they solve certain tasks onthe basis of a cognitive, situated and cultural context.Interviews with four university teachers in mathematics about the unit circle, trigonometry,and mathematical understanding, serve both as background for the study and as basis for adiscussion, where I relate students understanding to what the teachers want new students toknow about these concepts when they begin university studies in mathematics.The students were arranged in three groups with three students in each group. Each group waspresented with two tasks, one in which they were asked to calculate the cosine values for onepointed, one blunt and one straight angle, each located in a separate triangle. They were alsoasked to decide whether the points (0,71; 0,71) and d (1 2 , 3 2 ) are located on the unit circleor not.My conclusion is that students mainly have an operational conception of the unit circle andtrigonometry. The lack of structural conceptions result in difficulties in seeing connectionsbetween the concepts in unfamiliar situations.

The aim of my study is to investigate how last year students in upper secondary schoolunderstand certain mathematical concepts, in particular the unit circle and its trigonometry.I have used intentional analysis to interpret student?s actions when they solve certain tasks onthe basis of a cognitive, situated and cultural context.Interviews with four university teachers in mathematics about the unit circle, trigonometry,and mathematical understanding, serve both as background for the study and as basis for adiscussion, where I relate students understanding to what the teachers want new students toknow about these concepts when they begin university studies in mathematics.The students were arranged in three groups with three students in each group. Each group waspresented with two tasks, one in which they were asked to calculate the cosine values for onepointed, one blunt and one straight angle, each located in a separate triangle. They were alsoasked to decide whether the points (0,71; 0,71) and d (1 2 , 3 2 ) are located on the unit circleor not.My conclusion is that students mainly have an operational conception of the unit circle andtrigonometry. The lack of structural conceptions result in difficulties in seeing connectionsbetween the concepts in unfamiliar situations.

The Intensive Care Unit (ICU) is a special unit for patients who is in the need for emergency life-sustaining measures and every patient has complex medical- technical equipment. The experiences of a critical illness and the needs of critical care are experienced in different ways. The purpose of this study was to describe the experiences from patients in the ICU and how this experience has an influence on the patients. The method was a study of literature with a qualitative inception based on eight scientific articles and the analysis of content has been inspired by Graneheim and Lundman (2003). The result of the study is presented by four categories: to loose the ability to make themselves understood, to be forced to adjust to the environment of caring, to have the lack of connection with reality and to be in an intensive care environment, The results showed that patients in the ICU are affected by the attitude from the staff, the equipment around them as well as the sounds and lights in the environment there.

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.

In this paper I study how the repeal of the Swedish wealth tax (1 of January 2007) has affected people´s labour supply behaviour. This particular issue is relevant because it may help us understand some of the effects of the earnings tax changes that have taken place in Sweden. Accoring to standard economic theory a repealed wealth tax is similar to an income effect for the persons who previously paid the tax. That means that they theoretically will want to consume more leisure, that is decrease their labour supply. The method I am using to test this hypothesis is a difference-in-difference approach where the treatment group consists of persons who previously paid the tax and the control group of comparable persons who did not pay the tax.

This thesis is the result of the author?s interest in music and electronics, namely the design and manufacturing of a stereo sound system with an active crossover. In short it can be stated that an active crossover has many advantages over its traditional passive counterpart. The active design naturally results in a more complex system comprised of a multiple number of components. This report deals with the theoretical aspects of preamplifiers, crossovers and power amplifiers as well as power supply and control.

Abstract Author: Annika Sjögren ArvidsonTitle: The reflective leadership role in social service organizations Supervisor: Anders GiertzAssessor: Jan Petersson  I have studied the leadership role of unit managers in social service organizations and their relationship to the concept of reflective approach. I started from a curiosity about how and if unit managers within social services use the concept reflective approach in their leadership role, and how their organizations look upon this and what the consequences are. If in the long term, this affects the individual receiving assistance. All the interviewed persons come from different places, services and organizations. The study is qualitative, with a number of interviews conducted with unit managers.

Violence against teachers in Swedish schools, according to recent reports has increased and there have been many studies to investigate the situation for teachers. The surveys show that teachers are especially vulnerable to students. This study aims to examine the relationship between a number of teachers and their students to study the power relations that exist in the classroom. This is to see what violence is an expression of and also how violence is perceived by the teachers. The issues that are central in this study are:What is the importance of dialogue in the relationship between these teachers and their students?Is there power relations between teachers and their students?What is the violence against teachers and expression of?Is there any connection between dialogue, power relations and violence?The theories of the materials in this study was analyzed using power relations theories of the historian of ideas Michel Foucault and Philosophy Doctor Anders Persson, who to some extent has his theoretical basis in Foucault?s power relations.

The purpose of this thesis is to identify power structures and instruments of power within the Jehovah?s witnesses and investigate how they affect the baptized youths baptized within the organization. The material consists of qualitative in-depth interviews and is analyzed with Foucault's theories of power. The results show that the participants have a very strict relationship to the rules of the congregation and also that they take great care in observing these rules carefully. It becomes evident that young members are exposed to disciplinary measures from the organization.

Recent years there has been discussed how the critical situation in the housing market threatens the Stockholm region's growth. The thesis objective is to examine whether there is a scientific link between the lack of housing supply and growth. The thesis also intends to identify solutions for increased housing construction, for instance by examining the conditions for a greater regional perspective and influence on the region's housing supply. The thesis empirical study is based on semi-structured interviews with representatives from the Government, municipalities and the housing industry.In Sweden, research on the relationship between housing shortages and growth has not been conducted to that extent it can be said to exist scientific evidence regarding the growth threat. However, in Britain and the U.S, empirical studies show that a lack of housing supply has hindered growth through negative impact on countries' gross domestic product.