This thesis is performed in collaboration with Kraftpowercon AB in Surte, Sweden. Focus has been on to identify the powerlosses in one of Kraftpowercons halfbridge DC-DC converters. First theoretical calculations are made, the calculations is verified with measurements of six different operation modes. In a later stage, methods like soft switching and synchronous rectifying are proposed to increase the efficiency for the converter. To achieve softswitching for the halfbridge, the LLC resonant converter topologies are implemented and examined.

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.

Titel: Value stream mapping in practice ? A case study at Light MyFireAuthors: David Rydman and Tomas ÖnnemarMentor: Veronica Ülgen SvenssonExaminer: Åsa GustafssonBackground: Companies push their prices in today's markets to be competitive, which means that companies need to find ways to reduce costs while maintaining profits. (Cudney, 2009) According to Bergman and Klefsjö 2007, the basic rule of quality improvement says "there is always a way to achieve higher quality at a lower cost". One way is to improve a company's processes to get a more efficient flow and improvements that may cut costs. (Bergman & Klefsjö, 2007) Why it's important to look at the processes are that they often contain waste that can be eliminated.

Sala Silvergruva AB är ett av många företag som just nu kämpar med höga energi-kostnader. Denna rapport undersöker vilka möjligheter det finns att skapa ett hållbart energisystem i Sala Silvergruva med avseende på ekonomi, miljö samt sociala aspekter. Rapporten undersöker nio tekniker; vindkraft, vattenkraft, solfångare, solceller, pelletspannor, värmepumpar, effektivisering samt lagring av värme från växthus respektive fjärrvärme. Dessa analyseras var för sig med utgångspunkt i tio krav som speglar hållbarhetsaspekterna. I samband med analysen ges rekommendationer angående investering i respektive energilösning. Rapporten mynnar ut i en resultatskarta där det tydligt framgår vilka krav de olika teknikerna uppfyller. Den följande diskussionen leder fram till en slutsats som presenterar vilka åtgärder som bör vidtas i syfte att skapa ett uthålligt energisystem för Sala Silvergruva AB. Pelletspannor och värmepumpar visar sig i nuläget vara de mest uthålliga tekniklösningarna.

SAPA´s resource of waste heat is the basis for this thesis to investigate the possibility of energy assets in their cooling water and possible uses for it. The energy in the waste water is greater than the current need which has three uses which are (1) heating the factory, (2) converting liquid propane to propane gas and (3) local domestic heating. The average energy load that is available is 1, 7 MW and the average temperature in the cooling water is 41°C. The total energy load at dimensioning out side temperature is approximately 1,6 MW for the three current uses. The temperature is currently too low to be used directly in the existing systems so an upgrade is needed.

Background: A common view about people with diagnosed psychosis is that they are socially withdrawn and that they neither cope nor want to engage in social relationships. Newly published specialist books on this subject also support this view.Aims: To unveil further dimensions of the phenomena by explorative analyzing consumers? own depictions about their ?social relationships".Method: The material is taken from a larger study that followed consumers regularly during a lapse of 3 years. Within this material 15 interviews from three respondents were chosen, a selection which gives maximal spreading concerning age, sex and background. The interviews where analyzed by methods based on Grounded Theory.Results: Three main dimensions were identified: supportive relationships, difficulties and social withdrawal.

The purpose of this study was to investigate the association between physical activity and perceived stress, energy and musculoskeletal disorders among office-workers and warehouse-workers and also to see if there were any differences depending on work-place and gender. The method that was used to collect data was three different validated questionnaires that measured stress and energy (the Stress-Energy questionnaire), musculoskeletal disorders (intensity and localization of pain, a Pain Drawing questionnaire with a VAS-scale) and physical activity (IPAQ ? the short version). Eighty-eight workers participated in the study. Forty-seven of them were office-workers and forty-one were warehouse-workers.

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.

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.

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.

Since the turn of the millennium a sharp increase in the interest for bio energy has been observed. Important reasons for this growing interest can be due to the fact that fossil fuels are a finite resource. A net discharge of greenhouse gases occur when fossil fuels are burned. The discharge of greenhouse gases are considered to be the main reason to the greenhouse effect. Means of control to increase the use of bio energy has been introduced and, as intended, the use of bio energy has increased. As a result of the legal provisions the ability to pay for bio energy has increased, which the forest industry view as a problem.

This Masters thesis work describes a comparison between two different methods for estimation of the down channel (base station to mobile subscriber) in Wide-band Code Division Multiple Access (WCDMA). The first estimation method, Optimal Feed-forward Channel Estimation (OFCE), is a conventional method that bases the estimates on data that is known to both sender and receiver, so called pilots. The second method, Decision Directed Channel Estimation (DDCE), is an elaboration of OFCE. It also uses user data for estimation. Simulations show that DDCE, in comparison to OFCE, does not attain an improvement in signal-to-noise-ratio (SNR) for high bit error rates (BER).

 AbstractThe background for this study is that there were a great amount of buildings constructed in Sweden in the years 1965-1975 in a program designed to create one million apartments in a time-period of ten years. These buildings are now, somewhat forty years later in most cases in very poor condition and the need for renovation is great and urgent. This has become a growing problem and more and more voices are being heard pointing towards the vast and extremely expensive task of renovating these buildings. Lately, it has also been more and more important for buildings to be energy-efficient and sustainable environment friendly.In recent years there has been an atempt to solve these problems by renovating such buildings but at the same time making them very energy-efficient. This is in some cases being done by isolating the shell of the building and changing the ventilation-system and so forth.

The purpose of thesis was to investigate and compare how two companies within pharmaceutical industry and nuclear power industry are currently working with quality development regarding continuous improvement and Lessons Learned in business processes. In addition, a simple comparison was made with the automotiveindustry.McNeil AB are improving their processes continuously and are according to the findings of this report performing well in their pursuit of world-class pharmaceutical production. They have a well functioning process regarding improvements proposed in weekly improvement meetings engaging all employees. However, during interviews it was made clear that the functionality of the process which administer improvement proposals generated in addition to, or beside the weekly improvement meetings, were inadequate. McNeil AB is proposed to administer this through an IT solution instead of by paper and e-mail, that simplifies the process of adding, implementing and follow up an improvement proposal.The nuclear power plant Ringhals AB recently made major improvements in their business processes as well as the plant itself.

Beef production in Sweden has traditionally been about rearing of dairy calves to slaughter. With reduced number of dairy cows and accordingly less dairy calves for slaughter, there has been a need for new forms of beef production in Sweden. In Västerbotten there are good conditions for beef production with a high feeding level of roughage due to favourable climate. The aim of this thesis is to, through interviews with ten farmers with beef production in Västerbotten, study what and with how much they feed their animals and link the results to production level. The thesis begins with a literature review where the general feeding standards and feeding recommendations for beef cows and growing cattle are examined.