Godkänd; 1998; 20070404 (ysko)

<p>Godkänd; 1992; 20080407 (ysko)</p>

No description available.

The pressure has a major impact when it comes to control of chemical processes. A method for integrating electrical pressure sensors in high-pressure microfluidic chips has, however, so far not been developed and the aim of this project was therefore to study how capacitive pressure sensors could be designed and fabricated to measure pressures between 1-100 bar. Based on analytical calculations and simulations of the thickness and the deflection of the diaphragms, touch mode capacitive pressure sensors were designed, and the fabrication involved exploring both isotropic plasma etching with SF6 and wet etching using KOH to fabricate a diaphragm on a Si wafer. The method which was found to be most suitable was to etch the diaphragm by plasma etching with SF6, even though a pressure resistance of only 23.4 bar could be accomplished, which is believed to be a consequence of the surface roughness, resulting in an Ra-value of 0.43 µm. The surface roughness lead to that chips had to be assembled by aligning them with an IR-camera and glued together with UV-epoxy, which enabled low precision. A method which do not leave any large etching effects on the diaphragm’s surface is therefore recommended for future work, to both potentially increase the pressure resistance and enable chips to be anodically bonded.

No description available.

I mitt examensarbete undersöker jag hur jag som möbelsnickare och produktutvecklare kan bidra i en designprocess. I samarbete med arkitekt- och designkontoret Claesson Koivisto Rune har vi utvecklat en trästol från en första skiss till färdig produkt, där jag har fungerat som produktutvecklare hela vägen igenom designprocessen. Examensarbetet visar på produktutvecklarens roll i en designprocess. ”Från idén om en förenklad konstruktion och sammansättning till en produktionsfärdig trästol med perfekt sittkomfort. Endast tre grunddelar – ben, sits och ryggstöd som gör stolen till en stabil helhet. En alternativ designprocess utan inblandning av industriell produktutvecklingsavdelning.”

The three boiling water reactors (BWR) in Oskarshamn produce about 10 % of the electrical power in Sweden. The combination of intense radiation fluxes and high temperatures in nuclear reactors creates an extraordinary environment. Therefore, a number of material challenges arise at a nuclear power plant that needs to be solved in order to maintain the nuclear power production, safety and reliability. Dissimilar metal welds can be found at a lot of places in nuclear power plants and due to reparations or replacement some dissimilar metal welds need to be welded on site. The technical regulations for the Swedish nuclear power plants specifies that welding of dissimilar joints shall be made with gap of at least 1.5 mm and in horizontal position. Welding a dissimilar joint on site makes it difficult to follow the technical regulations, therefore, the aim with this study is to determine if different welding positions of dissimilar metal welds affect the structure and composition of the weld metal in a negative way and to investigate the importance of a gap in the root. In this study six samples were welded in three different welding positions, horizontal, vertical and reversed vertical with or without a gap of 1.5 mm in the root. The samples were evaluated by non-destructive testing, optical microscopy, chemical analysis, tensile testing, bend testing and hardness measurements. The results shows that two of the samples welded without gap failed the transverse root bend test, the same samples did also have high hardness values in the root bead. The conclusions are that the welding position, horizontal, vertical or reversed vertical does not affect the weld negative in a noticeable way. However, the gap and a good dilution with the filler metal are important.

No description available.

No description available.

This paper is researching different kinds of biomass based fuels and contains a case study of a reheating furnace, furnace 301, at SSAB. The purpose was to find out which type of bio fuel was best suited for the furnace application. An experiment at KTH in Sweden was observed to better understand the process of creating a gas fuel from pellets and a mass balance was done to show the difference between using a new kind of bio mass based fuel and the current use of liquid petroleum gas. Results from the experiment and mass balance show that syngas is the fuel best suited for furnace applications as well as a general idea of how to integrate it into the furnace design. Three enlarged gasifiers, with a fuel output of 32 MW, will be needed to meet the requirements in an industrial application. If furnace 301 at SSAB would be active all year around with no stops in the production, an amount of 153760 ton pellets will be needed per year which is equal to 367407 tons of wood per year.