ABB Surge Arrestors in Ludvika have for a long time had a problem to keep the moisture at a steady state in the production of their ZnO-powder, that is used to produce varistors.Some black-box models of the spray drying process have been designed and evaluated to find a solution for the problem. After evaluating the collected data it has been found that variations in the supply voltage causes control difficulties for the operator. A cascade control system was designed, consisting of three PI control loops designed with lambda tuning. The disturbance in the supply voltagewas used as a feed forward in the control system.At the end of the project the control system was installed, and tests were made to verify the functionality of the regulator. It was shown that most of the variations in the moisture of the powder could be eliminated using small resources, through purchase of a process controller and four power meters.

Scandinavian Ragdoll Club rekommenderar screening av njurarna med ultraljud hos ragdollkatter inför avel, detta för att leta tecken efter kronisk interstitiell nefrit (CIN) som misstänks drabba dessa katter i högre utsträckning än andra raser. Den undersökande veterinären ska bland annat göra en subjektiv bedömning av förhållandet mellan bark och märg. Syftet med denna studie var att upprätta normal- och referensvärden för volymmässigt förhållande mellan bark och märg hos friska katter då detta saknas. Tre snitt (sagittal-, dorsal- och transversalsnitt) av vardera njuren sparades och mätningar för längd, höjd och bredd för både total njurstorlek samt märgstorlek utfördes. Volymen för hela njuren, märgen samt barken beräknades genom att likna njuren vid en ellipsoid och normalvärden för förhållanden mellan bark och märg räknades ut.

This essay aims to investigate a rare method of marking up timber before hewing it. The method for marking up timber is by eyesight, where visual judgment and the use of a broad axe are the tools employed. The broad axe is driven through the bark and exposes the inner bark in a straight line. The method is described by a craftsperson dating back to the 1930s. There is a lack of information regarding the method.

Earlier investigations showed that damages on timber from feeding rolls could be within the lower classes of damage according to VMRs classes. Knowledge about differences in productivity between kind types and aggressive types of feeding rolls is necessary because it should influence the question about damages on timber caused by different feeding rolls. In this study the production and timber damage in a harvesting head were evaluated at three levels of pressure (8, 10 and 14 MPa) on the feeding rolls, and with three different types of rolls. One type, the rubber cushioned steel plate roller had 10 mm studs and rubber damping, one ?middle? type made of solid steel with 14 mm studs, and one aggressive type, also made of solid steel with 18 mm studs.

Storage of biomass is associated with problems like heat development, biomasslosses, and reduction of the fuel quality. Certain processes such as biological- andchemical degradation are responsible for these storage problems. This master?sthesis was carried out at Vattenfall Research and Development AB and is alignedtowards quantifying the biomass losses from short-term storage (1-2 months) ofbark and recovered wood. The biomass was stored in outdoor piles during differentseasons, campaign 1 (summer) and campaign 2 (autumn).

The bioenergy market has been introduced relatively late in a perspective of the Swedish forestry. Nowadays branches and tops are used more frequently as bioenergy after harvesting. Therefore, it has developed a competitive situation between pulpwood and bioenergy. This situation has even established some questions. Two examples of these are: ? At what top diameter should the final piece of pulpwood be crosscut to get the best economically result? ? Should the top diameter, at the final piece of pulpwood, be crosscut at a thicker or smaller diameter than what is done today? The purpose of this report is to answer these two questions when the harvesting is made motor manually in beech stands.

Uppgiften bestod av att göra en undersökning av barkhanteringen vid Billerud Karlsborg AB med avseende på ekonomi och barkens torrhalt. Undersökningen omfattar allt från stock till förbränning och eventuell försäljning av barken. Tidigare så förbrukades all bark i barkpannan, där ånga produceras för torkning av pappret och elproduktion i ångturbinen. I dag har stora delar av pappersbruket byggts om och effektiviseras, vilket medfört att bruket producerar mer ånga än vad som behövs och vad turbinen klarar av att förbruka. Den bark som inte förbrukas av Billerud försöker man sälja och barken som blir över lagras i en stor barkstack.

Blast furnace is the heart of every steel plant. Steel production is based on the blast furnace process, as it is where the iron is extracted from the iron ore and turned into liquid iron, which will subsequently be used to make liquid steel. Therefore, without hot iron, steel can not be produced. Blast furnaces in this process are supplied among others with pulverized coal. Raw coal should be prepared for the blast furnaces in the form of fine coal powder.

Ett vanligt problem på mjölkgårdar är att trampskador uppkommer på betesytor som är kraftigt belastade av mjölkkor under betessäsongen. Den genomsnittliga besättningsstorleken i Sverige stiger och det leder till att problemet med trampskador ökar. Risken för trampskador tilltar vid stora mängder nederbörd. För att undvika trampskador på marken går det att dränera och ta bort matjorden och lägga dit ett markstabiliserande material. Bark som markstabiliserande material har i tidigare studier visat sig vara bra om barken är ordentligt packad.

The aim of this study was to quantify the productivity and the costs of different harvesting systems (teams), containing harvesters equipped with accumulating harvester heads and forwarders, in first commercial thinnings were an integrated harvest of pulpwood and energy wood were performed. In the beginning the plan was to study and measure 20 sites before and after harvest. Due to storms during the summer of 2010, complete data could only be obtained from 8 of these 20 sites. Seven of these sites were privately owned and one was owned by UPM, all of the sites had been pre-commercially thinned. The mean stem density before harvest was 2578 stems per ha and the mean stem volume was 0.074 m3solid over bark.On average 1518 stems/ha was harvested.

Ett vanligt problem på mjölkgårdar är att drivningsgator, grindhål, ytor kring vattentråg och andra högt belastade ytor blir söndertrampade under betessäsongen. Detta kan bidra till problem som sänkt djurhälsa, försämrad mjölkkvalité och dåligt fungerande kotrafik. De söndertrampade ytorna är även känsligare för jorderosion och näringsläckage. För att undvika denna typ av problem kan markstabiliserande material anläggas på dessa ytor. Detta examensarbete är en del av projektet Kamp mot tramp, ett projekt finansierat av Stiftelsen Lantbruksforskning.

The aim of this study was to describe preferences of geographic direction of ten, oak-living epiphytic lichen species and how they responded to sun exposure, nearby bushes and trees, bark fissure depth and circumference. The frequency of every species was recorded in arcs of ten degrees around the tree at a height of 130 to 180 cm above the ground. An estimation of the amount of every species in every arc was also recorded. To analyse how the distribution of the lichen species responded to the different factors their concentration for every tree was plotted against the four factors. The distribution of Cliostomum corrugatum had a positive response to high sun exposure and a negative response to a thick layer of bushes and trees.

One key factor in silviculture today is sustainability. In order to achieve sustainability it may be important to restore lost nutrients to the forest after clearcutting. In order to calculate the removal, you need to know how much of different elements you will find in different tree compartments. The aim of this study was to investigate if the concentration of elements in different tree compartments of spruce (Picea abies (L.) Karst) were related to the moisture conditions of the site. Five plots at Risfallet (60º 21´ N, 16º 13´ E), was placed along a moisture gradient in a 40- year spruce stand.

With higher prices for oil and increased focus on fossil fuels impact on the environment the heating sector are searching for alternative fuels. Pellets are a quite new product whose production has risen exponential in recent years. Today there are small-, medium-and large-scale users, where the large-scale consumers are the heating sector. The heating sector is mainly using oil to cover the increased demand during cold periods. The purpose of this study is to analyze the potential of pellets if it would replace thermal power plants oil and coal. The study will also analyze the economic impact a conversion would mean for a heating plant and if the pellet is a reasonable substitute. 2008 statistics from the Swedish district heating association were analyzed and a calculation was performed to determine how many tons of pellets is needed to replace coal and oil.

Not much is today known about how epiphytic lichens are effected by fire. A considerable part of the fires in Sweden today are prescribed fires for the purpose of environmental conservation. How these fires affect lichens is largely unknown. The aim of this study is to find out how epiphytic fruticose and foliose lichens on Scots pine are affected by fire, and to elucidate the relationship between fire intensity and the survival of lichens and later re-colonization. The study was performed at three locations just outside Umeå in Västerbotten that were burned 5-7 years earlier. In all locations there were larger groups of surviving Scots pines with varying amount of fire-damage in the crown, which enabled a reconstruction of fire intensity.