Sök:

Sökresultat:

335 Uppsatser om Chemical Vapour Deposition - Sida 1 av 23

Tillståndskontroll av vätskeringpumpar

Bakgrunden till detta examensarbete är ett behov av att införa vibrationsmätning i form av ett tillståndsbaserat underhåll vid AB Sandvik Coromants produktionsanläggning i Gimo. Underhållsarbetet på AB Sandvik Coromant i Gimo bedrivdes vid tidpunkten för studien som avhjälpande och förebyggande med olika fasta underhållsintervaller. Att införa tillståndsbaserat underhåll skulle kunna reducera kostnaderna, samt medföra en ökad uppföljning av varje maskin i form av hälsotillstånd. Målsättningen med examensarbetet var att utvärdera vibrationer som mätmetod. Arbetet har innefattat fyra, huvudsakliga moment.

Kostnadseffektiv svaveldioxidreduktion : en studie där ett optimalt svenskt mål jämförs med ett internationellt mål

In Sweden the work of reducing acidification and its prime cause; emission and deposition of sulphur dioxide, has been going on for decades. Despite of all the work that has been done the positive progress in the acidified areas is slow. This is partly due to a long recovery time for the acidified areas but also because the reductions of emission and deposition of sulphur dioxide have not been large enough. Emissions of sulphur dioxide from land based source in Sweden are estimated to 34 000 tons in the year of 2010. During the same year, approximately 182 000 tons of sulphur dioxide will be deposited over the Swedish territory.

Perimeter

The project explores the possibilities of using additive manufacturing (3d-printing) to build architecture. Through a combination of theoretical research and practical experiments a building system has been developed which has the capabilities to create houses with great geometric flexibilities to a affordable price today. The construction system Perimeter is demonstrated in a pavilion situated at Norra Djurgården in Stockholm. .

Enkla kemiska processer inom förskolan : En kvalitativ intervjustudie om förskollärares uppfattningar och tankar om läroplansmålet enkla kemiska processer

The aim of this study was to investigate preschool teacher?s perceptions about the curriculum goal concerning simple chemical processes. The result was based on narratives received by a qualitative study and semi-structured interviews of six preschool teachers. The results of the study showed that preschool teachers perceive that they actually are working in a relatively small scale with simple chemical processes and they do not really know what simple chemical processes are, and do not feel very familiar with the subject. Water, dough, mud, paint and baking were the most common activities that were used when working towards the curricular goal. However, it was never explained to the children that it was simple chemical processes they were working with during the activities, neither was it discussed among colleagues because of the uncertainty about the concept.

Optimering av blekeriet i CTMP-linjen vid Rottneros Bruk

At Rottneros pulp mill mechanical pulp is bleached with hydrogen peroxide. The changes of bleaching chemicals that are used for different grades are taken from bleaching tables; however these tables are old and need to be updated. The purpose of this thesis was to be the basis of new documentation.In this thesis three pulps where studied with the aim to find the optimal bleaching chemical changes (total NaOH/VP-quote) for each pulp. The pulps were taken from the filter before the bleaching tower and the pulps were bleached in the lab. The most important pulp property in this study was the brightness and how that was influenced by the chemical dosages.

Kloridhalter i gran utmed en depositionsgradient för havssalter :

The knowledge of the chloride content and its fluxes and patterns in trees is insufficient. Increased knowledge would be desirable, one of many reasons is to be able to more efficiently meet the problems that the substance causes in the pulp industry. The purpose of this study was to examine and describe the chloride concentration of Norwegian spruce (Picea abies L. Karst.) in the south of Sweden. Furthermore the aim was to be able to predict chloride concentration from readily measurable site factors.

Förbättrad planeringspolicy mot lågfrekventa beläggningsprocesser : - I en av Sandviks produktionsenheter

Att ha en god planeringspolicy för samtliga produktionsavsnitt i en produktionsanläggning är en viktig del i en organisation. Inom en industri med många produktvariationer och artiklar är det lämpligt att anpassa flera planeringsmetoder för effektiv planering mot samtliga operationer. I en av Sandviks produktionsenheter för skärtillverkning i Gimo var fokus riktat till att förbättra planeringspolicyn mot lågfrekventa beläggningsprocesser. I denna studie presenterar och optimeras planeringen mot två beläggningstyper vardera inom Physical Vapor Deposition (PVD) och Chemical Vapor Deposition (CVD). I grund för detta examensarbete finns en teoretisk studie, simulering samt fallstudier på Sandvik Coromant AB.

Påverkar jordbruk flödet av akvatiska insekter till land? : Effekter av jordbruk på akvatiskt tillflöde till land vid norrländska bäckar

Streams and riparian zone are closely linked by reciprocal flows of energy and nutrients. A large part of the transportation from water to land is in form of emerged aquatic insects. Conversion of land from forest to agriculture can greatly affect aquatic ecosystems, and due to the close link, also affect the adjacent terrestral zone. Investigating how the presence of agriculture in the surrounding area affects amounts of emergent aquatic insects gives an indication on how agriculture, in turn, may affect the terrestral enviroment. The study was preformed alongside ten streams in northern Sweden; five in landscape transformed by agriculture and five in undisturbed forest areas.

Avlivning av häst : en enkätstudie

Today there are various methods to use when euthanizing horses. Earlier the use of free or captive bullet was the most common method, but in recent decades this has changed and chemical euthanasia is now considered the most common method. The chemical euthanasia has in Sweden been dominated by the use of barbiturates. Somulose® entered the market in the beginning of the 90?s as an alternative to previous chemical euthanasia.

Uppgradering av biogas i systemperspektiv med avseende på miljöpåverkan och kostnader

Swedish biogas is currently produced mainly by anaerobic digestion of sewage sludgeat sewage treatment plants, landfills and anaerobic digestion of household or industrialwaste. Also cattle ma-nure from farms can be used to produce biogas. Upgradingbiogas represents an increase in methane concentration from about 65 % to about 97%. In addition, particles and contaminants must be sepa-rated from the upgradedbiogas. There are various methods for upgrading and this report compares sixdifferent methods with respect to environment and economy: water scrubber,Biosling, cryo technology, chemical absorption, Pressure Swing Adsorption (PSA) andmembrane separation.According to the used ORWARE model, chemical adsorption with amine has the leastenvironmen-tal impact (methane emissions) and the lowest costs.

Miljöfarliga transporter till sjöss : Kartläggning och riskanalys

An increasing number of chemicals are being transported by ships along the Swedish coastline. Many of these chemicals may pose a threat to the environment. Accidents and spills are luckily rare, but nonetheless it is important to be prepared for a possible chemical spill. The Swedish Coast Guard is responsible for responding to chemical spills at sea, and has both equipment and trained personnel for the purpose. In order to prepare for a possible accident one also needs to know what is currently being transported at sea.

Årstidsdynamik för kvicksilver i ett sövattensediment :

The limit for mercury in fish, set by health authorities, is exceeded in about half of the lakes in Sweden. Methyl mercury (MeHg) is the most toxic form of mercury and accumulates in fish. Therefore transformation of inorganic mercury (Hg) to methylmercury (MeHg) is an important process that we need to understand in order to possibly counteract the negative effects of mercury in the environment. The seasonal dynamics of mercury biogeochemistry is likely of great importance for the accumulation of MeHg in the aquatic food web. In thesis the chemical speciation and transformations of Hg and MeHg in bottom waters and sediments is followed in Ängessjön, a small lake located on the east coast in the middle of Sweden. The lake is not directly affected by any industrial pollution and concentrations of Hg in the sediment reflect the atmospheric deposition in this area, as well as processes taking place along the hydrological pathways from soil to lake. Samples from sediment, bottom- and streamwater were collected in average every second month during the period Feb.

Implementeringen av REACH : Fallstudie på ett SME-företag

The importance of chemical use is enormous for areas such as agriculture, industry and medicine and hence a prerequisite for our modern society. In order to protect humans and the environment from the negative effects of chemical use, chemical regulations have been used at a relatively early stage in our history. The purpose of REACH, the new chemical regulation of the European Union, is to generate new knowledge of chemicals within the European market and to increase the responsibilities of the enterprises when it comes to risk management. Whether the enterprises will implement the regulations or not will be of vital importance for the realization of the law?s intentions.The purpose of this study was to identify possibilities and problems that can occur when a downstream-user SME is about to implement REACH.

Variationer av klor, svavel och aska i havrekärna : odlingsfaktorernas inverkan på havrens bränsleegenskaper

The increasing oil prices during the last years have made it profitable to use cereal grains as a fuel. When compared with wood, cereals contain higher amounts of Cl, S and ash. The Cl and S content makes the gases from cereal combustion more corrosive than gases from wood combustion. The goal of this master thesis was to find out the variation of Cl, S and ash content for oat grain grown under different conditions. Oats was chosen because in Sweden it's considered as the cereal with the best fuel qualities.

Kvävestatus och risk för nitrifikation i två avverkade skogsområden i Halland

Nitrogen deposition leads to environmental damage in areas where the nitrogen deposition is high. Southwest Sweden receives an annual nitrogen deposition of up to 20 kg N/ha. Nitrogen that is not assimilated by the vegetation is accumulated in the soil, which may lead to nitrogen saturation and an elevated risk of nitrogen leaching. Nitrogen leaching from forest areas in southern Sweden has proven to be higher than from agricultural areas, which have been thought to be the main contributors to elevated nitrogen levels in rivers and lakes. The amount of nitrogen that leaches depends on the fraction of the total nitrogen in the soil that consists of nitrate, since nitrate is easily transported through the soil.

1 Nästa sida ->