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1345 Uppsatser om Flow simulation - Sida 59 av 90

Studie av belagda kolvringarmot plasmasprutat cylinderfoder : Med avseende på friktion och nötningsmotstånd

Future emission legislation puts great emphasis on increasing the efficiency of the engine, thereby reducing fuel consumption. The tribological contact between cylinder liner and piston ring is where an great amount of energy is lost due to friction, and by reducing these losses an reduction in fuel consumption can be achieved.The aim of this thesis was to evaluate the tested piston ring coatings against a plasma sprayed cylinder liner and rank these combinations of materials for friction and wear resistance. The coatings that were tested was Cr + Al2O3, (Al,Cr)N, two types of CrN and WC / C.The experimental tests were performed with a so-called pin-plate, where used oil with addition of an acidic mixture of sulfuric and nitric acid to mimic the acidic condensate formed when exhausts recirculate, were added with a continuous flow. The results were then analyzed by weighing, studies by optical microscopy and scanning electron microscopy (SEM) and profile measurements.The results from each material combination were that the plasma coated cylinder liner wears too aggressively in order to yield a ranking of the piston ring coatings based on the parameters of friction and wear resistance. It is therefore proposed that an alternative coating on the cylinder liner should be developed, lacking the large abrasive wear on piston rings and that can withstand the corrosive environment resulting in engines equipped with EGR.

De svenska fastighetsbolagens redovisningsval för förvaltningsfastigheter och dess effekter på redovisningens kvalitativa egenskaper : En studie av noterade respektive onoterade svenska fastighetsbolag efter implementeringen av internationellt regelverk

AbstractTitle: The Swedish real estate companies choices of valuation within investment properties and its further effects on the qualitative characteristics of accounting.-A study of the Swedish real estate companies listed and non - listed on the stock market, after the application of the international rule board.Background and Problem: From January 2005, all companies, listed on a stock market within the European Union, are required to prepare their consolidated accounts using common set of International Accounting Standards, IAS/IFRS. In Sweden, this opportunity has also been given to non-listed companies, to voluntary implement these rules in their consolidated accounts. One difference between Swedish accounting rules and contemporary International rules, deals with the accounting treatment of investment properties, which foremost affects the real estate market?s accounts. In contrast to the Swedish Financial Accounting Standards Council?s recommendation RR 24, the new standard, IAS 40, permits a choice between different accounting alternatives.

Att leta bänkbok: bänkbokspraktiker i skolbiblioteket.

The purpose of this Master's thesis is to contribute to a betterunderstanding of children's free time reading book practices by studyingpupils in the school library and their processes of finding and borrowingbooks for themselves to read silently in the classroom, so called free timereading books. The study also includes observations of the staff's role,particularly the school librarian's in supporting pupil's book selection.The empirical material consists of field notes from an etnographic studywhere pupils in 4th grade (aged 10-11) and staff were observed duringthree school library visits. The theoretical framework is inspired byLennart Björneborn's concepts of information practices in libraries:serendipity, integrative library interface, mediation flow and affordancespaces.The study shows that pupils' search for free time reading books in theschool library is relatively routine-based at the same time as it isspontaneous. The process is an interplay with factors such as time,display and interaction in the integrative library interface. In the presenceof adults, finding books becomes an imposed task for the pupils.

En studie om lärares arbete vid övergångar : Hur arbetet som bedrivs i arbetslaget återspeglas på individ, grupp och organisation

 This thesis is based upon the assumption that in Swedish school today it is a wide gap regarding the information flow when pupils are switching school. This was one of the reasons Skolverket published a report clearly stating that this is the case. The purpose of this thesis is to examine and describe how teachers are working in a teacher team at transitions to see and understand what their work may mean individually, in a group and to the school as an organisation. The questions at issue is to see how the teachers cooperate during transitions and how they notice students in need of extra support and students level of knowledge during transitions. The two last questions at issue is first to see how teachers approach parent?s expectations on the school and the teachers, secondly it is to examine what implications their work will have on the school.

Simuleringsprogram som verktyg vid projektering av solvärme

The government regulations for energy use in buildings will be tightened in the future. At the same time the interest in environmental classifications and certifications of buildings is increasing. This has meant a new situation for solar energy. The designs of solar heating systems are often based on experience and/or rules of thumb, rather than calculations and simulations. This thesis examines whether simulation tools, in this case Polysun, are useful in this work.

Jordfelssimulering och modell-validering med PSCAD av ett impedansjordat distributionsnät

Detta examensarbete har utförts hos Vattenfall Eldistribution på avdelningen Kontroll och Skydd med målsättningen att utforma och utvärdera en nätmodell avsedd för jordslutningssimuleringar i PSCAD. Ombyggnationen från luftledningar till markkablar har medfört att kapacitansen i distributionsnätet ökat, vilket ställer högre krav på jordfelsutrustning och på nätanalyser för att kunna försäkra att en säkerställd frånkoppling kan ske enligt de myndighetskrav som föreligger. Syftet med arbetet har varit att undersöka hur en nätmodell bör utformas för analys av stationära in-svängningsförlopp och utvärdera hur stor noggrannhet som kan förväntas gentemot verkliga jordfelsprov vid felresistanser på främst 3 k? och 5 k?. Nätmodellen har ut-formats efter ett verkligt impedansjordat mellanspänningsnät med ?-länkar i PSCAD och utifrån de nätuppgifter som förekommer i Vattenfalls näthanteringsprogram Netbas.

Dimensionering av betongplatta på lös undergrund. En jämförelse mellan tre beräkningsprogram

Today more effective computer programs are in use, regarding design of geotechnicalconstructions. There is a risk that the theoretical background of the computerprograms, its limitations and the signification of the choice of soil parameter isforgotten when the computer programs become more user-friendly.This Master thesis deals with simulation and analysis regarding three computerprograms, FEM-design, with the addition Raft, Plaxis and BE-slab. Comparisons aremade for settlement and maximum moment in a concrete-plate. FEM-design is a threedimensional FEM-program, foremost created for design engineers. Plaxis is a twodimensional FEM-program, intended for geotechnical engineers while BE-Slab is aBoundary elements program in two dimensions that is mainly used by designengineers.

Provmetod för olje- och partikelöverdrag från kompressor till tryckluftssystem

Compressed air is an energy source that is widely used in today's trucks and buses.Compressor located next to the engine supplies the pneumatic system with the compressed air and is lubricated with the engine oil. Some of the oil follows the air flow in both liquid and solid phase. The solid phase, namely the carbon particles are created due to the high temperature in the compression chamber.Oil- and particles carryover softens and destroys the rubber material in the air valves and disturbs the mechanical function of various components in the pneumatic system. In order to reduce oil- and particles carryover is an Air Processing System (APS) set downstream the compressor.No method for establishment of oil- and particles carryover from the compressor exists at the moment. Therefore the filtration efficiency of APS is currently unknown.

En studie i lustfyllt lärande i år 5-6 om runor

Syftet med studien var att jag skulle få djupare kunskap om min egen undervisning och vad som påverkar elevers lärande, samtidigt som jag ställde mig frågorna vad som bidrar till ett lustfyllt lärande för eleverna, vad som påverkar undervisningen så att eleverna tycker det är roligt att lära sig och varför det blev mer lustfyllt och roligt att lära sig i arbetet om runor.Metoden jag använt mig av är av både kvalitativ karaktär, där jag själv har varit med som lärare i undersökningen, och kvantitativ karaktär, där ett resultat av elevernas svar har redovisats i en enkät. Undersökningen bygger på en dokumentation av ett arbetsområde om runor och en enkät utformad med 28 stycken s.k. skalfrågor.Resultatet av enkäten visar på att 91 % av eleverna var positiva till arbetet med runor vilket kunde bero på variationen i arbetssätt och metoder och att eleverna använt alla sinnen under tiden de arbetat om runor. Eleverna har arbetat både teoretiskt (55 % positiva) och praktiskt (98 % positiva) vilket visar på att eleverna har blivit tillgodosedda avseende sin individuella intelligens som Gardner (2000) menar varje människa har.Det har varit spännande och givande att studera ingående vad jag gjort och vilken effekt mitt handlande har givit. Det är inte ofta jag har tid att analysera och följa upp min undervisning på det sätt jag kunnat göra här.

Scenen är din: upplevelseproduktion som perspektiv vid kommunal rekrytering av unga medarbetare

I dagens upplevelsesamhälle sker en generationsväxling på svensk arbetsmarknad. En ny generation av unga medarbetare, som går under benämningen generation Y, ska ersätta 40-talisterna som går i pension. Arbetsgivare står inför en utmaning gällande rekrytering av dessa unga medarbetare som skiljer sig från tidigare generationer. (Fürth, 2008). De har växt upp i en tid då fokus har flyttats från materialistiska värden till emotionella sådana och där upplevelser har fått en ökad betydelse (Pine & Gilmore, 1999).

Värdepapperisering i Sverige : Finns det en marknad?

As of today, securitization is an established product on the capital market. The first transaction was made in the US in the 1970s. Since then the product has been developed and today there are several different structures of the product. Internationally securitization has been used for two reasons. Originally securitization was used to gain capital relief, but since capital requirements such as Basel II were implemented, the usage of securitization changed to more of a funding source.

vindkraftens påverkan på elkvaliten

This thesis concerns how the power quality in the grid is affected by the connection of wind power plants. As things are at present, Fortum Distribution AB has a number of wind turbines and wind parks connected to the own grid. As the pressure on building and connecting additional wind power is increasing, so is also the interest of how the already existing wind power generation affects the power quality in the nearby distribution grids. The study is performed by direction of Fortum Distribution AB and is limited to the 10 kV/40 kV-grid in Bohuslän, Sweden. The methods for calculation of power quality are compared to the results of a number of measurements.

#yogaeverydamnday : En analys av religiösa och andliga uttryck och beskrivningar på Instagram

In recent years, the Internet has exploded with different kinds of social media, where a significant function is to share your life in text and images. This changes how we form our identity, our religious identity included. The aim of this paper was to study how Instagram forms a space for the creation and development of religious and spiritual beliefs. For this purpose, Instagram updates from five women with yoga oriented Instagram accounts have been analyzed in relation to two theories: Paul Heelas? och Linda Woodhead?s theory of a spiritual revolution and Heidi Campbell?s theory of networked religion.The aim of the study was to explore how these women presented themselves in their Instagram flow and what part religion and spirituality had in their presentations.

Attityder hos råvaruleverantörer till ett sågverksföretag : en fallundersökning av leverantörer till J.G. Anderssons Söner AB i Kronobergs län

It has been even more important in the forest sector in recent years to look at the whole chain from suppliers to end users, to improve operations and improve performance and the profits of the company. The research and development have been concentrated on the buyer?s market and product development, probably because this research has capability to give an increased cash flow. But to obtain stability and continuity in the production and selling units, the suppliers should also be investigated. The aim of this thesis is to study a one company's existing suppliers of roundwood and investigate the differences and attitudes they have about the company offerings.

Vad tycker skogsägare om virkesinköpare och inköpsorganisationer? : utveckling av ett skogsbolags tjänster och köpverksamhet till privata skogsägare

The private forest owners play a key role in the supply of round wood to the Swedish forest industry. Today it is a keen competition between forest companies about the wood from private forest owners. In order to get access to the wood from the private forestry you need to be an attractive collaboration partner, who can offer long-term collaboration, service at top-level, and acting for good prices to the forest owners. This work aims at analysing the situation on the market today. It gives Sveaskog purchase department a good view of the forest owners? opinion in general about the existing purchase activities. Forestry service level and timber prices are determining factors for a successful relationship between forest company and forest owner.

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