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713 Uppsatser om Dynamic simulations - Sida 28 av 48

Utveckling av en Multi-Zonsmodell för NOx Bildning i Diesel Motorer

This thesis work is the last part of the Master of Science education inmechanical engineering at KTH, Stockholm.The aim of this project was the development of a Multi-zone modelfor NOxformation in Diesel engines. Because of the stringent emissionlegislations, great effort is made to decrease the fuel consumption and theharmful emissions of internal combustion engines. Computer simulationsplay a decisive role in this context because they substitute the expensiveand time-consuming laboratory tests.The model is based on a multi-zone approach and uses the wellknownExtended Zeldovich Mechanism which gives a relation to calculatethe NO formation rate using the concentration of different gas speciesinvolved in the process.All the most important phenomena involved in the Diesel combustionhave been modelled. A special attention is then paid to the equilibriumconcentration calculation; this is a significant part of the model whichstrongly influences the following steps.A Simulink model has also been developed. This second version isbased on the previous model and it is made especially to allow theconnection with other external softwares, GT-power in this case.

Sammankoppling av fjärrvärmenäten i Nyköping och Oxelösund : miljö- och systemkonsekvenser

District heating covers most of the residential areas and industries in the twoneighbouring Swedish municipalities Nyköping and Oxelösund. In Nyköping,Vattenfall AB Värme produces heat in a bio-fuelled CHP plant. In Oxelösund,waste heat and use of waste gases from the steel production at SSABOxelösund is the basis in the district heating system.This report examines the environmental consequences of a connection betweenthe two district heating systems. A broad system approach is used and the focusis on environmental effects in the system.A system analysis has been performed on the result of simulations of differentheat and electricity production alternatives. The alternatives simulated wereone where Vattenfall Nyköping covers the base load in the joint district heatingsystem and two where the power plant at SSAB Oxelösund supplies the heatbase load.The conclusion in this report is that the consequences of connecting the twodistrict heating systems can be both positive and negative, depending onsystem boundaries and on the environmental focus.

Konkurrensklausuler i anställningsavtal : En rättsdogmatisk studie

 This essay aim to clear the regulations that adjusts the use of non-compete clauses in contracts of employement. The historical developement shows tendencies that more employees have contracts that includes non-compete clauses. This developement does not always correspond with what is allowed concerning these clauses. Non-compete clauses is adjusted by the regulations in the collective agreement known as the agreement of 1969. The agreement has also been accepted outside its regular field of application.

Implementering av en PSS i Trängslets kraftstation

The purpose of this master thesis is to implement and validate a Power System Stabilizer (PSS) to a generator at Trängslet hydropower station in Dalarna, Sweden. Problems with local rotor oscillations can occur at the hydropower station when power is transferred on a new power line (130 kV) from Northern to Southern part of Dalarna. To ensure good operation properties on this power line Fortum Generation AB and Fortum Distribution AB wants to activate a PSS on a generator.There have been investigations in which situations and what equipment that contributes to rotor oscillations. When this is known the PSS is tuned to damp these oscillations by choosing a good set of parameters. The most important parameters for good performance are to choose amount of gain and phase compensation.

Elektrisk servostyrning för fyrhjulingar

This thesis is a feasibility study for a future product development project. The purpose ofthis project is to evaluate the possibilities and difficulties associated with the design of anelectric power assist servo for all terrain vehicles (ATVs). The project has been carriedout in collaboration with Nira Control AB. Nira designs and manufactures electric andelectro mechanic products mainly for the motor sport market segment.Nira Control AB is developing a fuel injection system for a new line of large ATVs oncommission. To be able to compete with manufacturers like Yamaha and Honda thecommissioner should be able to offer optional power assist steering.

Självmord : en kunskapsöversikt

The aim of this essay is to try to gain understanding and to get a more profound knowledge of suicide. The questions at issue were 1) What empirical factors are mentioned in the research as possible to explain suicide. 2) Which theoretical perspectives are discussed in research concerning suicide. To answer our questions at issue we carried out a selective research overview with a qualitative perspective. The primary documents that has been the foundation of this essay is constituted by nine of the leading researchers publications in the area of suicidology.

Ella Matematik - Internetbaserat läromedel för grundskolans matematikundervisning

Ella Mathematics is a web portal that will completely replace the printed math text book in the Swedish elementary school. When the math education is moved in to the digital world the flexibility and adaptability will increase.In 2011 the Swedish government revised the Swedish school system, which contained a whole new curriculum for the elementary school math education. This has been the foundation for the development of Ella Mathematics and the design of the three different users; student, teacher and parent. The development has been done with Dynamic Product Development methods from the project start in September 2011 until the final exam in May 2012.Ella Mathematics has been developed with the pupil?s math knowledge in focus.

Tillbakablickande nationalism ett minne blott? En teorikritisk fallstudie om nationalism och identitet i Hong Kong

In this thesis I have criticized traditional nationalism theories formulated by Eric Hobsbawm, Ernest Gellner, Benedict Anderson and Anthony D. Smith. The critique has been based on my belief that nationalism theories do not explain nations whose foundation is built on forward-looking, dynamic aspects such as economy, human and civil rights, and democracy. Traditional nationalism theories have been focused on historicizing perspectives whereas I want to draw attention to non-historicizing perspectives within the field of research. So far nationalism theories has had a shared past or a shared ethnicity as its focal point.

Energieffektivisering i flerbostadshus för studentboende

Uppsalahem AB is a municipally owned real estate concern that owns and administrates housing for nearly 30 000 people. The company puts a lot of effort into reducing the energy use of their housing stock. This project is a master?s thesis in the energy systems programme at Uppsala University, carried out in collaboration with Uppsalahem. The aim of this thesis is to provide energy saving measures for fourteen student housing buildings in Uppsala, Sweden.

Acceptansgränsen för solceller i lågspänningsnät : Kan den ökas?

Microproduction, also called distributed generation, is something that has become more and more popular in the electric grid. Microproduction can however lead to unacceptable performance if several units are installed in the same low voltage network. It is therefore good to know a limit where the performance of the low voltage network becomes unacceptable based on given parameters. This limit is usually called hosting capacity.In this report the hosting capacity with respect to voltage and current have been studied in three low voltage networks which are located in Falu Elnäts concession area. This has been done by simulations in a GIS-program where critical times of the grid have been simulated.

Skadedjursbegränsare i horisontella avloppsrör

The purpose with this project was to invent a product that secures buildings sewersystems against rats. The problem was presented to us by a local building maintainer inHalmstad, who had experienced big problems with rats in his real estate. The project hasbeen carried out by Per Johansson, Robert Lidén and Niclas Nilsson under our ownauspices. We are primarily sponsored by AMLI Business Partner but also byInnvationsgruppen, Halmstad Fastighets AB and Anticimex.To be able to secure a whole building with only one product we came to the conclusionthat the product must be placed in the horizontal sewer pipe that connects with themunicipal sewer system. Our goal was to invent a product that prevent rats from passingand at the same time not affect the water flow.

Premiepensionens Marknadsrisk : En Monte Carlo-simulering av den allmänna pensionen

A reforming trend is captured showing that countries are shifting from defined benefit pension systems towards defined contribution systems. The reforms have been justified through predictions that the defined benefit systems will not manage to provide good enough pensions to members in the future. The newer defined contribution pension plans often include individual financial accounts where individuals have the possibility to choose how a part of their pension savings should be invested. Sweden was early to introduce such a system, which at the moment provides more than 800 funds to choose from. The aim of this thesis is to capture the market risk associated with these individual investments and does so by using Monte Carlo simulations for six selected pension funds.

Samspelseffekter vid kapacitetsförbättringar. : Exempel från Dalabanan.

The trend in the transport sector is moving towards eco-friendly, fast and convenient transportation,this results in higher demands on railway transports. To meet the demand and quality requirements,the Swedish railway network will have to expand. The cheapest way is to expand little by little butwhat impact do these small steps actually have on the capacity?This thesis examines the interactions of different improvement for the capacity on a single-trackrailway. Through simulations in the software tool RailSys this report studies what effect block signals,extra meeting stations and rebuilding existing two track passing loops to three track loops have onthe capacity.

Implementering av höghastighetsgränssnitt i 0,15 µm halvledarprocess

This study investigated the possibility of implementing three standards, Transistion Minimized Differential Signaling (TMDS) and two versions of Stub Series Terminated Logic (SSTL), for inter-chip communication in a specific manufacturing process. The two SSTL standards were implemented in one transceiver system while TMDS was implemented in a separate system. The evaluation was done with Spice simulations on schematic level with some parasitic capacitance and resistance. The idea was to investigate the possibility of implementing these standards and get an idea of eventual shortcomings. In order to create models as a basis for evaluation, simulation environments with models for circuit board and packages were created and transmitters and receivers were designed.

Att leva är att känna - en pilotstudie i affektfokuserad terapi för unga vuxna

Varumärken inom B2B börjar få allt större uppmärksamhet bland forskare och företag i takt med att det uppmärksammats att varumärken har betydelse inom B2B-kontexter. Varumärket är ett av få sätt att differentiera sig på konkurrensintensiva marknader och kan medföra fördelar som en ökad kundlojalitet, premiumpriser och en ökad möjlighet att nå nya marknader. Samtidigt är forskningen om hur företag inom B2B bygger varumärken begränsad. B2B-marknader kännetecknas inte av produkterna utan av köparna som inte uteslutande är vinstrivande företag utan även kommuner, institutioner och icke- vinstrivande organisationer.I följande studie studeras underleverantörer vilka kännetecknas av dess förmåga att producera varor och tjänster till förmån för en köpare och dennes specifikationer. För en underleverantör är den grundläggande rollen att vara en värdeförmedlare som underlättar kundernas värdeskapande.

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