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713 Uppsatser om Dynamic simulations - Sida 14 av 48
Direct-EGR tillämpat på HCCI
The Homogeneous Charge Compression Ignition (HCCI) engine is promising in terms of lowNOx, low particulates and high efficiency. Due to its homogeneous charge, where thecombustion starts almost simultaneously from a number of points in the combustion chamber,only lean mixtures are possible to burn because of the resulting rapid combustion, which is muchfaster than the combustion in an SI-engine or a diesel engine. When richer mixtures are used thecombustion will start earlier and also be more violent.To phase the combustion later and lower the combustion speed, external cooled EGR can beused. The EGR-system used in this thesis uses a divided exhaust channel where one channel andits corresponding valve are used only for transporting EGR back to the intake system.Consequently the EGR-valve is connected to the intake pressure. This system is called Direct-EGR (D-EGR).Engine tests verified that the CA50 indeed is phased later when cooled EGR is used.
Silverlight på Incordia AB
The purpose of this report is to outline the development of a dynamic Microsoft Silverlight application, which will be able to present products and be administered in a simple manner. The project has been carried out at Incordia AB, a company that specializes in e-commerce, situated in Helsingborg, Sweden. Although the Silverlight application is customized for a particular site, forMicro AB (an ongoing project at Incordia), the template and the classes that are used to manage information, are developed so that they can be used in future projects for Incordia AB..
Framtidens gymnasieskola - En styrning utifrån ett modernistiskt eller senmodernistiskt perspektiv?
This empirical work and base has been to analyze the new high school reform that the Swedish government introduced as a statement 2008/09:199 about: Higher demand and quality within the high school. This statement became legal through the government vote in spring 2010. But above all it is the investigation (SOU 2008:27) that is the central piece for these new examination changes for high school students that will come into effect 1 of July 2011. The purpose and questions asked in this analyze has been if the reform takes its base in a modernistic (traditional) way or a late modern scientific perspective. And also to find out how these new quality amendments in the investigation makes visible about the high school and what the purpose are about the changes. When scientific theories in these analyze is placed against the reform, the result shows that the modernization process reflects more of a late modern aspect, which constantly reappraise in a changeable society.
Hopfällbar hjullösning
In many products a compromise between ground clearance and the required space to store the product has to be made. This problem attracted the attention of the authors of this thesis.The objective of this project is to develop a functioning solution to a foldable wheel. The solution should be applicable to several types of product groups. A limitation for this work has been made so that the work only covers solutions for lighter vehicles.The purpose is to drive this project forward, so that a solution can be found. Furthermore the purpose of the report is to clarify how the authors proceeded to design and construct the wheel according to a fixed specification.
Modell och analysverktyg för beräkningav frekvensförlopp
The power system modelled in this thesis work has been developed for simulationwhen e.g. the production in some part of the power system is changed. The powersystem has been modelled according to the swing mass of the system, the frequencydependency of the load and the turbine governor. The model determines the systemfrequency, the period of regulation and the power exchange between the differentsubsystems in the Nordic synchronized system.In this model the system frequency is assumed to be the same in all different parts ofthe power system and the voltage conditions in the power system are neglected. Forthat reason power swings does not occur between different subsystems in the powersystem, which usually occur as a result of the swinging connection between thetransmissions line.
Bestämning av optimal fordonspark -Distribution av bitumen vid Nynäs AB
Nynas produces bitumen at two refineries in Sweden. The bitumen is shipped to seven depots along the swedish coast line, and from the depots special trucks handle the transportation to customers. Recently Nynas has transformed its supply chain and closed down a few depots. At the moment the company is considering a further reduction of the number of depots. In connection to these discussions an analyse of the companys distributionsystem and of possible changes is required.
Konstruktion av statorstomme för synkrongenerator : Förslag på design av statorstomme för användning i vertikalaxlade vindkraftverk
This thesis describes a conceptual design of a support frame for a synchronousgenerator used in a vertical axis wind power plant. In this system the generator isplaced on ground level. The thesis also considers the design of housing for thesupport frame and generator. The concept presented in this report is based on anearlier design. Besides geometric design, simplified simulations has been run in orderto optimize some of the parts included in the construction considering naturalfrequencies and structural strength.The result is presented as CAD-models andan assembly drawing..
CFD simulering av en fyrtakts Otto motorcykel motor
This thesis deals with the numerical 3D simulation of a four stroke, spark-ignited, internalcombustion engine, which is mounted on a high performance motorcycle. The work, carried outin collaboration with Politecnico di Milano and MV Agusta, focuses on the simulation of theintake, compression and expansion stroke, including combustion simulation, using an opensource CFD code.Simulation of internal combustion engines offers a great challenge in the field of CFD research.Moving boundaries of the solution domain, caused by the motion of the piston and valves, leadsto deformation of the computational grid, with decreasing quality of the solution as result. Basedon this, a previously developed mesh motion strategy was employed where a number of meshesare used to cover the whole simulation cycle. Within each mesh interval the internal cell pointsof the mesh are moved to account for the boundary motion of the piston and valves. This strategywas previously applied to simplified geometries as well as real engine geometries.
Vätskekopplade värme- och kylåtervinningssystem Utveckling av ett verktyg för energiberäkningar
According to a decision of the European Commission, measures are to be taken to reduce the use of energy in the EU. The goal is to reduce it by 20 % compared to the current use. This shall be done to the year 2020 (European Commission, 2011). One industry that use large amounts of energy is the construction of buildings which account for almost a third of the energy use (Brogren, 2012). The major part of the energy that is used in the construction industry is not used when the buildings are built, but rather during the rest of their subsequent lifetime.
Metoder för lastprioritering i fjärrvärmecentraler
A problem in the field of district heating is the oil burners needed to provide power when a peak load occurs. One possible way of reducing the needed amount of oil is to reduce the power demand for space heating in the district-heating substations when the need for district heating water exceeds a certain limit. This can be done by use of a locally working controller function.In this Thesis the options concerning load priority are evaluated. To evaluate the potential for using controller functions concerning peak load priority an experiment was brought out in a chosen district-heating substation. The impact on the indoor thermal comfort during a heat reduction was also taken into account.
Bildrendering med intermodulerat Atomkraftmikroskop
Intermodulated force microscope (ImAFM) is a type of dynamic AFM. ImAFM opens up possibilities for mapping the topography and making quantitative determinations of material parameters at the same time. With increased information the need to generate more informative images of the sample emerges. In this Bachelor's degree project I have created tools for rendering images of a sample. The topography is plotted as the height and a material parameter is color coded on topography.
Identifiering av stelkroppsmodell för industrirobot
In this masters thesis we consider a method for experimental identification of the inertial parameters of an industrial robot, using measured torques and joint angles. A dynamic model of the first three joints of the robot has been identified.To achieve good identification results, it is important to carefully choose the trajectory for the experimental identification. A method to generate trajectories using two suggested design criteria has been used and evaluated using an ABB industrial robot, and one of them yields good identification results..
Uttag av kvalitetsvirke a björk - potential och problem
The purpose of this report is to illustrate potentials and problems with withdrawal of quality timber of birch. The purpose is also to describe possible ways to increase available quantities of quality timber. Former research is reviewed as introduction. The study begins with a prognosis of future volumes of birch timber based on consequence analyze by Swedish Forestry Agency. To illustrate the importance of active maintenance, two stands are estimated and simulated in the Heureka module StandWise.
Säkra lån utan säkerhet : En studie av mekanismerna bakom utlåning i utvecklingsländer
I denna uppsats undersöks hur moral hazard påverkas i grupplån vid frånvaro av sociala band, övervakning, och kontinuerliga krediter. Undersökningen förklarar grupplån i teori men presenterar även empiriskt material från andra författares artiklar. Undersökningen visar att de sociala banden inte har den avgörande betydelsen som teorin förutsätter. Vidare konstateras att nära övervakning och låntagarens behov av framtida lån har stor betydelse för att reducera moral hazard..
Modellering av en panna med rörlig rost :
The aim of this master thesis was to create a dynamic model for the processes in a solid fuel boiler of the moving grate type. Another aim with the model was to keep it as simple as possible but still able to catch the dynamics of the processes in the bedplate of the boiler. The creation of the model had its origin from drying and combustion equations used in earlier modeling work of boilers. The represented model has been used to simulate different kinds of disturbances in a boiler and different ways to control the boiler. These tests show that controlling a number of parameters in the bed of the boiler is an effective way to keep the grate stable during disturbances.