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370 Uppsatser om Numerical simulations - Sida 9 av 25
Energikartläggning i Sundbybergs stad
The purpose of this thesis has been to develop a tool for modelling and simulating the nuclear plant Ringhals 3. The model should be used to improve the knowledge on the dynamics of the plant. Ringhals 3 is being upgraded to produce more power and a tool for analyzing the new operating conditions is needed.The work in this thesis has consisted of improving and developing an existing model of Ringhals 3 made with the modelling tool Dymola. The model has been validated by comparing the results of a simulated house load transient with data from the actual plant. Validation shows good agreement with data from the real plant.
Implementering av lean i ett gjuteri med låga volymer och hög variation
Valmets own foundry in Karlstad has during a long period of time had problems being profitable. The goal today is to turn this around. Today there are three different productionlines; engine blocks, Yankeecylinders and components for the wind turbine industry. This master thesis has focused on examining if value stream mapping is a useful tool to use in a foundry, and therefore outside the typical manufacturing industry. The target has also been to evaluate if there is a possibility to improve the flow in the foundry and also the results.During the 20 weeks this work has been done at the foundry data has been collected and analyzed.
Övervakning och detektering av sprickor i betong med en elektriskt ledande färg
The purpose of this thesis has been to develop a tool for modelling and simulating the nuclear plant Ringhals 3. The model should be used to improve the knowledge on the dynamics of the plant. Ringhals 3 is being upgraded to produce more power and a tool for analyzing the new operating conditions is needed.The work in this thesis has consisted of improving and developing an existing model of Ringhals 3 made with the modelling tool Dymola. The model has been validated by comparing the results of a simulated house load transient with data from the actual plant. Validation shows good agreement with data from the real plant.
Analys av beställarkrav vid upphandling av entreprenader
The purpose of this thesis has been to develop a tool for modelling and simulating the nuclear plant Ringhals 3. The model should be used to improve the knowledge on the dynamics of the plant. Ringhals 3 is being upgraded to produce more power and a tool for analyzing the new operating conditions is needed.The work in this thesis has consisted of improving and developing an existing model of Ringhals 3 made with the modelling tool Dymola. The model has been validated by comparing the results of a simulated house load transient with data from the actual plant. Validation shows good agreement with data from the real plant.
Utveckling av en HBV/PULS-model med sammanfogade markfuktighets- och responsrutiner
Soil properties affect the chemical composition of soil water. When studying transport of chemical substances through a basin, it is therefore important to know from which soil layer the main part of the runoff is generated. The aim of this study is to develop an HBV/PULSE model with merged soil moisture and response routines, which generates good approximations of groundwater levels. It should be possible to extend the model to simulate transport of substances and take into account which soil layer the groundwater level is currently in. The hydrological version of HBV/PULSE is used since there is no need to account for pH or alcalinity at this stage.
Orsaker och sammanhang kring avvikelser i processen med prefabricerat byggande
The purpose of this thesis has been to develop a tool for modelling and simulating the nuclear plant Ringhals 3. The model should be used to improve the knowledge on the dynamics of the plant. Ringhals 3 is being upgraded to produce more power and a tool for analyzing the new operating conditions is needed.The work in this thesis has consisted of improving and developing an existing model of Ringhals 3 made with the modelling tool Dymola. The model has been validated by comparing the results of a simulated house load transient with data from the actual plant. Validation shows good agreement with data from the real plant.
Åtkomststudie för robotiserad svetsning av flygmotordetalj
The aim of this thesis was to investigate if the robotized welding method FSW (Friction Stir Welding) could be applied for joining a rotating structure in an aero engine at Volvo Aero Corporation. FSW is expected to introduce less defects than today?s welding methods and could therefore be suitable for critical aero components. The material is the nickel based alloy Inconel 718, however a material experimentation is outside the scope of this report.The main goal of this study is to verify if the ESAB ROSIO robot based FSW-system has a suitable work space to be able to weld the rotating structure, and if the welding tool has accessibility to the joints. The FSW-process needs a rigid fixture, and a number of fix-ture concepts are presented based on a proposed weld sequence.
Mätning av Mikroläckage i Dentala Implantat
Osseointegrated titanium implants have become a commonly used method in edentulous jaws and today there are success rates in the magnitude of 82 % in the lower jaw and 98 % in the upper. During first year after implantation a fully normal marginal bone loss of 1-2 mm occurs. If the bone loss continues there is a risk of implant failure. High tensions in bone and inflammation caused by bacteria are possible reasons for this problem. It has been shown that a leakage of bacterias occurs between the parts of the implant and there are theories that this has effects on the marginal bone loss.
The aim of this thesis has been to increase the knowledge about microbial leakage with help of in vitro tests and virtual simulations.
Utvärdering och implementering av automatiska farthållare i fordonssimulator
Vehicle simulators are becoming more common in vehicle industries. Company earns lot of money on simulations instead of real tests. Real tests are necessary but not made so extensively as before.In this thesis the building of an vehice simulator will be described and a comparison between three different cruise controls. The three cruise controls are PI-regulator, a regulator who regulates after positions in the terrain and a MPC-regulator. The reason for choosing this three is to see the difference between simple regulation and more complex regulation with respect to fuel consumption, travel time and complexity.The vehicle simulator is made in Matlab/Simulink, Visual Studio and Open Scene Graph.
Modeller för studier av ursprungsmärkt el
The EU has decided that it should be possible for consumers to get information about the origin of the electricity they buy. Therefore, there is a need to examine different systems for electricity disclosure. In this thesis two ways of disclosure have been studied:? Certificate system. A certificate system involves two parallel markets, one for trading electrical energy and one for trading certificates of origin.? Separated Markets.
Leg SSk
Syftet med denna studie var att go?ra en bedo?mning av den postoperativa fo?rloppet i hemmet hos dagkirurgiska ljumskbra?cksopererade patienter. Data insamlade med hja?lp av ho?gstrukturerade telefonintervjuer. En enka?t med standardiserade fra?gor och ikryssbara svarsalternativ som kommer har anva?nts vid telefonintervjuerna.
Resultaten fra?n de 52 intervjuerna visade att de flesta patienter inte o?verskred Numerical Rating Scale (NRS) 3 i vila eller ro?relse dag ett.
Åsktransienter och överspänningar : En spänningsfylld simulering av elkraftsystemet vid Forsmark 3
A power system will inevitably be subjected to transient overvoltages, most often produced by switching operations and lightning strikes. These transient overvoltages may harm sensitive equipment without sufficient protection, but it is not an easy task to predict what transients may occur or how they affect the system. A fault occurred in a low voltage system at Forsmark 2012 and overvoltages from lightning were concluded as the probable cause. The three aims with this thesis are to develop and test a model of the power system at Forsmark 3, analyse the transient behaviour of the system when subjected to lightning surges and identify critical parameters, and lastly to provide a tool for investigating the protection of the system. The modelling and simulations were performed in the freely available simulation program LT Spice.
MEMS baserad referensoscillator
The interest in tiny wireless applications raises the demand for an integrated reference oscillator with the same performance as the macroscopic quartz crystal reference oscillators. The main challenge of the thesis is to prove that it is possible to build a MEMS based oscillator that approaches the accuracy level of existing quartz crystal oscillators. The MEMS resonator samples which Philips provides are measured and an equivalent electrical model is designed for them. This model is used in the simulations of the Pierce oscillator and the transresistance amplifier oscillator that are evaluated in this thesis. Finally the Pierce oscillator is implemented in the A BCD2 process and manufactured at Philips Semiconductors in Nijmegen, The Netherlands.
Skadliga nollflödespunkter i Fortum Värmes fjärrvärmenät i Stockholm : En analys av dess förekomst och effekter
When several production units provide a district heating network, water is pumped from different directions. When the flows from the plants finally meet in the network, the water can be completely still. These places are called zero flow zones. In district heating networks with several plants, which also have different supply temperatures, large and frequent temperature fluctuations can occur when the zero flow zones move. This may cause wear on the pipes, a phenomenon called low cycle fatigue.For this reason it is important to examine where and when zero flow zones that cause temperature changes occur.
Modellstudie av föroreningsretention i Bäckaslövs våtmark : Tillämpning av modellverktygen MIKE SHE WET och MIKE 21
During the nineties, ecological handling of urban storm water became very popular in Sweden. Together with Chalmers University of Technology and two Swedish communities, DHI Water and Environment has been doing research of storm water ponds and constructed wetlands. This thesis work is a part of that research project. The work has been applied at the Bäckaslöv storm water treatment plant in Växjö, Sweden. The plant consists of one storm water pond and a downstream constructed wetland.