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370 Uppsatser om Numerical simulations - Sida 23 av 25

Konstruktion av värmespridare med grafit för flygelektronik

This master thesis was carried out for Saab Avitronics, a business unit of Saab ABactive in electronic systems for military aircrafts. Reliability and weight are of crucialimportance in this environment. To improve reliability and lower the weight graphitemay be used for electronics cooling. Graphite is an anisotropic material and hasthereof high thermal conductivity in two directions (in-plane) and a relatively lowconductivity in the third direction (through thickness).The purpose of this thesis was to investigate if graphite is an adequate thermalconductor to use in PCB carriers. The carriers support and cool the PCB by divertingthe heat dissipation from the PCB components to the edge.

Kombinerat system för ventilation och rumsuppvärmning : Parameterundersökning i simuleringsmodell för takvärmesystem

A large amount of our time is spent indoors in an artificial climate. To make the experience pleasant there are requirements on the ventilation and the heating system. At the present time the most common form of heating is a radiator system complemented with a ventilation system. A ceiling heating system with combined heating and ventilation can replace the two separated systems. The benefit with a ceiling heating solution is that it saves space since the radiator system is no longer needed.

Effektivisering av Bärarelagets arbetsprocess.

Syftet med denna rapport är att noggrant redogöra för och analysera de fråge-ställningar som satts upp och samtidigt beskriva utvecklingsarbetet av ett datoriserat system för att hantera bokningar och för SMS-notifiering.De frågeställningar som, i denna rapport, besvaras är:1. Går det att skapa ett datoriserat bokningssystem som bidrar till att Bärarelagets arbetsprocess effektiviseras men som samtidigt är lätt att lära för användare med liten eller ingen datorvana?2. Går det att vidareutveckla det som redan gjorts för att besvara frågeställning 1?Bärarelaget är ett företag som specialiserat sig på kompetensuthyrning där mobilkranar, kranbilar och truckar behövs.

Termisk hantering av litium-jon- batterier i elektriska drivsystem

The automotive market is currently undergoing a historical change where stricter emission legislations and ever increasing fuel costs have intensified the search for effective alternatives to the conventional internal combustion engine, which has resulted in a substantial trend towards electrification of powertrains. Storage of electrical energy is the fundamental component in this technology where the lithium-ion batteries are currently considered as the most appropriate solution. Lithium-ion batteries, however, as other types of batteries, can only be used efficiently and durably within a specific temperature range.This Master thesis has been carried out in collaboration with Electroengine in Sweden AB, situated in Uppsala, which has an ongoing project regarding development of a modular battery system for electric powertrains. The project is at a stage where an initial prototype has been developed which provides the foundation for this thesis. The study has addressed the battery system performance from a thermal perspective, in order to validate the ability of the system to create a thermally serviceable environment for the lithium-ion battery cells.

COMSOL Multiphysics - Ett energitekniskt analysverktyg vid numerisk simulering av köldbryggor och analys av fukt i konstruktionesdetaljer

Berggren, O. (2014) COMSOL Multiphysics ? Ett energitekniskt analysverktyg vid numerisk simulering av köldbryggor och analys av fukt i konstruktionsdetaljer. Examensuppsats i ämnet energiteknik. Institutionen för tillämpad elektronik och fysik vid Umeå Universitet.Konsultföretaget Tyréns har vid sitt kontor i Umeå önskat att utvärdera tillämpningen av programvaran COMSOL Multiphysics.

TRIM : ? Metod för att identifiera risker och uppskatta projekttider

ITT Flygt is a world leading company that mainly manufactures submersible pumps. A problem of ITT Flygt is that product development projects rarely manage to hold the estimated project time. It shows that something unexpected occurs in projects quite often, which results in delays. The delays can both be due to an optimistic time plan of projects and risks in product development projects which are not discovered at an early stage. This added with unforeseen delays makes it difficult for ITT Flygt to estimate the duration of their projects.The goal with the Master thesis is to examine a suitable method for simulation of project time.

Värmeöverföring i bergvärmesystem : En numerisk analys av den ringformade koaxiala borrhålsvärmeväxlaren

The borehole heat exchangers of today suffer from poor thermal and hydrodynamic performance. The purpose of this thesis is to improve the performance of ground source heat pump systems and thermal energy storages by increasing the energy efficiency of the borehole heat exchangers. For this reason, the annular coaxial borehole heat exchanger (CBHE) has been analyzed. This type of heat exchanger is interesting in terms of both thermal and hydrodynamic performance. A model has been set up in the program Comsol Multiphysics in order to investigate the heat transfer characteristics along the borehole.

Föroreningstransport i grundvatten : En modelljämförelse

This thesis compares different methods for risk assessment of a creosote contaminated site in Vansbro, Dalarna. In a complementary study the importance of using representative data for calibration and validation of stationary groundwater models is discussed. The time dependency between surface water levels and groundwater levels on the site in Vansbro is evaluated by step response analysis. The results show that the groundwater levels reflect only long-term variation in the surface water levels. Hence the use of such long-term means for calibration and validation of the stationary groundwater models is the only theoretically defendable alternative.As a first step in the comparison of risk assessment methods the degree of contamination is evaluated on the basis of generic guideline values for contaminated soils, developed by the Swedish Environmental Protection Agency.

Simuleringsmodell över Ålö AB

During year 2004 Ålö AB made significant change in their production process. The production of front loaders is nowadays highly automated with short operation times. To be able to control their process in a better way Ålö recently decided that they needed a tool for simulation of their production and to shift patterns. This final thesis started with a pilot study in Ålö?s factory in Brännland.

Gruppen som pedagogiskt redskap : En studie om gruppstorlekens pedagogiska betydelse i undervisningen.

The focus of this thesis is the group as a pedagogical tool. It investigates whether and how what is known of group size can help further schools in fulfilling knowledge and democracy goals and moreover how such knowledge can influence the principals? management. The mission of school education is to provide the basis for each pupil?s individual development and in the end it is pupils? individual performances which are graded.

Konstruktionstudie av en ångexpander

This thesis applies to a novel steam expander, one part of a steam engine system, a wobble plateengine. The piston in the expander moves axially with the outgoing rotating shaft and is locatedon a plate, why the engine type is called axial engine. When steam is applied to the plungers theplate wobbles creating a rotation on the shaft going thru the wobble plate. The steam expander issupposed to be used in exhaust gas recovery (bottoming cycle) applications and small scaleenergy production. The commissioner is Ranotor Utveckling AB.

Jämförelse av effekter från gruppträning i bassäng med landträning hos patienter med knäartros : Utvärdering av effekter på smärta, funktion i det dagliga livet och fritid- och idrottsaktiviteter

AbstractAimThe aim of the pilot study was to compare short- and long-term effects from group exercise in water with land-based exercise on pain at rest and pain with movement, along with the effects on function in daily life and practice of sports and leisure activities in patients with knee osteoarthritis. The aims were: Is there a difference in short- and long-term effects on pain intensity at rest and pain with movement after exercise in water or land in patients with knee osteoarthritis? Is there a correlation between the degree of pain intensity at rest and with movement, respectively and long-term effects from the two different exercises on function in daily life and practice of sports and leisure? MethodThe study was a randomized intervention study without a control group. Twenty patients with radiographic knee osteoarthritis were under a total of eight weeks treated with either land- or water-based exercise lead by a physiotherapist. The patients rated pain intensity at rest and with movement on a numerical rating scale (NRS) before and after the first training session, before and after the eighth training session, before and after the fifteenth training session and before the last and sixteenth training session.

Mekanisk integration av en IR-detektor i en Stirlingkylare

The master thesis ?Mechanical Integration of an IR-detector in a Micro Cooler? has beenperformed at FLIR Systems AB in Danderyd. FLIR Systems is a world leader in the design,manufacture and marketing of thermal imaging camera systems.The thesis project is divided into to two areas, Production Method and Noise.The Production Method concerns the positioning of a detector on the cold finger within the IRcamera.The detector has to be positiond with very high accuracy at the center of the cold finger,so it can be placed in line with the optical axis to avoid movement of the picture during zooming.The positioning of the detector is at present done with the help of specially designed guides on aplate on top of the cold finger. The design workes well but the special machining needed for thisplate is very expensive.The goal concerning the production method was to derive a new more cost effective method forthe assembling and positioning of the detector on the cold finger by replacing the guides on theplate with a reusable equipment or some other alignement operation.Several concept ideas have been generated with the help of concept generation methods in theform of concept classification trees and concept combinational tables. Two of these conceptswere selected to be further refined.

Lane Keeping Aid : ett förarstödjande system för bilar

Many traffic incidents are due to the driver?s lack of attention, resulting in dangerous lane departures, either sliding off theroad or into the oppose lane. These kinds of incidents often have serious outcomes, which has led to much effort being concentrated on preventing or lessening the damages when the incident is already a fact, for example by installing safety belts and air bags. These measures may be considered to be acts of so-called passive safety. Active safety on the other hand, means that the safety systems intervene before the incidents have occurred.

Utvärdering av en väggkonstruktion utan PE-folie : Med en undersökning av hårdvaxolja som diffusions-/konvektionsspärr

District heating covers around 80 % of the heating demand in apartment buildings and 10 % in single-family homes in Sweden. In the year 2010 the total input of energy to the Swedish district heating grids was about 70 TWh, which corresponds to 11 % of the total energy input to the whole energy system in the country. Through the combined production of heat and power the CHP-plants often reaches an efficiency of 90 % from energy in the fuel to produced heat and power. In order to keep the efficiency high it is important for the owners of the plant to have good knowledge about the plants performance at different operation points. Strängnäs Energi AB initiated this diploma work together with FVB Sverige ab in order to come up with a program for short term planning of the production of heat and power at the company´s CHP-plant.The work consists of three main parts.

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