AbstractIn urban societies people spend more and more time indoors, which put great demands on the indoor environment. If the ventilation is to manage the removal of unwanted substances in the indoor air, a good mixing of the air is required. The question arises that, whether the buoyancy forces will counteract a good mixing of the indoor air or not?This report aims to clear up the difficulties whether you need to consider the buoyancy forces or not, when adjusting a ventilation unit. For studying the indoor mixing of the air a two dimensional model is constructed in COMSOL Multiphysics.

Syftet med detta arbete är att simulera ett värmesystem i COMSOL Multiphysics, Pipe Flow Module, Non-Isothermal Pipe Flow som innehåller ekvationer och randvillkor för att modellera inkompressibel strömning och värmeöverföring i rör.Data om processen och dess komponenter har samlats in från industrin där arbetet är utfört och i vissa fall modifierats för att bättre beskrivas i programmet.Utifrån insamlad data har en modell byggts upp och två simuleringar har gjorts. En stationär för starten av systemet, den har sedan legat till grund för en dynamisk som simulerar förloppet från start till normaldrift.Tiden det tar för det aktuella fallet att nå drifttemperatur är 16 timmar. En felströmning upptäcktes samt att en av pumparna inte kommer att klara en start från 20 °C..

Expansion och förtätning av städer leder till att såväl areal som andel hårdgjord yta ökar i våra stadsmiljöer. Detta genererar en ökad dagvattenavrinning eftersom regnvattnet inte har samma möjlighet att infiltrera i naturmarker och grönområden. Den ökade mängden dagvatten riskerar att orsaka problem i områden där ledningsnätet dimensionerats för de dagvattenmängder som tidigare varit aktuella. Att utöka ledningsnätets kapacitet är ofta mycket kostsamt och det är därför önskvärt att istället minska belastningen på de befintliga systemen. En allt vanligare metod för detta är att byggnaders takyta bekläds med växter, så kallade gröna tak.

When protection zones for wells are delineated, it is important to acquire good knowledge about possible travel time from different points in the catchment area to the well. Often, simple analytical methods are used for estimating travel times and the assumption is made that the hydraulic conductivity is relatively homogenous within the aquifer. Nevertheless, many aquifers are strongly heterogeneous which may lead to differences between estimates and actual travel times. As a part of the process to develop improved methods for delineating protection zones for groundwater supply wells, a tracer experiment was performed in a glaciofluvial esker formation in Järlåsa. On the basis of the experiment, a numerical flow model was created for the test site.The purpose of this master?s thesis was to apply the flow model to an aquifer where the hydraulic conductivity shows great variability and should be described by a stochastic distribution.

The Volvo Trucks plant in Umeå is a highy complex manufacturing facility where the same production line handles a variety of different models. This require flexible and agile processes with high quality standards. This thesis studies the flow of material through a production line and how Volvo can use their existing manufacturing monitoring system to optimize the flow of materials.The goal with the thesis is to identify eventual problems with the flow of materials and to deliver a few proposals on how the production line can improve its productivity. The theory of LEAN, Just-In-Time and Supply Chain Management serves as the scientific reference to this project. By analyzing the flow of material, performing interviews and observing the processes a few problems are identified.

A patient simulator for testing anaesthesia machines has been developed at Maquet Critical Care AB, to reduce costly and time-consuming experiments on animals. The device simulates human lungs regarding lung dynamics and volume, uptake of anaesthetic agents and the production of carbon dioxide, heat and moisture. Further demands on the simulator are durability and size; the device shall be compact enough to be moveable.The resulting simulator fulfils the requirements and enables better repeatability and ability to test extreme cases than experiments on animals do.Uptake of the anaesthetic agent is achieved in a active carbon filter and controlled by regulating the flow. The flow is created by a regenerative blower and controlled using a proportional valve. The uptake can be set by the user or by a simple uptake model modified to recursively handle changes in the concentration of anaesthetic agent.Carbon dioxide is fed into the system from a tank by a mass flow regulator.

Due to increasing regulations regarding new diesel vehicles particulate matteremissions the new Scania truck, Scania Euro 6, has been equipped with a particulatefilter. This component effectively stores the particles in the exhaust gas but must becleaned in order to prevent itself from clogging. The filter is cleaned through aprocess named regeneration which is a thermodynamic process in which thetemperature of the filter is raised through fuel supplied to the exhaust gas.The purpose of this thesis is to contribute to the development of improved controlstrategies of the temperature during the regeneration process through thedevelopment of model-based controllers. These controllers are designed in order tohave good performance in stationary as well as automatic regeneration.In order to develop these model-based controllers a model of the system isconstructed. The model is described as a linear thermodynamic grey-box model withflow varying parameters, showing good results in validation.The model provides a simulation environment during the controller design, which isfocused around the development of linear regulators with the exhaust gas mass flowas a scheduling variable whose size determines controllers? mode of operation.

At the Women?s House in Örebro, a children?s project has started where the work method ?Oasen? [Oasis] model has been developed by two children?s educationists. The aim of this study is, with the ?Oasen? model as a starting point, to deepen the knowledge of (1) how to meet children?s central needs while staying at a Women?s House and (2) what the ?Oasen? model may contribute to the children. The theoretical framework consists of a cognitive approach to the progress of children experiencing domestic violence and a presentation of conceptions concerning children?s needs.

Hur kan svårighetsprogression användas i skapandet av Puzzlehunts med syfte att uppnå en ökad upplevd känsla av flow hos spelaren? Denna frågeställning behandlas i uppsatsen och problemet som måste lösas är hur man kan bygga upp en ackumulerad kunskap om något vars syfte är att hela tiden tvinga dig att hitta nya lösningar på problem. I mer traditionella spel kan upprepning lära spelaren hur spelmekaniken fungerar. I puzzlehunts kan upprepning av spelmekanik inte användas eftersom målet för varje pussel är att hitta mekaniken som löser problemet. Uppsatsen visar att man genom inlärning av hur man skall tänka för att hitta lösningarna till pusslen kan bygga upp en ackumulerad kunskap hos spelaren och därmed även ha en svårighetsprogression och öka upplevd nivå av flow hos spelaren..

Tidigare studier har visat att faktorerna KASAM, flow samt prestationsbehov har betydelse för hög upplevd arbetstillfredsställelse. I denna studie undersöks om dessa faktorer även är aktuella under svenska förhållanden. En enkätundersökning genomfördes på 137 anställda på tre olika företag för att mäta om de tre faktorerna kan predicera arbetstillfredsställelse. Resultatet visade att KASAM, och särskilt komponenten meningsfullhet, var en stark prediktor av arbets-tillfredsställelse. Även flow, och särskilt dimensionen inomboende arbetsmotivation, hade ett signifikant prediktionsvärde medan det visade sig att prestationsbehov inte predicerade arbetstillfredsställelse.

We were commissioned by Bulten Stainless AB to identify and analyze their customer order flow. Because the company had problems with delays in the production and deliveries to the customer, the task also included investigation of how the company work with prevention and management of delays. The purpose of the project also included to identify critical factors for effective order flow in smaller workshop companies.The information about the flow and how the work takes place within the company were collected through observations on the company and interviews with the staff. This information was used to draw maps over the customer order flow and to write a description of the current situation within the company. Both strengths and weaknesses of the companies work could be identified through analysis of the present situation.

Results have shown that flow batteries may be a solution in the future as an effective and environmental friendly method to an energy storage system (ESS). The technology is reliable and has a high efficiency that comes with low energy losses and a long lifetime. The range of possible fields is suitable for cutting energy peaks in the power grid, by always have a ready and available energy storage that balances the production. By comparing the advantages of flow batteries with conventional batteries it is mainly the fact that they can conserve energy for a long time without being self-discharged thanks to that the storage capacity is in principle endless and limited by the size of the electrolytes tanks that makes them a great energy storage system. The batteries won?t take any damage or decrease in performance when charging or discharging it or if you exhausts it to 100 % and leave it discharged for a long time.

For Skattkärr IF a turf field with warming has been projected to increase field?s utilization hours and to have a longer period for athletes to perform their activities outdoors. The technique chosen to heat the plan is a type of a geothermal heating system without a heat pump. The brine, which is water with 30% ethanol, collects heat from the borehole and discharges it to a coil in the field. There is at position 11 boreholes but it is planned to increase the number to 31, which is the design for the facility.

AbstractWith increasing population and increasing demands for comfort and thus an increase in energy demand, it is necessary to examine various energy-efficiency measures. This work deals with the ability to control the flow through the heating system to achieve the desired comfort with as little energy as possibleA heating system contains of different parts, roughly speaking, you can divide it to three main components: Heat source, Distribution and Heat emitters. All components are working together to bring heat to the building. What is examined in this report are different ways of adjusting the flow and supply temperature and how it affects comfort and energy use in a building.At today ?s date the conventional method is to use a high flow through the heating system, which affects pressure drop and cooling of the fluid.

The purpose with this masters thesis was to model the scanner in a system for laser bathymetry. The model was then used to develop a controller for the scanner so a good search pattern was achieved. Two different types of models have been tested, a physical model and a Black Box model of Box Jenkins type. The physical model has been derived from Lagranges equations. Identification experiments have been used to compute the Black Box model and to find the unknown parameters in the physical model.