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4841 Uppsatser om Water model - Sida 36 av 323

Bostadssektorns koldioxidutsläpp

Energy is an important issue in the current world which significantly affects sustainability and development. Energy generation and use are major sources of CO2 emissions which is one of the most important driving factors in global climate changes. The amount of energy used in house hold section can lead to estimation of the amount of CO2 emitted within this section which subsequently would be a ground to better management and maintaining a sustainable society. This study which is a bachelor?s project in sustainable energy, deals with estimation of CO2 emission from different types of residential houses in Sweden. An extensive literature review on energy use in Sweden by different residential sectors has been conducted.

Francisella tularensis subspecies holarctica : the curious case of a water- and mosquito associated bacterium in Sweden

Francisella tularensis, the causative agent of the zoonotic disease tularaemia, is highly contagious and potentially fatal for a wide range of wildlife species of the northern hemisphere, also humans. Although recognized as a pathogen for over 100 years, much still remains to be elucidated concerning the ecology and transmission of the bacterium, hence this literature overview aims at compiling data regarding the aquatic association and the role of mosquitoes in transmission of Francisella tularensis subspecies holartica, the sole subspecies in Sweden. While a linkage between the bacterium and natural waters stands beyond dispute, there is no consensus in the literature concerning its potential as a reservoir. However, two prevailing theories can be distinguished; one proposes the water association being mammaldependent and thus merely the result of contamination from semi-aquatic mammals living in close vicinity to the water source. The other, quite contrary, suggests mammal-independence and hence that water, possibly in association with protozoa, serves as an environmental reservoir for the bacterium.

Gestaltningsförslag till ny förskola på Zakrisdal

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.

Transporttidsmodellering vid provpumpning i heterogen jord : spårämnesförsök i en isälvsavlagring

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.

Klimatsimulering av ett kontorsrum : Hur de termiska stigkrafterna påverkar ventilationseffektiviteten

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.

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.

Den litterära nätsajten Vulkan.se och en ny modell för den litterära processen

The aim of this thesis is to investigate how the literary site Vulkan.se affects the conditions for publishing, distribution, incorporation in value systems and feedback in the literary process, as it appears in Lars Furuland?s model of this process. The purpose is also to propose an updated version of the model. This is achieved through a qualitative testing of Furuland?s theory.

Processbarhetsteorin i undervisning : ???Analys av två program som används av andraspråksinlärare

I have with this thesis sought to understand how chick lit could be useful in the classroom in the teaching of Swedish B-course in high school. Based on the model of critical literacy I am arguing that this genre would help to meet the objectives of the policy documents which, among other things, are to critically examine and analyze various types of texts.I have found that some of these texts could be used for analyzing and critically examine the ideological dimensions of texts and cultural heritage by the model of critical literacy, and also as a counterweight to the more traditional teaching of the canonical literature as a literary historical stuff that students should learn. I have also wanted to create a basis for discussions about literature in the classroom based on the chick lit genre. To do this I have, based on three themes and questions from the model of critical literacy, tried to focus on issues that might emerge from the ideological analysis and critical review. The model aims to deconstruct norms of society, and in the work of chick lit, I wanted to show how you could deconstruct norms around gender..

Estimering av kapitalkostnad för onoterade företag

The cost of capital for traded companies is basically assessed on information from thefinancial market. Small and non-traded companies are lack of this necessary financialmarket information in order to determine an appropriate equity risk premium and tocompute the cost of capital.In the absence of financial information necessary for an external investor, it is difficult toevaluate a non-traded company with the Capital Asset Pricing model (CAPM), which isbased on the financial market information. It measures only the systematic risk, which isthe contribution of one share to the market risk of a portfolio. It is therefore important tofind models that reflect the small and non-traded companies? real business value and theirunique characteristics.

Utveckling av kyl- och smörjsystem för ekobilen Agilis HCCI motor

Every year, KTH participates in the Shell Eco Marathon, a competition whose goal is to design a vehicle that can go as far as possible using only the equivalent energy of one liter of petrol fuel. This year, one of KTH?s contributions to this race is the Agilis prototype; a car powered by a uniquely configured HCCI-engine developed at the university. The engine is dependent of several subsystems in order to work properly, among other, systems for cooling and lubrication.Combustion engines are in need of a cooling system that reduces the heat developed during the combustion. In general, two main types of cooling systems are employed; either air cooling, where the outside of the cylinder is exposed to a flow of the surrounding air, ore water cooling, where water flows in tubes around the engine, and the heat are transferred by the water to the surrounding air through a heat exchanger.The purpose of the lubrication system is to prevent the friction that builds up in the interference between moving parts in the engine.

FEM?modeller för expansionsanalys av piplines

REINERTSEN AS performs expansion and buckling analyses of pipelines using ANSYS, afinite element modelling and analysis tool. In an expansion analysis the pipeline is modelledwith thin?walled pipe elements called PIPE20 which allows plastic deformation. However, ina recent analysis the results retrieved from the PIPE20 element were incorrect for strainsabout 1 percent. One main issue was that the PIPE20 element overestimated the strains.The purpose with this Master Thesis was to become familiar with the theories and analysismethods used in pipeline design.

BIM i planeringsarbetet : Effective planning by using BIM

AbstractThe importance of good construction planning affects the final costs of the production and the timing of the project. Planning for building projects has been studied with the aim of identifying how three week planning appears in the construction industry today.A case study has been conducted in Navisworks Simulate to assess whether the software is suitable to connect the task schedule with the BIM model to create a 4D model. 4D models are used for performing 4D construction simulation to visualize the project. In order to use the benefits of the model, investment in equipment and software is required. This means higher costs for the companies.

Analys av artificiella marktyper vid vatten med hjälp av GIS, Värmlands län 2007

On commission of the County administrative board in Värmland County a method was developed for analysis of the occurrence of artificial land use at lakes and watercourses. With artificial land use is meant land significantly affected by man. Two bases have been used to carry out the analysis. In one of the analysis the vegetation database and in the other GSD¹-Marktäckedata (land cover data) was used (this method has been used by County administrative board in Jönköping County).The analysis comprises all watercourses within Alsterälven river basin. The digital water bodies are created by the Swedish Meteorological and Hydrological Institute on the basis of GSD-Översiktskartan (general map).

Energieffektivisering genom förvärmning av flis till kokare med sekundärvärme

The Swedish pulp and paper industry meets higher demand for energy efficiencyi mprovements with increasing energy prices and changes in the Swedish renewable energy certificate system. One action of energy efficiency improvement is by using secondary heat, that otherwise would have been treated as waste heat, for use in a system with lower temperature demands. The aim of this Master´s thesis is to identify possible secondary heat sources in a typical Swedish pulp and paper mill and to investigate what economic benefits the secondary heat will provide when being used for pre heating of wood chips to a kraft digester.The Master´s thesis focuses on three secondary heat sources; dry warm air, warm water and moisture saturated warm air located inside the pulp or paper mill. Two types of kraft digesters are simulated within this study, a typical Scandinavian digester and a modern twin vessel steam phase digester.Due to quality aspects and low temperature level drying is the drying technology with dry warm air rejected. Using warm water in direct contact with wood chips increases the quantity of water to the evaporation plant and thus reduced pulp or paper production and is therefore also rejected.

Hållbar Ö ? en analys av möjligheterna att försörja ett modellösamhälle i Stilla Havet med solel

The goal of this paper is to provide a model for a sustainable electricity system to an island, in the Pacific Ocean near the equator.The method which has been used is to model supply and demand of electricity in the computer program Stella, through the creation of a dynamic system that balances them against each other. The result from the model will then be used to calculate the electricity price per kWh for the island.The result of the work is that electricity from solar energy is comparable with electricity produced from oil, if the oil pays for all its external costs, and the potential for pumped hydro storage plants is located. It also requires that consumers of electricity can be their own producers to avoid the expenditure of tax and reducing the cost of distribution. But since oil is a finite resource and has had a rising cost in recent years, while solar energy has had a declining cost, perhaps this will be a more competitive solution in the future.

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