Rapporten behandlar aeroba dränkta biobäddar som biologiskt reningssteg i avloppsreningsverk. Syftet med examensarbetet är att studera de dränkta biobäddarna i Järbo och Kungsgården avseende reduktion av näringsämnen och parametrar som pH, syre och belastning. Rapporten har dels en teoridel där funktionen hos dränkta biobäddar genomgås samt en praktisk del där avloppsreningsverken i Järbo och Kungsgården studerats avseende reduktion av bland annat fosfor, kväve, COD, BOD. Studien omfattades av två provtagningsomgångar om vardera en vecka. Studien har utförts under våren 2004..

Different methods for shelterwood cutting have been used in differ-ent parts of Europe since the middle ages. The use of shelter wood cutting in Norway spruce (Picea abies (L.) Karst.) forests in Sweden met a revival in the early 1990s as an alternative for the dominating clear-cutting system when silvicultural costs increased dramatically for the latter. Shelterwood cutting systems involve some possible problems but also a lot of positive effects. Among the problems are increased risk of wind throw and damage of the remaining shelter trees caused by the cutting operation. Positive effects are for example a valuable growth in the remaining trees and increased biological di-versity. This study is based on a total of 79 trees from 4 different treatments in a spruce shelterwood, cut in 1994, in the middle of Sweden (62,4º N).

This thesis has been conducted at Saab Bofors Dynamics AB. The purpose was to investigate if a non-linear missile model could be stabilized when the optimal control signal is computed considering constraints on the control input. This is particularly interesting because the missile is controlled with rudders that have physical bounds. This strategy is called Model Predictive Control. Simulations are conducted to compare this strategy with others; firstly simulations with step responses and secondly simulations when the missile is supposed to hit a moving target.

The environmental debate is more intensive than ever before and the demands on companies increase. There are a number of methods to make it easier for the companies to fulfil the demands. Life Cycle Assessment (LCA) end ecodesign are some of the methods that can be used. Syntronic AB has the possibility to reduce the products´ environmental impact in the design phase. Therefore it is important for the company to make it possible to visualize the negative environmental impacts a product can cause in an easy way. It is also important to visualize for there clients if any improvement is possible. The purpose of this thesis is to develop a simplified model.

This thesis intends to analyse conditions for a successful implementation of consociational democracy, as a democratic model in Afghanistan. The lack of critical reviews regarding the democratisation-process in Afghanistan initiated the purpose of this study.Lijpharts democracy model was used as the basis in the comparative study. Along with empirical evidence regarding how the complex process of democracy in Afghanistan is progressing, the study investigated whether the identified conditions occurred or not.The choice of which democracy model to use can be crucial for the democratic possibilities to even survive and become established in conflict-affected communities. The principle of consociational democracy is that it is an empirically based normative model that aims to organise the state in a way that works against the risks of majority domination and oppression against the minority.The empirical case study revealed that a majority of the conditions were not met, which then can counteract the possibilities for consociational democracy in Afghanistan. The study has critically examined the prospects for the success of consociational democracy in Afghanistan, and it can be assessed that there is a limited probability for a successful applying of this model..

From 1710 to 1713 the plague raged through the Swedish province of Scania. Other studies have been made on how the disease affected the society during the epidemic. This study tries to focus on the recovery afterwards. How did the population and the farmsteads recover after the plague? Statistics from parish registers and cameral records show interesting patterns in the demography, and that the recovery was far from complete 1720.

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.

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.

This thesis work is the last part of the Master of Science education inmechanical engineering at KTH, Stockholm.The aim of this project was the development of a Multi-zone modelfor NOxformation in Diesel engines. Because of the stringent emissionlegislations, great effort is made to decrease the fuel consumption and theharmful emissions of internal combustion engines. Computer simulationsplay a decisive role in this context because they substitute the expensiveand time-consuming laboratory tests.The model is based on a multi-zone approach and uses the wellknownExtended Zeldovich Mechanism which gives a relation to calculatethe NO formation rate using the concentration of different gas speciesinvolved in the process.All the most important phenomena involved in the Diesel combustionhave been modelled. A special attention is then paid to the equilibriumconcentration calculation; this is a significant part of the model whichstrongly influences the following steps.A Simulink model has also been developed. This second version isbased on the previous model and it is made especially to allow theconnection with other external softwares, GT-power in this case.

Listed corporations achieve effectiveness through segmentation of investors. Categorization of like- minded investors diminishes goal incongruence. This thesis aim to examine an Investor models accuracy, provided by a Professor Emeritus in Economic Psychology in 2001. This model segments investors as active, passive, speculative and naive investors. This thesis has a demarcation to private investors on the Swedish stock market. It has a deductive and qualitative approach as the purpose is to study the Investor model.

Simulation means running a model of a system with suitable input and observing the corresponding output. Real-time environment simulation is a special kind of simulation used to simulate a control system's environment in real-time. This is done to test the control system before it is used in its real environment. In this project, computer simulation of a certain kind of environments, called track-based systems, is studied and a general model for track-based systems is developed. In this model, track layouts are represented by graphs, which is a flexible and extensible representation and a method for visualizing these layouts is presented.

Sweden have 419 000 km road in the country and about half of these roads is forestroads. The forest road net most important mission is to make it possible to deliver wood from the forest to the industries. With a raw material that is spread over a large area the road network is important. Each year has the forest road network been extended with about 1 700 km new roads. To decide if a new road is to be built different forest road cost estimation models has been used.

Deicing fluids based on Propylene glycol are used at Stockholm Arlanda airport to remove or prevent ice on aircrafts. The high oxygen demand of propylene glycol can cause oxygen depletion in rivers downstream from the airport if not collected. Mass balance calculations made by Swedavia indicate that the actual amount of gathered propylene glycol is underestimated. Suspicions that propylene glycol is degraded in the stormwatersystem designed to collect deicingfluids, called the B-glycolsystem, have to be investigated in order to establish with certainty that no propylene glycol in other ways leaves the B-glycol system.The purpose of this study was to determine if degradation of propylene glycol is present in the B-glycol system and also to estimate the extent of the degradation. Propylene glycols high biological oxygen demand can cause oxygen depletion in waters downstream from Stockholm Arlanda airport if not collected.

"Speak up! I can?t hear you"This qualitative study is built on an investigation of a newly instated model that is used when building or renovating schools. The principles of the model are based on building schools with an open plan design where the walls are made of glass and the classrooms are not shut closed by walls, instead the classrooms are completely open except from screens that are used to indicate the ambit of the rooms. This model has been well debated and that is the reason why we chose to do this study.The purpose of this study is to find out how students and teachers experience this model. To do this we have done interviews and observations.

Calcareous fens constitute a specific habitat which is uncommon in Europe and protected by the EU habitat directive due to its importance to several threatened species. Hagebyhöga in Östergötland is a calcareous fen habitat included in the Natura 2000 Networking Programme. Adjacent to the existing fen, a degraded fen area is situated. The area has been used for agriculture for several years but is now going to be restored to its former state by the county administrative board of Östergötland.When working with restoration of degraded fen areas it is important to aquire knowledge about the chemical soil conditions. Plant growth limited by phosphorus and low fertility are characteristic conditions for calcareous fens, whilst arable land usually is highly fertile and limited by nitrogen.The purpose of this study is to bring forth useful knowledge for restoring the degraded calcareous fen of Hagebyhöga.