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8922 Uppsatser om Stability analysis - Sida 2 av 595

Rayleigh-Bénard konvektion.

AbstractConsider a ?uid being heated from below. The heating leads to an upward convectiveforce that is counteracted by the viscous forces of the ?uid. If the convectiveforce is large enough in comparison to the viscous forces the ?uid will be put in anunstable state.

Självförsörjande elgenerering : Kan Orust bli självförsörjande på förnybar el?

Orust Kretsloppsakademi is a nonprofit organisation, with a goal of annually generate the same amount of electrical energy that is consumed. Orust is an island on the west coast of Sweden, north of Gothenburg. The population of 15 000 reaches 40 000 during summer, due to the large amount of vacationer. The total electricity demand is 174 GWh a year with a maximum power need of 32 MW. This report presents an analysis for the plausibility of their plan and from a power system stability perspective, the effects on the electrical grid.The conclusion is that the restraints for development of power generation from wind, solar and wave generation, are the power systems capability to transfer power, primarily in the transformers of the grid.

Frekvensreglering i det nordiska kraftsystemet

Svenska Kraftnät is (together with the other transmission system operators of the Nordic power system) responsible for keeping balance between the generated and demanded power in the Nordic power system. Spontaneous load variations and system disturbances, however, lead to power imbalance followed by frequency variations. The frequency deviations can be limited to an acceptable level by the spinning reserve, mainly by hydro power control. But there are also other system properties which have a great influence on the frequency and system stability. The frequency and voltage dependence of the loads have a direct influence on the power balance.

Lettland-EU medlemskap, etnicitet och identitetskonstruktion

This paper examines whether membership in the European Union has contributed to democratic stability and integration in an ethnic diverse society. By studying the Latvian multicultural society, before and after membership in the EU, the author is looking for evidence of enhanced ethnic stability in the country brought through European integration. The author will analyze what the consequences have been, by adopting European regional policy, for a country that yet has to create a unified national identity. By analyzing different areas of the Latvian society, the author has concluded that the EU has played a small but yet not insignificant role for the Latvian domestic integration process..

Islastens inverkan på brottsannolikheten för glidning och stjälpning av betongdammar

There are many old dams in Sweden and, since few dams are constructed today, the main task in risk assessment on the existing dams is often to reduce the risk of failure. RIDAS (Swedish Guidelines on Dam Safety) is used when designing new dams and assess the existing ones. The guidelines include stability requirements for different failure modes, e.g. overturning and sliding, which imply that the load effect from e.g. uplift and ice load need to be less than the resisting loads or moments.

Design av en ejektorspädare samt ett system för partikelmassmätning av dieselavgaser

This master thesis was a subtask of a project called EMIR-1. The goal with the thesis was tobuild a system for particulate mass measurements in one of the engine test cells at KTH. Theparticulate mass measurements are planned to be measured with a TEOM.The exhaust gases must first be diluted with air before the sample is sent to the TEOM.Therefore an ejector diluter for this matter also was designed and evaluated in the thesis.Emissions measurements have been done both with and without dilution to determine thedilution ratio. Tests have been done for different speeds and loads.Problems with stability of the dilution ratio have been an issue throughout the process andpressure pulsations in the exhaust pipe are believed to be the cause. More tests have to be done tomake sure that this is the problem.One idea is to make the inner diameter of the diluter nozzle smaller and see if it changes thedilution ratio stability.

I väntan på framtiden : en studie av mindre företags förberedelseinför framtiden

Introduction: The world is changing rapidly and the uncertainty that characterizes today´s society makes companies preparations for the future crucial. Purpose: To examine how CEO:s in small companies look at the future and what kind of preparations they make in order to meet it. Hereby, our ambition is to find out whether there is a difference between companies working in industries characterized by different degrees of stability. Mode of procedure: The purpose of this thesis has been fulfilled by interviews with four CEO:s from industries characterized by different degrees of stability. Result: The companies working in relatively unstable environments tended to be relatively more flexible and have an emergent strategy formation process, whereas companies working in relatively stable environments displayed relatively less flexibility and tended to have a planning strategy formation process..

Vem bär kostnaden för regeländringar inom finansiella marknader? : en kvantitativ studie ur aktieägarnas perspektiv

As a consequence of a turbulent financial market with recurring recessions, the Basel regime was developed, an institutional change with the purpose to create enhanced financial stability through increased capital requirements and increased scrutiny of internal procedures. The Basel regime is an often recurring element in social debates where various aspects are discussed, one of which is whether it maintains its purpose to secure financial stability or whether it is cost effective, and if not, who gets affected by these potential costs.The majority of previously conducted research within this area agrees with the opinion that changes in the regulatory framework within the financial markets, such as the Basel regime, has led to reduced risk of bankruptcy for the banks which has contributed to increased global financial stability. However, research illustrates that these types of changes in the regulatory framework impose a financial burden leading to contradictions in the division of these costs between costumers and shareholders. This dissertation has been conducted from a shareholders perspective, out of which the study ?s three hypothesis has been created from.The data in this study is built upon the stock price from the three largest available banks? shares (based on total assets), in the 26 countries which are represented in the Basel committee from (2007) to (2013).

Epoxidised linseed oil as hydrophobic substance for wood protection : technology of treatment and properties of modified wood

Public concern about the release of toxic compounds from wood-based products drives legislation towards enforcing industries to find and use more sustainable solutions for wood treatment. Plant oils are good alternatives to treat wood, minimizing or even neutralizing the impact on the environment. Wood modification with epoxidised linseed oil (ELO) and acetic acid as catalyst has proven a suitable method to impregnate and protect wood. However, the mixture presents a serious inconvenience because of the quick polymerization of the ingredients that limits its practical application. Therefore, this study was designed to evaluate an alternative method using a two-step process which bypassed the problem above.

Kunskapens konstellationer: om ämnesanalys och tvärvetenskaplighet

The aim of this study has been to discuss ideas of knowledge within classification theory and subject analysis in the light of theories of fundamental changes in the production of scientific knowledge. Guiding questions have been: How have the conditions of knowledge production changed? How has interdisciplinarity as part of this development evolved? What assumptions lie behind theories of classification and subject analysis? How do these stand in relation to the alleged changes in the production and understanding of science? Three works about the changing conditions for knowledge production and the growth of crossdisciplinarity have been presented and discussed. These works stress the loosening up of boundaries between traditional knowledge domains and open up for discussions about how to organize knowledge production in the light of these changes. In the study it is argued that their works also could open up for discussions about the way knowledge is organized for retrieval purposes.

Inverkan av torrsubstanshalt och temperatur på kompostens syrabildning :

Composting is a process in which organic matter is mineralized by microorganisms. In January 2005 landfilling of organic waste was prohibited in Sweden. With this prohibition composting has become an important alternative to handle the produced organic wastes. One problem with continuous small-scale composting is the production of organic acids that will inhibit a further composting process. The aim of these theses was to study what effects temperature and dry matter content had on the production of organics acids, and what effect the organic acids had on the mineralisation of the substrate as well as the stability during storage of the product.

Mänskliga rättigheter vid en naturkatastrof : En jämförelse mellan Haiti och Thailand

There are three main purposes for this thesis; the first is to distinguish the possible violations that can occur in time of natural disasters. The second is to analyze if there is a correlation between political systems and how the effected country handles the aftermath of a natural disaster. The third purpose is to determine the role of the global community and what responsibility lies with them. The issue is often that the aid becomes the main object for discussion and analysis, but the focus rarely shifts to the effected State. Therefore the focus in this essay is the political system and how they cope with the human rights violations that can occur in a time of natural disaster.

Lodgepole pine - stability after thinning

SCA has today almost 300 000 hectares of their forest land planted with lodgepole pine(Pinus contorta var. latifolia). Due to initial extensive planting in the 1970ies the area oflodgepole pine forests in the thinning age has grown rapidly from the end of the 1990ies.During the years 1996-2005 first commercial thinning of lodgepole pine at SCA took place.The goal of the hereby presented study was to investigate the growth and stability in thosefirstly-thinned lodgepole pine stands a few years after thinning. Furthermore, the objectivewas to investigate the relationship between stand stability and different stand parameters.Additionally, lodgepole pine stem quality was estimated.The study is mainly based on the data collected during an inventory project carried out atSCA in 2008. Altogether 91 lodgepole pine stands in northern Sweden were measured afterthe first thinning.

Hisskärna av skalväggar i höga byggnader : Ett alternativ till den platsgjutna kärnan

A common way to stabilize high rise buildings is to use an elevator core built of concrete. Today, we use to build these elevator cores of in-situ concrete. Precast concrete twin wall (double wall) is a semi-finished product that has become more common in recent years. This diploma work studies how the twin wall works out as structural elements in an elevator core. The work also shows some possible ways of designing twin walls and highlights some important parts of the design that will be vital to the stability of the building.    The result shows that it is important to think through where the element joints should be placed.

SAB-systemets utveckling 1985-1997

The aim of this Master's thesis is to compare the 6th and the 7th editions of the classification scheme of the Swedish classification system (SAB) to reveal which principles are used concerning the development of this system during the period 1985-1997. Guiding questions are: What kind of changes has been conducted? How do these changes relate to development of other general classification schemes and to theories concerning revision work? The results of the analysis show that possibilities to use synthesis have increased by an extension of use of geographic and chronological subdivisions. The classification scheme has also been easier to use by elimination of parallel subdivisions and regularization of the scheme. To maintain stability revision is performed on selected subclasses.

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