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1966 Uppsatser om Clear Air Turbulence - Sida 1 av 132

Projektering av vindkraft i turbulensintensiva områden : med fallstudie för Wallenstams planerade park vid Skuggetorp

Along with the rapid expansion of wind power in Sweden during the last decades the competition about favorable areas has hardened. This among other reasons has caused the projectors to look into development of wind power in forests. There are several aspects regarding fatigue loads on the constructions that are severe in complex terrain, among which turbulence is one. The levels of turbulence which are accepted in order for the turbines to face a life length exceeding 20 years are regulated by the International Electrotechnical Commission, (IEC). In order to keep the turbulence below these levels there are three major steering tools to use: The ambient turbulence decreases with height and can therefore be regulated by the hub height of the turbines.

Klarluftsturbulens (CAT) : går det att undvika?

Turbulens är ett väderfenomen som har orsakat många olyckor och incidenter. Speciellt farligt är klarluftsturbulens eftersom fenomenet ej är synligt för blotta ögat, samt att det kan uppstå mycket plötsligt. Mycket pengar och resurser har lagts ned för att ta fram system som skall kunna detektera och automatiskt rapportera turbulens. Denna uppsats beskriver kortfattat hur några av dessa system fungerar samt hur systemen skall bidra till att piloter lättare skall kunna förbereda för eller undvika turbulens. Uppsatsen beskriver system för prognostisering, detektering och automatisk rapportering av turbulens med tyngdpunkt på klarluftsturbulens..

Utvärdering av svensk vindkraft : Skillnaden mellan skogs- och traditionella placeringar

During the last years commercial Wind Power Turbines (WPT) has become larger regardingto the generator sizes and hub heights. Available hub heights around 100 meters is nowcommon, which has led to profitability for WPT located in forests where there normally are tolow wind speeds. The current knowledgement regarding turbulence and the variation in thewind profile for the outcome of the power production for the WPT in forests is limited.In this Master of Science thesis an investigation concerning forest located wind power plantshas been made. The purpose has been to investigate if plants located in forest perform lesscompared to wind power turbines located at more common locations.The analyses are based on statically material for determining the availability,production/generator size, production/hub height, production/swept area and how thetopography affect the production results.The analyses show that the variation in production result for WPT located in forest comparedto turbines located at other locations is small. The availability is high and the productionresults are good..

Design and Analysis of an All-optical Free-space Communication Link

Free Space Optics (FSO) has received a great deal of attention lately both in the military and civilian information society due to its potentially high capacity, rapid deployment, portability and high security from deception and jamming. The main issue is that severe weather can have a detrimental impact on the performance, which may result in an inadequate availability. This report contains a feasibility study for an all-optical free-space link intended for short-range communication (200-500 m). Laboratory tests have been performed to evaluate the link design. Field tests were made to investigate availability and error performance under the influence of different weather conditions.

Effekter av kalavverkning på mindre boreala sjöars vattenkvalitet

Forestry is an important industry in Sweden, with clear-cut as the most commonly used method for harvesting. Here the long-term impact of clear-cut on lake water quality (dissolved organic carbon (DOC), nitrogen, phosphorus and pH) has been investigated, based on 23 lakes sampled during autumn. Data for additional 15 lakes sampled for the Swedish monitoring program were also used. Lakes were classified as 5, 25, 40 and 60 year based on data of the forest age in the catchment, gathered from the Swedish national forest inventory. Clear-cut lakes were classified as 5 years (>20% of the catchment clear-cut during the last 10 years).

Simulering av kabelbränder i sekundära säkerhetssystem med CFD-koden SMAFS

This report contains CFD-simulations of cable tray fires in nuclear power plant applications with the CFD-code SMAFS. Furthermore the report evaluates the use of CFD-codes within this kind of problems. The assessment of this report is that there is a tendency towards the good use of CFD-codes but before using it solely more research has to be done on the subject..

De nya riksdagspartierna och den politiska dagordningen

Engblom, Gustav (2009) De nya riksdagspartierna och den politiska dagordningen ?The new parilament parties and the political agenda.?1988 and 1991 the swedish parties Miljöpartiet, Ny demokrati and Kristdemokratiska samlingspartiet made it over the 4 percent threshold and successfully entered the Swedish parliament. Sweden was once described as one of the most stable political systems in the world, but the parliament elections of 1988 and 1991 showed that Sweden was no exception from the growing instability in west democratic political systems.The stability and instability that followed in the west democratic political systems is believed to be explained by the political parties? efforts to adjust to changes in their political environment. This has lead them to cartelize and the cartel party is believed to prefer stability over triumph for various reasons.The established political parties are believed to be able to manipulate the political agenda in such a way that political topics that would have caused great turbulence in the political system, if debated, are kept away from the political agenda.

Clear-cut and substrate characteristics important for the occurrence of the beetle Upis ceramboides

Disturbances, such as fire and wind, are important for saproxylic beetles (= beetles depending on decaying wood) to gain substrate in boreal forests. Clear-cutting is an example of a man-made disturbance. Measures such as prescribed burning have been made to resemble natural disturbances. The aim of this study was to see which clear-cut characteristics are important for the occurrence of the saproxylic beetle Upis ceramboides. This is a species favored by open habitats and is said to respond positively to forest fires. The distribution area in Sweden for this species has decreased during the last two centuries and I wanted to see if there were differences between clear-cuts in Hälsingland, where it is very rare and decreasing, and Norrbotten where this study was conducted.

Mapping of clear-cuts in Swedish forest using satellite images acquired by the radar sensor ALOS PALSAR

This study presents results for observing forest changes in Sweden using multi-temporal L-band satellite data and is a part of the JAXA?s ALOS Kyoto and Carbon Initiative. An extensive dataset of images acquired by the Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) is investigated for clear-cut detection in boreal forests in northern Sweden (Lat. 64°14? N, Long.

Kampen mellan etablissemang och näthatare - En studie om näthatsdebatten

This essay examines the Swedish debate on Internet hate with focus on theories concerning Internet as a public sphere, sociocultural turbulence and subaltern counterpublics. Examining material fromnewspapers, alternative news media and discussion forums, with an hermeneutical influenced method, the task is to understand the Internet hate debate, and the study wishes to discover its relations to biggercontexts, such as social transformations and power dynamics. The conflict evolves between the establishment (journalists, writers, politicians et cetera) on one part, and Internet ?haters? on the other.The examined theme also shows a conflict where the two combatants show not only two opposite views on what Internet hate is, but also shows two different conceptions of the world..

FUNDAMENTALA SAMBAND I TURBULENTA PERIODER: - Om tillväxtens och avkastningens påverkan på börsvärdet under perioden 1997-2005

This thesis investigates the effect of profit growth and profitability on market capitalization amongst Nordic companies during the turbulent period 1997-2005. Our results suggest that profitability have a significant impact on market capitalization for six of the nine years studied, whereas profit growth does not seem to affect market capitalization. Consequently, our results imply that the effect of other factors on share price performance may be greater than previously suggested. These findings are only partly in line with theories on corporate valuation which suggest that market capitalizations are to a great extent driven by both profit growth and capital returns, regardless of whether the stock market is particularly unstable..

Preferensaktier och obligationer som fastighetsfinansiering

The recent turbulence in the financial markets has contributed to the banks becoming more restrictive to lend to real estate financing. Deleveraging in Europe's banking sector has also contributed to banks reducing their leverage and increasing capital adequacy to meet the new requirements. Loan-to-value ratios in real estate loans have fallen while banks' interest margins have increased, which has made property investors to look for alternative sources of funding in the capital markets. The two most interesting forms of financing for real estate right now is bonds and preferred shares as they fit property companies that generate stable and predictable cash flows. A bond is an interest-bearing debenture certifying that the purchaser has lent money to the company that issued the bond.

Sova med fienden - Orsaksförklaringar till uppkomsten av oheliga allianser i svenska kommuner

Over the last years there has been a considerable change in Swedish municipals. The number of municipals run by a rainbow coalition, a coalition made up of parties from different political blocks, has increased dramatically. Despite this clear pattern little research has tried to explain this increase. My thesis? aim is to try and clear the water around this subject by answering three questions about this type of coalitions.

Hur påverkas bentiska funktionella födogrupper av kalavverkning? : Effekt på abundans, samt återhämning, av funktionella födogrupper efter kalavverkning kring små vattendrag.

Forestry affects most of the forest-covered land in Sweden. In the landscape, the most common stream type is headwaters, which are important sites for many processes and organisms in both the terrestrial and the aquatic ecosystems. The aim of this study was to investigate how the abundance of benthic invertebrate functional feeding groups in headwater streams develops after clear-cutting and if it also is possible to detect a change in the composition of feeding groups. The study also attempts to determine what factors have an effect on temporal changes in abundance of these groups. For the study, 11 sites in northern Sweden were sampled for benthic invertebrates using a Surber-sampler, and for each site canopy-cover and pH was obtained.

Går det att mäta blodtryck med fotopletysmografi och bioakustisk sensor i kombination?

The aim of the work was to investigate the possibility to combine information from PPG and bio-acoustic technology to extract information that is related to the blood pressure. The measurements have been carried out with several different configurations. First the relation between arterial sounds and the PPG-signal was studied. After those measurements with both PPG and the bio- acoustic technique was concluded on people in different positions and after riding a bike. The goal was to vary the blood pressure.

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