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437 Uppsatser om Tree rings - Sida 12 av 30

Optimering av driftläggningar i Fortums nät

Future emission legislation puts great emphasis on increasing the efficiency of the engine, thereby reducing fuel consumption. The tribological contact between cylinder liner and piston ring is where an great amount of energy is lost due to friction, and by reducing these losses an reduction in fuel consumption can be achieved.The aim of this thesis was to evaluate the tested piston ring coatings against a plasma sprayed cylinder liner and rank these combinations of materials for friction and wear resistance. The coatings that were tested was Cr + Al2O3, (Al,Cr)N, two types of CrN and WC / C.The experimental tests were performed with a so-called pin-plate, where used oil with addition of an acidic mixture of sulfuric and nitric acid to mimic the acidic condensate formed when exhausts recirculate, were added with a continuous flow. The results were then analyzed by weighing, studies by optical microscopy and scanning electron microscopy (SEM) and profile measurements.The results from each material combination were that the plasma coated cylinder liner wears too aggressively in order to yield a ranking of the piston ring coatings based on the parameters of friction and wear resistance. It is therefore proposed that an alternative coating on the cylinder liner should be developed, lacking the large abrasive wear on piston rings and that can withstand the corrosive environment resulting in engines equipped with EGR.

Gallringsinventering från helikopter utrustad med profilerande laser och kamera för låghöjdsfotografering

Today Holmen Skog finds and selects suitable thinning stands using data on upper height and basal area. These figures are often based on basic forest data that has been updated with the help of growth prediction models. The problem is that these figures are not always correct. The aim of this study was to investigate if a combination of data from a profiling laser and a digital camera for low elevation photography, can be used for collecting data on number of stems per ha, tree species mixture as well as basal area weighted mean height and upper height for stands. The possibility to use these data to assess the need for thinning cutting was also investigated.Laser data and aerial photographs were collected from a helicopter operating at an approximate height of 100 meters.

Effektivare röjningssätt med kedjeröjsågen?

After the mandatory rules for clearing was removed in 1994, the clearing area has increased in Sweden. After the storms Gudrun and Per, the areas became planted with new plants, mainly spruce, but also other tree species. Storm areas are now being invaded by naturally rejuvenated birch in the tilling tracks. Since the birch often is initially growing faster than the spruce it is inhibiting the growth and is also damaging the spruce. The purpose of this thesis is to study the new brush saw with chain and compare it with the conventional clearing saw, mainly in terms of performance and ergonomics. The results show that the new brush saw with chain is very good in almost all clearing operations compared to the conventional clearing saw.

Skogsbruksplanen - ett hjälpmedel i vattenförvaltningsfrågor? : en intervjustudie

After the mandatory rules for clearing was removed in 1994, the clearing area has increased in Sweden. After the storms Gudrun and Per, the areas became planted with new plants, mainly spruce, but also other tree species. Storm areas are now being invaded by naturally rejuvenated birch in the tilling tracks. Since the birch often is initially growing faster than the spruce it is inhibiting the growth and is also damaging the spruce. The purpose of this thesis is to study the new brush saw with chain and compare it with the conventional clearing saw, mainly in terms of performance and ergonomics. The results show that the new brush saw with chain is very good in almost all clearing operations compared to the conventional clearing saw.

Talande ord : En jämförande studie av taggar och kontrollerade ämnesord för indexering av skönlitteratur

How do you summarize the content of a fictional work, let?s sayLord of the Rings, into a few "telling" words that may represent it? This master?s thesis is a comparative study of how library users? freely chosen tags/keywords deviate from controlled vocabulary made by professional indexers when representing fiction. The thesis answers four main questions:? Do the tags that the library users give fictional works correspond to the categories used in professional indexing in Sweden?? Do the tags follow the standards for vocabulary, semantics and syntax used when indexing professionally?? Do the tags add something to document representations?? Are there differences between the tags used for adult fiction and the tags used for children?s literature?With a starting point in indexing theories of Frederick W. Lancaster, Annelise Pejtersen, and the semiotic theory of the indexing process of Jens-Erik Mai, 383 tags from totally 70 fictional works are analyzed.

Studie av belagda kolvringarmot plasmasprutat cylinderfoder : Med avseende på friktion och nötningsmotstånd

Future emission legislation puts great emphasis on increasing the efficiency of the engine, thereby reducing fuel consumption. The tribological contact between cylinder liner and piston ring is where an great amount of energy is lost due to friction, and by reducing these losses an reduction in fuel consumption can be achieved.The aim of this thesis was to evaluate the tested piston ring coatings against a plasma sprayed cylinder liner and rank these combinations of materials for friction and wear resistance. The coatings that were tested was Cr + Al2O3, (Al,Cr)N, two types of CrN and WC / C.The experimental tests were performed with a so-called pin-plate, where used oil with addition of an acidic mixture of sulfuric and nitric acid to mimic the acidic condensate formed when exhausts recirculate, were added with a continuous flow. The results were then analyzed by weighing, studies by optical microscopy and scanning electron microscopy (SEM) and profile measurements.The results from each material combination were that the plasma coated cylinder liner wears too aggressively in order to yield a ranking of the piston ring coatings based on the parameters of friction and wear resistance. It is therefore proposed that an alternative coating on the cylinder liner should be developed, lacking the large abrasive wear on piston rings and that can withstand the corrosive environment resulting in engines equipped with EGR.

Jobbiga biljetter

This bachelor?s thesis report aims to investigate the problems that exist with the ticketing systems ofthe various regional public transportation authorities, specifically with regards to inexperiencedtravellers and cross-county travel.This is done in part through a comprehensive survey for all of Sweden where both the regional publictransportation authorities and passengers were asked about their opinions, as well as a throughin-depth survey focused on the counties of Stockholm and Uppsala. The results of these surveys arethen compiled and analyzed to identify the biggest common problems.The tree biggest problems prove to be a complicated implementation, lack of availability and lack ofinformation. In order to improve the ticketing system it is therefore proposed to implement asimplified ticketing system, as well as improved accessibility and information.         .

Hur bokskogslagen blev till ? konflikter och lösningar 1964-1974

During the early Middle Ages beech forests (Fagus sylvatica L.) spread out over large parts of southern Sweden. They had a crucial role in human survival for hundreds of years. For various reasons, the beech forest area has decreased since the 1600s. Spruce planted on former beech forest land was the primary reason for the decline during the second half of the 1900s, which made many worried about the future of the beech forests and led to a beech forest act in 1974. This study describes the background to the beech forest act based on parliamentary official documents.

Rhododendron ur undersläktet Vireya - något om dess karakteristika och användning i nordiska vinterträdgårdar :

Present essay aims to introduce the reader to central topics regarding Rhododendrons of subgenus Vireya. As a result of a donation, the Swedish University of Agricultural Sciences, received a collection of Vireya from a local amateur grower, Kurt Myllenberg. Since the subgenus Vireya is uncommon in Scandinavian horticulture, the study tries to establish conditions for successful growing. The subgenus Vireya differ from the other Rhododendron species through mainly three characteristics: the presence of two tails, attached to each end of the seed; the ovary-style junction is tapering and the pedicels arises directly from a dome-like base and form an umbel and not a raceme. The subgenus is distributed mostly in the islands of Indonesia and New Guinea, but also from Malaysia to Nepal and in Australia. Since Vireya species mainly grows as epiphytes in the tree canopies, they need high drainage and not too much water.

Bluetoothlänk mellan PC och CAN

In order to measure the quality of the logs, one can with help of Fast Fourier Transform technique get the signals resonance peaks. With help of these peaks you can see whether the quality of a tree is good or bad. This report contains the work of a where a program has been developed to be able to process a vibration created by an automatic hammer hitting on a log of wood. From the processed signal the program should be able to show both the raw wavesignal and the processed measured data from the resonance peaks. Beyond the raw wavesignal and resonance peaks the program should also be able to control the automatic hammer.

Korrosion i insamlingsfordon

In order to measure the quality of the logs, one can with help of Fast Fourier Transform technique get the signals resonance peaks. With help of these peaks you can see whether the quality of a tree is good or bad. This report contains the work of a where a program has been developed to be able to process a vibration created by an automatic hammer hitting on a log of wood. From the processed signal the program should be able to show both the raw wavesignal and the processed measured data from the resonance peaks. Beyond the raw wavesignal and resonance peaks the program should also be able to control the automatic hammer.

Hantering av specialservice för DHL

In order to measure the quality of the logs, one can with help of Fast Fourier Transform technique get the signals resonance peaks. With help of these peaks you can see whether the quality of a tree is good or bad. This report contains the work of a where a program has been developed to be able to process a vibration created by an automatic hammer hitting on a log of wood. From the processed signal the program should be able to show both the raw wavesignal and the processed measured data from the resonance peaks. Beyond the raw wavesignal and resonance peaks the program should also be able to control the automatic hammer.

Automatiserad fasadrenovering

In order to measure the quality of the logs, one can with help of Fast Fourier Transform technique get the signals resonance peaks. With help of these peaks you can see whether the quality of a tree is good or bad. This report contains the work of a where a program has been developed to be able to process a vibration created by an automatic hammer hitting on a log of wood. From the processed signal the program should be able to show both the raw wavesignal and the processed measured data from the resonance peaks. Beyond the raw wavesignal and resonance peaks the program should also be able to control the automatic hammer.

Temperaturzoner för lagring av värmeenergi i cirkulärt borrhålsfält

The thermal response of a borehole field is often described by non?dimensional response factors called gfunctions.The g?function was firstly generated as a numerical solution based on SBM (Superposition BoreholeModel). An analytical approach, the FLS (Finite Line Source), is also accepted for generating the g?function. In thiswork the potential to numerically produce g?functions is studied for circular borehole fields using the commercialsoftware COMSOL.

Janusansiktet : En jämförande studie om synen på svenska luftstridskrafters utveckling under 1950-talet

I den försvarsdebatt som förts under 2013 och 2014 har det förekommit tydliga skillnader mellan den politiska och den militära nivån avseende syn på hur Försvarsmakten och de svenska luftstridskrafterna ska utvecklas.Varför finns det då denna skillnad? Eftersom det är en nu pågående process är det svårt att finna svaren då slutresultatet saknas. Istället söker denna uppsats förklaringen genom att jämföra skillnader och likheter i synsätt på luftstridskrafternas utveckling mellan den mili-tära och den politiska ledningen mellan 1948 och 1958, vilket omfattar en hel försvarsbe-slutsperiod. Analysen genomförs genom ett verktyg baserat på John Wardens 5-rings modell, applicerat på de svenska luftstridskrafterna, i syfte att identifiera mätbara variabler som se-dan jämförs utifrån den militära respektive den politiska synen.Undersökningen påvisar såväl skillnader som likheter i synsättet där skillnaderna i huvud-sak omfattar de stödjande delarna som till exempel infrastruktur som inte direkt ger militär effekt i duellsituationen vid ett militärt angrepp.Förklaringen till skillnader och likheter finns sannolikt i den maktkamp som enligt teorin na-turligt uppstår i en byråkratisk organisation som samtidigt ska vägas av mot den inre och den yttre strategin i det här fallet svensk säkerhetspolitik..

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