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289 Uppsatser om Rotor diameter - Sida 3 av 20

Utvärdering av en subjektiv metod för att skatta mängden trädbiomassa längs vägkanter :

Forest biomass is becoming an increasingly important source of renewable energy, and thereby the demand is increasing. There is currently 213 000 km of forest roads in Sweden that could be suitable for biomass harvesting. Harvest of biomass along forest roads both provides biomass and maintains the quality of the roads. Currently, the volume of biomass along roads can only be assessed post harvest, chipping and industry deliverance. As the decision of whether or not to harvest should preferably be based on more than experience, the TJ-method has been proposed. The TJ-method is a subjective method to quickly determine the dry matter quantity with the assessment being conducted from the roadside.

Betydelse av lövinslag, död ved och variation i träddiameter för artrikedomen hos småfåglar

Forest management contributes to the changes in forest structure by turning heterogenous forests of varied age into homogenous forests of similar age and thus affect bird species depending on different structures or habitats which are lost during forestry. In this report, a study was made to investigate how the amount of decidious trees, dead wood and variation in tree diameter affect bird diversity. The purpose of this study was to be able to give forest management guidelines to increase bird diversity. This study was conducted by investigating 65 transects in forests of different structure south of Linköping, Sweden. Along the 65 transects, birds were inventoried as well as the vegetation.

Vad är ?rätt? gjutkvalitet? Hur uppnås det?

Ever since ABB has begun diecasting their rotors instead of permanent mold casting it,variation in the quality of the cast has arisen. Diecasting is performed in three differentmachines, M1, M2, M3 with 400, 660 respectively 800 tons of die locking pressures.The aim of this thesis is to answer the following questions:What is the ?right? cast quality? How is the right quality achieved?For sizes 160-180 solutions will be proposed that consider eccentricity between thelaminate and the short circuit ring as well as elimination of the thin Al film that appearson the outer periphery of the rotors.Through considering the statistic material the most often diverging rotor type has beenidentified and one of the actual rotors has been sent to a laboratory to be analyzed inorder to establish the current defects. The result of the analysis shows that there areplenty of gas- and oxide-porosity.It has been proved that every time the dies temperature decreased below 120°C thecontent of gas porosity increased. It is due to rapid solidification of metal that flowsthrough the ?cold? laminate.It has confirmed that enhanced porosity in squirrel cage causes high impedance in therotors.

Vindkraftsetablering i skog

This thesis assignment at C-level is focused on calculation models and prediction methodswhish can be used in the stage we call ?prospecting? of possible windmill locations. Thelocation is southeast of Halmstad at the Farm ?Stjernarpsgods?. The rapport has two mainareas directed towards this task.

Volymsrapportering vid terrängtransport av virke

This report is a B.Sc. Forestry thesis work at the school for Forest Management, SLU. The work was an assignment from the forest owners? association Mellanskog. The aim of the work where to investigate the economical result of removing undergrowth trees before first thinning, and a follow-up of the contractors and their compliance with Mellanskog standards. This thesis work was divided in three parts: The first was to find a relation between the net volume from the first thinning and the cost of cleaning undergrowth trees. Secondly there was a follow-up in the field, to investigate whether the contractors have done the undergrowth cleaning according to Mellanskog?s directives.

Konstruktion av säkerhetslagerför svänghjul

This thesis is the result of the investigation and solution of a mechanicalproblem regarding flywheel malfunctions. A flywheel is, in short, a devicethat relies on a rotating object?s moment of inertia to store energy overshort time spans. This project is part of the development of a fourthflywheel prototype at the division for electricity at Uppsala university,which uses magnetic levitation to keep a hollow cylinder rotating at veryhigh speeds inside a vacuum chamber. Should the magnets fail however, orsome other error occur that leads to an uncontrolled state of rotation, thecylinder needs to be stabilized mechanically by a device usually referredto as ?back-up bearing?.

Produktivitet vid stubbskörd :

Stump harvest could be found in the late 1970?s and the early 1980?s. And now when the prices on energy are high it has become an interesting topic again. This work has been conducted within Holmen Skog?s stump harvest testing in Norrköping.

Förröjning i förstagalling - vad kostar det och följer utförarna instruktionerna?

This report is a B.Sc. Forestry thesis work at the school for Forest Management, SLU. The work was an assignment from the forest owners? association Mellanskog. The aim of the work where to investigate the economical result of removing undergrowth trees before first thinning, and a follow-up of the contractors and their compliance with Mellanskog standards. This thesis work was divided in three parts: The first was to find a relation between the net volume from the first thinning and the cost of cleaning undergrowth trees. Secondly there was a follow-up in the field, to investigate whether the contractors have done the undergrowth cleaning according to Mellanskog?s directives.

Produktion av finfibrig ull genom avel och utfodring - inkorsning av merino i sveafårsbesättningar :

To produce fine fibre wool as a complement to lamb meat production, Merino and Svea sheep are currently being crossbred in the county of Jämtland. The aim of this study was to evaluate growth and wool quality of the first crossbred lambs. In addition, a literature study about nutritional effects on wool production has been carried out. The literature study showed that fine fibre wool should foremost be achieved through directed breeding. Nutritional requirements of the sheep at different stages of production should determine their feeding.

Analys av lageregenskaper utifrån mätningar i testrigg

Vertical hydropower units has a rotating mass of up to 1000 tons. For the generator and turbine to work well the rotating system is required to be centered in relation to the surrounding structure. This is achieved by means of radial bearings. The dynamic characteristics of these bearings have a strong impact on the overall rotational dynamics of the total system and thus influence the vibrations in the unit. At Vattenfall Research & Development in Älvkarleby ongoing research is taking place on how the bearing parameters should be represented in the rotor dynamic calculations.

Risken för spridning av röta vid förröjning i granskog i södra Sverige :

Root rot causes large economical losses for Swedish forestry. The spread of root rot can partly be prevented by treating the spruce stumps in thinnings. Late pre-commercial thinning (PCT) is one of the forestry measures where stump treatment is not used. Late PCT can be defined as: The act of cleaning the stand with the aim of improving accessibility and sight within the stand, and so to increase the mean stem´s volume during the first conventional thinning. The aim of this study was to examine how late PCT is performed, its spatial extent and if it aids the spreading of root rot. The study was limited to encompass late PCT before first conventional thinnings in spruce stands in southern Sweden. Samples of spruce stumps were taken from four stands where late PTC had been carried out.

Mätning av sorteringsdiameter för talltimmer vid Kastets sågverk

För att få en rättvis betalning av timmer för både säljare och köpare gäller det att det sågtimmer som kommer till sågverken mäts in på rätt sätt. För att sågverken ska kunna hålla nere råvarukostnaden gäller det att minska råvaruspillet och öka optimeringen av stocken. Ett led i att hålla nere kostnaden är att få en snabb och effektiv mätning vilket har lett till en ökad automatiseringsgrad på sågverken. Setra Kastets sågverk byggde 2010 en ny timmersortering. Under sommaren 2011 började Kastet uppleva problem med den automatiska underbarksmätningen som sker med hjälp av trakeidmetoden.

Mätning av stamdiameter med markstående scanner :

Booth for operational planning of harvesting and for long term planning, data is today collected manually. Intensive objective field inventories are usually too expensive. To enhance optimisation of timber flow from forest to industry Moore efficient methods for measuring tree stems of standing trees are needed. The performance of terrestrial laser scanners have improved and these could possibly be used within forestry in the future. The objective of this study was to validate how a terrestrial laser scanner could be used to measure stem diameter, and to test how the errors depend on distance from the scanner and tree species. Two plots (one pine and one spruce) were used for this study.

Planteringsförbandets inverkan på bildningen av kärnved hos tall (Pinus sylvestris L.) : en modellsimulering av planteringsförbandets inverkan?

The current state of knowledge indicates that there is more than one factor that initiates heartwood transition. This study supports its hypothesis on the theory that heartwood is formed by a fixed fraction of the annual growthring, 0,5 to 0,8 rings. To calculate heartwood volume modelings were carried out in four different pine stands with different spacings, 0,75, 1,25, 1,5 and three meters. The model indicates heartwood diameter (HWD) and is based on four explanatory variables, height (H), crown ratio (CR%), diameter breast height (DBH) and tree height (TH). The shifting plant spacing results in varying growth rate in the juvenile stage.

Förekomst av penicillinkänslighet hos blododlingsisolat av Staphylococcus aureus

Staphylococcus aureus is the most clinically important Staphylococcus species and is associated with high mortality in patients with positive blood cultures. S. aureus bacteria may cause a variety of disease manifestations ranging from minor skin infections to life-threatening conditions such as pneumonia, meningitis, osteomyelitis, endocarditis, toxic shock syndrome (TSS) and sepsis. This microorganism belonging to the gram positive cocci may also be part of the normal flora. In Sweden, penicillinase-stable penicillins are the primary alternatives to treat S.

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