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9 Uppsatser om Baggy webs - Sida 1 av 1

Simulering av valkar i pappersrullar : och analys av de slappa stråk som uppkommer

A baggy paper web has parts that are longer than neighboring parts. One of the assumed reasons for bagginess is thickness variations of the paper. In the roll the thicker streaks then add up to form a ridge. In the ridges the paper is strained and during storage the strain may become permanent. When the paper unreeled it is then baggy.

Hur biodiversitet på ekosystemnivå skiljer sig mellan olika habitat

Biodiversity can be described as the total variation of life forms, where diversity ranges from gene level up to the ecosystem level. The diversity can be calculated in a number of ways, and this study use one of these methods. In this study empirical food webs have been used and analyzed, where eleven characters are defined and used as parameters to calculate the Euclidean distances between food webs that describe the variation that may exist within classes of terrestrial, marine and freshwater habitats. The class who stood out and showed the greatest diversity at the ecosystem level was the marine food webs, which showed a high value of the average euclidean distance. The other networks were not as distinctive and the average of the euclidean distance in these classes was comparatively low..

Förändring av pappersegenskaper vid lagring under dragspänning

SammanfattningI en pappersrulle är de yttre lagren utsatta för dragspänning. Om det finns variationer i rullens diameter i form av valkar finns det risk för att papperet förlängs irreversibelt i dessa positioner och orsaka slappa stråk. Den deformation som uppstår vid långvarig belastning av papper kallas krypning.Uppgiften i detta arbete var, att på lab., simulera valkar genom att utsätta pappersremsor för konstant dragspänning av olika storlekar. En av frågeställningarna var om egenskapsförändringar kan påvisas när papper utsätts för konstant inspänningskraft under en längre tid. De parametrar som undersökts var töjning, kryphastighet och relaxation, även mätningar på papperets mekaniska egenskaper dragstyrka, brottöjning och dragstyvhet har utförts i detta arbete.De papperskvalitéer som undersöktes var 71g/m2 MG-papper, 80g/m2 optisk liner och 135g/m2 liner.

Klassifikationens roll på www: en studie av webbmiljöns påverkan på klassifikationens principer och funktioner

Principles that guide how a classification system should be structured have existed for more than a century. Traditional classification principles can be of great value for the design of classification schemes directories on the web. However, there are differences between the library context in which these principles originated, and the web. This thesis aims at investigating how changes in the context of classification affect the application of traditional principles of classification on the web. Another purpose is to see what implications this has for the design of classification schemes on the web.

Genomgång av kemikalieförteckning som exempel på uppströmsarbete : en identifiering av utfasningsämnen i spillvattnet

Benthic invertebrates play important roles as feeding resources for many organisms in different food webs. Shifts in predation of these organisms can generate cascading effects and potentially lead to the disappearance of one or more species from a site. Cascading effects can bring impacts to organisms who aren?t even directly involved, why studies in this field are important for understanding sudden changes in ecosystems. I examined the predation from fish and waterfowl on benthic invertebrates in the shallow and eutrophic Lake Tåkern in the plains of Östergötland County, southern Sweden.

Teoretisk och experimentell utvärdering av Lättelement AB:s takinfästning

Lattelement AB in Ornskoldsvik is one of the leading companies in Sweden in composite elements in walls, floors and roofs in particular. The company supplies elements to buildings located with a wide geographical variation, which means that the products are subjected to very different climate with regard to snow, wind and humidity. This places high demands and requires the elements to withstand large variable loads.The elements are made of lightweight beams with flanges of structural timber and beam webs made of OSB. These are bound together by nogging pieces with the same kind of structure. On top of the beams a nailed and glued plywood is added to absorb compressive forces and on the underside of the element a sheet of steel is added for tensile absorption.These elements are then attached to the building framework in different ways depending on the particular element height, loads and the structual supporting material of the frame work.

Klimatinducerade fenologiförändringar och dess effekter i näringsväven

The climate affects animal populations through several processes. These processes includereproduction, phenology and the success of hunting. By influencing the phenology of species theclimate also affects the way species interact. If a climate-induced phenology change promotes abasal species to bud earlier in the spring for example, this will affect the links to other species inthe food web due to a time lag in the tropic levels above. This dependence, that a predator has tobeing synchronous to its prey, is called the match/mismatch hypothesis (MMH).

Predation på evertebrater under tidig vår i sjön Tåkern

Benthic invertebrates play important roles as feeding resources for many organisms in different food webs. Shifts in predation of these organisms can generate cascading effects and potentially lead to the disappearance of one or more species from a site. Cascading effects can bring impacts to organisms who aren?t even directly involved, why studies in this field are important for understanding sudden changes in ecosystems. I examined the predation from fish and waterfowl on benthic invertebrates in the shallow and eutrophic Lake Tåkern in the plains of Östergötland County, southern Sweden.

Löslighet och metylering av kvicksilver i en förorenad sjö (Ala-Lombolo) i Kiruna kommun :

Transformation of inorganic mercury (Hg) to methyl mercury (MeHg) is a biotic process that is proposed to be conducted primarily by sulphate reducing bacteria (SRB). The formation of MeHg is of great interest because it is the mercury species that biomagnifies to the greatest extent in the aquatic food webs; about 90 % of all Hg in fish is MeHg. Our understanding of factors involved in the production of MeHg is very important for making a reliable risk assessment. The purposes of this study were to investigate the different factors that control the solubility of Hg and the production of MeHg in a contaminated lake sediment. The lake Ala-Lombolo, Kiruna municipality, is well-known to be contaminated by mercury from different sources. Sediment cores were sampled at three different locations (N, SW and SE) in the lake and divided in three different layers; 0-5, 5-10 and 10-15 cm.