Sökning: "TWI"

Visar resultat 1 - 5 av 8 avhandlingar innehållade ordet TWI.

1. 1. A GIS-based landscape analysis of dissolved organic carbon in boreal headwater streams

   Författare :Jan-Olov Andersson; Lars Nyberg; Hjalmar Laudon; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; boreal forests; wetlands; vegetation types; headwater streams; catchment hydrology; streamwater chemistry; DOC; GIS; terrain analysis; DEM; slope; wetness index; TWI; Freshwater ecology; Limnisk ekologi; Biology; Biologi;

   Sammanfattning : In boreal catchments, stream water chemistry is influenced and controlled by several landscape factors. The influence of spatially distributed variables is in turn dependent on the hydrological scale. LÄS MER

3. 2. Plants go with the flow : predicting spatial distribution of plant species in the boreal forest

   Författare :Ursula Zinko; Christer Nilsson; Håkan Rydin; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; boreal forest; vascular plant; species richness; wetness index; soil pH; bryophyte; lichen; substrate; stand age; plot size; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

   Sammanfattning : The main objectives of this thesis are to study if a topographic wetness index (TWI) could be used as a tool for predicting the spatial distribution of vascular plant species richness in the boreal forest as well as to study congruence in species richness between vascular plants, liverworts, mosses and lichens. A wetness index ln(a/tanβ) based on topography was used to assign a specific TWI-value to every 20 x 20m grid in two 25 km2 boreal forest landscapes (differing in average soil pH) in northern Sweden. LÄS MER

4. 3. Experimental and theoretical investigation of the laser cutting process

   Författare :Jetro Pocorni; Ali Khan; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Manufacturing Systems Engineering; Produktionsutveckling; Maskinteknik;

   Sammanfattning : This thesis concerns experimental investigations of laser cutting with theoretical and practical discussions of the results. The thesis is made up of three papers which are linked in such a way that each of them studies a different aspect of laser cutting: In paper I the two major laser types in cutting, namely CO2 and fiber lasers, are compared to each other by a self-defined cut efficiency. LÄS MER

5. 4. Hydrological Modelling, Topographical Influence and Yield Mapping in Precision Agriculture

   Författare :Andreas Persson; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Spatially distributed hydrological modelling; Precision Agriculture; Yield mapping; Topographical wetness index; Drainage area; Lantbrukshydrologi; marklära; agricultural hydrology; Soil Science;

   Sammanfattning : The use of topographical data in hydrological and agricultural applications has increased with GPS data availability and the concept of precision agriculture. This thesis investigates the relationships between topography and in one case simulated soil moisture and in the other case yield. LÄS MER

7. 5. Friction stir welding of copper canisters for nuclear waste

   Författare :Therese Källgren; Rolf Sandström; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; Friction Stir Welding FSW ; Copper; Welding; Finite Element Method FEM ; Materialvetenskap; Materials science; Teknisk materialvetenskap;

   Sammanfattning : The Swedish model for final disposal of nuclear fuel waste is based on copper canisters as a corrosion barrier with an inner pressure holding insert of cast iron. One of the methods to seal the copper canister is to use the Friction Stir Welding (FSW), a method invented by The Welding Institute (TWI). LÄS MER