Sökning: "Natural abundance of stable isotopes"

Visar resultat 6 - 10 av 21 avhandlingar innehållade orden Natural abundance of stable isotopes.

  1. 6. Abundance and fractionation of rare earth elements in calcite and other secondary minerals in fractures in the upper kilometre of crystalline bedrock, SE Sweden

    Författare :Olga M. Maskenskaya; Mats Åström; Kjell Billström; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; secondary minerals; rare earth elements; isotopes; crystalline bedrock;

    Sammanfattning : This thesis focuses on the geochemistry of secondary minerals, mainly calcite but also others such as fluorite and Ca/Al silicates, precipitated throughout the last 1.5 billion years in fractures of crystalline rock, SE Sweden. LÄS MER

  2. 7. Alternative methods for analysing moisture transport in buildings : Utilisation of tracer gas and natural stable isotopes

    Författare :Kjartan Gudmundsson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tracer gas; water vapour permeability; diffusion; surface diffusion; isotopic analysis; deuterium; oxygen-18; fractionation; vapour barrier; transient numerical modelling of diffusion; Building engineering; Byggnadsteknik;

    Sammanfattning : New methods, based on tracer gas measurements and isotopicanalysis can be used to evaluate the moisture properties ofbuilding materials and provide the means for forensic analysisof the origins and history of excessive water in buildings, theimmediate practical consequences of which will be the abilityto improve the moisture performance of constructions. It is shown, in theory and through measurements how thewater vapour permeability of porous building materials can witha good degree of accuracy be estimated with tracer gasmeasurements that provide an efficient alternative to the cupmethod. LÄS MER

  3. 8. Fractionation of the stable silicon isotopes studied using MC-ICP-MS : analytical method developments and applications in geochemistry

    Författare :Emma Engström; Ben Reynolds; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied Geology; Tillämpad geologi;

    Sammanfattning : In spite of the high Si abundance in natural systems, expected significant mass-dependent fractionations, and the importance of the element in many areas of the Earth sciences (focusing on e.g. LÄS MER

  4. 9. Paleoclimate and seasonality on Sumatra during the Late Glacial and Holocene : Insights from biomarkers and climate model simulations

    Författare :Lars Petter Hällberg; Malin Kylander; Frederik Schenk; Rienk Smittenberg; David Naafs; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Holocene; Late Glacial; biomarkers; organic geochemistry; climate model; hydrogen isotopes; stable isotopes; paleoclimate; alkanes; GDGT; brGDGT; H-GDGT; bacterial community shifts; paleothermometry; precipitation reconstruction; peat; geokemi; Geochemistry;

    Sammanfattning : Deep atmospheric convection in the Indo-Pacific Warm Pool (IPWP) is a key driver of the Hadley and Walker Circulations that modulate the Asian-Australian monsoons and the El Niño Southern Oscillation (ENSO). Temperature and rainfall seasonality, i.e. LÄS MER

  5. 10. Effects of morphometric isolation and vegetation on the macroinvertebrate community in shallow Baltic Sea land-uplift bays

    Författare :Joakim Hansen; Lena Kautsky; Erik Bonsdorff; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; lagoons; macrofauna; macrophytes; hydrophytes; charophytes; ecological succession; structural complexity; habitat complexity; habitat selection; species composition; biodiversity; stable isotopes; food web; Terrestrial; freshwater and marine ecology; Terrestrisk; limnisk och marin ekologi; Plant Ecology; växtekologi;

    Sammanfattning : Shallow sheltered Baltic Sea bays are ecologically important habitats that harbour a unique vegetation community and constitute vital reproduction areas for many coastal fish species. Knowledge about the invertebrate community in these bays is, however, limited. LÄS MER