Search for dissertations about: "carbon isotopes"

Showing result 11 - 15 of 84 swedish dissertations containing the words carbon isotopes.

  1. 11. Isotopes as Mechanism Spies : Nucleophilic Bimolecular Substitution and Monoamine Oxidase B Catalysed Amine Oxidation Probed with Heavy Atom Kinetic Isotope Effects

    Author : Susanna MacMillar; Olle Matsson; Anita Hussénius; Daniel M. Quinn; Uppsala universitet; []
    Keywords : Organic chemistry; nucleophilic bimolecular substitution SN2; kinetic isotope effects; precision conductometry; monoamine oxidase B MAO B; reaction mechanism; carbon 11C 14C kinetic isotope effect; ion pairing triple-ion formation; para-substituted benzyl chlorides; tetrabytylammonium cyanide; Organisk kemi;

    Abstract : This thesis concerns the study of reaction mechanisms by means of kinetic isotope effects (KIEs). Studies of the nucleophilic bimolecular substitution (SN2) reaction had the dual purpose of improving our fundamental understanding of molecular reactivity and assessing the ability of kinetic isotope effects to serve as mechanistic tools. READ MORE

  2. 12. Achieving carbon isotope mass balance in northern forest soils, soil respiration and fungi

    Author : Björn Boström; Alf Ekblad; Phil Ineson; Örebro universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; 13C; Carbon cycle; Ectomycorrhizal fungi; Forest soil; Microbial respiration; Soil respiration; Stable isotopes; Biology; Biologi; Biology; Biologi;

    Abstract : Northern forests contain a large part of the global terrestrial carbon pool and it is unclear whether they will be sinks or sources for atmospheric carbon if the climate warms as predicted. Stable isotope techniques provide unique tools to study the carbon cycle at different scales but the interpretation of the isotope data is impaired by our inability to close the carbon isotope mass balance of ecosystems. READ MORE

  3. 13. Isotope-based constraints on sources and processing of black carbon, carbon monoxide, and brown carbon in South Asia

    Author : Sanjeev Dasari; Örjan Gustafsson; August Andersson; Jos Lelieveld; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; South Asia; Air Pollution; Short-Lived Pollutants; Atmospheric Abundance; Model-Observation Mismatch; Radiocarbon; Stable Isotopes; Applied Environmental Science; tillämpad miljövetenskap;

    Abstract : The highly populated South Asian region is facing rapid economic growth and urbanization. Here, both climate- and health-affecting atmospheric agents such as light-absorbing aerosols black carbon (BC) and brown carbon (BrC), trace gas carbon monoxide (CO), are often found in relatively high levels compared to in other regions. READ MORE

  4. 14. An evaluation of the distributions of polychlorinated biphenyls and organic matter in coastal sediments

    Author : Anders Jönsson; Örjan Gustafsson; Detlef Schulz-Bull; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Polychlorinated biphenyls PCBs ; organic carbon; sediment; stable carbon isotopes; Earth sciences; Geovetenskap;

    Abstract : The objective of this thesis is to improve the understanding of what processes and mechanism affects the distribution of polychlorinated biphenyls (PCBs) and organic carbon in coastal sediments. Because of the strong association of hydrophobic organic contaminants (HOCs) such as PCBs with organic matter in the aquatic environment, these two entities are naturally linked. READ MORE

  5. 15. Our Bones, who art contaminated : Glues, strontium isotopes, and mobility in early Swedish Christians

    Author : Crista Adelle Wathen; Kerstin Lidén; Sven Isaksson; Christophe Snoeck; Stockholms universitet; []
    Keywords : HUMANIORA; HUMANITIES; Strontium isotopes; contamination; conservation; glues; Christianity; mobility; early Christians; Sweden; Varnhem; Västerhus; bones; teeth; Scientific Archaeology; arkeologi med inriktning mot laborativ arkeologi;

    Abstract : This thesis aims to build upon previous research into contamination and its effects on isotopes by focusing on the strontium isotopic ratio (87Sr/86Sr), which is used in mobility studies to study the movements of past humans and animals and to build past economic trading networks. Contamination is a broad topic, and in the scope of this thesis, it concerns the introduction of contaminants from the soil after interment and the post-excavation preservation efforts. READ MORE