Sökning: "Tracers"

Visar resultat 1 - 5 av 173 avhandlingar innehållade ordet Tracers.

  1. 1. Calibration and quality assessment of DESCARTES : grabsampler for stratospheric tracers

    Författare :Johan Arvelius; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Adsorption; Balloon; Carboxen; CFC; Chloro-Fluoro Carbon; Grab sampling; Halocarbon; Molecular sieve; Stratospheric tracer; Tracer; Adsorption; Ballong; Carboxen; CFC; Halogeniserade kolväten; Klor-Flourkarbon; Spårgas; Stratosfärisk spårgas; Space physics; Rymdfysik;

    Sammanfattning : DESCARTES is a light-weight, balloon-borne grab sampler for stratospheric long-lived tracers developed at the University of Cambridge. 33 flights have been performed with two versions of the instrument at northern latitudes by the DESCARTES team at the Swedish Institute of Space Physics (IRF) in Kiruna during the years 1997-2000. LÄS MER

  3. 2. Analysis of tracer molecules from organic aerosols - Application of liquid phase microextraction to aerosol analysis

    Författare :Murtaza Hyder; Centrum för analys och syntes; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Liquid membrane extraction; Secondary organic aerosols; Enrichment; Tracers; Hollow fiber liquid phase microextraction; Biomass burning; Organic carbon;

    Sammanfattning : Airborne particulate matter is well known because of its adverse impacts on human health and its role in climate processes. In order to understand completely the role of aerosols in atmosphere, their chemical composition is of basic importance. LÄS MER

  4. 3. Imaging of Enzymes in the Steroid Biosynthetic Pathway : Synthesis of 18F-Labelled Tracers

    Författare :Maria Erlandsson; Bengt Långström; Franklin Aigbirhio; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; Organisk kemi; Organisk kemi; Organic Chemistry;

    Sammanfattning : This thesis deals with the synthesis and development of 18F-labelled alkyl etomidate and vorozole analogues, and their use as positron emission tomography (PET) tracers for the imaging of the steroid enzymes 11β-hydroxylase and aromatase. Two synthetic 18F-labelling approaches to the etomidate and vorozole analogues were developed, and the analogues were evaluated in some biological assays. LÄS MER

  5. 4. Physiological integration and morphological plasticity in extensive clonal plants

    Författare :Tina D'Hertefeldt; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Plant ecology; Maianthemum; Carex; Clonal plants; tracers; Växtekologi;

    Sammanfattning : Clonal plants show a large variation in physiological integration, i.e. the translocation of resources among ramets within the clone. LÄS MER

  7. 5. Iodine Isotopes (129I and 127I) in the Baltic Sea   : Tracer applications & environmental impact

    Författare :Peng Yi; Ala Aldahan; Glen Snyder; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; radioactive 129I; stable 127I; AMS; iodine species; nuclear reprocessing facilities; tracers; Baltic Sea; circulation; water exchange; environmental impact;

    Sammanfattning : 129I is a radioactive isotope (T1/2= 15.7 million years) produced through natural and anthropogenic pathways, but the anthropogenic production is presently dominating the Earth’s surface environments. LÄS MER