Sökning: "Tracer"

Visar resultat 1 - 5 av 285 avhandlingar innehållade ordet Tracer.

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

    Författare :Johan Arvelius; [2005]
    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; NATURAL SCIENCES Physics Geocosmophysics and plasma physics Space physics; NATURVETENSKAP Fysik Geokosmofysik och plasmafysik 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

  2. 2. Effect of Hyporheic Exchange on Conservative and Reactive Solute Transport in Streams Model Assessments Based on Tracer Tests

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Karin Jonsson; Uppsala universitet.; [2003]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; conservative; hyporheic exchange; model; reactive; retention; solute; sorption kinetics; stream transport; temporal moments; tracer experiment; Geovetenskap; NATURAL SCIENCES Earth sciences; NATURVETENSKAP Geovetenskap; Sedimentology; sedimentologi;

    Sammanfattning : Understanding of the processes affecting solute transport in flowing water is important for the possibility to predict the evolution with time of polluted stream systems. This thesis presents tracer experiment methodology and model developments for solute transport in streams, with special focus on retention processes and their effect on solute stream transport. LÄS MER

  3. 3. Hydrological Transport in Shallow Catchments: tracer discharge, travel time and water age

    Detta är en avhandling från KTH Royal Institute of Technology

    Författare :Sofie Safeyeh Soltani; Vladimir Cvetkovic; Bijan Dargahi; Jan Olof Selroos; Andrea Rinaldo; [2017]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hydrological transport; travel time; water age; tracer discharge; Lagrangian pathway approach; pathway lengths; numerical modeling; Mark- och vattenteknik; Land and Water Resources Engineering;

    Sammanfattning : This focuses on hydrological transport in shallow catchments with topography-driven flow paths. The thesis gives new insight to kinematic pathway models for estimation of tracer discharge at the catchment outlet. LÄS MER

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

    Detta är en avhandling från Stockholm : KTH

    Författare :Kjartan Gudmundsson; [2003]
    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; TECHNOLOGY Civil engineering and architecture Building engineering; TEKNIKVETENSKAP Samhällsbyggnadsteknik och arkitektur 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

  5. 5. Some Aspects on Macroscopic Mixing in a Tundish

    Detta är en avhandling från KTH Royal Institute of Technology

    Författare :Chao Chen; Anders Tilliander; Lage Jonsson; Pär Jönsson; Guoguang Cheng; Seppo Louhenkilpi; [2015]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; continuous reactor; tundish; tracer; macroscopic mixing; water model; CFD; turbulence models; inclusions removal; inclusions deposition; dynamic removal; Materials Science and Engineering; Teknisk materialvetenskap;

    Sammanfattning : Two aspects on macroscopic mixing in a continuous flow system – metallurgical tundish were studied. Specifically, 1) the first focus was on salt solution tracer mixing, which is important for tundish design from perspectives of tracer technology and Residence Time Distributions (RTD) as well as for the understanding of the macroscopic mixing in tundishes. LÄS MER