Search for dissertations about: "isotopic ratios"

Showing result 1 - 5 of 33 swedish dissertations containing the words isotopic ratios.

  2. 1. Quantitative applications of secondary ion mass spectrometry : solid-state diffusion and mass fractionation studies

    Author : Ulf Södervall; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Secondary ion mass spactromy SIMS ; isotopic ratios; elemental semiconductors; ionazion mechanisms; mass fractionation; high pressure; diffusion; activation parameters; isotope effects;

    Abstract : .... READ MORE

  4. 2. Numerical simulations of the isotopic composition of stratospheric water vapour and methane

    Author : Martin Ridal; Cornelius Schiller; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; meteorologi; Meteorology;

    Abstract : The middle atmosphere is an important area of the Earth's atmosphere, but our understanding of the dynamical and chemical processes in that region is still limited. Water vapour and methane both fulfil the requirements for tracers due to their long lifetimes and have frequently been used to study dynamical processes. READ MORE

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

    Author : Kjartan Gudmundsson; KTH; []
    Keywords : 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;

    Abstract : 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. READ MORE

  6. 4. Studies of artificial mass bias in isotopic measurements by inductively coupled plasma mass spectrometry

    Author : Henrik Andrén; Luleå tekniska universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Chemistry of Interfaces; Gränsytors kemi;

    Abstract : Mass spectrometry, and especially inductively coupled plasma mass spectrometry (ICP-MS), suffers heavily from mass bias, or instrumental mass discrimination. The nett result of this effect is the preferential transmission, most often of heavier ions through the mass spectrometer. READ MORE

  7. 5. Isotopic analyses of biological materials by single and multi-collector sector field ICP-MS

    Author : Anna Stenberg; Luleå tekniska universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Applied Geology; Tillämpad geologi;

    Abstract : Investigations concerning naturally occurring, mass dependent isotope fractionation of transition elements in biological materials have only been carried out during a very short period of time. Due to the lack of detailed descriptions of the analytical performance in previously reported work, the major focus of this study has therefore been to evaluate aspects of sample preparation and detection for obtaining precise and accurate isotopic ratios by multi-collector inductively coupled plasma mass spectrometry (MC- ICP-MS) using high mass-resolution. READ MORE