• Login
    View Item 
    •   DSpace@RPI Home
    • Rensselaer Libraries
    • RPI Theses Online (Complete)
    • View Item
    •   DSpace@RPI Home
    • Rensselaer Libraries
    • RPI Theses Online (Complete)
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Diffusion in complex systems

    Author
    Homolova, Veronika
    View/Open
    174856_Homolova_rpi_0185E_10527.pdf (3.083Mb)
    Other Contributors
    Watson, E. Bruce; Lewis, Daniel J.; Rogers, Karyn; Spear, Frank S.;
    Date Issued
    2014-12
    Subject
    Geology
    Degree
    PhD;
    Terms of Use
    This electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.;
    Metadata
    Show full item record
    URI
    https://hdl.handle.net/20.500.13015/1325
    Abstract
    Diffusion is an important process in the crust and mantle of the Earth and has a large bearing on geochemical processes. The results of three experimental studies that examine complex diffusion behavior related to Earth systems are reported. First, lithium diffusion and the associated diffusive isotopic fractionation in olivine is examined. Lithium is found to diffuse by two mechanisms, interstitial and vacancy, and partition between the two sites. The magnitude of diffusive isotopic fractionation is found to be large and is best described by a beta factor of 0.36 - 0.42. Second, diffusive fractionation of lithium isotopes in a synthetic harzburgite rock is investigated. Large isotopic fractionation is found. The experiments are best represented by a model that considers both the grain boundaries and grains and shows that the grain boundaries are the most likely place of isotopic fractionation. Third, the effective diffusivity of manganese is examined in a polycrystalline rock consisting of quartz and minor enstatite. The effective diffusivity of manganese is found to decrease as the proportion of enstatite increases in the polycrystalline rock. The experimental results are modeled using numerous approaches used in the past for diffusion in heterogeneous media. A numerical model that closely matches the physical aspects of the experimental matrices is also explored. The results show that the presence of a phase, in which the diffusant is compatible, in the polycrystalline rock will decrease the effective diffusivity of an element through the rock. This must be accounted for when considering long range diffusion through most of the rocks in the crust and mantle.;
    Description
    December 2014; School of Science
    Department
    Dept. of Earth and Environmental Sciences;
    Publisher
    Rensselaer Polytechnic Institute, Troy, NY
    Relationships
    Rensselaer Theses and Dissertations Online Collection;
    Access
    Restricted to current Rensselaer faculty, staff and students. Access inquiries may be directed to the Rensselaer Libraries.;
    Collections
    • RPI Theses Online (Complete)

    Browse

    All of DSpace@RPICommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    Login

    DSpace software copyright © 2002-2022  DuraSpace
    Contact Us | Send Feedback
    DSpace Express is a service operated by 
    Atmire NV