Theses and Dissertations from UMD

Permanent URI for this communityhttp://hdl.handle.net/1903/2

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

Browse

Filters

2004 - 200912010 - 20111

Settings

Subject: search.filters.subject.porosity

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Quantification of Permeability-Porosity Relationships in Seafloor Vent Deposits: Dependence on Pore Evolution Processes
    (2011) Gribbin, Jill Leann; Zhu, Wen-lu; Geology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Hydrothermal mineral deposits formed along seafloor spreading centers help regulate the transfer of heat and mass from Earth's interior to the oceans. Aqueous fluids circulate within the seafloor and are emitted through vent deposits, formed from interaction between vent fluids and seawater. These deposits evolve as they react physically and chemically with venting fluids and seawater, therefore changing transport properties, such as permeability and porosity. In this study, measurements of permeability and porosity were used in conjunction with microstructural observations to identify evolution of permeability-porosity relationships (EPPRs) for vent deposits. EPPRs are power-law relationships relating permeability and porosity through an exponent, alpha, which is sensitive to changes in these properties. These relationships are important for understanding pore evolution processes and fluid distribution, in addition to their effects on environmental conditions within vent deposits.
  • Thumbnail Image
    Item
    Characterization of Pore Structure and Crack Propagation in Concrete Using X-Ray Computed Tomography
    (2004-12-13) Hunter, Opio Konata; Amde, Amde M; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This thesis utilized the method of computed tomography to quantify the pore structure and the development of cracks in concrete specimens due to delayed ettringite formation. The pore structure is responsible for the passage of harmful substances through the concrete matrix, while delayed ettringite formation causes expansion and internal cracking in concrete structures; particularly in prestressed and precast concrete elements. Computed tomography is a relatively new technique that can be utilized to determine the pore structure and crack propagation in concrete specimens within the mm to micrometer range. The experiment was successful in quantifying the pore structure in the specimens. The pore sizes and total porosity of each specimen were determined along with the pore size distribution on diameter and volume. A comparison was then made with the mercury intrusion porosimetry technique. However, the second objective of analyzing internal cracking due to delayed ettringite formation was not met.