Santamarina, J. Carlos

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Now showing 1 - 6 of 6
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    Physical Properties of Geomaterials Datasets
    (Georgia Institute of Technology, 2015-05) Santamarina, J. Carlos ; Roshankhah, Shahrzad
    Abstract for Chapter 3 dataset: Energy-related geosystems often impose extreme temperatures and loading conditions on the surrounding medium, so granular materials must be selected or engineered to satisfy heat transfer requirements and mechanical stability. In this work, the thermo-mechanical response of some natural and engineered granular materials was investigated by subjecting dense specimens to vertical load under zero lateral strain boundary conditions with concurrent thermal conductivity measurements. The materials studied were quartzitic sand with and without metal coatings, fly ash, diatomaceous earth, ceramic microspheres and hollow glass microspheres. Dry and densely packed hollow glass microspheres, ceramic microspheres and naturally occurring diatomaceous earth were found to be more compressible than sands, but exhibited very low thermal conductivity and very low stress-dependent gain in thermal conductivity. At the other extreme, dense sands combined the high thermal conductivity of quartz with the benefits of metal coatings to render the highest thermal conductivity values among the tested materials; while mechanically stable, dense sands were found to experience pronounced changes in thermal conductivity with stress. Analytical predictions show that saturation with high thermal conductivity liquids will enhance the effective thermal conductivity of granular materials more than the changes attained with metal coatings. Interparticle heat conduction processes and contact resistance explain the measured conductivity values obtained with the granular materials tested in this study.
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    Bio-Inspired Porous Network Topology for Optimal Injection and Withdrawal Processes in Soils
    (Georgia Institute of Technology, 2014-02) Arson, Chloé ; Santamarina, J. Carlos
    Bronchi, arteries and veins, tree branches and roots, exhibit a fractal topology, i.e. networks formed by channels that successively split in to smaller channels. A thorough literature review shows that self-similar topologies justify most empirical power laws encountered in nature and engineering design. Fractal models match but do not explain observations. Is the fractal topology optimal for all transport processes taking place between a porous system and a host medium? According to the constructal theory, the topology of a flow system should optimize an energy potential. The underlying assumption is that any network should have a purpose, a configuration and constraints. The main theoretical assumptions and developments of the constructal theory are presented. The thermal efficiency of an isolated heat exchanger pile is analyzed for different topologies. Simulations show that slender network components are preferable to isotropic topologies only if the contrast between soil and pile thermal conductivities is between 1 and 2 orders of magnitude. The orientation of fragmentation of the heat exchanger should also depend on potential variations of thermal properties across soil layers. The applicability and limitations of the constructal theory to optimize injection and withdrawal processes in soils is discussed.
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    Methane recovery from hydrate-bearing sediments
    (Georgia Institute of Technology, 2011-04-30) Santamarina, J. Carlos ; Tsouris, Costas
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    Flow test evaluation
    (Georgia Institute of Technology, 2008-02-29) Santamarina, J. Carlos
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    Pressure core testing chamber 1) multi-sensor 2) maintained fluid pressure
    (Georgia Institute of Technology, 2008-01-01) Santamarina, J. Carlos
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    Joint studies between Intevep and Georgia Tech
    (Georgia Institute of Technology, 2000) Santamarina, J. Carlos