Ph.D. candidates

Yoni Israeli

Yoni Israeli

Ph.D student, supervised by Simon Emmanuel
Room 129 North

Impact of mineral dissolution and precipitation on the wetting behavior of non-aqueous phase liquids in groundwater systems.

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During the past few years the focus of my research has been to develop state-of-the-art microscopy and numerical techniques to study the interaction between minerals and fluids at a macro and nanometer scale. My main study is aimed at exploring a fundamental scientific problem of exploring how mineral alterations influence wetting behavior. My research is aimed to determine the way mineral precipitation, dissolution and replacement impact the wetting behavior of non-aqueous phase liquids (NAPLs) in rocks and soils at the micrometer and nanometer scales. We expect that alteration of wettability at the pore scale will affect field scale phenomena, such as pollutant mobility. Since wetting behavior controls the adhesion of liquid contaminants to minerals, my study is expected to have important practical implications to the quality of groundwater and to the environment.
I am also studying the way in which minerals undergo weathering from the macro to the nanoscale. I developed a numerical model to assess the effect of grain size and rock composition on chemical weathering and grain detachment. The model simulates the weathering of a rock comprising grains with various sizes composed of two different minerals with different reactivities. Our simulations showed that grain detachment represents more than a third of the overall weathering rate. We also found that as grain size increases, the weathering rate initially decreases; however, beyond a critical size, the rate became approximately constant. Our results could help predict the sometimes-complex relationship between rock type and weathering rate (for more details: https://www.earth-surf-dynam.net/6/319/2018/esurf-6-319-2018.html).

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Pritom Sarma

Ph.D candidate
Advisor: Prof. Einat Aharonov
310 South
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Interests: Rock Mechanics, Flow in Porous Media, Earthquake Physics and Computational Mechanics.
Research: I am currently working on injection induced seismicity, firstly I am looking at the micromechanical evolution of pore-pressure and slip phases in fault gouge using a granular mechanics based discrete element model (DEM) coupled with flow in porous media. We are looking at how the slip phases in the fault gouge changes with increase and decrease in far field injection pressure.
       
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Secondly, I am trying to address the problem on why around the world, many induced earthquakes are seen around large distances of an injection site over a short period of time, which can’t be accounted by any crustal scale hydraulic diffusivity. We theorize that permeability evolution with increasing injection and pore pressure acts as a competing mechanism to aid in the occurrence of “faster than diffusion ruptures” which causes these far field earthquakes in short time since injection.
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