The Subsurface Environmental Processes Group (SEP Group) led by Dr. Joaquín Jiménez-Martínez at the Swiss Federal Institute of Aquatic Science and Technology (Eawag) and ETH Zurich, in collaboration with the Center for X-ray Analytics and the Concrete and Asphalt Laboratory at the Swiss Federal Laboratories for Material Science and Technology (Empa), is seeking a motivated postdoctoral researcher with expertise in X-ray imaging techniques, image analysis, and porous media research to investigate transport in unsaturated porous media. The postdoctoral position is funded for one year, with the possibility of an extension, and is expected to start asap.
Project Background
The transport of solutes has been traditionally considered chaotic in turbulent flows, such as those found in rivers. However, discoveries in the last decade indicate that solute transport in porous media, such as soils, can also be chaotic despite commonly present laminar flow conditions because of their inherent spatial heterogeneity and anisotropy. In particular, chaos potentially enhances solute dispersion, resulting in increased solute mixing efficiency.
Previous studies of chaotic transport in porous media have revealed the dominant role of their inherent topological complexity in accelerating a solute’s plume deformation and in enhancing mixing. However, the observation and quantification of chaos has not yet been achieved experimentally for porous media that resemble natural systems and under the presence of more than one phase in the pore space, i.e., for unsaturated porous media. These conditions are typically found in natural and industrial porous media. Understanding the impact of chaos on solute transport in such systems will thus contribute to better assess contaminant transport in groundwater systems (to plan for its remediation) and to optimize efficiency in several industrial processing fields.
Job Description
Your postdoctoral position will focus on two main aspects: (I) exploring for the first time the use of X-ray micro-tomography (X-ray μCT) for the quantification of chaotic advection and chaotic mixing in porous media resembling natural systems, and (II) assessing consequently the control exerted on these processes by the liquid phase saturation degree, i.e., the fraction of the pore volume occupied by the liquid phase. You will combine the experimental investigation with a hydrodynamic and topological characterization of the experimentally tested system using numerical modeling. You will have the opportunity to carry out the X-ray μCT experiments and corresponding image analysis using the state-of-the-art infrastructure at the Center for X-ray Analytics at Empa. The highly interdisciplinary nature of this project will allow you to have direct contact with researchers and experts in different disciplines at three leading research institutes, fostering new research avenues. The combination of advanced imaging experiments with image analysis and numerical modeling will also offer the possibility of performing advanced research where experimental and computational methodologies are strongly used synergistically.
Your profile
- You should have a PhD in physics or engineering or geosciences or related fields, with a solid background/experience and interest in computational methods.
- You should count with a strong background in imaging techniques (especially experience with X-ray-based imaging is a great plus) and image analysis, as well as a clear interest in applying these techniques for studying relevant environmental and industrial processes. Experience in the study of flow and transport in porous media is of advantage.
- You will have the opportunity to work directly with experts in many different disciplines. A great disposition to work in team and also independently, and the ability to come up with innovative solutions is essential.
- We expect a strong disposition to work and to foster positive interactions within a very international and diverse group.
- You should count with good communication skills to effectively share project findings with the scientific community.
We look forward to receiving your application including a letter of motivation, CV (including publications list), a brief (1 page) statement of research interests, and contact details of at least 2 referees.
Contact: Joaquin Jimenez-Martinez jjimenez@ethz.ch / joaquin.jimenez@eawag.ch
Web page: https://www.sepgroup.ethz.ch/