August 5, 2019
Congratulations to Greg Engel, professor in the Department of Chemistry, Mark Rivers, Executive Director of the Center for Advanced Radiation Sources (CARS), and research professors, Peter Eng and Yanbin Wang, for earning grants from the Department of Energy's Office of Basic Energy Sciences. Read more about their projects below.
Engel's project is entitled, "Mapping energy transfer through cyanobacterial photosynthetic light harvesting antennas with in vivo 2D electronic spectroscopy to monitor photoprotective mechanisms."
Public abstract provided by the Department of Energy:
Cyanobacteria in the ocean account for much of the photosynthetic activity on the planet, produce much of the oxygen we breathe, and feed our ocean. These photosynthetic bacteria have evolved complex and dynamic photoprotective mechanisms to regulate photosynthetic activity and prevent production of damaging reactive oxygen species under high light or other adverse conditions. These photoprotective mechanisms permit excellent low-light performance of the solar light-harvesting antennae without risk of damage to the sensitive charge-separation apparatus. This process is actively regulated by the organism and in vivo studies are necessary to observe how the processes work. Prior work in this area has used fluorescence changes to monitor photoprotection, but this approach can miss non-radiative relaxation processes or changes in the light-harvesting antenna network. Here, Engel proposes to use two-dimensional electronic spectroscopy, a tool capable of providing ultrafast time resolution as well as frequency resolution to probe cyanobacterial light-harvesting in vivo. Using varying laser powers and light conditions, he seeks to probe how light moves through the antenna complexes and how that pattern changes as the organisms respond to differing light conditions. The goal of this project is to map energy transfer in cyanobacteria and isolate design principles and mechanisms of photoprotection that may be applicable to synthetic systems in the future.
Rivers, Eng, and Wang's project is entitled, "Development of X-ray Tomography for Subsurface Rock and Fluid Studies."
Public abstract provided by the Department of Energy:
This project seeks to make significant developments in the x-ray microtomography capabilities at GSECARS for studying rock/fluid interactions under subsurface conditions. The conditions we will be able to simulate while doing high-resolution imaging include those important for oil and gas extraction, for CO2 sequestration, and for understanding shallow earthquakes. We will enable a wide community of scientists to rapidly obtain high-resolution images in complex sample environments vital to understanding earth’s subsurface environment.
We will design and fabricate a sample stage capable of loads greater than 25 kg, allowing us to employ much more complex sample environments than we have been able to use in the past. This stage will have sub-micron errors for positioning and rotation, permitting very high resolution imaging. We plan to construct a triaxial deformation cell capable of confining pressures up to 100 MPa, axial loads to 200 MPa, while maintaining fluid flow and temperatures up to 250 °C. We will optimize our imaging system to achieve sub-micron resolution, greatly improving the ability to image small pores and study reactions taking place in them, capabilities that are critical to understanding the behaviors of complex, energy-relevant fluids such as wet supercritical CO2 and hydrocarbons. For virtually all microtomography experiments, data reconstruction and analysis is the rate limiting step between measurement and discovery. By building new analysis tools into existing software frameworks we will transform the speed at which important problems can be solved. At the same time, we will make both our data collection and analysis software easy to use, and thus accessible to a wide community of geoscientists, including the developing next generation, further expanding the range of problems that can be solved.
Expanding the range of pressure, temperature and stress conditions that can be probed, and maximizing the speed at which fluid rock interactions can be studied, will lead to new, high-level views of mineral-fluid chemical systematics, enabling broad predictive capabilities for understanding grain fracturing, porosity and fluid flow, as well as mineral dissolution and growth mechanisms. These new initiatives at elevated pressures and confined fluids will allow us to obtain important insight on macroscale subsurface phenomena critical to energy security, including fracture propagation in rock, energy resource management, and contaminant sequestration at the sub-micron scale.