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Tuttle Creek Dam in Manhattan, Kansas was found to be seismically deficient. Cement-bentonite slurry walls were used to remediate the dam. We use the EFFC DFI Carbon Calculator to calculate the carbon footprint of the cement- bentonite slurry walls, as well as the carbon footprint of an alternative remediation option, stone columns. The cement-bentonite slurry walls resulted in a GWP 100 of 71,000 tonnes CO2 equivalent, while the stone columns resulted in a GWP 100 of 3,900 tonnes CO2 equivalent, a significant difference even when considering the uncertainties in life cycle modeling. The Carbon Calculator is a simple tool for quantifying the carbon footprint of different geotechnical engineering techniques.

The optical absorption properties of LaFeO(3) (LFO) have been calculated using density functional theory and experimentally measured from several high quality epitaxial films using variable angle spectroscopic ellipsometry. We have analyzed the calculated absorption spectrum using different Tauc models and find the model based on a direct-forbidden transition gives the best agreement with the ab initio band gap energies and band dispersions. We have applied this model to the experimental data and determine the band gap of epitaxial LFO to be ∼2.34 eV, with a slight dependence on strain state. This approach has also been used to analyze the higher indirect transition at ∼3.4 eV. Temperature dependent ellipsometry measurements further confirm our theoretical analysis of the nature of the transitions. This works helps to provide a general approach for accurate determination of band gaps and transition energies in complex oxide materials.

We evaluate the environmental life cycle performance of the use of recycled materials for sustainable slope engineering. Crushed glass dredged material (CG-DM) blends, (in proportions of 20/80, 50/50, and 80/20, with crushed glass reported first) for embankment fill material were compared to primary fill materials for six life cycle impact assessment (LCIA) metrics: cumulative energy demand, 100-year global warming potential (GWP), and air quality indicators nitrogen oxides (NOx), sulfur dioxides (SOx), carbon dioxide (CO 2 ) and particulate matter (PM). Results suggest that life cycle energy, GWP, CO 2 , and SOx decline with use of recycled materials for embankment fills; however, due to increased processing at the site for the CG-DM blends, particulate matter surpasses primary-fill embankments studied herein. With respect to NOx emissions, the primary fill embankment and the 80/20 CG-DM blend have about the same amount, followed by the 50/50 blend and the 20/80 blend, in descending value, respectively. Results from this work suggest that recycled content in fill materials is beneficial to reducing energy resource consumption, GWP, CO 2 , SOx and NOx (except for the 80/20 blend); however, there may be increased health risks due to increased emissions of criteria pollutant particulate matter. Overall, this study demonstrates the importance of quantifying the life cycle benefits of recycled and marginal materials as an important step towards understanding the environmental tradeoffs of their increased use in construction.