Browsing by Author "Faundez, Rodrigo"

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    An Improved Synthesis of 3,6-Dihydro-as-indacene
    (2021) RDibdalli, Yuvaraja; Faundez, Rodrigo; Preite, Marcelo; Molins, Elies; Chavez, Ivonne; Amshumali, Mungalimane K.; Morales-Verdejo, Cesar; Manriquez, Juan M.
    This contribution describes an updated synthetic route to 3,6-dihydro-as-indacene along with full characterization of all intermediates. The title compound is prepared by Mannich condensation of 2-methylfuran with formaldehyde and dimethylamine hydrochloride, quaternization of the resulting amine with methyl iodide, and conversion into the ammonium hydroxide salt by treatment with silver oxide in water. Subsequent Hoffmann elimination and [6,6]-cycloaddition through pyrolysis produces a furanocyclophane, which after photooxidation, intramolecular cycloaddition, and dehydration with sodium carbonate affords 2,3,6,7-tetrahydro-1,8-dione-as-indacene. Reduction of this diketone gives a mixture of alcohols, which after dehydration under slightly basic or acidic conditions produces 3,6-dihydro-as-indacene. The structure is confirmed by X-ray diffraction, and all intermediates are characterized by means of H-1 and C-13 NMR spectroscopy.
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    Using social cartographies for the calibration of two-dimensional hydraulic flood models
    (2024) Alarcon, Benjamin; Saenger, Vicente; Guerra, Maricarmen; Faundez, Rodrigo; Link, Felipe; Carrasco, Juan Antonio; Link, Oscar
    Accurate numerical simulations of floods provide precise hazard estimations and can improve risk management strategies. Unfortunately, flood events of extraordinary magnitude -needed for risk assessment- are rare and difficult to measure. Hence, numerical models are typically calibrated and validated using a few measured scenarios of moderate magnitudes. Flood social cartography, a participatory mapping method, identifies historically flood-prone areas based on the residents' experience and knowledge. This research proposes using social cartographies to calibrate and validate hydraulic flood models. A numerical flood simulation model of the lower reach of the unregulated Carampangue River, Chile, was calibrated and validated using available information from gauges, satellite images, and social cartographies for the towns of Arauco and Ramadillas. The discharge magnitude of floods recorded in the social cartographies was determined. The quality of both models, calibrated with gauge data and with social cartography flood maps, was determined in each case by comparing computations with depth gauge data and satellite images through the root mean square error and the critical success index. Results show that social cartography participants recognized flooded areas corresponding to a discharge with a return period of 35 years. The calibration with social cartographies delivered a set of Manning's roughness coefficients similar to those obtained using gauge data. The validation cases show that water depth and the extension of floods computed with the model calibrated using social cartographies is comparable to that computed using gauge data in the calibration process. RMSE from both calibrated models is of order 0.1 m. Consequently, the social cartography of floods constitutes a useful data source of extreme flood scenarios for calibrating and validating numerical flood models.