Examinando por Materia "Air pollution"

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    Assessing the effects of Multivariate Functional outlier identification and sample robustification on identifying critical PM2.5 air pollution episodes in Medellín, Colombia
    (Universidad EAFIT, 2022) Roldán Alzate, Luis Miguel; Zuluaga Díaz, Francisco Iván
    Identification of critical episodes of environmental pollution, both as a outlier identification problem and as a classification problem, is a usual application of multivariate functional data analysis. This article addresses the effects of robustifying multivariate functional samples on the identification of critical pollution episodes in Medellín, Colombia. To do so, it compares 18 depth-based outlier identification methods and highlights the best options in terms of precision through simulation. It then applies the two methods with the best performance to robustify a real dataset of air pollution (PM2.5 concentration) in the Metropolitan Area of Medellín, Colombia and compares the effects of robustifying the samples on the accuracy of supervised classification through the multivariate functional DD-classifier. Our results show that 10 out of 20 methods revised perform better in at least one kind outliers. Nevertheless, no clear positive effects of robustification were identified with the real dataset.
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    Captura de material particulado 1, 2.5 y 10 micras, con el uso de microalgas en fotobiorreactores exteriores
    (Universidad EAFIT, 2020) Mazo Zapata, Santiago; Miranda Parra, Alejandra María; Miranda Parra, Alejandra María
    Particulate matter (PM), made up of a variety of organic and inorganic substances, is found to be harmful to human health. Due to its small size, this combination of substances can enter the body by the respiratory route and cause all kinds of related diseases, such as lung cancer, trachea, esophagus. In addition to this, the 1 micron particles can enter the circulatory system and cause associated problems such as stroke and cardiovascular damage. As a result of this, especially in the mainly affected cities, such as Medellín, they will come looking for methods to deal with this problem, suggesting the use of cutting-edge technology to try to largely solve PM contamination, however, the contributions that are They have made an impact on closed spaces, without identifying that they can be very expensive to maintain, on the other hand, a level outside the city or in outdoor conditions. The use of technology has been very low, and containment measures translate into social and mobility strategies such as spike and plate extension. In this study, the use of technology in outdoor conditions is proposed, through the use of photobioreactors and microalgae to evaluate the capture potential that these microorganisms have in the capture of this PM and how it is possible to extrapolate it as a future solution to use it in The city of Medellín. As a conclusion of the experiment, it was found that the Scenedesmus Obliquus ATCC 457 microalgae (S. Obliquss ATCC 457) could grow up to 1.52 g / L and retain up to 61.07% of PM 1, 65.45% of PM 2.5 and 87.01% of PM 10.
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    Preliminary geochemical study of thermal waters at the Puracé volcano system (South Western Colombia): An approximation for geothermal exploration
    (Universidad Industrial de Santander, 2018-01-01) Gómez-Díaz E.; Marin-Cerón M.I.; Gómez-Díaz E.; Marin-Cerón M.I.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y Tectónica
    The Puracé Volcano is located in the Cauca department, SW of Colombia, along the Coconucos volcanic chain. This volcano is an interesting target for geothermal exploration, because it is a young caldera-type volcano, with thermal activity (e.g. hot springs and fumaroles). Using hydro-geochemical analyses of hot springs, we determine the type of water, origin and relation with the geothermal system, reservoir temperature, mixing process and finally the potential areas for future exploration. The analyzed water-types are bicarbonate, dilutechloride, sulphate-chloride, acid-sulphate and heated steam-acid sulfated. The conservative elements, allow to identify the correlation between different springs and to infer commune sources. Moreover, the applied solutes geothermometers for each suitable thermal-water group were used to estimate the reservoir temperature. The Silica geothermometers resulted within a range of 120°C -170°C while those the Cation geothermometers are above these temperatures reflecting values from 160°C to 220°C. However, the Cation geothermometer of low temperature clearly identify another zone of lower temperature. Mixing and recharge processes, were identified through of stable isotopes. Finally, the preliminary geothermal model shows two zones of high enthalpy system ( > 150°C). © 2018, Boletín de Geología.