Examinando por Materia "Chlorine compounds"
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Ítem The electrochemical elimination of coliforms from water using BBD/Ti or graphite anodes: A comparative study(International Water Association Publishing, 2018-04-01) Gil Pavas, E.; Arbelaez, Paula Eliana; Medina, J.; Dobrosz-Gómez, I.; Angel Gomez-Garcia, Miguel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosThe elimination of total and fecal coliforms, from raw surface water, was carried out by electrochemical oxidation using either boron doped diamond (BDD/Ti) or graphite (GP) anodes, in a chloride-free medium. The optimal values of the operation parameters, maximizing the coliform elimination percentage, were determined using statistical experimental design. The current density ( j: 2-20 mA/cm2), the conductivity (s: 500-900 µS/cm) and the anode materials (An) were considered as variables to perform the Box-Behnken experimental design together with the response surface methodology analysis for optimization. The statistical analysis indicated that, in the evaluated range, the disinfection efficiency increased with an increase in j and decreased with an increase in s. The following optimal conditions for the elimination of total and fecal coliforms were found: j: 10 mA/cm2, s: 500 µS/cm and BDD/Ti used as anode material. The BDD/Ti electrode let to achieve complete coliform elimination after ca. 20 min of reaction while the GP one needed ca. 27 min. In water treated with both BDD/Ti and GP anode, after 7 days, any coliforms growth was observed. As a result of the oxidation process, the total organic carbon and nitrite concentration decreased while nitrate concentration increased. © IWA Publishing 2018.Ítem The electrochemical elimination of coliforms from water using BBD/Ti or graphite anodes: A comparative study(International Water Association Publishing, 2018-04-01) Gil Pavas, E.; Arbelaez, Paula Eliana; Medina, J.; Dobrosz-Gómez, I.; Angel Gomez-Garcia, Miguel; Gil Pavas, E.; Arbelaez, Paula Eliana; Medina, J.; Dobrosz-Gómez, I.; Angel Gomez-Garcia, Miguel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)The elimination of total and fecal coliforms, from raw surface water, was carried out by electrochemical oxidation using either boron doped diamond (BDD/Ti) or graphite (GP) anodes, in a chloride-free medium. The optimal values of the operation parameters, maximizing the coliform elimination percentage, were determined using statistical experimental design. The current density ( j: 2-20 mA/cm2), the conductivity (s: 500-900 µS/cm) and the anode materials (An) were considered as variables to perform the Box-Behnken experimental design together with the response surface methodology analysis for optimization. The statistical analysis indicated that, in the evaluated range, the disinfection efficiency increased with an increase in j and decreased with an increase in s. The following optimal conditions for the elimination of total and fecal coliforms were found: j: 10 mA/cm2, s: 500 µS/cm and BDD/Ti used as anode material. The BDD/Ti electrode let to achieve complete coliform elimination after ca. 20 min of reaction while the GP one needed ca. 27 min. In water treated with both BDD/Ti and GP anode, after 7 days, any coliforms growth was observed. As a result of the oxidation process, the total organic carbon and nitrite concentration decreased while nitrate concentration increased. © IWA Publishing 2018.Ítem Electronic and Topological Analysis for New Phases of Chromium Nitride(WILEY-V C H VERLAG GMBH, 2018-01-01) Marin-Suarez, Marco; Alzate-Vargas, Leidy L.; David, Jorge; Arroyave-Franco, Mauricio; Velez, Mario E.; Universidad EAFIT. Departamento de Ciencias Básicas; Electromagnetismo Aplicado (Gema)Chromium nitride (CrN) in its NaCl-type phase has been widely studied through density functional theory (DFT) in order to analyze its electronic properties. By the means of DFT with the Becke's three parameter Lee-Yang-Parr (B3LYP) hybrid functional, the same stoichiometry is studied in two unreported hypothetical phases in addition to the nonsynthesized and previously reported zinc-blende-type phase. The cohesive energy of every structure is calculated, and the analysis of this quantity indicated that all crystals are stable and that there is an unreported phase more stable than the synthesized one. The calculated electronic dispersion relation and density of electronic states allowed for the determination that these three phases have a conducting behavior. The symmetry of some bands is determined as a result of the crystal field splitting for chromium d states. The topology of the electron density was studied in order to determine its properties at bond critical points (BCPs). The form of the Laplacian of the density and its gradient trajectories allowed to locate ring critical points in these structures. From these calculations, it is concluded that all three phases are ionic crystals. The synthesized NaCl-type phase is studied in order to compare and confirm the results. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimÍtem Geoparques en Colombia: Una estrategia para la aplicación de los objetivos de desarrollo sostenible - caso: Magdalena Medio antioqueño(Universidad Industrial de Santander, 2019-01-01) Tavera-Escobar M.Á.; Álvarez-Ramírez D.; Tavera-Escobar M.Á.; Álvarez-Ramírez D.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaThe GGN (Global Geopark Network) is a figure for the natural conservation in the rural territory through the protection, education and apropiation forms of geological resources with international importance, in conjunction with the natural and cultural context of certain sites. This work highlight methodologically the rol of the geoparks in this country and its close relationship with the Sustainable Development Goals. A case of study is proposed in Magdalena Medio antioqueño where the geological science is associated whit the economic, scientific and social development of the region by geoturism. © 2018, Universidad Industrial de Santander.Ítem Stratifying the potential local transmission of Zika in municipalities of Antioquia, Colombia(Blackwell Publishing Ltd, 2017-10-01) Ospina J.; Hincapie-Palacio D.; Ochoa J.; Molina A.; Rúa G.; Pájaro D.; Arrubla M.; Almanza R.; Paredes M.; Mubayi A.; Ospina J.; Hincapie-Palacio D.; Ochoa J.; Molina A.; Rúa G.; Pájaro D.; Arrubla M.; Almanza R.; Paredes M.; Mubayi A.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónOBJECTIVE To stratify and understand the potential transmission processes of Zika virus in Colombia, in order to effectively address the efforts on surveillance and disease control. METHODS We compare R-0 of Zika for municipalities based on data from the regional surveillance system of Antioquia, Colombia. The basic reproduction number (R-0) and its 95% confidence intervals were estimated from an SIR model with implicit vector dynamics, in terms of recovered individuals in each time unit, using an approximate solution. These parameters were estimated fitting the solution of the model to the daily cumulative frequency of each Zika case according to symptoms onset date relative to the index case reported to the local surveillance system. RESULTS R-0 was estimated for 20 municipalities with a median of 30 000 inhabitants, all located less than 2200 m above sea level. The reported cases ranged from 17 to 347 between these municipalities within 4 months (January to April of 2016). The results suggest that 15 municipalities had a high transmission potential (R-0 > 1), whereas in five municipality transmissions were potentially not sustaining (R-0 < 1), although the upper bound of the confidence interval of the R-0 for 3 of these 5 was greater than one, indicating the possibility of an outbreak later on. CONCLUSION The study identified high-risk municipalities (R-0 > 1) and provide a technique to optimise surveillance and control of Zika. Health authorities should promote the collection, analysis, modelling and sharing of anonymous data onto individual cases to estimate R-0.