42 research outputs found

    Dinámica de publicación de la Universidad del Valle

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    Uno de los objetivos de la comunidad universitaria, es dar a conocer los resultados de sus actividades misionales, en particular la investigación, y una de las formas de llevarlo a cabo, es a través de las publicaciones, por lo anterior, el reto es aumentar el nivel de publicaciones en revistas de alto impacto y alta visibilidad

    Las perspectivas desde las diferentes disciplinas para la investigación, la educación y la innovación en tiempos de crisis.

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    El SARS-CoV-2 modificó la forma de relacionarnos a todo nivel, desde el familiar hasta el institucional. La humanidad se ha visto afectada en épocas anteriores por pandemias y virus, sin embargo, ninguna en el pasado reciente había tenido tanto impacto de manera importante y generalizada para el mundo entero. Es así como esta coyuntura ha llevado a que se modifiquen las expectativas y metas personales, profesionales e institucionales. En consideración de lo anterior se puede entonces afirmar que quienes participan del Sistema Nacional de Ciencia y Tecnología e Innovación, tampoco son ajenos a esta situación y son conscientes que los indicadores que miden su nivel de desempeño se van a ver modificados durante este 2020 y por supuesto en los próximos años

    Perfil de la revista Ingeniería y Competitividad : modelos de medición y estadísticas.

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    La revista Ingeniería y Competitividad de la facultad de ingeniería de la Universidad del Valle inicio su publicación en el año 1997 con seis artículos, los cuales están disponibles en su página web (https://revistaingenieria.univalle.edu.co/index.php/ingenieria_y_competitividad/issue/view/259). A lo largo de su historia, la revista ha crecido en importancia y ha recorrido diferentes etapas de acuerdo a los modelos de medición establecidos por Publindex, así: 2005 a 2007 Categoría C; 2008 Categoría B; 2009 a 2018 Categoría A2; 2019 a 2020 Categoría C y 2021 Categoría B. El cambio de categoría implica retos pues el número de solicitudes de artículos se incrementa o disminuye de manera critica, lo que se traduce en dificultades en la edición de los números de la revista. La figura 1 muestra la distribución de artículos publicados desde el 2012. Se puede observar que durante los periodos de categorías superior el volumen de publicaciones es más alto, a partir del 2018 se ha mantenido estable el número de artículos, se prevé un aumento sustancial para el 2021

    Modeling the photocatalytic mineralization in water of commercial formulation of estrogens 17-β estradiol (E2) and nomegestrol acetate in contraceptive pills in a solar powered compound parabolic collector

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    Endocrine disruptors in water are contaminants of emerging concern due to the potential risks they pose to the environment and to the aquatic ecosystems. In this study, a solar photocatalytic treatment process in a pilot-scale compound parabolic collector (CPC) was used to remove commercial estradiol formulations (17-β estradiol and nomegestrol acetate) from water. Photolysis alone degraded up to 50% of estradiol and removed 11% of the total organic carbon (TOC). In contrast, solar photocatalysis degraded up to 57% of estrogens and the TOC removal was 31%, with 0.6 g/L of catalyst load (TiO2 Aeroxide P-25) and 213.6 ppm of TOC as initial concentration of the commercial estradiols formulation. The adsorption of estrogens over the catalyst was insignificant and was modeled by the Langmuir isotherm. The TOC removal via photocatalysis in the photoreactor was modeled considering the reactor fluid-dynamics, the radiation field, the estrogens mass balance, and a modified Langmuir-Hinshelwood rate law, that was expressed in terms of the rate of photon adsorption. The optimum removal of the estrogens and TOC was achieved at a catalyst concentration of 0.4 g/L in 29 mm diameter tubular CPC reactors which approached the optimum catalyst concentration and optical thickness determined from the modeling of the absorption of solar radiation in the CPC, by the six-flux absorption-scattering model (SFM)

    Estudio exploratorio en el tratamiento de vinazas mediante fotocatálisis solar homogénea en un reactor de película descendente

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    En este estudio se realizaron pruebas a escala laboratorio y piloto de degradación fotocatalítica de vinaza, utilizando reactivo Fenton como un posible método alternativo para la reducción de su carga orgánica. Se evaluaron los efectos de variables como pH inicial, relación [H2O2]/[Fe+2] y [H2O2]; utilizando como variables de respuesta la remoción de Carbono Orgánico Total (COT), sólidos totales y turbidez. Para los ensayos a escala piloto, se utilizó un reactor de película descendente, radiación solar natural como fuente de fotones, peróxido de hidrógeno comercial al 50% y sulfato de hierro. Se alcanzaron disminuciones de COT de 12,53%, a relación de [H2O2]/[Fe+2]=15, [H2O2]=0,5 mol/ l y pH natural, con vinaza concentrada. Para los sólidos totales y turbidez, se presentaron aumentos hasta de 19,79% y 16,95% respectivamente, a las mismas condiciones y relación [H2O2]/[Fe+2]=20. La variable que tuvo mayor influencia sobre el proceso fue la relación [H2O2]/[Fe+2]

    Impact of photocatalyst optical properties on the efficiency of solar photocatalytic reactors rationalized by the concepts of initial rate of photon absorption (IRPA) dimensionless boundary layer of photon absorption and apparent optical thickness

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    The concepts of “initial rate of photon absorption” (IRPA), “dimensionless boundary layer of photon absorption” and “apparent optical thickness (τapp)” are presented to evaluate the radiative transfer phenomena in solar, slurry, planar, photocatalytic reactors. The radiation field produced by suspensions of TiO2 and goethite, two photocatalysts with profoundly different optical properties used in heterogenous photocatalysis and heterogeneous photo-assisted Fenton reactions, was determined by the six-flux radiation absorption-scattering model coupled to the Henyey-Greenstein scattering phase function (SFM-HG). The concept of IRPA, defined by the differentiation at the local volumetric rate of photon absorption (LVRPA) at the reactor window boundary, is proposed as a new approach to determine the impact of catalyst loading and optical properties on the extinction of light inside a photoreactor. The IRPA showed that the extinction of light follows a second order dependency on the photocatalyst concentration while the impact of the optical properties can be expressed by a decoupled function (Ψ function). The Ψ function increased with photocatalyst concentration and approached a maximum at the same optimal photocatalyst concentration determined from the analysis of the total rate of photon absorption (TRPA) in the reactor. The analysis of TRPA and boundary layer of photon absorption redefined here in dimensionless form, as a function of τapp, determined that the most efficient rate of radiation absorption in solar powered planar reactors occurs at τapp = 4.1–4.4, with approximately 10% of the reactor width under darkness. τapp is a similarity dimensionless parameter exclusively derived from the SFM approach, which clusters the effects of photocatalyst loading, reactor dimension and photocatalyst optical properties, providing an ideal parameter for designing and scaling photocatalytic reactors operated with any kind of photocatalytic material

    Protocolo para el mantenimiento de cepas y escalamiento en la producción de microalgas de interés industrial.

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    Scenedesmus sp. & Chlorella sp., son dos microalgas aisladas de termales localizados en Norte de Santander, las cuales son estudiadas con el fin de explorar su potencial biotecnológico. El presente trabajo tuvo como objetivo diseñar un protocolo mediante la evaluación de dos factores, el efecto de stress por radiación lumínica y el tiempo de incubación mediante el escalonamiento del cultivo desde Caja Petri en Medio de cultivo Bold basal (BBM) con un tiempo de incubación de 15 días a un tubo Falcon de 15 mL con 10 mL de medio líquido y fue en esta parte donde se evaluó el parámetro de tiempo de incubación, por último fue escalado a un fotobioreactor utilizando un volumen de trabajo de 200 mL, empleando el mismo medio de cultivo con el fin de analizar las variables estudiadas se empleó un diseño de experimentos de superficie compuesto, central, no factorial en el software STATISTICA 7.0, a partir del cual se obtuvo una ecuación lineal que permitio determinar el tiempo de incubación y fotoperiodo óptimo para una mayor producción de microalgas y como resultados se determinó que en la microalga Scenedesmus sp. los dos factores influyen en la producción de carotenoides; para Chlorella sp. no influye el tiempo de incubación y el fotoperiodo es fundamental en la producción de estos metabolitos

    Photocatalytic degradation of cobalt cyanocomplexes in a novel LED photoreactor using TiO2 supported on borosilicate sheets: A new perspective for mining wastewater treatment

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    The photocatalytic degradation of hexacyanocobaltate ion ([Co(CN)6]3−) by TiO2 supported on borosilicate sheets was studied in a novel photoreactor operated under UVA-LEDs irradiation. The presence and absence of O2 during the process, and the reuse of the TiO2-impregnated sheets were evaluated. The semiconductor was supported by the dip-coating method, and the influence of g TiO2/g Methanol (MetOH) ratio in the suspension and substrate roughness modification were evaluated in the detachment percentage and adherence of TiO2. The highest semiconductor detachment percentage was obtained at 0.36 g TiO2/g MetOH ratio. Besides, it was determined that for the ten layers supported, the substrate roughness modification does not influence the detachment of TiO2. In the first photocatalytic tests, the results show that a better degradation performance was achieved by direct photolysis than photocatalysis according to the higher concentration of CN− released from the cyanocomplex. However, a decrease in the concentration of cobalt in solution was not observed. When the sheets were reused, a decrease of 10% in the concentration of cobalt was achieved, and 14% of CN− was released from the cyanocomplex. This was attributed to the formation of microchannels, hollows amongst other imperfections that increase the surface area and active sites of the coating when TiO2 peels off. The simplified kinetics analysis shows that for UV + O2 (oxic environment) UV + N2 (anoxic environment) similar kinetic parameters were obtained, indicating that both processes follow the same homogeneous pathway in the degradation of [Co(CN)6]3−. However, for the UV + TiO2+O2 and UV + TiO2+N2, their different kinetic parameters suggest a non-homogeneous degradation mechanism with different pathways induced by the presence or absence of O2

    Coupling the six flux absorption-scattering model to the Henyey-Greenstein scattering phase function: Evaluation and optimization of radiation absorption in solar heterogeneous photoreactors

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    © 2016 Elsevier B.V.Robust and practical models describing the radiation field in heterogeneous photocatalytic systems, used in emerging environmental, photochemical and renewable energy applications, are fundamental for the further development of these technologies. The six-flux radiation absorption-scattering model (SFM) has shown to be particularly suitable for the modeling of the radiation field in solar pilot-plant photoreactors. In this study, the SFM was coupled to the Henyey-Greenstein (HG) scattering phase function in order to assemble the model with a more accurate description of the scattering phenomenon provided by this phase function. This new version of SFM, named as SFM-HG, was developed through fitting the Local Volumetric Rate of Photon Absorption (LVRPA) determined in a flat photoreactor to the "pseudo-experimental" LVRPA calculated by a Monte Carlo (MC) approach, which included the HG expression. As a result, simple mathematical correlations describing the SFM-HG scattering probabilities as function of the HG scattering parameter were determined. The SFM-HG was validated through a comparison with the MC model predictions of the Total Rate of Photon Absorption (TRPA) in the slab photoreactor. A RMSE% of approximately 5% demonstrated satisfactory agreement between the models. The SFM-HG was further applied to evaluate the impact of selected scattering phase functions on the absorption of radiation in solar photoreactors, operated with commercial TiO2 photocatalyst. The results have established that, the apparent optical thickness, τapp (or τapp,max for tubes) a parameter derived from the SFM approach, is the most appropriate for the design and optimization of photocatalytic reactors. This parameter is insensitive to scattering albedos and phase functions. CPC, tubular and flat-plate photoreactors should be designed with τapp,max = 12, τapp,max = 7 and τapp = 4.5 respectively

    A novel prototype offset multi tubular photoreactor (OMTP) for solar photocatalytic degradation of water contaminants

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    © 2018 Elsevier B.V. The design and operation of a new solar photoreactor prototype named Offset Multi Tubular Photoreactor (OMTP) is presented. The OMTP advances over the compound parabolic collector (CPC) photoreactor, which is one of the most efficient design for large-scale solar detoxification of water and wastewater. The OMTP design is based on a simple modification of the common CPC and included a supplementary set of tubes in the space occupied by the axes of intersection of the CPC reflective involutes. This new reactor configuration increased the irradiated reactor volume by 79% and the fluid residence time by up to 1.8-fold in comparison to the CPC, for the same solar irradiated area (footprint). The model parameters used for comparing and scaling the OMPT and CPC were β (reactor volume/total volume), α (area of absorption/total volume), α g (physical area/total volume), degradation efficiency η α per unit area, and the operating volume. The total solar energy absorbed in the reactors (1.74 m 2 footprint) was 15.17 W for the CPC and 21.86 W for the OMTP, which represents an overall gain of 44% for the latter. The performance of the OMTP and CPC were compared at the same value of solar exposure, β of 0.3 with optimal photocatalyst loading of 0.25 g/L titanium dioxide (TiO 2 P25). The degradation efficiencies of methylene blue, dichloroacetic acid, 4-chlorophenol (120 ppm initial concentration) in the OMTP were up to 81%, 125%, 118% and 242% higher, respectively, in comparison to the CPC after 8000 J/m 2 of accumulated solar energy. The OMTP should outperform the CPC in environmental and renewable energy applications of solar heterogeneous photocatalysis
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