Examinando por Materia "NATURAL RESOURCES: WATER, MINERALS, BIODIVERSITY"
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Publicación Acceso abierto Ajuste de curvas mediante métodos no paramétricos para estudiar el comportamiento de contaminación del aire por material particulado PM10(2013-12-16) Reina, J. (Jhovana); Olaya, J. (Javier)One of the main air pollutants is the particulate matter whose aerodynamic diameter is less than 10 micrometers, usually referred as PM10. It is a fact that the PM10 behavior in the air varies in an irregular way, and also in a temporal way in the atmosphere, mainly due to human activities, to unstable atmospheric conditions, and to meteorological phenomena. Our main purpose is to characterize through a nonparametric smooth model the PM10 daily behavior, taking into account the day of the week, and the precipitation levels. We illustrate the model using records on PM10 contamination, as well as on data on rain precipitation in the north side of Cali, Colombia. We estimate daily typical curves of the PM10 behavior using kernel and spline estimators. We processed these data using the free distribution statistical software R. The estimated curves allow us to observe a PM10 unimodal behavior during the morning hours, which varies from one day to another and from rainy to non-rainy days. The fitted models allow a robust characterization of the PM10 daily behavior, considering heteroscedastic observations on a multiple response per design point scenario.Publicación Acceso abierto Análisis de sensibilidad espacial de un modelo hidrodinámico del embalse Punchiná (Antioquia)(2013-12-17) Escobar, C. A. (Carlos Alejandro)This paper presents a methodology to assess explicitly the optimal value of the numerical parameters in a hydrodynamic model, such as the grid resolution (horizontal and vertical direction) and the calculation time interval. The methodology is based on a cost-benefit analysis which seeks a desirable balance between the quality of the numerical solution and the required computational time. The spatial nature of the sensitivity analysis presented allows us to determine in each calculation grid cell the alteration of the numerical solution due to changes in the numerical or physical parameters in the model. According to this, it was possible to determine within the Punchiná reservoir where and to what extent are relevant the grid resolution, the time interval, the bed roughness, and the eddy viscosity coefficient.Publicación Acceso abierto Análisis de umbrales empíricos de lluvia para el pronóstico de movimientos en masa en el Valle de Aburrá, Colombia(2013-12-17) Aristizábal, E. (Edier); Gonzalez, T. (Tommy); Montoya, Juan David; Vélez, Jaime Ignacio; Martínez, H. (Hernán); Guerra, AlexánderMass movements are the product of a progressive reduction of strength of slope geomaterials by human actions or natural processes, such as weathering, and triggered by external factors like rainfall or earthquakes. These events have demonstrated throughout history its destructive capacity, causing huge human and economic losses, especially in tropical and mountainous terrains, such as the Aburrá Valley. For this reason new studies on rainfall forecasting, real-time monitoring and the definition of critical rainfall thresholds have become essential tools for the implementation of early warning systems.Publicación Acceso abierto Análisis del conocimiento en la relación agua-suelo-vegetación para el Departamento de Antioquia(2014-05-06) Villegas-Palacio, J. C. (Juan Camilo)This paper presents a compilation of the main results obtained in the Antioquia Department about the interactions between water, soil, and vegetation. Although there is an advanced knowledge in some aspects of this relationship, it is necessary to go deep into other ones which have not been approached in an integral manner. Likewise, it is necessary to enhance the research in order to cover the diversity of ecosystems of the Department.Publicación Acceso abierto Annual and diurnal cycles of the inverse relation between plant transpiration and carbon sequestration(2014-05-09) Moreno-Ramírez, H. A. (Hernán Alonso)El conocimiento de los ciclos biogeoquímicos y, en especial, de los balances de carbono es clave para la validación de los modelos de cambio global para el presente y el futuro cercano. Como consecuencia, en el mundo se estudian las fuentes y los sumideros de carbono. Uno de esos sumideros es la vegetación del planeta, que involucra los procesos de respiración y fotosíntesis y cuyo comportamiento se empieza a estudiar. Las tasas de captura del carbono están muy ligadas a la transpiración mediante un proceso de difusión molecular en los estomas, que puede registrarse por un sistema micrometeorológico de eddy covarianza. Este artículo explora los ciclos anuales y diurnos de los flujos netos de CO2 y calor latente de seis ecosistemas diferentes. Se desarrollan diversos análisis de escala temporal, basados en la física de la transpiración, y se halla una relación cuasilineal entre los flujos netos de calor latente y CO2, más fuerte en las áreas con mayor cobertura vegetal. La temporada del monzón norteamericano incrementa la captura de carbono y la relación entre la evapotranspiración y el intercambio de gas carbónico se mantiene en las diferentes escalas temporales analizadas (horas, días, meses).Publicación Acceso abierto Aplicación de los SIG para la evaluación del estado de conservación del hábitat del Paujil De Pico Azul Crax Alberti (Aves: Cracidae) en el Nororiente de Antioquia, Colombia(2014-05-07) Molina-Giraldo, A. M. (Adriana María); Barros-Martínez, J. F. (Juan Fernando)The blue-billed curassow, Crax alberti, is a critically endangered endemic bird from the northern part of Colombia, mainly subjected to habitat loss and subsistence hunting. Geographic Information Systems (GIS) were used to compare the conservation status of forested areas, habitat of the blue-billed curassow, in 15 municipalities of the northeastern region of Antioquia for two different time periods (1986 and 2002). The developed application using digital cartography, allowed the classification of eight zones defined for the study area in order to analyze conservation priorities. Recommendations are made as well for future applications of GIS as a management tool for threatened species in Colombia.Publicación Acceso abierto Calibración e implementación del modelo MG para la estimación de caudales máximos en Colombia(2013-11-19) Duque, A. F. (Andrés Felipe); Restrepo, C. (Carlos)The purpose of this paper is calibrate a model for estimating peak flows adapted to the hydrological, geomorphological, and vegetation cover in Colombian basins. For this reason, the parameters of probabilistic MG model were calibrated for the whole territory of Colombia, its major geographic regions and hydrologically homogeneous subregions. To obtain the analytical equations of the MG model, historical records of peak flows in 277 water level recorder stations in Colombian were used. The obtained results by applying the MG calibrated model and other commonly used methods to estimate peak flows were compared, and very similar values were found. The MG model calibrated in this work is shown as a viable option for estimating peak flows in basins with scarce data in Colombia.Publicación Acceso abierto Calidad del agua de las Quebradas La Cristalina y La Risaralda, San Luis, Antioquia(2014-05-12) Arango-Jaramillo, M. C. (María Cecilia); Álvarez-Arango, L. F. (Luisa Fernanda); Arango-Rojas, G. A. (Gloria Alexandra); Torres, O. E. (Orlando Elí); Monsalve-Ríos, A. J. (Asmed de Jesús)The streams La Cristalina and La Risaralda are the water sources for the urban area of the Municipality of San Luis, Antioquia. The intention of this study was to develop a map of water quality that serves as base as comparison of the evolution of the streams and allows the high-priority destination of the resources of the Municipality in the improvement of those more critical sections. In order to determine the quality of the water, parameters and some characteristics of the stream that can alter the quality of the water were measured, like substrate of the bed, cover of banks, aquatic habitats, temperature, conductivity, oxygen, pH, coliforms, and aquatic macroinvertebrates. The indices calculated with base in the collected data were: BMWP, ASPT, ETP, Index of Diptera, and equity Index. With the data of the ASPT the map of water quality of both streams was elaborated. The streams are well oxygenated and the rocky conformation of its bed allows the diversity of aquatic macroinvertebrates, nevertheless, in some sections, they are subjected to contamination of domestic and farming origin, which limits their conditions of use.Publicación Acceso abierto El carbón colombiano y el modelo de Hotelling(2013-11-20) Franco, G. (Giovanni); Gallo, A. F. (Adrián Felipe); Franco, EstebanIn this paper a description of the relationship between economic thought and natural resources, especially those non-renewable, is presented. The Hotelling model is defined, with its mathematical approach and the respective graphical solution, which determines the optimal path of depletion of a non-renewable natural resource and an estimation of its market price. A general frame for the present situation and prospects for thermal coal in Colombia is the basis for the implementation of this model to this energy resource. Based on the proven reserves of thermal coal in Colombia and its demand function, time depletion and its trading price are determined.Publicación Acceso abierto Control de fasciola hepatica en el agua de consumo animal a través de filtración rápida y lenta(2013-10-28) González-Morales, C. (Carolina); Sánchez, G. A. (Gladys Adriana); Castro-Jiménez, C. C. (Camilo César); Gómez-Carmona, C. (Catalina)The bovine fasciolosis is a zoonosis caused by Fasciola hepatica transmitted by consuming water and / or vegetables contaminated with the digenea. This disease causes significant economic losses in the dairy producer regions of Antioquia. In order to remove the eggs of the parasite from water, we designed and built two filters (rapid and slow filtration), using industrial sand as filter bed (effective size 0.45-0.55 mm). A rapid filtration system was evaluated at speeds of 5 and 8 m/h for a sand bed height of 60 cm and a slow filtration system at a speed of 1.46 m/h for sand bed heights of 30 and 40 cm. The variation of effluent flow and removal efficiency of both turbidity and parasite eggs were determined during the run of each filtration. The results show that all filters operating under the described features are 100% efficient in removing the F. hepatica eggs from the water. The turbidity removal percentages were 85.5% and 79.4% for filters operating at speeds of 5 m/h and 8 m/h respectively.Publicación Acceso abierto Criterios sismológicos para seleccionar acelerogramas reales de la Red Nacional de Acelerógrafos de Colombia para su uso en análisis dinámicos(2013-11-12) Acevedo, Ana BeatrizThe use of real accelerograms as input in dynamic analysis is desirable as they provide realistic information about the nature of the strong ground motion; in addition, accelerograms capture different characteristics that can be produced by earthquakes at different locations. Colombian design code allows for the use of real accelerograms as input to time-history analysis. The horizontal component of a minimum of three different accelerograms is required by the code; all of the accelerograms must be representative of the expected ground motion at the site. In this paper the database of Colombian National Network of Accelerographs (Red Nacional de Acelerógrafos de Colombia, RNAC) is analyzed in order to assess the availability of records for different ground motion characteristics for their use as input in dynamic analysis. Groups of accelerograms that could be used as input for dynamic analysis were identified. However, if only records from the RNAC are used, it is not possible to completely cover the selection requirements specified on the Colombian design code.Publicación Acceso abierto Determinación del color del exocarpio como indicador de desarrollo fisiológico y madurez en la guayaba pera (psidium guajava cv. guayaba pera), utilizando técnicas de procesamiento digital de imágenes(2013-10-23) Castro-Camacho, J. K. (Jennifer Katiusca); Cerquera-Peña, N. E. (Néstor Enrique); Gutiérrez-Guzmán, NelsonThe colorimetric coordinates analysis of digital images in samples pear guava fruits (Psidium guajava cv. Pear guava) was performed for three times of harvest: traditional harvesting at 120 days after flowering (T1), early harvesting at 112 days after flowering (T2) and, early harvesting at 110 days after flowering (T3), the three group of samples were stored at environmental conditions at a temperature of 26 ºC and 58% of relative humidity and under refrigeration at 7.5 ºC and 85% relative humidity. For color determination two color spaces were used: RGB and CIE-L*a*b*, each of these spaces describes the color of the skin using three components that allow the comparison of its evolution during each step of postharvest. The results showed a typical evolution from deep green, freshly harvested, to light green yellowish colors. The found coordinates allow the reproduction of the colors of the evolution of ripening in printing devices configured in RGB coordinates. From the physicochemical parameters assessed, the respiration rate of the fruit is the most correlated with the change of color during the post-harvest stage.Publicación Acceso abierto Diseño de un sistema de biofiltración para la remoción de estireno(2014-05-07) Jimenez-Roldan, E. (Esteban); Villegas, A. M. (Ana María)This work was focused on developing an elimination process of styrene, an organic compound generating complex odors in air, through the design and construction of a biofiltration system, utilizing bacteria of the Pseudomona aeruginosa and Escherichia coli types stuck on a pumice stone support. Air was contaminated with styrene, in concentrations above the American Standard (TLV 40 ppm, ACGIH Worldwide, 2002), to simulate a hazardous work environment to the human health. To evaluate the efficiency of the system, the contaminated inlet air as well as the outlet flow were analyzed by taking direct styrene concentrations measurements with an organic vapor meter. Initially, the results obtained from the styrene degradation were above 55%, for a five-daily-sampling average during 10 days. This percentage was a consequence of the progressive stabilization process of the system within the first days, so the removal was low. However, average removals above 70% and punctual removals above 90% were reached after the eighth day. The pumice stone support demonstrated to be a good alternative to improve biofilm formation; the rapid micropore saturation guaranteed low adsorption of the organic compound and confirmed the elimination of styrene via biodegradation.Publicación Acceso abierto Diseño de una metodología de selección de sitios para monorrellenos de lodos papeleros(2014-05-08) Quinchía-Figueroa, A. M. (Adriana María); Irwin, S. (Susan); Uribe-Ramírez, A. M. (Ana María)The wastewater treatment at paper industry that uses recycled fibers as one of its raw materials generates a sludge rich in cellulose fibers, which once dehydrated is called “paper waste”. This waste has become an environmental problem because of its high generation rate. Although several alternatives of valorization have been studied, in Medellin none of them has been implemented on an industrial scale; the necessity is still there, that is why the land disposal of this waste appears as the most immediate way to manage it. Combined with the problem of disposition, it is the selection of the suitable site to make it, for which a methodology to be applied in the evaluation and selection of the optative sites for the disposition of remainders of paper industry was developed.Publicación Acceso abierto Efecto del incremento en la turbiedad del agua cruda sobre la eficiencia de procesos convencionales de potabilización(2013-11-15) Montoya, C. (Carolina); Loaiza, D. (Diana); Torres, P. (Patricia); Cruz, Camilo H. (Camilo Hernán); Escobar, Juan CarlosEnvironmental phenomena cause a strong impact in the variation of the quality of sources for drinking water, demanding that potable water treatment processes respond to these changes and maintain quality standards in the production of safe drinking water. The historical analysis of river Cauca turbidity and behavior of clarified and filtrated water allowed evaluating the effect of increase in raw water turbidity over water treatment conventional processes of Puerto Mallarino plant at Cali (Colombia). It was determined that the high turbidity of the water of river affected the treatment efficiency and also the quality of treated water; filtration was the most vulnerable stage to these high turbidity events. A high linear correlation between maximum turbidity and chemical products dose (coagulant and disinfectant) was identified.Publicación Acceso abierto Efecto del ozono en la remoción de materia orgánica disuelta de un efluente secundario(2013-11-07) Muñoz, J. F. (Juan Fernando); Orta, M. T. (Maria Teresa)This paper presents the results of treatment with ozone and subsequent fractionation of dissolved organic matter (DOM) from secondary effluent from Cerro de la Estrella wastewater treatment plant located in Mexico City. The ozonation was carried out with two concentrations of ozone in the gas phase (5 and 25 mg/L) and two contact times (10 and 20 min). Fractionation of DOM was made using the resins XAD-4 and XAD-8, in order to determine the amount of hydrophobic and hydrophilic organic matter present in the wastewater. The best results were achieved with a concentration of 25 mg/L and a contact time of 20 minutes, achieving removals of 85 % color, 63 % turbidity, 71 % chemical oxygen demand (COD) and 78 % of UV254. We also determined the composition of DOM of secondary effluent in terms of total organic carbon (TOC), finding that ozone causes the hydrophobic organic matter from the effluent studied to decrease from 46 % to 32 % and the hydrophilic organic matter to increase from 32 % to 42 %.Publicación Acceso abierto Efectos del mercurio sobre algunas plantas acuáticas tropicales(2014-05-08) Posada-Posada, M. I. (Martha Isabel); Arroyave-Maya, M. P. (Maria del Pilar)This paper describes the effects of mercury on some aquatic plants of the tropics and their habitats. Additionally, a protocol for toxicity tests in duckweed (Lemna minor) is recommended, and the results of preliminary tests with salts of mercury under laboratory conditions are given. It was found that mercury is in different toxicity and bioavailability forms depending on the factors that facilitate the solubilization of this element in the water. Many plants act as bioindicators because they withhold the metal selectively, while others are bioaccumulators since they tolerate and accumulate them in their structures producing biomagnification through the food web. The preliminary tests carried out in Lemna minor suggest that the appropriate concentrations for the toxicity tests are between 0,01 mg/L and 10,0 mg/L for Hg.Publicación Acceso abierto Estimación de las emisiones de contaminantes atmosféricos provenientes de fuentes móviles en el área urbana de Envigado, Colombia(2013-11-15) Londoño, J. (James); Correa, M. A. (Mauricio Andrés); Palacio, C. A. (Carlos Alberto)This research presents the results of estimates of air pollutants (CO, NOx, SO2, PM10 and VOC) from mobile sources in the urban area of the municipality of Envigado for 2010. We use information on vehicles registered in the municipality, capacity, vehicular distribution and activity for categories. The emissions were estimated by the factors in the IVE method with best fit to the mobility patterns, vehicular fleet characteristics and type of combustibles in the area under study. As a result, it was possible to estimate hourly and daily emissions of the pollutants studied, and with the help of a GIS system, were plotted. From the results, we found that the largest releases occurred on roads with higher vehicle traffic (Carrera 50 or Avenue Regional, Carrera 48 or Avenue Las Vegas, Carrera 43A or Avenue El Poblado and road parallel to the stream La Ayurá), where the largest contribution does carbon monoxide (CO) with 18,4 t d-1 (71,3 %), time of day which showed the highest emission of this pollutant is at 12:00 hours with 1,4 t h-1 (7,4 %) and the vehicle category that most contributes to environmental levels are Automobile with 8 t d-1 (32,7 %).Publicación Acceso abierto Estudio comparativo de la remoción de materia orgánica en humedales construidos de flujo horizontal subsuperficial usando tres especies de macrófitas(2013-11-21) Montoya, J. I. (Jorge Ignacio); Ceballos, L. (Leonardo); Casas, J. C. (Juan Carlos); Morató, J. (Jordi)Constructed wetlands appear at the present time like a promising technology in reducing the pollution by waste waters; this study investigated the organic matter removal with synthetic waste water, in terms of chemical oxygen demand (COD), biological oxygen demand (BOD5) and in situ measurements of pH, oxygen and temperatura every 15 days, during three months, in six horizontal subsurface-flow constructed wetland systems, in pilot scale, seeded with three different macrophytes: Canna limbata, Heliconia psittacorum and Phragmites sp; the average removals of COD were of 97,31 % and 95,94 % for Canna limbata; 94,49 % and 93,50 % for Heliconia psittacorum; 97,39 % and 97,13 % for Phragmites sp. In BOD they were of 100 % and 99,36 % for Canna limbata; 99,09 % and 97,49 % for Heliconia psittacorum; 100 % and 99,45 % for Phragmites sp. We conclude that there are significant differences in DQO removal between different plants (P < 0,05); in BOD5 removal significant differences between the different plants do not exist statistically (P < 0,05). This study demonstrates the option to reduce the polution from organic matter using constructed wetlands.Publicación Acceso abierto Evaluación ambiental para procesos que usan residuos de la industria de los biocombustibles como materias primas(2013-10-24) Valencia-Botero, M. J. (Mónica Julieth); Cardona, Carlos ArielThe industry of biofuels generates a lot of amounts of residues, which could be used to produce added-value products. In this work, a Life Cycle Assessment (LCA) methodological approach was used in the cases of glycerol and sugarcane bagasse during their productions and their uses as raw materials in four different processes. The aim of this work was to determine the environmental impact of those processes, by calculating the Greenhouse Gases (GHG) associated to their lifecycles. The results indicated that the GHG emissions from glycerol processes were larger than processes involving sugarcane bagasse. Nevertheless, the processes using glycerol as raw material could be considered as more efficient, since the GHG emissions associated with the glycerol use per mass unit were 75% lower than GHG emissions when the glycerol is used, with regard to sugarcane bagasse.