Volumen 5 No. especial (2014) - IC: Congreso de Ingeniería Civil

Permanent URI for this collectionhttps://dspace-test.ucuenca.edu.ec/handle/123456789/21325

Browse

Now showing 1 - 19 of 19

Efecto del tiempo de residencia sobre la biooxidación de un mineral aurífero refractario
(Universidad de Cuenca, 2014) Jaramillo M., Katherine I.; Aguirre Ch., Paulina I.; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
Biooxidation is a pretreatment process for extraction of metals (gold) from sulfides ores using native microorganisms. Industrially, the biooxidation process is continuously applied since the volumetric productivity is high and the volume of the reactor can be kept low. In this type of system, the residence time is an indicator of conversion to be achieved; that is why, the objective of this study was to evaluate the effect of residence time on a continuous biooxidation system in order to get the best solubilization ore. Biooxidation tests were carried out in stirred tank reactors, thus experimenting with 2, 4, 6, 8 and 10 days; maintaining the next variables constant: speed of agitation (400rpm), air flow (3vvm), height of the rotor (3.5cm) , temperature (30°C), pH (1.8), particle size (-200 mesh) and pulp density (15% w/v). The process was monitored by measuring the concentration of Fe2+, total Fe, sulfates, plantonic protein, total protein, microbial counting, pH and Eh. The results showed that the best mineral solubilization was obtained with a residence time of 6 days, obtaining Qp Fe3+ of 6.64 g/Lday, Qp SO42- of 6.89 g/L day and gold recovery of 17%.
Rigidez y flexibilidad en el análisis de diafragmas flexibles
(Universidad de Cuenca, 2014) Soler de la Cruz, José Isaac; Pino Velázquez, Angel Julver; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
This paper presents the comparison between two classical general Structural Analysis Methods: the Stiffness (Displacements) and the Flexibility (Forces) method. Both methods determine the distribution of the lateral forces subjected to the action of said forces on a diaphragm, assuming flexibility.
Modelamiento de operación de embalses para el proyecto integral de riego en la cuenca del río Macul
(Universidad de Cuenca, 2014) Tinoco, Vicente; Willems, Patrick; Wyseure, Guido; Cisneros, Felipe; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
An irrigation project is planned in the Macul Basin Ecuador for developing the agriculture as the main income in the region. The proposed water system comprises three large reservoirs damming the rivers Macul and Maculillo. The river basin planning and operation was investigated by modelling alternative reservoir operation strategies aiming at a sustainable balance between irrigation and river ecology by integrated reservoir/river management. The model simulates the integrated water system for long term periods of data, covering also several historical extreme events. Results indicate that the planned irrigation volumes are higher than the available water for a sustainable irrigation. Two lines of action are suggested for reaching the target irrigation demands: one is to design a deficit irrigation schedule, and the second implies modification in the reservoir’s spillway height.
Predicción de caudales en la cabecera de la cuenca del Paute mediante el modelo DBM
(Universidad de Cuenca, 2014) Quichimbo, A.; Vázquez, R. F.; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
The Data-Based Mechanistic (DBM) model was used in conjunction with the Kalman filter (as a data assimilation technique), to predict the discharge from a sub-catchment located in the upper part of the Paute basin. The results showed that this conjunctive use of the DBM model and the Kalman filter produced better predictions of the discharge in the study site, as compared to the solely use of the DBM model; indeed, the use of the Kalman filter provided an estimate of the uncertainty associated to the use of the DBM model for forecasting purposes. These results not only motivate the future use of data mining techniques for discharge forecasting, but also encourage the use of the current tool for both, prediction as well as forecasting extreme events on Andean catchments.
Modelación física del flujo a través de las compuertas radiales de la derivadora Cañar
(Universidad de Cuenca, 2014) Tinoco, Vicente; Cisneros, Felipe; Pacheco, Esteban; Carrillo, Verónica; Calle, Edison; Domínguez, Juan; Garate, Johana; Solís, Katty; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
The Cañar River lower basin is a coastal flat area with a high hydro-economic potential, however this zone is vulnerable to flooding. The Ecuadorian Government invests in a flood control project. The project design alternatives need testing in a physical model for supporting the final design. The variables related to the flow through the radial gates of the diversion works are investigated in a physical model. A discharge curve was calibrated for the gate operation. In addition, the best gate location was determined, as well as the optimum still basin depth. Unusual osculation with negative flow directions were found for specific tests. This phenomenon has a scour effect. In order to solve this problem, changes in the geometry of the still basin entrance are recommended by adjusting it to the flow profile.
Indices de calidad del agua de fuentes superficiales y aspectos toxicológicos, evaluación del Río Burgay
(Universidad de Cuenca, 2014) Pauta Calle, Gladys Guillermina; Chang Gómez, José; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
The article presents an analysis of the water quality of the river Burgay, located in the province of Cañar, using the index of the Mexican Institute of Water Technology which is based on 18 conventional physical, chemical and microbiological parameters. Special emphasis has been given to the concentration of agricultural pesticides since the river water serves as supply for human settlements. The presence of pesticides affects the water quality and might restrict its use for human consumption. The study reveals that the conventional indexes depict a short-term sanitary risk of the river water due to the presence of pathogen organisms. The existence of pesticides however, when water is not treated, represents a long-term chemical risk because pesticides, even at non-detectable or low concentration level tend to accumulate in the body causing ultimately toxic effects on human’s health. The short-term sanitary risk is normally monitored by the water supply agency or institution appointed by this agency, via systematic, periodic and documented assays. Generally, neither the agency nor the appointed institution possesses the skills to measure the presence of pesticides, a task normally executed by another institution. The authors recommend that both monitoring institutions should coordinate their measurements, as a mechanism to derive a complete picture of the water quality as to minimize the risk and ensure the health of the consumers.
Transporte de fondo potencial mediante estudio en modelo físico de lecho móvil
(Universidad de Cuenca, 2014) Pacheco T., Esteban A.; Carrillo S., Verónica M.; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
Potential bed-load transport rates are determined by an experimental study in a moving-bed physical model. This study was conducted for the HidroSanBartolo hydroelectric project located in Negro river South of Ecuador. Prospective bed-load rates were established with five theoretical equations for the fluvial hydrology conditions of interest. Additionally, according to the governing laws of the morphological equilibrium of a natural channel, the river response to erosion-accretion processes is evaluated through a control point upstream. Also, based on the bed slope, the theoretical rates are calibrated. Considering the control morphodynamic mechanisms, the Nielsen simplified method was established as the recommended scheme to calculate the transport rates, to calibrate the model, and to analyze the scenarios for the river. The final rates obtained represent the 85% percent of the values calculated with this formulation with values of 662 kg/s for the channel forming flow of 50 m3/s and 914 kg/s for the humid season flow of 75 m3/s.
Identificación de infraestructuras viales y educativas de la cuenca del Paute en riesgo mediante técnicas de análisis espacial
(Universidad de Cuenca, 2014) Villavicencio, David; Vásquez, Rocío; Muñoz, Daniel; Acosta, Enrique; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
Among the socio-economic development plans of a country, the civil works such as roads and education centers are a priority. Depending on geographic location, different types of natural phenomena can endanger these human elements. Therefore, the aim of this work is to identify education centers and roads exposed to two types of risk: flash floods and slope movements. To reach this goal, techniques of vector spatial analysis in a Geographic Information System have been applied. The results show that 14.6% of education centers are at risk of flooding, and 6.7% at risk of slope movements. Regarding the roads, the study found that 42.9 kilometers of track are at risk of flooding, and 19.9 kilometers at risk of slope movements.
El efecto P-delta y su influencia sobre la ductilidad de las estructuras metálicas del Ecuador
(Universidad de Cuenca, 2014) Vielma P., Juan C.; Cando L., Manuel A.; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
Current earthquake-resistant procedures prescribe generic values for the response reduction factors, regardless of the configurational and geometric characteristics of the designed buildings. It is well know that those response reduction factors values reflect the expected behaviour of the structures when they are under strong ground motions, being this seismic behaviour usually evaluated through ductility and over strength. In this work, calculated values of the ductility of special moment- resisting steel frames with different span lengths and designed according the Ecuadorian Construction Code, are presented. Results show that the ductility of the buildings is strongly influenced by the spans length and they would reach inadequate values if the second-order effect P − Δ occurs
Evaluación de la distribución del caudal específico en aliviaderos escalonados sin cajeros laterales
(Universidad de Cuenca, 2014) Estrella, Soledad; Sánchez-Juny, Martí; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
Traditionally the construction of stepped spillways in roller compacted concrete dams (RCC) is characterized by the presence of sidewalls that imposes a constant width along the spillway and guides the flow from the crest to the toe. These sidewalls imply significant time and cost of execution that could be considerably reduced. In the specialized literature there is a comprehensive description of the hydraulic behavior of stepped chutes with sidewalls and besides that recently few examples of stepped spillways designed without sidewalls have been found no formal investigation defines the hydraulic behavior in this condition. In this context arises the ALIVESCA with the objective of characterizing the hydraulic behavior of stepped spillways without sidewalls in RCC dams by physical modeling. The model located in Flumen Institute's laboratories (UPC), operates under the Froude similarity. It was constructed representing a 75 m dam height, 1.20 m step height, 0.8 slope and 45 m dam width (scale 1:15). In this article, the decrease of the specific discharge along and across the chute due to the flow lateral expansion is defined. The variables that determine such decrease are: the specific discharge at the entrance and the position (height) considered. Thus, an adjustment is proposed to predict the flow distribution in terms of these variables by mass conservation defined using flow gauging and image digital analysis.
Tratamiento químico y biológico de efluentes mineros cianurados a escala laboratorio
(Universidad de Cuenca, 2014) Jumbo Pacheco, Pablo Xavier; Nieto Monteros, Diego Alejandro; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
Cyanide is a chemical compound used per excellence for gold leaching in the mining industry. However, it is highly toxic for the environment and its organisms. This work focused on determining the optimum conditions for the degradation of CN- using chemical compounds and a microbial consortium. Chemical and biological assays were performed separately using samples of mining effluents at different cyanide concentrations (280 and 10 mg/L CN-). For chemical degradation, three different oxidizing compounds were used: sodium hypochlorite, Caro’s acid and hydrogen peroxide at different concentrations, pH (10-11), and degradation times (4.71 and 20.75 h.). For the biodegradation assays, a microbial consortium was cultivated in flasks containing the cyanide effluent, liquid medium, pH (11), agitation (200 rpm) and temperature (20±5°C). Free cyanide concentration, pH and the biomass concentration were measured. Chemical treatment results showed that the best oxidizing compound was hydrogen peroxide (8:1 g H2O2 / g CN-) and pH (10), thus obtaining a 92.73% removal of free cyanide in 45 minutes (280 mg/L CN-) and 91.01% removal in 25 minutes (10 mg/L CN-). While in biodegradation the removal was 73.68% (280 mg/L CN-) in 384 h and 78.57% (10 mg/L CN-) in 240 h.
Análisis no lineal del pandeo de columnas esbeltas para cargas estáticas
(Universidad de Cuenca, 2014) Moscoso Fernández Salvador, Jorge Fernando; Alvarez Ruilova, Juan; Argudo Sánchez, Geovanny; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
The design of reinforced concrete structural elements has improved over the years due to better knowledge of the behavior of its comprising materials. Columns as structural elements are very important in the structure life span. This paper develops a method for testing and analyzing nonlinear slender rectangular reinforced concrete columns and concrete filled steel columns, whose aim is to calculate the geometric and mechanical guideline of a column to determine the maximum moment which can withstand an axial load due to either depletion or instability. The method comprises an iterative process in which the neutral fiber depth and the radius of curvature. Graphics solutions (Guideline geometric and mechanical) that indicate the status of the last column were obtained. The method is versatile as it can be used to analyze columns consisting of different types of materials incorporating only stress-strain diagram; also the method is optimal as to check if a certain combination of column load resists, is not necessary to construct the interaction diagram
Modelización hidrogeológica de una cuenca cárstica
(Universidad de Cuenca, 2014) Montalvo, C. I.; Abril, O. A.; Vázquez, R. F.; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
The surface and groundwater hydrology of a karst catchment located in Belgium was modelled using the distributed physically based code MIKE SHE. The calibration and validation processes were carried out through a common split-sample (i.e., temporal) analysis as well as through a more specialised multi-site (i.e., spatial) analysis. Further, a sensitivity analysis was run varying the calibrated parameters beyond their calibration values, which showed that the most sensitive parameter for the simulation of both surface as well groundwater flows, is the horizontal hydraulic conductivity of the karst layer, in congruence to what has been observed in situ. Both, the surface and groundwater model predictions can be regarded as being satisfactory,
Evaluación de modelos hidrodinámicos para representar flujos en cauces naturales
(Universidad de Cuenca, 2014) Ochoa García, Santiago Aurelio; Reyna, Teresa; Reyna, Santiago; García, Marcelo; Patalano, Antoine; Labaque, María; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
The free flow occurs when the liquid flows by gravity and only partially confined by a solid circle. In the prediction of the flow variables for different conditions is of great importance to develop hydrodynamic models and numerical simulations with adequate precision to allow proper planning of works. We have studied the use of analytical models in solving phenomena fluid mechanics, which are based on the laws of conservation of mass, momentum and energy. Depending on the degree of simplification that can be reached while maintaining the level of accuracy and verify what good behavior modeled on the nature, there are one-dimensional, two-dimensional and three-dimensional hydrodynamic schemes. A confluence is a complex adaptive convergence since complicated flow parameters produce fluids movement. In this paper the formulation, solution methods and methodologies for developing overall physical and mathematical models for free surface flows is presented. For this study the confluence of the La Cañada stream and Suquía River both of the City of Córdoba.
Diseño y construcción de una máquina semiautomática para la fabricación de bloques
(Universidad de Cuenca, 2014) Mise, Diego; Universidad de Cuenca, Dirección de Investigación de la Universidad de Cuenca; DIUC
This paper presents the design of a semi-automatic concrete block machine, aiming the simplification of the manual fabrication. The manuscript first describes the fabrication process in detail, followed by the technical specifications the machine should have, alternative design approaches, and the selection of the best design. A model type was created as design guide for machine elements and the selection of standard elements. The machine design is supported by engineering calculations, and the analysis of stresses and deformations pursued by the finite element method in the Inventor 2013. Than shop drawings for the construction of machine were made, and finally, the machine was constructed and tested.
Prototipos virtuales para la industrialización abierta de la construcción: un caso de estudio
(Universidad de Cuenca, 2014) Samaniego, Pedro; Samaniego, Esteban; Samaniego, Augusto; Astudillo, Francisco; Díaz, Michelle; Cordero, Dolores; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
Industrialization has not yet had a notorious impact in the construction sector. Inefficiencies associated with the lack of reliable tools to simulate the building process are pervasive. Here, we adopt the so-called open-industrialization paradigm and use virtual prototyping to study a specific construction system. We explore the possibilities of this system and show the capabilities of virtual building modeling to detect inconsistencies when prefabricated elements are integrated.
Application of the grid convergence index to a laminar axisymmetric sudden expansion flow
(Universidad de Cuenca, 2014) Carrillo Serrano, Verónica Margarita; Petrie, John; Pacheco Tobar, Esteban Alonso
The use of numerical models to represent natural processes is increasingly common. The development of advanced numerical tools allows a more physically-based representation of complex flow phenomena. While more advanced systems can be solved, the uncertainty of the accuracy of the solutions obtained remains. The mere comparison between experiments and simulations is not enough proof of strength of the results. The Grid Convergence Index (GCI) methodology has been proposed with the aim to provide a mechanism to calculate and report discretization errors estimates in computational fluid dynamics (CFD) simulations. It permits the quantification of the uncertainty present in grid convergence. This method uses a grid convergence error estimator that is obtained by applying the generalized Richardson Extrapolation theory. The process is applied to an axisymmetric sudden expansion laminar flow case. Experimental results are used to verify the numerical simulation and GCI outcome. As a result of the application of this method the order of accuracy of the numerical scheme was verified. Additionally, comparing the numerical results with the experimental values, a maximum error of 6% was obtained. Finally, considering the two finest meshes, it can be concluded that the asymptotic range has been reached and that a finer Mesh won’t improve the accuracy of the solution when considering the increased numerical cost.
Imágenes TRMM para identificar patrones de precipitación e índices ENSO en Ecuador
(Universidad de Cuenca, 2014) Campozano Parra, Lenin Vladimir; Ballari, Daniela Elisabet; Célleri Alvear, Rolando Enrique; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca
Understanding spatio-temporal precipitation patterns and how they are related to ENSO are important to predict the spatial impact of ENSO events and develop early warning systems. While ENSO has been previously studied in Ecuador using rain gauge data, its impact on the spatial rainfall pattern is largely unknown. Thus, the purpose of this study was to use the Tropical Rainfall Measuring Mission satellite imagery (TRMM) to identify spatio-temporal patterns of precipitation from January to April, the season more affected by ENSO in Ecuador, and their relation with ENSO indexes. Principal component analysis was applied over the 16-year TRMM imagery, and score time series were correlated with the tropical Pacific surface sea temperature (tP SST) of Niño 1+2 region as well as with the Trans Niño Index (TNI). Results suggest that TNI and Niño 1+2 indicators are both needed to estimate the impact of tP SST on the precipitation during JA season. Strong positive anomalies on Niño 1+2 are positively correlated with higher precipitation in coastal plain of Ecuador and below average precipitation in the Amazon region. High values of TNI are directly related to an enhancement of precipitation all over the country.
Tendencias en infraestructuras de datos espaciales en el contexto latinoamericano
(Universidad de Cuenca, 2014) Ballari, Daniela Elisabet; Vilches, Luis; Randolf Perez, Diego; Pacheco, Diego; Fernández, Virginia; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca
Because of technological trends such as mobile devices, sensors and web2.0, Spatial Data Infrastructures (SDI) are converging to mobile systems in real-time and with active citizen participation. While these trends have been already analyzed and integrated as part of the SDI in Europe and North America, in the Latin American context, they have not been deeply investigated. Therefore, in order to contribute to its progress in Latin America, this article presents the state of the art of SDI’s trends in Latin America from a literature review, complemented with a regional survey. The results show that despite major initiatives implementing SDI’s trends; their progress in Latin America is still incipient, being still in what is call the second stage of evolution.

Browse

Browsing Volumen 5 No. especial (2014) - IC: Congreso de Ingeniería Civil by Issue Date