Papers by Fernando Betancourt
Minerals
The operation of a froth flotation column can be described by a nonlinear convection–diffusion pa... more The operation of a froth flotation column can be described by a nonlinear convection–diffusion partial differential equation that incorporates the solids–flux and drift–flux theories as well as a model of foam drainage. The resulting model predicts the bubble and (gangue) particle volume fractions as functions of height and time. The steady-state (time-independent) version of the model defines so-called operating charts that map conditions on the gas and pulp feed rates that allow for operation with a stationary froth layer. Operating charts for a suitably adapted version of the model are compared with experimental results obtained with a laboratory flotation column. Experiments were conducted with a two-phase liquid–bubble flow. The results indicate good agreement between the predicted and measured conditions for steady states. Numerical simulations for transient operation, in part for the addition of solid particles, are presented.
Minerals
The discrete element method (DEM) has been widely employed to model processes in different indust... more The discrete element method (DEM) has been widely employed to model processes in different industries, such as mining, agriculture, pharmaceuticals, and food. One of the main lines of research, and in which different authors propose several approaches, is the calibration of parameters. Bulk calibration (BCA) is a common approach used that does not necessarily represent the individual behavior of each particle. On the other hand, direct measurement (DMA) is another approach employed in some cases. This work presents a comparison between calibration of DEM model parameters with non-cohesive spherical and polyhedral particles using a combination of direct measurement and bulk calibration. BCA is employed to calibrate friction parameters and DMA to characterize shape of the particles and coefficient of restitution of the contact between particles. Experimental data from Draw Down Tests are used to calibrate the friction parameters. Numerical optimization of the parameters is conducted b...
593 Digital Publisher CEIT
El mundo entero enfrenta una situación inusitada a causa de la aparición del covid – 19 que ha pu... more El mundo entero enfrenta una situación inusitada a causa de la aparición del covid – 19 que ha puesto en riesgo no solamente la salud sino además la economía de la humanidad. Ecuador es uno de los países más golpeados por los efectos devastadores de este nuevo virus. Uno de los sectores que se ha mantenido activo desde las medidas de confinamiento para controlar las cifras de contagio, es el agrícola, no obstante, las pequeñas y medianas empresas dedicadas al suministro de productos agrícolas también sufren los efectos negativos de esta pandemia, esto motivó que para el desarrollo del presente trabajo se considere el estudio de las pymes agrícolas del cantón Arenillas, perteneciente a la provincia de El Oro, donde las actividades del agro son su principal fuente de ingresos económicos. El objetivo principal de este estudio estuvo orientado a replantear la gestión empresarial ante la crisis del covid-19 y el escenario futuro en las pymes agrícolas del cantón Arenillas. Para cumplir c...
Minerals
Comminution by gyratory crusher is the first stage in the size reduction operation in mineral pro... more Comminution by gyratory crusher is the first stage in the size reduction operation in mineral processing. In the copper industry, these machines are widely utilized, and their reliability has become a relevant aspect. To optimize the design and to improve the availability of gyratory crushers, it is necessary to calculate their power and torque accurately. The discrete element method (DEM) has been commonly used in several mining applications and is a powerful tool to predict the necessary power required in the operation of mining machines. In this paper, a DEM model was applied to a copper mining gyratory crusher to perform a comprehensive analysis of the loads in the mantle, the crushing torque, and crushing power. A novel polar representation of the radial forces is proposed that may help designers, engineers, and operators to recognize the distribution of force loads on the mantle in an easier and intuitive way. Simulations with different operational conditions are presented and...
Mining, Metallurgy & Exploration
El artículo busca estudiar las posibilidades de reconceptualizar la noción moderna de tiempo. Se ... more El artículo busca estudiar las posibilidades de reconceptualizar la noción moderna de tiempo. Se exploran las implicaciones que para esta tarea suponen el cambio de enfoque y una nueva modalidad de interrogación. En el primer caso, se introduce la dimensión del observador como premisa básica. En el segundo, se interroga sobre cómo es posible el tiempo. Ambas cuestiones permiten reformular el concepto entendiéndolo como un esquema de observación. Se analizan, además, las formas derivadas tanto de horizontes como de estructuras temporales y de historicidad.
Historia y Grafía, Universidad Iberoamericana, México, v. 23, n. 46, enero-junio de 2016., Jan 6, 2016
espanolResumen: El objetivo del presente texto es explorar la manera en que Freud planteo el prob... more espanolResumen: El objetivo del presente texto es explorar la manera en que Freud planteo el problema de la escritura en relacion con las descripciones metapsicologicas del aparato psiquico. En este sentido, ?cual es la importancia teorica de la metafora en la descripcion topica del aparato animico? ?Es posible pensar en una ampliacion semantica de la funcion escrituristica a partir de las propias deliberaciones freudianas? ?Como se relacionan metafora y escritura en el saber psicoanalitico? Estas son las preguntas centrales que buscan ser desarrolladas, aunque se debe explicitar que el marco general de referencia que da pie a su tratamiento no es otro que la teoria de sistemas contemporanea y las implicaciones epistemologicas que se desprenden de sus enfoques. Asi, se busca calibrar la pertinencia de una perspectiva que ve al aparato psiquico como un sistema operativo de alta complejidad, autopoietico por el hecho de que sus operaciones enlazadas se reproducen a partir de los mismos elementos operativos, ademas de que exhibe cualidades autoorganizativas gracias a la diferenciacion funcional. EnglishAbstract: This text aims to explore the way in which Freud problematizes writing in relation with meta-psychological descriptions of the psychic apparatus. Which is the theoretical importance of the metaphor in the animic apparatus’ place description? Is it possible to think on a wider semantic around the function of writing, stemming from Freud’s analysis? How does metaphor and writing relate in psychoanalysis? These central questions ought to be developed. However, it must be cleared that the general framework upon which this work is made, is no other than the contemporary theory of systems and the epistemological gatherings that came from its focus. Therefore, equilibrium between a particular view is heeded: this sees the psychic apparatus as a highly complex operative system which is autopoietic by the fact that its crossed operations are reproduced from the same operative elements; it also shows self-governed qualities based on a functional difference.
Salud Publica De Mexico, 2014
One-dimensional models to simulate secondary settling tanks (SST) with cylindrical geometry are w... more One-dimensional models to simulate secondary settling tanks (SST) with cylindrical geometry are widely used in wastewater treatment. One of these models is the Bürger-Diehl model developed in [3], the respective extention to the varying crosssectional area case was recently made in [1]. For the modelling, simulation and control of SST according to this model it is necessary to know the hindered-settling velocity function, which is considered a constitutive functions of the model. The traditional way to get this function is to measure the velocity of the declining sludge blanket in a vessel with constant cross-sectional area through experiments obtained from laboratory batch tests, however this method gives only one point on the flux curve. A newly developed method in [2] shows that in a vessel with varying cross-sectional area a large part of the flux function can be estimated from a single batch test, where the largest interval can be obtained with conical vessels. The identificati...
En la concurrencia del derecho real de propiedad con el ususfructus, el proprietarius dispone, po... more En la concurrencia del derecho real de propiedad con el ususfructus, el proprietarius dispone, por los danos que pueda causar el usufructuario, de los siguientes recursos : como acciones penales, de la a) actto legis Aquiliae, b) actio furti, c) actio servi corrupti, d) actio iniuriarum y e) del interdicto quod vi aut clam. Por otro ]ado, la cautio usufructuaria, que el pretor exige al usufructuario para garantizar el use y disfrute de la cosa salva rerum substantia, y la restituci6n oportuna de la mtsma. Nuestro anilisis versara sobre los danos causados por las o m i s i o n e s del usufructuario, es decir, el caso de qui ,agrum non proscindit, qui vites non subserit . item aquarum ductus conrumpi patitur (D.7,1,13,2), omisiones que no preveia la lex Aquilia.
Minerals, 2020
Froth flotation is a process in which hydrophobic particles attach to bubbles forming particle–bu... more Froth flotation is a process in which hydrophobic particles attach to bubbles forming particle–bubble aggregates, which are transported to the top section of the cell where they overflow to form the concentrate. Particles also reach the concentrate by entrainment, which is a non-selective process that leads to low concentrate grades. The objective of this work was to study and compare the degree of entrainment measured using three methods, in fresh and seawater, and using methyl isobutyl carbinol (MIBC) and DF-250 as frothers. The experimental results indicated that the degree of entrainment decreased in seawater. Besides, water recovery was lower in the experiments with seawater regardless of the frother that was used in the experiments, which correlated with the observed low degrees of entrainment. It is proposed that the reduction of entrainment and water recovery in seawater can be explained by a reduction of air recovery and/or more bubble coalescence in the froth. It is also p...
Annales Universitatis Mariae Curie-Sklodowska, sectio B – Geographia, Geologia, Mineralogia et Petrographia, 2020
W artykule opisano obecną sytuację i udział odnawialnych źródeł energii w systemie elektroenerget... more W artykule opisano obecną sytuację i udział odnawialnych źródeł energii w systemie elektroenergetycznym jednego z departamentów Kolumbii – Valle del Cauca. W ramach badania dokonano interpretacji ram instytucjonalnych dotyczących energii odnawialnej w Kolumbii oraz ogólnej analizy światowego i kolumbijskiego systemu elektroenergetycznego. Kolejna kwestia to udział odnawialnych źródeł energii w wytwarzaniu energii elektrycznej w Valle del Cauca, głównie w zakresie produkcji i infrastruktury energii hydroelektrycznej, bioenergii i energii fotowoltaicznej. W dalszej części autorzy skoncentrowali się na kwestii potencjału elektrycznego energii odnawialnej w omawianym regionie. Ponadto przedstawiono szereg dyskusji na temat tego, jak omawiany departament skorzystał z ram instytucjonalnych dotyczących wykorzystania energii odnawialnej.
Minerals Engineering, 2020
Ultraflocculation can be defined as: flocculation performed in a highly non-uniform hydrodynamic ... more Ultraflocculation can be defined as: flocculation performed in a highly non-uniform hydrodynamic field (> ε 1 [J/kg•s], G > 10 3 [ − s 1 ]) in a short period of time (< t 10 [s]), which is used mainly to aggregate fine particles in dispersed, and diluted systems. In this study, four hydraulic ultra-flocculation reactors were tested, UF1, UF2, UF3 and UF4 with tangential inlets/outlets and a cylindrical body, the inside of which varies by reactor. Model flocculated fine quartz slurries were employed as material. Based on a comparison of the three flocculation process indicatorsinitial settling velocity, supernatant turbidity, and sludge volumein general the reactors present better performance than that in the base case. There was an average improvement in settling velocity of 300[%], turbidity remains below 100 [NTU], and sludge volume values indicated a higher possibility of water recirculation. Additionally, it was observed that the ultra-flocculation process could be used in relatively concentrated suspensions (> − φ 10 2) with treatment times below to 5 [s].
Chemical Engineering Science, 2019
The coalescence and sedimentation of drops in liquid/liquid systems is a very common and importan... more The coalescence and sedimentation of drops in liquid/liquid systems is a very common and important stage in many industries (crude oil production, metallurgy extraction, wastewater treatment and pharmaceutical processes). Several models have been proposed on this topic. Population balance equations (PBE) provide a suitable a framework for dealing with drop breakage and coalescence. In addition, modeling of the solid particle sedimentation process based on Kynch's theory has been successfully used and validated in mineral processing and wastewater treatment. In this work, we present a model that merges the coalescence process with hindered polydisperse sedimentation. The PBE model is projected onto a partial differential equation (PDE) system by discretizing the droplet volume. Because there is loss of mass in the system when the daughter droplets are greater than the larger species considered for the numerical solution, two terms that produce the conservation of the mass or total volume of the dispersed phase are incorporated into the PDE system. The resulting PDE system is split into two systems: homogeneous PDEs and ordinary differential equations (ODEs). The homogeneous PDEs and the ODEs are discretized using a first-order central differencing scheme and the second-order, two-stage Runge-Kutta method, respectively. The model predicts the vertical variation of the composition of the dispersed phase layer that forms at the top or bottom of the gravity settler. The proposed model was calibrated and validated through an experiment with an oil and water system. In particular, simulations illustrate the effects of: the continuity of the dispersion (oil-in-water and water-in-oil) and the standard deviation of the initial droplet volumes on phase separation quality, as well as the influence of the coalescence frequency on the average droplet volume.
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Papers by Fernando Betancourt