Artículos de revistas

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https://repositorio.uc.cl/handle/11534/1156

Esta colección incluye artículos de revistas de profesores de la Pontificia Universidad Católica de Chile, publicados en revistas nacionales y extranjeras.

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Now showing 1 - 20 of 1023

A 2D hydrodynamic-sedimentological model for gravel bed rivers. Part II, Case study: The Brenta River in Italy
(2013) Kaless, Gabriel; Moretto, Johnny; Delai, Fabio; Mao, Luca; Lenzi, Mario A.
A 2D depth average model has been used to simulate water and sediment flow in the Brenta River so as to interpret channel changes and to assess model predictive capabilities. The Brenta River is a gravel bed river located in Northern Italy. The study reach is 1400 long and has a mean slope of 0.0056. High resolution digital terrain models has been produced combining laser imaging detection and ranging data with colour bathymetry techniques. Extensive field sedimentological surveys have been also carried out for surface and subsurface material. The data were loaded in the model and the passage of a high intense flood (R.I. > 9 years) was simulated. The model was run under the hypothesis of a substantial equilibrium between sediment input and transport capacity. In this way, the model results were considered as a reference condition, and the potential trend of the reach was assessed. Low-frequency floods (R.I. » 1.5 years) are expected to produce negligible changes in the channel while high floods may focalize erosion on banks instead than on channel bed. Furthermore, the model predicts well the location of erosion and siltation areas and the results promote its application to other reaches of the Brenta River in order to assess their stability and medium-term evolution.
A 2D hydrodynamic-sedimentological model for gravel-bed rivers. Part I: Theory and validation
(2013) Kaless, Gabriel; Lenzi, Mario A.; Mao, Luca
This paper presents a novel 2D-depth average model especially developed for gravel-bed rivers, named Lican-Leufú (Lican=pebble and Leufu=river, in Mapuche’s language, the native inhabitants of Central Patagonia, Argentina). The model consists of three components: a hydrodynamic, a sedimentological, and a morphological model. The flow of water is described by the depth-averaged Reynolds equations for unsteady, free-surface, shallow water flows. It includes the standard k-e model for turbulence closure. Sediment transport can be divided in different size classes (sand-gravel mixture) and the equilibrium approach is used for Exner’s equation. The amour layer is also included in the structure of the model and the surface grain size distribution is also allowed to evolve. The model simulates bank slides that enable channel widening. Models predictions were tested against a flume experiment where a static armour layer was developed under conditions of sediment starvations and general good agreements were found: the model predicted adequately the sediment transport, grain size of transported material, final armour grain size distribution and bed elevation.
A Bayesian Approach to Establishing a Reference Particle Size Distribution in the Presence of Outliers
(2012) Page, Garritt L.; Vardeman, Stephen B.
The presence of observations or measurements that are unlike the majority is fairly common in studies conducted to establish particle size (or weight fraction) distributions. Therefore, there is a need to develop methods that are capable of producing estimates of particle size distributions that are not overly sensitive to the presence of a few observations that might be considered outliers. This article proposes a type of contamination mixture model that probabilistically allocates each observation to either a majority component or a contamination component. Observations that are allocated to a contamination component are down-weighted when estimating the particle size distribution (while the uncertainty of contamination classification is automatically accounted for in estimation). Computational methods are developed and the utility of the proposed methodology is demonstrated via a simulation study. The method is then applied to data produced from an inter-laboratory study conducted to establish a particle size distribution in cement.
A Binary Expansion Approach for the Water Pump Scheduling Problem in Large and High-Altitude Water Supply Systems
(2024) Cariaga, Denise; Lorca, Alvaro; Anjos, Miguel F.
The water pump scheduling problem is an optimisation model that determines which water pumps will be turned on or off at each time period over a given time horizon for a given water supply system. This problem has received considerable attention in mining and desalination due to the high power consumption of water pumps and desalination plants and the complicated dynamics of water flows and the power market. Motivated by this, in this paper we solve the optimal operation of a desalinated water supply system consisting of interconnected tanks and pumps that transport water to high-altitude reservoirs. The optimisation of this process encounters several difficulties arising from (i) the nonlinearities of the equations for the frictional losses along the pipes and pumps, which makes the problem a nonlinear mixed-integer model, and (ii) many possible combinations of pressure head and flow rates, which quickly leads to high computational costs. These limitations prevent the problem from being solved in a reasonable computational time in high-altitude water supply systems with more than six pumps and reservoirs, as in many networks worldwide. Therefore, in this work we develop new exact methods for the optimal pump scheduling problem that use a binary expansion approach to efficiently account for the existing nonlinearities by reducing the computational difficulties of the original problem while keeping an excellent representation of the physical phenomena involved. We also extensively tested the proposed approach in different network topologies and a case study for a real-world copper mine water network, and we conclude that the binary expansion approach significantly reduces the computational time for solving the problem with high precision, which can be very relevant for the practical daily operation of real-world water supply systems.
A Combined and Extended Procedure for Measuring the Soil Water Retention and Hydraulic Conductivity Curves
(2025) Contreras Torres, Cristina Pamela; Acevedo Godoy, Sara Ester; Avila Gorostiaga, Carlos Javier; Martinez, Sofia I.; Bonilla Melendez, Carlos Alberto
Soil-specific properties like water retention and hydraulic conductivity are largely used in soil and environmental modelling and are typically obtained after laboratory analyses. So far, no single method is available to measure the entire suction range for water retention or hydraulic conductivity. Common methods for describing the soil water retention curve (SWRC) include simplified evaporation, pressure plates, neutron spectroscopy, and dewpoint. Regarding hydraulic conductivity, the techniques vary for the saturated or unsaturated condition, using tension disks and transient evaporation methods. In the search for a procedure to describe the entire water retention and hydraulic conductivity curves, the objective of this study was to illustrate the combination and use of a series of laboratory methods in eight different semi-hierarchical combinations to cover the whole suction range (0 <=$$ \le $$ pF <=$$ \le $$ 7). The data obtained from each combination was used to fit the van Genuchten-Mualem equation and compared using the RMSE and Akaike statistics. The main results show that using a combination of many methods for the water retention and hydraulic conductivity curves did not necessarily improve the curve fitting. However, adding data points at near saturation (pF close to 0) or from the driest part of the curve (pF >=$$ \ge $$ 4) improved the estimates on both curves. Specifically, for the clay soil, the RMSE for the hydraulic conductivity curve decreased from 0.0372 to 0.0369 cm/d when measurements from near saturation were added. For the sandy loam 2 soil, the RMSE for the water retention curve decreased from 0.039 to 0038 when including data from the driest part of the curve. Among all the soil-water-related parameters tested in this study, the estimates for the water retention content at the permanent wilting point (theta 1500 kPa) showed the largest difference among all the combinations of methods, up to 52%. In contrast, the difference in the water content at field capacity (theta 33 kPa) estimates was only 3%. This study provides an evaluation and insights to identify the best combination of methods when measuring or parametrizing the soil water retention and hydraulic conductivity curves.
A comparative study of manhole hydraulics using stereoscopic PIV and different RANS models
(2018) Azim Beg, Md Nazmul; Carvalho, Rita F.; Tait, Simon; Brevis Vergara, Wernher; Rubinato, Matteo; Schellart, Alma; Leandro, Jorge
A composite indicator approach to assess the sustainability and resilience of wastewater management alternatives
(2020) Sun, Y.; Garrido Baserba, M.; Molinos Senante, María; Donikian, N. A.; Poch, M.; Rosso, D.; CEDEUS (Chile)
A comprehensive evaluation of pedotransfer functions for predicting soil water content in environmental modeling and ecosystem management
(2018) Contreras, Cristina P.; Bonilla Meléndez, Carlos Alberto; CEDEUS (Chile)
A decision support system for planning and scheduling bottling lines in a large winery
(2017) Mac Cawley, A.; Maturana Valderrama, Sergio; Pascual, R.
Planning and scheduling bottling lines in large wineries is an important process that greatly impacts production costs of large wineries, which have several of these lines, and the service level it provides to its clients. A ''good" plan needs to ensure that the wine is packaged and available on time to serve the demand, or else it can affect the service level given to the customer; it also should keep inventory low and efficiently use the bottling lines and labor. The many different aspects that have to be considered, such as the sequence of the products to be bottled, the constraints that have to be met due to production, sanitation, and labor requirements, the different types of setups, some of which are sequence dependent, and the large number of products that have to be scheduled on the different bottling lines, make it a very hard problem to solve without the help of a decision support system (DSS). We describe in this paper a DSS that was implemented for a large winery in the US that uses a mathematical model to help find a good plan that both minimizes production costs and maximizes the service level of their clients. The results obtained on test problems showed that the system could obtain cost reductions in the order of 15% to 30%. A visualization and intervention software was built into the system to support the planning process by allowing the planner an easy visualization of the production schedule through Gantt charts and also the possibility to intervene the solution using drag and drop. Key performance indicators are also presented to help analyze the solution from a cost, production parameter, demand, and capacity perspective. The system is able to provide good solutions in a reasonable amount of time, running on a standard personal computer.
A Dynamic, Multivariate Sustainability Measure for Robust Analysis of Water Management under Climate and Demand Uncertainty in an Arid Environment
(2015) Hunter Cure, Christian Kent; Gironás León, Jorge Alfredo; CEDEUS (Chile)
A First in Human Trial Implanting Microalgae Shows Safety of Photosynthetic Therapy for the Effective Treatment of Full Thickness Skin Wounds
(FRONTIERS MEDIA SA, 2021) Obaid, Miguel Luis; Camacho, Juan Pablo; Brenet, Marianne; Corrales Orovio, Rocio; Carvajal Diaz, Felipe Alonso; Martorell, Ximena; Werner, Consuelo; Simon, Valeska; Varas, Juan; Calderon, Wilfredo; Guzman, Christian Dani; Bono, Maria Rosa; San Martin, Sebastián; Eblen Zajjur, Antonio Alejandro; Egaña Erazo, José Tomás
Insufficient oxygen supply represents a relevant issue in several fields of human physiology and medicine. It has been suggested that the implantation of photosynthetic cells can provide oxygen to tissues in the absence of a vascular supply. This approach has been demonstrated to be successful in several in vitro and in vivo models; however, no data is available about their safety in human patients. Here, an early phase-1 clinical trial ( identifier: NCT03960164, ) is presented to evaluate the safety and feasibility of implanting photosynthetic scaffolds for dermal regeneration in eight patients with full-thickness skin wounds. Overall, this trial shows that the presence of the photosynthetic microalgae Chlamydomonas reinhardtii in the implanted scaffolds did not trigger any deleterious local or systemic immune responses in a 90 days follow-up, allowing full tissue regeneration in humans. The results presented here represent the first attempt to treat patients with photosynthetic cells, supporting the translation of photosynthetic therapies into clinics.
A First Omics Data Integration Approach in Hass Avocados to Evaluate Rootstock-Scion Interactions: From Aerial and Root Plant Growth to Fruit Development
(2024) Nunez-Lillo, Gerardo; Ponce, Excequel; Beyer, Clemens P.; Alvaro, Juan E.; Meneses, Claudio; Pedreschi, Romina
Grafting, the careful selection of rootstocks and scions, has played a crucial role maintaining Chilean avocado fruit quality standards in a scenario in which climate change and drought-related issues have considerably decreased avocado fruit production in the last fifteen years. The historical use of seedling rootstocks in Chile has experienced a recent shift towards clonal rootstocks, driven by the potential to produce more consistent and predictable crops. This research aims to compare Hass avocado plants grafted on Mexicola seedling and Dusa (R) clonal rootstocks in a soilless and protected system using (i) a differential expression analysis of root and leaf samples and (ii) a fruit transcriptomic and metabolomic integration analysis to improve our understanding of rootstock-scion interaction and its impact on avocado tree performance and fruit quality. The results demonstrated that no significant transcriptomic and metabolomic differences were identified at fruit level in the ready-to-eat (RTE) stage for Hass avocado fruit from both rootstocks. However, Hass avocados grafted on the clonal rootstock showed greater aerial growth and slightly increased fruit size than the seedling rootstock due to the enrichment of cell wall-remodeling genes as revealed in leaves and fruit at harvest stage.
A first-principles study on the adsorption properties of phosphorene oxide for pollutant removal from water
(2022) Cortes-Arriagada, Diego; Barria, Natacha; Ortega, Daniela E.; Araya-Duran, Ingrid; Camarada, Maria Belen
Phosphorene-based materials have emerged as useful platforms for new technological applications, including their potential implementation in the solid-phase extraction of pollutants. In this study, we implemented a first-principles study to characterize the interactions between water-soluble pollutants and phosphorene oxide (PhosO) at the microscopic level, providing useful mechanistic insights into the role of phosphorene oxidation in its adsorption/removal ability. Continuum/explicit solvent effects were considered to explain the solvent role, and the ALMO-EDA method characterizes the intermolecular forces. Our results show that PhosO significantly adsorbs pollutants on its surface by inner surface adsorption, even under aqueous environments, and provides remarkable adsorption stability for a wide family of water-soluble emerging contaminants (pharmaceuticals, endocrine disruptors, flame retardants, and industrial chemicals) with adsorption energies of 0.53 to 1.17 eV. The stabilizing energy in solution is driven by a balanced contribution of dispersion and electrostatic driving forces (up to 83% of the stabilizing energy), overcompensating all the destabilizing effects from the solvation process and Pauli repulsion. Furthermore, PhosO promotes low pollutant mobility from its surface under water molecules, which are not competitive factors in the adsorption process. In addition, simulations under dynamic conditions show that the electrostatic/dispersion governed mechanism remains stable at room conditions for real-life applications (300 K, 1 atm). Finally, a bandgap increase of 0.73 eV is noted in PhosO upon pollutant adsorption, giving a suitable framework for further sensing applications of contaminants by increasing the metallic character of PhosO. These results expand the understanding of the role of phosphorene oxidation for its use as a removal platform in water treatment technologies. (c) 2022 Elsevier B.V. All rights reserved.
A framework for hybrid model predictive control in mineral processing
(2015) Karelovic, Pablo; Putz, Eduardo; Cipriano, Aldo
A GIS-based urban and peri-urban landscape representation toolbox for hydrological distributed modeling
(2017) Sanzana Cuevas, Pedro Pablo; Gironás León, Jorge Alfredo; Brand, I.; Branger, F.; Rodríguez, F.; Vargas, X.; Hitschfeld, N.; Muñoz Pardo, José Francisco; Vicuña, Sebastián; Mejía, A.; Jankowski, S.; CEDEUS (Chile)
A hybrid representation approach for modelling complex dynamic bioprocesses
(2000) Thibault, J.; Acuna, G.; Perez Correa, Jose Ricardo; Jorquera, H.; Molin, P.; Agosin, E.
A hydrogeochemistry and isotopic approach for the assessment of surface water-groundwater dynamics in an arid basin : the Limari watershed, North-Central Chile
(2015) Oyarzun, Ricardo; Jofre, Elizabeth; Morales, Paulina; Maturana, Hugo; Oyarzun, Jorge; Kretschmer, Nicole; Aguirre, Evelyn; Gallardo, Patricio; Toro, Luis E.; Muñoz Pardo, José Francisco; Aravena, Ramón
A mechanism of male germ cell apoptosis induced by bisphenol-A and nonylphenol involving ADAM17 and p38 MAPK activation
(2014) Urriola Muñoz, Paulina Andrea; Lagos Cabré, Raúl Cristián.; Moreno Mauro, Ricardo D.
A method to estimate maximum and minimum air temperature using MODIS surface temperature and vegetation data : application to the Maipo Basin, Chile
(2015) Bustos, E.; Meza, Francisco Javier
A Mixed-Integer Programming Model for Gas Purchase and Transportation
(2005) Contesse Becker, Luis; Ferrer Ortiz, Juan Carlos; Maturana Valderrama, Sergio
The natural gas supply chain involves three main agents: producers, transportation companies, and local distribution companies (LDCs). We present a MIP model that is the basis for a decision support system developed for a Chilean LDC. This model takes into account many of the complexities of the purchasing and transportation contracts to help optimize daily purchase and transportation decisions in the absence of local storage facilities. The model was solved to optimality within a reasonable time. We show how the model handles several contractual issues and give some insights for the case when demand scenarios are used to deal with uncertainty.

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