La Serena, Chile
La Serena, Chile

The University of La Serena ) is a university in Chile. It is part of the Chilean Traditional Universities. It is located 350 miles north of Santiago. The university has five campuses: three in La Serena, one in Coquimbo, and one in Ovalle. It was founded in 1981, and approximately 8,000 students are currently enrolled there. Wikipedia.


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Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: ENV.2007.1.1.5.2. | Award Amount: 8.54M | Year: 2008

As the evidence for human induced climate change becomes clearer, so too does the realization that its effects will have impacts on natural environment and socio-economic systems. Some regions are more vulnerable than others, both to physical changes and to the consequences for ways of life. The proposal will assess the impacts of a changing climate on the quantity and quality of water in mountain regions. Modeling techniques will be used to project the influence of climatic change on the major determinants of river discharge at various time and space scales. Regional climate models will provide the essential information on shifting precipitation and temperature patterns, and snow, ice, and biosphere models will feed into hydrological models in order to assess the changes in seasonality, amount, and incidence of extreme events in various catchment areas. Environmental and socio-economic responses to changes in hydrological regimes will be analyzed in terms of hazards, aquatic ecosystems, hydropower, tourism, agriculture, and the health implications of changing water quality. Attention will also be devoted to the interactions between land use/land cover changes, and changing or conflicting water resource demands. Adaptation and policy options will be elaborated on the basis of the model results. Specific environmental conditions of mountain regions will be particularly affected by rapidly rising temperatures, prolonged droughts and extreme precipitation. The methodological developments gained from a European mountain focus will be used to address water issues in regions whose economic conditions and political structures may compromise capacities to respond and adapt, such as the Andes and Central Asia where complex problems resulting from asymmetric power relations and less robust institutions arise. Methodologies developed to study European mountains and their institutional frameworks will identify vulnerabilities and be used to evaluate a range of policy options.


Roman-Lopes A.,University of La Serena
Monthly Notices of the Royal Astronomical Society | Year: 2013

In this paper, we report on the discovery of an O2 If*/WN6 star probably still partiallyembedded in its parental cocoon in the starburst cluster NGC 3603. From the observed size ofthe associated compact HII region, it has been possible to derive a probable dynamic age ofno more than 600 000 yr. Using the computed visual extinction value AV ~ 6.0 ± 0.2 mag, anabsolute visual magnitude MV = -5.7 mag has been obtained. For the assumed heliocentricdistance of 7.6 kpc, this results in a bolometric luminosity of 8 × 105 L. Also, from the Vmagnitude and the V - I colour of the new star, and from previous models for the massive starpopulation of NGC 3603, we estimate the mass of the binary (O2 If*/WN6 + O3 If) and thesingle star (O2 If*/WN6). For the binary, we find that the initial masses of each componentpossibly exceed 80 and 40 M·, respectively, while for the single star the initial mass of MTT58 is possibly in excess of 100 M·. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.


Solid vapor pressures (PS) of pure compounds have been estimated at several temperatures using a hybrid model that includes an artificial neural network with particle swarm optimization and a group contribution method. A total of 700 data points of solid vapor pressure versus temperature, corresponding to 70 substances, have been used to train the neural network developed using Matlab. The following properties were considered as input parameters: 36 structural groups, molecular mass, dipole moment, temperature and pressure in the triple point (upper limit of the sublimation curve), and the limiting value PS → 0 as T → 0 (lower limit of the sublimation curve). Then, the solid vapor pressures of 28 other solids (280 data points) have been predicted and results compared to experimental data from the literature. The study shows that the proposed method represents an excellent alternative for the prediction of solid vapor pressures from the knowledge of some other available properties and from the structure of the molecule. © 2009 Elsevier B.V. All rights reserved.


Roman-Lopes A.,University of La Serena
Monthly Notices of the Royal Astronomical Society: Letters | Year: 2012

In this work we report the discovery of a new Galactic O2If*/WN6 star, a rare member of the extremely massive hydrogen core-burning group of stars that, because of their high intrinsic luminosity (close to the Eddington limit), possess an emission-line spectrum at the beginning of their main-sequence evolution, mimicking the spectral appearance of classical Wolf-Rayet (WR) stars. The new star is named WR 42e and is found in isolation at 2.7arcmin (~6 pc) from the core of the starburst cluster NGC 3603. From the computed E(B - V) colour excess and observed visual magnitude it is possible to estimate its absolute visual magnitude as M V =-6.3 mag, which is a value similar to those obtained by other researchers for stars of similar spectral type both in the Galaxy and in the Large Magellanic Cloud. Considering the derived absolute visual magnitude, we compute a bolometric stellar luminosity of about 3.2 × 10 6 L⊙ Finally, we estimate the mass of the new O2If*/WN6 star by comparing its MTSY.-1.circledot observed magnitudes and colours with those of other probable NGC 3603 cluster members, finding that the initial mass of WR 42e possibly exceeds 100M⊙. © 2012 The Author. Monthly Notices of the Royal Astronomical Society © 2012 RAS.


Lazzus J.A.,University of La Serena
Journal of Molecular Liquids | Year: 2012

A new model based on group contribution method to predict the decomposition temperature of several ionic liquids is developed. Experimental data of 120 ionic liquids were used to obtain the contributions for the cation-anion groups in a correlation set. The optimum parameters of the method were obtained using a genetic algorithm-based on multivariate linear regression. Then, the melting temperatures of another 78 ionic liquids were predicted, and the results were compared with experimental data available in the literature. The results show that the group contribution method represents an excellent alternative for the estimation of the decomposition point of diverse ionic liquids from the knowledge of their molecular structure with a correlation coefficient of 0.9359 and average deviation of 4%. © 2012 Elsevier B.V. All rights reserved.


Based on biologically inspired algorithms, a thermodynamic model to describe the vapor-liquid equilibrium of binary complex mixtures containing supercritical fluids and ionic liquids, is presented. The Peng-Robinson equation of state with theWong-Sandler mixing rules are used to evaluate the fugacity coefficient on the systems. Then, a hybrid particle swarm-ant colony optimization was used to minimize the difference between calculated and experimental bubble pressure, and calculate the binary interaction parameters for the excess Gibbs free energy of all systems used. Simulations are carried out in nine systems with imidazolium-based ionic liquids. The results show that the bubble pressures were correlated with low deviations between experimental and calculated values. These deviations show that the proposed hybrid algorithm is the preferablemethod to describe the phase equilibrium of these complex mixtures, and can be used for other similar systems. © 2013 Global-Science Press.


Lazzus J.A.,University of La Serena
Thermochimica Acta | Year: 2012

A simple group contribution method to predict the glass transition temperature of several ionic liquids is present. Experimental data of 150 ionic liquids were taken from the literature and used to obtain the contributions for the cation-anion groups in a correlation set. The optimum parameters of the method were obtained using a genetic algorithm-based on multivariate linear regression. The capabilities of the designed method were tested in the prediction of the glass point of another 100 ionic liquids not used in the correlation step. The results show that the group contribution method represents an excellent alternative for the estimation of the glass transition temperature of diverse ionic liquids from the knowledge of their molecular structure with an average deviation of 5% and a correlation coefficient of 0.91. © 2011 Elsevier B.V. All rights reserved.


Lazzus J.A.,University of La Serena
Fluid Phase Equilibria | Year: 2012

The melting points of several families of ionic liquids were predicted with a simple group contribution method. A set of 200 ionic liquids was used to obtain the contributions for anion and cation groups. The optimum parameters of the method were obtained using a genetic algorithm-based on multivariate linear regression. Then, the melting temperatures of another 200 ionic liquids were predicted, and the results were compared with experimental data available in the literature. The study shows that the proposed group contribution method represents an excellent alternative for the estimation of the melting point of diverse ionic liquids from the knowledge of their molecular structure, with an average deviation of 7%. © 2011 Elsevier B.V.


Lazzus J.A.,University of La Serena
Computers and Mathematics with Applications | Year: 2010

A method to model the vaporliquid phase based on a particle swarm algorithm is developed in this study. Two activity coefficient models (UNIQUAC and NRTL) were optimized with particle swarm optimization (PSO), and used to describe the isobaric vaporliquid equilibrium of fifteen binary mixtures containing alcohol water. The results were compared with the LevenbergMarquardt algorithm, and show that the PSO algorithm is a good method to correlate and predict the vaporliquid equilibrium of this type of system. © 2010 Elsevier Ltd. All rights reserved.


Lazzus J.A.,University of La Serena
Mathematical and Computer Modelling | Year: 2013

Seven thermal properties: melting point temperature, boiling point temperature, critical temperature, autoignition temperature, flash point temperature, lower flammability limit temperature and upper flammability limit temperature, were estimated using a hybrid method that includes an artificial neural network (ANN) with particle swarm optimization (PSO). A database of 530 substances was used in the training of this hybrid algorithm. To discriminate the different substances the molecular structures were given as input parameters. Different topologies of the neural network were studied and the best architecture was determined. The optimal condition of the network was obtained adjusting the PSO parameters by trial-and-error. The results show that the proposed ANN+PSO method represent an excellent alternative for the estimation of thermophysic properties with acceptable accuracy. © 2012 Elsevier Ltd.

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