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Correa G.J.,Luis Amigo University Foundation | Yusta J.M.,University of Zaragoza
Energy Conversion and Management | Year: 2014

In this paper the authors apply methodological strategies for the structural vulnerability assessment in high voltage power networks based upon the combination of power flow models and scale-free graph statistic indexes. Thus, it is possible to study risk scenarios based on events that may trigger cascading failures within a power system. The usefulness of graph theory techniques has been validated on previous works of the authors, and may be applied in analysis of the vulnerability of different power electric networks. A case study for vulnerability analysis is carried out through methodologies that allow comparison on random error and deliberate attack tolerance evaluation in transmission electric systems from countries like Colombia and Spain. Such vulnerability assessment methodology takes into account the current conditions of the power networks (base case), as well as the impact of expansion plans into infrastructures as defined by their governments. Consequently, the authors show the advantage on the use of graph theory based techniques for vulnerability analysis of electrical power systems. © 2013 Elsevier Ltd. All rights reserved. Source

Avendano J.G.,Luis Amigo University Foundation | Ramirez L.M.S.,Minuto de Dios University Corporation
Revista Latinoamericana de Psicopatologia Fundamental | Year: 2016

To understand the practices and the experimental formation of the psychopedagogy of abnormal childhood in Colombia, carried out in the San Jose Juvenile Correctional Facility and Work School, Colombia, between 1914 and 1947. Methods and materials: qualitative study, of a historical-hermeneutic approach, using documentary research, and file heuristics of document heritage and institutional historiography within the study period. Conclusions The emergence of a new special education regime (medical and psychopedagogical) established an important change in the model of punishing reformatory to pedagogical intervention, influenced by crossing scientific doctrines of the late nineteenth and early twentieth centuries, such as the rule of normal and pathological, the degeneration theory and eugenics, for perfecting a modern subject who can be useful to itself and to society. © 2009 University Association for Research in Fundamental Psychopathology. Source

Correa-Henao G.J.,Luis Amigo University Foundation | Yusta J.M.,University of Zaragoza | Lacal-Arantegui R.,European Commission
International Journal of Critical Infrastructure Protection | Year: 2013

This paper describes a methodology for risk identification and risk assessment in electricity infrastructures. The approach leverages risk maps and can be applied to general infrastructure networks. A semi-quantitative assessment strategy that incorporates the creation of risk charts within a risk management framework is also presented. This strategy engages an intuitive graphical representation to identify the most significant threats affecting infrastructure networks. As a result, it is possible to conduct risk analyses of energy supply (and other) infrastructures within a region or country by engaging interconnected risk maps. The application of the methodology is demonstrated using a case study of a Colombian electricity infrastructure, which includes an estimation of the risk components. © 2013 Elsevier B.V. Source

Gomez-Marin A.M.,University of Alicante | Feliu J.M.,Luis Amigo University Foundation
Catalysis Today | Year: 2015

In this paper, the role of surface steps on the electrocatalytic activity of platinum nanostructured surfaces for the oxygen reduction reaction (ORR) in acidic medium is evaluated by using stepped surfaces of structure Pt(S)[n(1 1 1) × (1 1 1)] with large terraces (20≤n≤50). It is realized that the inclusion of an even low amount of surface steps enhances the ORR, and linear activity trends are measured when currents at constant potential are plotted vs. the step density. As a consequence, an ideal ORR curve for a defect-free Pt(1 1 1) surface is extrapolated at zero defect density from experimental data and can be compared to that of a quasi-perfect Pt(1 1 1) electrode. It is clearly shown that surface steps promote the electrode activity toward ORR in acid medium. Results are discussed in light of available theoretical and experimental data. © 2014 Elsevier B.V. All rights reserved. Source

Ferraro F.,Luis Amigo University Foundation | Perez-Torres J.F.,Free University of Berlin | Hadad C.Z.,University of Antioquia
Journal of Physical Chemistry C | Year: 2015

The electronic and structural details for the acetylene selective catalytic activation by one of the few small gold clusters whose experimental gas-phase initial geometry in neutral charge state is known, the gold heptamer, are investigated. Doing an exhaustive search of the acetylene-gold heptamer ZORA scalar relativistic PW91/TZ2P configurational space, we determine the main, secondary, and also the unimportant structures relative to the catalytic activation. We found that the leading mechanism of activation consists in the tendency to the disappearance of one of the acetylene π bonds at the expense of the formation of C-Au strong interactions, by the predominant dative interaction of s/d-like gold heptamer molecular orbitals toward a π∗ orbital of acetylene. This results in adducts having very diminished energy barriers toward processes such as, for example, the selective hydrogenation reaction to ethylene. This activation would occur with a considerable change of the participant species geometries and, with the formation of a frontier single occupied molecular orbital, very localized at carbon atoms region. © 2015 American Chemical Society. Source

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