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Eibar, Spain

Verdia P.,University of Vigo | Hernaiz M.,Tekniker | Gonzalez E.J.,University of Porto | Macedo E.A.,University of Porto | And 2 more authors.
Journal of Chemical Thermodynamics | Year: 2014

The knowledge of the physical properties of ionic liquids is of high importance in order to evaluate their potential applicability for a given purpose. In the last few years, ionic liquids have been proposed as promising solvents for extractive desulfurization of fuels. Among them, recent studies have shown that ionic liquids derived from pyridinium affords excellent S-compounds removal capacity. In this work, the thermal analysis of five ionic liquids derived from pyridinium cation polysubstituted with different alkyl chains was carried out by Differencial Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA). Furthermore, the density, speed of sound, refractive index and dynamic viscosity for all the pure ionic liquids were also measured from T = (298.15 to 343.15) K. The effect of the number of cation alkyl chains, their length, and their position on the pyridinium ring, on the ionic liquid physical properties is also analyzed and discussed. © 2013 Elsevier Ltd. All rights reserved. Source


De Las Cuevas F.,University of Navarra | Reis M.,University of Lisbon | Ferraiuolo A.,CSM | Pratolongo G.,Duferco la Louviere | And 3 more authors.
Advanced Materials Research | Year: 2010

Hot rolled, laboratory-cast, TWIP steel samples (5.4 mm thick) of 22% Mn - 0.6% C (in mass-%) were cold rolled to different reductions (from 40 % to 70 %) and subsequently isothermally annealed for various times at temperatures ranging from 450° C to 1100° C. The evolution of recrystallization and grain growth was followed by control of the softening kinetics complemented by metallographic, OIM and microtexture observations. A map of the recovery, recrystallization and grain growth in the temperature-time space was obtained. In all instances, the grain size at the end of recrystallization was very fine, D ≤ 2 μm and larger grain sizes were the result of grain growth. A range of grain sizes 2 μm ≤ D ≤ 50 μm was covered by the grain growth experiments. A phenomenological grain growth equation that is useful for the annealing control of this steel was derived from the measurements. © (2010) Trans Tech Publications. Source


Sedano A.,MTOI | Sancibrian R.,University of Cantabria | De Juan A.,University of Cantabria | Viadero F.,University of Cantabria | Egaa F.,Tekniker
Mathematical Problems in Engineering | Year: 2012

A hybrid optimization approach for the design of linkages is presented. The method is applied to the dimensional synthesis of mechanism and combines the merits of both stochastic and deterministic optimization. The stochastic optimization approach is based on a real-valued evolutionary algorithm (EA) and is used for extensive exploration of the design variable space when searching for the best linkage. The deterministic approach uses a local optimization technique to improve the efficiency by reducing the high CPU time that EA techniques require in this kind of applications. To that end, the deterministic approach is implemented in the evolutionary algorithm in two stages. The first stage is the fitness evaluation where the deterministic approach is used to obtain an effective new error estimator. In the second stage the deterministic approach refines the solution provided by the evolutionary part of the algorithm. The new error estimator enables the evaluation of the different individuals in each generation, avoiding the removal of well-adapted linkages that other methods would not detect. The efficiency, robustness, and accuracy of the proposed method are tested for the design of a mechanism in two examples. Copyright © 2012 A. Sedano et al. Source


Arnaiz A.,Tekniker | Ferreiro S.,Tekniker | Buderath M.,Airbus
Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability | Year: 2010

This paper details a new decision support that adds a proactive function to the actual line aircraft maintenance turn-around-time (TAT) process, where next-flight decisions are assisted by the health assessment function of the integrated vehicle health management (IVHM) of an aircraft. The 'operational risk assessment' concept appears an extended function supported on the IVHM information for calculating and evaluating the operational risk for aircraft and fleet operations. It creates or reshapes maintenance plans based on predictions of the future maintenance relevant events (e.g. component-degradation-driven repair or replacement events) and its impact on the operational planning of the aircraft/fleet. 'Operational risk assessment' makes it possible to turn the scheduled line maintenance into a proactively defined maintenance. The paper also illustrates the first step involved in this approach: 'condition view' function, which is responsible for the provision of the remaining useful life (RUL) prediction of a health managed component. This function provides the basis for the operational risk estimation on the aircraft in order to identify maintenance actions that can be deferred. Source


Navarro-Fuster V.,University of Alicante | Calzado E.M.,University of Alicante | Boj P.G.,University of Alicante | Quintana J.A.,University of Alicante | And 7 more authors.
Applied Physics Letters | Year: 2010

An efficient, low-cost, and highly photostable second-order distributed feedback (DFB) laser, fabricated by thermal nanoimprint lithography and based on a polymer active film containing a perylenediimide derivative, is reported. It shows a photostability half-life of 3.1× 105 pump pulses (>8 h), when pumped at the same spot of the film. This value is the highest reported to date for organic DFB lasers measured under ambient conditions. The device emits at 573 nm, matching the second low-loss transmission window of poly(methylmethacrylate) (460-590 nm), thus offering potential for applications in data communications based on polymer optical fibers. © 2010 American Institute of Physics. Source

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