Papers by Author: Ramón Artiaga

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Authors: Angel Varela, Ana García, José Luís Mier, Ramón Artiaga, Fernando Barbadillo, L. García
Authors: Rosa Losada, Fernando Barbadillo, Ramón Artiaga, Ana García, José Luís Mier, L. García
Authors: Ramón Artiaga, Angel Varela, José Luís Mier, Ana García, Rosa Losada, Salvador Naya
Authors: Salvador Naya, Ricardo Cao, Ramón Artiaga, Ana García
Abstract: The application of nonparametric method of functional regression for the classification of different types of materials studied by thermo-gravimetric analysis is proposed in this work. The method is illustrated with two case studies for classifying different materials. Some simulation study shows the performance of the method when the correlation between groups parameters and the error variance change.
Authors: Rosa Losada, José Luís Mier, Fernando Barbadillo, Ramón Artiaga, Angel Varela, Salvador Naya
Abstract: A diglycidyl-ether of bisphenol-A (DGEBA)/Triethylenetetramine (TETA) system was studied by non-isothermal differential scanning calorimetry (DSC) to establish its kinetics of cure. The DGEBA resin was Araldite GZ 601 X75 used in the marine coatings formulations. Previously, the optimum resin/hardener ratio was determined by the reaction heat measuring (.Hc) calculated from the curing exothermic peak. Tests at different heating rates (10, 15, 20, 25 and 30°C/min) under inert atmosphere were carried out in order to study the reaction kinetics. The activation energy of the cure (Ea) was obtained from these tests data by Borchardt-Daniels, autocatalytic, Duswalt and isoconversional Ozawa methods. Once the activation energy was determined, the master curves method was applied to find the kinetic model which best describes the measured DSC data. The Sestak-Berggren model SB (m,n) was found to be the most adequate for the system studied.
Authors: Fernando Barbadillo, A. Fuentes, Salvador Naya, Ricardo Cao, José Luís Mier, Ramón Artiaga
Abstract: The logistic mixture model was successfully studied previously in the separation of overlapping steps in some polymeric systems by the authors. In the present work, this method is applied to a polyesther-polyurethane degradation under air and inert atmospheres at several heat rates (5, 10, 15, 20 and 25 °C/min) in dynamic TGA. Every logistic component is fitted by reaction order, Johnson-Mehl-Avrami and Sestak-Berggren kinetics equations in order to calculate its kinetic parameters (activation energy, frequency factor and exponents). The reaction order model gives a good fitting and reproduces accurtelly the experimental curves. Johnson-Mehl-Avrami and Sestak- Berggren equations resulted to be not suitables because of the activation energy values obtained.
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