Artículos SCI

Colour analysis appears to be a robust technique for characterizing vitamin E doping and gamma irradiation of medical grade polyethylene samples. The analysis procedure described in this paper is of great interest because it can easily distinguish between polyethylene samples with differences in vitamin E (α-tocopherol) doping of about 0.1 wt% and gamma irradiation doses of 30 kGy. It is found that the colour differences (with respect to untreated samples) induced by gamma irradiation and/or vitamin E doping add-up linearly. This method for detecting the presence of vitamin E is fast, simple and non-destructive.

Prof. Andrés Ortega passed away on last January after a painful and long illness. He was Professor of Inorganic Chemistry at the University of Seville (Spain) and was an outstanding researcher in the field of solid state reaction kinetics, an area to which he devoted his entire career since 1983, when he submitted his PhD thesis entitled ‘Critical study of non-isothermal methods for the kinetic analysis of solid-state reactions’. During his post doc stage and collaboration with Prof. Jean Rouquerol, his interest was raised by the Sample Controlled Thermal Analysis (SCTA) technique and its application to the kinetic study of solid state reactions, this latter one developed in Seville along with Prof. José Manuel Criado. A paper from this period should be highlighted: ‘Correlation between the shape of controlled-rate thermal analysis curves and the kinetics of solid-state reactions’ [Thermochimica Acta 157 (1990) 171], the most cited one in his research career. Most of his scientific production was published in Thermochimica Acta and in the Journal of Thermal Analysis and Calorimetry. A tireless professional, he remained active until a few weeks before dying. Being seriously ill he developed a method for the kinetic analysis of reactions with variable activation energies that notably simplifies the previous one proposed by Vyazovkin. The results were published in Thermochimica Acta under the title ‘A simple and precise linear integral method for isoconversional data’ [Thermochim. Acta 474 (2008) 81]. The high number of citations of this article – according to the ISI WEB of Knowledge – in spite of the short time elapsed since it was published reveals its impact within the scientific community.

He was also very much involved in teaching duties, developing new subjects and applying new teaching methodologies. He chaired two important academic positions at the University of Seville related to his works on teaching and educational sciences, as Director of the Institute of Educational Science and as Chairman of the Committee on Education of the University.

Though he sometimes appeared to be reserved, Andrés was a kind man, always ready to help in any problem that was presented to him. With a critical attitude and many cultural interests, he had a vast knowledge and a great ability to interpret the most diverse questions, frequently presenting a reasoning alternative to those commonly established. This was a continuous source of enrichment for both his friends and colleagues, who never will forget him.