ABSTRACT One of the applications in Materials Science carried out at the Center for Technological Applications and Nuclear Development (CEADEN) is the technical support through several methods used, based on applied Physics for the restoration and maintenance of structures and objects holding artistic and social relevance in Havana city. The aim of this paper is to present two examples of X -ray Fluorescence and Diffraction materials characterization, intended to support conservation and restoration activities of the Cuban cultural and historic heritage: analyzed objects were pottery roof tiles for the restoration of the mansion known as The Green House at 5th Avenue, Miramar, as well as pigments from a Cuban fine artist’s canvas and palette.

RESUMEN Una de las direcciones de aplicación de la Ciencia de Materiales que realiza el Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear CEADEN es el apoyo mediante un grupo de técnicas físicas a la restauración y el mantenimiento de estructuras y objetos de la ciudad de La Habana, entre otras localidades de Cuba, que poseen interés artístico y social . En el presente trabajo se abordan varias aplicaciones en la caracterización de materiales para contribuir a las actividades de conservación del patrimonio cultural e histórico cubano que se encuentra en La Habana. Se presentan dos ejemplos de análisis por las técnicas de Fluorescencia de Rayos X y Difracción de rayos X de los pigmentos de obras en lienzos y de la paleta de una reconocida artista de la plástica cubana; así como el de tejas cerámicas que fueron utilizadas en la restauración de los techos de la residencia conocida como Casa Verde de 5ta Avenida en el Municipio Playa.

Polymeric cation exchange membranes (PEMFC) are used in fuel cell technology. These membranes act as a physical barrier between anode and cathode, but diffusion through the membrane should allow protons to be carried from anode to cathode at a rate sufficient to supply energy requirements. They avoid any direct reaction of oxygen and hydrogen that would diminish fuel cell efficiency. Membranes have to be conditioned before use. This conditioning step changes membrane counterions and modifies their water content, which has an effect on their diffusion coefficients. In order to analyse and quantify the effect of conditioning techniques on membrane performance various experiments with Nafion 117 cation exchange membranes were carried out. Membranes were conditioned using various methods to change the charged cation in the membrane. The reactives used were ultrapure water, nitric acid, hydrochloric acid, hydrogen peroxide, sodium chloride, potassium chloride and ethylene glycol, all at room temperature. Some conditioning methods were carried out using solvents heated to 100 ºC. Water content was indirectly monitored by measuring membrane swelling. Results show that membrane conditioning with strong acids followed by treatment with water increases membrane water content by about 5%. Using high-temperature treatment the water content also increases. Water uptake or release from membranes is analysed in terms of water activity.