RESUMO
A new paradigm for energy is underway demanding decarbonized energy systems. Some of them rely on emerging electrochemical devices, crucial in hydrogen technologies, including fuel cells, CO2 and water electrolysers, whose applications and performances depend on key components such as their separators/ion-exchange membranes. The most studied and already commercialized Nafion membrane shows great chemical stability, but its water content limits its high proton conduction to a limited range of operating temperatures. Here, we report the synthesis of a new series of triazinephosphonate derivatives and their use as dopants in the preparation of new modified Nafion membranes. The triazinephosphonate derivatives were prepared by substitution of chlorine atoms in cyanuric chloride. Diverse conditions were used to obtain the trisubstituted (4-hydroxyphenyl)triazinephosphonate derivatives and the (4-aminophenyl)triazinephosphonate derivatives, but with these amino counterparts, only the disubstituted compounds were obtained. The new modified Nafion membranes were prepared by casting incorporation of the synthesized 1,3,5-triazinephosphonate (TPs) derivatives. The evaluation of the proton conduction properties of the new membranes and relative humidity (RH) conditions and at 60 °C, showed that they present higher proton conductivities than the prepared Nafion membrane and similar or better proton conductivities than commercial Nafion N115, in the same experimental conditions. The Nafion-doped membrane with compound TP2 with a 1.0 wt % loading showed the highest proton conductivity with 84 mS·cm-1.
RESUMO
Este trabalho procura analisar a relação entre a atividade laboral e os processos de avaliação cognitiva em bombeiros portugueses. Participaram do estudo 163 bombeiros do distrito do Porto, em Portugal. O protocolo de avaliação incluiu medidas de avaliação cognitiva, stress, burnout, satisfação com a vida e comprometimento organizacional. Os resultados mostraram que 32,5% dos bombeiros descreveram elevados níveis de stress ocupacional, não tendo sido assinalado nenhum caso de burnout pleno. As análises comparativas demonstraram uma experiência profissional mais negativa em profissionais que avaliaram o trabalho como mais ameaçador e menos desafiante e naqueles com menor potencial de confronto para lidar com as exigências do trabalho. As análises de regressão apontaram o valor preditivo das dimensões de stress e de avaliação cognitiva na explicação da experiência de burnout. No final do trabalho, discutem-se as implicações dos processos de avaliação cognitiva na compreensão da adaptação humana em contextos laborais.
This study analyzes the relationship between professional occupation and the processes of cognitive appraisal in Portuguese firefighters. The study involved 163 firemen from Oporto region, in Portugal. The evaluation protocol included measures of cognitive appraisal, stress, burnout, organizational commitment, and life satisfaction. The results revealed very significant levels of occupational stress (32.5%), although no case of "full" burnout was detected. The comparative analysis showed a more negative work experience in professionals who assessed their activity as more threatening, less challenging and with a less potential for confrontation with the work demands. The regression analysis showed the predictive value of the stress dimensions and the processes of cognitive appraisal in explaining the experience of burnout. Finally, we discuss some of the implications of cognitive appraisal processes in understanding human adaptation in workplace settings.
Este estudio analiza la relación entre la actividad laboral y los procesos de evaluación cognitiva en bomberos portugueses. Participaron del estudio 163 bomberos del distrito de Porto. El protocolo de evaluación incluyó medidas de evaluación cognitiva, estrés ocupacional, burnout, satisfacción con la vida y compromiso organizacional. Los resultados mostraron que el 32.5% de los bomberos presentaron altos niveles de estrés laboral aunque no se haya señalado ningún caso de burnout pleno. Los análisis comparativos revelaron experiencias laborales más negativas en aquellos profesionales que evaluaron el trabajo como más amenazante y menos desafiante y en aquellos con menor potencial para hacer frente a las exigencias del trabajo. Los análisis de regresión mostraron el valor predictivo de las dimensiones de estrés y de la evaluación cognitiva para explicar la experiencia de burnout. Se discuten las implicaciones de los procesos de evaluación cognitiva en la comprensión de la adaptación humana en contextos de trabajo.