17 resultados para Science and Technology
Resumo:
Thermal degradation of as electrospun chitosan membranes and samples subsequently treated with ethanol and cross-linked with glutaraldehyde (GA) have been studied by thermogravimetry (TG) coupled with an infrared spectrometer (FTIR). The influence of the electrospinning process and cross-linking in the electrospun chitosan thermal stability was evaluated. Up to three degradation steps were observed in the TG data, corresponding to water dehydration reaction at temperatures below 100 ºC, loss of side groups formed between the amine groups of chitosan and trifluoroacetic acid between 150 – 270 ºC and chitosan thermal degradation that starts around 250 ºC and goes up to 400 ºC. The Kissinger model was employed to evaluate the activation energies of the electrospun membranes during isothermal experiments and revealed that thermal degradation activation energy increases for the samples processed by electrospinning and subsequent neutralization and cross-linking treatments with respect to the neat chitosan powder.
Resumo:
The aim of the research is to analyze the different aspects associated with the motivation and benefits of certified ISO 9001 companies in Portugal. A total of 426 certified Portuguese companies were surveyed. The response rate was equal to 61.03 percent. Our results suggest that the main motivation for certification were “improvement of quality”, “improvement of company image”, “marketing advantage”, “give empowerment to workers / capturing workers knowledge” and “cost reduction”. The main benefits that Portuguese companies have gained from the referred certification have been, among others, the improvement of “procedures”, beneficial effect on the “company’s image”, the improvement of quality products/services, increase of the “customer satisfaction”, improvement of “on-time delivery”; improvement the “morale” of workers’ increase in productivity and decrease of “production costs”, among others. The surveyed firms belong only to the Minho region of the north of Portugal. This paper aims to provide a contribution to the research related to the motivation and benefits associated to the quality management systems. The selection of the motives and benefits were validated through statistical analysis and the relationship between expected and perceived benefits was discussed.