A importância da educação sexual em meio escolar

Em Portugal existe legislação referente à educação sexual em meio escolar desde 1984. A mais recente é de agosto de 2009. Este estudo pretende perceber se esta lei está a ser cumprida num Agrupamento de Escolas do norte do país e quais as principais dúvidas, relacionadas com a sexualidade, que os adolescentes apresentam. Para isso foi aplicado um questionário a 274 alunos (46.4% de rapazes e 53.6% de raparigas), entre os 10 e os 20 anos de idade (média = 13.7%). O estudo permitiu concluir que a maioria (75.4%) concorda com aulas de educação sexual nas escolas, no entanto, do total da amostra, 59.0% nunca tiveram aulas de educação sexual. Também se percebeu que grande parte não fala nunca destes assuntos com os pais (34.1%). As dúvidas relacionadas com a temática são variadas (desde as mudanças na adolescência, às doenças sexualmente transmissíveis ou aos métodos contracetivos, passando pela relação que estes jovens estabelecem com os pais e amigos), pelo que se torna necessária e urgente a aplicação da atual legislação sobre a educação sexual nas escolas do nosso país.

Chemical resistance of lime-based grouts for masonry strengthening

The stone masonry walls are present in many buildings and historical monuments, with undeniable asset value, but also in old buildings housing both in Portugal and in Europe. Most of these buildings in masonry are in certain cases in a high state of degradation needing urgent intervention. This requires the identification of deficiencies and the application of appropriate intervention techniques. One of the possible techniques for structural consolidation works of stone masonry walls is the injection of fluid mortars currently called grouts. The choice of grouts is very important with regard in particular to their chemical and physical properties. In this study, carried out under the Master of Chemical Engineering, two types of lime-based grouts were used, in order to evaluate and compare their chemical resistance due to the crystallization of soluble salts. One of the grouts is a pre-dosed blend commercially available, Mape-Antique I from company Mapei (CA), and the second grout is a mixture prepared in the laboratory (LB), comprising metakaolin, cement, hydrated lime, water and superplasticizer. With the purpose of evaluating the action of sulphates on these grouts, a series of samples underwent several wetting-drying cycles using two different temperatures, 20 °C and 50 °C. During the experiment it was determined the change of weight and compressive strength in the analyzed grouts, as well as the sulphate ion concentration and pH of the solution in which the samples were dipped. The commercial grout (CA) apparently has a greater chemical resistance to sulphates. However grout LB showed to have positive results in some parameters.

CO2 capture by adsorption in post combustion processes

Global concentration of CO2 in the atmosphere is increasing rapidly. CO2 emissions have huge impact on global climate change. Therefore, efficient CO2 emission abatement strategies such as Carbon Capture and Storage (CCS) are required to combat this phenomenon. There are three major approaches for CCS: - Post-combustion capture; - Pre-combustion capture; - Oxyfuel process. Post-combustion capture offers some advantages in terms of cost as existing combustion technologies can still be used without radical changes on them. This makes post-combustion capture easier to implement as a retrofit option compared to the other two approaches. Therefore, post-combustion capture is probably the first technology that will be deployed on a large scale. The aim of this work is to study the adsorption equilibrium of CO2, CH4 and N2 in zeolite 5A at 40ºC. For this, experiments were performed to determine the isotherms of adsorption of CO2, CH4 and N2 near 40ºC with the conditions of the post-combustion capture processes. It has been found that the 5A zeolite adsorbs a significant quantity of CO2 values of about 5 mol/kg at a pressure of 5 bar.