Viscosity of R134a, R32, and R125 at saturation

This paper reports the results of the measurement of the viscosity of R134a close to the saturation line in the vapor phase. The new measurements were carried out in a vibrating-wire viscometer specially constructed for the purpose, and the results have an accuracy of ±2%. In addition, the opportunity is taken to present a reevaluation of earlier measurements along the saturation line of the viscosity of R32 and R125. Improved equations of state for these fluids are now available and can be employed to generate improved values for the viscosity

Sustainability literacy in older age groups: on the way to sustainable development

Conferência internacional realizada em Bogotá, Colombia, de 14-16 de junho de 2017The world is facing sustainability challenges for which actions and results are needed in a 10 to 15 years time frame. Sustainability Literacy or Education has a crucial role for the Sustainable Development and is a set of different forms of education aiming to create economic, social, cultural and environmental conditions for sustainable development. This study looks at Sustainability Literacy or Education for Sustainable Development as a potential tool to empower individuals and communities to make more informed decisions that are aligned with long-term sustainability goals and can produce the short-term results needed. Any Education for Sustainable Development initiative relies and can greatly benefit from a bottom-up approach in local communities. An active participation of individuals in the community initiatives generates more opportunities for formal and non-formal lifelong learning and creates relevance that is engaging for other community members. The traditional approach of investment in Sustainability Literacy focuses on youth. However, while this approach is important in the long run, it may not yield results for current sustainability challenges. Older age groups (i.e. 50 or older), usually overlooked because they are perceived as not being motivated by sustainability or as being too late in their life span to have a significant impact, may play a crucial role in promoting sustainability within communities. Our study addresses the importance of improved sustainability literacy in older age groups (i.e. 50 or older) as a driver for sustainability. Endorsing a new role for senior citizens, by leveraging their last active years for short term sustainability efforts, we also empower them with the knowledge and tools to raise the sustainability literacy in younger generations. This work is being carried out in a Lisbon suburban community of around 12000 people, half of which are over 50 years old, and analyses some reflections on the importance of sustainability literacy within this age group and its effects on other age groups. It should be stressed that this population of 50+ years of age is actively engaged with the local University of the 3rd Age (U3A), where topics are presented and discussed in the classroom, using videos to generate a guided discussion toward the construction of the concepts by the students. The results from a group attending a life science literacy class show that the students experience increased personal satisfaction and wellbeing, are motivated towards learning and knowledge sharing within families and communities, including younger generations. These students also expressed greater understanding of messages from the media, health professionals and care takers, as well as a more positive health self-assessment and a greater treatment adherence. These results, aligned with the targets for good health and well-being sustainable development goal (SDG) suggest that initiatives to increase literacy lead to immediate behavior changes and knowledge dissemination. Further studies are ongoing regarding other SDGs, such as climate action, responsible consumption and production or affordable and clean energy.FCT - Fundação para a Ciência e Tecnologia, Ministério da Ciência, Tecnologia e Ensino SuperiorN/

Mutual diffusivity in n-Heptane + n-Hexane isomers

A preliminary study of the effect of branching in the binary diffusion of hexane isomer + n-heptane systems is presented. Measurements have been performed with an instrument modeled for the Taylor dispersion technique, at several compositions, at 297 K, for the n-hexane + n-heptane and 2,2-dimethylbutane + n-heptane binary mixtures. The accuracy is estimated to be 1%. The influence of branching is discussed. It was found that the rough hard sphere model for binary diffusion can reproduce the experimental data within 6%. This model was used to predict the binary diffusion coefficients in the 2-methylpentane + n-heptane and 3-methylpentane + n-heptane mixtures, with an estimated accuracy of 5%

Química geral : velocidade das reacções

Académico - LicenciaturasA velocidade das reações químicas e a lei da velocidade de uma reação. A equação de Arrhenius e sua confirmação experimental. Através de animação gráfica simulam-se colisões entre moléculas

Química geral : reactividade química

Académico - LicenciaturasO vídeo trata as reações de oxiredução e as reações de complexação. São explicados e exemplificados os conceitos de redutor, oxidante, elemento de pilha e pilha eletroquímica

Desafiando o paradigma do ensino da química: o contributo da Universidade Aberta de Portugal

A Universidade tem, ao longo dos anos, mantido uma enorme capacidade para se transformar e adaptar à evolução do Mundo e esse sentido de mudança é também plasmado na constante procura de novos caminhos, novas ideias e novas soluções. Pretende-se com este artigo apresentar o modelo pedagógico da Universidade Aberta – universidade pública portuguesa de ensino a distância – e em particular a sua aplicação ao ensino da química em contexto de e-learning e no âmbito do curso de 1º ciclo em Ciências do Ambiente. São apresentadas as diferentes estratégias que têm vindo a ser desenvolvidas, nomeadamente o recurso a trabalho experimental, o acesso a laboratórios virtuais e a disponibilização de feedback para as atividades formativas e avaliativas.The University has over the years maintained an enormous capacity to transform and adapt to changes in the world and this sense of adjustment is also in the constant search for new paths, new ideas and new solutions. This article aims to present the pedagogical model of Universidade Aberta (Portugal), the public distance learning university and in particular its application to teaching of chemistry in the e-learning context and within the first cycle programme in Environmental Sciences. Different strategies have been applied and implemented, including the use of experimental work, access to virtual labs and the provision of feedback to the training and evaluation activities.info:eu-repo/semantics/publishedVersio

Projeto UNESP, UAb e CAPES: formação de mediadores pedagógicos digitais para a educação a distância

Este trabalho é fruto do protocolo e parceira realizados entre a Universidade Aberta, Portugal, a Universidade Estadual Paulista “Júlio de Mesquita Filho” – UNESP e a CAPES do Brasil. Como resultado dessa parceria, várias colaborações estão ocorrendo entre as instituições e, dessa forma, o fortalecimento dos laços de internacionalização no âmbito da Lusofonia e na área da Educação a Distância. A presente publicação reúne um conjunto de reflexões originárias da proposta didático-pedagógica originária da experiência das instituições mencionadas para a formação de mediadores pedagógicos digitais na educação a distância e a sua concretização mediante a construção, implementação e avaliação de um curso de tutores para o sistema da educação a distância brasileiro.info:eu-repo/semantics/publishedVersio

Mutual diffusivity in binary mixtures of n-heptane with n-hexane isomers

This paper presents a study of the influence of branching in the binary diffusion coefficients of n-heptane+n-hexane isomers, in the liquid state. The measurements have been made with the Taylor dispersion technique, at several compositions, at 283 and 298 K, for the X+n-heptane mixtures, where X=n-hexane, 3-methylpentane, 2, 3-dimethylbutane, and 2, 2-dimethylbutane. The results show a very interesting behavior of the composition dependence of the binary diffusion coefficients, presenting a maximum, for compositions about a molar fraction of n-heptane of 0.5, which increases with the increase in the degree of branching, suggesting the possibility of order~tisorder effects caused by stereochemically favored packing in the liquid phase and energetically favored segment interaction in the liquid mixtures. An attempt to apply the van der Waals model to these data could not predict the experimental binary diffusion coefficients of these systems within the experimental accuracy

E-Sustainability 2017 : Seminário Doutoral do Doutoramento em Sustentabilidade Social e Desenvolvimento

info:eu-repo/semantics/publishedVersio