João Fernandes

Synthesis of fatty acid methyl esters via direct transesterification with methanol/carbon dioxide mixtures from spent coffee grounds feedstock

The feasibility of in situextraction and transesterification of spent coffee ground oil into fatty acid methyl esters with supercritical methanol has been investigated in the temperature range 473–603 K, and in the pressure range 10.0–30.0 MPa. At 30.0 MPa and 603 K, a fatty acid methyl esters (FAME) yield of 84.9% was obtained. Carbon dioxide was added to methanol with the aim of reducing the operating temperature and pressure. It was demonstrated that at a reaction temperature of 573 K, pressure of 10.0 MPa and a CO2/MeOH molar ratio of 0.11, a FAME yield of 93.4% was obtained.

Development and characterization of a thermoresponsive polysulfone membrane using an environmental friendly technology

A new and environmentally friendly technology has been used successfully to produce thermoresponsive polysulfone membranes with good performance in terms of valve mechanism in the pores, with a complete on-off control of water permeability. Membranes were prepared using a CO2-assisted phase inversion method and their pores were coated/impregnated with a thermoresponsive polymer – poly(N-isopropylacrylamide) – using a new methodology for the preparation of these type of structures. The coating/impregnation efficiency was assessed by SEM and XPS analysis that confirmed the presence of nitrogen due to the thermoresponsive hydrogel. Contact angle measurements and phosphate buffer solution permeability were determined in order to characterize the structure hydrophobicity variations with temperature. The on-off mechanism was tested using a model protein (BSA) as a proof of concept for the ability to control pore apertures by temperature stimulus. A diffusion model based on Ficks law and Langmuir adsorption was developed.

Practical application of spatial ecosystem service models to aid decision support

Highlights • A structured protocol for adapting a spatial ecosystem service model to local contexts is proposed.• Decision context, the final users and uses of maps should drive the way the spatial ecosystem service models are structured.• Simply increasing spatial resolution is not sufficient to increase legitimacy and the ultimate utility of maps.• The type and level of stakeholders’ involvement is a determinant of spatial model usefulness.

Modelling and Simulation of a Complete Supercritical Fluid Extraction Plant with Countercurrent Fractionation Column

The most complete dynamic model to date of a supercritical fluid extraction (SFE) plant is presented and experimentally validated. The SFE flowsheet is modularly organized into a set of detailed sub-models of the main unit operations, including the extraction packed column, the supercritical solvent heat exchanger, the product recovery and solvent regeneration column, and the solvent make-up. The modules are interconnected through appropriate boundary conditions that establish continuity of mass, momentum, and energy. The present model significantly improves our previous modeling efforts by, among other features, including the gas compressor unit, extending the operation of the whole plant to nonisothermal conditions, and upgrading the packed column model for reflux mode operation. The SFE model was validated against experimental data for the fractionation of edible oil mixtures by supercritical carbon dioxide. Good agreement was obtained between experimental and predicted results; moreover, the model correctly predicts the trends with different operating and design parameters.

Mudar de casa em Lisboa: perfis socioeconômicos da recente mobilidade residencial

As mudancas que tem ocorrido recentemente na cidade de Lisboa estao associadas, em grande medida, as dinâmicas de mobilidade residencial, suas causas e consequencias. A escolha da area de residencia, determinada por fatores economicos, sociais, culturais e psicologicos, resulta numa alteracao gradual da estrutura social da cidade e dos padroes de ocupacao do territorio. Este artigo, partindo dos dados de um inquerito realizado aos municipes de Lisboa entre 2016 e 2017, procura contribuir para melhor compreender essas mudancas, analisando as dimensoes territorial e temporal da mobilidade, assim como os perfis socioeconomicos dos residentes mais antigos e dos novos. Perante a diversidade de experiencias de mobilidade residencial, recorreu-se a analise multivariada para definir cinco perfis com caracteristicas sociais distintas.