Simulador de Carga Mecânica, em Tempo Real, para Accionamento Eléctrico

O objectivo deste trabalho é implementar um simulador, em tempo real, de carga mecânica por forma a aferir os diferentes comportamentos de uma máquina eléctrica em função do tipo de carga a accionar. O protótipo desenvolvido permite ensaiar o comportamento de qualquer tipo de máquina rotativa, inserida num accionamento eléctrico, para vários tipos de carga mecânica. De forma a estudar o comportamento de uma máquina eléctrica para um conjunto alargado de cargas mecânicas foram implementadas várias cargas típicas, cujo binário de carga pode depender do tempo ou da velocidade. São apresentadas características de implementação do sistema desenvolvido, que faz uso de um travão magnético e de um autómato programável, e resultados experimentais obtidos para vários tipos de carga

Transmission lines protection based on the current eigenvalues differential concept

This work presents a new approach for a current differential protection of the transmission lines. The proposed approach is based on the Clarke-Concordia transformation and principal component analysis. First the acquired current signals are transformed into “αβo” components by applying the Clarke-Concordia transformation. This allows obtaining typical patterns. To identify these patterns a principal component analysis is performed. Several tests under different fault conditions were performed. The obtained results allow verifying the effectiveness of the proposed approach

Hyaluronic acid/poly-L-lysine bilayered silica nanoparticles enhance the osteogenic differentiation of human mesenchymal stem cells

First published online 15 Aug 2014Herein, we evaluate the influence of a PLL–HA bilayer on the surface of silica nanoparticles on their capacity to induce the osteogenic differentiation of human bone marrow stem cells (hBMSCs), as a function of their concentration (50 μg mL−1, 25 μg mL−1 and 12.5 μg mL−1). To this purpose, we synthesized silica nanoparticles (diameter of 250 nm; ζ-potential of −25 mV) that were coated with PLL–HA (diameter of 560 nm; ζ-potential of −35 mV). The cell viability, cell proliferation, protein quantification (i.e. MTS, DNA and ALP, respectively) and gene expression (of osteogenesis-related genes: ALP, osteocalcin, collagen type I, bone sialoprotein, Runx-2, osteopontin and osterix) were monitored, for 21 days. We observed the overexpression of most of the tested osteogenic transcripts in the hBMSCs cultured with SiO2–PLL–HA, at concentrations of 25 μg mL−1 and 12.5 μg mL−1. These results indicate that the proposed nanoparticles temporarily improve the osteogenic differentiation of hBMSCs at low nanoparticle concentrations.We acknowledge funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number REGPOT-CT2012-316331-POLARIS. AM acknowledges QREN (project "RL1-ABMR-NORTE-01-0124-FEDER-000016" co-financed by the North Portugal Regional Operational Programme (ON. 2, "O Novo Norte") under the NSRF through the ERDF) for financing this research work

RenH₂ — A Stand-Alone Sustainable Renewable Energy System

Non

Feeding behaviour of Barbus Bocagei assessed under a spatio-temporal approach

The feeding behaviour of Barbus bocagei was assessed in a lowland system by a two years survey Of two contrasting sites also talking into account, for the first time diurnal changes of fish diet and benthos availability

Pulmonary lesions consistent with disseminated adiaspiromycosis in egyptian mongooses (Herpestes ichneumon) from Portugal.

Pulmonary lesions consistent with disseminated adiaspiromycosis in egyptian mongooses (Herpestes ichneumon) from Portugal

ENZYMATIC MONITORIZATION OF MURAL PAINTINGS BIODETERIORATION

Biodeterioration of mural paintings by microorganisms is an important research field that needs novel approaches to fully understand the mechanisms and effects. In this work, the presence of microorganisms and their biological activity were investigated by extra and intracellular enzymatic monitorization. The enzymes arylsulphatase, β-glucosidase, dehydrogenase and phosphatase were used as biomarkers of the microbial metabolic activity, and the viability cellular assays revealed a relationship with the degradation levels of the paintings. In this way, the metabolic activity of the microbial population can be correlated with the contamination levels detected and with biodeterioration status of the paintings. Therefore, enzymatic approaches constitute good biomarkers to be applied in this research field and are useful to detect biodeteriogenic agents