Integração monolítica de conversores comutados CC-CC de comutação suave: soluções de projecto e simulações

A inclusão de circuitos de gestão de energia dentro dos SoC ainda se encontra em pleno desenvolvimento. Neste contexto é apresentado um primeiro estudo sobre topologias de conversores ressonantes tendo como objectivo a sua integração monolítica em tecnologia CMOS. Um novo método de projecto para conversores Quasi-Square-Wave de alta frequência para integração em tecnologia CMOS é apresentado. O Trabalho de simulação baseado em modelos da tecnologia CMOS 0,35μm revelou problemas distintos para esta topologia de comutação suave em relação à implementação discreta. Dois Conversores QSW de comutação no zero de tensão foram projectados e simulados, um para uma frequência de comutação na ordem da centena de MHz e outro na ordem das dezenas de MHz, utilizando o método apresentado. Os resultados de simulação são analisados, novas direcções para trabalho futuro e melhoramentos para o novo método de projecto são propostos, tendo em conta os problemas identificados.info:eu-repo/semantics/publishedVersio

Load-carrying capacity test of a long-span timber truss

The aim of this work was to study the behavior of existing timber trusses in order to improve the knowledge that may support engineers in the definition of more adequate restoration interventions in old buildings, particularly of long-span timber structures, as industrial or monumental constructions. For this purpose, a cyclic load-carrying test was carried out on a full-scale timber planar truss rescued from an old industrial roof structure. Before the tests, an accurate geometrical characterization was performed and the biological condition of the timber elements was evaluated by non-destructive tests to determine their effective cross-section. The results of the destructive load-carrying test were used to calibrate a numerical model which aimed to assess the effect of the effective cross-sections of the truss components and the axial stiffness of the joints on the overall response observed during loading. The full-scale test performed proved the importance of those kind of tests in order to assess the behavior of existing timber trusses. It is essential to assess the damage of the joints and to model correctly their behavior so as to numerically reproduce the overall behavior of timber trusses

Phylogenetic analysis and genetic diversity of the xylariaceous ascomycete Biscogniauxia mediterranea from cork oak forests in different bioclimates

Cork oak is a tree species with ecological importance that contributes to economic and social development in the Mediterranean region. Cork oak decline is a major concern for forest sustainability and has negative impacts on cork oak growth and production. This event has been increasingly reported in the last decades and seems to be related with climate changes. Biscogniauxia mediterranea is an endophytic fungus of healthy cork oak trees that turns into a pathogen in trees weaken by environmental stress. Understanding the drivers of B. mediterranea populations diversity and differentiation is expected to allow a better control of cork oak decline and preserve forest sustainability. Endophyte isolates from different cork oak forests were identified as B. mediterranea and their genetic diversity was evaluated using phylogenetic and microsatellite-primed PCR analyses. Genetic diversity and variability of this fungus was correlated with environmental/phytosanitary conditions present in forests/trees from which isolates were collected. High genetic diversity and variability was found in B. mediterranea populations obtained from different forests, suggesting some degree of isolation by distance. Bioclimate was the most significant effect that explained the genetic variability of B. mediterranea, rather than precipitation or temperature intensities alone or disease symptoms. These findings bring new implications for the changing climate to cork oak forests sustainability, cork production and quality.This work was supported by FEDER funds through COMPETE (Programa Operacional Factores de Competitividade) and by national funds by FCT (Fundação para a Ciência e a Tecnologia) in the framework of the project POCI-01-0145-FEDER-028635, as well as for financial support to BioISI (UIDB/04046/2020), CBMA (UIDB/04050/2020), and CIMO (UID/AGR/00690/2020) by national funds by FCT/MCTES/PIDDAC. D. Costa thanks FCT for PhD grant SFRH/BD/120516/2016.info:eu-repo/semantics/publishedVersio

Synthesis, structure and non-linear optical properties of L-argininium perrhenate crystal

A new hybrid organic–inorganic non-linear optical crystalline material, L-argininium perrhenate has been synthesized. The crystal belongs to P212121 space group, has a good optical quality and high transmission in the visible and near infra-red spectral regions. L-argininium perrhenate has high birefringence and is more than four times as efficient as KDP in second harmonic generation, making it a potentially attractive material for non-linear optical applicationsThis work was financially supported by the European Regional Development Fund (ERDF) through Programa Operacional Factores de Competitividade (COMPETE: FCOMP-01-0124-FEDER-014628) and the Portugal Fundacao para a Ciencia e Tecnologia (PTDC/CTM-NAN/114269/2009, PTDC/CTM/105597/2008 and Pest-C/FIS/UI0036/2011)

Contribuição para o conhecimento biológico das águas interiores da Graciosa

XI Expedição Científica do Departamento de Biologia - Graciosa 2004.Das três pequenas lagoas permanentes existentes na ilha até meados do século passado, duas desapareceram e a terceira está completamente artificializada. Neste momento as zonas húmidas dulçaquícolas naturais da ilha Graciosa reduzem-se a dois pequenos charcos (Barreiro e Tanque), ambos fortemente eutrofizados. São apresentadas listas das espécies de algas, plantas vasculares, invertebrados bênticos e vertebrados aí encontrados

Chironomidae (Diptera: Insecta) da ilha de Santa Maria

XIV Expedição Científica do Departamento de Biologia - Santa Maria 2009.O presente trabalho surge no âmbito da Expedição Científica do Departamento de Biologia da Universidade dos Açores à ilha de Santa Maria, durante a qual foram amostrados diversos ambientes aquáticos para o estudo da sua biodiversidade. O trabalho realizado possibilitou a actualização da lista de espécies de Chironomidae para a ilha de Santa Maria, tendo sido encontrados quatro novos registos para esta ilha

Impact of a purified blueberry extract on in vitro probiotic mucin-adhesion and its effect on probiotic/intestinal pathogen systems

Several arguments have been made to substantiate the need for natural antimicrobials for the food industry. With blueberry extracts, the most compelling are both their healthy connotation and the possibility of obtaining a multipurpose solution that can be an antioxidant, colorant, and antimicrobial. From an antimicrobial perspective, as blueberry/anthocyanin-rich extracts have been associated with a capacity to inhibit harmful bacteria while causing little to no inhibition on potential probiotic microorganisms, the study of potential benefits that come from synergies between the extract and probiotics may be of particular interest. Therefore, the present work aimed to evaluate the effect of an anthocyanin-rich extract on the adhesion of five different probiotics as well as their effect on the probiotics’ capacity to compete with or block pathogen adhesion to a mucin/BSA-treated surface. The results showed that, despite some loss of probiotic adhesion, the combined presence of extract and probiotic is more effective in reducing the overall amount of adhered viable pathogen cells than the PROBIOTIC alone, regardless of the probiotic/pathogen system considered. Furthermore, in some instances, the combination of the extract with Bifidobacterium animalis Bo allowed for almost complete inhibition of pathogen adhesioninfo:eu-repo/semantics/publishedVersio

Longitudinal study in male swimmers: a hierachical modeling of energetics and biomechanical contributions for performance

The aim of this study was to assess the pooled and individual response of male swimmers over two consecutive years of training and identify the energetic and biomechanical factors that most contributed for the final performance. Nine competitive swimmers (20.0 +/- 3.54 years old; 10.1 +/- 3.41 years of training experience; 1.79 +/- 0.07 m of height; 71.34 +/- 8.78 kg of body mass; 22.35 +/- 2.02 kg.m(-2) of body mass index; 1.86 +/- 0.07 m of arm span; 116.22 +/- 4.99 s of personal record in the 200 m long course freestyle event) performed an incremental test in six occasions to obtain the velocity at 4 mmol of blood lactate (V-4) and the peak blood lactate concentrations (La-peak) as energetics, and the stroke frequency (SF), stroke length (SL), stroke index and swim efficiency as biomechanical variables. Performance was determined based on official time's lists of 200 m freestyle event. Slight non-significant improvements in performance were determined throughout the two season period. All energetic and biomechanical factors also presented slight non-significant variations with training. Swimmers demonstrated high inter-individual differences in the annual adaptations. The best performance predictors were the V-4, SF and SL. Each unit of change V4, SF and SL represented an enhancement of 0.11 s, 1.21 s and 0.36 s in performance, respectively. The results show that: (i) competitive male swimmers need at least two consecutive seasons to have slight improvements in performance, energetics and biomechanical profiles; (ii) major improvements in competition performance can be accomplished by improving the V-4, SF and SL based on the individual background

Contribuição para a caracterização das águas interiores de superfície da ilha do Pico

XII Expedição Científica do Departamento de Biologia - Pico 2005.Com o objectivo de proceder à sua caracterização hidromorfológica, físico-química e biológica visitaram-se, entre 7 e 14 de Junho de 2005, 24 lagoas situadas na ilha do Pico (Açores). Todas as lagoas foram fotografadas e geo-referenciadas. Neste relatório são apresentados os resultados relativos à hidromorfologia, aos parâmetros físico-químicos da água, bem como parte dos elementos para a caracterização biológica, nomeadamente os que se referem aos peixes e às plantas vasculares

Tailoring Ca3Co4O9 microstructure and performances using a transient liquid phase sintering additive

et al.A flexible, adaptable, economical and easily scalable processing route, allowing microstructural control, is presented. It involves classical solid state sintering method and addition of liquid promoting compound. Controlled porosity and high thermoelectric performance have been attained in CaCoO by KCO additions, drastically improving the sintering procedure. KCO behaves as transient liquid phase, providing microstructural benefits, vanishing during sintering. Electrical resistivity was improved by enhanced grains connectivity and growth. Significant increase in Seebeck coefficient at high temperatures has been produced while lattice thermal conductivity was unaffected. The best ZT value, estimated at 800°C, assuming the thermal conductivity value at 140°C, is 0.35 for 5wt.% KCO samples. These values are significantly higher than that obtained in highly-dense textured materials at the same temperature. The results suggest that this approach is very effective for preparing highly-performing CaCoO-based thermoelectric materials with relatively high porosity to control thermal conductivity.The authors wish to thank the MINECO-FEDER (MAT2013-46505-C3-1-R) and Gobierno de Aragón-Fondo Social Europeo (Research Groups T12 and T87) for financial support. This research was also partially supported by FCT, Portugal (IF/00302/2012 and PEst-C), project RECI/CTM-CER/0336/2012 co-financed by FEDER, QREN reference COMPETE: FCOMP-01-0124-FEDER-027465, and the projects financed by national funds through the FCT/MEC: UID/CTM/50025/2013, UID/CTM/50011/2013.Peer Reviewe