3122043 documents found, page 311671 of 312205
Experimental optimization of hydraulic mini-turbines
Farrero, BernardoThe use of technologies to obtain energy from renewable sources has developed extensively over time and some of them are consolidated, such as hydroelectric power plants and wind turbines. On the other hand, there are still areas with a lot to increase and that has great potential. One of the energy sources is water. Hydroelectric is one of the main renewable generators of. However, there are still areas of tec...
Caracterização dos sedimentos produzidos por simulação de chuva sobre a banda á...
Fonseca, Felícia; Figueiredo, Tomás de; Moreira, Eduardo; Geraldes, Ana MariaA qualidade da água e o estado trófico das albufeiras são o resultado da interacção de factores intrínsecos e extrínsecos ao sistema. Entre os primeiros, salientam-se a idade e a morfologia das albufeiras. Em relação aos segundos são de realçar as características dos solos, climáticas, geológicas e morfológicas da bacia de drenagem. A ocorrência de fenómenos de erosão nas bacias de drenagem e na banda árida (zo...
Functional evaluation of patients undergoing hemodialysis with chronic kidney d...
Novo, André; Teixeira, Fernanda de Souza; Múrua, Aldo; Azevedo, José; Alves, Maria José; Paz Fernández, José António de; Travassos, FranciscoThe chronic kidney disease (CKD) is characterized by the loss of the kidney’s ability to eliminate toxic substances, concentrate urine and conserve electrolytes, with subsequent alteration of the remaining kidney function. The severe loss of kidney function is a first-order threat to life and requires the removal of toxic waste that cannot be debugged with sufficient effectiveness for other organ systems, as we...
Adsorption equilibrium and dynamics of fixed bed adsorption of CH4/N2in binderl...
Silva, José A.C.; Ferreira, Alexandre; Mendes, Patrícia A.P.; Cunha, Adelino F.; Gleichmann, Kristin; Rodrigues, AlírioThe sorption equilibrium of methane (CH4) and nitrogen (N2) in binderless beads of 5A zeolite is presented between 305 and 373 K and pressures up to 3 bar in a static electronic microbalance. The adsorbed amount of CH4 and N2 is around 1.6 and 1.02 mol/kgads, respectively, at 305 K and 3 bar. A comparison of these values with the ones in literature shows that the adsorption capacity of the 5A binderless beads i...
In vitro production of Ganoderma lucidum mycelium from northeast Portugal: The ...
Amara, KhiraThe increase in public awareness for the direct relationship between diet and health has led to concerns related to the use of commercial food additives, promoting the search for natural alternatives. Thus, natural antioxidants are among the most searched compounds nowadays, due to the issues related with the oxidative stress and its harmful effects on both food quality and human health. Tocopherols are among t...
Spread of metals through an invertebrate food chain as influenced by a plant th...
Peterson, L.R.; Trivett, V.; Baker, A.J.M.; Aguiar, Carlos; Pollard, A.J.Hyperaccumulation of metals in the shoot system of plants is uncommon, yet taxonomically and geographically widespread. It may have a variety of functions, including defense against herbivores. This study investigated the effects of hyperaccumulation on metal concentrations across trophic levels. We collected plant material, soil, and invertebrates from Portuguese serpentine outcrops whose vegetation is dominat...
DPOC. Um estudo de caso. Contributos da enfermagem de reabilitação
Diz, Elisabete; Gomes, Maria José; Galvão, Ana MariaA DPOC é uma doença progressivamente incapacitante, o que a torna um foco da Enfermagem de Reabilitação. As intervenções da enfermagem de reabilitação contribuem de forma significativa para o melhoramento da sintomatologia, contribuindo para uma maior capacidade no desempenho das suas atividades de vida, que se vai refletir na qualidade de vida destes doentes.
ADACOR: a holonic architecture for agile and adaptive manufacturing control
Leitão, Paulo; Restivo, FranciscoIn the last decades significant changes in the manufacturing environment have been noticed: moving from a local economy towards a global economy, with markets asking for products with higher quality at lower costs, highly customised and with short life cycle. In these circumstances, the challenge is to develop manufacturing control systems with intelligence capabilities, fast adaptation to the environment chang...
A real-time estimator of electrical parameters for vector controlled induction ...
Leite, V.; Araújo, Rui Esteves; Freitas, Diamantino SilvaThis paper presents an application of the extended Kalman filter (EKF) to the simultaneous on-line estimation of the dq rotor flux components and all the electrical parameters of a vector controlled induction motor. A time-discrete reduced order model structure is deduced and presents a simple and reduced state equation and a scalar output equation. This approach, combined with the use of the rotor reference fr...
Perceções dos alunos acerca das questões ambientais: análise de uma experiência...
Fernandes, Júlia Susana; Rodrigues, Maria JoséEste estudo insere-se no âmbito da dissertação de Mestrado em Ensino do 1.o Ciclo do Ensino Básico e de Matemática e Ciências Naturais no 2.o Ciclo do Ensino Básico. Neste texto pretendemos evidenciar as perceções dos alunos e os conhecimentos que têm acerca das questões ambientais.