84 research outputs found

    Gas-liquid flow dispersion in a vertical pipe

    Get PDF
    The main purpose of this work was to analyse the transport f a solute dissolved in a flowing liquid in upward direction at low velocity along a vertical column, in the bottom of which slugs are injected. These experiments were carried out in a column with an internal diameter of 19 mm and height of 344.2 cm. Liquid flowrates of 1.0, 2.5 and 5.5 cm3/s were utilized, and an enlarged variety of gas flowrates were injected; in these conditions the slugs were normally formed at a frequency between 0.78 and 88.1 s-1. The scientific techniques used in this study based on the measurement, at the top of the column, of a tracer solution injected in its bottom. A simplified physical model was developed to explain the results obtained, which was based on two hypotheses: (i) the flow of the liquid between two slugs is laminar, being the respective profile of velocity approximate to the Poiseuille law; (ii) the stirring action provoked by each slug in the liquid is limited to a small region, the wake of slug, which can be taken as a “perfectly mixed tank”. One of the most relevant conclusions derived from this work and which at first analysis would appear paradoxical, is that, it is possible to proceed in such a way that the bubbling of gas through a liquid will provoke less dispersion in the residence time of liquid than which would be obtained in the absence of the introduction of gas

    Oxigenação de águas em colunas de borbulhamento inclinadas com um sistema de anteparos perfurados

    Get PDF
    Apresenta-se um estudo teórico e experimental sobre transferência de oxigénio para água em colunas de borbulhamento inclinadas. Para permitir a absorção, instalou-se ao longo da coluna um sistema de anteparos perfurados igualmente espaçados. A inclinação variou entre 0º (vertical) e 60º. Desenvolve-se um modelo simples de transferência de massa considerando a coluna como uma série de “tanques” perfeitamente agitados e uma metodologia de análise que permite prever o perfil de concentrações numa coluna com qualquer número de anteparos, a partir dos valores de KLA (coeficiente de transferência de massa vezes a área interfacial) obtidos numa coluna idêntica com reduzido número de anteparos

    Mass transfer models for oxygen-water co-current flow in vertical bubble columns

    Get PDF
    The present work reports a theoretical and experimental study of mass transfer for oxygen-water co-current flow in vertical bubble columns. The axial dispersion of liquid phase was also studied. Experiments were carried out in a 32 mm internal diameter and 5.35 and 5.37 m height columns. The superficial liquid velocity ranged from 0.3 to 0.8 m/s and volumetric flow rate ratio of gas to liquid ranged from 0.015 to 0.25. Mathematical models were developed to predict concentration of gas dissolved in the liquid as function of different physical and dynamic variables for two-phase cocurrent downflow and upflow. We obtained for the ratio of the liquid side mass transfer coefficient to initial bubbles radius, kL/r0=0.12 s-1

    Organic residue, limestone, gypsum, and phosphorus adsorption by lowland soils

    Get PDF
    Organic residue application is a low cost alternative to reduce the use of inorganic fertilizers and correctives. In order to study the effect of organic residues, limestone and gypsum application on phosphorus adsorption by lowland soils, four experiments were carried out. A Mesic Organosol (OY), a Melanic Gleysol (MG), a Haplic Gleysol (GX), and a Fluvic Neosol (RU) were used in a completely randomized design and factorial scheme (3 x 2), with five replicates: three soil amendment practices (limestone, gypsum and no corrective) and two levels of organic residue (with and without corral manure). Soil samples were incubated for 60 days, with and without organic residue incorporation. After this period, we applied the corrective and incubated the soil for 30 days, then P and basic fertilization (macro and micronutrients) were applied and the soil was incubated for additional 60 days. Equilibrium phosphorus, maximum phosphate adsorption capacity, pH, exchangeable Al and phosphorus-buffering index were measured. Organic residue and limestone application increased soil pH and reduced exchangeable Al, decreasing P adsorption. Gypsum application did not increase the pH but reduced exchangeable Al and P adsorption.A aplicação de resíduo orgânico é uma alternativa de baixo custo para reduzir a aplicação de fertilizantes inorgânicos e corretivos. Com objetivo de estudar a relação da aplicação de resíduo orgânico, calcário e gesso com adsorção de fósforo em solos de várzea conduziram-se simultaneamente quatro experimentos com os solos Organossolo Mésico (OY), Gleissolo Melânico (GM), Gleissolo Háplico (GX) e Neossolo Flúvico (RU). O delineamento experimental utilizado foi o inteiramente casualizado, em esquema fatorial 3x2, com cinco repetições, sendo três práticas de correção do solo (calcário, gesso e sem corretivo) e dois níveis de resíduo orgânico com e sem esterco de curral curtido. Amostras dos solos foram incubadas por 60 dias com e sem incorporação do resíduo orgânico; após este período, por mais 30 dias com os corretivos e em seguida por 60 dias com o fósforo e uma adubação básica com macro e micronutrientes. Determinaram-se o fósforo remanescente, capacidade máxima de adsorção de fósforo, pH, Al trocável e índice tampão de fósforo. A aplicação de resíduo orgânico, calcário - pela elevação do pH e redução dos teores de Al trocável - e gesso - pela redução de Al trocável - reduzem a adsorção de fósforo nos solos de várzea estudados

    Avaliação de políticas urbanas : o caso do município de Vila Flor

    Get PDF
    Dissertação de Mestrado em Engenharia Civil - Área de Especialização em Engenharia MunicipalO diagnóstico transversal das políticas nos sectores socio-económicos e ambientais, é uma ferramenta útil para os representantes locais fundamentarem e justificarem as decisões a implementar. Este facto levanta a questão da avaliação das políticas urbanas resultantes da aplicação dos recursos económicos e da forma de actuação. Esta temática, associada aos indicadores estatísticos preocupantes do Município de Vila Flor, justificou a investigação que consiste em diagnosticar os problemas, analisar sectores disciplinares diferentes, nomeadamente acessibilidades, estrutura demográfica, estrutura económica e o edificado, procurando determinar medidas para contrariar os índices negativos, valorizando as potencialidades e oportunidades concelhias. Para simplificação das áreas de estudo, a análise específica recai em cinco centros urbanos detectados como representativos da realidade concelhia. Interessa descrever as causas, e as políticas a implementar podendo os resultados obtidos na dissertação ser um elemento de consulta, e um contributo útil no apoio das decisões para a melhoria das políticas futuras a adoptar, criando um ciclo de planeamento integrado, passível de desenvolvimento sustentável nesta região desfavorecida. A ideia fundamental desta análise assenta no pressuposto de liderança estratégica do poder autárquico, que influencia a evolução socio-económica, impulsiona o sector privado e mobiliza a comunidade local. As iniciativas e projectos locais, num pensamento global, não se devem limitar a uma reacção perante a crise, mas devem funcionar num processo cíclico que envolva uma dinâmica de desenvolvimento, cativando recursos exógenos e activando os endógenos, em benefício da autarquia, sem descurar questões ambientais.The cross diagnosis of the policies adopted in the socio-economical and environmental sectors is a useful tool for the local representatives to back up and justify the decisions to be implemented. This fact raises the question of the evaluation of the urban policies resulting from the application of the economical resources and of the way of acting. This issue, connected with the worrying statistical indicators of the Municipality of Vila Flor, justified the research that consists of diagnosing the problems, analyzing different disciplinary sectors, namely accessibility, demographic and economical structure and edifications, trying to determine measures to change the negative rates, valuing the municipal potentialities and opportunities. In order to simplify the study areas, the specific analysis comprises five urban centres identified as representative of the municipal reality. This study describes the causes and the policies to be applied and its results can be a reference and a useful contribution to decision taking towards the improvement of future policies, opening a cycle of integrated planning, susceptible of a sustainable development in this less-favoured region. The fundamental idea of this analysis lies on the assumption of a strategic leadership by the autarchic power, which shapes the socio-economical evolution, impels the private sector and mobilises the local community. The local initiatives and projects, on a global thought, should not be limited to a reaction against crisis, but should be carried out in a cyclic process that involves a development dynamic, attracting the exogenous resources and activating the endogenous ones, in benefit of the municipality, without ignoring the environmental issues

    A importância das ações de bola parada no contexto do alto rendimento - Estudo de caso do Moreirense Futebol Clube na época 2015/2016

    Get PDF
    O presente estudo pretende indagar a importância das ações de bola parada no jogo de futebol em alto rendimento, com o objetivo de aprofundar os conhecimentos desse momento do jogo. Nesse sentido, foi realizado um estágio profissionalizante na equipa sénior do Moreirense Futebol Clube durante a época desportiva 2015/2016, com o propósito de analisar a relevância das ações de bola parada nessecontexto, tanto ao nível da operacionalização desse momento em treino, como a sua repercussão em jogo. O treino das ações de bola parada foi maioritariamente inserido no penúltimo dia do microciclo semanal, tendo como preocupações fundamentais procurar simular a realidade do jogo, em que a estratégia se torna decisiva para surpreender o adversário. Do total de jogos realizados em todas as competições, verificou-se que dos 111 golos ocorridos, entre marcados e sofridos, 49 foram provenientes, direta ou indiretamente, de ações de bola parada, o que corresponde a 44% do total dos mesmos, tendo sido o momento de jogo em que foram concretizados mais golos. De referir que desses 49 golos, marcados e sofridos, de ações de bola parada, 17 foram procedentes de segundas bolas, o que revela a pertinência desta situação, a qual deve ser tida em conta em treino, de modo a ser correspondida em jogo. Um outro aspeto interessante de averiguar foi o facto de: dos 36 pontos conquistados pelo Moreirense Futebol Clube na Primeira Liga 2015/2016, 8 foram somados pela influência direta de golos marcados através de lances de bola parada, os quais evitou a descida de divisão, assim como 13 não foram adicionados pela influência direta de golos sofridos do mesmo tipo de lances, o que permitiria classificar a equipa na sétima posição, a um ponto da qualificação para as provas europeias.The present study aims to understand the importance of the set plays in the high performance soccer match, with the purpose to explore the knowledge of this moment of the game.In this sense, a professional internship was realized in the professional team of Moreirense Futebol Clube during the season 2015/2016, with the purpose to analyze the set plays relevance in this context, both at the level ofoperationalization of this, as their repercussion in game.The set plays training was mostly introduced in the penult session of the microcycle, having as key concerns to simulate the match reality, where the strategy becomes crucial to surprise the opponent. Of the total game realized in all competitions, we have observed that of the 111 goals occurring, between scored and suffered, 49 were descendant, direct or indirectly, from set plays, that means 44% of the total of the same, sothis moment was which were achieved more goals. Also, to report that of the 49 goals, scored and suffered, of set plays, 17 were derived of second balls, which demonstrated the pertinence of this situation, which should be taken into account in training, in order to be matched during the game. Another interesting view to investigate was that: of the 36 conquered points by Moreirense Futebol Clube in the First League 2015/2016, 8 were achieved by direct influence of scored goals through set plays, which avert the descent of division, as well as 13 weren't added by direct influence of suffered goals of the same shot type, what would classify the team in the seventh position, to a point of qualification for the European competition

    Níveis críticos e disponibilidade de fósforo em solos cultivados com arroz inundado

    Get PDF
    Os solos de várzea apresentam-se com um grande potencial para o cultivo do arroz irrigado por inundação. No presente trabalho, objetivou-se estimar os níveis críticos de P pelos extratores Mehlich 1 e resina em solos de várzea cultivados com arroz sob inundação e identificar as frações de P que estão contribuindo para a nutrição fosfatada do arroz. Foram utilizados quatro solos de várzea pré-cultivados com feijoeiro: Glei Pouco Húmico (GP), Aluvial (A), Glei Húmico (GH) e Orgânico (O). O experimento foi em delineamento inteiramente casualizado, em fatorial 4 x 5 x 2 com três repetições, sendo: quatro solos, cinco doses de P (75, 150, 300, 500 e 800 mg dm-3) e dois níveis de calagem: ausência e presença. Após 60 dias de inundação, coletaram-se amostras dos solos para a determinação do P por Mehlich 1 e resina e fracionamento de P. Cada parcela constituiu de um vaso de 3 dm³ em que cultivaram-se duas plantas. As formas de P lábeis e pouco lábeis dos solos contribuíram para a nutrição fosfatada do arroz. Os dois extratores demonstraram eficiência na avaliação do P disponível para o arroz.Lowland soils present a great potential for the flooded rice crop. This work aimed to estimate critical levels of P in waterlogged soils cultivated with rice using Mehlich 1 and anion exchange resin as soil-P extractors, compare the performance of these extractors as for the evaluation of the P availability, and study the soil-P fractions involved in the P nutrition of the rice crop. Studied soils consisted of four Histosols: Low Humic Gley (GP), Aluvial (A), Humic Gley (GH) and Bog Soil (O) which were previously cultivated with beans. The experimental design was completely randomized, in a factorial scheme, using four soils, five P rates (75, 150, 300, 500 and 800 mg dm-3) and two liming treatments (with and without liming), with three replicates. After 60 days of flooding, soil samples were submitted to P extraction by Mehlich 1 and resin, and phosphorous fractionation. Two rice plants were cultivated in pots containing 3 dm³ of waterlogged soils. The labile P and the moderately labile P of the soils contributed for rice nutrition. The two tested extractors presented efficiency in the evaluation of P availability for the rice cultivated in lowland waterlogged soils

    The role of GSTA2 polymorphisms and haplotypes in breast cancer susceptibility: A case-control study in the Portuguese population

    Get PDF
    We wish to thank Luisa Manso Oliveira, Lylliane Luz, Silvia Morgado Amaro and Maria Catarina Soveral for technical support. Center for Research in Human Molecular Genetics (CIGMH), Projects POCTI/QUI/57110/2004 from Fundacao da Ciencia e Tecnologia (FCT) and Fundacao Calouste Gulbenkian (Grant 69405) support our current research. The PhD grant SFRH/BD/17828/2004 from FCT is also acknowledged.Glutathione-S-transferases (GSTs) are a superfamily of phase II metabolizing enzymes that catalyse the detoxification of a large range of endogenous and exogenous toxic compounds, playing an important role in protecting cells against damage, through glutathione conjugation with electrophilic substances. Polymorphic variation in these enzymes that affect its activity seems to be related to individual susceptibility to various human diseases, including cancer. Of the GST super-family, the alpha class GSTs have commonly been described as one of the most versatile class, since it is responsible for detoxification of compounds such as bilirubin, bile acids and penicillin, thyroid and steroid hormones, allowing its solubilization and storage in the liver. Among the alpha class, GSTA1 and GSTA2 isoforms are the most widely expressed in human tissues. Additionally, these enzymes can catalyse conjugation of the nitrogen mustard group of alkylating anticancer drugs, some heterocyclic amines and alpha,beta-unsaturated aldehydes. Since some risk factors for increased breast cancer risk could be related to high production of reactive oxygen species during the metabolism of estrogens by catechol estrogens, or to the exposure to genotoxic compounds, and some of these toxic compounds are usually metabolized by GSTA2, we carried out a hospital based case-control study in a Caucasian Portuguese population (291 breast cancer patients without familiar history of breast cancer and 547 controls matched for age, sex and ethnicity) in order to evaluate the potential modifying role of three non-synonymous polymorphisms in the GSTA2 gene (P110S Ex 5+56C>T;, rs2234951; S112T Ex5+63G>C, rs2180314 and E210A Ex7+83A>C, rs6577) on the individual susceptibility to breast cancer. Our data show that the Studied polymorphisms are in strong linkage disequilibrium, but no association was observed between individual GSTA2 polymorphisms and haplotypes and individual susceptibility to breast cancer.publishersversionpublishe

    Utilização de ultrassom na produção de pasta de azeitona

    Get PDF
    Os produtos derivados da azeitona como o azeite e azeitonas fermentadas (Fig. 1) são muito apreciados. A necessidade de utilizar as azeitonas que não possuam aparência deseja, mas igualmente adequada ao consumo, surgiu a pasta de azeitona (Fig. 2). A pasta de azeitona é obtida do corte fino da azeitona de mesa. As tecnologias de processamento de alimentos estão em constante evolução, visando atender os anseios dos consumidores e elevar os padrões de qualidade. O ultrassom (US) surge como uma dessas novas tecnologias, considerada limpa e que pode ser aplicada a alimentos. Estudos utilizando US demonstram que sua aplicação é eficiente em processos de homogeneização, elimina microrganismos, inativa enzimas e aumenta eficiência nos processos de extração. Logo se espera que o US substitua o processo de homogeneização e tratamento térmico na fabricação da pasta de azeitona, simplificando o processo de fabricação.info:eu-repo/semantics/publishedVersio

    Chronic benign neutropenia of childhood

    Get PDF
    The term neutropenia concerns the reduction of the amount of circulating neutrophils in peripheric blood. The Chronic Benign Neutropenia of Childhood (CBNC) is characterized by the presence of a circulating neutrophils total number (absolute count) below 1,5 x 10(9)L, for over a six-month period. The diagnosis is established when the laboratorial changes occur during the first two years of life, without previous history of serious infections, nor neutrophils morphological changes, nor hypocellular bone marrow examination. The cellularity is normal or increased and a neutrophil maturation arrest at some phase can be observed. Generally, the whole process is solved by the age of four. Because this is a very rare clinical situation, it justifies a bibliographic revision about the theme. We present the clinical case of a 15 month-old-child, admitted with fever and diarrhea associated with neutropenia. Bone marrow aspiration, other laboratorial exams carried out during hospital internment and presented clinical evolution were consistent with CBNC diagnosis.publishersversionpublishe
    corecore