2,210 research outputs found

    A web-based hydroinformatic platform for water quality modelling in a river basin

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    This paper presents a hydroinformatic platform specifically designed for a Portuguese north-western river basin (river Cávado) in order to define, simulate and analyze hydrodynamics and water quality management scenarios. The software solution was designed to be operated in a web environment, taking advantage of the integration capabilities of this software environment and the user friendliness of web interfaces

    The Influence of the Distributor Plate on the Bottom Zone of a Fluidized Bed Approaching the Transition from Bubbling to Turbulent Fluidization

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    The dynamics of the bottom zone of a narrow fluidized bed, from bubbling to turbulent regimes, was studied in a cold model of 0.1 m i.d. and 1.3 m high. Tested distributor types were perforated perspex plates, with six different perforation grids, metallic mesh and porous ceramic, with pressures drops ranging from 0.05 to 350 kPa, corresponding to superficial air velocities from 0.1 to 2.3m s-1. Group B silica ballotini, within the range 0.355-0.425 mm, were used as bed material. The experimental data consisted of pressure drop and absolute pressure fluctuating signals, together with visual observations. The bottom zone presented a dynamic condition that produced higher pressure drop values than those expected with the incipient fluidization condition, particularly for the distributor plates with a higher open area. A simple model is used to describe the axial solids distribution and the dynamics characteristics of the voids created in that zone, and an attempt is made to differentiate the bubble voidage from that of the dense phase, with a value of through flow estimated in a systematic way.http://www.sciencedirect.com/science/article/B8JGF-4RT04WJ-5/1/35ae43b23db71e43caf98b5be93bab0

    Organização dos cuidados de reabilitação nas unidades de cuidados intensivos portuguesas

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    Objective: To describe the different rehabilitation care models in practice in Portuguese adult intensive care units. Methods: A simple observational (cross-sectional) study was conducted through an online survey sent to the head nurses or individuals responsible for the 58 adult intensive care units that are part of the database of the Sociedade Portuguesa de Cuidados Intensivos. Results: We identified three models of organization of rehabilitation care: care provided by the staff of the intensive care unit (22.9%), care provided by specialized external teams (25.0%), and a mixture of the previous models, combining the two situations (52.1%). In the first model, the care was provided mainly by nurses with specialization in rehabilitation and, in the second model, the care was provided by physiotherapists. No significant differences were found between the models regarding the availability of care, in hours/day or days/week (p = 0.268 and 0.994, respectively), or results such as length of hospital stay in intensive care, ventilation time, or mortality rate in the unit (p = 0.418, 0.923, and 0.240, respectively). Conclusion: The organization of rehabilitation care in Portuguese intensive care units is unique and heterogeneous. Despite different care organization models, the availability of hours of care is similar, as are the overall results observed in patients.Objetivo: Descrever os diferentes modelos de prestação de cuidados de reabilitação em prática nas unidades de cuidados intensivos de adultos portuguesas. Métodos: Estudo observacional simples (transversal), realizado por meio de inquérito on-line enviado aos enfermeiros-chefes ou responsáveis das 58 unidades de cuidados intensivos de adultos que integram a base de dados da Sociedade Portuguesa de Cuidados Intensivos. Resultados: Foram identificados três modelos de organização dos cuidados de reabilitação: cuidados prestados pela equipe da unidade de cuidados intensivos (22,9%), cuidados prestados por equipes externas especializadas (25,0%), um misto dos modelos anteriores, conjugando as duas situações (52,1%). No primeiro modelo, os cuidados eram prestados essencialmente por enfermeiros com especialização em reabilitação e, no segundo, por fisioterapeutas. Não foram encontradas diferenças significativas entre os modelos no que diz respeito à disponibilidade de cuidados, em horas/dia ou dias/semana (p = 0,268 e 0,994 respetivamente), ou a resultados como tempo de internamento em cuidados intensivos, tempo de ventilação ou taxa de mortalidade na unidade (p = 0,418, 0.923 e 0,240 respetivamente). Conclusão: A organização dos cuidados de reabilitação nas unidades de cuidados intensivos portuguesas é singular e heterogênea. Apesar dos diferentes modelos de organização de cuidados, a disponibilidade de horas de cuidados é semelhante, bem como os resultados gerais observados nos doentes.info:eu-repo/semantics/publishedVersio

    Ferramenta de modelação desenvolvida em ambiente web para apoio à gestão de albufeiras

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    A utilização das tecnologias de informação e comunicação no caso específico da gestão de recursos hídricos, em que a incerteza associada aos processos hidrológicos determina um grau de dificuldade acrescido, revela-se essencial. Desta forma, o desenvolvimento de ferramentas que permitam a consulta de dados de redes de monitorização hidrológica, de previsões meteorológicas e de resultados de simulação em ambientes de múltiplas plataformas, fixas ou móveis, é uma das tarefas fundamentais para a incorporação das tecnologias de informação nos processos correntes de gestão de recursos hídricos. No presente trabalho apresenta-se uma ferramenta, desenvolvida para ambiente web, que permite consultar informação e operar modelos hidráulicos de simulação de barragens e respetivas albufeiras. A interface é adaptável a cada caso de estudo e poderá ser desenvolvida com diferentes tipos de software de modelação hidrológica e hidrodinâmica, considerando as necessidades estabelecidas pelo conjunto dos seus utilizadores. A partir da interface é possível estabelecer as condições de fronteira definidas para cada modelo, aplicar o modelo e visualizar os resultados de simulações dinâmicas. A aplicabilidade da ferramenta desenvolvida é demonstrada em exemplos de implementação em diversas albufeiras situadas no rio Guadiana (Empreendimento de Fins Múltiplos de Alqueva, Portugal

    Sustainable Production of Reclaimed Water by Constructed Wetlands for Combined Irrigation and Microalgae Cultivation Applications

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    Considering the increasing pressure on freshwater resources due to the constant increase in water consumption and insufficient wastewater control and treatment, recovering waste water is a path to overcoming water scarcity. The present work describes the potential of reusing treated wastewater (reclaimed water) for irrigation and production of microalgae biomass in an integrated way, through experimental evaluation of plant and microalgae growth, and creation of an application model. First, two parallel experiments were conducted to evaluate the use of reclaimed water produced by a constructed wetland filled with a mix of solid waste: the irrigation of a set of small pots filled with soil and planted with Tagetes patula L., and the cultivation of microalgae Chlorella sp.and a mixed microalgae population with predominant species of the genus Scenedesmus sp. in shaken flasks and tubular bubble column photobioreactors. Results indicated no negative effects of using the reclaimed water on the irrigated plants and in the cultivated microalgae. The growth indicators of plants irrigated with reclaimed water were not significantly different from plants irrigated with fertilized water. The growth indicators of the microalgae cultivated with reclaimed water are within the range of published data. Second, to apply the results to a case study, the seasonal variability of irrigation needs in an academic campus was used to propose a conceptual model for wastewater recovery. The simulation results of the model point to a positive combination of using reclaimed water for the irrigation of green spaces and microalgae production, supported by a water storage strategy. Water abstraction for irrigation purposes can be reduced by 89%, and 2074 kg dry weight microalgae biomass can be produced annually. Besides the need for future work to optimize the model and to add economical evaluation criteria, the model shows the potential to be applied to non-academic communities in the perspective of smarter and greener cities.The authors acknowledge the support from the Smart Cities Research Center(Ci2), from the Laboratory of Bioenergy and Applied Biotechnology (Biotec.IPT), and from the staff of the Lab.IPT. The work of Carolina Masseno, an exchange student from Universidade Federal Fluminense, Brasil, and the help of Orlando Fonseca is also acknowledged.N/Ainfo:eu-repo/semantics/publishedVersio

    Bioenergy routes for valorizing constructed wetland vegetation: An overview

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    Valorizing constructed wetlands vegetation into biofuels can be a way to contribute to mitigating the increasing energy demand, avoiding the use of arable land, freshwater, and fertilizers consumption, while simultaneously treating wastewater with eco-friendly technology. This work shortly overviews the main genera of wetland plants and the main routes of vegetal biomass conversion into biofuels including biochemical and thermochemical processes, and through a cross-search, in the Scopus database, the research intensity in bioenergy application for each genus was assessed. A total of 283 genera of wetland plants were identified and classified into five groups, from very common to very rare genera. The very common group includes 10 genera and contributes to 62% of the literature hits, while the 147 genera classified as very rare contribute to only 3% of the hits. Concerning the bioenergy applications, four genera stand out from the remaining. The plants of the genus Sorghum are the most referred to in bioenergy applications, followed by the genera Brassica, Miscanthus, and Saccharum. Miscanthus is a less common wetland plant, while the other genera are rarely applied in constructed wetlands. The relevance of bioenergy routes depends on the plants' group. For common wetland plants, the most relevant applications are biogas production, followed by bio-ethanol production, and pyrolysis processing. As a recommendation for future research works the genera with high energy potential should be evaluated as wetland vegetation, and it is recommended that the goal to recover wetland vegetation for bioenergy applications be viewed as an integral step of the design and implementation of constructed wetlands facilities.info:eu-repo/semantics/publishedVersio

    Screening of Solid Waste as Filler Material for Constructed Wetlands

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    The reuse of solid waste can contribute to reducing Earth’s resource depletion, directly through use in the original production processes or by valorisation in alternative applications. In the present work, ten solid wastes were evaluated as candidates for filling material in constructed wetlands (CWs). For that purpose, physical characterization, leaching and adsorptiontests were conducted. Limestone fragments and brick fragments resulting from construction activities, coal slags resulting from power plants, snail shells resulting from the food and catering industry, and cork granulates resulting from the cork industry have potential for use as CW fillers. These five materials have adequate physical properties and some capacity to adsorb phosphorous and organic compounds from wastewater. On the other hand, crushed eggshells resulting from egg farms, dealcoholized grape pomaces resulting from alcohol distilleries, olive seeds waste from olive-oil mills, and pine bark fragments and wood pellets resulting from forestry cleaning activities, wood mills and pulp mills did not demonstrate sufficient potential to be used as CW fillers, either because they have very low adsorption capacities or leach compounds in contact with water, or because they have less adequate physical properties. None of the tested solid wastes showed the ability to adsorb nitrogen compounds. Although the five selected materials do not present a special capability for adsorption of nitrogen, phosphorous and organic compounds, they can all be valued as CW fillers, representing a way to reduce the amount of solid waste sent to landfills.This work was supported by Program FEDER, ref. POCI-01-0145-FEDER-023314, project VALORBIO. The authors acknowledge the collaboration of the Lab.IPT staff and the assistance of students of chemical and environmental technology courses held at Instituto Politécnico de Tomar. Special thanks to Alcino Serras, Ana Alves, Isabel Silva, Joel Nunes and Nuno Graça.info:eu-repo/semantics/publishedVersio

    Plane sudden expansion flows of viscoelastic liquids

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    We report a systematic numerical investigation of the creeping flow of three different viscoelastic models, the UCM, Oldroyd-B and the linear form of the PTT model, through a 1:3 planar sudden expansion. Although the effect of elasticity is to reduce both the length and intensity of the recirculation region downstream of the expansion, we show that this reduction is much lower than previous studies have suggested and that, at high Deborah number, a significant region of recirculation still exists for all of the models studied

    Lossy-to-Lossless Compression of Biomedical Images Based on Image Decomposition

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    The use of medical imaging has increased in the last years, especially with magnetic resonance imaging (MRI) and computed tomography (CT). Microarray imaging and images that can be extracted from RNA interference (RNAi) experiments also play an important role for large-scale gene sequence and gene expression analysis, allowing the study of gene function, regulation, and interaction across a large number of genes and even across an entire genome. These types of medical image modalities produce huge amounts of data that, for several reasons, need to be stored or transmitted at the highest possible fidelity between various hospitals, medical organizations, or research units
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