1,919 research outputs found

    Purifying Hydrogen with Inorganic Silica Membranes at High Temperatures

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    Development of high quality membranes for industrial applications will lead to cost reductions over traditional separations processes. Silica membranes are a new technology for hydrogen separation that needs R&D specifically to apply them to industrial scales. Past work has shown a carbonised template silica membrane which offered hydrostability. This resulted in better stability under steam and high temperature conditions without compromising the permselectivity for small molecules. In this paper a hydrostable silica membrane was developed for hydrogen separation having a pore cut-off around 3 Angstron units. The carbon templates did not compromise the membrane's ability to permeate hydrogen selectively rather than other major gases in a synthesised coal gasifier mixture of CO, CO2 and N2. The selectivity of H2 to N2 was 26, whilst the hydrostable property of the carbonised template membrane was maintained. Computational fluid dynamics (CFD) can be used to develop membrane systems in tandem with these intrinsic improvements. CFD simulation studies were also conducted to gain better insight into the macroscopic flow parameters

    Optical Coherence Tomography Angiography Vessel Density in Healthy, Glaucoma Suspect, and Glaucoma Eyes.

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    PurposeThe purpose of this study was to compare retinal nerve fiber layer (RNFL) thickness and optical coherence tomography angiography (OCT-A) retinal vasculature measurements in healthy, glaucoma suspect, and glaucoma patients.MethodsTwo hundred sixty-one eyes of 164 healthy, glaucoma suspect, and open-angle glaucoma (OAG) participants from the Diagnostic Innovations in Glaucoma Study with good quality OCT-A images were included. Retinal vasculature information was summarized as a vessel density map and as vessel density (%), which is the proportion of flowing vessel area over the total area evaluated. Two vessel density measurements extracted from the RNFL were analyzed: (1) circumpapillary vessel density (cpVD) measured in a 750-μm-wide elliptical annulus around the disc and (2) whole image vessel density (wiVD) measured over the entire image. Areas under the receiver operating characteristic curves (AUROC) were used to evaluate diagnostic accuracy.ResultsAge-adjusted mean vessel density was significantly lower in OAG eyes compared with glaucoma suspects and healthy eyes. (cpVD: 55.1 ± 7%, 60.3 ± 5%, and 64.2 ± 3%, respectively; P < 0.001; and wiVD: 46.2 ± 6%, 51.3 ± 5%, and 56.6 ± 3%, respectively; P < 0.001). For differentiating between glaucoma and healthy eyes, the age-adjusted AUROC was highest for wiVD (0.94), followed by RNFL thickness (0.92) and cpVD (0.83). The AUROCs for differentiating between healthy and glaucoma suspect eyes were highest for wiVD (0.70), followed by cpVD (0.65) and RNFL thickness (0.65).ConclusionsOptical coherence tomography angiography vessel density had similar diagnostic accuracy to RNFL thickness measurements for differentiating between healthy and glaucoma eyes. These results suggest that OCT-A measurements reflect damage to tissues relevant to the pathophysiology of OAG

    A dark scenario for Cerrado plant species: effects of future climate, land-use, and protected areas ineffectiveness

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    Aim: The anthropogenic climate change and land-use change are considered two of the main factors that are altering biodiversity at the global scale. An evaluation that combined both factors can be relevant to detect which species could be the most vulnerable and reveal the regions of highest stability or susceptibility to biodiversity.We aimed to (i) assess the effect of the climate change and land-use on the distribution of the Cerrado plant species for different countries where it occurs, (ii) evaluate the efficiency of the current protected areas (PAs) network to safeguards species under different greenhouse gas (GHG) emissions and land-use and (iii) estimate the vulnerability of species caused by protection efficiency and habitat loss.Location: Bolivia, Brazil, and ParaguayMethods: We modeled the distribution of 1,553 plant species of Cerrado and evaluated species range loss caused by present and future land-use and two GHG for 2050 and 2080. We assessed the species vulnerability combining the representativeness of a species´ distribution within conservation units and the loss of species range outside PAs.Results: We found that climate change and land-use will cause great damage to Cerrado flora by 2050 and 2080, even under optimistic conditions. Unfortunately, the greatest intensity and extent of land-use will have to overcome on the regions where the greatest richness will be harbored. The conservation of the species will be seriously affected since the PAs network is not as efficient in safeguarding them under current or future conditions. Main conclusions: The low level of protection together with the losses caused by the advance of the agricultural frontier will lead to most species being highly vulnerable. Due to the climate and land-use, effects showed different interactions in each country, conservation strategies should be implemented at transboundary and national levels.Fil: Velazco, Santiago José Elías. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Universidade Federal do Paraná; BrasilFil: Villalobos, Fabricio. Instituto de Ecología; México. Universidade Federal de Goiás; BrasilFil: Galvao, Franklin. Universidade Federal do Paraná; BrasilFil: de Marco Junior, Paulo. Universidade Federal de Goiás; Brasi

    Alterações microbianas e químicas de um gleissolo sob macaubeiras nativas em função da variação sazonal e espacial.

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    RESUMO: A macaúba (Acrocomia aculeata) é uma alternativa para a produção de biodiesel e, consorciada com pastagem, pode auxiliar na recuperação de áreas degradadas. O objetivo deste trabalho foi estudar as alterações nos atributos microbiológicos, na matéria orgânica e no N total do solo, em função da variação sazonal e espacial em um Gleissolo sob maciço de macaubeiras nativas, no Cerrado. O estudo observacional foi realizado na região de Planaltina de Goiás, na Fazenda Agropecuária Santa Fé. Foram selecionadas dez árvores em uma mata com macaubeiras nativas no bioma cerrado. A coleta de solo foi realizada na camada de 0 a 10 centímetros de profundidade, sob uma linha horizontal, imaginária, traçada a partir da base do caule das macaubeiras. As amostras de solo foram coletadas a 50, 150 e 250 centímetros de distância do caule da palmeira, durante o verão chuvoso (março de 2010) e inverno seco (julho 2010). Para a avaliação estatística das variáveis observadas, utilizou-se um modelo misto. As médias das variáveis observadas foram submetidas a testes para verificar se seguiam a distribuição normal, e a homogeneidade de variâncias. Em seguida, os dados foram submetidos ao teste F e as médias foram comparadas pelo teste t. Os atributos carbono microbiano (Cmic), respiração basal (RB), quociente metabólico (qCO2), a matéria orgânica do solo (MOS) e a relação C/N do solo são sensíveis à variação sazonal e espacial em mata de macaubeiras no Cerrado. O nitrogênio total (NT) foi sensível à variação espacial. A microbiota presente no solo sob macaubal se manteve mais equilibrada durante o período seco, apresentando maiores teores de carbono microbiano e quociente microbiano e menor quociente metabólico e relação C/N do solo

    ENERGY STUDY OF A HEAT PUMP USED FOR AIR ( HEATING AND DEHUMIDIFICATION

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    Heat pump assisted dryers can realize considerable savings of primary energy as compared with conventionally-heated air drying. This manuscript analyzes the design and construction aspects of a heat pump assisted dryer for biological products. The performance of the heat pump is investigated through an energy analysis, carried out under operating conditions of practical interest. The system is operated using R22 and is also evaluated with respect to the coefficient of performance (COP). Although the current trend is to invest in low-energy, low-carbon technologies, heat pump assisted dryers remain underexplored in the industrial sector due to its more complex operation

    Comparative study between wet and dry etching of silicon for microchannels fabrication

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOIn this work we present a comparative study of two processes for the fabrication of an array of microchannels for microfluidics applications, based on integrated-circuit technology process steps, such as lithography and dry etching. Two different methods were investigated in order to study the resulting microstructures: wet and dry deep etching of silicon substrate. The typical etching depth necessary to the target application is 50 mu m.1093015FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2016/09509-112. Conference on Advanced Fabrication Technologies for Micro/Nano Optics and Photonics3 a 5 de Fevereiro de 2019San Francisco, CA, Estados UnidosSPIE; Nanoscribe Gmb
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