1,654 research outputs found

    Biomimetic flow fields for proton exchange membrane fuel cells: A review of design trends

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    Bipolar Plate design is one of the most active research fields in Polymer Electrolyte Membrane Fuel Cells (PEMFCs) development. Bipolar Plates are key components for ensuring an appropriate water management within the cell, preventing flooding and enhancing the cell operation at high current densities. This work presents a literature review covering bipolar plate designs based on nature or biological structures such as fractals, leaves or lungs. Biological inspiration comes from the fact that fluid distribution systems found in plants and animals such as leaves, blood vessels, or lungs perform their functions (mostly the same functions that are required for bipolar plates) with a remarkable efficiency, after millions of years of natural evolution. Such biomimetic designs have been explored to date with success, but it is generally acknowledged that biomimetic designs have not yet achieved their full potential. Many biomimetic designs have been derived using computer simulation tools, in particular Computational Fluid Dynamics (CFD) so that the use of CFD is included in the review. A detailed review including performance benchmarking, time line evolution, challenges and proposals, as well as manufacturing issues is discussed.Ministerio de Ciencia, Innovación y Universidades ENE2017-91159-EXPMinisterio de Economía y Competitividad UNSE15-CE296

    Using Virtual Models to Evaluate Real Products For Real Bodies

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    We study the effects of self-perception on consumer creation of avatars (virtual models) for evaluating digital representations of bodyinvolving products (apparel) to be used on their real body in the real world. In our experiments, consumers used online tools to create virtual models of themselves and virtually "try on" clothing before making purchase decisions. Results show that consumer use of interactive online tools and prompting heightened awareness of their actual physical appearance significantly influences online evaluation of body-involving products. Individual differences in body esteem and preference for visual style of processing also influence consumer evaluation and use of avatars

    Caracterização do pão regional do distrito de Viseu e de Pão São

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    Dissertação de Mestrado em Qualidade e Tecnologia AlimentarO objectivo deste estudo visa a caracterização de diferentes amostras de pão Regional e pão São, procurando encontrar semelhanças e identificar os elementos diferenciadores dos mesmos. As amostras de pão Regional foram recolhidas no distrito de Viseu: Carregal do Sal, Cabanas de Viriato, Santar, Viseu, Mangualde, São Pedro do Sul e São Cipriano. No caso do pão São as amostras foram fornecidas pela empresa produtora, Fábrica do Pão localizada em Seia. Procedeu-se à caracterização física, química e sensorial, tendo sido avaliadas as diferentes propriedades em termos de média e desvio padrão das réplicas efectuadas. Posteriormente, procedeu-se a uma análise estatística, para comparação de médias e avaliação da significância das diferenças, tendo para tal sido usado o teste de Tuckey HSD. Foram ainda calculados os coeficientes de correlação de Pearson. Os resultados foram analisados recorrendo ao software SPSS para o Windows versão 19.0 e Statistic versão 6., sendo realizado o teste de análise de variância "one-way" (ANOVA). Numa fase posterior, os valores obtidos para as características do pão foram sujeitos a uma análise de componentes principais (PCA) e uma análise de Cluster. Em relação aos parâmetros químicos analisados no pão Regional, as amostras apresentaram algumas semelhanças e algumas diferenças, assim como também a nível físico e sensorial. No entanto, no que respeita à análise sensorial, as amostras foram, de modo geral, percepcionadas da mesma forma pelos provadores, não sendo detectadas diferenças significativas. Ainda assim, em termos de apreciação global a amostra preferida foi a da pastelaria Flor de Cabanas. Em relação aos parâmetros químicos, físicose sensoriais do pão São, as amostras mostraram-se semelhantes entre si, o que pode ser explicado por terem basicamente a mesma constituição em termos de ingredientes. Contudo, será de assinalar algumas diferenças em termos de fibra, hidratos de carbono, proteína e cloretos, devido à presença de farinha de tremoço numa das amostras. Quando comparadas as amostras de pão Regional com as de pão São, verificou-se que estas se apresentaram bastante diferentes, quer em termos químicos, físicos ou nível sensorial. Foi possível observar que ao nível sensorial os pães Regionais foram os preferidos pelos provadores.ABSTRACT: The aim of this study is the characterization of different samples of regional bread and healthy bread, trying to identify the similarities and contrasting elements in them. The regional bread samples were collected in the District of Viseu: Carregal do Sal, Cabanas de Viriato, Santar, Viseu, São Pedro do Sul and São Cipriano. The healthy bread samples were provided by the production company "Fábrica do Pão", located in Seia. The physical, chemical and sensory characterization was undertaken, having been avaluted the different proprerties in terms of mean value and standard deviation of the replicas made. Later, we proceeded to a statistical analysis for comparison of means and assessing the significance of the differences, having been used for this the Tukey HSD test. We also calculated the Pearson correlation coefficients. The results were analyzaed using the SPSS software version 19.0 for Windows and Statistica version 6, having been performed an analysis of variance "one way"(ANOVA). At a later stage, the values obtained for the characteristics of bread were subjected to principal components analysis (PCA) and cluster analysis. Regardind the chemical parameters analyzed in the regional bread, the samples showed some similarities and differences, as well as regarding the physical and sensory parameters. However, concerning the sensory analysis, the samples were generally perceived by the panelists in the same way, and no significant differences were observed. Still, in terms of the same way preferred by the panelists the sample from pastry "Flor de Cabanas". With respect to chemical, physical and sensory parameters of the healthy bread, the samples were similar, which can be explained by having basically the same constitution in terms of ingredients. However, there can be noted some differences in terms of fiber, carbohydrates, protein and chlorides, due to the presence of lupine flour in one sample. When comparing the regional bread samples with the healthy bread ones, it was found that they quite different, either at the chemical, physical or sensory levels. It was observed that at the sensory level the regional breads were those preferred by the tasters

    Never Deaf of Learning with Heart: Understanding the Essence of Handling Pupils with Hearing Impairment

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    This transcendental phenomenology study aimed at describing and understanding the lived experience of eight (8) Special education teachers handling learners with hearing impairment.Specifically, they were private school teachers in the cities of Biñan, Sta. Rosa and San Pedro Laguna, Philippines who were purposively selected using inclusion criteria. Framed with the approach of Moustakas (1994) as cited by Creswell (2007), the researchers carefully analyzed the participants’ verbatim accounts which resulted in six (6) themes categorized into textural and structural descriptions. Collectively taken, the essence of the study highlighted the participants’ experience in handling hearing-impaired learners which covered engaging them in different activities (Theme 1), customized communication with them (Theme 2), and love and drive to reach out to these individuals (Theme 3). They coped with the challenges they face by clinging to the vital role of assessment tools (Theme 4), highlighting values in teaching (Theme 5) and viewing their profession as a calling of commitment and devotion (Theme 6). The lived experiences of special education teachers with learners diagnosed with hearing impairment may serve as a feedback for special education instructional materials suppliers or developers in improving the contents of their works to better cater the needs of special education teachers in terms of the choice of innovated instructional materials that specifically address the learning needs of students in special education

    Isolation and characterization of endosymbiotic bacteria from copper contaminated soils in Chile

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    Legume endosymbiotic bacteria indigenous of copper (Cu)-contaminated soils from Chile have been isolated using pea (Pisum sativum), bean (Phaseolus vulgaris) and alfalfa (Medicago sativa) as trap host plants. Highly contaminated soils only produced nodules in certain legume hosts, whereas nodulation was observed in the three legume hosts when inoculated with soils containing a low Cu concentration. A collection of 362 strains was isolated, and their levels of Cu resistance were tested in media supplemented with increasing metal concentrations and in disk diffusion assays. By these two approaches, 84 strains displaying levels of Cu resistance higher than those exhibited by the corresponding reference strains were selected. The most resistant strains isolated from alfalfa and bean nodules grew normally at 3 mM and 2.5 mM CuSO4 and were obtained from two different highly contaminated soils. Strains nodulating pea plants showed similar levels of resistance to Cu (2-2.5 mM CuSO4) and were isolated from low-contaminated soils. Our data suggest a reduction of microbial diversity in agricultural Cu-contaminated soils from Chil

    Detection of a Corrugated Velocity Pattern in the Spiral Galaxy NGC 5427

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    Here we report the detection, in Halpha emission, of a radial corrugation in the velocity field of the spiral galaxy NGC 5427. The central velocity of the Halpha line displays coherent, wavy-like variations in the vicinity of the spiral arms. The spectra along three different arm segments show that the maximum amplitude of the sinusoidal line variations are displaced some 500 pc from the central part of the spiral arms. The peak blueshifted velocities appear some 500 pc upstream the arm, whereas the peak redshifted velocities are located some 500 pc downstream the arm. This kinematical behavior is similar to the one expected in a galactic bore generated by the interaction of a spiral density wave with a thick gaseous disk, as recently modeled by Martos & Cox (1998).Comment: Accepted for publication in Ap

    Numerical Modeling of physical-biological interactions in the Alboran Sea with a submesoscale-resolving model

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    Ageostrophic motion, such those associated to internal hydraulic jumps, propagating nonlinear internal waves, and submesoscale vortices, are recognized to efficiently supply nutrients to the euphotic zone and thereby fuel biological productivity. These processes are ubiquitous in the Strait of Gibraltar and the adjacent Alboran Sea, and therefore are expected to play an important role in the overall biomass budget of the basin. This has been investigated with a three-dimensional, tidally-forced, high-resolution model [O(1km)] ocean model embedded with an ecosystem NPZD module. We found that tidal mixing in the Strait of Gibraltar enhances remarkably local primary production and drive a net flow of biomass to the Alboran Sea. Additionally, tides also cause an inflow of nutrients confined to the photic layer, which increase further the Alboran Sea biomass through the enhancement of local primary productivity. Subinertial accelerations of the Atlantic flow are also found to temporary enhance biological productivity through the advection of shear vorticity (and submesoscale eddies) from the Strait to the Alboran Sea.JRC.H.1-Water Resource

    The nuclear receptor LXRα controls the functional specialization of splenic macrophages.

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    Macrophages are professional phagocytic cells that orchestrate innate immune responses and have considerable phenotypic diversity at different anatomical locations. However, the mechanisms that control the heterogeneity of tissue macrophages are not well characterized. Here we found that the nuclear receptor LXRα was essential for the differentiation of macrophages in the marginal zone (MZ) of the spleen. LXR-deficient mice were defective in the generation of MZ and metallophilic macrophages, which resulted in abnormal responses to blood-borne antigens. Myeloid-specific expression of LXRα or adoptive transfer of wild-type monocytes restored the MZ microenvironment in LXRα-deficient mice. Our results demonstrate that signaling via LXRα in myeloid cells is crucial for the generation of splenic MZ macrophages and identify an unprecedented role for a nuclear receptor in the generation of specialized macrophage subsets
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