478 research outputs found
Development of equipment for destruction of pesticie waste in water using nanostructured photocatalysts
Síntese e caracterização de filmes finos nanoestruturados de TiO2 : Ag e aplicação na fotodegradação de corantes.
O comportamento do aluno em um curso a distância dentro do ambiente Moodle: contrapontos entre a ótica inicial e seu uso atual.
O objetivo deste trabalho é analisar as dificuldades apresentadas pelos alunos de cursos em EaD. Para tanto, utilizou-se dados extraídos de um questionário de inscrição para um curso on-line, em que era solicitado aos alunos que listassem seus maiores problemas com os cursos que já haviam feito. Puderam ser identificadas seis categorias de problemas com: AVA, tutor, técnicos, de organização, de colaboração e de conteúdo
Development of TiO2 thin films prepared by the polymeric precursor method applied to photocatalytic degradation of rhodamine B
Determinação da composição nutricional e sais minerais de frutos de juçara (Euterpe Edulis) coletados na região de Curitiba, PR.
bitstream/item/145214/1/CT-374-Cristiane-Helm.pd
Bending Analysis of Nonlocal Functionally Graded Beams
In this paper, we study the nonlocal linear bending behavior of functionally graded beams subjected to distributed loads. A finite element formulation for an improved first-order shear deformation theory for beams with five independent variables is proposed. The formulation takes into consideration 3D constitutive equations. Eringen's nonlocal differential model is used to rewrite the nonlocal stress resultants in terms of displacements. The finite element formulation is derived by means of the principle of virtual work. High-order nodal-spectral interpolation functions were utilized to approximate the field variables, which minimizes the locking problem. Numerical results and comparisons of the present formulation with those found in the literature for typical benchmark problems involving nonlocal beams are found to be satisfactory and show the validity of the developed finite element model
Nonuniform collective dissolution of bubbles in regular pore networks
Understanding the evolution of solute concentration gradients underpins the prediction of porous media processes limited by mass transfer. Here, we present the development of a mathematical model that describes the dissolution of spherical bubbles in two-dimensional regular pore networks. The model is solved numerically for lattices with up to 169 bubbles by evaluating the role of pore network connectivity, vacant lattice sites and the initial bubble size distribution. In dense lattices, diffusive shielding prolongs the average dissolution time of the lattice, and the strength of the phenomenon depends on the network connectivity. The extension of the final dissolution time relative to the unbounded (bulk) case follows the power-law function, Bk/ℓ, where the constant ℓ is the inter-bubble spacing, B is the number of bubbles, and the exponent k depends on the network connectivity. The solute concentration field is both the consequence and a factor affecting bubble dissolution or growth. The geometry of the pore network perturbs the inward propagation of the dissolution front and can generate vacant sites within the bubble lattice. This effect is enhanced by increasing the lattice size and decreasing the network connectivity, yielding strongly nonuniform solute concentration fields. Sparse bubble lattices experience decreased collective effects, but they feature a more complex evolution, because the solute concentration field is nonuniform from the outset
Does Speaking Two Dialects in Daily Life Affect Executive Functions? An Event-Related Potential Study
Whether using two languages enhances executive functions is a matter of debate. Here, we
take a novel perspective to examine the bilingual advantage hypothesis by comparing bidialect
with mono-dialect speakers’ performance on a non-linguistic task that requires executive
control. Two groups of native Chinese speakers, one speaking only the standard Chinese
Mandarin and the other also speaking the Southern-Min dialect, which differs from the
standard Chinese Mandarin primarily in phonology, performed a classic Flanker task. Behavioural
results showed no difference between the two groups, but event-related potentials
recorded simultaneously revealed a number of differences, including an earlier P2 effect in
the bi-dialect as compared to the mono-dialect group, suggesting that the two groups
engage different underlying neural processes. Despite differences in the early ERP component,
no between-group differences in the magnitude of the Flanker effects, which is an
index of conflict resolution, were observed in the N2 component. Therefore, these findings
suggest that speaking two dialects of one language does not enhance executive functions.
Implications of the current findings for the bilingual advantage hypothesis are discussed
Influence of post and resin cement on stress distribution of maxillary central incisors restored with direct resin composite
The current study evaluated the influence of two endodontic post systems and the elastic modulus and film thickness of resin cement on stress distribution in a maxillary central incisor (MCI) restored with direct resin composite using finite element analysis (FEA). A three-dimensional model of an MCI with a coronary fracture and supporting structures was performed. A static chewing pressure of 2.16 N/mm2 was applied to two areas on the palatal surface of the composite restoration. Zirconia ceramic (ZC) and glass fiber (GF) posts were considered. The stress distribution was analyzed in the post, dentin and cement layer when ZC and GF posts were fixed to the root canals using resin cements of different elastic moduli (7.0 and 18.6 GPa) and different layer thicknesses (70 and 200 μm). The different post materials presented a significant influence on stress distribution with lesser stress concentration when using the GF post. The higher elastic modulus cement created higher stress levels within itself. The cement thicknesses did not present significant changes.34222322
Neuroscience and education: prime time to build the bridge
As neuroscience gains social traction and entices media attention, the notion that education has much to benefit from brain
research becomes increasingly popular. However, it has been argued that the fundamental bridge toward education is cognitive
psychology, not neuroscience. We discuss four specific cases in which neuroscience synergizes with other disciplines to serve
education, ranging from very general physiological aspects of human learning such as nutrition, exercise and sleep, to brain
architectures that shape the way we acquire language and reading, and neuroscience tools that increasingly allow the early
detection of cognitive deficits, especially in preverbal infants. Neuroscience methods, tools and theoretical frameworks have
broadened our understanding of the mind in a way that is highly relevant to educational practice. Although the bridge’s cement is
still fresh, we argue why it is prime time to march over it
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