Analise semiotica de um ava (ambiente virtual de ensino aprendizagem) : características cts através da escada semotica de Stamper

Este artigo demonstra um estudo e aplicação da análise semiótica, para a avaliação de interfaces de ambientes virtuais de ensino-aprendizagem (AVA), de acordo com a escada semiótica de Stamper. Com base nas características CTS (Ciência,Tecnologia e Sociedade) encontrada nas camadas “degrais” da escada. Em específico, usamos a metodologia para qualidade de interfaces definida por Schimiguel, que instancia critérios de qualidade para cada uma das camadas da escada semiótica de Stamper. Com base nos resultados dessa investigação foi possível sugerir algumas recomendações nas seis camadas analisadas, sinalizando ainda para cada uma dessas recomendações um enfoque CTS, uma descrição que tem como propósito facilitar a implementação e otimização de AVAS

Scattering hypervolume for ultracold bosons from weak to strong interactions

The elastic scattering properties of three bosons at low energy enter the many-body description of ultracold Bose gases via the three-body scattering hypervolume $D$. We study this quantity for identical bosons that interact via a pairwise finite-range potential. Our calculations cover the regime from strongly repulsive potentials towards attractive potentials supporting multiple two-body bound states and are consistent with the few existing predictions for $D$. We present the first numerical confirmation of the universal predictions for $D$ in the strongly interacting regime, where Efimov physics dominates, for a local nonzero-range potential. Our findings highlight how $D$ is influenced by three-body quasibound states with strong $d$-wave or $g$-wave characteristics in the weakly interacting regime.Comment: 13 pages, 8 figure

Experimental and numerical investigations of fracture behavior of magnetostrictive materials

Abstract: The purpose of this work is the characterization of the fracture behaviour of giant magnetostrictive materials subjected to a magnetic field. Both experimental and numerical investigations have been performed, focusing on iron and rare earth alloys, such as the commercially named Terfenol-D. Tests have been carried out on single-edge precracked specimens subjected to three-point bending in the presence of magnetic fields of various intensities and fracture loads have been measured at different loading rates. Recent studies on local stress fields in proximity of crack and notch tips have shown that Strain Energy Density (SED), averaged in a circular control volume which includes a crack tip, could be a robust parameter in the assessment of brittle fracture resistance of several materials. Coupled-field analyses have then been performed on both plane stress and plane strain finite element models and the effect of the magnetic field on fracture resistance of Terfenol-D alloy was predicted in terms of averaged SED. A relationship between the SED's control volume size and the loading rate has also been proposed

Challenges in using ionic liquids for cellulosic ethanol production

The growing need to expand the use of renewable energy sources in a sustainable manner, providing greater energy supply security and reducing the environmental impacts associated with fossil fuels, finds in the agricultural by-product bioethanol an economically viable alternative with significant expansion potential. In this regard, a dramatic boost in the efficiency of processes already in place is required, reducing costs, industrial waste, and our carbon footprint. Biofuels are one of the most promising alternatives to massively produce energy sustainably in a short-term period. Lignocellulosic biomass (LCB) is highly recalcitrant, and an effective pretreatment strategy should also minimize carbohydrate degradation by diminishing enzyme inhibitors and other products that are toxic to fermenting microorganisms. Ionic liquids (ILs) have been playing an important role in achieving cleaner processes as a result of their excellent physicochemical properties and outstanding performance in the dissolution and fractionation of lignocellulose. This review provides an analysis of recent advances in the production process of biofuels from LCB using ILs as pretreatment and highlighting techniques for optimizing and reducing process costs that should help to develop robust LCB conversion processes.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit, and CEECIND/03378/2018; by LABBELS—Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020 and H.R. acknowledges Xunta de Galicia for support through project ED431B 2020/021, co-funded by the European Regional Development Fund, and “Agrupación Europea de Cooperación Territorial—Galicia—Norte de Portugal (GNP-AECT)” for support of a visiting stay at the University of Minho via Iacobus program.info:eu-repo/semantics/publishedVersio

ESR spectra of PF_2 and SF_3 radicals

[No abstract

P. FARNÉS SCHERER, Construir y adaptar las Iglesias. Orientaciones y sugerencias prácticas sobre el espacio celebrativo, según el espíritu del Concilio Vaticano II, Ed. Regina, Barcelona 1989, 272 pp., 13 x 19,5. [RECENSIÓN]

We study the growth of two- and three-body correlations in an ultracold Bose gas quenched to unitarity. This is encoded in the dynamics of the two- and three-body contacts analyzed in this work. Via a set of relations connecting many-body correlations dynamics with few-body models, signatures of the Efimov effect are mapped out as a function of evolution time at unitarity over a range of atomic densities $n$. For the thermal resonantly interacting Bose gas, we find that atom-bunching leads to an enhanced growth of few-body correlations. These atom-bunching effects also highlight the interplay between few-body correlations that occurs before genuine many-body effects enter on Fermi timescales

Analise semiotica de um ava (ambiente virtual de ensino aprendizagem) : características cts através da escada semotica de Stamper

Este artigo demonstra um estudo e aplicação da análise semiótica, para a avaliação de interfaces de ambientes virtuais de ensino-aprendizagem (AVA), de acordo com a escada semiótica de Stamper. Com base nas características CTS (Ciência,Tecnologia e Sociedade) encontrada nas camadas "degrais" da escada. Em específico, usamos a metodologia para qualidade de interfaces definida por Schimiguel, que instancia critérios de qualidade para cada uma das camadas da escada semiótica de Stamper. Com base nos resultados dessa investigação foi possível sugerir algumas recomendações nas seis camadas analisadas, sinalizando ainda para cada uma dessas recomendações um enfoque CTS, uma descrição que tem como propósito facilitar a implementação e otimização de AVAS