Este artigo, situado na área da Linguística Aplicada, analisa os sambas-enredo de 2019 das escolas de samba cariocas Vila Isabel e Mangueira. A análise está afroepistemologicamente baseada na proposta do giro decolonial, especialmente nos conceitos de colonialidade do poder, do saber e do ser, de maneira que a perspectiva afrogênica possa ser um caminho para a construção de saberes desde dentro, suleados. Os resultados classificam os sambas-enredo em categorias opostas: a eurogênica e a afrogênica, indicando que as versões das narrativas contadas podem produzir discursos de silenciamento ou visibilizar o passado histórico através da reafirmação das identidades étnico-raciais.
Actuators based on polymer blends of poly(vinylidene fluoride) (PVDF) with 40 % of different ionic liquids (IL) are prepared by solvent casting. [C2mim][Cl], [C6mim][Cl], [C10mim][Cl], [C2mim][NTf2], [C6mim][NTf2] and [C10mim][NTf2] were selected in order to evaluate the effect of anion and cation sizes in the bending properties. The microstructure, mechanical and electrical properties of the blend depend on the IL type, which in turn leads to a different bending response. In particular, the mechanical properties are independent on the IL type but the AC conductivity of the composites depend more on the anion type than on the size of the alkyl chain connected to the imidazolium based cation. Thus, the bending response of the IL/PVDF composites is correlated with the anion and cation sizes and a maximum bending response of 0.3 % is achieved for a 10 volts square signal in the IL/PVDF composite with 40 wt% content of [C2mim][NTf2]. ; The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT - Portuguese Foundation for Science and Technology under Strategic Funding UID/FIS/04650/2013, UID/Multi/04551/2013, UID/QUI/50006/2013, project PTDC/EEI-SII/5582/2014, a contract under Investigador FCT 2012 program (J.M.S.S.E.), and grants SFRH/BD/90215/2012 (JCD) and SFRH/BPD/112547/2015 (CMC). Financial support from the Basque Government Industry Department under the ELKARTEK Program is also acknowledged. The authors (R. M. and S. B. H.) would like to thank the Tunisian Ministry of Higher Education and Research for its financial support. The authors thank the support of M. S. Martins (U. Minho) for supporting the electromechanical ...
Nanocomposite membranes (NCMs) of poly(vinylidene fluoride-hexafluoropropylene), PVDF-HFP, with different yttrium carbonate and magnetite loadings, are prepared, and their dual adsorption capacity over neutral arsenite and anionic arsenate species is evaluated. The nanoparticles (NPs) and the corresponding NCMs are fully characterized in morphology, microstructure, thermal, and surface properties. The nanocomposite membranes present a micrometric porous structure with a homogeneous distribution of the active nanoparticles. Chemical, thermal, and water-contact angle characteristics of the NCMs point out that they maintain the chemical and thermal stability of the polymer while improving the wettability. Arsenic removal depends on NP loading and pH of the media. For instance, efficiencies close to 100% are achieved for arsenate species under acidic conditions, while adsorption capacity over arsenite is also incremented above 80%. Fe3O4/PVDF-HFP nanocomposite shows a dual affinity for the adsorption of As(III) and As(V) species, with the maximum adsorption capacities of 92.82 and 137.08 mg g−1, respectively. In addition, both NCMs are easily activated and reused without significant efficiency loss. Consequently, the nanocomposite membranes represent low-cost, reusable, and efficient water remediation systems suitable for the long-term removal of As(III) and As(V) under conditions mimicking real polluted surface and groundwater. ; This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Projects UID/FIS/04650/20132019 and UID/QUI/50006/2019 and project PTDC/FIS-MAC/28157/2017. H. Salazar thanks the FCT for grant SFRH/BD/122373/2016. Financial support from the Basque Government Industry and Education Departments under the ELKARTEK and PIBA (PIBA-2018-06) programs is also acknowledged.
Polymer-based piezoelectric biomaterials have already proven their relevance for tissue engineering applications. Furthermore, the morphology of the scaffolds plays also an important role in cell proliferation and differentiation. The present work reports on poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), a biocompatible, biodegradable, and piezoelectric biopolymer that has been processed in different morphologies, including films, fibers, microspheres, and 3D scaffolds. The corresponding magnetically active PHBV-based composites were also produced. The effect of the morphology on physico-chemical, thermal, magnetic, and mechanical properties of pristine and composite samples was evaluated, as well as their cytotoxicity. It was observed that the morphology does not strongly affect the properties of the pristine samples but the introduction of cobalt ferrites induces changes in the degree of crystallinity that could affect the applicability of prepared biomaterials. Young's modulus is dependent of the morphology and also increases with the addition of cobalt ferrites. Both pristine and PHBV/cobalt ferrite composite samples are not cytotoxic, indicating their suitability for tissue engineering applications. ; The authors thank the FCT (Fundação para a Ciência e Tecnologia) for financial support under the framework of strategic funding UID/FIS/04650/2013, UID/QUI/00686/2013, and UID/QUI/0686/2016; project PTDC/EEI-SII/5582/2014;andprojectPOCI-01-0145-FEDER-028237. FundsprovidedbyFCTintheframeworkof EuroNanoMed2016call,ProjectLungChekENMed/0049/2016arealsogratefullyacknowledged. D.M.C.andC.R. alsothanktheFCTforthegrantsSFRH/BPD/121526/2016andSFRH/BPD/90870/2012,respectively. Finally,the authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry Department under the ELKARTEK and HAZITEK program. ...
"Available online 11 May 2016" ; Biodegradable poly(L-lactic acid) (PLLA) and PLLA/CoFe2O4 magnetic microspheres with average sizes ranging between 0.16 -3.9 m and 0.8-2.2 m, respectively, were obtained by an oil-in-water emulsion method using poly(vinyl alcohol) (PVA) solution as the emulsifier agent. The separation of the microspheres in different size ranges was then performed by centrifugation and the colloidal stability assessed at different pH values. Neat PLLA spheres are more stable in alkaline environments when compared to magnetic microspheres, both types being stable for pHs higher than 4, resulting in a colloidal suspension. On the other hand, in acidic environments the microspheres tend to form aggregates. The neat PLLA microspheres show a degree of crystallinity of 40% whereas the composite ones are nearly amorphous (17%). Finally, the biocompatibility was assessed by cell viability studies with MC3T3-E1 pre-osteoblast cells. ; This work is funded by FCT – Fundação para a Ciência e a Tecnologia, grants SFRH/BD/82411/2011 (DMC), SFRH/ BPD/90870/2012 (CR), SFRH/BD/98616/2013 (PMM) and SFRH/ BPD/97739/2013 (PM), respectively. The authors thank support from the COST Action MP1206 ''Electrospun Nano-fibres for bio inspired composite materials and innovative industrial applications" and from the Basque Government Industry Department under the ELKARTEK Program. SLM thanks the Diputación Foral de Bizkaia for financial support under the Bizkaia Talent Programme; European Union's Seventh Framework Programme; Marie Curie Actions–People; Grant agreement no. ...
During the last few decades, the interest over chalcopyrite and related photovoltaics has been growing due the outstanding structural and electrical properties of the thin-film Cu(In,Ga)Se 2 photoabsorber. More recently, thin film deposition through solution processing has gained increasing attention from the industry, due to the potential low-cost and high-throughput production. To this end, the elimination of the selenization procedure in the synthesis of Cu(In,Ga)Se 2 nanoparticles with following dispersion into ink formulations for printing/coating deposition processes are of high relevance. However, most of the reported syntheses procedures give access to tetragonal chalcopyrite Cu(In,Ga)Se 2 nanoparticles, whereas methods to obtain other structures are scarce. Herein, we report a large-scale synthesis of high-quality Cu(In,Ga)Se 2 nanoparticles with wurtzite hexagonal structure, with sizes of 10–70 nm, wide absorption in visible to near-infrared regions, and [Cu]/[In + Ga] ≈ 0.8 and [Ga]/[Ga + In] ≈ 0.3 metal ratios. The inclusion of the synthesized NPs into a water-based ink formulation for screen printing deposition results in thin films with homogenous thickness of ≈4.5 µm, paving the way towards environmentally friendly roll-to-roll production of photovoltaic systems. ; This research was funded by the Portuguese Foundation for Science and Technology (PTDC/CTM-ENE/5387/2014, PTDC/NAN-MAT/28745/2017, UID/FIS/04650/2020, UID/QUI/ 0686/2020, PTDC/FIS-MAC/28157/2017, POCI-01-0145-FEDER-028108, SFRH/BD/121780/2016); the Basque Government Industry Department (ELKARTEK, HAZITEK); the National Science Foundation (DMR-2003783 grant); the Search-ON2: revitalization of HPC infrastructure of UMinho, (NORTE07-0162-FEDER-000086), co-funded by the North Portugal Regional Operational Programme (ON.2-O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF). The use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. ...
