Durability indicators comparison for SCC and CC in tropical coastal environments

Self-compacting concrete (SCC) demands more studies of durability at higher temperatures when subjected to more aggressive environments in comparison to the conventional vibrated concrete (CC). This work aims at presenting results of durability indicators of SCC and CC, having the same water/binder relations and constituents. The applied methodologies were electrical resistivity, diffusion of chloride ions and accelerated carbonation experiments, among others, such as microstructure study, scanning electron microscope and microtomography experiments. The tests were performed in a research laboratory and at a construction site of the Pernambuco Arena. The obtained results shows that the SCC presents an average electrical resistivity 11.4% higher than CC; the average chloride ions diffusion was 63.3% of the CC; the average accelerated carbonation penetration was 45.8% of the CC; and the average open porosity was 55.6% of the CC. As the results demonstrated, the SCC can be more durable than CC, which contributes to elucidate the aspects related to its durability and consequent prolonged life cycle.

Tailored magnetic and magnetoelectric responses of polymer-based composites

The manipulation of electric ordering with applied magnetic fields has been realized on magnetoelectric (ME) materials, however, their ME switching is often accompanied by significant hysteresis and coercivity that represents, for some applications, a severe weakness. To overcome this obstacle, this work focus on the development of a new type of ME polymer nanocomposites that exhibits tailored ME response at room temperature. The multiferroic nanocomposites are based on three different ferrite nanoparticles, Zn0.2Mn0.8Fe2O4 (ZMFO), CoFe2O4 (CFO) and Fe3O4 (FO), dispersed in a piezoelectric co-polymer poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE), matrix. No substantial differences were detected on the time-stable piezoelectric response of the composites (≈ -28 pC.N−1) with distinct ferrite fillers and for the same ferrite content of 10wt.%. Magnetic hysteresis loops from pure ferrite nanopowders showed different magnetic responses. ME results of the nanocomposite films with 10wt.% ferrite content revealed that the ME induced voltage increases with increasing DC magnetic field until a maximum of 6.5 mV∙cm−1∙Oe−1, at an optimum magnetic field of 0.26 T, and 0.8 mV∙cm−1∙Oe−1, at an optimum magnetic field of 0.15T, for the CFO/P(VDF-TrFE) and FO/P(VDF-TrFE) composites, respectively. On the contrary, the ME response of the ZMFO/P(VDF-TrFE) exposed no hysteresis and high dependence on the ZMFO filler content. Possible innovative applications such as memories and information storage, signal processing, ME sensors and oscillators have been addressed for such ferrite/PVDF nanocomposites.

Novel anisotropic magnetoelectric effect on δ-FeO(OH)/P(VDF-TrFE) multiferroic composites

The last decade has witnessed an increased research effort on multi-phase magnetoelectric (ME) composites. In this scope, this paper presents the application of novel materials for the development of anisotropic magnetoelectric (ME) sensors based on δ-FeO(OH)/P(VDF-TrFE) composites. The composite is able to precisely determine the amplitude and direction of the magnetic field. A new ME effect is reported in this study, as it emerges from the magnetic rotation of the δ-FeO(OH) nanosheets inside the piezoelectric P(VDF-TrFE) polymer matrix. δ-FeO(OH)/P(VDF-TrFE) composites with 1, 5, 10 and 20 δ-FeO(OH) filler weigh percentage in three δ-FeO(OH) alignment states (random, transversal and longitudinal) have been developed. Results shown that the modulus of the piezoelectric response (10-24 pC.N-1) is stable at least up to three months, the shape and magnetization maximum value (3 emu.g-1) is dependent on δ-FeO(OH) content and the obtained ME voltage coefficient, with a maximum of ≈0.4 mV.cm-1.Oe-1, is dependent on the incident magnetic field direction and intensity. In this way, the produced materials are suitable for innovative anisotropic sensor and actuator applications.

Removal of Erythrosine B dye from water effluents using crop waste pumpkin seed hulls as adsorbent

Erythrosine B is widely used for coloring in various applications, especially in the food industry, despite its already proved toxicity and carcinogenicity. The agrowaste pumpkin seed hulls were applied as potential adsorbent for the removal of Erythrosine from aqueous solutions. Adsorption mechanism and kinetics were analyzed for design purposes. The seed hulls were characterized by specific techniques before and after dye retention. It was found that the attachment of Erythrosine B molecules on adsorbent surface may be attributed to the interactions between carboxyl and/or carbonyl groups of both dye and agrowaste wall components. A univariate approach followed by a factorial design was applied to study and analyze the experimental results as well as to estimate the combined effects of the process factors on the removal efficiency and dye uptake. Adsorption mechanism may be predominantly due to intraparticle diffusion, dependent on pore size. The four equilibrium models applied fitted the data well; the maximum adsorption capacity for Erythrosine was 16.4 mg/g. The results showed that adsorbent is effective for Erythrosine B removal for a large concentration range in aqueous solutions (5400 mg/L) in batch systems.

A construção publicitária da herança da marca Burberry: uma proposta de análise

A herança das marcas de luxo é uma componente da marca (Aaker, 2004), construída numa dimensão intangível — do imaginário (Maffesoli, 2006), do mito, do desejo (Castarède, 2007) — e materializada em vários suportes de comunicação, entre estes, as imagens publicitárias em revistas de moda. Segundo vários autores (Kopnina, 2007; Morris & Nichols, 2013; Moulins & Roux, 2008), a herança das marcas de luxo é representada na publicidade através de uma linguagem simbólica que transmite os valores e emoções da marca, apela à dimensão sensitiva e afetiva dos consumidores e tenta seduzi-los e conquistá-los, articulando o passado, o presente e o futuro, a sua herança (Hill, 2006). No quadro de um projeto de investigação de doutoramento sobre o tema, pretende-se discutir o conceito de herança da marca e o papel da comunicação publicitária no processo de construção da mesma. O foco incide nas marcas de luxo de vestuário, dada a forte carga simbólica que define este segmento (Lipovetsky & Roux, 2005; Lipovetsky, 2007) e a importância vital da dimensão intangível neste setor (Hancock II et al. (Eds.), 2014; Husband & Chadha, 2007; Kapferer & Bastien, 2009a; Okonkwo, 2007; Tungate, 2009). Como suporte teórico para esta discussão, articulam-se saberes provenientes da gestão da marca, do marketing, da sociologia e da filosofia. Por ser uma marca que investe na construção da sua herança e na criação de produtos icónicos, nomeadamente o trench coat (Moore & Birtwistle, 2004), propomos ilustrar a nossa reflexão com o exemplo da marca britânica Burberry e das suas imagens publicitárias. Para o efeito, recorremos às últimas 4 imagens publicitárias da Burberry, publicadas na Vogue UK, por ser o país de origem da marca. Assim, iremos 1) analisar a herança da Burberry e o papel da trench coat nesta construção e no percurso da marca; 2) identificar, nas imagens, os elementos sígnicos que remetem para a herança da Burberry; 3) relacionar estes elementos com a história e o percurso da Burberry para compreender a forma como estas imagens fazem do trench coat um produto icónico da marca. Assim, este trabalho, no quadro do nosso projeto de investigação de doutoramento, permite-nos aprofundar conceitos e relações centrais na problemática tecida e testar caminhos para a sua exploração empírica.

Regulation of human mesenchymal stem cell osteogenesis by specific surface density of fibronectin: a gradient study

 The success of synthetic bone implants requires good interface between the material and the host tissue. To study the biological relevance of fi bronectin (FN) density on the osteogenic commitment of human bone marrow mesenchymal stem cells (hBMMSCs), human FN was adsorbed in a linear density gradient on the surface of PCL. The evolution of the osteogenic markers alkaline phosphatase and collagen 1 alpha 1 was monitored by immunohistochemistry, and the cytoskeletal organization and the cell-derived FN were assessed. The functional analysis of the gradient revealed that the lower FN-density elicited stronger osteogenic expression and higher cytoskeleton spreading, hallmarks of the stem cell commitment to the osteoblastic lineage. The identifi cation of the optimal FN density regime for the osteogenic commitment of hBM-MSCs presents a simple and versatile strategy to signifi cantly enhance the surface properties of polycaprolactone as a paradigm for other synthetic polymers intended for bone-related applications.

Para uma reconfiguração da publicidade na sociedade

Olhemos para a publicidade como um meio de organizar o social. Temas como a sustentabilidade e a responsabilidade social, na ordem do dia, entram nesta equação, desafiando-nos a pensar no papel da comunicação e da publicidade no processo de transformação das mentalidades. O desafio pressupõe um outro: a urgência da reconfiguração do papel da publicidade na sociedade, reconhecendo-lhe, em definitivo, novas funções. Em concreto, propomos olhar a publicidade como meio de exercer cidadania e de promover a sustentabilidade ambiental e social. Valorizar o seu potencial de persuasão e criatividade a favor da mudança social. Porém, esta não é tarefa de constatação óbvia. Historicamente, a publicidade tem carregado um fardo pejorativo, sendo apontada como manipuladora e causadora do desejo de consumo, o que nos parece uma menorização do discernimento do cidadão. Lipovetsky considera mesmo ser esta uma ideia falsa. “A publicidade não consegue que se deseje o indesejável” (2000: 7). Confrontar o instituído, perspetivando o contributo da comunicação na promoção e consolidação de estratégias sustentáveis é a presente proposta.

A individuação técnica na actualidade

Tese de doutoramento em Sociologia