An integrated recycling approach for GFRP pultrusion wastes: recycling and reuse assessment into new composite materials using Fuzzy Boolean Nets

In this study, efforts were made in order to put forward an integrated recycling approach for the thermoset based glass fibre reinforced polymer (GPRP) rejects derived from the pultrusion manufacturing industry. Both the recycling process and the development of a new cost-effective end-use application for the recyclates were considered. For this purpose, i) among the several available recycling techniques for thermoset based composite materials, the most suitable one for the envisaged application was selected (mechanical recycling); and ii) an experimental work was carried out in order to assess the added-value of the obtained recyclates as aggregates and reinforcement replacements into concrete-polymer composite materials. Potential recycling solution was assessed by mechanical behaviour of resultant GFRP waste modified concrete-polymer composites with regard to unmodified materials. In the mix design process of the new GFRP waste based composite material, the recyclate content and size grade, and the effect of the incorporation of an adhesion promoter were considered as material factors and systematically tested between reasonable ranges. The optimization process of the modified formulations was supported by the Fuzzy Boolean Nets methodology, which allowed finding the best balance between material parameters that maximizes both flexural and compressive strengths of final composite. Comparing to related end-use applications of GFRP wastes in cementitious based concrete materials, the proposed solution overcome some of the problems found, namely the possible incompatibilities arisen from alkalis-silica reaction and the decrease in the mechanical properties due to high water-cement ratio required to achieve the desirable workability. Obtained results were very promising towards a global cost-effective waste management solution for GFRP industrial wastes and end-of-life products that will lead to a more sustainable composite materials industry.

Re-use assessment of thermoset composite wastes as aggregate and filler replacement for concrete-polymer composite materials: a case study regarding GFRP pultrusion wastes

Glass fibre-reinforced plastics (GFRP), nowadays commonly used in the construction, transportation and automobile sectors, have been considered inherently difficult to recycle due to both the cross-linked nature of thermoset resins, which cannot be remoulded, and the complex composition of the composite itself, which includes glass fibres, polymer matrix and different types of inorganic fillers. Hence, to date, most of the thermoset based GFRP waste is being incinerated or landfilled leading to negative environmental impacts and additional costs to producers and suppliers. With an increasing awareness of environmental matters and the subsequent desire to save resources, recycling would convert an expensive waste disposal into a profitable reusable material. In this study, the effect of the incorporation of mechanically recycled GFRP pultrusion wastes on flexural and compressive behaviour of polyester polymer mortars (PM) was assessed. For this purpose, different contents of GFRP recyclates (0%, 4%, 8% and 12%, w/w), with distinct size grades (coarse fibrous mixture and fine powdered mixture), were incorporated into polyester PM as sand aggregates and filler replacements. The effect of the incorporation of a silane coupling agent was also assessed. Experimental results revealed that GFRP waste filled polymer mortars show improved mechanical behaviour over unmodified polyester based mortars, thus indicating the feasibility of GFRP waste reuse as raw material in concrete-polymer composites.

Mix design process of polyester polymer mortars modified with recycled GFRP waste materials

In this study, the effect of incorporation of recycled glass fibre reinforced plastics (GFRP) waste materials, obtained by means of shredding and milling processes, on mechanical behaviour of polyester polymer mortars (PM) was assessed. For this purpose, different contents of GFRP recyclates, between 4% up to 12% in weight, were incorporated into polyester PM materials as sand aggregates and filler replacements. The effect of the addition of a silane coupling agent to resin binder was also evaluated. Applied waste material was proceeding from the shredding of the leftovers resultant from the cutting and assembly processes of GFRP pultrusion profiles. Currently, these leftovers as well as non-conform products and scrap resulting from pultrusion manufacturing process are landfilled, with additional costs to producers and suppliers. Hence, besides the evident environmental benefits, a viable and feasible solution for these wastes would also conduct to significant economic advantages. Design of experiments and data treatment were accomplish by means of full factorial design approach and analysis of variance ANOVA. Experimental results were promising toward the recyclability of GFRP waste materials as partial replacement of aggregates and reinforcement for PM materials, with significant improvements on mechanical properties of resultant mortars with regards to waste-free formulations.

Sustainable waste recycling solution for the glass fibre reinforced polymer composite materials industry

In this paper the adequacy and the benefit of incorporating glass fibre reinforced polymer (GFRP) waste materials into polyester based mortars, as sand aggregates and filler replacements, are assessed. Different weight contents of mechanically recycled GFRP wastes with two particle size grades are included in the formulation of new materials. In all formulations, a polyester resin matrix was modified with a silane coupling agent in order to improve binder-aggregates interfaces. The added value of the recycling solution was assessed by means of both flexural and compressive strengths of GFRP admixed mortars with regard to those of the unmodified polymer mortars. Planning of experiments and data treatment were performed by means of full factorial design and through appropriate statistical tools based on analyses of variance (ANOVA). Results show that the partial replacement of sand aggregates by either type of GFRP recyclates improves the mechanical performance of resultant polymer mortars. In the case of trial formulations modified with the coarser waste mix, the best results are achieved with 8% waste weight content, while for fine waste based polymer mortars, 4% in weight of waste content leads to the higher increases on mechanical strengths. This study clearly identifies a promising waste management solution for GFRP waste materials by developing a cost-effective end-use application for the recyclates, thus contributing to a more sustainable fibre-reinforced polymer composites industry.

Concepção de uma aplicação móvel no âmbito da ecologia e sustentabilidade ambiental

Trabalho de projeto apresentado à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Audiovisual e Multimédia.

O panorama do audiovisual infantil em Portugal: a problemática da surdez equacionada na concepção de filmes de animação

Dissertação apresentada à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Audiovisual e Multimédia.

Low-loss austempered ductile iron gears: experimental evaluation comparing materials and lubricants

An experimental study to evaluate the power dissipation of gears was performed. Three low-loss gear models were manufactured using standard 20° pressure angle tools. Austempered ductile iron (ADI) and 20MnCr5 carburized steel gears were tested in an FZG gear test machine using mineral, ester and polyalphaolephine (PAO)-based oils. The results compare power dissipation, the influence of different tooth flank geometries, materials and lubricants. This work concludes that conventional power-transmission gears can be replaced by these improved and more efficient low–loss models, which can be produced using common tools and that steel gears can be successfully replaced by austempered ductile iron gears.

Effects of oxidante acid treatments on carbon-templated hierarchical SAPO-11 materials: synthesis, characterization and catalytic evaluation in n-decane hydroiosomerization

Hierarchical SAPO-11 was synthesized using a commercial Merck carbon as template. Oxidant acid treatments were performed on the carbon matrix in order to investigate its influence on the properties of SAPO-11. Structural, textural and acidic properties of the different materials were evaluated by XRD, SEM, N-2 adsorption, pyridine adsorption followed by IR spectroscopy and thermal analyses. The catalytic behavior of the materials (with 0.5 wt.% Pt, introduced by mechanic mixture with Pt/Al2O3), were studied in the hydroisomerization of n-decane. The hierarchical samples showed higher yields in monobranched isomers than typical microporous SAPO-11, as a direct consequence of the modification on both porosity and acidity, the later one being the most predominant. (C) 2014 Elsevier B.V. All rights reserved.

From cellulosic based liquid crystalline sheared solutions to 1D and 2D soft materials

Liquid crystalline cellulosic-based solutions described by distinctive properties are at the origin of different kinds of multifunctional materials with unique characteristics. These solutions can form chiral nematic phases at rest, with tuneable photonic behavior, and exhibit a complex behavior associated with the onset of a network of director field defects under shear. Techniques, such as Nuclear Magnetic Resonance (NMR), Rheology coupled with NMR (Rheo-NMR), rheology, optical methods, Magnetic Resonance Imaging (MRI), Wide Angle X-rays Scattering (WAXS), were extensively used to enlighten the liquid crystalline characteristics of these cellulosic solutions. Cellulosic films produced by shear casting and fibers by electrospinning, from these liquid crystalline solutions, have regained wider attention due to recognition of their innovative properties associated to their biocompatibility. Electrospun membranes composed by helical and spiral shape fibers allow the achievement of large surface areas, leading to the improvement of the performance of this kind of systems. The moisture response, light modulated, wettability and the capability of orienting protein and cellulose crystals, opened a wide range of new applications to the shear casted films. Characterization by NMR, X-rays, tensile tests, AFM, and optical methods allowed detailed characterization of those soft cellulosic materials. In this work, special attention will be given to recent developments, including, among others, a moisture driven cellulosic motor and electro-optical devices.

A Dobragem em Portugal: novos paradigmas na tradução audiovisual

En un país acostumbrado a una cultura en que domina el subtitulado, se ha podido observar, en la última década, una incremento de productos audiovisuales doblados tanto para cine como para televisión. El fenómeno del doblaje, aún poco conocido y estudiado, podrá llevar a un cambio de actitudes y de hábitos del público portugués. La necesidad de observar y analizar el doblaje en Portugal, así como la voluntad de comprender este fenómeno constituyen la bases de esta tesis, como resultado concreto de una investigación llevada a cabo en el ámbito de los Estudios de Traducción Audiovisual, con vista a la obtención del grado académico de Doctor en Traducción y Paratraducción, otorgado por la Universidad de Vigo. El presente trabajo tiene como punto de partida el macrocontexto de la Traducción Audiovisual, pero se focaliza en el doblaje y, secuencialmente, en la realidad del doblaje en Portugal y en el doblaje de productos infanto-juveniles, incidiendo sobre el humor como un microcosmo relevante, debido a su especificidad en términos lingüísticos y culturales para la observación de este fenómeno. Se comprende la Traducción Audiovisual como mediación lingüística, cultural y semiótica centrada en un producto – el texto audiovisual. Este es el resultado de la acción combinatoria de signos verbales, visuales y auditivos. Cada uno transporta un sentido único e insustituible para la comunicación, ganando nuevos significados en las varias combinaciones creadas por esos mismos signos. Este polimorfismo semiótico se concretiza a través de la conjugación singular y exclusiva de todos los elementos verbales y no verbales, consistiendo en algo más que una suma de factores. Es un nuevo texto que se construye en un momento y en un espacio determinados.En este contexto, sobresale un fenómeno que está ganando más relevancia como modalidad traductora en la televisión portuguesa: la aceptación “inconsciente” del doblaje, ya que los programas doblados con imagen real se están imponiendo gradualmente y el público infanto-juvenil tiene una mayor apetencia por estos productos, contribuyendo así en un consumo creciente del doblaje. Asistiendo a este cambio en los comportamientos, se cuestiona si estaremos frente a un nuevo tipo de espectador, más receptivo al doblaje, una vez que las nuevas generaciones, acostumbradas desde edad temprana a ver programas doblados, pueden cambiar sus preferencias y hábitos televisivos, adoptando una actitud más positiva hacia el doblaje. De esta manera, se considera la hipótesis de que el consumo masivo de productos audiovisuales doblados por los jóvenes actuales llevará a la aceptación del doblaje como medio preferencial de acceso al texto audiovisual, lato senso en el futuro. En este sentido y con el propósito de comprender y describir el fenómeno del doblaje en Portugal, conviene analizar varios aspectos, principalmente los de la oferta de productos audiovisuales doblados, del proceso técnico y profesional, de las preferencias de los receptores, del producto y de la traducción. Desde una perspectiva histórica, en la génesis de la opción por subtitular los productos audiovisuales extranjeros en Portugal, habría un intento de desincentivar el consumo de películas extranjeras y de impulsar la distribución de la producción nacional, que se adecuaba más a los valores del régimen de Salazar. Aún después del cambio de régimen, los subtítulos se mantuvieron como modalidad traductora dominante, que resulta de un proceso de habituación y aculturación que puede explicar el mantenimiento de las preferencias del público portugués durante décadas. Sin embargo, en Portugal se ha asistido al aumento gradual de la oferta televisiva y fílmica, sobre todo desde la introducción de los canales privados de señal abierta y por suscripción. La observación y contabilización de la oferta elevisiva reveló un número significativo de productos audiovisuales doblados en Portugal, dirigidos hacia los segmentos etarios más jóvenes. La hegemonía del doblaje con relación a los subtítulos, en lo que se refiere a la traducción de los productos infanto-juveniles extranjeros, condujo a un incremento del consumo de programas infanto-juveniles doblados. Ante esto y debido a la utilización del doblaje, se constató el dominio de la lengua portuguesa en la programación infanto-juvenil, lo que disminuye el contacto de este público con las lenguas extranjeras. Así se comprobó una tendencia a ampliar el ámbito de acción del doblaje en las emisiones televisivas, respondiendo a las cuotas de lengua portuguesa en la televisión en Portugal. Se imponía así ir remontarse hasta el origen del producto final y comprender cómo funciona el proceso técnico del doblaje. Para eso viví in loco la experiencia de la grabación en estudio, entrevisté personalmente y por correo electrónico a los profesionales del área, vi y analicé documentos de vídeo emitidos en la televisión y en Internet sobre esta actividad profesional. De la observación llevada a cabo en el terreno, se comprobó que el proceso de doblaje en Portugal es, sobre todo, una cadena secuencial de profesionales, que pasa por la intervención de distintos agentes en el texto doblado, no siendo únicamente responsabilidad del traductor. La versión final se somete a la manipulación lingüística de los directores de doblaje, a la adaptación sonora de los técnicos de sonido y a la interpretación de los actores, No se pudo comprobar el grado de responsabilidad de cada interviniente, dado que no fue posible acceder a las primeras versiones traducidas Se ha demostrado que el traductor es uno entre muchos agentes en el proceso técnico y que su intervención termina cuando entrega el texto traducido al director de doblaje. Considerando que en Portugal son los niños y los jóvenes los principales destinatarios del doblaje, se comprobó el perfil heterogéneo de este público, delimitado por franjas etarias y caracterizado por la especificidad de sus competencias lingüísticas, culturales y cognitivas, así como por la inexperiencia vivencial. Este hecho propicia la adopción del doblaje modalidad traductora preferencial para este segmento etario. Se confirmó, como resultado de la observación empírica efectuada, que la tipología de los programas televisivos infanto-juveniles en Portugal es poco diversificada y algo repetitiva, con gran prevalencia de la animación sobre la imagen real. Sin embargo, esta investigación reveló la existencia de un nuevo tipo de formato televisivo, con elevado potencial investigativo y que modificó los hábitos y las costumbres del público infanto-juvenil: las teencoms. Esta nueva tipología televisiva, compuesta por secuencias cortas de historias, por un ritmo acelerado de la acción y un discurso dotado de estructuras discursivas sencillas con un enfoque humorístico de fácil comprensión y asimilación por los espectadores más jóvenes, se emite doblada, contrariamente a la práctica imperante en Portugal de utilizar subtítulos en los programas extranjeros. Después de describir cómo ocurre y se materializa este fenómeno, hace falta comprender el porqué de este cambio de actitud. El doblaje de programas infanto-juveniles puede contener ‘ingredientes’ atractivos que cautivan a este nuevo público, haciéndolo una práctica natural y apetecible. Se cuestiona si los consumidores de programas infanto-juveniles doblados aceptan esta modalidad de TAV (Traducción Audiovisual) como natural e invisible, ya que estos presentan coherencia funcional y, así, garantizan niveles elevados de satisfacción. En este sentido, importa comprender cuáles son los factores de atracción y comprobar la eficacia del producto doblado. Uno de esos factores es el humor, como lo demuestra la cantidad de productos audiovisuales cómicos en Portugal destinados a las franjas etarias más jóvenes. Con relación a la traducción de textos humorísticos, dos ideas figuran en varios estudios: la dificultad en traducir el humor debido a las características lingüístico-culturales de cada comunidad, y la necesidad de recurrir a estrategias funcionalistas para que la comunidad pueda ser replicada en el producto audiovisual doblado. De la misma manera, considero que, por su subjetividad, la transferencia interlingüística del humor parece realmente una de las áreas más complejas para el traductor. Pero desde la óptica del investigador, se reveló como un objeto de análisis productivo y revelador del fenómeno del doblaje.

Mechanical properties of stent-graft materials

An aneurysm is a localized blood-filled dilatation of an artery whose consequences can be deadly. One of its current treatments is endovascular aneurysm repair, a minimally invasive procedure in which an endoprosthesis, called a stent-graft, is placed transluminally to prevent wall rupture. Early stent-grafts were custom designed for the patient through the assembling of off-the-shelf components by the operating surgeon. However, nowadays, stent-grafts have become a commercial product. The existing endoprostheses differ in several aspects, such as shape design and materials, but they have in common a metallic scaffold with a polymeric covering membrane. This article aims to gather relevant information for those who wish to understand the principles of stent-grafts and even to develop new devices. Hence, a stent-graft classification based on different characteristics is presented and the desired features for an ideal device are pointed out. Additionally, the materials currently in use to fabricate this type of endoprosthesis are reviewed and new materials are suggested.

Color and Luminescence stability of selected dental materials in vitro

To study luminescence, reflectance, and color stability of dental composites and ceramics. Materials and Methods: IPS e.max, IPS Classic, Gradia, and Sinfony materials were tested, both unpolished (as-cast) and polished specimens. Coffee, tea, red wine, and distilled water (control) were used as staining drinks. Disk-shaped specimens were soaked in the staining drinks for up to 5 days. Color was measured by a colorimeter. Fluorescence was recorded using a spectrofluorometer, in the front-face geometry. Time-resolved fluorescence spectra were recorded using a laser nanosecond spectrofluorometer. Results: The exposure of the examined dental materials to staining drinks caused changes in color of the composites and ceramics, with the polished specimens exhibiting significantly lower color changes as compared to unpolished specimens. Composites exhibited lower color stability as compared to ceramic materials. Water also caused perceptible color changes in most materials. The materials tested demonstrated significantly different initial luminescence intensities. Upon exposure to staining drinks, luminescence became weaker by up to 40%, dependent on the drink and the material. Time-resolved luminescence spectra exhibited some red shift of the emission band at longer times, with the lifetimes in the range of tens of nanoseconds. Conclusions: Unpolished specimens with a more developed surface have lower color stability. Specimens stored in water develop some changes in their visual appearance. The presently proposed methods are effective in evaluating the luminescence of dental materials. Luminescence needs to be tested in addition to color, as the two characteristics are uncorrelated. It is important to further improve the color and luminescence stability of dental materials.

Pt/Carbon materials as Bi-Functional catalysts for N-decane hydroisomerization

The activity and selectivity of bi-functional carbon-supported platinum catalysts for the hydroisomerization of n-alkanes have been studied. The influence of the properties of the carbon support on the performance of the catalysts were investigated by incorporating the metallic function on a series of carbons with varied porosity (microporous: GL-50 from Norit, and mesoporous: CMK-3) and surface chemistry (modified by wet oxidation). The characterization results achieved with H-2 chemisorption and TEM showed differences in surface metal concentrations and metal-support interactions depending on the support composition. The highest metal dispersion was achieved after oxidation of the carbon matrix in concentrated nitric acid, suggesting that the presence of surface functional sites distributed in inner and outer surface favors a homogeneous metal distribution. On the other hand, the higher hydrogenating activity of the catalysts prepared with the mesoporous carbon pointed out that a fast molecular traffic inside the pores plays an important role in the catalysts performance. For n-decane hydroisomerization of long chain n-alkanes, higher activities were obtained for the catalysts with an optimized acidity and metal dispersion along with adequate porosity, pointing out the importance of the support properties in the performance of the catalysts.

Influence of constraining and confinement in the molecular mobility of low molecular weight materials

Dissertation presented to obtain a Ph.D. Degree in Chemical Physics

O balanced scorecard aplicado a uma pme do setor audiovisual

Mestrado em Contabilidade e Gestão das Instituições