New recycling approaches for thermoset polymeric composite wastes – an experimental study on polyester based concrete materials filled with fibre reinforced plastic recyclates

In this study, a new waste management solution for thermoset glass fibre reinforced polymer (GFRP) based products was assessed. Mechanical recycling approach, with reduction of GFRP waste to powdered and fibrous materials was applied, and the prospective added-value of obtained recyclates was experimentally investigated as raw material for polyester based mortars. Different GFRP waste admixed mortar formulations were analyzed varying the content, between 4% up to 12% in weight, of GFRP powder and fibre mix waste. The effect of incorporation of a silane coupling agent was also assessed. Design of experiments and data treatment was accomplished through implementation of full factorial design and analysis of variance ANOVA. Added value of potential recycling solution was assessed by means of flexural and compressive loading capacity of GFRP waste admixed mortars with regard to unmodified polymer mortars. The key findings of this study showed a viable technological option for improving the quality of polyester based mortars and highlight a potential cost-effective waste management solution for thermoset composite materials in the production of sustainable concrete-polymer based products.

The computational role of short-term plasticity and the balance of excitation and inhibition in neural microcircuits: experimental and theoretical analysis

The computations performed by the brain ultimately rely on the functional connectivity between neurons embedded in complex networks. It is well known that the neuronal connections, the synapses, are plastic, i.e. the contribution of each presynaptic neuron to the firing of a postsynaptic neuron can be independently adjusted. The modulation of effective synaptic strength can occur on time scales that range from tens or hundreds of milliseconds, to tens of minutes or hours, to days, and may involve pre- and/or post-synaptic modifications. The collection of these mechanisms is generally believed to underlie learning and memory and, hence, it is fundamental to understand their consequences in the behavior of neurons.(...)

Caracterização experimental de escoamentos em canais de secção composta

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de mestre em Engenharia Civil – Perfil de Construção

El ciclo evolutivo experimental de Diphyllobothrium erinaceieuropei en Paracyclops fimbriatus, larvas de Bufo arenarum y caninos

El objetivo del trabajo fue lograr la reproducción experimental del ciclo evolutivo de Diphyllobothrium erinaceieuropei Rudolphi 1819 (Cestoda, Pseudophyllidea) con la intervención de Paracyclops fimbriatus y larvas de Bufo arenarum como hospedadores intermediarios y caninos como hospedadores definitivos. Los huevos del parásito se obtuvieron de heces de caninos infectados naturalmente y se conservaron refrigerados en agua. Se incubaron 7 días a 25°C para que desarrollaran los coracidios y se pusieron en recipientes que contenían a los copépodos mencionados. Al cabo de 12 días a 22,6°C (promedio) se hallaron procercoides maduros en ellos y se agregaron 10 renacuajos de Bufo arenarum. Estos se examinaron por disección 22, 23, 61 y 107 días después, hallándose en todos 1 o más plerocercoides (Temperatura promedio: 24,9°C). El día 23, de 6 renacuajos se obtuvieron 49 plerocercoides, de los cuales se administraron 28, por vía oral, a una perra. El día 107, 3 de 11 plerocercoides obtenidos de un renacuajo se le dieron a otra perra por la misma vía. Se hallaron huevos del cestode en las heces del primer canino a partir del día 22 posterior a la infección (p.i.) y a los 30 días p.i., segmentos de estróbila. En el segundo canino se hallaron huevos a los 30 días p.i..

Experimental assessment of pressure drop in air stripping columns

One important step in the design of air stripping operations for the removal of VOC is the choice of operating conditions, which are based in the phase ratio. This parameter sets on directly the stripping factor and the efficiency of the operation. Its value has an upper limit determined by the flooding regime, which is previewed using empirical correlations, namely the one developed by Eckert. This type of approach is not suitable for the development of algorithms. Using a pilot scale column and a convenient solution, the pressure drop was determined in different operating conditions and the experimental values were compared with the estimations. This particular research will be incorporated in a global model for simulating the dynamics of air stripping using a multi variable distributed parameter system.

Contributos maternos para a auto-regulação do bebé na situação experimental face-to-face still-face

Dissertação apresentada na Escola Superior de Educação de Lisboa para obtenção do grau de Mestre em Intervenção Precoce

Eosinophil levels in the acute phase of experimental chagas' disease

Eosinophil dynamics, in bone marrow, blood and peritoneal exudate, of resistant C57B1/6 (C57) and susceptible A/Snell (A/Sn) mice was comparatively studied during the acute phase of infection by Trypanosoma cruzi Y strain. A decline was observed in bone marrow eosinophil levels in A/Sn, but not in C57 mice, soon after infection, those of the former remaining significantly below those of the latter up to the 4th day of infection. Bone marrow eosinophil levels of C57 mice declined subsequently to levels comparable to those of A/Sn mice, the number of these cells in this compartment remaining 50% those of non infected controls, in both strains, up to the end of the experiment on the 14th day of infection. The fluctuations in eosinophil levels in blood and peritoneal space were similar in both mice strains studied. Concomitantly with depletion of eosinophils in the marrow, depletion in blood and a marked rise of these cells in the peritoneal space, initial site of infection, occurred in both strains. The difference in eosinophil bone marrow levels, between C57 and A/Sn mice, observed in the first four days of infection, suggests a higher eosinopoiesis capacity of the former in this period, which might contribute to their higher resistance to T. cruzi infection.

Experimental study on polyester based concretes filled with glass fibre reinforced plastic recyclates – a contribution to composite materials sustainability

The development and applications of thermoset polymeric composites, namely fibre reinforced plastics (FRP), have shifted in the last decades more and more into the mass market [1]. Despite of all advantages associated to FRP based products, the increasing production and consume also lead to an increasing amount of FRP wastes, either end-of-lifecycle products, or scrap and by-products generated by the manufacturing process itself. Whereas thermoplastic FRPs can be easily recycled, by remelting and remoulding, recyclability of thermosetting FRPs constitutes a more difficult task due to cross-linked nature of resin matrix. To date, most of the thermoset based FRP waste is being incinerated or landfilled, leading to negative environmental impacts and supplementary added costs to FRP producers and suppliers. This actual framework is putting increasing pressure on the industry to address the options available for FRP waste management, being an important driver for applied research undertaken cost efficient recycling methods. [1-2]. In spite of this, research on recycling solutions for thermoset composites is still at an elementary stage. Thermal and/or chemical recycling processes, with partial fibre recovering, have been investigated mostly for carbon fibre reinforced plastics (CFRP) due to inherent value of carbon fibre reinforcement; whereas for glass fibre reinforced plastics (GFRP), mechanical recycling, by means of milling and grinding processes, has been considered a more viable recycling method [1-2]. Though, at the moment, few solutions in the reuse of mechanically-recycled GFRP composites into valueadded products are being explored. Aiming filling this gap, in this study, a new waste management solution for thermoset GFRP based products was assessed. The mechanical recycling approach, with reduction of GFRP waste to powdered and fibrous materials was applied, and the potential added value of obtained recyclates was experimentally investigated as raw material for polyester based mortars. The use of a cementless concrete as host material for GFRP recyclates, instead of a conventional Portland cement based concrete, presents an important asset in avoiding the eventual incompatibility problems arisen from alkalis silica reaction between glass fibres and cementious binder matrix. Additionally, due to hermetic nature of resin binder, polymer based concretes present greater ability for incorporating recycled waste products [3]. Under this scope, different GFRP waste admixed polymer mortar (PM) formulations were analyzed varying the size grading and content of GFRP powder and fibre mix waste. Added value of potential recycling solution was assessed by means of flexural and compressive loading capacities of modified mortars with regard to waste-free polymer mortars.

Os sessenta anos do Teatro Experimental do Porto (1953-2013)

Portefólio da história do Teatro Experimental do Porto (1953-1013).

Chronic myocardial damage in experimental T. cruzi infection of a new world primate, Cebus sp. monkey

Eighteen Cebus apella monkeys, (juvenile and adult of both sexes) were inoculated five years ago, with three Trypanosoma cruzi strains (CA1, n = 10; Colombian, n=4 and Tulahuen, n=4), either by conjunctival or intraperitoneal route, once or repeatedly. Parasitological, hematological, serological, enzymatic, radiographic, electro and echocardiographic findings have been peviously published15 and they are similar to those observed in human pathology. The most frequent electrocardiographic alteration was right branch bundle block. Six animals, chosen at random, were sacrificed. Those sacrificed 20 to 25 months post-first inoculation showed focal accumuli of leukocytes with myocytolysis. Foci of diffuse interstitial fibrosis with mild infiltrate of leukocytes among fibers were observed in the animals sacrificed 36 to 47 months post-inoculation. No parasites were seen. The lesions were more prominent in the ventricular walls and the septum. The fact that the infiltrates were predominant in the animals sacrificed at a shorter time after first inoculation and that fibrosis was more severe in those sacrificed at a longer time suggests that there is a progression of the infiltrative lesions to fibrosis, with a leukocytic activity indicative of a chronic phase. These lesions are similar to those described in human chronic Chagas' disease. This would demonstrate that this model is useful in evaluating a progress in the knowledge of the pathogenesis which is still a controversial issue, immunology, immunogenesis and chemotherapeutic agents of the chronic and indeterminate phases of this disease.

Avaliação da atividade terapêutica do albendazol sobre infecções experimental e humana pela Hymenolepis nana

Com o intuito de demarcar convenientemente o espectro de atividade do albendazol, no que diz respeito às helmintíases intestinais, foram efetuadas observações referentes à himenolepíase causada por Hymenolepis nana. Nesse contexto, duas ordens de investigações tiveram lugar: a) tratamento de camundongos, renovado depois de transcorridos dez dias, por meio de doses únicas de 25 mg/kg ou 50 mg/kg, sendo que 25 mg/kg de praziquantel e animais que não receberam os antiparasitários, serviram como controles; b) tratamento de crianças e adultos mediante uso de 400 mg cotidianamente, em três oportunidades consecutivas, com repetição após intervalo com duração de dez dias. O estudo concernente aos animais revelou ineficácia do albendazol, pois sistematicamente houve verificação da persistência de vermes vivos no intestino. Por seu turno, só 10% dos indivíduos medicados puderam ser considerados curados. Portanto, pelo menos de acordo com a maneira como procedemos, o albendazol não se afigurou capaz de debelar satisfatoriamente a himenolepíase.

Comportamiento experimental del Sporothrix schenckii y la Leishmania mexicana en el hamster

La descripción macroscópica del proceso de patogénesis en hamsters inoculados subcutáneamente en nariz con Sporothrix schenckii ó Leishmania mexicana spp. proporcionó bases para diferenciar estos dos microorganismos en un modelo animal utilizado comunmente para estudiarlos. Observaciones secuenciales durante 150 días permitieron afirmar que en las infecciones causadas por estos patógenos se presentaron edema y eritema como signos primarios, seguidos de alopecia, necrosis y ulceración. La producción de pus fué una característica distintiva para el S. schenckii. Estos signos clínicos se observaron más temprano en la esporotricosis que en la infección por L. mexicana, mostrando diferencias estadísticas significantes en días promedio de aparición. El presente trabajo muestra que las lesiones producidas tanto por el S. schenckii como la L. mexicana en este modelo experimental comparten signos clínicos, pero el tiempo de aparición de los mismos y su frecuencia relativa permiten diferenciarlas. Las condiciones de inoculación como: cepa de los microorganismos, dosis del inóculo, sitio y vía de inoculación, deben tenerse presentes en la evaluación de su comportamiento experimental.

Leishmaniose cutânea experimental. III- Aspectos histopatológicos do comportamento evolutivo da lesão cutânea produzida em Cebus apella (Primates: Cebidae) por Leishmania (Viannia) lainsoni, L. (V.) braziliensis e L. (Leishmania) amazonensis

Estudaram-se os aspectos histopatológicos relativos à evolução da infecção experimental produzida em Cebus apella (Primates: Cebidae) por Leishmania (V.) lainsoni, L. (V.) braziliensis e L. (L.) amazonensis. O exame microscópico de biópsias seqüênciais, obtidas dos animais a intervalos definidos de tempo (a primeira, às 48 ou 72 horas após a inoculação, e as seguintes, a cada 30 dias), mostrou que o desenvolvimento das lesões, independentemente da espécie de Leishmania inoculada, passa por uma seqüência de etapas a nível tecidual - 1) infiltrado inespecífico crônico; 2) nódulo macrofágico (com numerosos parasitas); 3) necrose das células parasitadas; 4) granuloma epitelióide; 5) absorção da área necrosada (às vezes formando granuloma de corpo estranho); 6) infiltrado inespecífico crônico residual); e 7) cicatrização - que representaria a formação e a resolução das lesões. Discutiram-se também os prováveis mecanismos imunopatológicos que determinam esta seqüência de eventos e sua possível semelhança com a evolução das lesões na leishmaniose tegumentar humana.

An experimental study on recycling and reuse of pultruded composite material wastes

Glass fibre-reinforced plastics (GFRP) have been considered inherently difficult to recycle due to both: cross-linked nature of thermoset resins, which cannot be remoulded, and complex composition of the composite itself. Presently, most of the GFRP waste is landfilled leading to negative environmental impacts and supplementary added costs. 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, efforts were made in order to recycle grinded GFRP waste, proceeding from pultrusion production scrap, into new and sustainable composite materials. For this purpose, GFRP waste recyclates, were incorporated into polyester based mortars as fine aggregate and filler replacements at different load contents and particle size distributions. Potential recycling solution was assessed by mechanical behaviour of resultant GFRP waste modified polymer mortars. Results revealed that GFRP waste filled polymer mortars present improved flexural and compressive behavior over unmodified polyester based mortars, thus indicating the feasibility of the GFRP industrial waste reuse into concrete-polymer composite materials.

Efeitos de imunopotenciadores não específicos na infecção experimental pelo Schistosoma mansoni: I. levamisole

Os efeitos do levamisole nas alterações histopatológicas, resistência do hospedeiro e quimiotaxia "in vivo" foram estudados na infecção experimental pelo Schistosoma mansoni em camundongos da linhagem C57B1/10. O tratamento profilático resultou em um aumento no número de vermes adultos obtidos pela perfusão e também em uma taxa de mortalidade maior (p < 0,05). As alterações histopatológicas (fígado e intestino) foram similares em todos os grupos. Uma redução significante da quimiotaxia "in vivo" ocorreu em camundongos controles infectados, assim como naqueles submetidos a tratamento profilático com levamisole. A atividade quimiotática atingiu os mesmos níveis dos camundongos controles normais (não-infectados e não-tratados com levamisole), quando o esquema curativo foi usado. O levamisole parece aumentar a susceptibilidade de camundongos da linhagem C57B1/10 à infecção pelo S. mansoni quando administrado antes da infecção e normaliza a atividade quimiotática, quando dado após a infecção.