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- Electrochemical treatment of sanitary landfill leachatesPublication . Fernandes, Annabel Dias Barrocas; Lopes, Ana Maria CarreiraSanitary landfill leachate is one of the major environmental problems concerning water pollution, since it is a very complex wastewater containing different heavy metals, organic and inorganic compounds, some of them refractory and toxic, which possesses colour and odour. Optimal leachate treatment, in order to fully reduce the negative impact on the environment, is today a challenge, since the conventional treatment methods used are not enough to reach the level of purification needed. For this reason, several advanced technologies have been studied for the treatment of sanitary landfill leachates and among them electrochemical methods have received great attention. In fact, electrochemical technologies have shown high efficiency in the elimination of persistent pollutants and several studies have reported its application in wastewater treatment. The objective of the work described in this thesis was to evaluate the application of two electrochemical methods, electrocoagulation and electrochemical oxidation, in the treatment of sanitary landfill leachates. Studies were performed with different leachate samples, collected at different sanitary landfill facilities, at different points of the treatment plants existed and in different seasons of the year. Different cell configurations and electrode materials were experimented. Operational variables such as applied current/potential, stirring, flow rate and electrolysis time were studied. Pollutants removal, mineralization and biodegradability indexes and energetic costs were also assessed. The results obtained demonstrated that electrocoagulation and electrochemical oxidation are effective technologies to treat leachates from sanitary landfills. Depending on the leachate characteristics, electrochemical treatments can be applied as pre-treatment or post treatment of biological processes. For leachates with high content in organic matter, electrochemical oxidation was more effective when applied after the biological treatment, eliminating the refractory organic matter remaining. Energy consumptions of 15 and 21 W h (g COD)-1 were achieved at laboratory and semi-pilot scales experiments, respectively. For leachates designated as “old” or with low biodegradability index, electrochemical oxidation process was more efficient when applied to the raw leachate, without any kind of pre-treatment. Chemical oxygen demand removals above 90% were achieved with energy consumptions of 78 W h (g COD)−1. For leachates with a high amount of solids, the application of an electrocoagulation process before the electrochemical oxidation enhanced the treatment efficiency. Electrocoagulation assays performed led to reductions in organic load of 50% with energy consumptions of 2 W h (g COD)−1. Furthermore, the combined electrocoagulation/ electrochemical oxidation treatment, when applied to raw leachates, enhances the biodegradability of the organic pollutants, improving the performance of the subsequent biological process. An increase in the biodegradability index from 0.3 to 0.9 was attained for the combined assays performed, with chemical oxygen demand removals above 95%. Moreover, this combined treatment has the advantage of being able to use the simultaneous cathodic reduction to remove heavy metals from the leachate, since these processes reduce the metal ions by depositing them onto the cathode. However, when solids content is low, it is preferable to apply only the electrochemical oxidation process, since it does not have the disadvantage of sludge production. The experiments using Ti/Pt/PbO2 anodes showed that this material can be successfully used for the treatment of sanitary landfill leachates, leading to lower energy consumptions than those obtained with boron doped diamond anodes. Both anode materials presented similar chemical oxygen demand removal kinetics and, despite boron doped diamond anodes yields higher mineralization indexes, Ti/Pt/PbO2 promotes higher levels of total and ammonia nitrogen removals.
- A eficácia de um modelo de intervenção de base counseling de inspiração humanista na mudança da saúde mental e dos recursos internos em jovens estudantesPublication . Pita, Tiago Nuno Gonçalves; Pereira, Henrique MarquesA complexidade relacional, massificação e a exigência de rapidez de resultados experienciados na comunidade educativa requerem cada vez mais intervenções que sejam eficazes e potenciadoras de mudança nos alunos e pessoas que a constitui. Aqui se apresentam os resultados obtidos de uma investigação que tinha como principais objetivos: 1. Medir a Saúde Mental dos estudantes de uma escola secundária com 3º Ciclo Portuguesa; 2. Medir os Recursos Internos dos estudantes de uma escola secundária com 3º Ciclo Portuguesa; 3. Validar o Inventário de Recursos Internos (Marting & Hammer) para uma amostra estudantil Portuguesa; 4. Avaliar a eficácia de um modelo de intervenção em counseling inspirada na abordagem Centrada na Pessoa em estudantes de uma escola secundária com 3º Ciclo em Portugal. A intervenção realizada foi inspirada pela abordagem Centrada na Pessoa desenvolvida por Carl Rogers, sublinhando as condições para uma relação de ajuda e reflexão de emoções. Método: Participantes: amostra A (927 estudantes de uma escola secundária com 3º ciclo do município de Beja, média de idade=15.69, 492 rapazes e 420 raparigas), amostra B – grupo experimental (n=30, média de idades= 14.27, 12 rapazes e 18 raparigas), que voluntariamente procuraram aconselhamento nos Serviços Especializados de Apoio Educativo da escola e a amostra C – grupo de controlo (n=30, média de idades=15 anos, 12 rapazes e 18 raparigas), recrutados para participar numa investigação. Instrumentos: Questionário Sociodemográfico, Inventário de Saúde Mental (Pais-Ribeiro, 2011) e Inventário de Recursos Internos (Marting & Hammer, 2004). Procedimento: Os participantes da amostra A responderam aos instrumentos num único momento (1º, 2º e 3ºs objetivos principais deste trabalho), enquanto que os participantes pertencentes à amostra B e C responderam aos instrumentos em 2 momentos pré-determinados (para o 4º objetivo principal). Somente os participantes da amostra B sofreram a intervenção de counseling inspirado pela abordagem Centrada na Pessoa. No final foram comparados os níveis de saúde mental e recursos internos entre os dois grupos (B e C), sendo esta diferença a medida da eficácia do programa de intervenção. Resultados: A amostra utilizada para medir a saúde mental (amostra A) conseguiu resultados semelhantes aos da validação portuguesa de Pais-Ribeiro (2011), a validação do Inventário de Recursos Internos organizou-se em 5 grandes dimensões (interpessoal, autovalorizarão pessoal, espiritual, preocupação com a integridade e atividade física) e da comparação das médias para as várias dimensões do inventário de saúde mental assim como para o Inventário de Recursos Internos, verificaram-se diferenças estatisticamente significativas no grupo experimental entre o momento pré e pós intervenção no sentido da melhoria da saúde mental. Conclusão: a intervenção inspirada na abordagem Centrada na Pessoa em contexto Escolar que aqui se trabalhou promoveu melhorias significativas na saúde mental dos estudantes revelando-se, portanto, eficaz.
- Layer-by-Layer deposition of bioactive polyelectrolytes with incorporation of antimicrobial agents as a new strategy to develop bioactive textilesPublication . Gomes, Ana Paula de Ascensão Rosa; Gouveia, Isabel Cristina Aguiar de Sousa e Silva; Mano, João Filipe Colardelle da Luz; Queiroz, João António de Sampaio RodriguesPolyelectrolyte multilayer coatings have become a new and general way to functionalize a variety of materials. Particularly, the Layer-by-Layer (LbL) method is a technique developed for the coating of solid surfaces. The LbL technique presents a unique mean to construct surface coatings that can conform to a variety of biomaterial surfaces and serve as matrices enabling controlled delivery of bioactive molecules from surface. As the deposition process is achieved in aqueous medium, incorporation of active agents is possible since the coatings obtained by LbL are less densely packed and this is advantageous for diffusion through the coating. The coating is constructed by the alternate adsorption of oppositely charged polyelectrolytes at the surface of the material, easily obtained when it is dipped in polyelectrolyte solutions. A deposition cycle creates a layer, and these cycles can be repeated as often as needed. This study aims to obtain novel bioactive textiles with potential application as wound-dressings. The biopolymers chosen for the functionalization of cotton (substrate), were chitosan (CH) and alginate (ALG). The multilayer coating of cotton with CH and ALG is constructed by the adsorption of CH and ALG with opposite charge on the surface of cotton substrates. The successive deposition of multilayers of CH and ALG was analyzed by three different techniques. Contact angle between a water droplet and the surface of the sample, cationic dye staining method and analysis by ATR-FTIR (Fourier Transform Infrared spectroscopy with Attenuated Total Reflection). These techniques showed that there was alternating deposition between CH and ALG and the presence of electrostatic bonds between the layers. In order to evaluate the antibacterial activity of the functionalized cotton, the Japanese standard JIS L 1902:2002 for the halo method (qualitative assay), and the absorption method (quantitative test) were assessed. These tests revealed an antibacterial effect on the functionalized cotton for both Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Klebsiella pneumoniae). In addition a method was optimized for incorporating L-cysteine (L-cys) between the layers of CH and ALG deposited on cotton samples by the LbL, in order to obtain a better antimicrobial effect. Several strategies were used and the best results were obtained by the method where the ALG turns into a gel in the presence of calcium, since L-cys can be incorporated directly between the layers of CH and ALG without any covalent bond. Thus, the bioactive L-cys agent was immobilized without losing its bioactive characteristics. These new samples were analyzed for the antibacterial activity against Staphylococcus aureus and Klebsiella pneumoniae according with the previously used standard, and the results showed an increase in the antibacterial effect due to the presence of L-cys. This new coating method has the great advantage to able to select other types of bioactive agents without needing further optimization. In this way, L-Cys was replaced by antimicrobial peptides (AMPs). The reason for the use of AMPs is related with the continuous use of antibiotics which resulted in multiresistant bacterial strains all over the world. Consequently, there is an urgent need to search for alternatives for antibiotics. The AMPs are the new generation of antimicrobials. Four AMPs of different features were used. The depth in which each AMPs is incorporated between the layers was determined by energy dispersive analysis of X-rays (Energy Dispersive X-ray EDS). Results showed, that all AMPs used have a higher antimicrobial effect when compared with previous samples (with and without L-Cys) for both microorganisms and are non-cytotoxic to normal human dermal fibroblasts at the tested Concentrations. This confirms that this new functionalization approach of cotton coated with layers of CH and ALG by the LbL technique with incorporated AMPs leads to good antibacterial and cytotoxicity results, which make them suitable to be used as wound dressings.
- Experimental Study of Two Impinging Jets Aligned With a CrossflowPublication . Barata, Jorge M M; Neves, Fernando M. S. P.; Vieira, Diana; Silva, AndréLaser Doppler measurements provide information on the flowfield created by twin impinging jets aligned with a low velocity crossflow. The experiments were carried out for a Reynolds number based on the jet exit conditions of Rej = 4.3 × 104, an impingement height of 20.1 jet diameters and for a velocity ratio between the jet exit and the crossflow VR = Vj/Uo of 22.5, and an inter-jet spacing of S = 6D. The results show a large penetration of the first (upstream) jet that is deflected by the crossflow and impinges on the ground, giving rise to a ground vortex due to the collision of the radial wall and the crossflow that wraps around the impinging point like a scarf. The second jet (located downstream) is not so affected by the crossflow in terms of deflection, but due to the downstream wall jet that flows radially from the impinging point of the first jet it does not reach the ground. The results indicate a new flow pattern not yet reported so far, that is most relevant for a VSTOL aircraft operating in ground vicinity with front wind or small forward movement may result in enhanced under pressures in the aft part of the aircraft causing a suction down force and a change of the pitching moment towards the ground.
- Comunicação política 2.0: estratégias on-line na campanha eleitoral das eleições legislativas de 2009Publication . Rodrigues, Rosália Isabel Duarte; Bento, António José Ferreira; Serra, Joaquim Mateus PauloA tese “Comunicação Política 2.0: Estratégias On-line na Campanha Eleitoral das Eleições Legislativas de 2009” é um estudo das estratégias de Comunicação Política e de Marketing Político durante uma campanha política decorrente em Portugal. As eleições legislativas de 2009 despoletaram o interesse dos partidos políticos para a utilização da Internet como canal de transmissão de informação de propaganda política e como meio de comunicação entre estes e os cidadãos-eleitores. Neste trabalho analisaremos os sítios do Partido Socialista (PS), o “Movimento Sócrates 2009”,e do Partido Social Democrata (PSD), “Política de Verdade”, que foram criados especificamente para a campanha on-line dos partidos. O período de análise restringe-se ao período oficial da campanha eleitoral, de 12 de Setembro de 2009 a 25 de Setembro de 2009. Deste modo, reflectimos sobre o potencial dos novos media, nomeadamente da Internet e dos portais existentes na Web, e acerca das mudanças que os novos meios de comunicação podem ter nas relações sociais, culturais e políticas, isto é as alterações trazidas aos processos de Comunicação Política e à relação dos cidadãos com a organização da polis e com o regime democrático.
- Impacto tecnológico da realidade aumentada na filosofia Lean ManufacturingPublication . Gil, Paulo Jorge Brás Dos Santos; Santos, Fernando Manuel Bigares CharruaO Lean Manufacturing é uma filosofia de gestão industrial que tem como objetivo identificar e eliminar todos os desperdícios que existam numa empresa. A realidade aumentada é uma tecnologia nova, ainda em desenvolvimento, tanto em termos de software como em termos de hardware. Esta tecnologia é constituída por um equipamento de recolha de imagens, um equipamento de processamento de dados e um equipamento de visualização das imagens recolhidas e processadas. É caraterizada por ser uma tecnologia que funde o ambiente real com o ambiente virtual, para que haja uma interação instantânea entre os dois ambientes. No presente trabalho procura-se demonstrar que a utilização da realidade aumentada pode contribuir para a melhoria de algumas das ferramentas e métodos utilizados na filosofia Lean Manufacturing. Através de vários exemplos e de previsões de aplicação na indústria, tenta-se demonstrar que o impacto tecnológico da realidade aumentada na filosofia Lean Manufacturing é uma mais valia.
- Do juízo médico em Paul Ricoeur. Invitatorium: Mysterium VerumPublication . Rosa, José Maria SilvaA hermenêutica do acto de julgar numa situaçao concreta - por exempio, em contexto ético, moral, político, judiciário, económico, etc. - sempre interessou Paul Ricur. É, efectivamente, nessas "encruziihadas" decisivas que se apura a humanidade do homem; nelas, este é devolvido à sua transcendental capacidade de pensar e agir.
- Desenvolvimento de novos biomateriais para aplicação como substitutos de pelePublication . Ribeiro, Maximiano José Prata; Correia, Ilídio Joaquim Sobreira; Borges, Paula Isabel Teixeira Gonçalves CoutinhoThe skin is the largest organ in mammals and acts as a barrier between the human body and the surrounding environment. It protects the underlying organs and defends the body against nocive agents. After an injury, skin integrity is compromised and the organism triggers the wound healing process for restoring the structure and functions of this organ. Wound healing is an extremely dynamic and interactive biological process that involves extracellular matrix molecules, soluble mediators, various resident cells (fibroblasts and keratinocytes) and infiltrating leukocyte subtypes which, together, act to re-establish the integrity of the damaged tissue and replace the lost one. To improve patients odds of survival and to minimize the loss of skin vital functions, this tissue has to be covered immediately after being damaged. Such highlights the importance of developing new wound dressings that improve the healing process, making it less painful and, simultaneously, contributing for the re-establishment of skin structure and functions in a shorter period of time. In recent years, various dressings have been developed, using natural or synthetic materials, for restoring skin native properties and structure. Although, none of them is capable of fully accomplish this objective. Taking this into account, the main objective of this work was to develop and characterize skin substitutes to be used in the treatment of skin disorders. Natural polymers such as agarose, chitosan and dextran were used for dressings production. Initially, we evaluated the applicability of a chitosan hydrogel as a wound dressing. The morphology of the developed system was characterized by scanning electron microscopy while its cytotoxic profile and degradation by-products were evaluated through in vitro assays. In vivo experiments were also performed to evaluate the potential of the chitosan hydrogel for the treatment of skin burns. The results obtained revealed that the hydrogel developed has the required properties for biomedical application intended, once the in vitro and in vivo assays revealed that chitosan hydrogel and its degradation by-products are biocompatible and possess the ability to promote the healing of skin wounds. In the second study, a dextran hydrogel was loaded with chitosan microparticles containing epidermal and vascular endothelial growth factors for the improvement of wound healing process. The hydrogel morphology and cytotoxicity profile and degradation by-products were characterized by scanning electron microscopy and in vitro assays. Furthermore, in vivo experiments were also performed to evaluate the applicability of the hydrogel for wound healing. The results obtained, revealed that the animals treated with this hydrogel showed a faster wound healing with no signs of local or systemic inflammatory response. Moreover, a unique application per week of this skin substitute allowed a faster healing than that obtained when growth factors were topically applied in the wound every two days. Dextran hydrogel proved that it can be used as a wound dressing and also as a carrier of microparticles containing growth factors involved in wound healing. In the third study, a thermoresponsive chitosan/agarose hydrogel was produced for being used in the wound healing process. The porosity, wettability, hydrophilicity, biocompatibility, and bactericidal activity of the hydrogel were characterized by scanning electron microscopy, studies of water uptake, determination of contact angle, confocal microscopy, cytotoxic assays, determination of minimum inhibitory concentration and biofilm deposition, respectively. The performance of this polymeric matrix in the wound healing process was evaluated through in vitro and in vivo assays. The attained results revealed that the hydrogel promotes cellular adhesion and proliferation and also its bactericidal activity. The in vivo studies showed also an improved healing and the lack of a reactive or a granulomatous inflammatory reaction in the skin lesions treated with this hydrogel. During this PhD, various natural polymers were used to produce three different hydrogels, aimed for wound healing. The in vitro and in vivo assays revealed promising results that may allow their use as skin substitutes in a near future.
- Analysis and development of numerical methodologies for simulation of flow control with dielectric barrier discharge actuatorsPublication . Abdollahzadehsangroudi, Mohammadmahdi; Marques, José Carlos Páscoa; Oliveira, Paulo Jorge dos Santos Pimentel deThe aim of this thesis is to investigate and develop different numerical methodologies for modeling the Dielectric Barrier discharge (DBD) plasma actuators for flow control purposes. Two different modeling approaches were considered; one based on Plasma-fluid model and the other based on a phenomenological model. A three component Plasma fluid model based on the transport equations of charged particles was implemented in this thesis in OpenFOAM, using several techniques to reduce the numerical issues. The coupled plasma-fluid problem involves wide range of length and time scales which make the numerical simulation difficult. Therefore, to obtain stable and accurate results in a reasonable computational run time, several numerical procedures were implemented including: semi-implicit treatment of coupling of Poisson equation and charge density equation, super-time-stepping and operator splitting algorithm. We examined our code for a constant positive voltage, testing for the dependency of the behavior of the current density to the selected numerical scheme. In addition, although there is no clear numerical or experimental benchmark case for DBD plasma actuator problem, the developed plasma solver was compared quantitively and qualitively with several numerical works in the literature. Afterward, the developed numerical methodology was used to explore the possibility of influencing the flow, with higher speed, using nano-second (NS) pulsed DBD plasma actuator. Therefore, the interaction of the transonic flow and actuation effects of DBD plasma actuator with nano second pulsed voltage was simulated. The effect of gas heating and body force was calculated by the plasma solver and was supplied into the gas dynamic solver for simulating the flow field. Moreover, the results of the plasma fluid model were used to develop an energy deposition model. It was shown that the energy deposition model is able to capture the main features of the effect of NS DBD plasma actuators correctly, with less computational time. It was also shown that fast energy transfer, from plasma to fluid, leads to the formation of micro-shock waves that modify locally the features of the transonic flow. Although the numerical efficiency of the plasma fluid model was improved, the computational cost of simulating the effect of DBD plasma actuator on a real scale flow situation was still high. Therefore, a simple model for plasma discharge and its effect on the flow was developed based on scaling of the thrust generated by DBD plasma actuators. The scaled thrust model correctly predicts the nonlinear dependency of the thrust produced and the applied voltage. These scales were then introduced into a simple phenomenological model to estimate and simulate the body force distribution generated by the plasma actuator. Although the model includes some experimental correlations, it does not need any fitting parameter. The model was validated with experimental results and showed better accuracy compared to previous plasma models. Using a simple phenomenological model that was developed here, a numerical study was conducted to investigate and compare the effect of steady and unsteady actuation for controlling the flow at relatively high Reynolds number. Firstly it was shown that the size of the time-averaged separation bubble is greatly reduced and the flow structure is sensitive to the frequency of burst modulation of DBD plasma actuators. The results also confirmed that in the case of unsteady actuation, the burst frequency and burst ratio are crucial parameters for influencing the capability of the actuators to control the flow. It was found that burst frequencies near the natural frequencies of the system were able to excite the flow structure in a resonance mode. This observation also confirmed that with proper frequencies of excitation, the flow structure can be well rearranged and the flow losses can be reduced. In the end, Plasma actuators were used for controlling the flow over the Coanda surface of the ACHEON nozzle. When the plasma actuator was used, it was possible to postpone separation of the flow and increase the deflection angle of the exit jet of the nozzle. To find the optimum position of the actuators, seven DBD actuators in forward forcing mode were placed over the Coanda surface considering the numerically obtained separation points. Results show that when the actuator is placed slightly before the separation point, enhanced thrust vectorizing with the use of DBD actuator is achievable. Preliminary results of the experiments agree with planned/foreseen deflection angle obtained from numerical computation.
- Polyurea dendrimer for efficient cytosolic siRNA deliveryPublication . Restani, Rita; Conde, João; Baptista, Pedro; Cidade, Maria Teresa Varanda; Bragança, Ana; Morgado, Jorge; Correia, Ilídio Joaquim Sobreira; Ricardo, Ana Aguiar; Bonifácio, VascoThe design of small interfering RNA (siRNA) delivery materials showing efficacy in vivo is at the forefront of nanotherapeutics research. Polyurea (PURE-type) dendrimers are ‘smart’ biocompatible 3D polymers that unveil a dynamic and elegant back-folding mechanism involving hydrogen bonding between primary amines at the surface and tertiary amines and ureas at the core. Similarly, to a biological proton pump, they are able to automatically and reversibly transform their conformation in response to pH stimulus. Here, we show that PURE-G4 is a useful gene silencing platform showing no cellular toxicity. As a proof of concept we investigated the PURE-G4-siRNA dendriplex, which was shown to be an attractive platform with high transfection efficacy. The simplicity associated with the complexation of siRNA with polyurea dendrimers makes them a powerful tool for efficient cytosolic siRNA delivery.