Prospecção tecnológica de células fotovoltaicas para energia solar

Solar energy presents itself as an excellent alternative for the generation of clean, renewable energy. This work aims to identify technological trends of photovoltaic cells for solar energy. The research is characterized, in relation to nature, to be applied; regarding the approach is qualitative and quantitative; with respect to the objectives, it is exploratory and descriptive; concerning the methodological procedure is considered a bibliographic research with a case study in the case of solar photovoltaic sector. The development of this research began with a literature review on photovoltaic solar energy and technology foresight. Then it led to the technology mapping of photovoltaic solar cells through the analysis of articles and patents. It was later performed the technological prospecting of photovoltaic cells for solar energy through the Delphi method, as well as the construction of the current plan and future technology of photovoltaic cells for the current scenario, 2020 and 2025. The results of this research show that the considered mature technologies (silicon mono and multicrystalline) will continue to be commercially viable within the prospected period (2020-2025). Other technologies that are currently viable (amorphous silicon, cadmium telluride and copper indium selenide / Copper indium gallium diselenide-), may not submit the same condition in 2025. Since the cells of silicon nanowires, dye-sensitized and based on carbon nanostructure, which nowadays are not commercially viable, may be part of the future map of photovoltaic technologies for solar energy.

Ajustes de coeficientes integrantes de processos físicos e bioquímicos na autedepuração em curso de água de médio porte

The mathematical modeling in the simulation of self-purification capacity in lotic environment is an important tool in the planning and management of hydric resources in hydrographic basin scale. It satisfactorily deals with the self-purification process when the coefficients of physical and biochemical processes are calibrated from monitorated water quality data, which was the main focus of this study. The present study was conducted to simulate the behavior of the parameters OD, BOD5, total phosphorus, E. coli, ammonia, nitrite, nitrate and the total metals cadmium, chromium, copper, lead and zinc in the Uberabinha’s lower course (with an approximate annual growth flow between 4-35 m3/s), in a stretch of 19 km downstream of the treated effluent release by the WWTP of the city. The modelings, on the present study, show the importance of constant water quality parameters monitoration over the water course, based on the comparison of the simulations from calibrated coefficients and coefficients obtained in the literature for the period of June until November 2015. After coefficients calibration, there were good adjustments between simulated and measured data for the parameters OD, BOD, Ptotal, ammonia and nitrate and unsatisfactory adjust for the parameters nitrite and E. coli. About the total metals, the adjustments were not satisfactory on the reservoir’s vicinity of the Small Hydropower Plant Martins, due the considerable increase of the bottom sediment in lentic region. The greatest scientific contribution of this study was to calibrate the decay coefficient K and the quantification of the release by the fund S of total metals in watercourse midsize WWTP pollutant load receptor, justified by the lack of studies in the literature about the subject. For the metals cadmium, chromium, copper, lead and zinc, the borderline for K and S calibrated were: 0.0 to 13.0 day-1 and 0.0 to 1.7 g/m3.day; 0.0 to 0.9 day-1 and 0.0 to 7.3 g/m3.day; 0.0 to 25.0 day-1 and 0.0 to 1.8 g/m3.day; 0.0 to 7.0 day-1 and 0.0 to 40.3 g/m3.day; 0.0 to 30.0 day-1 and 0.0 to 70.1 g/m3.day.

Assessment of metals contamination (Cd, Pb, Ni) at the Óbidos Lagoon using Cerastoderma edule as a biomonitoring tool

A poluição marinha é um problema ambiental Mundial que afeta as constituintes bióticas e abióticas do Ecossistema. Os resultados de diversas atividades antropogénicas chegam ao meio marinho através de escorrências terrestres, industriais e agrícolas assim como através de descargas domésticas, causando distúrbios neste Ecossistema. Sendo assim, a avaliação da contaminação por metais é uma das prioridades tendo em conta que estes químicos têm comportamentos acumulativos e podem ser transportados ao longo de grandes distâncias. Nos estuários, os bivalves são componentes chaves das comunidades macrobentónicas devido o seu papel vital na comunidade e também por serem uma ótima fonte de alimentação para os seres Humanos. Na Lagoa de Óbidos, uma das espécies com estas características e intensamente apanhada é o berbigão Cerastoderma edule. Este berbigão foi descrito por vários autores como sendo tolerante a diversos poluentes. Sendo assim, no presente estudo, o principal objetivo foi utilizar C. edule como ferramenta de biomonitorização de contaminações por metais na Lagoa de Óbidos, avaliando a contaminação por Cádmio, Chumbo e Níquel durante as estações do ano de 2009 e 2010 em duas estações de amostragens (estação ML e BSB). Os resultados foram complementados com a análise de contaminações por metais em amostras de águas e sedimentos. Diversas respostas fisiológicas do berbigão foram também averiguadas de modo a perceber os efeitos da presença de metais e sua acumulação. Finalmente, avaliou-se a Dose Semanal Admissível Provisória (DSAP) para o consumo de berbigão para os mínimos e máximos de concentrações de metais detetados em cada estação de amostragem. Todos os metais foram detetados em amostras de água enquanto apenas o Pb foi detetado no sedimento. O Pb e o Ni foram detetados mais vezes na amostras biológicas do que o Cd. No entanto, as contaminações por metais Pb e Cd no berbigão foram frequentemente acima do limiar fixado pelas autoridades responsáveis enquanto o Ni se encontrou perto dos valores legislados. A avaliação da DSAP revelou a necessidade de aumentar a monitorização biológica neste berbigão visto que a dose semanal admissível foi muito baixa para os três metais. De um modo geral, C. edule refletiu as modificações ambientais, respondendo a modificações físico-químicas e contaminações por metais durante o período de estudo em ambas as estações de amostragem. Assim, este estudo permitiu concluir que Cerastoderma edule foi um bom e sensível indicador de contaminações por metais, especialmente para o Pb e preferencialmente para o Ni.

Impact of natural and/or chemical stressors on the freeze-tolerant and euryhaline enchytraeid, Enchytraeus albidus

Rapid climatic changes are taking place in Arctic, subarctic and cold temperate regions, where predictions point to an increase in freeze-thaw events, changes in precipitation, evaporation and salinity patterns. Climate change may therefore result in large impacts in ecosystem functioning and dynamics, especially in the presence of contaminants due to intense anthropogenic activities. Even though multiple stress approaches have received increasing interest in the last decades, the number of such studies is limited. In particular, knowledge on the effect of freezethaw events and salinity fluctuations on ecotoxicology of soil invertebrates is lacking, especially important when considering supralittoral species. Therefore, the aim of this thesis was to investigate the effects of low temperature and salinity fluctuations, singly and in combination with contaminants, in the freeze-tolerant and euryhaline enchytraeid Enchytraeus albidus. The assessment of population level endpoints (survival and reproduction), along with physiological and biochemical parameters such as levels of cryoprotectants, ice/water content, oxidative stress biomarkers, cellular energy allocation, and tissue concentration of chemicals (when applied), provided new and valuable knowledge on the effects of selected physical and chemical stressors in E. albidus, and allowed the understanding of adjustments in the primary response mechanisms that enable worms to maintain homeostasis and survival in harsh environments such as polar and temperate-cold regions. The presence of moderate levels of salinity significantly increased freeze-tolerance (mainly evaluated as survival, cryoprotection and ice fraction) and reproduction of E. albidus. Moreover, it contributed to the readjustments of cryoprotectant levels, restoration of antioxidant levels and changed singnificantly the effect and uptake of chemicals (copper cadmium, carbendazim and 4-nonylphenol). Temperature fluctuations (simulated as daily freeze-thaw cycles, between -2ºC and -4ºC) caused substancial negative effect on survival of worms previsouly exposed to non-lethal concentrations of 4-nonylphenol, as compared with constant freezing (-4ºC) and control temperature (2ºC). The decrease in cryoprotectants, increase in energy consumption and the highest concentration of 4-nonylphenol in the tissues have highlighted the high energy requirements and level of toxicity experienced by worms exposed to the combined effect of contaminants and freezing-thawing events. The findings reported on this thesis demonstrate that natural (physical) and chemical stressors, singly or in combination, may alter the dynamics of E. albidus, affecting not only their survival and reproduction (and consequent presence/distribution) but also their physiological and biochemical adaptations. These alterations may lead to severe consequences for the functioning of the ecosystems along the Arctic, subarctic and cold temperate regions, where they play an important role for decomposition of dead organic matter. This thesis provides a scientific basis for improving the setting of safety factors for natural soil ecosystems, and to underline the integration of similar investigations in ecotoxicology, and eventually in risk assessment of contaminants.

Megabalanus azoricus (Pilsbry, 1916) : building a scientific basis for its management

Tese de Doutoramento, Biologia (Ciências do Mar), 5 de Julho de 2013, Universidade dos Açores.

Remoção de metais pesados em efluentes sintéticos utilizando vermiculita como adsorvente

Heavy metals are used in many industrial processestheirs discard can harm fel effects to the environment, becoming a serious problem. Many methods used for wastewater treatment have been reported in the literature, but many of them have high cost and low efficiency. The adsorption process has been used as effective for the metal remoal ions. This paper presents studies to evaluate the adsorption capacity of vermiculite as adsorbent for the heavy metals removal in a synthetic solution. The mineral vermiculite was characterized by differents techniques: specific surface area analysis by BET method, X-ray diffraction, raiosX fluorescence, spectroscopy in the infraredd region of, laser particle size analysis and specific gravity. The physical characteristics of the material presented was appropriate for the study of adsorption. The adsorption experiments weredriveal finite bath metod in synthetic solutions of copper, nickel, cadmium, lead and zinc. The results showed that the vermiculite has a high potential for adsorption, removing about 100% of ions and with removal capacity values about 85 ppm of metal in solution, 8.09 mg / g for cadmium, 8.39 mg/g for copper, 8.40 mg/g for lead, 8.26 mg/g for zinc and 8.38 mg/g of nickel. The experimental data fit in the Langmuir and Freundlich models. The kinetic datas showed a good correlation with the pseudo-second order model. It was conducteas a competition study among the metals using vermiculiti a adsorbent. Results showed that the presence of various metals in solution does not influence their removal at low concentrations, removing approximat wasely 100 % of all metals present in solutions

Multibiomarker assessment of cadmium-based quantum dots effects in the marine mussel Mytilus galloprovincialis

Tese de Doutoramento, Ciências do Mar, da Terra e do Ambiente, Ramo: Ciências e Tecnologias do Ambiente, Especialização em Ecotoxicologia, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016

Diagnóstico da possível influência da atividade petrolífera em sedimentos de fundo da Bacia Piranhas-Açu, região Baixo Açu/RN

It is located in an area of increasing oil exploration, the region of the Lower Açu is at the mercy of a possible pollution generated by this economic activity, which includes various chemical substances harmful to health, such as metals. This thesis aims to, diagnose the areas of River Piranhas-Açu, a region of the Lower Açu, which are polluted by traces factors and more. In this study, it was determined the concentration of the chemica elements Al, CD, Cr, Cu, Fe, Mn, Ni, P, Pb, V and Zn, through the technique of ICP-OES analysis and the size of sediments and their contents organic matter. Were mapped by GPS, 12 points from collections. The interpretations of the results, together associating that allowed pollution to a possible contamination by oil activity. The results showed tha some regions have low concentrations of cadmium, lead, copper, manganese and zinc unable to promote damage to human health. However, there are places where the concentrations of certain metals chromium, iron and zinc are moderately polluted compared to the results with the reference values of literature and others that are highly polluted by iron. However, due to a greater number of wells in production in those locations, those higher concentrations, it can be suggested a possible influence of oi production in some areas with concentrations of chromium and lead are higher than the rest of the points of monitoring. Moreover, it is observed that the highest levels of metals found in sediment of finer texture and more organic matter content

Remoção de metais pesados de soluções usando um biopolímero

Comunicação seleccionada e artigo em Livro de Actas

Avaliação da composição mineral de vinhos de talha do Alentejo usando ICP-MS

Os Vinhos de Talha do Alentejo representam uma herança da presença romana na península ibérica e a sua compreensão e análise são muito importantes para a sua preservação. O trabalho que aqui se apresenta, representa uma parte de um estudo alargado sobre vinhos de talha que procura compreender a influência do método de vinificação em talha na composição química destes vinhos, de modo a poder caracterizá-los num contexto mais abrangente de preservação de um património cultural. Com este trabalho procurou-se saber se as características únicas destes vinhos, conferem alguma alteração na sua composição mineral e se os valores encontrados estão dentro dos valores de referência, nomeadamente no que diz respeito a questões de segurança alimentar, com particular atenção para alguns metais pesados como o Manganês, Níquel, Cobre, Zinco, Cádmio e Chumbo. Para tal, usámos 16 vinhos tintos, 16 vinhos brancos e 15 vinhos palhetes que foram gentilmente cedidos pela organização do concurso VITIFRADES do ano de 2014, e estudou-se a sua composição química elementar em 32 elementos (Na, Mg, Al, P, K, Ca, Sc, Mn, Fe, Co, Ni, Cu, Zn, Se, Sr, Cd, In, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Er, Tm, Yb, Pb e Bi) através de ICP-MS. Os resultados da análise multielementar permitiram concluir que os valores encontrados para estes vinhos estão dentro dos limites esperados, não se verificando nenhuma contaminação metálica, especialmente no que diz respeito a alguns elementos que podem levantar questões importantes de segurança alimentar devido à sua toxicidade