Recuperação avançada de óleos pesados em poços fraturados utilizando aquecimento eletromagnético indutivo

The success achieved by thermal methods of recovery, in heavy oils, prompted the emergence of studies on the use of electromagnetic waves as heat generating sources in oil reservoirs. Thus, this generation is achieved by three types of different processes according to the frequency range used. They are: the electromagnetic induction heating, the resistive and the dielectric, also known as radiation. This study was based on computer simulations in oil reservoirs with characteristics similar to those found in the sedimentary basins of the Brazilian Northeast. All cases studied were simulated using the software STARS, CMG (Computer Group, version 2012.10 Modeling). Some simulations took into account the inclusion of electrically sensitive particles in certain sectors of the reservoir model studied by fracturing. The purpose of this work is the use of the electromagnetic induction heating as a recovery method of heavy oil, to check the influence of these aforementioned particles on the reservoir model used. Comparative analyses were made involving electromagnetic induction heating, the operation of hydraulic fracturing and the injection of water to the different situations of the reservoir model studied. It was found that fracturing the injection well in order that the electromagnetic heating occurs in the same well where there is water injection, there was a considerable increase in the recovery factor and in the cumulative oil production in relation to the models in which hydraulic fracturing occurred in the production well and water injection in the injection well. This is due to the generation of steam in situ in the reservoir.

Mapeamento cromossômico de DNAs repetitivos com fins biotecnológicos em peixes marinhos e interesse comercial - Rachycentridae e Lutjanidae

The Rachycentron canadum species, commonly known as beijupirá or cobia is the only representative of Rachycentridae family which has been increasingly used in marine fish farming, in intensive cultivation. As advantageous features it has easy adaptation, prolific behavior, early growth in captivity and high commercial value. Additionally, specie of Lutjanidae family (Lutjanus synagris, Lutjanus jocu, Lutjanus analis, Lutjanus alexandrei and Ocyurus chrysurus) represents an important fisheries resource in all areas of its occurrence. In Brazil, the commercial exploitation of Lutjanidae which begun in the 60's and 80's, already has showed a decline in catch volumes. This fact suggests that the snappers must have a conservative management. Despite the economic potential, little is known about the genetic and cytogenetic characteristics of these species, especially with respect to repetitive DNA analysis, which represents the major part of the eukaryotes genome, playing important evolutionary roles in the fish genome. Cytogenetic data is increasingly being used in population studies and biotechnological purposes in fishes. The cytogenetical analyzes were performed using classical methods such as Giemsa staining, C-banding and Ag-NORs, fluorochromes base-specific staining (DAPI and MM) and physical mapping of repetitive sequences among which, telomeric sequences, transposons (Tol2), retrotransposons (Rex1 and Rex3), repetitive DNA (microsatellites and Cot-1) and transcriptionally active regions of the 18S and 5S ribosomal genes and histone (H3 and H2BA) by in situ hybridization with fluorescent probes (FISH). The chromosomal patterns obtained contributed to the organization of repetitive sequences in the genome of the species, as well as karyotypical differentiation. Unusual patterns of histone sequences expansion depict the first occurrence in marine fishes. The obtained data provided subsides to the genetic knowledge of the important fisheries resource represented by the species here analyzed, seeking the marine pisciculture improvement.

O impacto da remoção de peixes sobre a dinâmica e estrutura dos grupos funcionais fitoplanctônicos em um lago raso tropical durante uma seca severa

The artifi cial eutrophication is one of the biggest t h reat for the quality of aquatic ecosystems in the whole world. The expectations for the future climatic scenarios in arid and semi - arid regions are intense and frequent droughts enhancing the risk of eutrophicati on and cyanobacterial blooms. Restoration techniques of eutrophic lakes were proposed to reduce nutrient loading and improve the water quality. A successful technique used in temperate regions is the biomanipulation by benthivorous fish removal . Our hypoth esis is that the benthivorous fish removal reduces phytoplankton total biomass and change the composition of phytoplankton functional groups, improving water quality. The aim of the study was evaluate the impact of biomanipulation on phytoplankton function al groups and in the water quality. We applied the technique of biomanipulation in the artificial lake ESEC, in a semi - arid region of Brazil and analyzed the physical and chemical variables and the dynamic of phytoplankton functional groups monthly during November 2012 to August 2013. With the removal of benthivorous fish we observed a significant increase of the euphotic depth, phytoplankton richness and the recruitment of green algae (groups F and J ), indicators of good water quality. However, we did not observe significant differences on total phosphorous concentration and on phytoplankton biomass and diversity. The drought effect in the region during the study was evident , promoting a drastic reduction on water level which influenced the availability of resource and affected phytoplankton community before the biomanipulation. To evaluate the effect of severe drought on the dynamic of phytoplankton functional groups and test if the drought periods are favorable to dominance of cyanobacterial groups, we stu died two artificial neighbors lakes (ESEC and Pocinhos) in a semi - arid tropical region during May 2012 to February 2013. We observed a temporal differentiation of biotic and abiotic variables caused by drought. Both lakes presented reduction of 2 meters of water level and increase on conductivity, turbidity, nutrients concentration and a reduction on water transparency, during the severe drought. The deeper lake (Pocinhos) increased phytoplankton total biomass and presented cyanobacterial functional group d ominance (group S N ) and the shallower lake (ESEC) reduced phytoplankton total biomass and presented dominance of mixotrophic and flagellate functional groups (groups W 1 e W 2 ). Summarizing, the knowledge of the effects of benthivorous fish removal in semi - a rid tropical lakes still unknown and this study had limitations caused by the impact of drought. Thus, it is necessary a long term monitoring to investigate the real effects of biomanipulation on the functioning of the studied ecosystems. Otherwise, period s of drought could have opposite effects (increase or reduction) on total biomass and composition of phytoplankton functional groups. Drought not always leads to dominance of cyanobacterial groups.

Distribuição e uso de habitat por peixes recifais em um gradiente ambiental: estudo de caso em recifes areníticos

There are several abiotic factors reported in the literature as regulators of the distribution of fish species in marine environments. Among them stand out structural complexity of habitat, benthic composition, depth and distance from the coast are usually reported as positive influencers in the diversity of difentes species, including reef fish. These are dominant elements in reef systems and considered high ecological and socioeconomic importance. Understanding how the above factors influence the distribution and habitat use of reef fish communities are important for their management and conservation. Thus, this study aims to evaluate the influence of these variables on the community of reef fishes along an environmental gradient of depth and distance from shore base in sandstone reefs in the coast of state of Rio Grande do Norte, Brazil. These variables are also used for creating a simple predictive model reef fish biomass for the environment studied. Data collection was performed through visual surveys in situ, and recorded environmental data (structural complexity of habitat, type of coverage of the substrate, benthic invertebrates) and ecological (wealth, abundance and reef fish size classes). As a complement, information on the diet were raised through literature and the biomass was estimated from the length-weight relationship of each species. Overall, the reefs showed a low coverage by corals and the Shallow reefs, Intermediate I and II dominated by algae and the Funds by algae and sponges. The complexity has increased along the gradient and positively influenced the species richness and abundance. Both attributes influenced in the structure of the reef fish community, increasing the richness, abundance and biomass of fish as well as differentiating the trophic structure of the community along the depth gradient and distance from the coast. Distribution and use of habitat by recifas fish was associated with food availability. The predictor model identified depth, roughness and coverage for foliose algae, calcareous algae and soft corals as the most significant variables influencing in the biomass of reef fish. In short, the description and understanding of these patterns are important steps to elucidate the ecological processes. In this sense, our approach provides a new understanding of the structure of the reef fish community of Rio Grande do Norte, allowing understand a part of a whole and assist future monitoring actions, evaluation, management and conservation of these and other reefs of Brazil.

Adição de policloreto de alumínio e remoção de peixes bentívoros como técnicas de restauração de lagos rasos do semiárido brasileiro

Eutrophication is the most common cause of water quality degradation in the world. This process occurs by excessive nutrients inputs, nitrogen and phosphorus, to the aquatic systems resulting in algal and cyanobacterial blooms. In shallow lakes these effects are pronounced due to the higher interaction of the lake with watershed, air and sediment. There are innumerous restoration techniques of eutrophied lakes with a range of successful results but there is only one case of successful lake restoration in Brazil: Paranoá Lake in Brasília city. The Brazilian semiarid region has many artificial lakes, named açudes, which are mostly eutrophic and shallow lakes. The eutrophication in these lakes is reported and the phytoplankton community is dominated by potentially toxic cyanobacteria species, mainly Cylindrospermopsis raciborskii. The aim of this thesis is to test techniques for water quality management which can be easily applied in Brazilian semiarid lakes. Results from a laboratory experiment suggest that the addition of a phosphorus sorbent clay associated with an aluminium based coagulant is an effective technique in removing soluble reactive phosphorus and reducing C. raciborskii growth rate – cyanobacteria potentially toxic dominant in reservoirs of Brazilian semiarid – but this effect is dependent on the biomass in the application moment. Results from a field experiment in mesocosm in a eutrophied lake showed that the addition of aluminium based coagulant and removal of benthivorous fish is more efficient in removing total phosphorus and chlorophyll-a from water column than the isolated application of one of the techniques. Lastly, laboratory tests showed that aluminium based coagulant exhibited good performance in removing turbidity and total phosphorus from water of six reservoirs but the efficiency was reduced by algal biomass and pH. The results of this study showed that the improvement in water quality of eutrophied reservoirs in semiarid region is possible through internal loading control by phosphorus precipitation and inactivation in sediments or inhibition of phosphorus release by benthivorous fishes, and also that these results show are additives in water quality improvement.

Adição de policloreto de alumínio e remoção de peixes bentívoros como técnicas de restauração de lagos rasos do semiárido brasileiro

Eutrophication is the most common cause of water quality degradation in the world. This process occurs by excessive nutrients inputs, nitrogen and phosphorus, to the aquatic systems resulting in algal and cyanobacterial blooms. In shallow lakes these effects are pronounced due to the higher interaction of the lake with watershed, air and sediment. There are innumerous restoration techniques of eutrophied lakes with a range of successful results but there is only one case of successful lake restoration in Brazil: Paranoá Lake in Brasília city. The Brazilian semiarid region has many artificial lakes, named açudes, which are mostly eutrophic and shallow lakes. The eutrophication in these lakes is reported and the phytoplankton community is dominated by potentially toxic cyanobacteria species, mainly Cylindrospermopsis raciborskii. The aim of this thesis is to test techniques for water quality management which can be easily applied in Brazilian semiarid lakes. Results from a laboratory experiment suggest that the addition of a phosphorus sorbent clay associated with an aluminium based coagulant is an effective technique in removing soluble reactive phosphorus and reducing C. raciborskii growth rate – cyanobacteria potentially toxic dominant in reservoirs of Brazilian semiarid – but this effect is dependent on the biomass in the application moment. Results from a field experiment in mesocosm in a eutrophied lake showed that the addition of aluminium based coagulant and removal of benthivorous fish is more efficient in removing total phosphorus and chlorophyll-a from water column than the isolated application of one of the techniques. Lastly, laboratory tests showed that aluminium based coagulant exhibited good performance in removing turbidity and total phosphorus from water of six reservoirs but the efficiency was reduced by algal biomass and pH. The results of this study showed that the improvement in water quality of eutrophied reservoirs in semiarid region is possible through internal loading control by phosphorus precipitation and inactivation in sediments or inhibition of phosphorus release by benthivorous fishes, and also that these results show are additives in water quality improvement.

Causas e consequências da onivoria de peixes em ecossistemas aquáticos

Omnivory is a predominant feeding strategy among tropical fishes, but knowledge about its causes and consequences of this pattern is scarce. In this study we hypothesized that tropical fish feed lower in food web as a way to compensate a higher energetic demand, which increases with increasing water temperature and body size. Information about 8172 freshwater and marine fish species from whole world, from tropical and temperate ecosystems, showed that the trophic position of non-carnivore fish decreases with increasing body size in tropical but not in temperate ecosystems. This result indicates that the higher energetic demand of large-bodied tropical fish should exert a selective force in favor of omnivory. As a consequence, trophic dynamics in tropical freshwater ecosystems should have different patterns comparing to temperate ones, with major implications for water management and restoration of eutrophic aquatic ecosystems. Another hypothesis of this work was that effects of tropical omnivorous planktivorous fish on planktonic communities depend of primary producers stoichiometric composition, which depends of light availability relative to nutrients ratios. A mesocosm experiment, manipulating light availability and planktivorous fish presence, confirmed our hypothesis indicating that resource stoichiometric composition (consequently nutritional quality), determine trophic structure of pelagic food webs in tropical lakes. Finally another mesocosm experiment indicated that the removal of omnivorous benthivorous fish should be more efficient than removal of omnivorous planktivorus fish, as a way to improve water quality in tropical lakes and reservoirs. This last experiment showed that omnivorous planktivorous fish increase phytoplankton biomass due to trophic cascade interactions, without increasing nutrient concentrations in the water column. On the other hand, omnivorous benthivorous fish, feeding on detritus and other benthonic food sources and excreting nutrients in the water column, are responsible for translocate nutrient from sediments to the water column, increasing phosphorus pool and phytoplankton biomass. Thereby, internal phosphorus supply should be reduced and water quality of eutrophicated lakes could be improved by removing omnivorous benthivorous fish.

Causas e consequências da onivoria de peixes em ecossistemas aquáticos

Omnivory is a predominant feeding strategy among tropical fishes, but knowledge about its causes and consequences of this pattern is scarce. In this study we hypothesized that tropical fish feed lower in food web as a way to compensate a higher energetic demand, which increases with increasing water temperature and body size. Information about 8172 freshwater and marine fish species from whole world, from tropical and temperate ecosystems, showed that the trophic position of non-carnivore fish decreases with increasing body size in tropical but not in temperate ecosystems. This result indicates that the higher energetic demand of large-bodied tropical fish should exert a selective force in favor of omnivory. As a consequence, trophic dynamics in tropical freshwater ecosystems should have different patterns comparing to temperate ones, with major implications for water management and restoration of eutrophic aquatic ecosystems. Another hypothesis of this work was that effects of tropical omnivorous planktivorous fish on planktonic communities depend of primary producers stoichiometric composition, which depends of light availability relative to nutrients ratios. A mesocosm experiment, manipulating light availability and planktivorous fish presence, confirmed our hypothesis indicating that resource stoichiometric composition (consequently nutritional quality), determine trophic structure of pelagic food webs in tropical lakes. Finally another mesocosm experiment indicated that the removal of omnivorous benthivorous fish should be more efficient than removal of omnivorous planktivorus fish, as a way to improve water quality in tropical lakes and reservoirs. This last experiment showed that omnivorous planktivorous fish increase phytoplankton biomass due to trophic cascade interactions, without increasing nutrient concentrations in the water column. On the other hand, omnivorous benthivorous fish, feeding on detritus and other benthonic food sources and excreting nutrients in the water column, are responsible for translocate nutrient from sediments to the water column, increasing phosphorus pool and phytoplankton biomass. Thereby, internal phosphorus supply should be reduced and water quality of eutrophicated lakes could be improved by removing omnivorous benthivorous fish.

Biocatálise aplicada à valorização de óleos alimentares usados

O crescente consumo de energia, bem como a possibilidade de esgotamento dos recursos não renováveis, tem fomentado a busca de fontes de energia alternativas. O biodiesel é um biocombustível obtido a partir de fontes renováveis e a sua utilização permite reduzir as emissões de gases com efeito de estufa. Nos últimos anos tem-se produzido biodiesel a partir de óleos alimentares usados (OAU), sendo que com esta aplicação valoriza-se um resíduo e simultaneamente produz-se um combustível “verde”. O biodiesel é produzido através das reações de transesterificação e/ou esterificação entre triglicerídeos e/ou ácidos gordos livres e um álcool, na presença de um catalisador. O rendimento do processo está estritamente relacionado com o tipo de catalisador e as condições que este opera. O principal objetivo do presente trabalho consistiu na avaliação do efeito de alguns parâmetros operacionais no desempenho de uma lípase imobilizada (Novozyme® 435), nomeadamente: (i) índice de acidez do óleo, (ii) razão mássica de enzima/óleo e (iii) método regeneração da enzima com vista à sua reutilização. Também foi objeto de estudo do presente trabalho a produção em contínuo, num (bior)reator tubular de leito fixo, de ésteres metílicos de ácidos gordos (FAME) usando a referida enzima. Registou-se um aumento rendimento em com o incremento do índice de acidez do óleo usado, o que indicia que a enzima catalisa simultaneamente as reações de esterificação e transesterificação. Relativamente à razão mássica de enzima/óleo, dentro da gama testada verificou-se um aumento do rendimento em FAME com a concentração da enzima em meio reacional. Dos vários solventes testados, a aplicação de solvente tert-butanol na regeneração (com incubação) da enzima foi o que melhores resultados teve. Finalmente, os resultados obtidos no ensaio de produção de FAME num biorreator contínuo são motivadores, criando expectativas de uma possível aplicação industrial no futuro.

The use of animal processed proteins and fat on the growth performance of rainbow trout (Onchorynchus mykiss)

Hoje em dia a industria da aquacultura enfrenta novos desafios para manter a sustentabilidade econômica de uma forma responsável para o meio ambiente e consumidores. Um dos maiores desafios que apresenta hoje em dia, é o aumento do preço da farinha e óleo de peixe que são os constituintes maioritários da alimentação para os peixes de aquacultura. As PAP’s e gorduras de animais terrestres parecem ser uma alternativa viável, sustentável e menos problemática do que as farinhas e óleos vegetais para substituir a farinha e óleo de peixe. Por esta razão neste trabalho nos procuramos substituir uma pequena parte da farinha e óleo de peixe por alguns produtos provenientes de animais terrestres. Este estudo foi um teste de crescimento para a truta arco-íris (Oncorhynchus mykiss). Inicialmente foram formuladas 4 dietas (CTRL, PAP2, PAP3 and PAP4). Exceptuando o dieta controlo (CTRL) que foi uma dieta comercial, os outros alimentos foram desenhados para substituir a farinha de peixe e outras farinhas vegetais por PAP’s (proteína animal processada) como hidrolisado de farinha de penas, farinha de sangue de suíno e gordura animal processadas como a gordura de aves. O teste foi feito ao longo de 112 dias com checkpoints no dia (30, 60 e 112), onde os peixes eram pesados com excepção do dia 112 onde foram também amostrados para composição corporal e índice hepatossomático. O peso inicial médio dos peixes dos grupos foi 219,7g e o peso médio final foi 488,7g. Não existiram alterações comportamentais nem preferência por nenhuma ração testada e não foram verificadas diferenças estatisticamente significativas (P>0,05) no consumo de ração, crescimento e outros parâmetros de crescimento com a exceção da taxa de eficiência proteica. Foram também verificadas diferenças estatísticas significativas para alguns aspectos da composição corporal, ganhos e retenções. Os resultados demonstram que as substituições feitas não tiveram impacto no crescimentos da truta arco íris mas sim na composição corporal. Apesar disso os resultados não sugerem nenhum problema importante relacionado com o uso de PAP’s na formulação de ração para peixes.

Impacto da acidificação dos oceanos no desenvolvimento embrionário e larvar de peixes marinhos

Devido à acumulação atmosférica de CO2 antropogénico, a pressão parcial de dióxido de carbono (ρCO2) na água do mar aumenta e o pH diminui. Atualmente, este processo conhecido como a acidificação dos oceanos, está a ocorrer a um ritmo mais rápido do que em qualquer outro momento dos últimos 300 milhões de anos, o que leva a um desafio ecológico para os organismos marinhos a nível mundial. Embora este processo afete significativamente mais os organismos marinhos que sintetizam exosqueletos de calcário ou conchas, ainda não está claro como este processo irá afetar organismos calcificados internamente, tais como peixes marinhos. Embora se pense que os peixes adultos são relativamente mais tolerantes a níveis elevados de CO2 ambiental, sabe-se muito pouco sobre a sensibilidade dos estágios iniciais de vida, que são geralmente mais vulneráveis às mudanças ambientais do que os juvenis e os adultos. Determinar que espécies marinhas são sensíveis ou tolerantes aos elevados níveis de CO2 e redução do pH é fundamental para prever os impactos da acidificação dos oceanos nas cadeias alimentares marinhas e nos ecossistemas nos próximos 300 anos. O presente estudo aborda o efeito da acidificação dos oceanos sobre os estágios iniciais de desenvolvimento de três espécies comercialmente importantes, Solea senegalensis, Diplodus sargus, Argyrosomus regius. Estas espécies foram sujeitas a diferentes níveis de pH e ρCO2 (pH 8.0, ~400 μatm; pH 7.8, ~1000 μatm; pH 7.6, ~2000 μatm) desde a fase do ovo até à abertura de boca. Os resultados deste estudo sugerem que a exposição das fases iniciais de vida de Solea senegalensis e Diplodus sargus a elevadas concentrações de CO2 podem levar a taxas de eclosão e crescimento reduzidas e taxas de sobrevivência e peso seco elevados. Quando comparado com os níveis atuais de ρCO2 (400 ppm), a exposição de embriões Argyrosomus regius a 1000 μatm aumentou a sua sobrevivência, crescimento e comprimento total ao fim de 3 dias após eclosão. Não se detetaram diferenças significativas entre tratamentos no que respeita à organogénese e às dimensões e morfologia do ovo. De uma forma geral, este estudo parece indicar que Diplodus sargus e Solea senegalensis são substancialmente mais suscetíveis aos efeitos fisiológicos da acidificação dos oceanos do que Argyrososmus regius que está presumivelmente melhor adaptada às variações das condições ambientais, devido ao seu rápido desenvolvimento e ampla distribuição geográfica.

Los óleos alquídicos Griffin : Composición, propiedades y aplicación

Uno de los principales inconvenientes que tiene la pintura al óleo es su lento secado. Dicho esto, cabe preguntarse si existe algún tipo de pintura que tenga las cualidades de los óleos pero que sequen más rápido que estos. La respuesta, afirmativa, la encontramos en los óleos alquídicos, que en nuestro país únicamente se comercializan bajo la marca Griffin de Winsor & Newton. Se trata de unas pinturas relativamente recientes, poco conocidas por los pintores y muy poco estudiadas. Con el objetivo de paliar estas carencias, el presente artículo contiene las principales conclusiones de un trabajo en el que se ha estudiado la composición de las pinturas Griffin, sus principales características (viscosidad, brillo, flexibilidad, textura, opacidad, secado que es lo que más nos interesa, estabilidad etc.), su aplicación práctica mediante el arte pictórico (soportes, disolventes, reglas para pintar, correcciones, veladuras, barnizado, etc.) y su mezcla con otro tipo de procedimientos pictóricos como el óleo, el acrílico, la cera encáustica y diversos temples (huevo, cola y caseína).