967 resultados para Shale oils


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Barramundi (Lates calcarifer), a catadromous teleost of commercial interest, perform well when fed a wide range of dietary oils. However, the range of alternative oils now being explored is typically rich in saturated and monounsaturated fatty acids (SFA and MUFA). In this study, the response of juvenile barramundi (47.0 g per fish initial weight) fed isolipidic and isoenergetic diets with 82 g kg−1 added oil was tested. The experimental test diets had a 2 : 1 or 1 : 2 ratio of SFA to MUFA (SFA-D and MUFA-D, respectively) compared to a control diet (CTRL-D) fed for 8 weeks. The diets containing mostly olive oil (dietary MUFA-D) and mostly refined palm oil (dietary SFA-D) did not impact the growth performance or feed utilization parameters of the barramundi. The in vivo beta-oxidation activity was consistent with the dietary fatty acid composition, with the most dominant FA being heavily beta-oxidized. Together, the in vivo whole-body mass balance of fatty acids showed that n-3 long-chain polyunsaturated fatty acids (LC-PUFA) were most efficiently utilized in the SFA-D- and MUFA-D-fed fish. This study provides evidence that additional dietary MUFA and SFA are suitable lipid classes for juvenile barramundi and they are both equally efficient at sparing LC-PUFA from an oxidative fate.

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The results of a recent increase in research interest directed at the inclusion of tallow in fish feed formulations are suggesting tallow is viable as a potential substitute for other alternative lipid sources such as poultry by-product oil. Although strong growth performance data has been shown, reservations still exist regarding reduced digestibility and the potential impacts this could have on performance over the duration of a grow-out period in low temperature conditions. Also little information is yet available on the potential effect of dietary tallow inclusion on final product quality. A large scale farm based study testing the inclusion of tallow at 40% inclusion, partially replacing poultry by-product oil, in commercial diets of Atlantic salmon over a winter grow-out period in southern Tasmania, Australia was conducted. Tallow inclusion had no impact on growth performance or nutrient digestibility. Tallow resulted in a slight improvement in fillet quality exhibiting a significant reduction in n - 6 PUFA and the n6:n3 ratio, and an increased n - 3LC-PUFA tissue deposition. Consumers were unable to display any preference in liking between 3 salmon products (cold smoked, hot smoked, and cooked) as a result of tallow inclusion. This study demonstrates the viability of partial inclusion of tallow in Atlantic salmon diets over a winter grow-out period. Statement of relevance: Improved knowledge of alternative dietary energy sources (oils and fats) to be used in aquafeed, (replacing the increasingly expensive, and diminishingly available, fish oil) is a key area of research towards improved environmental sustainability and economic viability of the aquaculture sector. Following a promising laboratory based, research scale, in vivo trial aimed at assessing the viability of tallow in salmon feed, a larger and longer duration farm-based trial was implemented to validate initial findings. Consumer test of final products (fresh-cooked, hot smoked and cold smoked fillets) showed no modification of sensorial attributes. Tallow is hereto shown to be a highly viable alternative oil for the salmon aquafeed industry.

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Discovering microalgae with high lipid productivity are among the key milestones for achieving sustainable biodiesel production. Current methods of lipid quantification are time intensive and costly. A rapid colorimetric method based on sulpho-phospho-vanillin (SPV) reaction was developed for the quantification of microbial lipids to facilitate screening for lipid producing microalgae. This method was successfully tested on marine thraustochytrid strains and vegetable oils. The colorimetric method results correlated well with gravimetric method estimates. The new method was less time consuming than gravimetric analysis and is quantitative for lipid determination, even in the presence of carbohydrates, proteins and glycerol.

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Most studies on dietary vegetable oil in rainbow trout (Oncorhynchus mykiss) have been conducted on a background of dietary EPA (20 : 5n-3) and DHA (22 : 6n-3) contained in the fishmeal used as a protein source in aquaculture feed. If dietary EPA and DHA repress their endogenous synthesis from α-linolenic acid (ALA, 18 : 3n-3), then the potential of ALA-containing vegetable oils to maintain tissue EPA and DHA has been underestimated. We examined the effect of individual dietary n-3 PUFA on the expression of the biosynthetic genes required for metabolism of ALA to DHA in rainbow trout. A total of 720 juvenile rainbow trout were allocated to twenty-four experimental tanks and assigned one of eight diets. The effect of dietary ALA, EPA or DHA, in isolation or in combination, on hepatic expression of fatty acyl desaturase (FADS)2a(Δ6), FADS2b(Δ5), elongation of very long-chain fatty acid (ELOVL)5 and ELOVL2 was examined after 3 weeks of dietary intervention. The effect of these diets on liver and muscle phospholipid PUFA composition was also examined. The expression levels of FADS2a(Δ6), ELOVL5 and ELOVL2 were highest when diets were high in ALA, with no added EPA or DHA. Under these conditions ALA was readily converted to tissue DHA. Dietary DHA had the largest and most consistent effect in down-regulating the gene expression of all four genes. The ELOVL5 expression was the least responsive of the four genes to dietary n-3 PUFA changes. These findings should be considered when optimising aquaculture feeds containing vegetable oils and/or fish oil or fishmeal to achieve maximum DHA synthesis.

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Este trabalho procurou avaliar a implantação de Gestão pela Qualidade Total - GQT no Serviço de Recursos Humanos - SEREC da Petrobrás, através de uma pesquisa de campo, dentro de um contexto historicista. O problema identificado para a pesquisa foi: quais as possibilidades e dificuldades da implantação da Gestão pela Qualidade Total no SEREC ? Com o intuito de melhor subsidiar a pesquisa, foram estudados os conceitos acerca da formação do petróleo, do gás natural e do xisto; foram resumidamente explicadas cada uma das principais atividades desenvolvidas pela Petrobrás; foram aborbados alguns aspectos históricos que envolveram a sua origem. Em seguida estudou-se a evolução da função RH na Petrobrás, desde a sua criação até o final de 1995. Trataram-se os aspectos que envolveram a implantação da GQT no SEREC, inicialmente percorrendo os princípios e acontecimentos que nortearam sua implantação na Petrobrás-holding. Ao final, analisou-se a pesquisa de campo.

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As preocupações mundiais com o aquecimento global e os efeitos nocivos da utilização de combustíveis fósseis têm fomentado a busca por novos modelos energéticos, baseados em fontes limpas e renováveis, com destaque para os biocombustíveis. Sem menos importância, o esgotamento das reservas mundiais de matérias-primas fósseis, somado às instabilidades geopolíticas nas principais regiões produtoras, impulsionam, cada vez mais, o desenvolvimento destes novos modelos. Neste cenário, o Brasil tem papel de destaque. Líder mundial na produção e consumo de etanol à base de cana-de-açúcar, o país iniciou, em 2005, a inclusão de mais uma fonte de energia renovável em sua matriz energética: a mistura do biodiesel no diesel mineral. O presente trabalho tem como objetivo analisar a competitividade dos principais biocombustíveis brasileiros: o etanol e o biodiesel. Em primeiro lugar, estes produtos foram analisados quanto às suas principais características; em segundo, avaliou-se a competitividade econômica destes combustíveis frente a seus produtos substitutos diretos derivados do petróleo. Finalmente, foram analisados os benefícios (tangíveis e intangíveis) inerentes à utilização dos biocombustíveis, e como estes intangíveis deveriam ser precificados, como forma de atribuir um prêmio aos benefícios que trazem ao meio-ambiente e à sociedade. Esta dissertação pretende servir de base para uma avaliação mais profunda da real competitividade econômica dos biocombustíveis frente aos combustíveis derivados do petróleo, além de colocar em cheque as principais análises atuais e críticas sobre a utilização destes produtos. Além disso, o presente trabalho visa avaliar o potencial e as limitações da produção dos biocombustíveis no Brasil.

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O presente estudo versa sobre os fatores tecnológicos e ambientais que vêm resultando no crescimento da produção de gás natural não convencional nos EUA. Os objetos de analise principais serão as políticas públicas, assim como a dinâmica entre os atores sociais e o ambiente propício que fora criado para que houvesse o adensamento do fomento e do estímulo às inovações tecnológicas sucedidas no setor.

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Este estudo objetivou identificar os stakeholders que influenciam a agenda do gás de xisto no parlamento brasileiro. A pesquisa teve uma abordagem qualitativa, uma vez que não houve preocupação com os números e sim com a percepção dos entrevistados. Além disso, os dados coletados na pesquisa de campo foram interpretados e alinhados com o referencial teórico desse trabalho. Quanto à metodologia, foi classificada como exploratória, uma vez que ainda há pouco conhecimento sobre a influência de grupos de interesse no Congresso Nacional, do tipo pesquisa de campo e de estudo de caso por se tratar especificamente da exploração do gás de xisto. A coleta de dados foi feita por meio de entrevistas e da aplicação de questionário com um roteiro previamente estabelecido. Após a análise dos dados, concluiu-se que há duas correntes que atuam na agenda do gás de xisto. A primeira tem um posicionamento que preza pela precaução, ou seja, é necessário que se descubra os impactos da exploração da atividade no meio ambiente antes que se decida iniciar a exploração e a produção do gás de xisto. A segunda corrente defende a exploração desse gás não convencional como forma de reduzir os custos de produção e aumentar a competitividade do país. Foram identificados 39 stakeholders que influenciam o andamento do Projeto de Lei 6904/2013, que suspende a autorização e a exploração do gás de xisto por um período de cinco anos. Isso mostra que os grupos de interesse, uns mais poderosos que outros, têm papel importante na formulação de políticas públicas e, através do lobby, buscam influenciar os tomadores de decisão de acordo com os seus objetivos.

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How have shocks to supply and demand affected global oil prices; and what are key policy implications following the resurgence of oil production in the United States? Highlights: − The recent collapse in global oil prices was dominated by oversupply. − The future of tight oil in the United States is vulnerable to obstacles beyond oil prices. − Opinions on tight oil from the Top 25 think tank organizations are considered. Global oil prices have fallen more than fifty percent since mid-2014. While price corrections in the global oil markets resulted from multiple factors over the past twelve months, surging tight oil production from the United States was a key driver. Tight oil is considered an unconventional or transitional oil source due to its location in oil-bearing shale instead of conventional oil reservoirs. These qualities make tight oil production fundamentally different from regular crude, posing unique challenges. This case study examines these challenges and explores how shocks to supply and demand affect global oil prices while identifying important policy considerations. Analysis of existing evidence is supported by expert opinions from more than one hundred scholars from top-tier think tank organizations. Finally, implications for United States tight oil production as well as global ramifications of a new low price environment are explored.

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A dynamic headspace solid-phase microextraction (HS-SPME) and gas chromatography coupled to ion trap mass spectrometry (GC–ITMS) method was developed and applied for the qualitative determination of the volatile compounds present in commercial whisky samples which alcoholic content was previously adjusted to 13% (v/v). Headspace SPME experimental conditions, such as fibre coating, extraction temperature and extraction time, were optimized in order to improve the extraction process. Five different SPME fibres were used in this study, namely, poly(dimethylsiloxane)(PDMS),poly(acrylate)(PA),Carboxen-poly(dimethylsiloxane)(CAR/PDMS),Carbowax-divinylbenzene(CW/DVB)and Carboxen-poly(dimethylsiloxane)-divinylbenzene (CAR/PDMS/DVB). The best results were obtained using a 75 m CAR/PDMS fibre during headspace extraction at 40◦C with stirring at 750rpm for 60min, after saturating the samples with salt. The optimised methodology was then appliedtoinvestigatethevolatilecompositionprofileofthreeScotchwhiskysamples—BlackLabel,BallantinesandHighlandClan.Approximately seventy volatile compounds were identified in the these samples, pertaining at several chemical groups, mainly fatty acids ethyl esters, higher alcohols, fatty acids, carbonyl compounds, monoterpenols, C13 norisoprenoids and some volatile phenols. The ethyl esters form an essential group of aroma components in whisky, to which they confer a pleasant aroma, with “fruity” odours. Qualitatively, the isoamyl acetate, with “banana” aroma,wasthemostinteresting.Quantitatively,significantcomponentsareethylestersofcaprilic,capricandlauricacids.Thehighestconcentration of fatty acids, were observed for caprilic and capric acids. From the higher alcohols the fusel oils (3-methylbutan-1-ol and 2.phenyletanol) are the most important ones.

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Untreated effluents that reach surface water affect the aquatic life and humans. This study aimed to evaluate the wastewater s toxicity (municipal, industrial and shrimp pond effluents) released in the Estuarine Complex of Jundiaí- Potengi, Natal/RN, through chronic quantitative e qualitative toxicity tests using the test organism Mysidopsis Juniae, CRUSTACEA, MYSIDACEA (Silva, 1979). For this, a new methodology for viewing chronic effects on organisms of M. juniae was used (only renewal), based on another existing methodology to another testorganism very similar to M. Juniae, the M. Bahia (daily renewal).Toxicity tests 7 days duration were used for detecting effects on the survival and fecundity in M. juniae. Lethal Concentration 50% (LC50%) was determined by the Trimmed Spearman-Karber; Inhibition Concentration 50% (IC50%) in fecundity was determined by Linear Interpolation. ANOVA (One Way) tests (p = 0.05) were used to determinate the No Observed Effect Concentration (NOEC) and Low Observed Effect Concentration (LOEC). Effluents flows were measured and the toxic load of the effluents was estimated. Multivariate analysis - Principal Component Analysis (PCA) and Correspondence Analysis (CA) - identified the physic-chemical parameters better explain the patterns of toxicity found in survival and fecundity of M. juniae. We verified the feasibility of applying the only renewal system in chronic tests with M. Juniae. Most efluentes proved toxic on the survival and fecundity of M. Juniae, except for some shrimp pond effluents. The most toxic effluent was ETE Lagoa Aerada (LC50, 6.24%; IC50, 4.82%), ETE Quintas (LC50, 5.85%), Giselda Trigueiro Hospital (LC50, 2.05%), CLAN (LC50, 2.14%) and COTEMINAS (LC50, IC50 and 38.51%, 6.94%). The greatest toxic load was originated from ETE inefficient high flow effluents, textile effluents and CLAN. The organic load was related to the toxic effects of wastewater and hospital effluents in survival of M. Juniae, as well as heavy metals, total residual chlorine and phenols. In industrial effluents was found relationship between toxicity and organic load, phenols, oils and greases and benzene. The effects on fertility were related, in turn, with chlorine and heavy metals. Toxicity tests using other organisms of different trophic levels, as well as analysis of sediment toxicity are recommended to confirm the patterns found with M. Juniae. However, the results indicate the necessity for implementation and improvement of sewage treatment systems affluent to the Potengi s estuary

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Portland-polymers composites are promising candidates to be used as cementing material in Northeastern oil wells of Brazil containing heavy oils submitted to steam injection. In this way, it is necessary to evaluate its degradation in the commonly acidizind agents. In addition, to identify how aggressive are the different hostile environments it is an important contribution on the decision of the acidic systems to be used in. It was investigated the performance of the Portland-polymer composites using powdered polyurethane, aqueous polyurethane, rubber tire residues and a biopolymer, those were reinforced with polished carbon steel SAE 1045 to make the electrochemical measurements. HCl 15,0 %, HCl 6,0 % + HF 1,5 % (soft mud acid), HCl 12,0 % + HF 3,0 % (regular mud acid) and HAc 10 % + HF 1,5 % were used as degrading environment and electrolytes. The more aggressive acid solution to the plain Portland hardened cement paste was the regular mud acid, that showed loss of weight around 23.0 %, followed by the soft mud acid, the showed 11.0 %, 15.0 % HCl with 7,0 % and, at last the 10.0 % HAc plus HF 1.5 % with just 1.0 %. The powdered polyurethane-composite and the aqueous polyurethane one showed larger durability, with reduction around 87.0 % on the loss of weight in regular mud acid. The acid attack is superficial and it occurs as an action layer, where the degraded layer is responsible for the decrease on the kinetic of the degrading process. This behavior can be seen mainly on the Portland- aqueous polyurethane composite, because the degraded layer is impregnated with chemically modified polymer. The fact of the acid attack does not have influence on the compressive strength or fratography of the samples, in a general way, confirms that theory. The mechanism of the efficiency of the Portland-polymers composites subjected to acid attack is due to decreased porosity and permeability related with the plain Portland paste, minor quantity of Ca+2, element preferentially leached to the acidic solution, wave effect and to substitute part of the degrading bulk for the polymeric one. The electrolyte HAc 10 % + HF 1,5 % was the least aggressive one to the external corrosion of the casing, showing open circuit potentials around +250 mV compared to -130 mV to the simulated pore solution to the first 24 hours immersion. This behavior has been performed for two months at least. Similar corrosion rates were showed between both of the electrolytes, around 0.01 μA.cm-2. Total impedance values, insipient arcs and big polarization resistance capacitive arcs on the Nyquist plots, indicating passivity process, confirm its efficiency. In this way, Portlandpolymers composites are possible solutions to be succeed applied to oilwell cementing concomitant submitted to steam injection and acidizing operation and the HAc 10,0 % + HF 1,5 % is the less aggressive solution to the external corrosion of the casing

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Biodiesel is a fuel obtained from vegetable oils, such as soy, castorbean, among others. The monoester of fatty acid of these oils have chains with mono, di and tri double connections. The presence of these insaturations are susceptible to oxidization. Antioxidants are substances able to prevent oxidization from oils, fats, fat foods, as well as esters of Alquila( biodiesel). The objective of this work is to summarize a new antioxidant from the Cashew Nut Shell Liquid (CNSL) using the electrolysis technique. A current of 2 amperes was used in a single cell of only one group and two eletrodos of stainless steel 304 in a solution of methanol, together with the eletrolits: acetic acid, sodium chloride and sodium hydroxide, for two hours of agitation. The electrolysis products are characterized by the techniques of cromatography in a thin layer, spectroscopy of infrared and gravimetric analysis. The material was submitted to tests of oxidative stability made by the techniques of spectropy of impendancy and Rancimat (EN 14112). The analyses of characterization suggest that the polimerization of the electrolytic material ocurred. The application results of these materials as antioxidants of soy biodiesel showed that the order of the oxidative stability was obtained by both techniques used

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Concern with the environment has lead to an increase in the research for new adsorption techniques, low cost adsorvent materials and with high availability. Many works search the development of higher selectivity modified adsorvents. The Brazil has the second world reserve of oiled shale, because of it, the use of that reject is of great interest. This study has the goal of characterize and analyze the retorted shale, reject of the pirobetuminous shale pyrolysis, and the retorted shale modified through the humid impregnation method, wich the precursors were the metals nitrates ( Cobalt, Nickel and Copper), to the usage has adsorvent materials. The samples were characterized chemically, textually and structurally by the X ray fluorescence (XRF), BET, X ray diffraction (XRD) and scanning electronic microscopy (SEM) techniques. The impregnated samples showed a reduction in the superficial area and in the pore volume when compared with the retorted shale. Besides that, diffractions referred to the impregnated metals where observed in the XRD analysis, wich were the same metals detected in the XRF and SEM analysis. The materials showed homogeneity in it s composition. The results shows that the materials presents adequate adsorption characteristics

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The oil production in mature areas can be improved by advanced recovery techniques. In special, steam injection reduces the viscosity of heavy oils, thus improving its flow to surrounding wells. On the other hand, the usually high temperatures and pressures involved in the process may lead to cement cracking, negatively affecting both the mechanical stability and zonal isolation provided by the cement sheath of the well. The addition of plastic materials to the cement is an alternative to prevent this scenario. Composite slurries consisting of Portland cement and a natural biopolymer were studied. Samples containing different contents of biopolymer dispersed in a Portland cement matrix were prepared and evaluated by mechanical and rheological tests in order to assess their behavior according to API (American Petroleum Institute) guidelines. FEM was also applied to map the stress distribution encountered by the cement at bottom bole. The slurries were prepared according to a factorial experiment plan by varying three parameters, i.e., cement age, contents of biopolymer and water-to-cement ratio. The results revealed that the addition of the biopolymer reduced the volume of free water and the setting time of the slurry. In addition, tensile strength, compressive strength and toughness improved by 30% comparing hardened composites to plain Portland slurries. FEM results suggested that the stresses developed at bottomhole may be 10 to 100 times higher than the strength of the cement as evaluated in the lab by unconfined mechanical testing. An alternative approach is proposed to adapt the testing methodology used to evaluate the mechanical behavior of oilwell cement slurries by simulating the confined conditions encountered at bottornhole