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Search Results: 1 - 10 of 34235 matches for " Fabrício Eduardo Bortot Coelho "
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Solvent Extraction of Citric Acid with Different Organic Phases  [PDF]
Estêv?o Magno Rodrigues Araújo, Fabrício Eduardo Bortot Coelho, Julio Cézar Balarini, Tania Lúcia Santos Miranda, Adriane Salum
Advances in Chemical Engineering and Science (ACES) , 2017, DOI: 10.4236/aces.2017.73023
Abstract: The present work aimed at the study of citric acid solvent extraction in order to establish the composition of the organic phase and to obtain thermodynamic and kinetic data for the chosen system. Discontinuous extraction experiments in a single stage were performed from a synthetic solution of citric acid, with the typical concentration (10% w/v) observed in industrial fermented musts. Exploratory experiments were carried out using different organic phases in order to select the most suitable solvent phase to further continuous extraction tests in a mechanically agitated column. The selected organic phase composition was: Alamine 336, ExxalTM 13 tridecyl alcohol, and the aliphatic diluent EscaidTM 110. Next, the effects of the contact time and of the concentrations of extractant and modifier on the citric acid extraction were studied. Among the investigated conditions, the best one was 10 minutes of contact time, 30% w/v of Alamine 336, and 10% w/v of ExxalTM 13 tridecyl alcohol. For this condition, the equilibrium isotherm (28°C ± 2°C) was determined, and the equilibrium constant was calculated (36.8 (mol·L-1)-1.5). It was considered that trioctylamine and citric acid complexation reaction occurs mainly with non-dissociated citric acid form, because the aqueous feed solutions’ pH is lower than the citric acid pKa1. It was found that 1.5 molecules of the extractant, on average, are required to react with one citric acid molecule, which can indicate that reactions with different extractant/citric acid ratios occur simultaneously. Next, the rate constants for the direct and inverse reactions, 2.10 (mol·L-1)-1.5·s-1 and 5.69 × 10-2 s-1, respectively, were calculated. Coefficients of determination (R2) values higher than 0.93 were found in these calculations, suggesting that the results obtained using a computer modeling would be very close to those results obtained experimentally. Therefore, the present work provides data required to future modelling, design, and simulation of citric acid solvent extraction processes.
Individual and Combined Effects of the Extractant, Surfactant and Modifier Concentrations on the Droplet Coalescence Time of the Primary Emulsion in the Liquid Surfactant Membrane Extraction Process  [PDF]
Adriane Salum, Lorena da Costa Nascimento, Tania Lúcia Santos Miranda, Leandro Dornellas Sampaio Andrade, Cibele Konzen, Julio Cézar Balarini, Estêv?o Magno Rodrigues Araújo, Fabrício Eduardo Bortot Coelho
Advances in Chemical Engineering and Science (ACES) , 2018, DOI: 10.4236/aces.2018.84014
Abstract: In this work, the individual and combined effects of the extractant, surfactant and modifier concentrations on the droplet coalescence time of the primary emulsion in the liquid surfactant membrane extraction process were evaluated, through emulsification experiments. Adogen 464 was used as extractant (carrier), and Escaid 110, as diluent. Two systems were studied. The first one composed by the extractant, the surfactant and the diluent, and the second one composed by the same reagents, but with the addition of 1-decanol as modifier. It was observed that, when the modifier is not present in the membrane phase, the surfactant not only stabilizes the primary emulsion, but, apparently, it also plays a role similar to that of the alcohol, promoting the solvation of the amine in a low polarity diluent. Furthermore, the extractant, a quaternary amine, helps to stabilize the primary emulsion in systems without a modifier. For membrane phases consisting of 1 or 5% w/w of Adogen 464 and 2% or 5% w/w of ECA 4360, a concentration of 3% w/w of 1-decanol was sufficient to promote the solvation of Adogen 464 in Escaid 110 and to obtain a low droplet coalescence time.
Development of a New Bio-Based Insulating Fluid from Jatropha curcas Oil for Power Transformers  [PDF]
José M. G. Evangelista Jr., Fabrício E. Bortot Coelho, Juliana A. O. Carvalho, Estêv?o M. R. Araújo, Tania L. S. Miranda, Adriane Salum
Advances in Chemical Engineering and Science (ACES) , 2017, DOI: 10.4236/aces.2017.72018
Abstract: The present work aims to develop a new vegetable insulating fluid for power transformers based on Jatropha curcas oil. Besides its technical benefits, Jatropha curcas oil has a socio-economic role by promoting income to rural families, contributing to the countryside development and avoiding rural exodus. Thus, the entire transformer oil production (extraction, processing, characterization and accelerated aging) was covered and a new process was developed. For oil extraction, the most suitable process was the solvent extraction (5 mL of hexane per gram of crushed non-peeled seeds during 30 minutes) with an oil yield of 32%. In raw oil processing stage, the degumming, with 0.4 g of phosphoric acid per 100 g of oil, at 70°C, was used to remove phosphatides. Then, free fatty acids were 96% neutralized with a sodium hydroxide solution (0.5% w/w) at room temperature. For the oil clarification, the combination of 5% w/woil of activated carbon and 1% w/woil of MgO resulted in a bright, odorless and clear oil with an acid number of 0.04 mgKOH·g1. The oil drying in a vacuum rotary evaporator, at 70°C, for 2 hours reduced the water content to 177 ppm. The processed oil was characterized following ASTM D6871 methods. This oil presented higher dielectric breakdown voltage (55 kV) than commercial transformer fluids (BIOTEMP?, EnvirotempFR3?, and Bivolt?), which increases transformer safety, capacity and lifetime. In addition, the processed oil has a lower viscosity than BIOTEMP? fluid, which can enhance the heat dissipation efficiency in the transformer. Moreover, the processed oil flash and fire points of 310°C and >340°C, respectively, confirm the great security of vegetable insulating fluids. The analyzed properties of the processed oil fulfill all the ASTM D6871, ABNT NBR 15422 and IEC 62770 specifications. Therefore, Jatropha curcas oil is a potential substitute formineral insulating fluids.
The role of hilar lymphadenectomy in patients subjected to hepatectomy due to colorectal metastasis
Viana, Eduardo Freitas;Herman, Paulo;Coelho, Fabrício Ferreira;Taka, Thomas Augusto;D'Albuquerque, Luiz A. Carneiro;Cecconello, Ivan;
Arquivos de Gastroenterologia , 2011, DOI: 10.1590/S0004-28032011000300012
Abstract: context: hepatectomy is the treatment of choice for colorectal liver metastases, and several studies have shown good results, with 5-year survival rates ranging from 40% to 57%. several clinical and pathological predictive factors for survival after liver resection have been studied. involvement of the hepatic hilum lymph nodes, the incidence of which varies from 2% to 10%, indicates a poor long-term prognosis. results: despite variable results, some authors have reported a not-insignificant improvement in survival rate in liver-metastasis patients with hilar lymph node involvement who undergo combined liver resection and lymphadenectomy. due to the low rates of morbidity and mortality for liver-resection surgery, several specialized centers perform liver resections combined with lymphadenectomies in selected cases. it should be noted that the therapeutic value of systemic lymphadenectomy is not yet entirely understood, and only controlled studies comparing groups with and without lymphadenectomy can fully resolve the issue. conclusion: in any case, hilar lymph node dissection has been shown to be a useful tool for improving the accuracy of extra hepatic disease staging, regardless of its impact on survival.
Compara??o de métodos para mapeamento digital de solos com utiliza??o de sistema de informa??o geográfica
Coelho, Fabrício Fernandes;Giasson, Elvio;
Ciência Rural , 2010, DOI: 10.1590/S0103-84782010005000156
Abstract: soil maps are sources of important information for land planning and management, but are expensive to produce. this paper proposes testing and comparing single stage classification methods (multiple multinomial logistic regression and bayes) and multiple stage classification methods (classification and regression trees (cart), j48 and logistic model trees (lmt)) using geographic information system and terrain parameters for producing soil maps with both original and simplified legend. the database was managed in arcgis computer application in which the variables and the original map were related through training of the algorithms. the results from statistical software weka were implemented in arcgis environment to generate digital soil maps. the terrain parameters that best explained soil distribution were slope, profile and planar curvature, elevation, and topographic wetness index. the multiple stage classification methods showed small improvements in overall accuracies and large improvements in the kappa index. simplification of the original legend significantly increased the producer and user accuracies, however produced small improvements in overall accuracies and kappa index.
Avalia??o da qualidade de mangas 'Tommy Atkins' minimamente processadas
Vilas Boas, Brígida Monteiro;Nunes, Elisangela Elena;Fiorini, Fabrício Vilela Andrade;Lima, Luiz Carlos de Oliveira;Vilas Boas, Eduardo Valério de Barros;Coelho, Ana Helena Romaniello;
Revista Brasileira de Fruticultura , 2004, DOI: 10.1590/S0100-29452004000300040
Abstract: since the popularity of fresh-cut fruits and vegetables has increased lately, due to the convenience and quality aspects, chemical modifications were investigated, in addition to sensory and microbiological aspects of fresh-cut the 'tommy atkins' mangoes were treated with 1% citric acid, 1% ascorbic acid and 1% calcium chloride stored under active modified atmospheres (5% o2 + 5% co2) and refrigerated for 12 days. the following analyses were done: titratable acidity, ph, total soluble solids, total soluble sugars, c vitamin, sensory analysis (taste) and microbiological analyses (filamentous fungus and yeast counting and coliforms at 35 e 45oc). it was concluded that the treatments with 1% citric acid, 1% ascorbic acid and 1% cacl2 didn't influence the shelf-life of the fresh-cut 'tommy atkins' mangoes. according to the sensory and microbiological analyses the useful life is 12 days at 5oc.
Estudo da frequência dos alelos de HLA-DRB1 em pacientes brasileiros com artrite reumatoide
Usnayo, Magali Justina Gómez;Andrade, Luis Eduardo Coelho;Alarcon, Renata Triguenho;Oliveira, Juliana Cardoso;Silva, Gustavo Milson Fabrício;Bendet, Izidro;Burlingame, Rufus;Porto, Luis Cristóv?o;Pinheiro, Geraldo da Rocha Castelar;
Revista Brasileira de Reumatologia , 2011, DOI: 10.1590/S0482-50042011000500007
Abstract: the hla-drb1 alleles encoding an amino acid sequence (qkraa/qrraa/rrraa) at position 70 74 of the third hypervariable region of the β1 chain of the hla-drb1 gene, called shared epitope (se), are associated with increased susceptibility to and severity of rheumatoid arthritis (ra) in different populations. objective: to determine the frequency of hla-drb1 alleles in brazilian patients with ra and their association with rheumatoid factor (rf) and anti-citrullinated peptide antibodies (acpa). methods: four hundred and twelve patients with ra (acr 1987) and 215 controls were included. hla-drb1 typing was performed by use of polymerase chain reaction (pcr) with specific primers and hybridization with sequence-specific oligonucleotide probe (ssop). acpa was measured by use of the elisa technique and rf by nephelometry. the statistical analysis comprised the chi-square and student t tests and logistic regression. results: hla-drb1*04:01, *04:04, *04:05 alleles were associated with ra (p < 0.05); despite the wide confidence interval, it is worth noting the association between the drb1*09:01 allele and ra (p < 0.05). hla-drb1 se+ alleles were observed in 62.8% of the patients and in 31.1% of controls (or 3.62; p < 0.001) and were associated with acpa (or 2.03; p < 0.001). drb1-deraa alleles showed a protective effect against ra (or 0.42; p < 0.001). conclusion: in a sample of brazilian patients with ra, most of whom of mixed heritage, hla-drb1 se+ alleles were associated with susceptibility to disease and presence of acpa.
LEAL, Fabrício Assis,CARVALHO, Carlos Eduardo
Nucleus , 2011,
Abstract: The Wet Bulb Index - Globe Thermometer, IBUTG, has an important role in planning theactivities that happen on the presence of heat load. The legislation provides, based on the IBUTG, two situationsto work intermittently, with rest on the spot and elsewhere. The aim of this study was to evaluate the forestrycomparing the productivity of timber harvested between two groups of workers with and without rest. The studyarea is located beside the highway BR 060, at km 397, Rio Verde/Goiás. The measured plot was planted withEucalyptus urophylla S. T. Blake, with 24.98 hectares. The index was calculated using the formula for outdoorswith solar load. Was monitored throughout the day in the production volume of wood cut (st), according to fivetimes pre-established (09:00, 11:00, 14:00, 16:00 and 18:00). This was a randomized block design (DBC) in afactorial 2 x 5, and T test at 1% significance. The average IBUTG was found to be 25.8 and the system adoptedwas 45 minutes work and 15 minutes of rest. There were no significant differences at the 99% level ofprobability between the variable analyzed for the groups with and without rest. However, there was significantdifference for the times evaluated. It is evident that regardless of IBUTG calculated, the rest could be offered bythe company at no cost to employees, since no statistically significant difference between the schemes of workadopted.O índice de Bulbo úmido - Term metro de Globo, IBUTG, tem papel importante noplanejamento das atividades que acontecem sobre a presen a de carga térmica. A legisla o prevê, com base noIBUTG,duas situa es para trabalho intermitente,com descanso no próprio local e em outro local.O objetivodeste trabalho foi avaliar a explora o florestal comparando a produtividade de madeira cortada entre doisgrupos de trabalhadores, com e sem descanso. A área em estudo está localizada às margens da rodovia BR 060,na altura do km 397, em Rio Verde/Goiás. O talh o avaliado foi plantado com Eucalyptus urophylla S. T. Blake,em 24,98 hectares. O índice foi calculado conforme a fórmula para ambientes externos com carga solar. Paracomparar resultados foi monitorado durante todo o dia a produ o em volume de madeira cortada (st),obedecendo cinco horários pré-estabelecidos (09:00, 11:00, 14:00, 16:00 e 18:00 h).Realizou-se umdelineamento em blocos casualizados (DBC), em esquema fatorial 2 x 5, e teste T ao nível de 99% deprobabilidade. O IBUTG médio encontrado foi de 25,8 e o regime adotado foi de 45 minutos de trabalho e 15minutos de descanso. N o houve diferen as significativas, ao nível de 1% de prob
Condicionamento fisiológico de sementes de milheto
Peske, Fabrício Becker;Novembre, Ana Dionisia da Luz Coelho;
Revista Brasileira de Sementes , 2010, DOI: 10.1590/S0101-31222010000400015
Abstract: the objective of this study was to evaluate the physiological conditioning of three pearl millet seed lots of the brs1501 commercial cultivar. the treatments consisted of untreated seeds, seeds hydrated with pure water and seeds hydrated with water of eight different potentials provided by peg 6000 (-0.1; -0.2; -0.4; -0.6; -0.8; -1.0; -1.2 and -1.4 mpa). the seeds were evaluated for water content, germination (first count of germination and final percentage), seedling emergence (final percentage and seedling emergence speed), accelerated ageing and electrical conductivity. the results showed that pearl millet seeds emit primary roots at 33% water content, but as expected, the higher the peg 6000 concentration, the longer the imbibition period necessary. for the potentials of -1.2 and -1.4 mpa, the seeds did not absorb more than 28% of water, and thus, did not emit primary roots. the pearl millet seeds, cultivar brs 1501, emit the primary root at 33% water content, at a potential of zero mpa. it can be concluded that the physiological conditioning of pearl millet seeds by using pure water or peg 6000, does not interfere in the initial seedling development.
Endividamento público, crescimento, moeda e infla??o: comentário a "Matemática agradável", de Gerson Lima
Leite, Fabrício Pitombo;Aggio, Gustavo de Oliveira;Angeli, Eduardo;
Revista de Economia Política , 2009, DOI: 10.1590/S0101-31572009000400010
Abstract: the paper aims at analyzing the article by gerson lima on the manner by which fiscal deficit should be covered. it presents a more general dynamic model, where the principle of effective demand is explicitly used. by doing that, it is possible to treat as endogenous variables the national income and the government entries, what brings the result that the public debt must not follow an explosive path unless the very restrictive conditions of lima's paper prevail. it also evaluates lima's implicit inflation theory, and argues against his approximation to friedman's framework.
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