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Search Results: 1 - 10 of 179686 matches for " Fabrício E. Bortot Coelho "
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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.
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.
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.
End-to-side nerve repair using fibrin glue in rats
Silva, Daniel Nunes e;Coelho, Julice;Frazílio, Fabrício de Oliveira;Odashiro, Alexandre Nakao;Carvalho, Paulo de Tarso Camillo de;Pontes, Elenir Rose Jardim Cury;Vargas, André Ferr?o;Rosseto, Marcelo;Silva, Andréia Brochado Antoniolli da;
Acta Cirurgica Brasileira , 2010, DOI: 10.1590/S0102-86502010000200007
Abstract: purpose: to evaluate axonal regeneration after end-to-side nerve repair with fibrin glue in rats. methods: forty-five wistar rats were divided into three groups: group a (n=15), were not submitted to surgery (control group); group b (n=15) were submitted to fibular transection without repair; and group c (n=15), were submitted to fibular transection with end-to-side nerve anastomosis using fibrin glue, in the lateral surface of an intact tibial nerve. the three groups were submitted to walking track (30 and 90 days) and posterior morphometrical analysis (90 days). results: the functional tests demonstrated that there was no difference in the walking track during the study in group a (p>0.05). the group b had walking pattern impairment in the two tests (p>0.05). the group c had walking pattern impairment in the first test, with important recovery in the second test (p<0.05). the morphometrical assessment revealed significantly higher number of regenerated mielinates axons in group c, compared to group b (p<0.05). conclusion: the end-to-side nerve repair with fibrin glue shows axonal recovery, demonstrated through functional and morphometrical ways in rats.
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.
Silicon and rice disease management
Rodrigues, Fabrício A;Datnoff, Lawrence E;
Fitopatologia Brasileira , 2005, DOI: 10.1590/S0100-41582005000500001
Abstract: the element silicon (si) is not considered an essential nutrient for plant function. nevertheless, si is absorbed from soil in large amounts that are several fold higher than those of other essential macronutrients in certain plant species. its beneficial effects have been reported in various situations, especially under biotic and abiotic stress conditions. the most significant effect of si on plants, besides improving their fitness in nature and increasing agricultural productivity, is the restriction of parasitism. there has been a considerable amount of research showing the positive effect of si in controlling diseases in important crops. rice (oryza sativa), in particular, is affected by the presence of si, with diseases such as blast, brown spot and sheath blight becoming more severe on rice plants grown in si-depleted soils. the hypothesis underlying the control of some diseases in both mono- and di-cots by si has been confined to that of a mechanical barrier resulting from its polymerization in planta. however, some studies show that si-mediated resistance against pathogens is associated with the accumulation of phenolics and phytoalexins as well as with the activation of some pr-genes. these findings strongly suggest that si plays an active role in the resistance of some plants to diseases rather than forming a physical barrier that impedes penetration by fungal pathogens.
ESTRESSE OXIDATIVO EM CéLULAS VEGETAIS MEDIANTE ALELOQUíMICOS
Dias de Almeida,Gustavo; Zucoloto,Moises; Caldas Zetun,Mariana; Coelho,Inácio; Moreira Sobreir,Fabrício;
Revista Facultad Nacional de Agronomía, Medellín , 2008,
Abstract: allelopathy is an interaction among two organisms, where one of that is affected and the other stays stable. it can be source for discoveries of new natural phytotoxic compounds with low toxicity to the organisms that are not target of control. most of the allelochemicals are secondary metabolites like terpenoids, phenolic compounds, organic cyanides and longchain fatty acids. the performance of the allelochemicals can be different according the situations, and it affects a great number of biochemical reactions, resulting in different physiologic modifications in the plants. allelochemicals could affect different pathways, like, the enzymatic activity, division and structure of cells, permeability of the membranes and ions reception, culminating in reduction or inactivation of the germination and plant growth. effects of the allelochemicals on the photosynthesis and breathing has been better characterized, however, several researches had demonstrated the performance of those compounds in oxidative stress, resulting in an increase of oxygen reactive species production which in high concentrations are harmful to cells. in that way, the knowledge of mechanisms of allelochemicals performance is necessary for the development of sustainable techniques in agriculture.
Avalia??o do estado nutricional do nitrogênio em batateira por meio de polifenóis e clorofila na folha
Coelho, Fabrício Silva;Fontes, Paulo Cezar Rezende;Finger, Fernando Luiz;Cecon, Paulo Roberto;
Pesquisa Agropecuária Brasileira , 2012, DOI: 10.1590/S0100-204X2012000400015
Abstract: the objective of this work was to evaluate the effect of n rates on physiological indexes related to nitrogen nutrition in potato, and to verify the possibility of indirectly estimating leaf n contents. flavonol (flvi), chlorophyll (chli), and the nitrogen balance (nbi) indexes were evaluated, and estimations of leaf n contents were made at 21 and 42 days after emergence using the dualex leaf?clip instrument. the experiment was carried out from november 2010 to february 2011, in a randomized complete block design, with five n rates (0, 50, 100, 200, and 300 kg ha?1 of n, applied as urea) at pre?planting, and four replicates. there was an increase in chli and nbi and a decrease in flvi with the increasing n doses. the indexes determined with dualex were correlated with n and extractable chlorophyll content in the fourth leaf and with potato tuber yields. dualex can be used to evaluate n nutritional status in potato plants, and for the prognosis of final tuber yield with readings.
Causas e conseqüências de quedas de idosos atendidos em hospital público
Fabrício,Suzele Cristina Coelho; Rodrigues,Rosalina A Partezani; Costa Junior,Moacyr Lobo da;
Revista de Saúde Pública , 2004, DOI: 10.1590/S0034-89102004000100013
Abstract: objective: to investigate the history of accidental falls reported by older adults, identifying possibly related factors, as well as place of occurrence, causes, and consequences. methods: the sample investigated included 50 older adults, of both sexes, ages 60 years or older, living in the city of ribeir?o preto, southeastern brazil, who had been seen at two inpatient units of a public hospital. patient records were examined and household visits carried out for the application of a structured questionnaire including open, closed, and mixed questions related to the fall. results: data obtained show a reality not substantially different from that observed in other countries. most events occurred among older women (66%), with mean age 76 years, and at home. causes were mainly related to physical environment (54%), and brought serious consequences to the subjects, fractures being the most common outcome (64%). falls had a great impact on subjects' lives in terms of activities such as: lying down/getting up, walking on plain surfaces, cutting toenails, bathing/showering, walking outside home, taking care of financial issues, shopping, using public transportation, and climbing stairs. conclusions: the study demonstrated that falls occurred among older adults have serious physical, psychological, and social consequences, reinforcing the need for fall prevention, in order to ensure greater quality of life, autonomy, and independence for the elderly.
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