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Luna A.J.,National Institute of Industrial Property | Chiavone-Filho O.,Federal University of Rio Grande do Norte | Machulek A.,Federal University of Mato Grosso do Sul | de Moraes J.E.F.,Federal University of Sao Paulo | Nascimento C.A.O.,University of Sao Paulo
Journal of Environmental Management | Year: 2012

A highly concentrated aqueous saline-containing solution of phenol, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP) was treated by the photo-Fenton process in a system composed of an annular reactor with a quartz immersion well and a medium-pressure mercury lamp (450 W). The study was conducted under special conditions to minimize the costs of acidification and neutralization, which are usual steps in this type of process. Photochemical reactions were carried out to investigate the influence of some process variables such as the initial concentration of Fe2+ ([Fe2+]0) from 1.0 up to 2.5 mM, the rate in mmol of H2O2 fed into the system (FH2O2,in) from 3.67 up to 7.33 mmol of H2O2/min during 120 min of reaction time, and the initial pH (pH0) from 3.0 up to 9.0 in the presence and absence of NaCl (60.0 g/L). Although the optimum pH for the photo-Fenton process is about 3.0, this particular system performed well in experimental conditions starting at alkaline and neutral pH. The results obtained here are promising for industrial applications, particularly in view of the high concentration of chloride, a known hydroxyl radical scavenger and the main oxidant present in photo-Fenton processes. © 2012 Elsevier Ltd. Source

Ferreira D.D.,Federal University of Lavras | Nagata E.A.,Federal University of Lavras | Ferreira S.C.,Federal University of Itajuba | De Seixas J.M.,Federal University of Rio de Janeiro | And 4 more authors.
Electric Power Systems Research | Year: 2014

This paper presents a new application of independent component analysis for harmonic component extraction from power system signals (voltage and current). The harmonics to be extracted can be time varying and the method does not require synchronous sampling, which means it is able to work in off-nominal frequency. The proposed method has shown to be simple in the operational stage. The method was tested using both simulated and real signals, and performance was evaluated using measures in both frequency and time domains. Results were compared with another method available in the literature. © 2014 Elsevier B.V. Source

Luna A.J.,National Institute of Industrial Property | Nascimento C.A.O.,University of Sao Paulo | Foletto E.L.,Federal University of Santa Maria | Moraes J.E.F.,Federal University of Sao Paulo | Chiavone-Filho O.,Federal University of Rio Grande do Norte
Environmental Technology (United Kingdom) | Year: 2014

In this work, a saline aqueous solution of phenol, 2,4- dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP) was treated by the photo-Fenton process in a falling-film solar reactor. The influence of the parameters such as initial pH (5-7), initial concentration of Fe 2+ (1-2.5 mM) and rate of H2O2 addition (1.87-3.74 mmol min-1) was investigated. The efficiency of photodegradation was determined from the removal of dissolved organic carbon (DOC), described by the species degradation of phenol, 2,4-D and 2,4-DCP. Response surface methodology was employed to assess the effects of the variables investigated, i.e. [Fe2+], [H2O2] and pH, in the photo-Fenton process with solar irradiation. The results reveal that the variables initial concentration of Fe2+ and H2O 2 presents predominant effect on pollutants degradation in terms of DOC removal, while pH showed no influence. Under the most adequate experimental conditions, about 85% DOC removal was obtained in 180 min by using a reaction system employed here, and total removal of phenol, 2,4- and 2,4-DCP mixture in about 30 min. © 2013 Taylor & Francis. Source

Seelig B.H.T.,National Institute of Industrial Property | De Souza L.J.,Federal University of Maranhao | Prada R.B.,Pontifical Catholic University of Rio de Janeiro
International Transactions on Electrical Energy Systems | Year: 2015

This paper presents a method to determine whether an operative voltage control action will have the steady-state expected effect or not. Sensitivity indexes are designed to correlate the controlled voltage with the controlling physical variable in generators, synchronous and static compensators, LTCs and shunt capacitors/reactors. An illustrative numerical example is provided as well as a real life one. The heavily loaded Brazilian system was operating without any problem. However, a small increase in generation caused voltage control devices to work unexpectedly. A harmful interaction among nearby control devices was also noticed. © 2015 John Wiley & Sons, Ltd. Source

Cordeiro S.Z.,Federal University of Rio de Janeiro | Simas N.K.,Federal University of Rio de Janeiro | Henriques A.B.,Federal University of Rio de Janeiro | Lage C.L.S.,National Institute of Industrial Property | Sato A.,State University of Rio de Janeiro
In Vitro Cellular and Developmental Biology - Plant | Year: 2012

A protocol was developed for micropropagation of Mandevilla moricandiana (A. DC.) Woodson, a native plant from Brazil. Shoots, obtained from in vitro plantlets were used as source of nodal segments for shoot production from axillary buds. The nodal segments were grown on Murashige and Skoog medium supplemented with different concentrations of 6-benzyladenine and/or indole-3-acetic acid to induce axillary bud elongation. After a 2-mo culture period, the medium supplemented with 1. 0 mg L-1 6-benzyladenine gave the largest number of nodal segments per explant. The nodal segments obtained from plants developed under these conditions were grown on medium supplemented with different concentrations indole-3-acetic acid, α-naphthaleneacetic acid, and indole-3-butyric acid. The use of the medium supplemented with indole-3-acetic acid and indole-3-buryric induced shoot elongation and shoot development, formation of basal callus, and/or indirect organogenesis of roots. Following transfer of shoots to soil, the plants with only basal callus showed 10% survival and developed roots from callus, while in vitro-rooted plants had a maximum 40% survival rate ex vitro. Regardless of the auxin added to the rooting medium, the acclimatization period allowed the plants rooted in vitro to develop their shoots fully. The protocol developed here is suitable for the production of shoots and rooted plantlets of M. moricandiana. © 2012 The Society for In Vitro Biology. Source

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