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Morschbacher E.F.,Companhia Paranaense de Energia Copel | Marengoni N.G.,West Parana State University | Albuquerque D.M.,State University of Maringa
Bioscience Journal

The prebiotics are classified as monosaccharides, oligosaccharides or polysaccharides and can be defined as non-digestible natural additives by enzymes that beneficially affect the host by stimulating the microbial action. The Bio-Mos® is a prebiotic obtained from the cell wall of yeast (Saccharomyces cerevisiae) and in its constitution are α- mannans, β-glycans and glycoproteins. This study aimed to evaluate the effect of adding of prebiotic mannanoligosaccharides (Bio-Mos®) in the diet during the sexual reversion to larvae of Nile tilapia on zootechnical performance, sex ratio, uniformity of lots and chemical composition of carcass. One-thousand and eighty larvae with three days old and initial average weight of 10.9 ± 1.2 mg were used. The larvae were distributed in 36 aquaria with 30 L, in a completely randomized experimental design with six replications and treatments (0.0, 0.2, 0.4, 0.6, 0.8 and 1% for inclusion of prebiotic). The ad libitum feeding was carried out six times a day with diet isonutritive, isocaloric, and 60 mg kg kg-1 of hormone masculine 17-α-methyltestosterone. At the end of the reversion, the values of final average weight, length, survival, specific growth and condition factor were 620 mg, 32.62 mm, 91.85%, 13.34% day-1 and 1.31, respectively, and did not show significantly differences (p>0.05). The effectiveness of sex reversal was 100% and there was not difference (p>0.05) in uniformity of lots and in chemical composition of fish fed with different levels of inclusion of prebiotic in the diet. The inclusion up to 1.0% Bio-Mos® do not harm the zootechnical performance, sex ratio, survival, uniformity of lots and chemical composition of carcass of Nile tilapia during the sexual reversion. Source

Kanieski M.R.,Federal University of Parana | Santos T.L.,Federal University of Parana | Neto J.G.,Companhia Paranaense de Energia Copel | Souza T.,Federal University of Parana | And 2 more authors.
Floresta e Ambiente

The purpose of this study was to evaluate the influence of meteorological variables in the growth of forest trees in an area of Ombrophylous Floodplain Forest belonging to REPAR in Araucaria, State of Parana. The sample comprised 20 plots of 10 m × 10 m plots. In order to follow the timing and rate of growth of the main tree species, from July 2009 to July 2010, the selected individuals received dendrometric bands. The meteorological data were obtained from the meteorological station of Curitiba, provided by SIMEPAR. The meteorological data and the growth of each species were compared using Pearson's correlation. The species showed different behavior according to sociological position and the fact of being native or exotic. The weather variable that most influenced the growth of the species was temperature, with a positive correlation to Hovenia dulcis and Sebastiania commersoniana, for individuals in the canopy; and to Ligustrum lucidum, Myrrhinium loranthoides and Sebastiania commersoniana, for individuals in the understory. Source

Lima J.M.,Companhia Paranaense de Energia Copel | Lourenco E.M.,Federal University of Parana | Schilling M.T.,Federal University of Fluminense
Controle y Automacao

The Brazilian power grid has been traditionally designed and operated using a set of deterministic reliability criteria. This method has played an important role in the design and operation of the Brazilian bulk power system for decades. However, deterministic criterions tend to use available resources less optimally and stress facilities in the context of transmissions capacity. In the expansion planning, for instance, the main deterministic criterion is the well know n-1. With regard to the approval of scheduled maintenance of transmission equipment on the basic grid, the Brazilian Independent System Operator (ISO) is the n-2. This criterion requires that the electrical system support the unavailability of any particular transmission element that has been deactivated for maintenance purposes, as well as any other contingency situations that may arise, without violating any system constraints. This paper discusses the limitations of the deterministic reliability criteria and proposes a new approach entirely based on probabilistic techniques. The new method allows a more efficient scheduled maintenance during medium load workdays, without significantly increasing the risk level of the system. The expected result of implementing this new criterion is a reduction in operations and maintenance costs, which should in turn reduce the electricity rates paid by end users. Source

Rosas G.B.,Companhia Paranaense de Energia Copel | Lourenco E.M.,Federal University of Parana | Fernandes T.S.P.,Federal University of Parana
Controle y Automacao

This paper proposes an extension of the Optimal Power Flow (OPF) formulation so that networks can be modeled at physical level. Differently from the conventional formulation, based on the bus-branch model of the network, the proposed extension allows the explicitly representation of switches and circuit breakers of selected substations. The proposed methodology is based on the zero impedance branch representation in the power system state estimation, which has been recently applied to the power flow problem. In this approach, the active and reactive power flow through switches and circuit breakers are included as new state variables. Furthermore, the devices' statuses are included as new equality constraints in the OPF problem. The impact of the new network representation in the solution of the OPF, as well as the application of the proposed tool are presented and discussed in the paper. Simulation results related to the IEEE 30bus test system and a real power system of COPEL (Parana Energy Company), with 291 buses, are presented to illustrate and evaluate the performance of the proposed approach. Source

Bissacot A.C.G.,Federal University of Itajuba | Salgado S.A.B.,Federal University of Itajuba | Balestrassi P.P.,Federal University of Itajuba | Paiva A.P.,Federal University of Itajuba | And 2 more authors.
Open Electrical and Electronic Engineering Journal

In this work, we evaluate the probability of falling metal structures from transmission lines. It is our objective to extract knowledge about which variables influence the mechanical behavior of the operating lines and can be used to diagnose potential falling towers. Those pieces of information can become a basis for directing the investments of reinforcement structures, avoiding the occurrence of long turn offs and high costs as a consequence of damage to towers of transmission lines. The results are obtained using the history of 181 metal structures currently in operation in the state of Paraná/Brazil. For the classification of transmission lines susceptible to failures it is proposed to identify the most likely lines considering the following parameters: operating voltage, wind and relief of the region, air masses, temperature, land type, mechanical capacity, function and foundation structure. The classic technique of classifying binary events used in this type of problem is the logistic regression (LR). The more recent technique for classification, using Artificial Neural Networks (ANN) can also be applied. The results are compared through the area under receiver operating characteristics (ROC) curves. © Bissacot et al.; Licensee Bentham Open. Source

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