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Novo Hamburgo, Brazil

Bulla G.,FEEVALE | Salles A.,Federal University of Rio Grande do Sul | Vuong T.P.,CNRS Institute for Microelectronics, Electromagnetism, and Photonics: Hyperfrequency and Characterization lab
Microwave and Optical Technology Letters | Year: 2012

In this work, genetic algorithm is used to optimize the ground plane shape of planar inverted F antenna on FR-4 substrate designed for broadband applications. Novel optimized antennas were presented. A relative bandwidth about 88% was obtained with the optimized antenna. With this procedure the total bandwidth increased more than 2.5 times relatively the total bandwidth of the not optimized antenna. However, the dimensions and the cost did not increase. © 2012 Wiley Periodicals, Inc. Source

Buzzi D.C.,University of Sao Paulo | Buzzi D.C.,Federal University of Rio Grande do Sul | Viegas L.S.,Federal University of Rio Grande do Sul | Rodrigues M.A.S.,FEEVALE | And 2 more authors.
Minerals Engineering | Year: 2013

In this study, the possibility of using electrodialysis for the treatment of acid mine drainage generated from coal mining to recover water is investigated. Electrodialysis allows for the separation of anions and metallic cations, possessing the advantages of removing contaminant metals and simultaneously recovering water. To investigate this technology, the passage of anions and cations from three different acid mine drainages through a HDX 200 anion-exchange membrane and a HDX 100 cation-exchange membrane, respectively, was evaluated. The results show that electrodialysis is suitable for recovering water from acid mine drainage, with contaminant removal efficiencies that are greater than 97%. However, the precipitation of iron at the surface of the cation-exchange membrane constitutes a problem for the system by causing a blockage of the membrane through the scaling phenomenon, which reduces the process efficiency. © 2012 Elsevier Ltd. All rights reserved. Source

Kunst S.R.,Federal University of Rio Grande do Sul | Korb M.A.,Federal University of Rio Grande do Sul | Menezes T.L.,Federal University of Rio Grande do Sul | Oliveira C.T.,FEEVALE | Malfatti C.F.,Federal University of Rio Grande do Sul
Revista Escola de Minas | Year: 2013

Pre-treatment with hybrid films obtained by the sol-gel from specific alkoxide precursors has been an environmentally friendly alternative, proposed for the corrosion protection of metallic substrates, including galvanized steel. In hybrid films, inorganic compounds contribute to the increase of corrosion resistance and adhesion to the metallic substrate, while organic compounds increase the density, flexibility and functional compatibility with organic systems, such as painting. The addition of corrosion inhibitors or other compounds, to the hybrid films can modify the properties of the barrier layer, improving corrosion resistance. In this study, galvanized steel was pre-treated with a hybrid film obtained from a sol consisting of alkoxide precursors: 3 - (trimetoxisililpropil) methacrylate (TMSPMA) and tetraethoxysilane (TEOS) with the cerium nitrate addition (0.01M). The hybrid films were submitted to different curing processes: air-drying, thermal curing and ultraviolet curing. The obtained systems were characterized according to adhesion, morphology and electrochemical behavior. Besides, the degree of hydrophobicity of the systems was measured by contact angle measurements. For the accelerated corrosion tests in salt spray, the galvanized steel, pre-treated with a hybrid film, was coated with epoxidic painting. The results showed that the system using galvanized steel/hybtrid film/paint, with hybrid films cured by air -drying and ultraviolet radiation, presented the best results for corrosion resistance. Source

Buzzi D.C.,University of Sao Paulo | Viegas L.S.,Federal University of Rio Grande do Sul | Silvas F.P.C.,University of Sao Paulo | Rodrigues M.A.S.,FEEVALE | And 4 more authors.
TMS Annual Meeting | Year: 2011

One of the major impacts caused by coal mining activity is water pollution from acid mine drainage (AMD). AMD is produced by the reaction of pyrite, water and oxygen, that is intensified in the acidophilic bacteria presence. This solution acts as a leaching agent of minerals present in the residue, producing a solution with dissolved metals and sulphuric acid. Conventional treatment of AMD consists of neutralization and precipitation of heavy metals, but is technically deficient. The electrodialysis (ED) has emerged as an attractive process for effluents treatment since it does not need reagents addition and generates no waste polluting in the environment. The ED used to treat the AMD is a membrane process that consists in the separation of cations and anions by the application of an electric field on a process cell. In this study the possibility of using ED to the AMD treatment was evaluated aiming water reuse. Source

Barros P.R.M.,FEEVALE | Cazella S.C.,UFCSPA | Flores C.D.,UFCSPA
Proceedings - IEEE Symposium on Computer-Based Medical Systems | Year: 2015

With the strong growth and evolution in systems for medical education, there is an increasing concern with the quality of available software products. This article describes a methodology for evaluating software based on the NBR ISO / IEC 9126 standards and the ten golden rules for software in medical education. To validate this method, we considered as a case study the SimDeCS system. © 2015 IEEE. Source

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