University Estadual da Zona Oeste

Brazil

University Estadual da Zona Oeste

Brazil

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De Carvalho A.P.A.,University Estadual da Zona Oeste | Da Sirqueira A.S.,University Estadual da Zona Oeste
Polimeros | Year: 2016

This paper presents the mechanical, thermal and rheological properties of polymer blends of polyamide 6 (PA) and styrene-butylene-styrene (SEBS) using SEBS-g-MA as a coupling agent. The increase in the interfacial interaction of PA/SEBS blends with the addition of SEBS-g-MA was observed to enhance the mechanical properties studied (excellent elongation at break revealed by a 500%increase). Higher hardness values and a higher degree of crystallinity were obtained for compatibilized blends. In the presence of the SEBS-MA compatibilizer, the heat sweep thermograms obtained by DSC showed only one melting peak, which confirms the effect of the compatibilizer. The best rheological properties were observed for the ternary blends. The lowest concentration of SEBS-g-MA promoted the toughening of PA, and 7.5 phr of compatibilizer increased the modulus E' of the ternary blends compared to that of the binary blends. DMTA analysis allowed for the system to be characterized as partially miscible.


Leite P.R.S.,Federal University of Rio de Janeiro | Soares B.G.,Federal University of Rio de Janeiro | Sirqueira A.S.,University Estadual da Zona Oeste
Journal of Applied Polymer Science | Year: 2011

Polypropylene (PP)/styrene-butadiene rubber blends were studied with special attention given to the effects of the blend ratio and dynamic vulcanization. Dicumyl peroxide (DCP) was used as the curing agent in combination with N,N′-m-phenylene bismaleimide (BMI) as the coagent for the curing process. Outstanding mechanical performance, especially with regard to the elongation at break, and better resistance to compression set were achieved with the dynamic vulcanization; this indicated that the DCP/BMI system also acted as a compatibilizing agent. This phenomenon was also confirmed by Fourier transform infrared spectroscopy of the insoluble material, the crystallinity degree of the PP phase (as investigated by X-ray diffractometry), and scanning electron microscopy. The dynamic mechanical properties of the nonvulcanized and vulcanized blends were also investigated. The aging resistance of the blends was also evaluated. © 2010 Wiley Periodicals, Inc.


Angulo-Meza L.,Federal University of Fluminense | Soares-De Mello J.C.C.B.,Federal University of Fluminense | Gomes S.F.,University Estadual da Zona Oeste
DYNA (Colombia) | Year: 2016

Data Envelopment Analysis is a non-parametrical approach for efficiency evaluation of so-called DMUs (Decision Making Units) and takes into account multiple inputs and outputs. For each inefficient DMU, a target is provided which is constituted by the inputs or outputs levels that are to be attained for the inefficient DMU to become efficient. However, multiobjective models, known as MORO (Multiobjective Model for Ratio Optimization) provide a set of targets for inefficient DMU, which provides alternatives among which the decision-maker can choose. In this paper, we proposed an extension of the MORO models to take into account non-discretionary variables, i.e., variables that cannot be controlled. We present a numerical example to illustrate the proposed multiobjective model. We also discuss the characteristics of this model, as well as the advantages of offering a set of targets for the inefficient DMUs when there are non-discretionary variables in the data set. © The author; licensee Universidad Nacional de Colombia.


Figueiredo K.,Pontifical Catholic University of Rio de Janeiro | Figueiredo K.,University Estadual da Zona Oeste | Vellasco M.,Pontifical Catholic University of Rio de Janeiro | Pacheco M.,Pontifical Catholic University of Rio de Janeiro | de Souza F.J.,State University of Rio de Janeiro
International Journal of Innovative Computing, Information and Control | Year: 2014

This work introduces a new class of neuro-fuzzy systems for intelligent agents, called Reinforcement Learning - Hierarchical Neuro-Fuzzy System. This new class combines a hierarchical partitioning method of the input space with a Reinforcement Learning algorithm to achieve the following important characteristics: automatic creation of the model's structure; self-adjustment of the parameters; autonomous learning of the actions; capacity to deal with a greater number of inputs; and automatic generation of linguistic fuzzy rules. The proposed model was devised to overcome Imitations of traditional reinforcement learning methods based on lookup tables, particularly in applications involving continuous environments and/or environments considered to be high dimensional. The paper details the hierarchical neuro-fuzzy architecture, its basic cell, and the learning algorithm. The performance of the proposed system was evaluated in four benchmark applications the Mountain Car Problem, the Cart-Centering Problem, the Inverted Pendulum and the Khepera Robot Control. The results obtained demonstrate the capacity of the novel hierarchical neuro-fuzzy system to automatically extract knowledge from the agent's direct interaction with large and/or continuous environments. This kno wledge is in the form of fuzzy linguistic rules, with no prior definition of the number and position of the fuzzy sets. © 2014 ICIC International.


Magioli M.,Federal University of Rio de Janeiro | Soares B.G.,Federal University of Rio de Janeiro | Sirqueira A.S.,University Estadual da Zona Oeste | Rahaman M.,Indian Institute of Technology Kharagpur | Khastgir D.,Indian Institute of Technology Kharagpur
Journal of Applied Polymer Science | Year: 2012

This work investigates the effect of different preparation routes including mechanical mixing and in situ polymerization of aniline on the electromagnetic interference shielding effectiveness (EMI SE) over the X-band (8-12 GHz) frequency range for polyaniline doped with dodecylbenzene sulfonic acid (PAni.DBSA) filled in styrene-butadiene-styrene triblock copolymer matrix. The dc conductivity and dielectrical properties were also investigated. For all systems, the electrical conductivity, dielectric constant, and EMI SE increased with the increase in the concentration of PAni.DBSA. Blends prepared by the in situ polymerization exhibited higher conductivity and dielectric constant and better EMI SE characteristics than the physical blends with similar amount of PAni.DBSA. EMI SE value as high as -35 dB has been achieved with about 30% of PAni.DBSA prepared by the in situ polymerization. Regarding physical blends, those involving PAni.DBSA prepared by a redoping process displayed better EMI SE. For all systems under consideration, the conductivity and EMI SE bear an exponential relationship that can be represented by a master curve. Copyright © 2012 Wiley Periodicals, Inc.


Silva A.d.C.,Federal University of Rio de Janeiro | Senra J.D.,Federal University of Rio de Janeiro | Aguiar L.C.S.,Federal University of Rio de Janeiro | Simas A.B.C.,Federal University of Rio de Janeiro | And 3 more authors.
Tetrahedron Letters | Year: 2010

In this work, we present ligand-free Suzuki cross-coupling reactions in PEG 300 under thermal conditions at 55 °C with good yields of conversion; better results were obtained with low reaction time. In 1 hour, 1-iodo-4-nitrobenzene and phenylboronic acid reached 98% of the yield and 9700 of TON. Better results were obtained with Pd(0) sources. The reaction system was recycled up to three times with good activity. © 2010 Elsevier Ltd. All rights reserved.


Magioli M.,Federal University of Rio de Janeiro | Sirqueira A.S.,University Estadual da Zona Oeste | Soares B.G.,Federal University of Rio de Janeiro
Polymer Testing | Year: 2010

Thermoplastic elastomer blends consisting of 30% polypropylene and 70% ground rubber tire, pure or combined with virgin styrene-butadiene copolymer, were successfully prepared through a dynamic vulcanization process, involving dicumyl peroxide and N,N′-m-phenylene-bis-maleimide (BMI), in different proportions. The blends have shown excellent ultimate tensile strength and elongation at break, comparable with several others TPV systems, and also good reprocessing, which becomes useful for several potential applications. The blends were also characterized in terms of fatigue properties, morphology and dynamic mechanical properties. The tensile properties after fatigue stress decreased but this behavior was less significant for PP/GTR vulcanized blends. The effects of the dynamic vulcanization and the presence of GTR on the degree of crystallinity of the PP phase were also evaluated by differential scanning calorimetry analysis. © 2010 Elsevier Ltd. All rights reserved.


Correa M.F.,Pontifical Catholic University of Rio de Janeiro | Vellasco M.,Pontifical Catholic University of Rio de Janeiro | Figueiredo K.,Pontifical Catholic University of Rio de Janeiro | Figueiredo K.,University Estadual da Zona Oeste
Autonomous Agents and Multi-Agent Systems | Year: 2014

This paper introduces a new multi-agent model for intelligent agents, called reinforcement learning hierarchical neuro-fuzzy multi-agent system. This class of model uses a hierarchical partitioning of the input space with a reinforcement learning algorithm to overcome limitations of previous RL methods. The main contribution of the new system is to provide a flexible and generic model for multi-agent environments. The proposed generic model can be used in several applications, including competitive and cooperative problems, with the autonomous capacity to create fuzzy rules and expand their own rule structures, extracting knowledge from the direct interaction between the agents and the environment, without any use of supervised algorithms. The proposed model was tested in three different case studies, with promising results. The tests demonstrated that the developed system attained good capacity of convergence and coordination among the autonomous intelligent agents. © 2013 The Author(s).


Sotelo G.G.,Federal University of Rio de Janeiro | Dias D.H.N.,Federal University of Rio de Janeiro | MacHado O.J.,Federal University of Rio de Janeiro | David E.D.,Federal University of Rio de Janeiro | And 3 more authors.
Journal of Physics: Conference Series | Year: 2010

A Brazilian real scale magnetically levitated transport system prototype is under development at the Federal University of Rio de Janeiro. To test this system a 180 m long line has been projected and it will be concluded by the end of 2010. A superconducting linear bearing (SLB) is used to replace the wheels of a conventional train. High temperature superconductor bulks placed inside cryostats attached to the vehicle and a magnetic rail composes the SLB. To choose the magnetic rail for the test line three different rails, selected in a previous simulation work, were built and tested. They are composed by Nd-Fe-B and steel, arranged in a flux concentrator topology. The magnetic flux density for those magnetic rails was mapped. Also, the levitation force between those rails and the superconductor cryostat, for several cooling gaps, were measured to select the best rail geometry to be used in the real scale line. The SLB allows building a light vehicle with distributed load, silent and high energy efficient. The proposed vehicle is composed of four modules with just 1.5 m of length each one and it can transport up to 24 passengers. The test line having two curves with 45 m radius and a 15% acclivity ramp is also presented. © 2010 IOP Publishing Ltd.


Lopes R.M.,Instituto Oswaldo Cruz | de Salles J.B.,University Estadual da Zona Oeste | Bastos V.L.F.C.,State University of Rio de Janeiro | Bastos J.C.,State University of Rio de Janeiro
Environmental Toxicology and Chemistry | Year: 2014

The biochemical characterization of cholinesterases (ChE) from different teleost species has been a critical step in ensuring the proper use of ChE activity levels as biomarkers in environmental monitoring programs. In the present study, ChE from Oreochromis niloticus, Piaractus mesopotamicus, Leporinus macrocephalus, and Prochilodus lineatus was biochemically characterized by specific substrates and inhibitors. Moreover, muscle tissue ChE sensitivity to the organophosphate pesticide methyl-paraoxon was evaluated by determining the inhibition kinetic constants for its progressive irreversible inhibition by methyl-paraoxon as well as the 50% inhibitory concentration (IC50) for 30min for each species. The present results indicate that acetylcholinesterase (AChE) must be present in the muscle from P. mesopotamicus, L. macrocephalus, and P. lineatus and that O. niloticus possesses an atypical cholinesterase or AChE and butyrylcholinesterase (BChE). Furthermore, there is a large difference regarding the sensitivity of these enzymes to methyl-paraoxon. The determined IC50 values for 30min were 70 nM (O. niloticus), 258 nM (P. lineatus), 319 nM (L. macrocephalus), and 1578 nM (P. mesopotamicus). The results of the present study also indicate that the use of efficient methods for extracting these enzymes, their kinetic characterization, and determination of sensitivity differences between AChE and BChE to organophosphate compounds are essential for the determination of accurate ChE activity levels for environmental monitoring programs. Environ Toxicol Chem 2014;33:1331-1336. © 2014 SETAC.

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