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Federal University of Technology - Parana is a public university with campuses in twelve cities of the Brazilian state of Paraná. Wikipedia.

Frigori R.B.,Federal Technological University of Parana
Nuclear Physics B | Year: 2010

We compute the spectrum of gluonic screening-masses in the 0++ channel of quenched 3. d Yang-Mills theory near the phase-transition. Our finite-temperature lattice simulations are performed at scaling region, using state-of-art techniques for thermalization and spectroscopy, which allows for thorough data extrapolations to thermodynamic limit. Ratios among mass-excitations with the same quantum numbers on the gauge theory, 2. d Ising and λφ4 models are compared, resulting in a nice agreement with predictions from universality. In addition, a gauge-to-scalar mapping, previously employed to fit QCD Green's functions at deep IR, is verified to dynamically describe these universal spectroscopic patterns. © 2010 Elsevier B.V.

Conceicao P.C.,Federal Technological University of Parana | Dieckow J.,Federal University of Parana | Bayer C.,Federal University of Rio Grande do Sul
Soil and Tillage Research | Year: 2013

Increases in carbon (C) input and stabilization are key processes to turn soils into sinks of atmospheric CO2-C and help mitigating global warming. We hypothesized (i) that C sequestration in no-tillage soil is further enhanced by high input cropping systems and (ii) that the sequestered C is stored mainly in the mineral associated fraction. The objective of this study was to assess, in 2003, the C sequestration and stabilization in a subtropical Acrisol (Eldorado do Sul, Brazil) subjected to 18-year conventional tillage [CT] and no-tillage [NT] combined with two cropping systems: black oat (Avena strigosa Schreb) as winter cover crop - maize (Zea mays L.) as summer grain crop [Ot/M]; and black oat plus vetch (Vicia villosa Roth) as winter cover crops - maize in summer intercropped with cowpea (Vigna unguiculata (L.) Walp) cover crop [Ot+V/M+C]. Soil C stock in the 0-20cm layer was higher in NT than in CT, either in Ot/M (31.1 vs. 27.8Mgha-1, P<0.05) or Ot+V/M+C (37.3 vs. 32.8Mgha-1, P<0.05). Annual C sequestration rate in NT relative to CT was 0.25Mgha-1 in Ot+V/M+C and 0.18Mgha-1 in Ot/M, in agreement to the higher biomass-C addition and legume cover crops inclusion in Ot+V/M+C (7.6 vs 4.0Mgha-1 year-1) and to our first hypothesis. Increase in the proportion of large macroaggregates (9.51-4.76mm) and of mean weight diameter occurred in NT soil up to 10cm depth, both in Ot/M and Ot+V/M+C. In NT, most of the C accumulation relative to CT occurred in the mineral-associated fraction, showing the importance of organo-mineral interaction in C stabilization and supporting our second hypothesis. However, the physical protection by aggregates played equally important role by stabilizing the occluded particulate organic matter (occluded-POM) before it was further stabilized by organo-mineral interaction. No-tillage is recommended as a sustainable soil management, but to increase soil C accumulation, the potential of cropping systems such those based on legume cover crops must be concurrently explored. © 2013 Elsevier B.V.

Salvatierra R.V.,Federal University of Parana | Oliveira M.M.,Federal Technological University of Parana | Zarbin A.J.G.,Federal University of Parana
Chemistry of Materials | Year: 2010

In this work, we report for the first time, the synthesis of several carbon nanotube (CNT)/polyaniline (PANI) nanocomposites obtained through interfacial polymerization, in which the resulting material is obtained directly as a transparent and freestanding film at the water-toluene interface. The films are obtained spontaneously with high stability and can be easily transferred with high optical quality to any kind of substrate or directly to a desirable device. Samples containing several CNT/PANI ratios have been prepared. The characterization of the resulting materials was carried out by FT-IR, UV-vis-NIR, and Raman spectroscopy, X-ray diffraction, cyclic voltammetry, scanning and transmission electron microscopy, and conductivity measurements. The results indicate that the polymerization of aniline starts at the carbon nanotube walls, resulting in polymer-coated CNTs. A π-π interaction between the CNTs and the PANI is proposed. The formation of the self-standing films is discussed in terms of the stabilization of the water-toluene interface. © 2010 American Chemical Society.

Doff A.,Federal Technological University of Parana
European Physical Journal C | Year: 2016

It is quite possible that the technicolor problems are related to the poorly known self-energy expression, or the way chiral symmetry breaking (CSB) is realized in non-abelian gauge theories. Actually, the only known laboratory to test the CSB mechanism is QCD. The TC dynamics may be quite different from the QCD, this fact has led to the walking TC proposal making the new strong interaction almost conformal and changing appreciably its dynamical behavior. There are different ways to obtain extreme walking (or quasi-conformal) technicolor theories, in this paper we propose a scheme to obtain this behavior based on an extension of the electroweak sector of the standard model, in the context of so-called 331-TC model. © 2016, The Author(s).

De Souza V.H.R.,Federal University of Parana | Oliveira M.M.,Federal Technological University of Parana | Zarbin A.J.G.,Federal University of Parana
Journal of Power Sources | Year: 2014

The present work describes for the first time the synthesis and characterization of single wall carbon nanotubes/polyaniline (SWNTs/PAni) nanocomposite thin films in a liquid-liquid interface, as well as the subsequent construction of a flexible all-solid supercapacitor. Different SWNTs/PAni nanocomposites were prepared by varying the ratio of SWNT to aniline, and the samples were characterized by scanning and transmission electron microscopy, Raman and UV-Vis spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The pseudo-capacitive behavior of the nanocomposites was evaluated by charge/discharge galvanostatic measurements. The presence of the SWNTs affected the electronic and vibrational properties of the polyaniline and also improved the pseudo-capacitive behavior of the conducting polymer. A very thin and flexible all-solid device was manufactured using two electrodes (polyethylene terephthalate-PET covered with the SWNT/PAni nanocomposite separated by a H2SO4-PVA gel electrolyte). The pseudo-capacitive behavior was characterized by a volumetric specific capacitance of approximately 76.7 F cm-3, even under mechanical deformation, indicating that this nanocomposite has considerable potential for application in new-generation energy storage devices. © 2014 Elsevier B.V. All rights reserved.

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