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São José dos Campos, Brazil

Sircilli F.,Institute for Advanced Studies IEAv | Retief S.J.P.,University of Pretoria | Magalhaes L.B.,Comando Geral de Operacoes Aereas COMGAR | Ribeiro L.R.,Aeronautics and Space Institute IAE | And 4 more authors.
IEEE Transactions on Aerospace and Electronic Systems | Year: 2015

An important issue concerning numerical simulation of gas turbine-propelled aircraft in infrared scenarios (usually in military applications) is the radiometric emission properties of the aircraft exhaust plume. In this paper, a detailed description of the experimental setup and the measurement results of the infrared signature properties of a micro turbine engine plume at ground level (with an altitude of approximately 1500 m above sea level) are presented. The main instruments used were a midwave (3.6 μm) infrared camera and a spectroradiometer ( μm). The wideband emission properties were investigated with the camera as a function of the aspect angle between the camerafifs field of view and the plumefifs longitudinal axis, while maintaining a fixed engine rotational speed, as well as a function of the engine rotational speed for a fixed aspect angle of 90.. The spectral emission was investigated with the spectroradiometer as a function of three regions along the plume for a small instrument field of view and fixed engine setting. These measurements comprise the radiometric characterization of a micro gas turbine exhaust plume that, after data reduction, allows numerical modeling of this type of plume in a computer simulation. Such measurements, or the model based on it, are useful in conceptual studies regarding the infrared signatures of a turbine gas plume. It is in principle also possible to construct an infrared radiometric model of a larger-scale turbine enginefifs plume based on these characteristics. © 2015 IEEE. Source

Follador R.C.,Aeronautics Institute of Technology ITA | Follador R.C.,Institute for Advanced Studies IEAv | Trabasso L.G.,Aeronautics Institute of Technology ITA
Portland International Conference on Management of Engineering and Technology | Year: 2015

The research described herein investigated how Knowledge Management (KM), in a Brazilian Air Force (BAF) flight test environment, was impacted by the establishment of a science and technology management structure. The research was conducted initially by a bibliographic revision on the main KM theories. A documental research regarding the flight test environment KM was done and a questionnaire was submitted to identify KM characteristics previous and after the structure change. With the data obtained, the KM maturity level and the core competence in each moment were identified. Results show that both environments had the same KM maturity level. Particularly, after the structure change, it was possible to observe some development on KM processes. Both environments pointed the capability of performing flight test campaigns as its core competence. The research revealed that the structure change did not impact, in a clear way, the BAF flight test KM maturity level and, as a lesson learned, that the simple adoption of a science and technology management structure has a poor impact on knowledge management maturity level of an organization. © 2014 Portland International Conference on Management of Engineering and Technology. Source

Pariona M.M.,State University of Ponta Grossa | Teleginski V.,State University of Ponta Grossa | Dos Santos K.,State University of Ponta Grossa | De Lima A.A.O.C.,State University of Ponta Grossa | And 3 more authors.
Applied Surface Science | Year: 2013

In this research laser surface remelting without protective coating with a 2 kW Yb-fiber laser (IPG YLR-2000S) was applied in the Al-1.5 wt.%Fe alloy in order to investigate the layer treated with different techniques of superficial characterization, thereby, the technique of optical microscopy, atomic force microscopy and low-angle X-ray diffraction were used. The present work mainly focuses on the corrosion study by diverse techniques in aggressive environment of the laser-treated area and the substrate material was carried out, thereby, at open circuit potential testing, the results have shown a displacement to more anodic values in the corrosion potential for the laser-treated specimen when compared to the untreated specimen; in potentiodynamic polarization tests have shown that as a result of the laser treatment, the corrosion current can be reduced by as much as ten times, and a passive region was obtained, which served as an effective barrier for reducing anodic dissolution and finally, the result in cyclic polarization curves of the untreated sample there was a greater area of the hysteresis loop, implying that it is more susceptible to corrosion. This study was complemented by other techniques mentioned above in order to elucidate this study. Laser surface remelting process has definitely modified the surface film, which results in higher corrosion resistance, a large range of passivation and a lower area of the hysteresis loop. © 2013 Elsevier B.V. All rights reserved. Source

Pariona M.M.,State University of Ponta Grossa | Teleginski V.,State University of Ponta Grossa | Santos K.D.,State University of Ponta Grossa | Machado S.,State University of Ponta Grossa | And 3 more authors.
Surface and Coatings Technology | Year: 2012

Yb-fiber laser beam was used successfully to irradiate Al-1.5wt.% Fe alloy, modifying its surface to improve its corrosion resistance for aerospace applications. Laser-treated samples were examined by optical microscopy, scanning electron microscopy, energy dispersive X-ray diffraction (EDX), and low-angle X-ray diffraction (LA-XRD), and tested by Vickers microhardness. The alloy's corrosion resistance was tested by exposure to H 2SO 4 solution, Tafel plots, polarization, and corrosion potentials. The results reveal the formation of weld filet structures with metastable phases and finely dispersed precipitates. The creation of a finely porous layer of protective coating produced during the rapid remelting process contributed to increase the corrosion resistance of laser-treated samples when compared with untreated samples. The Yb-fiber laser beam technology applied to the surface treatment of aluminum alloys proved efficient in augmenting their corrosion resistance, thus deserving further investigation for aerospace and automotive applications. © 2011. Source

Pariona M.M.,State University of Ponta Grossa | Teleginski V.,State University of Ponta Grossa | Santos K.D.,State University of Ponta Grossa | Dos Santos E.L.R.,State University of Ponta Grossa | And 2 more authors.
Materials Characterization | Year: 2012

Laser beam welding has recently been incorporated into the fabrication process of aircraft and automobile structures. Surface roughness is an important parameter of product quality that strongly affects the performance of mechanical parts, as well as production costs. This parameter influences the mechanical properties such as fatigue behavior, corrosion resistance, creep life, etc., and other functional characteristics such as friction, wear, light reflection, heat transmission, lubrification, electrical conductivity, etc. The effects of laser surface remelting (LSR) on the morphology of Al-Fe aerospace alloys were examined before and after surface treatments, using optical microscopy (OM), scanning electron microscopy (SEM), low-angle X-ray diffraction (LA-XRD), atomic force microscopy (AFM), microhardness measurements (Vickers hardness), and cyclic voltammetry. This analysis was performed on both laser-treated and untreated sanded surfaces, revealing significant differences. The LA-XRD analysis revealed the presence of alumina, simple metals and metastable intermetallic phases, which considerably improved the microhardness of laser-remelted surfaces. The morphology produced by laser surface remelting enhanced the microstructure of the Al-Fe alloys by reducing their roughness and increasing their hardness. The treated surfaces showed passivity and stability characteristics in the electrolytic medium employed in this study. © 2012 Elsevier Inc. All rights reserved. Source

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