EVALUATION OF THE EFFECTS OF ILLUMINATION, TEMPERATURE AND PAINTING FINISH IN PSP TECHNIQUE

This paper reports the results of global pressure measurements on a NACA0012 profile, obtained with the Pressure Sensitive Paint technique (PSP), and compares them with conventional pressure tap measurements with the purpose of analyzing the influence of parameters as illumination efficiency and temperature variation of the air flow in the accuracy of the PSP experimental results. The experimental measurements were conducted in the Pilot Transonic Wind Tunnel (TTP) of the Instituto de Aeronáutica e Espaço (IAE) for Mach number values of 0.4, 0.6 and 0.8. The experiments showed that in a carefully prepared experiment, under appropriated operational conditions, and rigorous adjustments of the PSP components, the obtained results can be accurate. Moreover, even when the influence of temperature is significant and the illumination condition is not ideal, it was possible to estimate well the impact caused in the pressure distribution over the model surface

Three-dimensional spatial solitons in CS2

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Near-infrared Kerr nonlinearity of Pb(PO3)2–WO3 glasses

We report measurements of the nonlinear refractive index, n 2 , and the nonlinear absorption coefficient, α 2 , of Pb ( PO 3 ) 2 – WO 3 glasses. The measurements were performed using 100 fs (17 ps) laser pulses at 800 nm (1064 nm). Positive values of n 2 ∼ 10 − 19 m 2 / W and negligible α 2 were measured. The results show that the nonlinearity is faster than 100 fs and it is observed an increase of n 2 with the increasing of the WO 3 amount in the samples. The Boling, Glass, and Owyoung model, based on the semiclassical harmonic oscillator model, was used to predict the values of n 2 , with basis on the values of the linear refractive index of the samples

The effect of hydrogen on the fracture toughness of friction-stir welded API 5L X70 pipeline steels

The hydrogen embrittlement (HE) leads to severe steel degradation of mechanical properties. The hydrogen atoms diffuse into the steel and get posi- tioned into reversible and irreversible trap sites. The pipe to transport oil and gas needs to be welded to construct long-distance pipeline projects; thus, friction-stir welding (FSW) has proven an excellent alternative to joining these pipelines. Therefore, this work assessed and analyzed the influence of hydro- gen on the microstructure and fracture toughness of API 5L X70 steel welded by friction-stir welding. The in-service conditions were simulated by charging the specimen electrolytically in a 3.5% NaCl water solution with an intensity current of 2 mA cm 2 . According to fracture toughness tests, the base metal (BM) was more affected by hydrogen embrittlement than the friction-stir zone (SZ), with a fracture toughness reduction of 20% after hydrogen charging. The SZ fracture toughness did not statistically show changes in hydrogen charging by the used times; however, the fracture mechanism changed from ductile to brittle-like after 4 days of charging. The SZ depicted a better fracture toughness than BM due to the bainitic microstructure, a significant amount of irrevers- ible hydrogen trapping.The authors acknowledge the National Council for Scientific and Technological Development scholarship, CNPq - Brazil, grant number: 165065/2017-6. This research used facilities of the Brazilian Nanotechnology National Laboratory (LNNano), part of the Brazilian Centre for Research in Energy and Materials (CNPEM), a private non-profit organization under the supervision of the Brazilian Ministry for Science, Technology, and Innovations (MCTI). In addition, the author would like to thank the staff at the University of S ̃ao Paulo, specifi- cally in the Materials Engineering Department at the S ̃ao Carlos School of Engineering (SMM, EESC-USP), the Laboratory for Friction and Wear Technology (LTAD) at F I G U R E 1 3 Orientation maps showing the crack path at the stable crack propagation region during the CTOD test. (A, B) H-free samples from the BM and SZ and (C, D) H-charged samples from BM and SZ [Colour figure can be viewed at wileyonlinelibrary.com] 12 GIAROLA ET AL . the Federal University of Uberlândia (UFU), and the Multi-user Laboratory Complex (C-LABMU) ate the State University of Ponta Grossa (UEPG). The authors also acknowledge Gabriel Severino de Almeida for the sample preparation. H.C. Pinto is a CNPq fellow. J. A. Avila is a Serra Hunter Fellow and a CNPq fellow.Peer ReviewedPostprint (published version

Robust Two-Dimensional Spatial Solitons in Liquid Carbon Disulfide

The excitation of near-infrared ð2 þ 1ÞD solitons in liquid carbon disulfide is demonstrated due to the simultaneous contribution of the third- and fifth-order susceptibilities. Solitons propagating free from diffraction for more than 10 Rayleigh lengths although damped, were observed to support the proposed soliton behavior. Numerical calculations using a nonlinear Schro ̈dinger-type equation were also performed

Near‐infrared dissipative three‐dimensional spatial solitons in CS2

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Picosecond third-order nonlinearity of lead-oxide glasses in the infrared

Heavy metal-oxide glasses containing lead and bismuth were prepared, and their picosecond third-order nonlinear (NL) optical characteristics were investigated. NL refractive indices of ≈ 10−18 m2/W at 1064 nm were measured. Negligible NL absorption was verified and, as a consequence, the samples present a good factor-of-merit for photonic applications