On the dynamics of bubbles in boiling water

We investigate the dynamics of many interacting bubbles in boiling water by using a laser scattering experiment. Specifically, we analyze the temporal variations of a laser intensity signal which passed through a sample of boiling water. Our empirical results indicate that the return interval distribution of the laser signal does not follow an exponential distribution; contrariwise, a heavy-tailed distribution has been found. Additionally, we compare the experimental results with those obtained from a minimalist phenomenological model, finding a good agreement.Comment: Accepted for publication in Chaos, Solitons & Fractal

Sm3+ Effects In The Tm3+ Doped Tellurite Glass For S-band Amplification

Thulium doped Samarium codoped tellurite-tungstate glasses were produced. Luminescence properties in the infrared region were investigated looking to observe improved properties for S-band amplification in the co doped samples. Thulium is well-known by the 3H4-3F4 radiative transition emitting around ∼1.47μm, which is a self-terminating transition in tellurite hosts due the longer lifetime of the lower level in relation to the upper level of this transition. Analysis of absorption and emission spectra showed that we could quench the 3F4 level significantly, what improved the intensity of the emission at 1.49μm. However, the state 3H4 were also quenched due the cross relaxation process due the absorption bands of Sm3+ around 1.5μm. © 2013 Copyright SPIE.8601The Society of Photo-Optical Instrumentation Engineers (SPIE),NKT Photonics A/S,Fianium Ltd.,PolarOnyx, Inc.Zhang, G.-Q., Zhang, G.-Q., Yang, Q.-F., Cheng, S.-Q., Zhou, T., Evolution of the Internet and its cores (2008) New Journal of Physics, 10 (12), p. 123027. , doi:10.1088/1367-2630/10/12/123027Thomas, G., Shraiman, B., Glodis, P., Stephens, M., Towards the clarity limit in optical fibre (2000) Nature, 404 (6775), pp. 262-264. , doi:10.1038/35005034Tanabe, S., (2001) Properties of Tm3+ Doped Tellurite Glasses for 1.4 Um Amplifier, pp. 85-92Zhou, B., Lin, H., Pun, E.Y.-B., Tm3+-doped tellurite glasses for fiber amplifiers in broadband optical communication at 1.20 μm wavelength region (2010) Optics Express, 18 (18), pp. 18805-18810Liu, X., Chen, B.J., Pun, E.Y.B., Lin, H., Ultra-broadband near-infrared emission in praseodymium ion doped germanium tellurite glasses for optical fiber amplifier operating at E-, S-, C-, and L-band (2012) Journal of Applied Physics, 111 (11), p. 116101. , doi:10.1063/1.4722997Peng, M., Qiu, J., Chen, D., Meng, X., Yang, I., Jiang, X., Zhu, C., Bismuth- and aluminum-codoped germanium oxide glasses for super-broadband optical amplification (2004) Optics Letters, 29 (17), pp. 1998-2000Peng, M., Dong, G., Wondraczek, L., Zhang, L., Zhang, N., Qiu, J., Discussion on the origin of NIR emission from Bi-doped materials (2011) Journal of Non-Crystalline Solids, 357 (11-13), pp. 2241-2245. , Elsevier B.V. doi:10.1016/j.jnoncrysol.2010.11.086Allen, R., Esterowitz, L., An Efficient 1.46 um Thulium Fiber Laser via a Cascade Process (1993) Journal of Quantum Eletronics Letters, 29 (2), pp. 303-306Shen, S., Jha, A., Zhang, E., Wilson, S., Tm3+-Ho3+ and Tm3+-Tb3+ energy transfer in tellurite glass (2007) Journal of Luminescence, 126 (2), pp. 434-440. , doi:10.1016/j.jlumin.2006.08.092Tanabe, S., Properties of Tm3+-doped tellurite glasses for 1.4um amplifier (2001) Proceedings of SPIE, 4282, pp. 85-92Chillcce, E.F., Barbosa, L.C., Cruz, C.H.B., Tellurite photonic crystal fiber made by a stack-and-draw technique (2006) Journal of Non-Crystalline Solids, 352, pp. 3423-3428. , doi:10.1016/j.jnoncrysol.2006.02.12

Recent advances in lanthanide spectroscopy in Brazil

This review discusses recent advances in lanthanide spectroscopy involving luminescence applications Q2 carried out in Brazil. The revised topics include glasses, sol–gel, light-emitting diodes, nanoparticles, metal–organic frameworks, coordination polymers, thin films, energy transfer processes, upconversion and development of new theoretical tools. The important role played by Prof. Oscar L. Malta on this subject is evidenced by his many contributions to the broad range of investigations reported here and this review is dedicated to him, on the occasion of his 60th birthday

Spectroscopic Investigation Of The Glass System Teo2-wo3-na2o-nb2o5 For Mid-infrared Amplifiers

Tellurite glasses following the molar concentration 71.5% TeO2, 22.5% WO3, 5% Na2O and 1.5% Nb2O5 have been investigated. Samples doped with Tm2O3, Pr2O3, Yb2O3 or Bi2O3 were fabricated by the conventional melt quenching process. Rare-earth (RE) 3+ ions have well defined emission bands. On the other hand, Bismuth emission in the infrared region have been found in some glasses and even that emission laser have been already obtained, the mechanism behind its luminescence is still misunderstood[1]. The Bismuth emission is sometimes referred as a "superbroadband" emission around 1.3um, which is very promising for an optical amplifier, but, to the best of our knowledge a bismuth based optical amplifier have not been produced yet. Our purpose is to investigate the mechanism behind this misunderstood "superbroadband" luminescence, and compare it with the rare-earths properties in the same range. The characterization consists in measurements of optical absorption spectra, optical emission spectra and life-time decay. Differential thermal analysis (DTA) was also performed, to identify changes in Tg and Tx as function of the doping concentration, which is important to the drawing process of a fiber. © 2013 Copyright SPIE.8601The Society of Photo-Optical Instrumentation Engineers (SPIE),NKT Photonics A/S,Fianium Ltd.,PolarOnyx, Inc.Bufetov, I.A., Dianov, E.M., Bi-doped fiber lasers (2009) Laser Physics Letters, 6 (7), pp. 487-504. , doi:10.1002/lapl.200910025Wei, Y.Q., Harsh, A., Penty, R.V., White, I.H., Shen, S., Jha, A., (2008) Er/Ce Codoped Tellurite Fibre Amplifier for High-Gain and Low-Noise Operation, pp. 1-3Peng, M., Dong, G., Wondraczek, L., Zhang, L., Zhang, N., Qiu, J., Discussion on the origin of NIR emission from Bi-doped materials (2011) Journal of Non-Crystalline Solids, 357 (11-13), pp. 2241-2245. , Elsevier B.V. [doi:10.1016/j.jnoncrysol.2010.11.086]Tanabe, S., Properties of Tm3+-doped tellurite glasses for 1.4um amplifier (2001) Proceedings of SPIE, 4282, pp. 85-92Taylor, E.R.M., Ng, L.N., Nilsson, J., Caponi, R., Pagano, A., Potenza, M., Sordo, B., Thulium-Doped Tellurite Fiber Amplifier (2004) IEEE Photonics Technology Letters, 16 (3), pp. 777-779. , doi:10.1109/LPT.2004.823733Zhou, D., Wang, R., Yang, Z., Song, Z., Yin, Z., Qiu, J., Spectroscopic properties of Tm3+ doped TeO2-R2O-La2O3 glasses for 1.47μm optical amplifiers (2011) Journal of Non-Crystalline Solids, 357 (11-13), pp. 2409-2412. , Elsevier B.V. [doi:10.1016/j.jnoncrysol.2010.12.027]Shen, S., Jha, A., Zhang, E., Wilson, S., Tm3+-Ho3+ and Tm3+-Tb3+ energy transfer in tellurite glass (2007) Journal of Luminescence, 126 (2), pp. 434-440. , doi:10.1016/j.jlumin.2006.08.092Ohishi, Y., Kanamori, T., Kitagawa, T., Takahashi, S., Snitzer, E., Sigel, G.H., Pr(3+)-doped fluoride fiber amplifier operating at 1.31 microm (1991) Optics Letters, 16 (22), pp. 1747-1749Zhou, B., Pun, E.Y., (2011) Superbroadband Near-IR Emission from Praseodymium-doped Bismuth Gallate Glasses, pp. 2958-2960Zhou, B., Tao, L., Tsang, Y.H., Jin, W., Pun, E.Y.-B., Superbroadband near-IR photoluminescence from Pr3+-doped fluorotellurite glasses (2012) Optics Express, 20 (4), pp. 3803-3813Liu, X., Chen, B.J., Pun, E.Y.B., Lin, H., Ultra-broadband near-infrared emission in praseodymium ion doped germanium tellurite glasses for optical fiber amplifier operating at E-, S-, C-, and L-band (2012) Journal of Applied Physics, 111 (11), p. 116101. , doi:10.1063/1.4722997Chillcce, E.F., Barbosa, L.C., Cruz, C.H.B., Tellurite photonic crystal fiber made by a stack-and-draw technique (2006) Journal of Non-Crystalline Solids, 352, pp. 3423-3428. , doi:10.1016/j.jnoncrysol.2006.02.127Jiang, C., Gan, F., Zhang, J., Deng, P., Huang, G., (1999) Yb: Tellurite Laser Glass with High Emission Cross-section, pp. 209-214Guyot, Y., Steimacher, A., Medina, A.N., Baesso, M.L., Lima, S.M., Andrade, L.H.C., Brenier, A., Boulon, G., Spectroscopic properties, concentration quenching, and laser investigations of Yb3+-doped calcium aluminosilicate glasses (2011) October, 28 (10), pp. 2510-251

As relações Brasil-EUA na transição presidencial Truman-Eisenhower: Imagens do jornal "Última Hora" (1952-1953)

Este artigo tem por objetivo analisar as imagens construídas pelo jornal Última Hora sobre as relações Brasil-Estados Unidos, no período de transição entre os governos dos presidentes Harry Truman e Dwight Eisenhower. Por meio da análise das edições do periódico publicadas entre 1952 e 1953, investigamos as expectativas, frustrações e conflitos de interesse que deram o tom das relações entre ambos os países em pleno momento de acirramento das tensões no cenário internacional da Guerra Fria. Entendendo o UH como instrumento legitimador das posturas de Vargas, trilhamos pela via da imaginação política, observando estratégias de condicionamento da opinião pública a respeito de pontos nevrálgicos nas relações Brasil-EUA à época, como a cooperação econômica, política e militar

Near-IR emission in Pr(3+)single doped and tunable near-IR emission in Pr3+/Yb3+ codoped tellurite tungstate glasses for broadband optical amplifiers

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPA study of the broadband near-infrared emission in Pr3+ single doped and Pr3+/Yb3+ codoped tellurite-tungstate glasses for optical amplification is presented. In the Pr3+ single doped samples pumped at 474 nm the emission band at 1480 nm presents a FWHM of similar to 140 nm. The Yb3+ addition produces a FWHM broadening up to 155 nm, achieved through the (1)G(4)-H-3(5) transition. The emission spectra when the codoped sample is pumped at 980 nm shows efficient energy transfer from Yb3+ to Pr3+ resulting in an intense Pr3+ emission around 1330 nm. This shows that changing the pump wavelength it is possible to select the D-1(2)-(1)G(4) or the (1)G(4)-H-3(5) transition, displacing the emission band from similar to 1480 to similar to 1330 nm. (C) 2014 Elsevier B.V. All rights reserved.A study of the broadband near-infrared emission in Pr3+ single doped and Pr3+/Yb3+ codoped tellurite-tungstate glasses for optical amplification is presented. In the Pr3+ single doped samples pumped at 474 nm the emission band at 1480 nm presents a FWHM of similar to 140 nm. The Yb3+ addition produces a FWHM broadening up to 155 nm, achieved through the (1)G(4)-H-3(5) transition. The emission spectra when the codoped sample is pumped at 980 nm shows efficient energy transfer from Yb3+ to Pr3+ resulting in an intense Pr3+ emission around 1330 nm. This shows that changing the pump wavelength it is possible to select the D-1(2)-(1)G(4) or the (1)G(4)-H-3(5) transition, displacing the emission band from similar to 1480 to similar to 1330 nm.36610201026CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCNPq [574017/2008]FAPESP [2005/51689-2, 2008/57857-2, 2012/04291-7, 2009/54066-7]574017/20082005/51689-2; 2008/ 57857-2; 2009/54066-7; 2012/04291-7The Authors would like to thank CNPq (INCT/FOTONICOM, grant 574017/2008) and FAPESP (grants 2005/51689-2, 2008/57857-2 and 2012/04291-7) for their financial support; to the "Laboratorio multiusuario de espectroscopia optica avancada" (LMEOA) for the loan of the spectrofluorimeter (FAPESP grant 2009/54066-7); to professor Antonio Medina Neto and Dr. Leandro Herculano for help in some lifetime measurements performed at "Universidade Estadual de Maringa"; and to the professor Hugo Fragnito for the helpful discussions

Pulsed‐Laser Excited Thermal Lens Spectroscopy With Sample‐Fluid Heat Coupling

Analytical and finite element analysis modeling methods of the pulsed-laser excited photothermal (PT) lens signal of solids samples surrounded by air are presented. The analytical and finite element analysissolutions for the temperatures induced in the sample and in the air were found to agree over the range of conditions in this report. Model results show that the air contribution to the total PT lens signal is significant in many cases. In fact, these solutions open up the possibility of applying the pulsed excited thermal lens method for accurate prediction of the heat transfer to the coupling fluid and subsequently to study the gas surrounding the samples by using a known material solid sample

Effect of enzymatic pretreatment and increasing the organic loading rate of lipid-rich wastewater treated in a hybrid UASB reactor

This study aimed at evaluating the effect of increasing organic loading rates and of enzyme pretreatment on the stability and efficiency of a hybrid upflow anaerobic sludge blanket reactor (UASBh) treating dairy effluent. The UASBh was submitted to the following average organic loading rates (OLR) 0.98 Kg.m(-3).d(-1), 4.58 Kg.m(-3).d(-1), 8.89 Kg.m(-3).d(-1) and 15.73 Kg.m(-3).d(-1), and with the higher value, the reactor was fed with effluent with and without an enzymatic pretreatment to hydrolyze fats. The hydraulic detention time was 24 h, and the temperature was 30 +/- 2 degrees C. The reactor was equipped with a superior foam bed and showed good efficiency and stability until an OLR of 8.89 Kg.m(-3).d(-1). The foam bed was efficient for solid retention and residual volatile acid concentration consumption. The enzymatic pretreatment did not contribute to the process stability, propitiating loss in both biomass and system efficiency. Specific methanogenic activity tests indicated the presence of inhibition after the sludge had been submitted to the pretreated effluent It was concluded that continuous exposure to the hydrolysis products or to the enzyme caused a dramatic drop in the efficiency and stability of the process, and the single exposure of the biomass to this condition did not inhibit methane formation. (C) 2011 Elsevier B.V. All rights reserved