Measurement of scaling laws for shock waves in thermal nonlocal media

We are able to detect the details of spatial optical collisionless wave-breaking through the high aperture imaging of a beam suffering shock in a fluorescent nonlinear nonlocal thermal medium. This allows us to directly measure how nonlocality and nonlinearity affect the point of shock formation and compare results with numerical simulations.Comment: 4 pages, 4 figure

Cryogenic Technology Development for Exploration Missions

This paper reports the status and findings of different cryogenic technology research projects in support of the President s Vision for Space Exploration. The exploration systems architecture study is reviewed for cryogenic fluid management needs. It is shown that the exploration architecture is reliant on the cryogenic propellants of liquid hydrogen, liquid oxygen and liquid methane. Needs identified include: the key technologies of liquid acquisition devices, passive thermal and pressure control, low gravity mass gauging, prototype pressure vessel demonstration, active thermal control; as well as feed system testing, and Cryogenic Fluid Management integrated system demonstration. Then five NASA technology projects are reviewed to show how these needs are being addressed by technology research. Projects reviewed include: In-Space Cryogenic Propellant Depot; Experimentation for the Maturation of Deep Space Cryogenic Refueling Technology; Cryogenic Propellant Operations Demonstrator; Zero Boil-Off Technology Experiment; and Propulsion and Cryogenic Advanced Development. Advances are found in the areas of liquid acquisition of liquid oxygen, mass gauging of liquid oxygen via radio frequency techniques, computational modeling of thermal and pressure control, broad area cooling thermal control strategies, flight experiments for resolving low gravity issues of cryogenic fluid management. Promising results are also seen for Joule-Thomson pressure control devices in liquid oxygen and liquid methane and liquid acquisition of methane, although these findings are still preliminary

Effects of different tooth bleaching systems on the roughness and superficial morphology of enamel and a restorative composite resin

Objetivo: Avaliar as alterações de rugosidade e morfologia superficial do esmalte e da resina composta após diferentes técnicas de clareamento dental. Material e método: incisivos bovinos íntegros foram selecionados, sendo que cavidades padronizadas foram confeccionadas na face vestibular, as quais foram restauradas com resina composta. Os dentes foram distribuídos em grupos, de acordo com o tratamento proposto: G1-clareamento com peróxido de carbamida (PC) 10%; G2 - clareamento com peróxido de hidrogênio (PH) a 38%; G3- clareamento com PH a 38% associado à foto-ativação com LED. Para G1, o agente clareador foi aplicado por 8 horas diárias durante 21 dias. Para\ud G2 e G3, foram realizadas 3 sessões de clareamento, caracterizadas por 3 aplicações do gel clareador por 15 minutos, com intervalos de 7 dias entre as sessões, sendo que em G3 o gel clareador foi ativado com LED (470nm) por 6 minutos. As superfícies do esmalte e da resina composta foram avaliadas antes e após o procedimento clareador através de um rugosímetro e de um microscópio de força atômica. Resultados: Os resultados demonstraram diferença significante da rugosidade do esmalte antes e após o clareamento apenas para G1, em relação ao controle (Wilcoxon, p<0,05). Para a resina composta, nenhum dos grupos apresentou diferença estatística em relação ao controle (Mann-Whitney, p>0,05). Conclusão: O aumento da rugosidade do esmalte aconteceu apenas quando o clareamento foi realizado através da aplicação de um gel com 10% de PC. Nenhum dos procedimentos clareadores avaliados nesta pesquisa interferiram na rugosidade e morfologia da resina composta.CNPq (135181/2010-0; 30129/2010-1

Studying a Masonry Sail Vault by Antonio da Sangallo the Elder in the Fortezza Vecchia in Livorno

The present contribution aims to illustrate some first results obtained from ongoing research on a 16th-century masonry sail vault in the Fortezza Vecchia (the Old Fortress) in Livorno (Italy). A multidisciplinary research is currently ongoing. The information collected by means of geometric surveys and experimental tests are being used as input data for the different analytical and numerical models expressly developed to study the vault’s structural response. The structural analysis has been performed using two analytical models set within the framework of limit analysis. The first considers the vault as a thin shell, and suitable sets of statically admissible stresses are built; the second model is a modern reinterpretation of Durand-Claye’s method for domes. As an additional term of comparison, numerical analyses are carried out by means of FE models. The study is still under development, and a first set of results has been obtained by limiting the analysis to vertical loads accounting for the self-weight of the vault and that of the overlying soil layer

Simple optical apparatus for trepanning and percussion microdrilling using pulsed green Nd:YAG laser

Laser microdrilling is becoming an important tool in a wide spectrum of industrial applications due to the possibility to produce microholes in almost any type of materials. The purpose of this study was to create a simple and efficient optical apparatus that could produce microdrillings by either percussion or trepanning methods. The developed system is composed by a nanosecond Nd:YAG laser operating at 532 nm and one convergent lens with off-center optical axis of 1′. For the trepanning method the lens spins in its geometrical center at constant angular speed of 350 rpm. Typical microholes diameters obtained in metallic aluminum were in the range of 22 to 95 μm and 70 to 150 μm for the percussion and trepanning methods, respectively. Typical drilling velocities were in the order of 10 μm/s for applied fluences ranging from 22 to 150 J/cm2 for both methods. The values of the ratio between input and output diameters were 0.30 and 0.25 for microholes obtained by percussion and trepanning methods, respectively. The best microholes morphology was obtained using the trepanning method. The results for both methods are discussed based on the optical and thermal properties of the material processed and the constructed apparatusFAPESPCNP

Landsat-7 ETM+ Radiometric Calibration Status

Now in its 17th year of operation, the Enhanced Thematic Mapper + (ETM+), on board the Landsat-7 satellite, continues to systematically acquire imagery of the Earth to add to the 40+ year archive of Landsat data. Characterization of the ETM+ on-orbit radiometric performance has been on-going since its launch in 1999. The radiometric calibration of the reflective bands is still monitored using on-board calibration devices, though the Pseudo-Invariant Calibration Sites (PICS) method has proven to be an effect tool as well. The calibration gains were updated in April 2013 based primarily on PICS results, which corrected for a change of as much as -0.2%/year degradation in the worst case bands. A new comparison with the SADE database of PICS results indicates no additional degradation in the updated calibration. PICS data are still being tracked though the recent trends are not well understood. The thermal band calibration was updated last in October 2013 based on a continued calibration effort by NASA/Jet Propulsion Lab and Rochester Institute of Technology. The update accounted for a 0.31 W/sq m/ sr/micron bias error. The updated lifetime trend is now stable to within + 0.4K

Zoneamento agroclimático para o cultivo do feijão da "seca" em Goiás.

O presente trabalho tem por objetivo definir as regiões e os períodos mais apropriados ao cultivo do feijão da "seca" no Estado de Goiás.bitstream/CNPAF/16689/1/doc_94.pd

Raman and infrared phonon features in a designed cubic polymorph of CaTa2O6

At room temperature, calcium tantalite (CaTa2O6) is known to exhibit three stable polymorphs, depending on the crystal growth conditions. In this work, the laser-heated pedestal growth method was used to obtain CaTa2O6 single crystal fibers in its quenched (ordered) cubic polymorph, attractive for optical applications. X-ray diffraction, Raman scattering and infrared spectroscopy showed that the fibers grew into the centrosymmetrical Pm3 space group. The growth axis was determined as [001]. The cylindrical fibers (20 mm long and 400 μm wide) showed good optical quality, without cracks or striations, but with small facets, parallel to crystal edges or to in-plane edge bicetrices. A comprehensive set of the optical phonons for this cubic structure was obtained, consisting of 13 (of 16 foreseen) triply degenerate polar phonons, and all the 21 predicted Raman modes. By using special scattering geometries, the Raman bands were attributed to their corresponding irreducible representations. In general, the phonons showed rather large damping constants, which do not compromise the designed optical applications in compact lasers but increase the losses in the microwave range, even though the dielectric response is quite adequate for microwave applications. Quenched defects and crystal polymorphism can be at the origin of the large phonon damping.CNPqFINEPFAPEMIGFAPES

3D objective quality assessment of light field video frames

With the rapid advances in light field displays and cameras, research in light field content creation, visualization, coding and quality assessment is now beyond a state of emergence; it has already emerged and started attracting a significant part of the scientific community. The capability of light field displays to offer glasses-free 3D experience simultaneously for multiple users has opened new avenues in subjective and objective quality assessment of light field image content, and video is also becoming research target of such quality evaluation methods. Yet it needs to be stated that while static light field contents have evidently received relatively more attention, the research on light field video content still remains largely unexplored. In this paper, we present results of the objective quality assessment of key frames extracted from light field video content. To this end, we use our own full-reference 3D objective quality metric

Growth and magnetic properties of bulk electron doped 'LA IND. 0.7''CE IND. 0.3''MN''O IND. 3' manganites

We report on the growth of bulk samples (composite fibers) of the nominal composition La0.7Ce0.3MnO3 (LCMO) manganites (with Curie temperature TC,max = 300 K) by using the laser heated pedestal growth (LHPG) technique. Samples composition was verified through scanning electron microscopy with energy dispersive X-ray (EDX) analysis. The magnetic behavior of the fibers was probed by magnetization measurements. In addition to a weak ferromagnetic transition at TC0 = 45 K (due to MnO2 impurities), two more transitions with TC1 = 126 K and TC2 = 180 K were identified and linked to regions with cerium concentration of x = 0.063 and 0.13, respectively.FAPESPCAPESCNP