Institution
National Nuclear Energy Commission
Government•Rio de Janeiro, Brazil•
About: National Nuclear Energy Commission is a government organization based out in Rio de Janeiro, Brazil. It is known for research contribution in the topics: Dosimetry & Laser. The organization has 3816 authors who have published 4694 publications receiving 59951 citations.
Topics: Dosimetry, Laser, Neutron, Corrosion, Monte Carlo method
Papers published on a yearly basis
Papers
More filters
••
TL;DR: In this paper, a survey on past nuclear merchant ships experience is provided, which provides some information on history, architectures and hints of reasons for the success or failures of each project.
25 citations
••
TL;DR: In this paper, the effect of collective couplings to the excited states of the target has been studied by means of coupled-channels calculations, using a doublefolding potential for the bare interaction between the colliding nuclei, supplemented with a phenomenological imaginary part of Woods-Saxon type.
Abstract: New data for the $^{6}\mathrm{He}+^{9}\mathrm{Be}$ reaction at ${E}_{\mathrm{lab}}=16.2$ and 21.3 MeV have been taken and analyzed. The effect of the collective couplings to the excited states of the target has been studied by means of coupled-channels calculations, using a double-folding potential for the bare interaction between the colliding nuclei, supplemented with a phenomenological imaginary part of Woods-Saxon type. In addition, three- and four-body continuum-discretized coupled-channels calculations have been performed to investigate the effect of the projectile breakup on the elastic scattering. Both effects, the coupling to target and projectile excited states, are found to affect significantly the elastic scattering. The trivial local polarization potential extracted from the continuum-discretized coupled-channels calculations indicates that continuum couplings produce a repulsive real part and a long-range imaginary part in the projectile-target interaction.
25 citations
••
TL;DR: The average multiplicities of charged plus neutral pions produced in e + e − collisions have been determined for total center-of-mass energies ranging from 1.2 to 2.4 GeV as discussed by the authors.
25 citations
••
TL;DR: In this article, the V. Fischeri test was used to characterize DCF toxicity in the absence and presence of fluoxetine (FLX), prior and after irradiation.
Abstract: Water contamination by the anti-inflammatory drug diclofenac (DCF) is a consequence of its incomplete removal in wastewater and sewage treatment plants, which is potentialized by interactions with other pharmaceutical contaminants. In this context, electron beam irradiation (EBI) has been considered a clean technology for degrading pharmaceutical compounds in water. Nevertheless, the identification of DCF by-products and their correlation with biological recalcitrance and acute toxicity are poorly understood. In this study, the V. fischeri test was used to characterize DCF toxicity in the absence and presence of fluoxetine (FLX), prior and after irradiation. The results showed complete DCF degradation at low dose (5 kGy). DCF concentration followed pseudo first-order decay with respect to the absorbed, with k0 = (1.33 ± 0.10) kGy−1 (DCF) and k0 = (0.90 ± 0.12) kGy−1 (DCF + FLX). In contrast, negligible TOC removal was observed even at 7.5 kGy, with the formation of recalcitrant, non-biodegradable by-products, as also suggested by the respirometry test. Despite that, the toxicity of the DCF solution diminished from (19.6 ± 1.6) TU to (6.2 ± 2.3) TU, and from (6.8 ± 0.9) TU to (3.1 ± 0.2) TU, in the absence and presence of FLX, respectively, after irradiation up to 5 kGy. Four of the eleven by-products identified by direct-injection MS were easily degraded by EBI, and one (C13H14ClNO5) was considered the least recalcitrant but the most toxic. Based on these results, a possible DCF degradation pathway is proposed, involving hydroxylation and oxidation of aromatic rings, dehalogenation and C − N bond cleavage.
25 citations
••
TL;DR: X-ray diffraction showed that both laser irradiations promoted formation of α-tricalcium phosphate and tetracalcium phosphate, and a significant increase on the crystal growth of the enamel apatite, which can explain the improved resistance of enamel to demineralization observed in the second part of the study.
Abstract: This study investigated the compositional and crystallographic changes on enamel when irradiated by Er,Cr:YSGG (λ=2.7μm, 8.5J/cm2) or Nd:YAG (λ=1064nm, 84.9J/cm2 associated with black coating), its resistance to demineralization when irradiation is associated with fluoride (APF-gel), and CaF2-like material formation and retention. Sample surfaces were analyzed by ATR-FTIR (4000-650cm-1, 4cm-1) resolution. Irradiation with Er,Cr:YSGG laser promoted a significant decrease on carbonate content of enamel. After
Nd:YAG irradiation, it was observed a significant decrease of carbonate and amides I and II. X-ray diffraction showed that both laser irradiations promoted formation of α-tricalcium phosphate and tetracalcium phosphate, and a significant increase on the crystal growth of the enamel apatite (ANOVA, p<0.05 was used for all analysis). These changes can explain the improved resistance of enamel to demineralization observed in the second part of the study, in which 240 enamel slices were divided in 8 groups, received 4 min of professional fluoride gel (APF-gel 1.23%F-) applied before or after irradiation. After treatments, the formation of calcium fluoride (CaF2) was determined. The remaining slabs of each group were submitted to a 10-day pH-cycling
model and, subsequently, enamel demineralization was evaluated by cross-sectional microhardness. Both lasers significantly reduced enamel demineralization (ANOVA, p<0.05), and the previous APF-gel application followed by laser showed the higher reduction of enamel demineralization. CaF2 formed before pH-cycling was
significantly higher in groups were APF was associated with laser irradiation. After demineralization, these groups also presented higher CaF2 retention in respect to isolated treatments (only APF or only laser), suggesting its anticaries potential.
25 citations
Authors
Showing all 3838 results
Name | H-index | Papers | Citations |
---|---|---|---|
Giorgio Parisi | 108 | 941 | 60746 |
Sergio Ferrara | 105 | 726 | 44507 |
Richard Wilson | 70 | 809 | 21477 |
Eliana B. Souto | 66 | 447 | 15706 |
Andrea Saltelli | 65 | 184 | 31540 |
Fausto Croce | 51 | 162 | 11753 |
Sílvia M. Rocha | 42 | 163 | 4934 |
Marcos Duarte | 41 | 122 | 5855 |
Luiz Gustavo Cançado | 41 | 106 | 13155 |
Ruggero Caminiti | 41 | 267 | 7296 |
Francesco Romanelli | 40 | 236 | 5756 |
Mario Molinaro | 39 | 111 | 5923 |
Giovanna Cenacchi | 38 | 217 | 4948 |
Claudio Pellegrini | 38 | 235 | 5885 |
Maria Manuela Silva | 37 | 324 | 5258 |