On the resonant behavior of the16O+15N reaction

The ¹⁶ O+ ¹⁵ N reaction products have been studied by the γ-ray detection method in the CM energy range 15.5 to 36.1 MeV and by the kinematical coincidence method at energies ranging from E _CM =20.6 to 33.5MeV. The γ-ray yield excitation function of the ¹⁶O 3^? inelastic channel shows the existence of resonant structures. Two structures with ～ 1.6 MeV width are observed in the large angle elastic scattering excitation function, they are correlated with the resonances seen in the inelastic channel. Angular momentum assignments were made from the elastic backward angular distributions.     

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Hydroxylation of Aromatics by H2O2 Catalyzed by Mononuclear Non-heme Iron Complexes: Role of Triazole Hemilability in Substrate-Induced Bifurcation of the H2O2 Activation Mechanism

Rieske dioxygenases are metalloenzymes capable of achieving cis-dihydroxylation of aromatics under mild conditions using O₂ and a source of electrons. The intermediate responsible for this reactivity is proposed to be a cis-Fe^V(O)(OH) moiety. Molecular models allow the generation of a Fe^III(OOH) species with H₂O₂, to yield a Fe^V(O)(OH) species with tetradentate ligands, or {Fe^IV(O); OH^.} pairs with pentadentate ones. We have designed a new pentadentate ligand, mtL₄², bearing a labile triazole, to generate an “in-between” situation. Two iron complexes, [(mtL₄²)FeCl](PF₆) and [(mtL₄²)Fe(OTf)₂]), were obtained and their reactivity towards aromatic substrates was studied in the presence of H₂O₂. Spectroscopic and kinetic studies reflect that triazole is bound at the Fe^II state, but decoordinates in the Fe^III(OOH). The resulting [(mtL₄²)Fe^III(OOH)(MeCN)]²⁺ then lies on a bifurcated decay pathway (end-on homolytic vs. side-on heterolytic) depending on the addition of aromatic substrate: in the absence of substrate, it is proposed to follow a side-on pathway leading to a putative (N₄)Fe^V(O)(OH), while in the presence of aromatics it switches to an end-on homolytic pathway yielding a {(N₅)Fe^IV(O); OH^.} reactive species, through recoordination of triazole. This switch significantly impacts the reaction regioselectivity.     

Determination of the chloride and fluoride contents in the ebrie lagoon and the underground waters in ivory Coast by means of X-ray fluorescence analysis and potentiometric method

This study is devoted to the determination of percentages of fluoride and chloride in Ebrié located in Abidjan and wells located in the central and southern areas of Ivory Coast. Nondispersive X-Ray Fluorescence method and potentometric method with ion sensitive electrodes have been used. For underground water, the concentrations obtained are, with the exception of some isolated cases, lower than the upper limits tolerated for drinking water. These waters are drinkable. In a lagunal environment, the results show that the elements drawn from the bottom of the sea, through the Vridi Canal, spread in the lagoon. The ratio of the concentration of elements and the corresponding salinity confirm the fact that chloride undergoes an essential dilution in the lagoon due to contact with continental waters. A semi-diurnal periodicity of the concentration of elements has been firmly established. This period is the same as the tidal one.     

Fusion-fission in the35Cl +12C reaction at Elab=180 MeV

The properties of the two-body channels populated in the³⁵Cl +¹²C reaction, at a bombarding energy of 180 KeV, have been studied by means of a kinematical coincidence technique. Binary reaction products show full energy equilibration and isotropic angular distributions in the center-of-mass frame. The asymmetrical elemental distribution of the fully-damped yields, similar to that observed previously in the³²S +²⁴Mg reaction, suggests the occurence of fusion-fission rather than orbiting.     

Reinvestigation of the234Pa gamma-ray spectrum

The decay of²³⁴Pa(UZ) was reinvestigated using high-resolution coaxial and planar HPGe detectors. Accurate energy and intensity values of 327 photons are given, of which 144 previously unobserved.     

Reevaluation of the half-lives of87mSr,90mY and109mPd

The half-lives of^87mSr,^90mY and^109mPd have been determined more accurately, as compared to previous measurements.     

Stability analysis of a polymer film casting problem

The polymer cast film process consists of stretching a molten polymer film between a flat die and a drawing roll. Drawing instabilities are often encountered and represent a drastic limitation to the process. Newtonian fluid film stretching stability is investigated using two numerical strategies. The first one is a ‘tracking’ method, which consists of solving Stokes equations in the whole fluid area (extrusion die and stretching path) by finite elements. The interface is determined to satisfy a kinematic equation. A domain decomposition meshing technique is used in order to account for a flow singularity resulting from the change in the boundary conditions between the die flow region and the stretching path region. A linear stability method is then applied to this transient kinematic equation in order to investigate the stability of the stationary solution. The second method is a direct finite element simulation in an extended area including the fluid and the surrounding air. The time‐dependent interface is captured by solving an appropriate level‐set function. The agreement between the two methods is fair. The influence of the stretching parameters (Draw ratio and drawing length) is investigated. For a long stretching distance, a critical Draw ratio around 20 delimitating stable and unstable drawing conditions is obtained, and this agrees well with the standard membrane models, which have been developed 40 years ago. When decreasing the stretching distance, the membrane model is no longer valid. The 2D models presented here point out a significant increase of the critical Draw ratio, and this is consistent with experimental results. Copyright © 2015 John Wiley & Sons, Ltd.     

Precision measurements of the half-lives of60mCo,79mSe,104mRh,149Nd,176mLu,177Lu and198Au

Carrier-free^99mTcO₄ ^– eluated from clinical⁹⁹Mo/^99mTc generators was examined to determine its specific activity. The observed specific activity was found to be always lower than the calculated value based on the⁹⁹Mo–^99mTc–⁹⁹Tc decay scheme data. These results could be explained in terms of existence of excess Tc loaded onto generator column.