Synthesis of water-soluble polymers containing sulfonic acid and amine moieties for the recovery of metal ions using ultrafiltration

Copolymers from 2-acrylamido-2-methyl-propane sulfonic acid (APSA) and N-acryloyl-N-methyl piperazine (AP) were synthesized by radical polymerization with ammonium peroxydisulfate as the initiator. The copolymerization yield ranged between 93 and 95%. The copolymers were completely water soluble, and were characterized by FTIR and NMR spectroscopy. The copolymer composition was determined from elemental analysis through the S/C ratio. The binding capacity for metal ion was studied by the LPR technique at different pH and filtration factors. The retention depended strongly on the pH and on the copolymer composition. With increasing pH and increasing content of APSA units in the copolymer, the metal ion retention increased. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 22–30, 2001     

Elements of comparison between different inert matrix fuels as regards plutonium utilisation and safety coefficients

The current international trend is to focus towards the utilization of plutonium. The use of composite fuels in inert matrix (U-free) is a potentially efficient solution to this problem. This document deals with the cermet fuels, selected for their excellent behaviour under irradiation and their high thermal conductivity. The emphasis is placed on the study of kinetic coefficients. Comparisons are performed with other solutions that use other composite fuels, especially the Solid Solutions and ROXs. As core control requires a heterogeneous assembly, an assembly whose characteristics are compared to the APA reference is proposed.     

Rye secalin characterisation and use to improve zein-based film performance

Rye prolamins (secalin) were extracted, characterised and used as biopolymer source to produce plasticised films, as well as composite films in the presence of corn zein. Secalin film showed lower contact angle values and higher moisture content, solubility and swelling index than zein film, whereas the water vapour permeability of the two films was not different. Also, secalin film exhibited lower tensile strength and Young’s modulus and higher elongation at break. The average functional properties of the secalin/zein blend were morphologically confirmed by SEM analysis of the composite film surface that showed a good miscibility and compatibility of the two different biopolymers. These results indicated that secalin films were less hydrophobic and more flexible than those previously prepared by using other prolamins, whereas a material with hydrophobic features similar to those of zein films and a flexibility comparable to that exhibited by secalin films was obtained by preparing a secalin/zein blend.     

Structural characterization of malachite-like coprecipitated precursors of the binary CuO-ZnO catalysts: bulk and surface properties

Copper and zinc hydroxycarbonates with Cu/Zn atomic ratios of 100/0, 92/8, 85/15, 77/23, 67/33 and 50/50 were prepared by coprecipitation at constant pH. The samples with higher Cu/Zn ratios are monophasic with malachite structure, whereas the richer zinc samples contain, in addition to malachite, the aurichalcite phase, whose concentration is very low in the 77/23 specimen but increases with zinc content. The cell volume of the zincian-malachite phase decreases up to 30% of zinc content. This result is related, as also shown by DTA measurements, to an increasing stability of compounds richer in zinc, to increasing covalent effects and/or to less octahedral site distortion around the metal atoms when zinc substitutes Cu²⁺ ions in the malachite structure. XPS investigations have shown that both in the monophasic and biphasic samples the surface Cu/Zn atomic ratios are nearly equal to those found by chemical analysis, so indicating that an homogeneous dispersion of zinc in the solid solutions and a good interdispersion of the zincian-malachite and aurichalcite phases are both achieved. A comparative study of the photoelectron and X-ray excited Auger transitions of Cu and Zn gives also support for an increasing covalency of the chemical bonds in zincian-malachites with respect to pure malachite. Moreover, the analysis of the initial state effect on the full width half maximum of the Cu(2p_3/2) and of the Zn(2p_3/2) peaks gives evidence that zinc substitutes copper in the less octahedrally distorted (type-II) metal site of the malachite structure.     

A Spin Resonance Investigation of Magnetism and Dynamics in the Charge-transfer Salts β"-(BEDT-TTF)4[(H3O)M(C2O4)3]S

We report a spin resonance study of the family of quasi-two-dimensional organic (super)conductors β”-(BEDT-TTF)₄[(H₃O)M(C₂O₄)₃]S, where M is a 3d transition metal ion and S is a host solvent molecule. The spin systems for M = Cr³⁺ (S = 3/2) and M = Fe³⁺ (S = 5/2) are investigated by means of both resonant and field modulation techniques in the frequency range between 50 and 313 GHz. The role of the different solvent molecules in determining the degree of spin-orbit coupling and the local symmetry at the metal ion site is established. The low temperature behaviour of intensities, positions and widths of the resonant lines shows significant modifications of the spin-orbit coupling, and of the inter-and intra-ionic spin-spin inter actions. Despite the onset of a weak antiferromagnetic internal field at low temperature, the ultimate narrowing of the lines suggests spin-lattice interactions may still be the dominant relaxation process. Diamagnetic screening in the mixed state of the superconducting samples for fields parallel to the quasi-two-dimensional layers induces additional lineshifts only below B = 2.5T and T = 4K, determining the threshold of full field penetration within the anion layers.     

Eicosanoids and fat emulsions in acute respiratory distress syndrome patients

Laparoscopic splenectomy has been accepted as a feasible extension of minimally invasive surgery, which has undergone dramatic improvements in both technology and instrumentation. We performed a laparoscopic splenectomy in a 7-year-old girl with hereditary spherocytosis. The patient recovered rapidly and returned to unrestricted activities quickly. The appropriate positioning of each laparoscopic port is essential for a good operative view and smooth access. It is also important to dissect the hilum of the spleen meticulously. Laparoscopic splenectomy in the pediatric age group appears to be another promising extension of laparoscopic surgery.     

The catalytic activity of Cu-ZSM-5 and Cu-Y zeolites in NO decomposition: dependence on copper concentration

NO decomposition was studied on Cu-ZSM-5 (Cu exchange extent from 23 to 210%) and Cu-Y (Cu exchange extent from 5 to 105%) catalysts at 773 K. The results show that the activity (NO molecules decomposed per gram of catalyst per second) increases by roughly 100-fold when the extent of exchange with copper in the ZSM-5 framework increases from 80 to 100%. This behaviour shows that not all Cu sites are equivalent in their decomposition activity. Cu-ZSM-5 samples prepared with either H-ZSM-5 or Na-ZSM-5 show the same activity pattern.