Ammonia borane-based reactive mixture for trapping and converting carbon dioxide

Ammonia borane (NH₃BH₃) is a reducing agent, able to trap and convert carbon dioxide. In the present work, we used a reactive solid consisting of a mixture of 90 wt.% of NH₃BH₃ and 10 wt.% of palladium chloride, because the mixture reacts in a fast and exothermic way while releasing H₂ and generating catalytic Pd⁰. We took advantage of such reactivity to trap and convert CO₂ (7 bar), knowing besides that Pd⁰ is a CO₂ hydrogenation catalyst. The operation (i.e. stage 1) was effective: BNH polymers, and B−O, C=O, C−O, and C−H bonds (like in BOCH₃ and BOOCH groups) were identified. We then (in stage 2) pyrolyzed the as-obtained solid at 1250 °C and washed it with water. In doing so, we isolated cyclotriboric acid H₃B₃O₆ (stemming from B₂O₃ formed at 1250 °C), hexagonal boron nitride, and graphitic carbon. In conclusion, the stage 1 showed that CO₂ can be ‘trapped’ and converted, resulting in the formation of BOCH₃ and BOOCH groups (possible sources of methanol and formic acid), and the stage 2 showed that CO₂ transforms into graphitic carbon.     

Antimicrobial and nuclease activity of mixed polypyridyl ruthenium(II) complexes

The ruthenium(II) complexes with 2,9-dimethyl-1,10-phenanthroline (dmphen) and terpyridine derivatives have been synthesized and screened for their antimicrobial potency. The interaction of these complexes with Herring Sperm DNA was investigated by thermal denaturation, viscosity measurements, gel electrophoresis and spectrophotometric methods. The results indicate that the complexes bound to DNA via partial intercalative mode. The salt-dependent binding of these complexes has been determined by UV–Vis spectrophotometric titration. The contribution of the non-electrostatic binding free energy (ΔG_t^o) to the total binding free energy change (ΔG^o) is found to be ~ 88% at [Na⁺] = 0.075 M. The large value suggests that the stabilization of the DNA binding is mostly due to the contribution of non-electrostatic process.     

Platinum-based Alloys as oxygen–reduction Catalysts for Solid–Polymer–Electrolyte Direct Methanol Fuel Cells

Electrocatalytic activities of various carbon-supported platinum-based binary, namely, Pt–Co/C, Pt–Cr/C and Pt–Ni/C, and ternary, namely, Pt–Co–Cr/C and Pt–Co–Ni/C, alloy catalysts towards oxygen reduction in solid–polymer–electrolyte direct methanol fuel cells were investigated at 70°C and 90°C both at ambient and 2bar oxygen pressures. It was found that Pt–Co/C exhibits superior activity relative to Pt/C and other alloy catalysts.     

Significance of toxaphene in Great Lakes fish consumption advisories

Fish consumption advisories have been issued for the Great Lakes generally based on the most restrictive contaminant. For the Canadian waters of the Great Lakes, toxaphene causes minor restrictions only in Lake Superior, i.e., 3% of the total (restrictive + unrestrictive) advisories issued. However, the significance of the hazard posed by toxaphene in fish is not clear since more restrictive advisories due to other priority contaminants may be masking the less restrictive advisories. We simulated fish consumption advisories for the Toxaphene-only scenario by neglecting the presence of contaminants other than toxaphene, and compared with the issued advisories as well as with the published simulated Mercury-only scenario. Restrictive advisories under the Toxaphene-only scenario compared to the issued toxaphene related advisories would increase from 3% to 14%, < 1% to 4%, and 0% to 2% for Lakes Superior, Huron and Ontario, respectively, and remain at 0% for Lake Erie. For Lake Superior, most of the restrictive Toxaphene-only advisories would be for fatty fish. Overall, the Toxaphene-only advisories would be significantly less restrictive compared to the issued advisories, and also generally less restrictive compared to the Mercury-only scenario. These results suggest that toxaphene is less of a concern than PCBs (including dioxin-like PCBs), dioxins–furans and mercury from the perspective of health risk to humans consuming Great Lakes fish; elevated toxaphene is mainly a concern for human consumers of Lake Superior fatty fish. Our results suggest that the routine monitoring of toxaphene in other Canadian waters of the Great Lakes and Lake Superior lean/pan fish could be discontinued.     

Fast video shot retrieval based on trace geometry matching

Content-based video retrieval technology holds the key to the efficient management and sharing of video content from different sources, in different scales, across different platforms, and over different communication channels. In this work, fast video shot retrieval algorithms, based on the geometry of video sequence traces in the principal component space, are presented. Techniques to address scale (spatial and temporal) issues, in addition to noise and other possible distortions, such as frame dropping, are discussed. Experimental results demonstrate the effectiveness of the proposed approach.     

Ionic Liquids Assisted Synthesis of ZnO Nanostructures:Controlled Size,Morphology and Antibacterial Properties

Systematic analysis about the exploitation of imidazolium based ionic liquids（ILs）,[BMIM]BF₄[IL1],[EMIM]BF₄ [IL2]and[BMIM]PF₆[IL3]as the morphological template on the basic sol-gel method adopted synthesis of nanostructured zinc oxide（ZnO） is presented.X-ray diffraction（XRD）,particle size analysis（PSA） and scanning electron microscopy（SEM） have been employed for the characterization of structure and morphology of the synthesized ZnO particles.Well-defined capsule like shaped morphology with lower nanosize is observed for the ZnO nanoparticles with IL1 than those with IL2 and IL3.This confirms that IL1 served as an effective templating material due to their unique properties.Especially the effective aggregation of ZnO particles with a self-organized frame of IL1 was the essential factor to produce the lower nanosized ZnO with capsule shaped structure.The synthesized ZnO samples with IL2 and IL3 fabricated the flake like shaped and rod like shaped morphologies in the range of nanoscale.The formed ZnO nanoparticles with IL2 exhibit higher nanosize than the ZnO nanoparticles produced by IL1,owing to shorter length of alkyl group in its cation which restricts steric effect and permits the nanoparticles to grow longer.Even though IL3 produced the discrete ZnO nanorods,the hydrophobic nature of IL3 created the higher nanosize than the ZnO nanoparticles formed by other two ionic liquids.Antibacterial properties of the synthesized ZnO nanostructures were investigated against Staphylococcus aureus（gram positive） and Escherichia coli（gram negative） bacteria by Agar diffusion test method.Microbial experiments indicate that the synthesized ZnO samples show a wide spectrum of antimicrobial activities and performed better against S.aureus than E.coli with the same concentration of ZnO.     

Fatigue strength prediction of ultra high strength steel butt‐welded joints

First, fatigue tests were performed on butt‐welded joints made of novel direct quenched ultra high strength steel with high quality welds. Two different welding processes were used: MAG and Pulsed MAG. The weld profiles, misalignments and residual stresses were measured, and the material properties of the heat‐affected zone were determined. Fatigue tests were carried out with constant amplitude tensile loading both for joints in as‐welded condition and for joints after ultrasonic peening treatment. Finally, in fatigue strength predictions, the crack initiation phase was estimated using the procedures described by Lawrence et al. [Lawrence F V, Ho N J and Mazumdar P K (1981) Predicting the fatigue resistance of welds. Annu. Rev. Mater. Sci, 11, 401–425]. The propagation phase was simply estimated using S–N curves for normal quality butt welds, which may contain pre‐existing cracks or crack‐like defects eliminating the crack initiation stage.