PEG–PLA hydrogels were prepared by stereocomplexation of poly(lactide) (PLA) blocks of opposite chirality. Gelation occurred upon mixing aqueous solutions of both enantiomers of PEG6500–(PLA)2, PEG12500–(PLA)2 and PEG21800–(PLA)8 block copolymers. Stereocomplexed hydrogels from PEG6500–(PLA)2 polymers were found to be stable up to ~37 8C, while those from PEG12500–(PLA)2 and PEG21800–(PLA)8 blo...

In recent years, nanostructured Au catalysts have attracted a lot of attention as potential candidates for the removal of poisonous carbon monoxide from synthesis gas streams, thus upgrading hydrogen gas to be used as fuel at the anode of lowtemperature fuel cells. The interest in Au nanoparticles has been motivated by the pioneering work of Haruta et al., who demonstrated the extremely high ac...

The effect of the addition of porcelain fired scraps on the sintering, phase composition and properties of a hard porcelain was studied. Two ceramics were compared: a commercial triaxial porcelain labelled C-0 and one, where 15% of the mass of C-0 was substituted by scraps yielding a composition labelled C-15. The sintering was evaluated by the linear shrinkage, the water absorption and the var...

Monophasic oxides of the formula, Ba!_xPbxTiO3 (0 < x < 1:0) were obtained at temperatures close to 500 8C from polymeric precursors formed using citric acid and ethylene glycol. These oxides were found to be tetragonal for all values of x, the distortion increasing with Pb content. Differential scanning calorimetry (DSC) shows that the decomposition of the precursor to the oxides varies with c...

Since the first report of ultraviolet lasing from ZnO nanowires, substantial effort has been devoted to the development of synthetic methodologies for one-dimensional ZnO nanostructures. Among the various techniques described in the literature, evaporation and condensation processes are favored for their simplicity and high-quality products, but these gas-phase approaches generally require econ...

We report here on the high activity and stability of low-content gold–cerium oxide catalysts for the water–gas shift reaction (WGS). These catalysts are reversible in cyclic reduction–oxidation treatment up to 400 8C, are non-pyrophoric, and are thus potential candidates for application to hydrogen generation for fuel cell power production. Low-content (0.2–0.9 at.%) gold–ceria samples were pre...

Reaction-induced changes of the morphology of a Pt foil catalyst during ammonia oxidation were investigated in a temperature-controlled way for partial pressures of oxygen and ammonia around 4.5 and 3 kPa, respectively, and at temperatures between 20 and 700 8C. The presence of the feed mixture (ammonia and oxygen) was required to induce surface roughening. Moreover, the reaction temperature co...

Injected sandstones occurring in the Kimmeridgian of NE Scotland along the bounding Great Glen and Helmsdale faults formed when basinal fluids moved upward along the fault zones, fluidizing Oxfordian sands encountered at shallow depth and injecting them into overlying Kimmeridgian strata. The orientation of dykes, in addition to coeval faults and fractures, was controlled by a stress state rela...

The macroscopic load-bearing capability of a composite is directly related to the strain partitioning due to load transfer between the component phases. Using neutron diffraction, the elastic mean phase strains were measured during in-situ loading of a Cu-15 vol pct Mo particulatemetal-matrix composite (MMC) at 25 8C, 300 8C, and 350 8C. The degree of load sharing at each temperature was compar...