Sol-gel derived oxides and mixed oxides catalysts with narrow mesoporous distribution

A novel sol-gel process for preparing oxides and mixed oxides sols from precipitation and peptization process is reported in this article. Inorganic salts are used as raw materials in this study. It is found that the amount of acid has great influence on the stability and particle diameter distribution of the precursor sols. Ultrasonic treatment is used to prepare alumina sol at room temperature. The result of Al-27 NMR shows that there exist Al-13(7+) species in the sol. By controlling the sol particles with narrow particle diameter distribution, alumina, titania and silica-alumina (SA) materials with narrow mesoporous distribution are formed by regular packing of sol particles during gelation without using any templates. The results also show that the structure and particle diameter distribution of precursor sol determine the final materials' texture.

Mixed reforming of heptane to syngas in the Ba0.5Sr0.5Co0.8Fe0.2O3 membrane reactor

Fuel cells are recognized as the most promising new power generation technology, but hydrogen supply is still a problem. In our previous work, we have developed a LiLaNiO/gamma-Al2O3 catalyst, which is excellent not only for partial oxidation of hydrocarbons, but also for steam reforming and autothermal reforming. However, the reaction needs pure oxygen or air as oxidant. We have developed a dense oxygen permeable membrane Ba0.5Sr0.5Co0.8Fe0.2O3 which has an oxygen permeation flux around 11.5 ml/cm(2) min at reaction conditions. Therefore, this work is to combine the oxygen permeable membrane with the catalyst LiLaNiO/gamma-Al2O3 in a membrane reactor for hydrogen production by mixed reforming of heptane. Under optimized reaction conditions, a heptane conversion of 100%, a CO selectivity of 91-93% and a H-2 selectivity of 95-97% have been achieved. (c) 2005 Elsevier B.V. All rights reserved.

In situ high temperature X-ray diffraction studies of mixed ionic and electronic conducting perovskite-type membranes

Phase structure and stability of three typical mixed ionic and electronic conducting perovskite-type membranes, SrCo0.8Fe0.2O3-delta (SCF), Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) and BaCo0.4Fe0.4Zr0.2O3-delta (BCFZ) were studied by in situ high temperature X-ray diffraction at temperatures from 303 to 1273 K and under different atmospheres (air, 2% O-2 in Ar and pure Ar) at 1173 K. By analyzing their lattice parameters the thermal expansion coefficients (TECs) of BSCF, SCF and BCZF are obtained to be 11.5 x 10(-6) K-1, 17.9 x 10(-6) K-1 and 10.3 x 10(-6) K-1, respectively. A relationship between phase stability and TEC was proposed: the higher is the TEC, the lower is the operation stability of the perovskite materials. (C) 2005 Elsevier B.V. All rights reserved.

Tan spot disease of wheat: race characterization.

2007

A feminist trade union agenda? The continued significance of class, gender and race.

During the 1990s attempts to identify a feminist trade union agenda have focused on both the content and process of such a potential agenda. In a period in which trade unions have changed significantly, the general national agenda appears to be changing, acknowledging issues of importance to women. UNISON, Britain's largest trade union, has enshrined proportionality and fair representation in its constitution, developing national initiatives aimed at improving opportunities in work and in the union for women, black workers, manual workers, disabled workers, etc. who traditionally have been less well represented. Many issues affecting women generally have moved to centre stage, yet issues affecting women ancillary workers seem as excluded as ever. Through a study of cleaners in the National Health Service this article argues that workplace interests reflect wider social divisions, but in a variety of patterns depending on the social organization of work. Despite thewidening trade union agenda, particular interests — more specifically the workplace interests of working-class women and black women — continue to be neglected.