91 research outputs found

    Role of Steps in N

    Get PDF
    Using adsorption experiments and density functional calculations we show that N-2 dissociation on the Ru(0001) surface is totally dominated by steps. The measured adsorption rate at the steps is at least 9 orders of magnitude higher than on the terraces at 500 K, and the corresponding calculated difference in activation energy is 1.5 eV. The low barrier at the step is shown to be due to a combination of electronic and geometrical effects. The consequences for Ru as a catalyst for ammonia synthesis are discussed

    Using adjustment to define preferred illuminances: do the results have any value?

    No full text
    The method of adjustment is examined as an approach to determine occupant illuminance preferences. From the results of previous studies using illuminance adjustment and recent studies performed purposely to investigate methodology, it is concluded that the method of adjustment has little value as a means of estimating the mean preferred illuminance. However, there is some evidence that when users are allowed to set their own light level that this enhances their satisfaction with the visual environment. Thus careful selection of the control variables (available range and initial value) offers the opportunity for reduced illuminances, and thus reduced energy consumption, whilst maintaining satisfaction
    • …
    corecore