Interaction of NO and NO2 with the surface of CexZr1−xO2 solid solutions – Influence of the phase composition

Structural (XRD) and spectroscopic (EPR, IR and Raman) investigations were performed to elucidate the influence of CeO₂ content on the phase composition and surface chemistry of Ce_xZr_1−xO₂ solid solutions (x = 0.10–0.85), interacting with NO and NO₂ in the absence and presence of oxygen. Strong influence of ceria loading on the adsorption modes of both nitrogen oxides and the nature of the resultant surface species was revealed. Adsorption of NO led to formation of mononitrosyl complexes, dimers and N₂O, whereas interaction of NO₂ with the ceria–zirconia catalyst resulted in the adsorbate disproportionation or coupling, depending on the sample composition.     

A Note on Line Search Termination Criteria for Collinear Scaling Algorithms

Ariyawansa [2] has introduced a line search termination criterion for collinear scaling minimization algorithms. However, he verified that this criterion provides sufficient decrease only in the case of objective functions that satisfy certain strong convexity assumptions. In this paper, we report results of our attempts to relax these assumptions. We present an example of a continuously differentiable, nonconvex function with bounded level sets on which the criterion of Ariyawansa [2] does not provide sufficient decrease. This example indicates that specifying line search termination criteria for collinear scaling algorithms is still an open problem. On a more positive note, we are able to show that the class of objective functions on which the criterion of Ariyawansa [2] provides sufficient decrease can be extended to include convex and strictly pseudo-convex functions. Received December 28, 2001; revised November 6, 2002 Published online: January 16, 2003     

The wear of thread guides by polyethylene terephthalate fibres

The processing of polyethylene terephthalate fibres filled with pigments causes wear of thread guides. To reduce this wear, the guides are provided with specially selected coatings, e.g. plasma-sprayed ceramics or hard-plated chromium.In the present study the wear of the coatings involved is described. The wear of the ceramic layers proves to be caused only by the abrasive action of the incorporated particles of the yarns. The wear of the chromium-plated layers also shows a corrosive element. A wear rate parameter is introduced which remains constant and is independent of a change in the different operating variables, such as pre-tension, angle of wrap and guide diameter. This parameter is based on the real area of contact between yarn and guide, which is mainly determined by the elastic deformation of the yarn.     

A risk factor study of coccidioidomycosis by controlling differential misclassifications of exposure and susceptibility using a landscape ecology approach

State-reported coccidioidomycosis cases in Arizona have dramatically increased since 1997, raising concerns about a possible epidemic, its cause, and associated risk factors, including spatio-temporal differences in susceptibility and exposure. This stratified, two-stage, cross-sectional study evaluates inherent, socio-economic, and environmental risk factors of coccidioidomycosis from information collected during an address-based telephone survey of 5460 households containing 14,105 individuals in greater Tucson, Arizona. Three geomorphic and two demographic strata controlled for differences in group-level exposures and susceptibility, and assured recruitment of a minority population. Logistic regression of self-reported cases indicates that location of residence by geomorphic and demographic strata was a risk factor that confounded the associations of coccidioidomycosis with age, race-ethnicity, and educational attainment. The risk due to age is more evenly distributed across the population than bivariate results when individual- and group-level exposure and susceptibility factors are controlled. Similarly the association for being Hispanic decreased from strong bivariate 0.28 odds ratio to a weak multivariate 0.75. Location of residence confounded the risk due to race-ethnicity and was an effect modifier of risk due to age. Differential misclassification of exposure to Coccidioides spores and susceptibility to coccidioidomycosis was reduced through landscape stratification by demographics and geomorphic types. Landscape epidemiological studies of diseases with strong environmental and demographic determinants can reduce residual confounding and account for spatial and temporal differences between neighborhoods and at broader scales.     

Adult age differences in sensitivity to semantic structure of prose.

50 18–33 yr olds and 43 62–67 yr olds from low- and high-education populations heard narrative passages at different presentation rates and difficulty levels in 2 experiments. Immediately after listening to a tape-recorded version of each story, Ss orally recalled it. Results consistently demonstrate that younger Ss remembered more than older ones, but Ss from all groups favored the main ideas in their recalls. Also, Ss from all ages and educational levels were equally able to identify the important information in the stories. It is suggested that sensitivity to the semantic structure of prose is not a major component of adult age differences in discourse comprehension. It is further suggested that adult age differences observed on discourse comprehension tasks may reflect an age-related decline in processing capacity. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)