No abstract

Magnesia-doped lanthanum chromite is a potential material for use in solid oxide fuel cells as an interconnector due to its resistance to oxidation and reduction. The strength and toughness of La(Cr,,Mg,,,)O, were measured from 25" to 1000°C in the as-fired reduced state and after oxidation. The as-fired samples showed a peak in toughness of approximately 3.9 MPaem"' at 125°C which decreased to approximately 1.4 MPa.m"' at 600°C and 2.8 MPa-m"' at room temperature. This peak in toughness is hypothesized to be due to the rhombohedral-to-orthorhombic phase transition by a toughening mechanism that is currently being investigated. The strength was also affected by the phase transition for both the as-fired reduced and the oxidized samples.

The characteristics of dust particles deposited during the 2009 dust storm in the Gold Coast and Brisbane regions of Australia are discussed in this paper. The study outcomes provide important knowledge in relation to the potential impacts of dust storm related pollution on ecosystem health in the context that the frequency of dust storms is predicted to increase due to anthropogenic desert surface modifications and climate change impacts. The investigated dust storm contributed a large fraction of fine particles to the environment with an increased amount of total suspended solids, compared to dry deposition under ambient conditions. Although the dust storm passed over forested areas, the organic carbon content in the dust was relatively low. The primary metals present in the dust storm deposition were aluminium, iron and manganese, which are common soil minerals in Australia. The dust storm deposition did not contain significant loads of nickel, cadmium, copper and lead, which are commonly present in the urban environment. Furthermore, the comparison between the ambient and dust storm chromium and zinc loads suggested that these metals were contributed to the dust storm by local anthropogenic sources. The potential ecosystem health impacts of the 2009 dust storm include, increased fine solids deposition on ground surfaces resulting in an enhanced capacity to adsorb toxic pollutants as well as increased aluminium, iron and manganese loads. In contrast, the ecosystem health impacts related to organic carbon and other metals from dust storm atmospheric deposition are not considered to be significant.

No abstract

Quantitative X-ray powder diffractometry was applied to the phase analysis of a mineral specimen containing two sulfur-rich isomorphous mineral phases, beudantite [PbFe3(As04)-(so4)(0H),] and osarizawaite [PbFeA1C~(so~)~(oH),], together with goethite (FeOOH) and some hematite (Fez03). The application of the Rietveld method was extended to provide elemental as well as phase analysis.